Sample records for condition influence mating
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Consequences of snowy winters on male mating strategies and reproduction in a mountain ungulate.
Apollonio, Marco; Brivio, Francesca; Rossi, Iva; Bassano, Bruno; Grignolio, Stefano
2013-09-01
Alternative mating tactics (AMTs) are intrasexual variants in mating behaviour of several species ranging from arthropods to mammals. Male AMTs coexist between and within populations. In particular, male ungulates rarely adopt just one tactic throughout their lifetime. Tactics commonly change according to internal factors (age, body size, condition) and external conditions (weather, resources, predation, animal density). However, the influence of weather has not yet been investigated in upper vertebrates. Such influence may be relevant in species whose rutting period occurs late in fall or in winter, when environmental conditions and the snow cover in particular may vary considerably. We detected two AMTs in Alpine ibex (Capra ibex) males: older and full-grown males mainly adopted the tending tactic, while younger males usually pursued an alternative one (coursing tactic). Weather was found to influence the use of AMTs by males: in snowy mating seasons, the coursing tactic was no longer used due to difficulties in moving through deep snow. In snowy rutting periods, males appeared to delay or even avoid mating activities and a decrease of births was reported in the second part of the following birth season. Snow cover may have a negative effect on population dynamics by reducing the recruitment and on population genetic variability, as a consequence of poorer mating opportunities. Studies on factors affecting mating behaviour and leading to a reduced availability of mates and a decrease in female productivity are especially relevant in species, like Alpine ibex, whose genetic variability is low. Copyright © 2013 Elsevier B.V. All rights reserved.
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Non-random pairing in American kestrels: mate choice versus intra-sexual competition
Bortolotti, Gary R.; Iko, William M.
1992-01-01
Natural selection may influence the arrangement of individuals into mated pairs through either inter-sexual (mate choice) or intra-sexual selection (competition). A study of the American kestrel, Falco sparverius, in northern Saskatchewan distinguished between these two processes using size as a measure of the bird's competitive ability, and condition (mass scaled to body size) as an index of quality. Both sexes arrive on the study area after spring migration in equal numbers and males establish territories. Males and females that moved among territories at the time of pair formation were not different in size or condition from those that did not move, suggesting that birds were not being displaced by superior competitors, and that females moved to encounter potential mates. Within mated pairs, there was no relationship between a bird's size and the condition of its mate for either sex as would be predicted if intra-sexual competitition explained mating patterns. Instead, there was positive assortative mating by condition, suggesting that both sexes used quality as the criterion in choosing mates. There was no correlation between the sizes of males and females in mated paird. Because there were no differences in size or condition of breeding and non-breeding males, factors other than physical attributes, such as prior experience with the area, may determine a male's success in obtaining a territory. Because females that did not obtain mates were in poorer condition than those that did, males may have rejected poor quality females. The results suggest that intra-sexual competition was not important for pair formation, and that kestrels chose mates on the basis of quality.
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Duplouy, Anne; Woestmann, Luisa; Gallego Zamorano, Juan; Saastamoinen, Marjo
2018-04-01
In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality, and in some cases also to female body maintenance. The production of the spermatophore, however, represents a cost for the male and, in polyandrous species, ejaculates are sometimes allocated adaptively across matings. Nonetheless, although the ecological factors affecting the reproductive success of female butterflies have been the topic of numerous studies, little information exists on the factors affecting males' contribution to reproduction, and the indirect impacts on female fecundity and fitness. We used the Glanville fritillary butterfly, Melitaea cinxia (Linnaeus, 1758) (Nymphalidae), in order to assess variation in male allocation to matings. In this species, smaller males produce smaller spermatophores, but variation in spermatophore size is not correlated with female reproductive success. We show that spermatophore size increases with male age at first mating, decreases with mating frequency and adult food-deprivation, and is not influenced by developmental food-limitation. The length of copulation period does not influence the spermatophore size nor influences the polyandrous mating behavior in this species. Male contribution to his spermatophore size is clearly influenced by his condition and adult-resource at the time of mating. Despite this variation, spermatophore size does not seem to have a direct impact on female reproductive output or mating behavior. © 2016 The Authors Insect Science published by Wiley Publishing Asia Pty Ltd on behalf of Institute of Zoology, Chinese Academy of Sciences.
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Deaton, Raelynn
2009-01-01
I examined the effects of the parasitic larval nematode, Eustrongylides ignotus, on male mate choice in the western mosquitofish, Gambusia affinis. I hypothesized that parasite presence influences male mate choice either directly (via reduction in male mating behavior due to presence of parasite in females) or indirectly (via reduction in male mating behavior due to reduced condition of infected females). Specifically, I tested the predictions that (1) males would mate preferentially with uninfected over infected females (scoring both mating attempts and association time with females); (2) parasitized females would be in poorer condition than non-parasitized females (measured as soluble fat stores); and (3) parasitized females would have reduced fecundity (measured as number of developing embryos). Males preferred to mate with non-parasitized over parasitized females, but showed no differences in association time between females. The nematode did not decrease female body condition, but did decrease female mass, and appeared to decrease female fecundity via reduction in broods (# embryos). Results support that parasites affect male mate choice in mosquitofish; however, the mechanisms used by males to differentiate between parasitized and non-parasitized females remain untested. This study provides the first empirical evidence of parasite affects on male mate choice in livebearing fishes, and suggest a potentially important role for parasite-mediated sexual selection in organisms that use coercive mating as the primary mechanism of obtaining mates.
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When Love Meets Money: Priming the Possession of Money Influences Mating Strategies.
Li, Yi Ming; Li, Jian; Chan, Darius K-S; Zhang, Bo
2016-01-01
Money is an important factor that influences the development of romantic relationships. The current paper examines how the feeling of having relatively more or less money influences human mating strategies in long-term and short-term mating contexts under the framework of evolutionary psychology. We recruited mainland Chinese college students involved in steady, heterosexual romantic relationships to participate in two experiments. In each study, we experimentally triggered participants' feelings of having relatively more or less money and then examined their thoughts and behaviors related to mating. Results of Study 1 showed that men who were primed to feel that they had relatively more money were less satisfied with their partners' physical attractiveness than those primed to feel that they had less money, suggesting that the subjective feeling of having more or less money may affect men's preferences regarding the physical appearance of a mate in a long-term relationship. Interestingly, this difference was not significant for women. Results of Study 2 indicated that both men and women who were primed to feel that they had relatively more money exhibited a greater "behavioral approach tendency" toward an attractive member of the opposite sex than those primed to feel that they had less money. This finding suggests that people who feel they have relatively more money may have more interest in an attractive alternative than those who feel they have relatively less money. The differences in mating strategies between and within the genders brought about by money support the evolutionary hypothesis that individuals adopt conditional mating strategies in response to environmental conditions. Additionally, the results of experimental studies provide evidence for the causal effects of money on mating strategies. These findings have both conceptual and practical implications for the psychology of evolution and romantic relationships.
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When Love Meets Money: Priming the Possession of Money Influences Mating Strategies
Li, Yi Ming; Li, Jian; Chan, Darius K.-S.; Zhang, Bo
2016-01-01
Money is an important factor that influences the development of romantic relationships. The current paper examines how the feeling of having relatively more or less money influences human mating strategies in long-term and short-term mating contexts under the framework of evolutionary psychology. We recruited mainland Chinese college students involved in steady, heterosexual romantic relationships to participate in two experiments. In each study, we experimentally triggered participants' feelings of having relatively more or less money and then examined their thoughts and behaviors related to mating. Results of Study 1 showed that men who were primed to feel that they had relatively more money were less satisfied with their partners' physical attractiveness than those primed to feel that they had less money, suggesting that the subjective feeling of having more or less money may affect men's preferences regarding the physical appearance of a mate in a long-term relationship. Interestingly, this difference was not significant for women. Results of Study 2 indicated that both men and women who were primed to feel that they had relatively more money exhibited a greater “behavioral approach tendency” toward an attractive member of the opposite sex than those primed to feel that they had less money. This finding suggests that people who feel they have relatively more money may have more interest in an attractive alternative than those who feel they have relatively less money. The differences in mating strategies between and within the genders brought about by money support the evolutionary hypothesis that individuals adopt conditional mating strategies in response to environmental conditions. Additionally, the results of experimental studies provide evidence for the causal effects of money on mating strategies. These findings have both conceptual and practical implications for the psychology of evolution and romantic relationships. PMID:27047415
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Steiger, S; Capodeanu-Nägler, A; Gershman, S N; Weddle, C B; Rapkin, J; Sakaluk, S K; Hunt, J
2015-12-01
Indirect genetic benefits derived from female mate choice comprise additive (good genes) and nonadditive genetic benefits (genetic compatibility). Although good genes can be revealed by condition-dependent display traits, the mechanism by which compatibility alleles are detected is unclear because evaluation of the genetic similarity of a prospective mate requires the female to assess the genotype of the male and compare it to her own. Cuticular hydrocarbons (CHCs), lipids coating the exoskeleton of most insects, influence female mate choice in a number of species and offer a way for females to assess genetic similarity of prospective mates. Here, we determine whether female mate choice in decorated crickets is based on male CHCs and whether it is influenced by females' own CHC profiles. We used multivariate selection analysis to estimate the strength and form of selection acting on male CHCs through female mate choice, and employed different measures of multivariate dissimilarity to determine whether a female's preference for male CHCs is based on similarity to her own CHC profile. Female mating preferences were significantly influenced by CHC profiles of males. Male CHC attractiveness was not, however, contingent on the CHC profile of the choosing female, as certain male CHC phenotypes were equally attractive to most females, evidenced by significant linear and stabilizing selection gradients. These results suggest that additive genetic benefits, rather than nonadditive genetic benefits, accrue to female mate choice, in support of earlier work showing that CHC expression of males, but not females, is condition dependent. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.
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Choi, Kate H.; Tienda, Marta
2016-01-01
Despite theoretical consensus that marriage markets constrain mate selection behavior, few studies directly evaluate how local marriage market conditions influence intermarriage patterns. Using data from the American Community Survey, we examine what aspects of marriage markets influence mate selection; assess whether the associations between marriage market conditions and intermarriage are uniform by gender and across pan-ethnic groups; and investigate the extent to which marriage market conditions account for group differences in intermarriage patterns. Relative group size is the most salient and consistent determinant of intermarriage patterns across pan-ethnic groups and by gender. Marriage market constraints typically explain a larger share of pan-ethnic differences in intermarriage rates than individual traits, suggesting that scarcity of co-ethnic partners is a key reason behind decisions to intermarry. When faced with market constraints, men are more willing or more successful than women in crossing racial and ethnic boundaries in marriage. PMID:28579638
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Lechner, Christian; Ishiguro, Naoki; Fukuhara, Ayano; Shimizu, Hidetada; Ohtsu, Naoko; Takatani, Masahito; Nishiyama, Kotaro; Washio, Ikumi; Yamamura, Norio; Kusuhara, Hiroyuki
2016-08-01
Multidrug and toxin extrusion transporters (MATEs) have a determining influence on the pharmacokinetic profiles of many drugs and are involved in several clinical drug-drug interactions (DDIs). Cellular uptake assays with recombinant cells expressing human MATE1 or MATE2-K are widely used to investigate MATE-mediated transport for DDI assessment; however, the experimental conditions and used test substrates vary among laboratories. We therefore initially examined the impact of three assay conditions that have been applied for MATE substrate and inhibitor profiling in the literature. One of the tested conditions resulted in significantly higher uptake rates of the three test substrates, [(14)C]metformin, [(3)H]thiamine, and [(3)H]1-methyl-4-phenylpyridinium (MPP(+)), but IC50 values of four tested MATE inhibitors varied only slightly among the three conditions (<2.5-fold difference). Subsequently, we investigated the uptake characteristics of the five MATE substrates: [(14)C]metformin, [(3)H]thiamine, [(3)H]MPP(+), [(3)H]estrone-3-sulfate (E3S), and rhodamine 123, as well as the impact of the used test substrate on the inhibition profiles of 10 MATE inhibitors at one selected assay condition. [(3)H]E3S showed atypical uptake characteristics compared with those observed with the other four substrates. IC50 values of the tested inhibitors were in a similar range (<4-fold difference) when [(14)C]metformin, [(3)H]thiamine, [(3)H]MPP(+), or [(3)H]E3S were used as substrates but were considerably higher with rhodamine 123 (9.8-fold and 4.1-fold differences compared with [(14)C]metformin with MATE1 and MATE2-K, respectively). This study demonstrated for the first time that the impact of assay conditions on IC50 determination is negligible, that kinetic characteristics differ among used test substrates, and that substrate-dependent inhibition exists for MATE1 and MATE2-K, giving valuable insight into the assessment of clinically relevant MATE-mediated DDIs in vitro. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.
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Personal Characteristics Important in Mate Preference among College Students.
ERIC Educational Resources Information Center
Hoyt, Les Leanne; Hudson, John W.
1981-01-01
Compared college students' values in mate selection held today with those of earlier generations. Responses to a questionnaire (N=316) reflected changes in sex roles, influence of the mass media, increased idealization of romantic love, and current social and economic conditions. (Author/RC)
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Bird, Brian M; Carré, Justin M; Knack, Jennifer M; Arnocky, Steven
2016-01-01
Correlational research has linked low mate value (MV)--one's worth as a mating partner to members of the opposite sex--with aggression in men. In 2 experiments, we examined the effects of self-perceived MV on men's reported willingness to aggress directly toward a hypothetical mate poacher (Experiment 1, N = 60) and observable aggression toward a same-sex rival in a laboratory paradigm (Experiment 2, N = 54). In both experiments, the roles of narcissism in moderating the effect of MV condition on subsequent aggression were examined. Results of Experiment 1 indicated that men randomly assigned to the low MV condition were significantly more willing to report aggressive intention than men in the high MV condition. This relationship was moderated by narcissism such that men in the low MV condition who were also high in narcissism were the most likely to aggress. Results of Experiment 2 similarly showed that men in the low MV condition relative to the high MV condition aggressed more toward a same-sex rival when they were high in narcissism. These findings support evolutionary hypotheses surrounding the importance of self-perceived MV in directing aggressive mating efforts, as situated in the framework of threatened egotism.
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Maternal modulation of paternal effects on offspring development
Habrylo, Ireneusz B.; Gudsnuk, Kathryn M.; Pelle, Geralyn; Champagne, Frances A.
2018-01-01
The paternal transmission of environmentally induced phenotypes across generations has been reported to occur following a number of qualitatively different exposures and appear to be driven, at least in part, by epigenetic factors that are inherited via the sperm. However, previous studies of paternal germline transmission have not addressed the role of mothers in the propagation of paternal effects to offspring. We hypothesized that paternal exposure to nutritional restriction would impact male mate quality and subsequent maternal reproductive investment with consequences for the transmission of paternal germline effects. In the current report, using embryo transfer in mice, we demonstrate that sperm factors in adult food restricted males can influence growth rate, hypothalamic gene expression and behaviour in female offspring. However, under natural mating conditions females mated with food restricted males show increased pre- and postnatal care, and phenotypic outcomes observed during embryo transfer conditions are absent or reversed. We demonstrate that these compensatory changes in maternal investment are associated with a reduced mate preference for food restricted males and elevated gene expression within the maternal hypothalamus. Therefore, paternal experience can influence offspring development via germline inheritance, but mothers can serve as a modulating factor in determining the impact of paternal influences on offspring development. PMID:29514964
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Social influences on morphine conditioned place preference in adolescent mice.
Cole, Shannon L; Hofford, Rebecca S; Evert, Daniel J; Wellman, Paul J; Eitan, Shoshana
2013-03-01
Social/peer influences are among the strongest predictors of adolescent drug use. However, this important subject does not get much attention in pre-clinical studies. We recently observed that exposure to different social partners modulates morphine locomotor sensitization. Sensitivity to the hyper-locomotor response of drugs of abuse is a predictor of sensitivity to other drug-induced behaviors. Thus, this study examined how exposure to different social partners affected the rewarding properties of morphine. All animals were group-housed four per cage in one of two conditions referred to as 'only' and 'cage-mates'. In the mixed treatment condition, morphine- and saline-treated mice were housed together. These groups are referred to as 'morphine cage-mates' and 'saline cage-mates', respectively. In the separated treatment conditions, all mice in the cage received morphine (i.e. 'morphine only') or saline (i.e. 'saline only'), and cages were visually separated from each other. All animals were subsequently individually tested for the acquisition of morphine conditioned place preference (CPP) following one conditioning session with 10, 20 or 40 mg/kg morphine or saline. As expected, one conditioning session established morphine CPP in the morphine only animals, but not in the saline only animals. Notably, morphine CPP was not acquired by the morphine cage-mate animals. Additionally, 40 mg/kg morphine was sufficient to establish morphine CPP in the saline cage-mate animals. These results indicate that social environment has an effect on the rewarding properties of morphine. It suggests that exposure to different peers can alter the abuse potential of opioids and potentially other illicit drugs. © 2012 The Authors, Addiction Biology © 2012 Society for the Study of Addiction.
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HOW MATE AVAILABILITY INFLUENCES FILIAL CANNIBALISM.
Deal, Nicholas D S; Wong, Bob B M
2016-03-01
Parents sometimes eat their young to reduce the consequences of brood overcrowding, for nutritional gain, and/or to redirect investment toward future reproduction. It has been predicted that filial cannibalism should be more prevalent when mate availability is high as parents can more easily replace consumed young. Reviewing the available evidence--which comes almost exclusively from studies of paternal caring fish--we find support in some species, but not others. To explain this, we hypothesize that sexual selection against filial cannibalism and/or the tendency to acquire larger broods under conditions of high mate availability discourages filial cannibalism. Additionally, filial cannibalism might occur when mate availability is low to facilitate survival until access to mates improves. Since attractiveness can also influence remating opportunities, we review its effect on filial cannibalism, finding that attractive parents engage in less filial cannibalism. More research is needed to determine if this relationship is a result of individuals showing adaptive plasticity in filial cannibalism based on self-perceived attractiveness, or if the attractiveness of individuals is reduced by their propensity to commit filial cannibalism. More generally, to advance our understanding of how mate availability influences filial cannibalism, future studies should also focus on a wider range of taxa.
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Sperm economy between female mating frequency and male ejaculate allocation.
Abe, Jun; Kamimura, Yoshitaka
2015-03-01
Why females of many species mate multiply is a major question in evolutionary biology. Furthermore, if females accept matings more than once, ejaculates from different males compete for fertilization (sperm competition), which confronts males with the decision of how to allocate their reproductive resources to each mating event. Although most existing models have examined either female mating frequency or male ejaculate allocation while assuming fixed levels of the opposite sex's strategies, these strategies are likely to coevolve. To investigate how the interaction of the two sexes' strategies is influenced by the level of sperm limitation in the population, we developed models in which females adjust their number of allowable matings and males allocate their ejaculate in each mating. Our model predicts that females mate only once or less than once at an even sex ratio or in an extremely female-biased condition, because of female resistance and sperm limitation in the population, respectively. However, in a moderately female-biased condition, males favor partitioning their reproductive budgets across many females, whereas females favor multiple matings to obtain sufficient sperm, which contradicts the predictions of most existing models. We discuss our model's predictions and relationships with the existing models and demonstrate applications for empirical findings.
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Sex-biased parental investment is correlated with mate ornamentation in eastern bluebirds.
Ligon, Russell A; Hill, Geoffrey E
2010-03-01
Males typically have greater variance in reproductive success than females, so mothers should benefit by producing sons under favorable conditions. Being paired with a better-than-average mate is one such favorable circumstance. High-quality fathers can improve conditions for their offspring by providing good genes, good resources, or both, so females paired to such males should invest preferentially in sons. Ornamentation has been linked to male quality in many birds and, in support of differential allocation theory, females of several avian species invest more in entire broods when paired to attractive mates. Additionally, the females of some bird species apparently manipulate the primary sex-ratio of their broods in relation to the attractiveness of their mates. However, empirical support for a link between mate ornamentation and preferential feeding of sons (another form of biased investment) is lacking. We tested for correlations between sex-biased parental investment and mate plumage colour in the eastern bluebird (Sialia sialis), a species in which juveniles have sexually dichromatic UV-blue plumage. We found that the proportion of maternal feeding attempts to fledgling sons (versus fledgling daughters) was positively correlated with structurally coloured plumage ornamentation of fathers. Additionally, paternal feeding attempts to sons were correlated with plumage ornamentation of mothers and increased in fathers exhibiting breast plumage characteristics typical of older males. These results provide further support for the idea that parental strategies are influenced by mate attractiveness and provide the first evidence that mate ornamentation can influence parental behavior even after offspring have left the nest.
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A Method to Test the Effect of Environmental Cues on Mating Behavior in Drosophila melanogaster.
Gorter, Jenke A; Billeter, Jean-Christophe
2017-07-17
An individual's sexual drive is influenced by genotype, experience and environmental conditions. How these factors interact to modulate sexual behaviors remains poorly understood. In Drosophila melanogaster, environmental cues, such as food availability, affect mating activity offering a tractable system to investigate the mechanisms modulating sexual behavior. In D. melanogaster, environmental cues are often sensed via the chemosensory gustatory and olfactory systems. Here, we present a method to test the effect of environmental chemical cues on mating behavior. The assay consists of a small mating arena containing food medium and a mating couple. The mating frequency for each couple is continuously monitored for 24 h. Here we present the applicability of this assay to test environmental compounds from an external source through a pressurized air system as well as manipulation of the environmental components directly in the mating arena. The use of a pressurized air system is especially useful to test the effect of very volatile compounds, while manipulating components directly in the mating arena can be of value to ascertain a compound's presence. This assay can be adapted to answer questions about the influence of genetic and environmental cues on mating behavior and fecundity as well as other male and female reproductive behaviors.
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Sexual selection is influenced by both developmental and adult environments.
Gillespie, Stephanie R; Scarlett Tudor, M; Moore, Allen J; Miller, Christine W
2014-12-01
Sexual selection is often assumed to be strong and consistent, yet increasing research shows it can fluctuate over space and time. Few experimental studies have examined changes in sexual selection in response to natural environmental variation. Here, we use a difference in resource quality to test for the influence of past environmental conditions and current environmental conditions on male and female mate choice and resulting selection gradients for leaf-footed cactus bugs, Narnia femorata. We raised juveniles on natural high- and low-quality diets, cactus pads with and without ripe cactus fruits. New adults were again assigned a cactus pad with or without fruit, paired with a potential mate, and observed for mating behaviors. We found developmental and adult encounter environments affected mating decisions and the resulting patterns of sexual selection for both males and females. Males were not choosy in the low-quality encounter environment, cactus without fruit, but they avoided mating with small females in the high-quality encounter environment. Females were choosy in both encounter environments, avoiding mating with small males. However, they were the choosiest when they were in the low-quality encounter environment. Female mate choice was also context dependent by male developmental environment. Females were more likely to mate with males that had developed on cactus with fruit when they were currently in the cactus with fruit environment. This pattern disappeared when females were in the cactus without fruit environment. Altogether, these results experimentally demonstrate context-dependent mate choice by both males and females. Furthermore, we demonstrate that simple, seasonal changes in resources can lead to fluctuations in sexual selection. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.
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Female age and sperm competition: last-male precedence declines as female age increases.
Mack, Paul D; Priest, Nicholas K; Promislow, Daniel E L
2003-01-22
Until very recently, most studies of sperm competition have focused on variation in male competitive ability. However, we now know that a number of reproductive traits, including oviposition rate, use of stored sperm and receptivity to mating, vary with female condition. Because females can play an active part in the movement of sperm within their reproductive tract, sperm competition may be influenced by female condition. Existing studies of sperm competition in fruitflies ignore the effects of female condition, using females that are 3-4 days old and in their reproductive prime. But condition will decline as a female senesces. Here, we examine the effect of female age on the outcome of sperm competition in three strains of the fruitfly, Drosophila melanogaster. Previous studies have shown that female age influences preference for mates and male ejaculation strategies. In this study, we find that when males are mated to females that are older than 17 days, last-male sperm precedence decreases significantly. These results could lead to a greater understanding of the physiological mechanisms that regulate the outcome of sperm competition.
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Maternal modulation of paternal effects on offspring development.
Mashoodh, Rahia; Habrylo, Ireneusz B; Gudsnuk, Kathryn M; Pelle, Geralyn; Champagne, Frances A
2018-03-14
The paternal transmission of environmentally induced phenotypes across generations has been reported to occur following a number of qualitatively different exposures and appear to be driven, at least in part, by epigenetic factors that are inherited via the sperm. However, previous studies of paternal germline transmission have not addressed the role of mothers in the propagation of paternal effects to offspring. We hypothesized that paternal exposure to nutritional restriction would impact male mate quality and subsequent maternal reproductive investment with consequences for the transmission of paternal germline effects. In the current report, using embryo transfer in mice, we demonstrate that sperm factors in adult food restricted males can influence growth rate, hypothalamic gene expression and behaviour in female offspring. However, under natural mating conditions females mated with food restricted males show increased pre- and postnatal care, and phenotypic outcomes observed during embryo transfer conditions are absent or reversed. We demonstrate that these compensatory changes in maternal investment are associated with a reduced mate preference for food restricted males and elevated gene expression within the maternal hypothalamus. Therefore, paternal experience can influence offspring development via germline inheritance, but mothers can serve as a modulating factor in determining the impact of paternal influences on offspring development. © 2018 The Author(s).
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NASA Astrophysics Data System (ADS)
Rueppell, Olav; Phaincharoen, Mananya; Kuster, Ryan; Tingek, Salim
2011-09-01
During social evolution, the ovary size of reproductively specialized honey bee queens has dramatically increased while their workers have evolved much smaller ovaries. However, worker division of labor and reproductive competition under queenless conditions are influenced by worker ovary size. Little comparative information on ovary size exists in the different honey bee species. Here, we report ovariole numbers of freshly dissected workers from six Apis species from two locations in Southeast Asia. The average number of worker ovarioles differs significantly among species. It is strongly correlated with the average mating number of queens, irrespective of body size. Apis dorsata, in particular, is characterized by numerous matings and very large worker ovaries. The relation between queen mating number and ovary size across the six species suggests that individual selection via reproductive competition plays a role in worker ovary size evolution. This indicates that genetic diversity, generated by multiple mating, may bear a fitness cost at the colony level.
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Cocco, Arturo; Muscas, Enrico; Mura, Alessandra; Iodice, Andrea; Savino, Francesco; Lentini, Andrea
2018-05-08
Although mating disruption is increasingly being used to control the worldwide grapevine pest vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), its mode of action remains unclear. A three-year field experiment was carried out to investigate the effects of mating disruption on the development and reproduction of the vine mealybug. The influence of mating disruption applied over consecutive years on the pest population density was also evaluated. The percentage of ovipositing females was significantly reduced in disrupted plots by 18.8-66.2%, depending on the year. The absence of ovipositing females in disrupted plots in the autumn of the second and third year indicates the effectiveness of mating disruption throughout the whole growing season. Mating disruption consistently prolonged the pre-oviposition period in all years by up to 12.5 days. Our findings provide new insights into the mechanisms underlying the pheromone-based control of the vine mealybug and indicate that the reduction of the pest population density is due to both a decrease and delay in female mating. In addition, the population density of vine mealybugs under mating disruption decreased over years, indicating that consecutive applications of this control strategy would significantly increase the effectiveness of controlling the vine mealybug by mating disruption. This article is protected by copyright. All rights reserved.
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2012-01-01
Sexual selection is a major force driving evolution and is intertwined with ecological factors. Differential allocation of limited resources has a central role in the cost of reproduction. In this paper, I review the costs and benefits of mating in tettigoniids, focussing on nuptial gifts, their trade-off with male calling songs, protandry and how mate density influences mate choice. Tettigoniids have been widely used as model systems for studies of mating costs and benefits; they can provide useful general insights. The production and exchange of large nuptial gifts by males for mating is an important reproductive strategy in tettigoniids. As predicted by sexual selection theory spermatophylax size is condition dependent and is constrained by the need to invest in calling to attract mates also. Under some circumstances, females benefit directly from the nuptial gifts by an increase in reproductive output. However, compounds in the nuptial gift can also benefit the male by prolonging the period before the female remates. There is also a trade-off between adult male maturation and mating success. Where males mature before females (protandry) the level of protandry varies in the direction predicted by sperm competition theory; namely, early male maturation is correlated with a high level of first inseminations being reproductively successful. Lastly, mate density in bushcrickets is an important environmental factor influencing the behavioural decisions of individuals. Where mates are abundant, individuals are more choosey of mates; when they are scarce, individuals are less choosey. This review reinforces the view that tettigoniids provide excellent models to test and understand the economics of matings in both sexes. PMID:22894685
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Zietsch, Brendan P.; Verweij, Karin J. H.; Heath, Andrew C.; Martin, Nicholas G.
2012-01-01
Human mate choice is central to individuals’ lives and to the evolution of the species, but the basis of variation in mate choice is not well understood. Here we look at a large community-based sample of twins and their partners and parents (N > 20,000 individuals) to test for genetic and family environmental influences on mate choice, with and without controlling for the effects of assortative mating. Key traits are analyzed, including height, body mass index, age, education, income, personality, social attitudes, and religiosity. This revealed near-zero genetic influences on male and female mate choice over all traits and no significant genetic influences on mate choice for any specific trait. A significant family environmental influence was found for the age and income of females’ mate choices, possibly reflecting parental influence over mating decisions. We also tested for evidence of sexual imprinting, where individuals acquire mate-choice criteria during development by using their opposite-sex parent as the template of a desirable mate; there was no such effect for any trait. The main discernable pattern to mate choice was assortative mating; we found that partner similarity was due to initial choice rather than convergence and also due at least in part to phenotypic matching. PMID:21508607
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Zietsch, Brendan P; Verweij, Karin J H; Heath, Andrew C; Martin, Nicholas G
2011-05-01
Human mate choice is central to individuals' lives and to the evolution of the species, but the basis of variation in mate choice is not well understood. Here we looked at a large community-based sample of twins and their partners and parents ([Formula: see text] individuals) to test for genetic and family environmental influences on mate choice, while controlling for and not controlling for the effects of assortative mating. Key traits were analyzed, including height, body mass index, age, education, income, personality, social attitudes, and religiosity. This revealed near-zero genetic influences on male and female mate choice over all traits and no significant genetic influences on mate choice for any specific trait. A significant family environmental influence was found for the age and income of females' mate choices, possibly reflecting parental influence over mating decisions. We also tested for evidence of sexual imprinting, where individuals acquire mate-choice criteria during development by using their opposite-sex parent as the template of a desirable mate; there was no such effect for any trait. The main discernible pattern of mate choice was assortative mating; we found that partner similarity was due to initial choice rather than convergence and also at least in part to phenotypic matching.
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Bailey, Richard I; Innocenti, Paolo; Morrow, Edward H; Friberg, Urban; Qvarnström, Anna
2011-02-28
The evolution of female choice mechanisms favouring males of their own kind is considered a crucial step during the early stages of speciation. However, although the genomics of mate choice may influence both the likelihood and speed of speciation, the identity and location of genes underlying assortative mating remain largely unknown. We used mate choice experiments and gene expression analysis of female Drosophila melanogaster to examine three key components influencing speciation. We show that the 1,498 genes in Zimbabwean female D. melanogaster whose expression levels differ when mating with more (Zimbabwean) versus less (Cosmopolitan strain) preferred males include many with high expression in the central nervous system and ovaries, are disproportionately X-linked and form a number of clusters with low recombination distance. Significant involvement of the brain and ovaries is consistent with the action of a combination of pre- and postcopulatory female choice mechanisms, while sex linkage and clustering of genes lead to high potential evolutionary rate and sheltering against the homogenizing effects of gene exchange between populations. Taken together our results imply favourable genomic conditions for the evolution of reproductive isolation through mate choice in Zimbabwean D. melanogaster and suggest that mate choice may, in general, act as an even more important engine of speciation than previously realized.
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Carter, Alecia J; Wilson, Robbie S
2006-12-01
Few studies have examined the adaptive significance of reversible acclimation responses. The aerobic performance and mating behaviour of the sexually coercive male eastern mosquito fish (Gambusia holbrooki) offers an excellent model system for testing the benefits of reversible acclimation responses to mating success. We exposed male mosquito fish to normoxic or hypoxic conditions for 4 weeks and tested their maximum sustained swimming performance and their ability to obtain coercive matings under both normoxic and hypoxic conditions. We predicted that hypoxia-acclimated males would possess greater swimming and mating performance in hypoxic conditions than normoxic-acclimated males, and vice versa when tested in normoxia. Supporting our predictions, we found the sustained swimming performance of male mosquito fish was greater in a hypoxic environment following long-term exposure to low partial pressures of oxygen. However, the benefits of acclimation responses to mating performance were dependent on whether they were tested in the presence or absence of male-male competition. In a non-competitive environment, male mosquito fish acclimated to hypoxic conditions spent a greater amount of time following females and obtained more copulations than normoxic-acclimated males when tested in low partial pressures of oxygen. When males were competed against each other for copulations, we found no influence of long-term exposure to different partial pressures of oxygen on mating behaviour. Thus, despite improvements in the aerobic capacity of male mosquito fish following long-term acclimation to hypoxic conditions, these benefits did not always manifest themselves in improved mating performance. This study represents one of the first experimental tests of the benefits of reversible acclimation responses, and indicates that the ecological significance of physiological plasticity may be more complicated than previously imagined.
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Mate Choice in Mus musculus Is Relative and Dependent on the Estrous State
Zinck, Léa; Lima, Susana Q.
2013-01-01
Mate choice is a critical behavioral decision process with profound impact on evolution. However, the mechanistic basis of mate choice is poorly understood. In this study we focused on assortative mate choice, which is known to contribute to the reproductive isolation of the two European subspecies of house mouse, Mus musculus musculus and Mus musculus domesticus. To understand the decision process, we developed both full mating and limited-contact paradigms and tested musculus females' preference for musculus versus domesticus males, mimicking the natural musculus/domesticus contact zone. As hypothesized, when allowed to mate we found that sexually receptive musculus females exhibited a robust preference to mate with musculus males. In contrast, when non-receptive, females did not exhibit a preference and rather alternated between males in response to male mount attempts. Moreover in a no-choice condition, females mated readily with males from both subspecies. Finally, when no physical contact was allowed, and therefore male's behavior could not influence female's behavior, female's preference for its own subspecies was maintained independently of the estrous state. Together, our results suggest that the assortative preference is relative and based on a comparison of the options available rather than on an absolute preference. The results of the limited-contact experiments highlight the interplay between female's internal state and the nature of the interaction with prospective mates in the full mating conditions. With these experiments we believe we established an assortative mate preference assay that is appropriate for the investigation of its underlying substrates. PMID:23762466
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Maklakov, Alexei A; Lubin, Yael
2004-05-01
Female multiple mating (polyandry) is a widespread but costly behavior that remains poorly understood. Polyandry may arise when whatever benefits females accrue from multiple mating outweigh the costs, or males manipulate females against the females' best interests. In a polyandrous spider Stegodyphus lineatus females may mate with up to five males, but behave aggressively toward additional males after the first mating. Female aggressiveness may act to select for better quality males. Alternatively, females may try to avoid superfluous matings. To test these alternatives, we allocated females into single-mating (SM) and double-mating treatments. Double-mated females either accepted (DM) or rejected (RE) the second male. DM females laid more eggs, but did not produce more offspring than SM and RE females. Offspring of DM females were smaller at dispersal than offspring of SM and RE females. Also, nest failure was significantly more common in DM females. Paternal variables did not influence female reproductive success, whereas maternal body condition explained much of the variation. We show that polyandry is costly for females despite the production of larger clutches and suggest that multiple mating results from male manipulation of female remating behavior.
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Keiser, Carl N.; Pinter-Wollman, Noa; Augustine, David A.; Ziemba, Michael J.; Hao, Lingran; Lawrence, Jeffrey G.; Pruitt, Jonathan N.
2016-01-01
Despite the importance of host attributes for the likelihood of associated microbial transmission, individual variation is seldom considered in studies of wildlife disease. Here, we test the influence of host phenotypes on social network structure and the likelihood of cuticular bacterial transmission from exposed individuals to susceptible group-mates using female social spiders (Stegodyphus dumicola). Based on the interactions of resting individuals of known behavioural types, we assessed whether individuals assorted according to their behavioural traits. We found that individuals preferentially interacted with individuals of unlike behavioural phenotypes. We next applied a green fluorescent protein-transformed cuticular bacterium, Pantoea sp., to individuals and allowed them to interact with an unexposed colony-mate for 24 h. We found evidence for transmission of bacteria in 55% of cases. The likelihood of transmission was influenced jointly by the behavioural phenotypes of both the exposed and susceptible individuals: transmission was more likely when exposed spiders exhibited higher ‘boldness’ relative to their colony-mate, and when unexposed individuals were in better body condition. Indirect transmission via shared silk took place in only 15% of cases. Thus, bodily contact appears key to transmission in this system. These data represent a fundamental step towards understanding how individual traits influence larger-scale social and epidemiological dynamics. PMID:27097926
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Keiser, Carl N; Pinter-Wollman, Noa; Augustine, David A; Ziemba, Michael J; Hao, Lingran; Lawrence, Jeffrey G; Pruitt, Jonathan N
2016-04-27
Despite the importance of host attributes for the likelihood of associated microbial transmission, individual variation is seldom considered in studies of wildlife disease. Here, we test the influence of host phenotypes on social network structure and the likelihood of cuticular bacterial transmission from exposed individuals to susceptible group-mates using female social spiders (Stegodyphus dumicola). Based on the interactions of resting individuals of known behavioural types, we assessed whether individuals assorted according to their behavioural traits. We found that individuals preferentially interacted with individuals of unlike behavioural phenotypes. We next applied a green fluorescent protein-transformed cuticular bacterium,Pantoeasp., to individuals and allowed them to interact with an unexposed colony-mate for 24 h. We found evidence for transmission of bacteria in 55% of cases. The likelihood of transmission was influenced jointly by the behavioural phenotypes of both the exposed and susceptible individuals: transmission was more likely when exposed spiders exhibited higher 'boldness' relative to their colony-mate, and when unexposed individuals were in better body condition. Indirect transmission via shared silk took place in only 15% of cases. Thus, bodily contact appears key to transmission in this system. These data represent a fundamental step towards understanding how individual traits influence larger-scale social and epidemiological dynamics. © 2016 The Author(s).
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Effects of polygamy on the activity/rest rhythm of male fruit flies Drosophila melanogaster
NASA Astrophysics Data System (ADS)
Vartak, Vivek Rohidas; Varma, Vishwanath; Sharma, Vijay Kumar
2015-02-01
Although polygamy is common in insects, its extent varies enormously among natural populations. Mating systems influence the evolution of reproductive traits and the difference in extent of polygamy between males and females may be a key factor in determining traits which come under the influence of sexual selection. Fruit flies Drosophila melanogaster are promiscuous as both males and females mate with multiple partners. Mating has severe consequences on the physiology and behaviour of flies, and it affects their activity/rest rhythm in a sex-specific manner. In this study, we attempted to discern the effects of mating with multiple partners as opposed to a single partner, or of remaining unmated, on the activity/rest rhythm of flies under cyclic semi-natural (SN) and constant dark (DD) conditions. The results revealed that while evening activity of mated flies was significantly reduced compared to virgins, polygamous males showed a more severe reduction compared to monogamous males. In contrast, though mated females showed reduction in evening activity compared to virgins, activity levels were not different between polygamous and monogamous females. Although there was no detectable effect of mating on clock period, power of the activity/rest rhythm was significantly reduced in mated females with no difference seen between polygamous and monogamous individuals. These results suggest that courtship motivation, represented by evening activity, is successively reduced in males due to mating with one or more partners, while in females, it does not depend on the number of mating partners. Based on these results we conclude that polygamy affects the activity/rest rhythm of fruit flies D. melanogaster in a sex-dependent manner.
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Barbosa, Julierme Z; Motta, Antonio C V; Consalter, Rangel; Poggere, Giovana C; Santin, Delmar; Wendling, Ivar
2018-01-01
Native to subtropical region of South America, yerba mate is responsive to P under some conditions, but the degree of influence of genetic and soil on the growth and composition of the leaf is unknown. The aim of study was to evaluate plant growth, nutrients and potentially toxic elements in leaves of yerba mate clones in response to P application in acid soils. In greenhouse condition, two yerba mate clone seedlings were grown (210 days) in pots, each clone in a completely randomized design in factorial scheme (with and without P; four acid soils). The elemental composition of leaves and the growth of plants were determined. Phosphorus promoted plant growth, but this was not accompanied by increased P in leaf tissue in all conditions tested. The P effect on the elemental composition varied: decrease/null (N, K, Mg, Mn, Cu, Ni, B, Mo, Al, Cd); increase/null (C/N, C, Ca, Fe, V); increase/decrease/null (Zn, Ba, Pb) and; null (Cr). The soils affect the elemental composition of the leaves, especially Mn, with accumulation greater than 1000 mg kg-1. The Ba, Pb, Al and Zn in the leaves varied among clones. Yerba mate response to P was affected by edaphic and plant factors.
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Jayaweera, Anuradhi; Barry, Katherine L.
2015-01-01
Strategic ejaculation is a behavioural strategy shown by many animals as a response to sperm competition and/or as a potential mechanism of cryptic male choice. Males invest more mating resources when the risk of sperm competition increases or they invest more in high quality females to maximize their reproductive output. We tested this hypothesis in the false garden mantid Pseudomantis albofimbriata, where females are capable of multiply mating and body condition is an indicator of potential reproductive fitness. We predicted male mantids would ejaculate strategically by allocating more sperm to high quality females. To determine if and how males alter their ejaculate in response to mate quality, we manipulated female food quantity so that females were either in good condition with many eggs (i.e. high quality) or poor condition with few eggs (i.e. low quality). Half of the females from each treatment were used in mating trials in which transferred sperm was counted before fertilisation occurred and the other half of females were used in mating trials where fertilisation occurred and ootheca mass and total eggs in the ootheca were recorded. Opposed to our predictions, the total number of sperm and the proportion of viable sperm transferred did not vary significantly between female treatments. Male reproductive success was entirely dependent on female quality/fecundity, rather than on the number of sperm transferred. These results suggest that female quality is not a major factor influencing postcopulatory male mating strategies in P. albofimbriata, and that sperm number has little effect on male reproductive success in a single mating scenario. PMID:25970459
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Cunningham, C B; Douthit, M K; Moore, A J
2014-01-01
Flexible behaviour allows organisms to respond appropriately to changing environmental and social conditions. In the subsocial beetle Nicrophorus vespilloides, females tolerate conspecifics when mating, become aggressive when defending resources, and return to social tolerance when transitioning to parenting. Given the association between octopamine and aggression in insects, we hypothesized that genes in the octopaminergic system would be differentially expressed across different social and reproductive contexts. To test this in N. vespilloides, we first obtained the sequences of orthologues of the synthetic enzymes and receptors of the octopaminergic system. We next compared relative gene expression from virgin females, mated females, mated females alone on a resource required for reproduction and mated females on a resource with a male. Expression varied for five receptor genes. The expression of octopamine β receptor 1 and octopamine β receptor 2 was relatively higher in mated females than in other social conditions. Octopamine β receptor 3 was influenced by the presence or absence of a resource and less by social environment. Octopamine α receptor and octopamine/tyramine receptor 1 gene expression was relatively lower in the mated females with a resource and a male. We suggest that in N. vespilloides the octopaminergic system is associated with the expression of resource defence, alternative mating tactics, social tolerance and indirect parental care. PMID:24646461
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Chuang, Ming-Feng; Bee, Mark A; Kam, Yeong-Choy
2013-01-01
Mating duration is a reproductive behaviour that can impact fertilization efficiency and offspring number. Previous studies of factors influencing the evolution of mating duration have focused on the potential role of internal sperm competition as an underlying source of selection; most of these studies have been on invertebrates. For vertebrates with external fertilization, such as fishes and frogs, the sources of selection acting on mating duration remain largely unknown due, in part, to the difficulty of observing complete mating behaviours in natural conditions. In this field study, we monitored breeding activity in a population of the territorial olive frog, Rana adenopleura, to identify factors that affect the duration of amplexus. Compared with most other frogs, amplexus was short, lasting less than 11 min on average, which included about 8 min of pre-oviposition activity followed by 3 min of oviposition. We evaluated the relationship between amplexus duration and seven variables: male body size, male condition, operational sex ratio (OSR), population size, clutch size, territory size, and the coverage of submerged vegetation in a male's territory. We also investigated the influence of these same variables, along with amplexus duration, on fertilization rate. Amplexus duration was positively related with clutch size and the degree of male-bias in the nightly OSR. Fertilization rate was directly related to male body size and inversely related to amplexus duration. Agonistic interactions between males in amplexus and intruding, unpaired males were frequent. These interactions often resulted in mating failure, prolonged amplexus duration, and reduced fertilization rates. Together, the pattern of our findings indicates short amplexus duration in this species may be an adaptive reproductive strategy whereby males attempt to reduce the risks of mating and fertilization failures and territory loss resulting from male-male competition.
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Hernández, Emilio; Liedo, Pablo; Toledo, Jorge; Montoya, Pablo; Perales, Hugo; Ruiz-Montoya, Lorena
2017-12-05
The sterile insect technique uses males that have been mass-reared in a controlled environment. The insects, once released in the field, must compete to mate. However, the mass-rearing condition supposes a loss of fitness that will be noticeable by wild females. To compare the fitness of wild males and mass-reared males, three competition settings were established. In setting 1, wild males, mass-reared males and wild females were released in field cages. In setting 2, wild females and wild males were released without competition, and in setting 3, mass-reared males and mass-reared females were also released without competition. Male fitness was based on their mating success, fecundity, weight and longevity. The fitness of the females was measured based on weight and several demographic parameters. The highest percentage of mating was between wild males and wild females between 0800 and 0900 h in the competition condition, while the mass-reared males started one hour later. The successful wild males weighed more and showed longer mating times, greater longevity and a higher number of matings than the mass-reared males. Although the mass-reared males showed the lowest percentage of matings, their fecundity when mating with wild females indicated a high fitness. Since the survival and fecundity of wild females that mated with mass-reared males decreased to become similar to those of mass-reared females that mated with mass-reared males, females seem to be influenced by the type of male (wild or mass-reared). © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Tibbetts, Elizabeth A; Mettler, Alexander; Donajkowski, Kellie
2013-03-01
The reproductive ground plan hypothesis (RGPH) proposes that the ovarian cycle in solitary insects provides the basis for social evolution, so similar mechanisms are predicted to influence reproductive plasticity in social and solitary species. Specifically, reproductive plasticity in social species originated via modification of nutrition-dependent fertility response to juvenile hormone (JH) in solitary insects. Testing this prediction requires information about the factors that influence fertility in non-social relatives of the eusocial hymenoptera. However, no previous studies have examined how JH or nutritional condition influence fertility in Eumenines, the non-social group most closely related to social wasps. Here, we find support for the RGPH, as JH increases Euodynerus foraminatus fertility. Fertility is also condition-dependent, as heavy E. foraminatus are more fertile than light E. foraminatus. In addition, we measure the factors associated with mating success in E. foraminatus, finding that multiple factors influence mating success, including male weight, male mating experience, and female age. There is also higher variance in male than female reproductive success, suggesting that males may experience substantial sexual selection in this species. Overall, the relationships between JH, body weight, and fertility in E. foraminatus support the RGPH for the origin of sociality by demonstrating that there are strong parallels in the mechanisms that mediate fertility of social and non-social wasps. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Hubbard, Joanna K; Jenkins, Brittany R; Safran, Rebecca J
2015-01-01
Phenotypic differences among individuals are often linked to differential survival and mating success. Quantifying the relative influence of genetic and environmental variation on phenotype allows evolutionary biologists to make predictions about the potential for a given trait to respond to selection and various aspects of environmental variation. In particular, the environment individuals experience during early development can have lasting effects on phenotype later in life. Here, we used a natural full-sib/half-sib design as well as within-individual longitudinal analyses to examine genetic and various environmental influences on plumage color. We find that variation in melanin-based plumage color – a trait known to influence mating success in adult North American barn swallows (Hirundo rustica erythrogaster) – is influenced by both genetics and aspects of the developmental environment, including variation due to the maternal phenotype and the nest environment. Within individuals, nestling color is predictive of adult color. Accordingly, these early environmental influences are relevant to the sexually selected plumage color variation in adults. Early environmental conditions appear to have important lifelong implications for individual reproductive performance through sexual signal development in barn swallows. Our results indicate that feather color variation conveys information about developmental conditions and maternal care alleles to potential mates in North American barn swallows. Melanin-based colors are used for sexual signaling in many organisms, and our study suggests that these signals may be more sensitive to environmental variation than previously thought. PMID:26380676
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Does egg colouration reflect male condition in birds?
NASA Astrophysics Data System (ADS)
Martínez-Padilla, Jesús; Dixon, Heather; Vergara, Pablo; Pérez-Rodríguez, Lorenzo; Fargallo, Juan A.
2010-05-01
How colouration provides information about individuals in birds has been a central issue in recent decades. Although much information has been derived, little is known about the adaptive significance of egg colouration in birds. A recent idea suggests that biliverdin- and porphyrin-pigmented eggs may act as a post-mating sexual signal for males to assess female quality. In birds, it is common for males to influence prelaying female condition by courtship feeding. Using Eurasian kestrels, a species that lays protoporphyrin-pigmented eggs, we descriptively assessed the influence of male feeding on egg pigmentation by considering female phenotype, condition, breeding parameters and male body condition. We found that older females and females with greyer tails (an index of individual quality) produce highly pigmented eggs. However, male body condition was the only variable that explained egg colouration when considered together with the female-related variables. Therefore, females that mated with males in better condition laid highly pigmented eggs. With the same species, we also explored the cost of producing protoporphyrin-pigmented eggs using a food-supply experiment before the laying period. Food supplementation did not increase egg pigmentation, but hatching success and egg mass were positively related to egg colouration only in food supplied pairs. We suggest that egg colouration might be costly to produce and probably suggests egg quality. However, this cost cannot be explained by female quality, but by male condition instead. In general, our results do not support the theory that egg colouration is a post-mating sexual signal in species where males determine female condition at the time of laying.
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Subramoniam, T
2013-12-01
Crustaceans are known for their unrivalled diversity of sexual systems, as well as peculiar mating associations to achieve maximum mating success and fertilization accomplishment. Although sexes are separate in most species, various types of hermaphroditism characterize these predominantly aquatic arthropods. A low operational sex ratio between female and male, together with temporally limited receptivity of females towards males, imposes restrictions on the structuring of mating systems in crustaceans. The basic mating systems consist of monogamy, polygamy, mate guarding and pure searching. Understandably, ecological influences may also play a determinative role in the evolution of such sexual and mating systems in crustaceans. An important outcome of the crustacean sexual biology is the development of complex social structures in many aquatic species, in much the same way insects have established them in terrestrial conditions. In addition, groups like isopods and certain families of brachyuran crabs have shown terrestrial adaptation, exhibiting peculiar reproductive modes, sometimes reminiscent of their terrestrial counterparts, insects. Many caridean shrimps, living in symbiotic relationship with other marine invertebrates in the coral reef habitats, have reached pinnacle of complexity in sexuality and peculiar mating behaviours, resulting in communal living and establishing advanced social systems, such as eusociality.
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Sex-Linked Mating Strategies Diverge with a Manipulation of Genital Salience.
Fetterman, Adam K; Kruger, Nicole N; Robinson, Michael D
2015-02-01
Trivers (1972) proposed that evolutionary factors should favor divergent mating strategies for males versus females. Such differences may be less pronounced among human beings than other animals and social norms and sex roles are also pertinent influences. The present experiment ( N = 133 college undergraduates, 74 female) sought to bypass some of these other influences. Participants were randomly assigned to a condition designed to increase attention to the genital region (a downward pointing arrow) or not (an upward pointing arrow). They then reported on their interest in short-term (e.g., a one-night stand) and long-term (e.g., a potential marital partner) mating opportunities. A theory-consistent three-way interaction occurred such that the genital salience manipulation primed a shorter-term reproductive strategy among men and a longer-term reproductive strategy among women. The results provide unique support for evolution-linked ideas about sex differences in the form of a role for bodily attention.
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Auld, J R; Helker, A D; Kolpas, A
2016-12-01
Senescence is not a static property of an individual or population, but rather it is a dynamic process that may be influenced by environmental conditions. This can occur in at least two ways: in the long-term across multiple generations, and in the short-term via phenotypic plasticity. The former has attracted a lot of attention, both theoretically and empirically; the latter has lagged behind. To determine whether two important environmental variables (predation risk and mate availability) affect the pattern of actuarial senescence (i.e. the increase in mortality with age), we reared 30 full-sib families of the simultaneously hermaphroditic freshwater snail Physa acuta under four different environmental conditions and tracked individuals until death. Individuals were reared in a 2×2 factorial experiment that manipulated the nonlethal presence of chemical cues from predatory crayfish (presence/absence) and the opportunity to mate with an unrelated partner (mated/not mated). Snails that receive a partner reproduce by outcrossing, whereas those that remain in isolation can reproduce by self-fertilization. We compared the cumulative survival curves to test for an effect of predation risk and mating. The hazard ratio (HR) for the predation risk comparison was 1.042 indicating no significant difference between the curves. However, the HR for the mating comparison was 4.021, reflecting a significant reduction in survival probability for mated snails relative to isolated snails. As such, mating resulted in a much shorter lifespan, an outcome that we interpret in terms of shifting resource allocation. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.
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Evolution of mating systems in coral reef gobies and constraints on mating system plasticity
NASA Astrophysics Data System (ADS)
Hernaman, V.; Munday, P. L.
2007-09-01
Social and mating systems can be influenced by the distribution, abundance, and economic defendability of breeding partners and essential resources. Polygyny is predicted where males can economically defend multiple females or essential resources used by females. In contrast, monogamy is predicted where neither sex can monopolise multiple partners, either directly or through resource control, but where one mate is economically defendable. The mating system and reproductive behaviour of five species of coral reef goby were investigated and contrasted with population density and individual mobility. The two most abundant species ( Asterropteryx semipunctatus and Istigobius goldmanni) were polygynous. In contrast, the less populous and more widely dispersed epibenthic species ( Amblygobius bynoensis, Amblygobius phalaena and Valenciennea muralis) were pair forming and monogamous. All five species had low mobility, mostly remaining within metres (3 epibenthic species) or centimetres (2 cryptobenthic species) of a permanent shelter site. Interspecific differences in the mating system may have been shaped by differences in population density and the ability of reproductive individuals to economically defend breeding partners/sites. However, in a test of mating system plasticity, males of the three monogamous species did not mate polygynously when given the opportunity to do so in experimental manipulations of density and sex ratio. Mate guarding and complex spawning characteristics, which have likely co-evolved with the monogamous mating system, could contribute to mating system inflexibility by making polygynous mating unprofitable for individuals of the pair forming species, even when presented with current-day ecological conditions that usually favour polygyny.
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Condition-dependent mate choice: A stochastic dynamic programming approach.
Frame, Alicia M; Mills, Alex F
2014-09-01
We study how changing female condition during the mating season and condition-dependent search costs impact female mate choice, and what strategies a female could employ in choosing mates to maximize her own fitness. We address this problem via a stochastic dynamic programming model of mate choice. In the model, a female encounters males sequentially and must choose whether to mate or continue searching. As the female searches, her own condition changes stochastically, and she incurs condition-dependent search costs. The female attempts to maximize the quality of the offspring, which is a function of the female's condition at mating and the quality of the male with whom she mates. The mating strategy that maximizes the female's net expected reward is a quality threshold. We compare the optimal policy with other well-known mate choice strategies, and we use simulations to examine how well the optimal policy fares under imperfect information. Copyright © 2014 Elsevier Inc. All rights reserved.
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Male mate choice influences female promiscuity in Soay sheep
Preston, B.T.; Stevenson, I.R.; Pemberton, J.M.; Coltman, D.W.; Wilson, K.
2005-01-01
In most animal species, males are predicted to compete for reproductive opportunities, while females are expected to choose between potential mates. However, when males’ rate of reproduction is constrained, or females vary widely in ‘quality’, male mate choice is also predicted to occur. Such conditions exist in the promiscuous mating system of feral Soay sheep on St Kilda, Scotland, where a highly synchronized mating season, intense sperm competition and limitations on sperm production constrain males’ potential reproductive rate, and females vary substantially in their ability to produce successful offspring. We show that, consistent with predictions, competitive rams focus their mating activity and siring success towards heavier females with higher inclusive fitness. To our knowledge, this is the first time that male mate choice has been identified and shown to lead to assortative patterns of parentage in a natural mammalian system, and occurs despite fierce male–male competition for mates. An additional consequence of assortative mating in this population is that lighter females experience a series of unstable consorts with less adept rams, and hence are mated by a greater number of males during their oestrus. We have thus also identified a novel male-driven mechanism that generates variation in female promiscuity, which suggests that the high levels of female promiscuity in this system are not part of an adaptive female tactic to intensify post-copulatory competition between males. PMID:15734690
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Male mate choice influences female promiscuity in Soay sheep.
Preston, B T; Stevenson, I R; Pemberton, J M; Coltman, D W; Wilson, K
2005-02-22
In most animal species, males are predicted to compete for reproductive opportunities, while females are expected to choose between potential mates. However, when males' rate of reproduction is constrained, or females vary widely in 'quality', male mate choice is also predicted to occur. Such conditions exist in the promiscuous mating system of feral Soay sheep on St Kilda, Scotland, where a highly synchronized mating season, intense sperm competition and limitations on sperm production constrain males' potential reproductive rate, and females vary substantially in their ability to produce successful offspring. We show that, consistent with predictions, competitive rams focus their mating activity and siring success towards heavier females with higher inclusive fitness. To our knowledge, this is the first time that male mate choice has been identified and shown to lead to assortative patterns of parentage in a natural mammalian system, and occurs despite fierce male-male competition for mates. An additional consequence of assortative mating in this population is that lighter females experience a series of unstable consorts with less adept rams, and hence are mated by a greater number of males during their oestrus. We have thus also identified a novel male-driven mechanism that generates variation in female promiscuity, which suggests that the high levels of female promiscuity in this system are not part of an adaptive female tactic to intensify post-copulatory competition between males.
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Allen, W R; Wilsher, S
2012-09-01
Although considerable variation in per cycle pregnancy rates exists between Thoroughbred (TB) stallions, there is little information on factors that may influence this figure. To assess the influence of month, mare numbers and mating frequency on the fertility of TB stallions standing on studfarms in East Anglia, England. The daily breeding records of 31 TB stallions mating 3034 mares on 4851 occasions during the 2010 season were surveyed and related to first scan pregnancy rates. The influences of mare book size, month, number of matings per day and mating frequency or abstinence on per mating pregnancy rates were analysed. The overall per mating pregnancy rate for all the stallions was 59.6%, but for individual stallions the figures ranged from 19.0% to 80.1%. The first mating occurred on 9 February and the last on 24 July and the per mating pregnancy rate per month was significantly reduced in June and July. The number of mares mated by individual stallions ranged from 15 to 161, giving a mean overall workload of 160 matings per 100 mares. The per mating pregnancy rate was not related to book size, the number of matings in the season or the mating frequency per day. However, some stallions showed differences in per mating pregnancy rate related to month or the number of ejaculations in the preceding 3 days. The majority of TB stallions are able to maintain good fertility despite large books of mares. However, 5 of the 31 stallions surveyed showed a per mating pregnancy rate of ≤50%. This survey has identified wide differences between the per mating pregnancy rate in TB stallions. Identification of the factors involved through more comprehensive surveys would provide useful information for mare and stallion owners. © 2011 EVJ Ltd.
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Eagly, Alice H; Eastwick, Paul W; Johannesen-Schmidt, Mary
2009-04-01
In two experiments, female and male participants envisioned themselves as a married person with children who is either a homemaker or a provider. Participants who envisioned themselves as a future homemaker regarded a potential mate's provider qualities as more important and homemaker qualities as less important, compared with participants who envisioned themselves as a future provider. Envisioning oneself as a homemaker also shifted preferences toward an older spouse, compared with envisioning oneself as a provider. In the control conditions of the experiments, in which participants freely envisioned their own future marriage, the less provider responsibility anticipated for the wife, the more traditional were mate preferences. These experiments support the social role theory view that the roles anticipated by men and women influence their choice of mates.
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Rearing Temperature Influences Adult Response to Changes in Mating Status
Westerman, Erica; Monteiro, Antónia
2016-01-01
Rearing environment can have an impact on adult behavior, but it is less clear how rearing environment influences adult behavior plasticity. Here we explore the effect of rearing temperature on adult mating behavior plasticity in the butterfly Bicyclus anynana, a species that has evolved two seasonal forms in response to seasonal changes in temperature. These seasonal forms differ in both morphology and behavior. Females are the choosy sex in cohorts reared at warm temperatures (WS butterflies), and males are the choosy sex in cohorts reared at cooler temperatures (DS butterflies). Rearing temperature also influences mating benefits and costs. In DS butterflies, mated females live longer than virgin females, and mated males live shorter than virgin males. No such benefits or costs to mating are present in WS butterflies. Given that choosiness and mating costs are rearing temperature dependent in B. anynana, we hypothesized that temperature may also impact male and female incentives to remate in the event that benefits and costs of second matings are similar to those of first matings. We first examined whether lifespan was affected by number of matings. We found that two matings did not significantly increase lifespan for either WS or DS butterflies relative to single matings. However, both sexes of WS but not DS butterflies experienced decreased longevity when mated to a non-virgin relative to a virgin. We next observed pairs of WS and DS butterflies and documented changes in mating behavior in response to changes in the mating status of their partner. WS but not DS butterflies changed their mating behavior in response to the mating status of their partner. These results suggest that rearing temperature influences adult mating behavior plasticity in B. anynana. This developmentally controlled behavioral plasticity may be adaptive, as lifespan depends on the partner’s mating status in one seasonal form, but not in the other. PMID:26863319
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Jagadeeshan, Santosh; Shah, Ushma; Chakrabarti, Debarti; Singh, Rama S
2015-01-01
The mating success of larger male Drosophila melanogaster in the laboratory and the wild has been traditionally been explained by female choice, even though the reasons are generally hard to reconcile. Female choice can explain this success by virtue of females taking less time to mate with preferred males, but so can the more aggressive or persistent courtships efforts of large males. Since mating is a negotiation between the two sexes, the behaviors of both are likely to interact and influence mating outcomes. Using a series of assays, we explored these negotiations by testing for the relative influence of male behaviors and its effect on influencing female courtship arousal threshold, which is the time taken for females to accept copulation. Our results show that large males indeed have higher copulation success compared to smaller males. Competition between two males or an increasing number of males had no influence on female sexual arousal threshold;-females therefore may have a relatively fixed 'arousal threshold' that must be reached before they are ready to mate, and larger males appear to be able to manipulate this threshold sooner. On the other hand, the females' physiological and behavioral state drastically influences mating; once females have crossed the courtship arousal threshold they take less time to mate and mate indiscriminately with large and small males. Mating quicker with larger males may be misconstrued to be due to female choice; our results suggest that the mating advantage of larger males may be more a result of heightened male activity and relatively less of female choice. Body size per se may not be a trait under selection by female choice, but size likely amplifies male activity and signal outputs in courtship, allowing them to influence female arousal threshold faster.
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Little, A C; Burt, D M; Penton-Voak, I S; Perrett, D I
2001-01-01
Exaggerated sexual dimorphism and symmetry in human faces have both been linked to potential 'good-gene' benefits and have also been found to influence the attractiveness of male faces. The current study explores how female self-rated attractiveness influences male face preference in females using faces manipulated with computer graphics. The study demonstrates that there is a relatively increased preference for masculinity and an increased preference for symmetry for women who regard themselves as attractive. This finding may reflect a condition-dependent mating strategy analogous to behaviours found in other species. The absence of a preference for proposed markers of good genes may be adaptive in women of low mate value to avoid the costs of decreased parental investment from the owners of such characteristics. PMID:12123296
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Environmental Influences on Mate Preferences as Assessed by a Scenario Manipulation Experiment
Marzoli, Daniele; Moretto, Francesco; Monti, Aura; Tocci, Ornella; Roberts, S. Craig; Tommasi, Luca
2013-01-01
Many evolutionary psychology studies have addressed the topic of mate preferences, focusing particularly on gender and cultural differences. However, the extent to which situational and environmental variables might affect mate preferences has been comparatively neglected. We tested 288 participants in order to investigate the perceived relative importance of six traits of an ideal partner (wealth, dominance, intelligence, height, kindness, attractiveness) under four different hypothetical scenarios (status quo/nowadays, violence/post-nuclear, poverty/resource exhaustion, prosperity/global well-being). An equal number of participants (36 women, 36 men) was allotted to each scenario; each was asked to allocate 120 points across the six traits according to their perceived value. Overall, intelligence was the trait to which participants assigned most importance, followed by kindness and attractiveness, and then by wealth, dominance and height. Men appraised attractiveness as more valuable than women. Scenario strongly influenced the relative importance attributed to traits, the main finding being that wealth and dominance were more valued in the poverty and post-nuclear scenarios, respectively, compared to the other scenarios. Scenario manipulation generally had similar effects in both sexes, but women appeared particularly prone to trade off other traits for dominance in the violence scenario, and men particularly prone to trade off other traits for wealth in the poverty scenario. Our results are in line with other correlational studies of situational variables and mate preferences, and represent strong evidence of a causal relationship of environmental factors on specific mate preferences, corroborating the notion of an evolved plasticity to current ecological conditions. A control experiment seems to suggest that our scenarios can be considered as realistic descriptions of the intended ecological conditions. PMID:24069291
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Gering, Eben J
2017-05-01
Biologists are still discovering diverse and powerful ways sexual conflicts shape biodiversity. The present study examines how the proportion of females in a population that exhibit male mimicry, a mating resistance trait, influences conspecific males' behavior, condition, and survival. Like most female-polymorphic damselflies, Ischnura ramburii harbors both "andromorph" females, which closely resemble males, and sexually dimorphic "gynomorph" counterparts. There is evidence that male mimicry helps andromorphs evade detection and harassment, but males can also learn to target locally prevalent morph(s) via prior mate encounters. I hypothesized that the presence of male mimics could therefore predispose males to mate recognition errors, and thereby increase rates of costly male-male interactions. Consistent with this hypothesis, male-male interaction rates were highest in mesocosms containing more andromorph (vs. gynomorph) females. Males in andromorph-biased mesocosms also had lower final body mass and higher mortality than males assigned to gynomorph-majority treatments. Male survival and body mass were each negatively affected by mesocosm density, and mortality data revealed a marginally significant interaction between andromorph frequency and population density. These findings suggest that, under sufficiently crowded conditions, female mating resistance traits such as male mimicry could have pronounced indirect effects on male behavior, condition, and survival. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.
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Same-Sex Gaze Attraction Influences Mate-Choice Copying in Humans
Yorzinski, Jessica L.; Platt, Michael L.
2010-01-01
Mate-choice copying occurs when animals rely on the mating choices of others to inform their own mating decisions. The proximate mechanisms underlying mate-choice copying remain unknown. To address this question, we tracked the gaze of men and women as they viewed a series of photographs in which a potential mate was pictured beside an opposite-sex partner; the participants then indicated their willingness to engage in a long-term relationship with each potential mate. We found that both men and women expressed more interest in engaging in a relationship with a potential mate if that mate was paired with an attractive partner. Men and women's attention to partners varied with partner attractiveness and this gaze attraction influenced their subsequent mate choices. These results highlight the prevalence of non-independent mate choice in humans and implicate social attention and reward circuitry in these decisions. PMID:20161739
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Sex-Linked Mating Strategies Diverge with a Manipulation of Genital Salience
Fetterman, Adam K.; Kruger, Nicole N.; Robinson, Michael D.
2014-01-01
Trivers (1972) proposed that evolutionary factors should favor divergent mating strategies for males versus females. Such differences may be less pronounced among human beings than other animals and social norms and sex roles are also pertinent influences. The present experiment (N = 133 college undergraduates, 74 female) sought to bypass some of these other influences. Participants were randomly assigned to a condition designed to increase attention to the genital region (a downward pointing arrow) or not (an upward pointing arrow). They then reported on their interest in short-term (e.g., a one-night stand) and long-term (e.g., a potential marital partner) mating opportunities. A theory-consistent three-way interaction occurred such that the genital salience manipulation primed a shorter-term reproductive strategy among men and a longer-term reproductive strategy among women. The results provide unique support for evolution-linked ideas about sex differences in the form of a role for bodily attention. PMID:25663723
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Female mating preferences determine system-level evolution in a gene network model.
Fierst, Janna L
2013-06-01
Environmental patterns of directional, stabilizing and fluctuating selection can influence the evolution of system-level properties like evolvability and mutational robustness. Intersexual selection produces strong phenotypic selection and these dynamics may also affect the response to mutation and the potential for future adaptation. In order to to assess the influence of mating preferences on these evolutionary properties, I modeled a male trait and female preference determined by separate gene regulatory networks. I studied three sexual selection scenarios: sexual conflict, a Gaussian model of the Fisher process described in Lande (in Proc Natl Acad Sci 78(6):3721-3725, 1981) and a good genes model in which the male trait signalled his mutational condition. I measured the effects these mating preferences had on the potential for traits and preferences to evolve towards new states, and mutational robustness of both the phenotype and the individual's overall viability. All types of sexual selection increased male phenotypic robustness relative to a randomly mating population. The Fisher model also reduced male evolvability and mutational robustness for viability. Under good genes sexual selection, males evolved an increased mutational robustness for viability. Females choosing their mates is a scenario that is sufficient to create selective forces that impact genetic evolution and shape the evolutionary response to mutation and environmental selection. These dynamics will inevitably develop in any population where sexual selection is operating, and affect the potential for future adaptation.
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Rios-Cardenas, Oscar; Brewer, Jason; Morris, Molly R
2013-01-01
The differential allocation hypothesis predicts that reproductive investment will be influenced by mate attractiveness, given a cost to reproduction and a tradeoff between current and future reproduction. We tested the differential allocation hypothesis in the swordtail fish Xiphophorus multilineatus, where males have genetically influenced (patroclinous inheritance) alternative mating tactics (ARTs) maintained by a tradeoff between being more attractive to females (mature later as larger courting males) and a higher probability of reaching sexual maturity (mature earlier as smaller sneaker males). Males in X. multilineatus do not provide parental care or other resources to the offspring. Allelic variation and copy number of the Mc4R gene on the Y-chromosome influences the size differences between males, however there is no variation in this gene on the X-chromosome. Therefore, to determine if mothers invested more in offspring of the larger courter males, we examined age to sexual maturity for daughters. We confirmed a tradeoff between number of offspring and female offspring's age to sexual maturity, corroborating that there is a cost to reproduction. In addition, the ART of their fathers significantly influenced the age at which daughters reached sexual maturity, suggesting increased maternal investment to daughters of courter males. The differential allocation we detected was influenced by how long the wild-caught mother had been in the laboratory, as there was a brood order by father genotype (ART) interaction. These results suggest that females can adjust their reproductive investment strategy, and that differential allocation is context specific. We hypothesize that one of two aspects of laboratory conditions produced this shift: increased female condition due to higher quality diet, and/or assessment of future mating opportunities due to isolation from males.
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Rios-Cardenas, Oscar; Brewer, Jason; Morris, Molly R.
2013-01-01
The differential allocation hypothesis predicts that reproductive investment will be influenced by mate attractiveness, given a cost to reproduction and a tradeoff between current and future reproduction. We tested the differential allocation hypothesis in the swordtail fish Xiphophorus multilineatus, where males have genetically influenced (patroclinous inheritance) alternative mating tactics (ARTs) maintained by a tradeoff between being more attractive to females (mature later as larger courting males) and a higher probability of reaching sexual maturity (mature earlier as smaller sneaker males). Males in X. multilineatus do not provide parental care or other resources to the offspring. Allelic variation and copy number of the Mc4R gene on the Y-chromosome influences the size differences between males, however there is no variation in this gene on the X-chromosome. Therefore, to determine if mothers invested more in offspring of the larger courter males, we examined age to sexual maturity for daughters. We confirmed a tradeoff between number of offspring and female offspring’s age to sexual maturity, corroborating that there is a cost to reproduction. In addition, the ART of their fathers significantly influenced the age at which daughters reached sexual maturity, suggesting increased maternal investment to daughters of courter males. The differential allocation we detected was influenced by how long the wild-caught mother had been in the laboratory, as there was a brood order by father genotype (ART) interaction. These results suggest that females can adjust their reproductive investment strategy, and that differential allocation is context specific. We hypothesize that one of two aspects of laboratory conditions produced this shift: increased female condition due to higher quality diet, and/or assessment of future mating opportunities due to isolation from males. PMID:24349348
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NASA Astrophysics Data System (ADS)
Noguera, José C.; Metcalfe, Neil B.; Monaghan, Pat
2017-12-01
Poor early-life nutrition could reduce adult reproductive success by negatively affecting traits linked to sexual attractiveness such as song complexity. If so, this might favor strategic mate choice, allowing males with less complex songs to tailor their mating tactics to maximize the reproductive benefits. However, this possibility has been ignored in theoretical and empirical studies. By manipulating the micronutrient content of the diet (e.g., low or high) during the postnatal period of male zebra finches, we show for the first time (1) that males reared on a poor (low) micronutrient diet had less complex songs as adults; (2) that these males, in contrast to the high micronutrient diet group, were more selective in their mating strategies, discriminating against those females most likely to reduce their clutch size when paired with males having less complex songs; and (3) that by following different mating strategies, males reared on the contrasting diets obtained similar reproductive benefits. These results suggest that early-life dietary conditions can induce multiple and long-lasting effects on male and female reproductive traits. Moreover, the results seem to reflect a previously unreported case of adaptive plasticity in mate choice in response to a nutritionally mediated reduction in sexual attractiveness.
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Svensson, Glenn P; Ryne, Camilla; Löfstedt, Christer
2002-07-01
The short-term evolutionary effect of pheromone-based mating disruption on the mating ability of the Indian meal moth, Plodia interpunctella, was investigated. Three independent selection lines were established, and the mating ability of moths in plastic tents treated with high doses of pheromone and in control tents was compared for two consecutive generations. In addition, the heritability of the sex pheromone blend, measured as the ratio of two major pheromone components (Z,E)-9,12-tetradecadienyl acetate and (Z,E)-9,12-tetradecadienol, was estimated. Based on a mother-daughter regression analysis including 21 families, the heritability of the pheromone blend was 0.65 +/- 0.14, indicating a potential for evolutionary change of the character. However, no increase in mating ability of females in pheromone-treated tents or alteration of the pheromone blend was observed in any selection line when compared with control lines, indicating no or weak selection on the pheromone blend as well as other traits influencing mating ability of this species under the created mating disruption conditions. Factors contributing to the lack of selection effects are discussed.
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Storz, J F; Bhat, H R; Kunz, T H
2001-06-01
Variance in reproductive success is a primary determinant of genetically effective population size (Ne), and thus has important implications for the role of genetic drift in the evolutionary dynamics of animal taxa characterized by polygynous mating systems. Here we report the results of a study designed to test the hypothesis that polygynous mating results in significantly reduced Ne in an age-structured population. This hypothesis was tested in a natural population of a harem-forming fruit bat, Cynopterus sphinx (Chiroptera: Pteropodidae), in western India. The influence of the mating system on the ratio of variance Ne to adult census number (N) was assessed using a mathematical model designed for age-structured populations that incorporated demographic and genetic data. Male mating success was assessed by means of direct and indirect paternity analysis using 10-locus microsatellite genotypes of adults and progeny from two consecutive breeding periods (n = 431 individually marked bats). Combined results from both analyses were used to infer the effective number of male parents in each breeding period. The relative proportion of successfully reproducing males and the size distribution of paternal sibships comprising each offspring cohort revealed an extremely high within-season variance in male mating success (up to 9.2 times higher than Poisson expectation). The resultant estimate of Ne/N for the C. sphinx study population was 0.42. As a result of polygynous mating, the predicted rate of drift (1/2Ne per generation) was 17.6% higher than expected from a Poisson distribution of male mating success. However, the estimated Ne/N was well within the 0.25-0.75 range expected for age-structured populations under normal demographic conditions. The life-history schedule of C. sphinx is characterized by a disproportionately short sexual maturation period scaled to adult life span. Consequently, the influence of polygynous mating on Ne/N is mitigated by the extensive overlap of generations. In C. sphinx, turnover of breeding males between seasons ensures a broader sampling of the adult male gamete pool than expected from the variance in mating success within a single breeding period.
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ERIC Educational Resources Information Center
Gibson-Bilton, Joya
2009-01-01
The purpose of this study was twofold. First, this study examined the influence of African American females' level of self-esteem on the mate-selection process. Secondly, this study was concerned with the influence of the level of self-esteem of African American females on valuing the mate-selection characteristics of interpersonal skills,…
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Mechanisms of sleep plasticity due to sexual experience in Drosophila melanogaster.
Dove, Abigail E; Cook, Brianne L; Irgebay, Zhazira; Vecsey, Christopher G
2017-10-15
Sleep can be altered by an organism's previous experience. For instance, female Drosophila melanogaster experience a post-mating reduction in daytime sleep that is purportedly mediated by sex peptide (SP), one of many seminal fluid proteins (SFPs) transferred from male to female during mating. In the present study, we first characterized this mating effect on sleep more fully, as it had previously only been tested in young flies under 12h light/12h dark conditions. We found that mating reduced sleep equivalently in 3-day-old or 14-day-old females, and could even occur in females who had been mated previously, suggesting that there is not a developmental critical period for the suppression of sleep by mating. In conditions of constant darkness, circadian rhythms were not affected by prior mating. In either constant darkness or constant light, the sleep reduction due to mating was no longer confined to the subjective day but could be observed throughout the 24-hour period. This suggests that the endogenous clock may dictate the timing of when the mating effect on sleep is expressed. We recently reported that genetic elimination of SP only partially blocked the post-mating female siesta sleep reduction, suggesting that the effect was unlikely to be governed solely by SP. We found here that the daytime sleep reduction was also reduced but not eliminated in females mated to mutant males lacking the vast majority of SFPs. This suggested that SFPs other than SP play a minimal role in the mating effect on sleep, and that additional non-SFP signals from the male might be involved. Males lacking sperm were able to induce a normal initial mating effect on female sleep, although the effect declined more rapidly in these females. This result indicated that neither the presence of sperm within the female reproductive tract nor female impregnation are required for the initial mating effect on sleep to occur, although sperm may serve to prolong the effect. Finally, we tested for contributions from other aspects of the mating experience. NorpA and eya2 mutants with disrupted vision showed normal mating effects on sleep. By separating males from females with a mesh, we found that visual and olfactory stimuli from male exposure, in the absence of physical contact, could not replicate the mating effect. Further, in ken/barbie male flies lacking external genitalia, courtship and physical contact without ejaculation were also unable to replicate the mating effect. These findings confirmed that the influence of mating on sleep does in fact require male/female contact including copulation, but may not be mediated exclusively by SP transfer. Copyright © 2017 Elsevier Inc. All rights reserved.
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Effect of Temperature on Galling Behavior of SS 316, 316 L and 416 Under Self-Mated Condition
NASA Astrophysics Data System (ADS)
Harsha, A. P.; Limaye, P. K.; Tyagi, Rajnesh; Gupta, Ankit
2016-11-01
Galling behavior of three different stainless steels (SS 316, 316 L and 416) was evaluated at room temperature and 300 °C under a self-mated condition. An indigenously fabricated galling tester was used to evaluate the galling performance of mated materials as per ASTM G196-08 standard. The variation in frictional torque was recorded online during the test to assess the onset of galling. The galling50 (G50) stress value was used to compare the galling resistance of a combination of materials, and the results indicate a significant influence of temperature on the galling resistance of the materials tested. This has been attributed to the decrease in hardness and yield strength at elevated temperature which results in softening of the steel and limits its ability to resist severe deformation. Scanning electron micrographs of the galled surface reflected a severe plastic deformation in sliding direction, and a typical adhesive wear mechanism is prevalent during the galling process.
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Bates, M L Shawn; Emery, Michael A; Wellman, Paul J; Eitan, Shoshana
2014-09-01
Adolescent opioid abuse is on the rise, and current treatments are not effective in reducing rates of relapse. Our previous studies demonstrated that social housing conditions alter the acquisition rate of morphine conditioned place preference (CPP) in adolescent mice. Specifically, the acquisition rate of morphine CPP is slower in morphine-treated animals housed with drug-naïve animals. Thus, here we tested the effect of social housing conditions on the development of morphine dependence and the extinction rate of an acquired morphine CPP. Adolescent male mice were group-housed in one of two housing conditions. They were injected for 6 days (PND 28-33) with 20 mg/kg morphine. Morphine only mice are animals where all four mice in the cage received morphine. Morphine cage-mate mice are morphine-injected animals housed with drug-naïve animals. Mice were individually tested for spontaneous withdrawal signs by quantifying jumping behavior 4, 8, 24, and 48 h after the final morphine injection. Then, mice were conditioned to acquire morphine CPP and were tested for the rate of extinction. Morphine cage-mates express less jumping behavior during morphine withdrawal as compared to morphine only mice. As expected, morphine cage-mate animals acquired morphine CPP more slowly than the morphine only animals. Additionally, morphine cage-mates extinguished morphine CPP more readily than morphine only mice. Social housing conditions modulate morphine dependence and the extinction rate of morphine CPP. Extinction testing is relevant to human addiction because rehabilitations like extinction therapy may be used to aid human addicts in maintaining abstinence from drug use. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
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Attractants for ACP trapping technology: Challenges, status, and opportunities
USDA-ARS?s Scientific Manuscript database
Psyllid host searching behavior is complex and sophisticated. It can be influenced by host species, growth stage, and physiological condition, psyllid gender and mating status, behavioral plasticity, usurpation by phytopathogens of host aromas, and psyllid-induced emission of foliar volatiles. Asian...
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Bejanyan, Kathrine; Marshall, Tara C; Ferenczi, Nelli
2015-01-01
In collectivist cultures, families tend to be characterized by respect for parental authority and strong, interdependent ties. Do these aspects of collectivism exert countervailing pressures on mate choices and relationship quality? In the present research, we found that collectivism was associated with greater acceptance of parental influence over mate choice, thereby driving relationship commitment down (Studies 1 and 2), but collectivism was also associated with stronger family ties (referred to as family allocentrism), which drove commitment up (Study 2). Along similar lines, Study 1 found that collectivists' greater acceptance of parental influence on mate choice contributed to their reduced relationship passion, whereas Study 2 found that their greater family allocentrism may have enhanced their passion. Study 2 also revealed that collectivists may have reported a smaller discrepancy between their own preferences for mates high in warmth and trustworthiness and their perception of their parents' preferences for these qualities because of their stronger family allocentrism. However, their higher tolerance of parental influence may have also contributed to a smaller discrepancy in their mate preferences versus their perceptions of their parents' preferences for qualities signifying status and resources. Implications for the roles of collectivism, parental influence, and family allocentrism in relationship quality and mate selection will be discussed.
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Bejanyan, Kathrine; Marshall, Tara C.; Ferenczi, Nelli
2015-01-01
In collectivist cultures, families tend to be characterized by respect for parental authority and strong, interdependent ties. Do these aspects of collectivism exert countervailing pressures on mate choices and relationship quality? In the present research, we found that collectivism was associated with greater acceptance of parental influence over mate choice, thereby driving relationship commitment down (Studies 1 and 2), but collectivism was also associated with stronger family ties (referred to as family allocentrism), which drove commitment up (Study 2). Along similar lines, Study 1 found that collectivists’ greater acceptance of parental influence on mate choice contributed to their reduced relationship passion, whereas Study 2 found that their greater family allocentrism may have enhanced their passion. Study 2 also revealed that collectivists may have reported a smaller discrepancy between their own preferences for mates high in warmth and trustworthiness and their perception of their parents’ preferences for these qualities because of their stronger family allocentrism. However, their higher tolerance of parental influence may have also contributed to a smaller discrepancy in their mate preferences versus their perceptions of their parents’ preferences for qualities signifying status and resources. Implications for the roles of collectivism, parental influence, and family allocentrism in relationship quality and mate selection will be discussed. PMID:25719563
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No evidence of inbreeding avoidance in a polygynous ungulate: the reindeer (Rangifer tarandus).
Holand, Oystein; Askim, Kjartan R; Røed, Knut H; Weladji, Robert B; Gjøstein, Hallvard; Nieminen, Mauri
2007-02-22
In polygynous species, mate choice is an integrated part of sexual selection. However, whether mate choice occurs independently of the genetic relatedness among mating pairs has received little attention, although inbreeding may have fitness consequences. We studied whether genetic relatedness influenced females' choice of partner in a highly polygynous ungulate--the reindeer (Rangifer tarandus)--in an experimental herd during two consecutive rutting seasons; the herd consisting of 75 females in 1999 and 74 females in 2000 was exposed to three 4.5-year-old adults and three 1.5-year-old young males, respectively. The females' distribution during peak rut was not influenced by their genetic relatedness with the dominant males of the mating groups. Further, genetic relatedness did not influence the actual choice of mating partner. We conclude that inbreeding avoidance through mating group choice as well as choice of mating partner, two interconnected processes of female mate choice operating at two different scales in space and time, in such a highly female-biased reindeer populations with low level of inbreeding may not occur.
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Bates, M L S; Emery, M A; Wellman, P J; Eitan, S
2016-07-01
Chronic opioid treatment is complicated by the development of tolerance and hyperalgesia. Social environment alters both opioid-induced behaviours and nociceptive mechanisms. Our previous studies demonstrated that, in adolescent rodents, the susceptibility to acquire opioid dependence and reward is dependent on the nature of social housing conditions. Specifically, our previous studies demonstrate that housing morphine-treated mice with drug-naïve animals mitigates the abuse liability of opioids. Thus, this study tested the effect of social housing conditions on the development of adaptive processes to morphine antinociception. Adolescent males were group-housed in different conditions. In the mixed treatment condition, mice treated with 20 mg/kg morphine (i.e. 'morphine cage-mates') and saline (i.e. 'saline cage-mates') were housed together. In the separated treatment conditions, all mice in the cage received morphine (i.e. 'morphine only') or saline (i.e. 'saline only'). All animals were tested for baseline pain sensitivity and for the response to morphine in the tail withdrawal, hot plate, acetone and von Frey filament tests, during and after discontinuation of opioid treatment. Both morphine cage-mate and morphine only animals developed antinociceptive tolerance. However, this effect was more robust and persistent in the morphine only group. Notably, morphine only animals, but not morphine cage-mates, developed opioid-induced hyperalgesia. This study demonstrates that housing morphine-treated mice with drug-naïve animals mitigates the development of opioid-induced hyperalgesia and antinociceptive tolerance. Thus, this study indicates that social environment influences the effectiveness of opioid pain management. © 2016 European Pain Federation - EFIC®
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De Jong, TR; Harris, BN; Perea-Rodriguez, JP; Saltzman, W
2013-01-01
Social environment and parental state affect stress responses in mammals, but their impact may depend on the social and reproductive strategy of the species. The influences of cohabitation with a male or female conspecific, and the birth of offspring, on the physiological and endocrine responses to chronic variable stress were studied in the monogamous and biparental California mouse (Peromyscus californicus). Adult male California mice were housed either with a male cage mate (virgin males, VM), a female cage mate (pair-bonded males, PBM), or a female cage mate and their first newborn litter (new fathers, NF). VM, PBM and NF underwent a 7-day chronic variable stress paradigm (CVS, three stressors per day at semi-random times, n=7-8 per housing condition). Compared to control males (CON, n=6-7 per housing condition), CVS caused loss of body mass, increased basal plasma corticosterone concentrations, and increased basal expression of arginine vasopressin (AVP) mRNA in the paraventricular nucleus of the hypothalamus (PVN). These effects were independent of housing condition. Neither CVS nor housing condition altered novel-stressor-induced corticosterone release, spleen or testis mass, or basal expression of corticotropin-releasing hormone (CRH) mRNA in the PVN. Although CVS appeared to increase adrenal mass and reduce thymus mass specifically in NF, these effects were explained by the lower adrenal mass and higher thymus mass of NF compared to PBM and VM under control conditions. These results suggest that neither engaging in a pair bond nor becoming a father attenuates typical responses to CVS, but that fatherhood may provide a buffer against transient mild stressors (i.e., weighing and blood sampling in the control groups) in this monogamous and biparental rodent. PMID:23582312
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Hockley, F A; Wilson, C A M E; Graham, N; Cable, J
2014-01-01
Group living in fish can provide benefits of protection from predators and some parasites, more efficient foraging for food, increased mating opportunities and enhanced energetic benefit when swimming. For riverine species, shoaling behaviour can be influenced by various environmental stressors, yet little is known how flow rate might influence the shoaling of diseased fish shoals. In view of the increasingly unpredictable flow rates in streams and rivers, this study aimed to assess the combined effect of flow condition and parasitism on the shoaling behaviour of a model fish species. Shoal size, shoal cohesion and time spent shoaling of female guppies Poecilia reticulata were compared when infected with the directly transmitted ectoparasite Gyrodactylus turnbulli under flow and static conditions. Flow condition was an important factor in influencing shoaling behaviour of guppies with the fish forming larger shoals in the absence of flow. When a shoal member was infected with G. turnbulli , shoal cohesion was reduced, but the magnitude of this effect was dependent on flow condition. In both flow and static conditions, bigger fish formed larger shoals than smaller counterparts. Future changes to stream hydrology with more frequent flooding and drought events will affect the shoaling tendency of fish. During high-flow events, diseased fish may not be able to keep up with shoal mates and therefore have a higher risk of predation. Additionally, these findings may be important for aquaria and farmed species where an increase in flow rate may reduce aggregation in fish.
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Li, Weijian; Zhang, Yuchi; Li, Fengying; Li, Xinyu; Li, Ping; Jia, Xiaoyu; Chen, Haide; Ji, Haojie
2015-01-01
Although a growing number of empirical studies have revealed that activating mate-related motives might exert a specific set of consequences for human cognition and behaviors, such as attention and memory, little is known about whether mate-related motives affect self-regulated learning. The present study examined the effects of mate-related motives (mate-search and mate-guarding) on study-time allocation to faces varying in attractiveness. In two experiments, participants in mate-related priming conditions (Experiment 1: mate-search; Experiment 2: mate-guarding) or control conditions studied 20 female faces (10 highly attractive, 10 less attractive) during a self-paced study task, and then were given a yes/no face recognition task. The finding of Experiment 1 showed that activating a mate-search motive led the male participants to allocate more time to highly attractive female faces (i.e., perceived potential mates) than to less attractive ones. In Experiment 2, female participants in the mate-guarding priming condition spent more time studying highly attractive female faces (i.e., perceived potential rivals) than less attractive ones, compared to participants in the control condition. These findings illustrate the highly specific consequences of mate-related motives on study-time allocation, and highlight the value of exploring human cognition and motivation within evolutionary and self-regulated learning frameworks.
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Li, Fengying; Li, Xinyu; Li, Ping; Jia, Xiaoyu; Chen, Haide; Ji, Haojie
2015-01-01
Although a growing number of empirical studies have revealed that activating mate-related motives might exert a specific set of consequences for human cognition and behaviors, such as attention and memory, little is known about whether mate-related motives affect self-regulated learning. The present study examined the effects of mate-related motives (mate-search and mate-guarding) on study-time allocation to faces varying in attractiveness. In two experiments, participants in mate-related priming conditions (Experiment 1: mate-search; Experiment 2: mate-guarding) or control conditions studied 20 female faces (10 highly attractive, 10 less attractive) during a self-paced study task, and then were given a yes/no face recognition task. The finding of Experiment 1 showed that activating a mate-search motive led the male participants to allocate more time to highly attractive female faces (i.e., perceived potential mates) than to less attractive ones. In Experiment 2, female participants in the mate-guarding priming condition spent more time studying highly attractive female faces (i.e., perceived potential rivals) than less attractive ones, compared to participants in the control condition. These findings illustrate the highly specific consequences of mate-related motives on study-time allocation, and highlight the value of exploring human cognition and motivation within evolutionary and self-regulated learning frameworks. PMID:26121131
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Deng, Yan; Zheng, Yong
2015-01-26
Studies of humans and non-human animals indicate that females tend to change the likelihood of choosing a potential mate based on the decisions of other females; this is known as mate-choice copying. In a sample of both single and coupled women, we examined the influence of other women's (model) mate-choice decisions, including mate acceptance and mate rejection, on participants' attractiveness ratings of men (target) and willingness of mate selection. We also examined whether different types of relationships between the target men and the model women affected mate-choice copying. We found that both the single and coupled women showed mate-choice copying, but their response patterns differed. The significant effects for single women were dependent on a decrease in attractiveness ratings when they perceived the models' mate rejection. However, the significant findings for coupled women relied on an increase in attractiveness ratings when they observed the models' mate acceptance. Furthermore, the relationship status between the target men and the model women affected the magnitude of mate-choice copying effects for the single women. Specifically, they showed less mate-choice copying when the targets and models were in a committed romantic relationship than when in a temporary relationship.
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Good genes, complementary genes and human mate preferences.
Roberts, S Craig; Little, Anthony C
2008-03-01
The past decade has witnessed a rapidly growing interest in the biological basis of human mate choice. Here we review recent studies that demonstrate preferences for traits which might reveal genetic quality to prospective mates, with potential but still largely unknown influence on offspring fitness. These include studies assessing visual, olfactory and auditory preferences for potential good-gene indicator traits, such as dominance or bilateral symmetry. Individual differences in these robust preferences mainly arise through within and between individual variation in condition and reproductive status. Another set of studies have revealed preferences for traits indicating complementary genes, focussing on discrimination of dissimilarity at genes in the major histocompatibility complex (MHC). As in animal studies, we are only just beginning to understand how preferences for specific traits vary and inter-relate, how consideration of good and compatible genes can lead to substantial variability in individual mate choice decisions and how preferences expressed in one sensory modality may reflect those in another. Humans may be an ideal model species in which to explore these interesting complexities.
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Good genes, complementary genes and human mate preferences.
Roberts, S Craig; Little, Anthony C
2008-09-01
The past decade has witnessed a rapidly growing interest in the biological basis of human mate choice. Here we review recent studies that demonstrate preferences for traits which might reveal genetic quality to prospective mates, with potential but still largely unknown influence on offspring fitness. These include studies assessing visual, olfactory and auditory preferences for potential good-gene indicator traits, such as dominance or bilateral symmetry. Individual differences in these robust preferences mainly arise through within and between individual variation in condition and reproductive status. Another set of studies have revealed preferences for traits indicating complementary genes, focussing on discrimination of dissimilarity at genes in the major histocompatibility complex (MHC). As in animal studies, we are only just beginning to understand how preferences for specific traits vary and inter-relate, how consideration of good and compatible genes can lead to substantial variability in individual mate choice decisions and how preferences expressed in one sensory modality may reflect those in another. Humans may be an ideal model species in which to explore these interesting complexities.
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The causes of variation in the presence of genetic covariance between sexual traits and preferences.
Fowler-Finn, Kasey D; Rodríguez, Rafael L
2016-05-01
Mating traits and mate preferences often show patterns of tight correspondence across populations and species. These patterns of apparent coevolution may result from a genetic association between traits and preferences (i.e. trait-preference genetic covariance). We review the literature on trait-preference covariance to determine its prevalence and potential biological relevance. Of the 43 studies we identified, a surprising 63% detected covariance. We test multiple hypotheses for factors that may influence the likelihood of detecting this covariance. The main predictor was the presence of genetic variation in mate preferences, which is one of the three main conditions required for the establishment of covariance. In fact, 89% of the nine studies where heritability of preference was high detected covariance. Variables pertaining to the experimental methods and type of traits involved in different studies did not greatly influence the detection of trait-preference covariance. Trait-preference genetic covariance appears to be widespread and therefore represents an important and currently underappreciated factor in the coevolution of traits and preferences. © 2015 Cambridge Philosophical Society.
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Within-season variability of fighting behaviour in an Australian alpine grasshopper
Muschett, Giselle; Umbers, Kate D. L.; Herberstein, Marie E.
2017-01-01
Throughout the breeding season, changing environmental and biological conditions can lead to variation in the reproductive landscape of many species. In alpine environments temperature is a key driver of behaviour for small ectotherms such as insects, but variable biotic factors such as mate quality and availability can also influence behaviour. Kosicuscola tristis is a small semelparous grasshopper of the Australian alpine region. In a rare behaviour among grasshoppers, K. tristis males engage in vigorous fights over access to females, involving mandible displays, kicking, biting and grappling. In this study we describe the variation in fighting behaviour of K. tristis throughout the breeding season and test several hypotheses related to temperature, body size, mating behaviour, and female quality. We show that K. tristis males are more aggressive toward each other at the end of the breeding season than at the beginning. This increased aggression is associated with decreased daily average temperatures (from ~20°C to ~9°C), decreased mating activity, increased female fecundity, and an unexpected trend toward an increase in female-to-male aggression. These results suggest that K. tristis is likely under increased selective pressure to time key life cycle events with favourable biological and climatic conditions. The stochastic nature of alpine environments combined with a relatively short life span and breeding season, as well as limited mating opportunities toward the end of the season may have contributed to the evolution of this extraordinary mating system. PMID:28403243
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Social transmission of Pavlovian fear: fear-conditioning by-proxy in related female rats.
Jones, Carolyn E; Riha, Penny D; Gore, Andrea C; Monfils, Marie-H
2014-05-01
Pairing a previously neutral conditioned stimulus (CS; e.g., a tone) to an aversive unconditioned stimulus (US; e.g., a foot-shock) leads to associative learning such that the tone alone will elicit a conditioned response (e.g., freezing). Individuals can also acquire fear from a social context, such as through observing the fear expression of a conspecific. In the current study, we examined the influence of kinship/familiarity on social transmission of fear in female rats. Rats were housed in triads with either sisters or non-related females. One rat from each cage was fear conditioned to a tone CS+ shock US. On day two, the conditioned rat was returned to the chamber accompanied by one of her cage mates. Both rats were allowed to behave freely, while the tone was played in the absence of the foot-shock. The previously untrained rat is referred to as the fear-conditioned by-proxy (FCbP) animal, as she would freeze based on observations of her cage-mate's response rather than due to direct personal experience with the foot-shock. The third rat served as a cage-mate control. The third day, long-term memory tests to the CS were performed. Consistent with our previous application of this paradigm in male rats (Bruchey et al. in Behav Brain Res 214(1):80-84, 2010), our results revealed that social interactions between the fear conditioned and FCbP rats on day two contribute to freezing displayed by the FCbP rats on day three. In this experiment, prosocial behavior occurring at the termination of the cue on day two was significantly greater between sisters than their non-sister counterparts, and this behavior resulted in increased freezing on day three. Our results suggest that familiarity and/or kinship influences the social transmission of fear in female rats.
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Nora, Sofia; Aparicio, Abelardo; Albaladejo, Rafael G.
2016-01-01
Anthropogenic habitat deterioration can promote changes in plant mating systems that subsequently may affect progeny performance, thereby conditioning plant recruitment for the next generation. However, very few studies yet tested mating system parameters other than outcrossing rates; and the direct effects of the genetic diversity of the pollen received by maternal plants (i.e. correlated paternity) has often been overlooked. In this study, we investigated the relation between correlated paternity and progeny performance in two common Mediterranean shrubs, Myrtus communis and Pistacia lentiscus. To do so, we collected open-pollinated progeny from selected maternal plants, calculated mating system parameters using microsatellite genotyping and conducted sowing experiments under greenhouse and field conditions. Our results showed that some progeny fitness components were negatively affected by the high correlated paternity of maternal plants. In Myrtus communis, high correlated paternity had a negative effect on the proportion and timing of seedling emergence in the natural field conditions and in the greenhouse sowing experiment, respectively. In Pistacia lentiscus, seedling emergence time under field conditions was also negatively influenced by high correlated paternity and a progeny survival analysis in the field experiment showed greater mortality of seedlings from maternal plants with high correlated paternity. Overall, we found effects of correlated paternity on the progeny performance of Myrtus communis, a self-compatible species. Further, we also detected effects of correlated paternity on the progeny emergence time and survival in Pistacia lentiscus, an obligate outcrossed species. This study represents one of the few existing empirical examples which highlight the influence that correlated paternity may exert on progeny performance in multiple stages during early seedling growth. PMID:27835658
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Nora, Sofia; Aparicio, Abelardo; Albaladejo, Rafael G
2016-01-01
Anthropogenic habitat deterioration can promote changes in plant mating systems that subsequently may affect progeny performance, thereby conditioning plant recruitment for the next generation. However, very few studies yet tested mating system parameters other than outcrossing rates; and the direct effects of the genetic diversity of the pollen received by maternal plants (i.e. correlated paternity) has often been overlooked. In this study, we investigated the relation between correlated paternity and progeny performance in two common Mediterranean shrubs, Myrtus communis and Pistacia lentiscus. To do so, we collected open-pollinated progeny from selected maternal plants, calculated mating system parameters using microsatellite genotyping and conducted sowing experiments under greenhouse and field conditions. Our results showed that some progeny fitness components were negatively affected by the high correlated paternity of maternal plants. In Myrtus communis, high correlated paternity had a negative effect on the proportion and timing of seedling emergence in the natural field conditions and in the greenhouse sowing experiment, respectively. In Pistacia lentiscus, seedling emergence time under field conditions was also negatively influenced by high correlated paternity and a progeny survival analysis in the field experiment showed greater mortality of seedlings from maternal plants with high correlated paternity. Overall, we found effects of correlated paternity on the progeny performance of Myrtus communis, a self-compatible species. Further, we also detected effects of correlated paternity on the progeny emergence time and survival in Pistacia lentiscus, an obligate outcrossed species. This study represents one of the few existing empirical examples which highlight the influence that correlated paternity may exert on progeny performance in multiple stages during early seedling growth.
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From Preferred to Actual Mate Characteristics: The Case of Human Body Shape
Courtiol, Alexandre; Picq, Sandrine; Godelle, Bernard; Raymond, Michel; Ferdy, Jean-Baptiste
2010-01-01
The way individuals pair to produce reproductive units is a major factor determining evolution. This process is complex because it is determined not only by individual mating preferences, but also by numerous other factors such as competition between mates. Consequently, preferred and actual characteristics of mates obtained should differ, but this has rarely been addressed. We simultaneously measured mating preferences for stature, body mass, and body mass index, and recorded corresponding actual partner's characteristics for 116 human couples from France. Results show that preferred and actual partner's characteristics differ for male judges, but not for females. In addition, while the correlation between all preferred and actual partner's characteristics appeared to be weak for female judges, it was strong for males: while men prefer women slimmer than their actual partner, those who prefer the slimmest women also have partners who are slimmer than average. This study therefore suggests that the influences of preferences on pair formation can be sex-specific. It also illustrates that this process can lead to unexpected results on the real influences of mating preferences: traits considered as highly influencing attractiveness do not necessarily have a strong influence on the actual pairing, the reverse being also possible. PMID:20885953
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From preferred to actual mate characteristics: the case of human body shape.
Courtiol, Alexandre; Picq, Sandrine; Godelle, Bernard; Raymond, Michel; Ferdy, Jean-Baptiste
2010-09-27
The way individuals pair to produce reproductive units is a major factor determining evolution. This process is complex because it is determined not only by individual mating preferences, but also by numerous other factors such as competition between mates. Consequently, preferred and actual characteristics of mates obtained should differ, but this has rarely been addressed. We simultaneously measured mating preferences for stature, body mass, and body mass index, and recorded corresponding actual partner's characteristics for 116 human couples from France. Results show that preferred and actual partner's characteristics differ for male judges, but not for females. In addition, while the correlation between all preferred and actual partner's characteristics appeared to be weak for female judges, it was strong for males: while men prefer women slimmer than their actual partner, those who prefer the slimmest women also have partners who are slimmer than average. This study therefore suggests that the influences of preferences on pair formation can be sex-specific. It also illustrates that this process can lead to unexpected results on the real influences of mating preferences: traits considered as highly influencing attractiveness do not necessarily have a strong influence on the actual pairing, the reverse being also possible.
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Commensal Bacteria Aid Mate-selection in the Fruit Fly, Bactrocera dorsalis.
Damodaram, Kamala Jayanthi Pagadala; Ayyasamy, Arthikirubha; Kempraj, Vivek
2016-10-01
Commensal bacteria influence many aspects of an organism's behaviour. However, studies on the influence of commensal bacteria in insect mate-selection are scarce. Here, we present empirical evidence that commensal bacteria mediate mate-selection in the Oriental fruit fly, Bactrocera dorsalis. Male flies were attracted to female flies, but this attraction was abolished when female flies were fed with antibiotics, suggesting the role of the fly's microbiota in mediating mate-selection. We show that male flies were attracted to and ejaculated more sperm into females harbouring the microbiota. Using culturing and 16S rDNA sequencing, we isolated and identified different commensal bacteria, with Klebsiella oxytoca being the most abundant bacterial species. This preliminary study will enhance our understanding of the influence of commensal bacteria on mate-selection behaviour of B. dorsalis and may find use in devising control operations against this devastating pest.
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How multiple mating by females affects sexual selection
Shuster, Stephen M.; Briggs, William R.; Dennis, Patricia A.
2013-01-01
Multiple mating by females is widely thought to encourage post-mating sexual selection and enhance female fitness. We show that whether polyandrous mating has these effects depends on two conditions. Condition 1 is the pattern of sperm utilization by females; specifically, whether, among females, male mating number, m (i.e. the number of times a male mates with one or more females) covaries with male offspring number, o. Polyandrous mating enhances sexual selection only when males who are successful at multiple mating also sire most or all of each of their mates' offspring, i.e. only when Cov♂(m,o), is positive. Condition 2 is the pattern of female reproductive life-history; specifically, whether female mating number, m, covaries with female offspring number, o. Only semelparity does not erode sexual selection, whereas iteroparity (i.e. when Cov♀(m,o), is positive) always increases the variance in offspring numbers among females, which always decreases the intensity of sexual selection on males. To document the covariance between mating number and offspring number for each sex, it is necessary to assign progeny to all parents, as well as identify mating and non-mating individuals. To document significant fitness gains by females through iteroparity, it is necessary to determine the relative magnitudes of male as well as female contributions to the total variance in relative fitness. We show how such data can be collected, how often they are collected, and we explain the circumstances in which selection favouring multiple mating by females can be strong or weak. PMID:23339237
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Mating Goals Moderate Power's Effect on Conspicuous Consumption Among Women.
Zhao, Taiyang; Jin, Xiaotong; Xu, Wei; Zuo, Xiaomeng; Cui, Hongjing
2017-01-01
This study aimed to use evolutionary psychology to explain conspicuous consumption's relationship with mating goals among women. We used experiments to show that power moderates conspicuous consumption's relationship with mating goals among women through an underlying relationship with women's social comparison tendencies. In Study 1, the participants read a passage describing a young woman wearing a coat made by a conspicuous brand (vs. an ordinary brand) who aimed to attract a desired man (vs. aiming to guard against potential competitors' attempts to disrupt her established intimate relationship). Participants in the conspicuous-brand condition were more confident that the young woman would succeed in mate attraction and guarding than participants in the ordinary-brand condition, suggesting the participants believed the conspicuous brands facilitated mate attraction and mate guarding more than ordinary brands. Study 2 manipulated the participants' power states and mating goals and measured participants' social comparison tendencies and conspicuous consumption index values. In the mate-guarding condition, high-power participants showed more inclination toward conspicuous consumption than low-power participants. In the mate-attraction condition, low-power participants showed a greater inclination toward conspicuous consumption than did high-power participants. Comparison orientation also mediated power's effect on conspicuous consumption inclination. The evolutionary psychological basis for the above findings is discussed, and suggestions are offered regarding product marketing.
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Martínez-Guerrero, Lucy J.; Morales, Mark; Ekins, Sean
2016-01-01
Multidrug and toxin extruder (MATE) 1 plays a central role in mediating renal secretion of organic cations, a structurally diverse collection of compounds that includes ∼40% of prescribed drugs. Because inhibition of transport activity of other multidrug transporters, including the organic cation transporter (OCT) 2, is influenced by the structure of the transported substrate, the present study screened over 400 drugs as inhibitors of the MATE1-mediated transport of four structurally distinct organic cation substrates: the commonly used drugs: 1) metformin and 2) cimetidine; and two prototypic cationic substrates, 3) 1-methyl-4-phenylpyridinium (MPP), and 4) the novel fluorescent probe, N,N,N-trimethyl-2-[methyl(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)amino]ethanaminium iodide. Transport was measured in Chinese hamster ovary cells that stably expressed the human ortholog of MATE1. Comparison of the resulting inhibition profiles revealed no systematic influence of substrate structure on inhibitory efficacy. Similarly, IC50 values for 26 structurally diverse compounds revealed no significant influence of substrate structure on the kinetic interaction of inhibitor with MATE1. The IC50 data were used to generate three-dimensional quantitative pharmacophores that identified hydrophobic regions, H-bond acceptor sites, and an ionizable (cationic) feature as key determinants for ligand binding to MATE1. In summary, in contrast to the behavior observed with some other multidrug transporters, including OCT2, the results suggest that substrate identity exerts comparatively little influence on ligand interaction with MATE1. PMID:27418674
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Grob, B; Knapp, L A; Martin, R D; Anzenberger, G
1998-01-01
It has been known for decades that MHC genes play a critical role in the cellular immune response, but only recent research has provided a better understanding of how these molecules might affect mate choice. Original studies in inbred mouse strains revealed that mate choice was influenced by MHC dissimilarity. Detection of MHC differences between individuals in these experiments was related to olfactory cues, primarily in urine. Recent studies in humans have shown an analogous picture of MHC-based mating. Taken together, these findings could support either the hypothesis of MHC-based inbreeding avoidance or the hypothesis of MHC-related avoidance of reproductive failure, since studies in mice, humans and pigtailed macaques have shown that parental sharing of certain MHC alleles correlates with frequent spontaneous abortion or prolonged intergestational intervals. Data from many mammalian species clearly demonstrate that reproductive failure occurs as a result of inbreeding. Therefore, MHC similarity might serve as an indicator of genome-wide relatedness. In contrast, increased fitness due to the presence of individual MHC alleles in a pathogenic environment could explain MHC-based selection of currently good genes. Specifically, the physical condition of long-living animals depends on the ability to respond to immunological challenge and an individual's MHC alleles determine the response, since, unlike the T cell receptors, MHC alleles are not somatically recombined. Therefore, sexual selection of condition-dependent traits during mate choice could be used to select successful MHC alleles, thereby providing offspring with a higher relative immunity in their pathogenic environment.
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Geographical variation in sexual behavior and body traits in a sex role reversed wolf spider
NASA Astrophysics Data System (ADS)
Bollatti, Fedra; Diaz, Virginia Garcia; Peretti, Alfredo V.; Aisenberg, Anita
2017-06-01
Mating partners need to recognize, assess each other, and exchange information through behavioral events that occur before, during, and after mating. Sexual signals, as well as life history traits, are influenced by selective pressures and environmental factors that can vary across distant geographical areas. Allocosa senex is a sand-dwelling wolf spider which constructs burrows along the sandy coasts of Argentina, Brazil, and Uruguay. Females are the mobile sex that searches for males and initiates courtship. They prefer males which construct longer burrows, and males prefer virgin females in good body condition. The objective of this study was to compare sexual behavior patterns, as well as body characteristics and burrow dimensions, between two geographically distant locations of A. senex, one in Uruguay (Uruguayan location) and the other from central Argentina (Argentinean location). We found differences in the number of male abdominal vibrations, male and female touches during mating, and number of erections of male leg spines, which all were higher in matings of Argentinean pairs. On the other hand, male body mass and female body condition were higher in Uruguayan individuals. The wide distribution of A. senex could be determining variations in the biotic and abiotic features that affect the species, generating differences in the strength of selective forces acting on individuals from the two studied locations.
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Filice, David C S; Long, Tristan A F
2017-05-01
Female mate choice is a complex decision-making process that involves many context-dependent factors. In Drosophila melanogaster , a model species for the study of sexual selection, indirect genetic effects (IGEs) of general social interactions can influence female mate choice behaviors, but the potential impacts of IGEs associated with mating experiences are poorly understood. Here, we examined whether the IGEs associated with a previous mating experience had an effect on subsequent female mate choice behaviors and quantified the degree of additive genetic variation associated with this effect. Females from 21 different genetic backgrounds were housed with males from one of two distinct genetic backgrounds for either a short (3 hr) or long (48 hr) exposure period and their subsequent mate choice behaviors were scored. We found that the genetic identity of a previous mate significantly influenced a female's subsequent interest in males and preference of males. Additionally, a hemiclonal analysis revealed significant additive genetic variation associated with experience-dependent mate choice behaviors, indicating a genotype-by-environment interaction for both of these parameters. We discuss the significance of these results with regard to the evolution of plasticity in female mate choice behaviors and the maintenance of variation in harmful male traits.
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Host mating system and the prevalence of a disease in a plant population
Koslow, Jennifer M.; DeAngelis, Donald L.
2006-01-01
A modified susceptible–infected–recovered (SIR) host–pathogen model is used to determine the influence of plant mating system on the outcome of a host–pathogen interaction. Unlike previous models describing how interactions between mating system and pathogen infection affect individual fitness, this model considers the potential consequences of varying mating systems on the prevalence of resistance alleles and disease within the population. If a single allele for disease resistance is sufficient to confer complete resistance in an individual and if both homozygote and heterozygote resistant individuals have the same mean birth and death rates, then, for any parameter set, the selfing rate does not affect the proportions of resistant, susceptible or infected individuals at equilibrium. If homozygote and heterozygote individual birth rates differ, however, the mating system can make a difference in these proportions. In that case, depending on other parameters, increased selfing can either increase or decrease the rate of infection in the population. Results from this model also predict higher frequencies of resistance alleles in predominantly selfing compared to predominantly outcrossing populations for most model conditions. In populations that have higher selfing rates, the resistance alleles are concentrated in homozygotes, whereas in more outcrossing populations, there are more resistant heterozygotes.
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New support for an old hypothesis: density affects extra-pair paternity
Mayer, Christian; Pasinelli, Gilberto
2013-01-01
Density has been suggested to affect variation in extra-pair paternity (EPP) in avian mating systems, because increasing density promotes encounter rates and thus mating opportunities. However, the significance of density affecting EPP variation in intra- and interspecific comparisons has remained controversial, with more support from intraspecific comparisons. Neither experimental nor empirical studies have consistently provided support for the density hypothesis. Testing the density hypothesis is challenging because density measures may not necessarily reflect extra-pair mating opportunities, mate guarding efforts may covary with density, populations studied may differ in migratory behavior and/or climatic conditions, and variation in density may be insufficient. Accounting for these potentially confounding factors, we tested whether EPP rates within and among subpopulations of the reed bunting (Emberiza schoeniclus) were related to density. Our analyses were based on data from 13 subpopulations studied over 4 years. Overall, 56.4% of totally 181 broods contained at least one extra-pair young (EPY) and 37.1% of totally 669 young were of extra-pair origin. Roughly 90% of the extra-pair fathers were from the adjacent territory or from the territory after the next one. Within subpopulations, the proportion of EPY in broods was positively related to local breeding density. Similarly, among subpopulations, proportion of EPY was positively associated with population density. EPP was absent in subpopulations consisting of single breeding pairs, that is, without extra-pair mating opportunities. Our study confirms that density is an important biological factor, which significantly influences the amount of EPP within and among subpopulations, but also suggests that other mechanisms influence EPP beyond the variation explained by density. PMID:23533071
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Henry, Laurence; Bourguet, Cécile; Coulon, Marion; Aubry, Christine; Hausberger, Martine
2013-02-01
Breeding decisions in birds involve both mate and nest choice, and there is increasing evidence that social influences may modulate individual choices. Female preferences may be affected by other females' preferences and mutual choice cannot always be excluded, which makes the whole pattern more complex than assumed by most sexual selection models. Social transmission may be facilitated by particular social bonds, therefore prebreeding social networks may influence later mate choices. The other case where females share mate or resources is polygyny, generally viewed to only benefit males. If mutual benefits may arise then mechanisms should evolve to reduce the reproductive cost for females such as to reduce the cost of aggression by sharing their mate with a preferred same-sex social partner. We tested the hypothesis that females' mating decisions may be influenced by the prebreeding social network and that social partner relations established prior to breeding may share decisions (mate/sites) in a facultatively polygynous species, the European starling. Two experiments were designed to test the relative importance of male or nest by following the whole dynamics of the breeding cycle from the prebreeding period until mate and nest selection. In both cases socially isolated females tended to be excluded from breeding, while prebreeding social partners tended to share mates and to nest in close proximity, mate copying leading in some case to polygyny. The final pattern resulted both from female "likes and dislikes" and male preferences for some females. Aggressive interactions between females were rare. Vocal sharing between females may have been a clue for males as to the degree of social integration of these females. PsycINFO Database Record (c) 2013 APA, all rights reserved
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Zhang, Dongjing; Lees, Rosemary Susan; Xi, Zhiyong; Bourtzis, Kostas; Gilles, Jeremie R L
2016-01-01
Combination of the sterile insect technique with the incompatible insect technique is considered to be a safe approach to control Aedes albopictus populations in the absence of an accurate and scalable sex separation system or genetic sexing strain. Our previous study has shown that the triple Wolbachia-infected Ae. albopictus strain (wAlbA, wAlbB and wPip) was suitable for mass rearing and females could be completely sterilized as pupae with a radiation dose of at least 28 Gy. However, whether this radiation dose can influence the mating competitiveness of the triple infected males was still unknown. In this study we aimed to evaluate the effects of irradiation on the male mating competitiveness of the triple infected strain under laboratory and semi-field conditions. The results herein indicate that irradiation with a lower, female-sterilizing dose has no negative impact on the longevity of triple infected males while a reduced lifespan was observed in the wild type males (wAlbA and wAlbB) irradiated with a higher male-sterilizing dose, in small cages. At different sterile: fertile release ratios in small cages, triple-infected males induced 39.8, 81.6 and 87.8% sterility in a wild type female population at 1:1, 5:1 and 10:1 release ratios, respectively, relative to a fertile control population. Similarly, irradiated triple infected males induced 31.3, 70.5 and 89.3% sterility at 1:1, 5:1 and 10:1 release ratios, respectively, again relative to the fertile control. Under semi-field conditions at a 5:1 release ratio, relative to wild type males, the mean male mating competitiveness index of 28 Gy irradiated triple-infected males was significantly higher than 35 Gy irradiated wild type males, while triple infected males showed no difference in mean mating competitiveness to either irradiated triple-infected or irradiated wild type males. An unexpected difference was also observed in the relative male mating competitiveness of the triple infected strain after irradiation at 28 Gy dose in small vs large cages, with a higher male mating competitiveness index calculated from results of experiments in the large cages. Based on these results, we consider that the male mating performance of the triple infected strain after irradiation at 28 Gy, a dose required for complete female sterility and the avoidance of population replacement, is approximately equal to that of the wild type males under semi-field conditions. Though field evaluation is required, this suggests that the triple infected strain is suitable for irradiation and release as part of a combined SIT-IIT approach to Ae. albopictus control.
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Zhang, Dongjing; Lees, Rosemary Susan; Xi, Zhiyong; Bourtzis, Kostas; Gilles, Jeremie R. L.
2016-01-01
Combination of the sterile insect technique with the incompatible insect technique is considered to be a safe approach to control Aedes albopictus populations in the absence of an accurate and scalable sex separation system or genetic sexing strain. Our previous study has shown that the triple Wolbachia-infected Ae. albopictus strain (wAlbA, wAlbB and wPip) was suitable for mass rearing and females could be completely sterilized as pupae with a radiation dose of at least 28 Gy. However, whether this radiation dose can influence the mating competitiveness of the triple infected males was still unknown. In this study we aimed to evaluate the effects of irradiation on the male mating competitiveness of the triple infected strain under laboratory and semi-field conditions. The results herein indicate that irradiation with a lower, female-sterilizing dose has no negative impact on the longevity of triple infected males while a reduced lifespan was observed in the wild type males (wAlbA and wAlbB) irradiated with a higher male-sterilizing dose, in small cages. At different sterile: fertile release ratios in small cages, triple-infected males induced 39.8, 81.6 and 87.8% sterility in a wild type female population at 1:1, 5:1 and 10:1 release ratios, respectively, relative to a fertile control population. Similarly, irradiated triple infected males induced 31.3, 70.5 and 89.3% sterility at 1:1, 5:1 and 10:1 release ratios, respectively, again relative to the fertile control. Under semi-field conditions at a 5:1 release ratio, relative to wild type males, the mean male mating competitiveness index of 28 Gy irradiated triple-infected males was significantly higher than 35 Gy irradiated wild type males, while triple infected males showed no difference in mean mating competitiveness to either irradiated triple-infected or irradiated wild type males. An unexpected difference was also observed in the relative male mating competitiveness of the triple infected strain after irradiation at 28 Gy dose in small vs large cages, with a higher male mating competitiveness index calculated from results of experiments in the large cages. Based on these results, we consider that the male mating performance of the triple infected strain after irradiation at 28 Gy, a dose required for complete female sterility and the avoidance of population replacement, is approximately equal to that of the wild type males under semi-field conditions. Though field evaluation is required, this suggests that the triple infected strain is suitable for irradiation and release as part of a combined SIT-IIT approach to Ae. albopictus control. PMID:26990981
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Fertility in South Australian commercial Merino flocks: aspects of management.
Kleemann, David O; Grosser, Timothy I; Walker, Simon K
2006-05-01
Wide variation in reproductive performance of commercial Merino flocks in south central Australia is the result of genetic and environmental influences that are both amenable to change through decisions of management. Relationships of reproductive traits (estrus, ovulation, fertility, fecundity, lamb survival, and lambs weaned) with variables that graziers can change or modify (strain of Merino, day or month of exposure of ewes to rams, ram effect or teasing, length of the mating period, ram percentage, days between weaning and next mating, stocking density and flock size at lambing, ewe liveweight, and condition) are reported in this paper, the third in a series. Small differences were observed between medium and strong-wool South Australian Merino strains for reproductive traits. Choosing the time of year that ewes are exposed to rams, between late spring to autumn, may result in reduced ovulation rate during early summer (December) giving a potentially smaller net reproductive efficiency (lambs weaned). The ram effect or teasing, used by about 50% of graziers to synchronise lambing, could be effectively employed to the end of January. The technique was not reproductively advantageous when compared with flocks that were not teased. The percentage of rams mated to ewes varied widely (approximately 1-3%) and did not alter flock fertility, suggesting that a substantial proportion of graziers could safely reduce the number of rams purchased. A positive relationship between incidence of estrus during the first 14 d of the cycle and the number of days from weaning to next mating and a negative relationship of returns to service with the same variable indicates that managers should consider increasing the time allowed for recovery of liveweight and body condition by adjusting age at weaning, length of the mating period, or both. Lamb survival was curvilinearly related to flock size and not stocking intensity, with the optimum size at about 400 ewes. The number of lambs weaned per 100 ewes exposed to rams increased by 1.0 kg(-1) increase in liveweight at mating. We concluded that the major factor controlling net reproductive efficiency is nutritional in origin through its effects on ewe liveweight and condition, and is a factor that can be largely manipulated through management.
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Mating tactics determine patterns of condition dependence in a dimorphic horned beetle.
Knell, Robert J; Simmons, Leigh W
2010-08-07
The persistence of genetic variability in performance traits such as strength is surprising given the directional selection that such traits experience, which should cause the fixation of the best genetic variants. One possible explanation is 'genic capture' which is usually considered as a candidate mechanism for the maintenance of high genetic variability in sexual signalling traits. This states that if a trait is 'condition dependent', with expression being strongly influenced by the bearer's overall viability, then genetic variability can be maintained via mutation-selection balance. Using a species of dimorphic beetle with males that gain matings either by fighting or by 'sneaking', we tested the prediction of strong condition dependence for strength, walking speed and testes mass. Strength was strongly condition dependent only in those beetles that fight for access to females. Walking speed, with less of an obvious selective advantage, showed no condition dependence, and testes mass was more condition dependent in sneaks, which engage in higher levels of sperm competition. Within a species, therefore, condition dependent expression varies between morphs, and corresponds to the specific selection pressures experienced by that morph. These results support genic capture as a general explanation for the maintenance of genetic variability in traits under directional selection.
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Parrott, Marissa L.; Ward, Simon J.; Temple-Smith, Peter D.; Selwood, Lynne
2015-01-01
Females in a variety of taxa mate with more than one male during a single oestrus and exhibit mate preferences for genetically compatible males, but the influence of female mate choice on siring success is not clearly understood. Whether females choose to mate with more than one male or endure forced copulations is also often unknown. Here, we examined the effects of genetic relatedness on female mate choice and siring success in a small semelparous carnivorous marsupial, the agile antechinus (Antechinus agilis), during two consecutive breeding seasons. Experimental trials were conducted in captivity over periods of 72 hours using interconnected enclosures in which female antechinus could choose to access any of four separated males, but males were only able to access females that entered their quarters. Females had access to two genetically similar and two genetically dissimilar males simultaneously and all behavioural interactions were observed and scored from continuous video recordings. Genetic similarity between mates and paternity of young was determined by microsatellite analyses. Some females chose to enter and mate with more than one male during a single oestrus period. Although females investigated all males, they spent significantly more time visiting, and mated more times with, genetically dissimilar males. Males that were genetically dissimilar to the female sired 88% of subsequent offspring. Whilst males mated readily with most females, they rejected the advances of some receptive females, indicating a previously unexpected level of male mate choice. The results show that genetic relatedness between mates has a significant influence on mate choice, breeding and siring success in the agile antechinus. PMID:25923325
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Parrott, Marissa L; Ward, Simon J; Temple-Smith, Peter D; Selwood, Lynne
2015-01-01
Females in a variety of taxa mate with more than one male during a single oestrus and exhibit mate preferences for genetically compatible males, but the influence of female mate choice on siring success is not clearly understood. Whether females choose to mate with more than one male or endure forced copulations is also often unknown. Here, we examined the effects of genetic relatedness on female mate choice and siring success in a small semelparous carnivorous marsupial, the agile antechinus (Antechinus agilis), during two consecutive breeding seasons. Experimental trials were conducted in captivity over periods of 72 hours using interconnected enclosures in which female antechinus could choose to access any of four separated males, but males were only able to access females that entered their quarters. Females had access to two genetically similar and two genetically dissimilar males simultaneously and all behavioural interactions were observed and scored from continuous video recordings. Genetic similarity between mates and paternity of young was determined by microsatellite analyses. Some females chose to enter and mate with more than one male during a single oestrus period. Although females investigated all males, they spent significantly more time visiting, and mated more times with, genetically dissimilar males. Males that were genetically dissimilar to the female sired 88% of subsequent offspring. Whilst males mated readily with most females, they rejected the advances of some receptive females, indicating a previously unexpected level of male mate choice. The results show that genetic relatedness between mates has a significant influence on mate choice, breeding and siring success in the agile antechinus.
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Intrasexual competition in females: evidence for sexual selection?
Rosvall, Kimberly A
2011-11-01
In spite of recent interest in sexual selection in females, debate exists over whether traits that influence female-female competition are sexually selected. This review uses female-female aggressive behavior as a model behavioral trait for understanding the evolutionary mechanisms promoting intrasexual competition, focusing especially on sexual selection. I employ a broad definition of sexual selection, whereby traits that influence competition for mates are sexually selected, whereas those that directly influence fecundity or offspring survival are naturally selected. Drawing examples from across animal taxa, including humans, I examine 4 predictions about female intrasexual competition based on the abundance of resources, the availability of males, and the direct or indirect benefits those males provide. These patterns reveal a key sex difference in sexual selection: Although females may compete for the number of mates, they appear to compete more so for access to high-quality mates that provide direct and indirect (genetic) benefits. As is the case in males, intrasexual selection in females also includes competition for essential resources required for access to mates. If mate quality affects the magnitude of mating success, then restricting sexual selection to competition for quantity of mates may ignore important components of fitness in females and underestimate the role of sexual selection in shaping female phenotype. In the future, understanding sex differences in sexual selection will require further exploration of the extent of mutual intrasexual competition and the incorporation of quality of mating success into the study of sexual selection in both sexes.
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Intrasexual competition in females: evidence for sexual selection?
2011-01-01
In spite of recent interest in sexual selection in females, debate exists over whether traits that influence female–female competition are sexually selected. This review uses female–female aggressive behavior as a model behavioral trait for understanding the evolutionary mechanisms promoting intrasexual competition, focusing especially on sexual selection. I employ a broad definition of sexual selection, whereby traits that influence competition for mates are sexually selected, whereas those that directly influence fecundity or offspring survival are naturally selected. Drawing examples from across animal taxa, including humans, I examine 4 predictions about female intrasexual competition based on the abundance of resources, the availability of males, and the direct or indirect benefits those males provide. These patterns reveal a key sex difference in sexual selection: Although females may compete for the number of mates, they appear to compete more so for access to high-quality mates that provide direct and indirect (genetic) benefits. As is the case in males, intrasexual selection in females also includes competition for essential resources required for access to mates. If mate quality affects the magnitude of mating success, then restricting sexual selection to competition for quantity of mates may ignore important components of fitness in females and underestimate the role of sexual selection in shaping female phenotype. In the future, understanding sex differences in sexual selection will require further exploration of the extent of mutual intrasexual competition and the incorporation of quality of mating success into the study of sexual selection in both sexes. PMID:22479137
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Wedekind, C; Füri, S
1997-01-01
The major histocompatibility complex (MHC) is an immunologically important group of genes that appears to be under natural as well as sexual selection. Several hypotheses suggest that certain MHC-allele combinations (usually heterozygous ones) are superior under selective pressure by pathogens. This could influence mate choice in a way that preferences function to create MHC-heterozygous offspring, or that they function to create specific allele combinations that are beneficial under the current environmental conditions through their complementary or epistatic effects. To test these hypotheses, we asked 121 men and women to score the odours of six T-shirts, worn by two women and four men. Their scorings of pleasantness correlated negatively with the degree of MHC similarity between smeller and T-shirt-wearer in men and women who were not using the contraceptive pill (but not in Pill-users). Depending on the T-shirt-wearer, the amount of variance in the scorings of odour pleasantness that was explained by the degree of MHC similarity (r2) varied between nearly 0 and 23%. There was no apparent effect of gender in this correlation: the highest r2 was actually reached with one of the male odours sniffed by male smellers. Men and women who were reminded of their own mate/ex-mate when sniffing a T-shirt had significantly fewer MHC-alleles in common with this T-shirt-wearer than expected by chance. This suggests that the MHC or linked genes influence human mate choice. We found no significant effect when we tested for an influence of the MHC on odour preferences after the degree of similarity between T-shirt-wearer and smeller was statistically controlled for. This suggests that in our study populations the MHC influences body odour preferences mainly, if not exclusively, by the degree of similarity or dissimilarity. The observed preferences would increase heterozygosity in the progeny. They do not seem to aim for more specific MHC combinations. PMID:9364787
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Polyandry promotes enhanced offspring survival in decorated crickets.
Ivy, Tracie M; Sakaluk, Scott K
2005-01-01
Although female multiple mating is ubiquitous in insects, its adaptive significance remains poorly understood. Benefits to multiple mating can accrue via direct material benefits, indirect genetic benefits, or both. We investigated the effects of multiple mating in the decorated cricket, Gryllodes sigillatus, by simultaneously varying the number of times that females mated and the number of different males with which they mated, measuring aspects of female fecundity and elements of offspring performance and viability. Multiple matings resulted in enhanced female fitness relative to single matings when females mated with different partners, but not when females mated repeatedly with the same male. Specifically, polyandrous females produced significantly more offspring surviving to reproductive maturity than did monogamous females mating once or mating repeatedly with the same male. These results suggest that the benefit females gain from multiple mating is influenced primarily by genetic and not material benefits.
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Oxytocin receptor density is associated with male mating tactics and social monogamy
Ophir, Alexander G.; Gessel, Ana; Zheng, Da-Jiang; Phelps, Steven M.
2012-01-01
Despite its well-described role in female affiliation, the influence of oxytocin on male pairbonding is largely unknown. However, recent human studies indicate that this nonapeptide has a potent influence on male behaviors commonly associated with monogamy. Here we investigated the distribution of oxytocin receptors (OTR) throughout the forebrain of the socially monogamous male prairie vole (Microtus ochrogaster). Because males vary in both sexual and spatial fidelity, we explored the extent to which OTR predicted monogamous or non-monogamous patterns of space use, mating success and sexual fidelity in free-living males. We found that monogamous males expressed higher OTR density in the nucleus accumbens than non-monogamous males, a result that mirrors species differences in voles with different mating systems. OTR density in the posterior portion of the insula predicted mating success. Finally, OTR in the hippocampus and septohippocampal nucleus, which are nuclei associated with spatial memory, predicted patterns of space use and reproductive success within mating tactics. Our data highlight the importance of oxytocin receptor in neural structures associated with pairbonding and socio-spatial memory in male mating tactics. The role of memory in mating systems is often neglected, despite the fact that mating tactics impose an inherently spatial challenge for animals. Identifying mechanisms responsible for relating information about the social world with mechanisms mediating pairbonding and mating tactics is crucial to fully appreciate the suite of factors driving mating systems. PMID:22285648
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Rapkin, J; Jensen, K; House, C M; Sakaluk, S K; Sakaluk, J K; Hunt, J
2017-04-01
The condition dependence of male sexual traits plays a central role in sexual selection theory. Relatively little, however, is known about the condition dependence of chemical signals used in mate choice and their subsequent effects on male mating success. Furthermore, few studies have isolated the specific nutrients responsible for condition-dependent variation in male sexual traits. Here, we used nutritional geometry to determine the effect of protein (P) and carbohydrate (C) intake on male cuticular hydrocarbon (CHC) expression and mating success in male decorated crickets (Gryllodes sigillatus). We show that both traits are maximized at a moderate-to-high intake of nutrients in a P:C ratio of 1 : 1.5. We also show that female precopulatory mate choice exerts a complex pattern of linear and quadratic sexual selection on this condition-dependent variation in male CHC expression. Structural equation modelling revealed that although the effect of nutrient intake on mating success is mediated through condition-dependent CHC expression, it is not exclusively so, suggesting that other traits must also play an important role. Collectively, our results suggest that the complex interplay between nutrient intake, CHC expression and mating success plays an important role in the operation of sexual selection in G. sigillatus. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.
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Mate-choice copying, social information processing, and the roles of oxytocin.
Kavaliers, Martin; Matta, Richard; Choleris, Elena
2017-01-01
Social and sexual behaviors, including that of mate choice, are dependent on social information. Mate choice can be modified by prior and ongoing social factors and experience. The mate choice decisions of one individual can be influenced by either the actual or potential mate choice of another female or male. Such non-independent mate choice, where individuals gain social information and socially learn about and recognizes potential mates by observing the choices of another female or male, has been termed "mate-choice copying". Here we first briefly review how, why, and under what circumstances individuals engage in mate-choice copying. Secondly, we review the neurobiological mechanisms underlying mate-choice copying. In particular, we consider the roles of the nonapeptide, oxytocin, in the processing of social information and the expression of mate-choice copying. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Little, Anthony C.; Jones, Benedict C.; DeBruine, Lisa M.; Caldwell, Christine A.
2011-01-01
Inspired by studies demonstrating mate-choice copying effects in non-human species, recent studies of attractiveness judgements suggest that social learning also influences human preferences. In the first part of our article, we review evidence for social learning effects on preferences in humans and other animals. In the second part, we present new empirical evidence that social learning not only influences the attractiveness of specific individuals, but can also generalize to judgements of previously unseen individuals possessing similar physical traits. The different conditions represent different populations and, once a preference arises in a population, social learning can lead to the spread of preferences within that population. In the final part of our article, we discuss the theoretical basis for, and possible impact of, biases in social learning whereby individuals may preferentially copy the choices of those with high status or better access to critical information about potential mates. Such biases could mean that the choices of a select few individuals carry the greatest weight, rapidly generating agreement in preferences within a population. Collectively, these issues suggest that social learning mechanisms encourage the spread of preferences for certain traits once they arise within a population and so may explain certain cross-cultural differences. PMID:21199841
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The influence of developmental environment on courtship song in cactophilic Drosophila.
Iglesias, Patricia P; Soto, Eduardo M; Soto, Ignacio M; Colines, Betina; Hasson, Esteban
2018-04-15
Closely related species often differ in the signals involved in sexual communication and mate recognition. Determining the factors influencing signal quality (i.e. signal's content and conspicuousness) provides an important insight into the potential pathways by which these interspecific differences evolve. Host specificity could bias the direction of the evolution of sexual communication and the mate recognition system, favouring sensory channels that work best in the different host conditions. In this study, we focus on the cactophilic sibling species Drosophila buzzatii and D. koepferae that have diverged not only in the sensory channel used for sexual communication and mate recognition but also in the cactus species that use as primary hosts. We evaluate the role of the developmental environment in generating courtship song variation using an isofemale line design. Our results show that host environment during development induces changes in the courtship song of D. koepferae males, but not in D. buzzatii males. Moreover, we report for the first time that host rearing environment affects the conspicuousness of courtship song (i.e. song volume). Our results are mainly discussed in the context of the sensory drive hypothesis. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.
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Esmelindro, Angela Aquino; Girardi, Jonathan Dos Santos; Mossi, Altemir; Jacques, Rosângela Assis; Dariva, Cláudio
2004-04-07
The aim of this work is to assess the influence of light intensity (plants with direct sun exposure and in a controlled light intensity) and age of leaves (6-24 months) on the characteristics of the extracts of mate tea leaves obtained from carbon dioxide at high pressures. Samples of mate were collected in an experiment conducted under agronomic control at Industria e Comercio de Erva-Mate Barão LTDA, Brazil. The content of selected organic compounds of the extracts was evaluated by gas chromatography together with mass spectrometry. Quantitative analysis of caffeine, theobromine, phytol, vitamin E, squalene, and stigmasterol was performed, and the results showed that field variables exert a strong influence on the liquid yield and on the chemical distribution of the extracts.
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OCT2 and MATE1 Provide Bi-directional Agmatine Transport
Winter, Tate N.; Elmquist, William F.; Fairbanks, Carolyn A.
2015-01-01
Agmatine is a biogenic amine (l-arginine metabolite) of potential relevance to several central nervous system (CNS) conditions. The identities of transporters underlying agmatine and polyamine disposition in mammalian systems are not well defined. The SLC-family organic cation transporters (OCT) OCT1 and OCT2 and multidrug and toxin extrusion transporter-1 (MATE1) are transport systems that may be of importance for the cellular disposition of agmatine and putrescine. We investigated the transport of [3H]-agmatine and [3H]-putrescine in human embryonic kidney (HEK293) cells stably-transfected with hOCT1-, hOCT2-, and hMATE1. Agmatine transport by hOCT1 and hOCT2 was concentration-dependent, whereas only hOCT2 demonstrated pH-dependent transport. hOCT2 exhibited a greater affinity for agmatine (Km = 1.84 ± 0.38 mM) than did hOCT1 (Km = 18.73 ± 4.86 mM). Putrescine accumulation was pH- and concentration-dependent in hOCT2-HEK cells (Km = 11.29 ± 4.26 mM) but not hOCT1-HEK cells. Agmatine accumulation, in contrast to putrescine, was significantly enhanced by hMATE1 over-expression, and was saturable (Km = 240 ± 31 μM; Vmax = 192 ± 10 pmol/min/mg protein). Intracellular agmatine was also trans-stimulated (effluxed) from hMATE1-HEK cells in the presence of an inward proton-gradient. The hMATE1-mediated transport of agmatine was inhibited by polyamines, the prototypical substrates MPP+ and paraquat, as well as guanidine and arcaine, but not l-arginine. These results suggest that agmatine disposition may be influenced by hOCT2 and hMATE1, two transporters critical in the renal elimination of xenobiotic compounds. PMID:21128598
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Havens, J A; Etges, W J
2013-03-01
Sexual signals in cactophilic Drosophila mojavensis include cuticular hydrocarbons (CHCs), contact pheromones that mediate female discrimination of males during courtship. CHCs, along with male courtship songs, cause premating isolation between diverged populations, and are influenced by genotype × environment interactions caused by different host cacti. CHC profiles of mated and unmated adult flies from a Baja California and a mainland Mexico population of D. mojavensis reared on two host cacti were assayed to test the hypothesis that male CHCs mediate within-population female discrimination of males. In multiple choice courtship trials, mated and unmated males differed in CHC profiles, indicating that females prefer males with particular blends of CHCs. Mated and unmated females significantly differed in CHC profiles as well. Adults in the choice trials had CHC profiles that were significantly different from those in pair-mated adults from no-choice trials revealing an influence of sexual selection. Females preferred different male CHC blends in each population, but the influence of host cactus on CHC variation was significant only in the mainland population indicating population-specific plasticity in CHCs. Different groups of CHCs mediated female choice-based sexual selection in each population suggesting that geographical and ecological divergence has the potential to promote divergence in mate communication systems. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.
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Järvenpää, Marja; Lindström, Kai
2004-11-22
Eutrophication as a result of human activity has resulted in increased algal blooms and turbidity in aquatic environments. We investigated experimentally the effect of algal turbidity on the mating system and sexual selection in the sand goby, Pomatoschistus minutus (Pallas), a marine fish with a resource-defence mating system and paternal care. Owing to male-male competition and female choice, large males can monopolize multiple mates, while some males do not achieve mating at all. We show that the number of eggs laid was the same in both turbid and clear tanks but that mating success was more evenly distributed among males in turbid than in clear water. The opportunity for sexual selection was lower in turbid conditions. In turbid conditions mating success was less skewed towards large males. Our results suggest that increased turbidity can change mating systems and decrease the opportunity for sexual selection as well as selection intensity.
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Oxytocin receptor density is associated with male mating tactics and social monogamy.
Ophir, Alexander G; Gessel, Ana; Zheng, Da-Jiang; Phelps, Steven M
2012-03-01
Despite its well-described role in female affiliation, the influence of oxytocin on male pairbonding is largely unknown. However, recent human studies indicate that this nonapeptide has a potent influence on male behaviors commonly associated with monogamy. Here we investigated the distribution of oxytocin receptors (OTR) throughout the forebrain of the socially monogamous male prairie vole (Microtus ochrogaster). Because males vary in both sexual and spatial fidelity, we explored the extent to which OTR predicted monogamous or non-monogamous patterns of space use, mating success and sexual fidelity in free-living males. We found that monogamous males expressed higher OTR density in the nucleus accumbens than non-monogamous males, a result that mirrors species differences in voles with different mating systems. OTR density in the posterior portion of the insula predicted mating success. Finally, OTR in the hippocampus and septohippocampal nucleus, which are nuclei associated with spatial memory, predicted patterns of space use and reproductive success within mating tactics. Our data highlight the importance of oxytocin receptor in neural structures associated with pairbonding and socio-spatial memory in male mating tactics. The role of memory in mating systems is often neglected, despite the fact that mating tactics impose an inherently spatial challenge for animals. Identifying mechanisms responsible for relating information about the social world with mechanisms mediating pairbonding and mating tactics is crucial to fully appreciate the suite of factors driving mating systems. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior. Published by Elsevier Inc.
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Toft, S; Albo, M J
2015-02-01
In species where females gain a nutritious nuptial gift during mating, the balance between benefits and costs of mating may depend on access to food. This means that there is not one optimal number of matings for the female but a range of optimal mating numbers. With increasing food availability, the optimal number of matings for a female should vary from the number necessary only for fertilization of her eggs to the number needed also for producing these eggs. In three experimental series, the average number of matings for females of the nuptial gift-giving spider Pisaura mirabilis before egg sac construction varied from 2 to 16 with food-limited females generally accepting more matings than well-fed females. Minimal level of optimal mating number for females at satiation feeding conditions was predicted to be 2-3; in an experimental test, the median number was 2 (range 0-4). Multiple mating gave benefits in terms of increased fecundity and increased egg hatching success up to the third mating, and it had costs in terms of reduced fecundity, reduced egg hatching success after the third mating, and lower offspring size. The level of polyandry seems to vary with the female optimum, regulated by a satiation-dependent resistance to mating, potentially leaving satiated females in lifelong virginity. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.
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Boosting beauty in an economic decline: mating, spending, and the lipstick effect.
Hill, Sarah E; Rodeheffer, Christopher D; Griskevicius, Vladas; Durante, Kristina; White, Andrew Edward
2012-08-01
Although consumer spending typically declines in economic recessions, some observers have noted that recessions appear to increase women's spending on beauty products--the so-called lipstick effect. Using both historical spending data and rigorous experiments, the authors examine how and why economic recessions influence women's consumer behavior. Findings revealed that recessionary cues--whether naturally occurring or experimentally primed--decreased desire for most products (e.g., electronics, household items). However, these cues consistently increased women's desire for products that increase attractiveness to mates--the first experimental demonstration of the lipstick effect. Additional studies show that this effect is driven by women's desire to attract mates with resources and depends on the perceived mate attraction function served by these products. In addition to showing how and why economic recessions influence women's desire for beauty products, this research provides novel insights into women's mating psychology, consumer behavior, and the relationship between the two.
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Partitioning the effects of mating and nuptial feeding on the microbiome in gift-giving insects
USDA-ARS?s Scientific Manuscript database
Mating is a ubiquitous social interaction that has the potential to influence the microbiome by facilitating transmission, modifying host physiology, and in species where males donate nuptial gifts to females, altering diet. We manipulated mating and nuptial gift consumption in two insects that diff...
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Effects of partner beauty on opposite-sex attractiveness judgments.
Little, Anthony C; Caldwell, Christine A; Jones, Benedict C; DeBruine, Lisa M
2011-12-01
Many studies show mate choice copying effects on mate preferences in non-human species in which individuals follow or copy the mate choices of same-sex conspecifics. Recent studies suggest that social learning also influences mate preferences in humans. Studies on heterosexual humans have focused on rating the attractiveness of potential mates (targets) presented alongside individuals of the opposite sex to the target (models). Here, we examined several different types of pairing to examine how specific social learning is to mate preferences. In Study 1, we replicated a previous effect whereby target faces of the opposite sex to the subject were rated as more attractive when paired with attractive than unattractive partner models of the same sex as the subject. Using the same paired stimuli, Study 2 demonstrated no effect of a paired model if subjects were asked to rate targets who were the same sex as themselves. In Study 3, we used pairs of the same sex, stating the pair were friends, and subjects rated targets of the opposite sex to themselves. Attractive models decreased targets' attractiveness, opposite to the effect in Study 1. Finally, Study 4 examined if attractive versus unattractive non-face stimuli might influence attraction. Unlike in Study 1, pairing with attractive stimuli either had no effect or decreased the attractiveness of paired target face images. These data suggest that social transmission of preferences via pairing with attractive/unattractive images is relatively specific to learning about mate preferences but does not influence attractiveness judgments more generally.
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2018-01-01
Abstract Research on sexual selection and hybridization has focused on female mate choice and male–male competition. While the evolutionary outcomes of interspecific female preference have been well explored, we are now gaining a better understanding of the processes by which male–male competition between species in secondary contact promotes reproductive isolation versus hybridization. What is relatively unexplored is the interaction between female choice and male competition, as they can oppose one another or align with similar outcomes for reproductive isolation. The role of female–female competition in hybridization is also not well understood, but could operate similarly to male–male competition in polyandrous and other systems where costs to heterospecific mating are low for females. Reproductive competition between either sex of sympatric species can cause the divergence and/or convergence of sexual signals and recognition, which in turn influences the likelihood for interspecific mating. Future work on species interactions in secondary contact should test the relative influences of both mate choice and competition for mates on hybridization outcomes, and should not ignore the possibilities that females can compete over mating resources, and males can exercise mate choice. PMID:29492041
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Genetic incompatibility drives mate choice in a parasitic wasp.
Thiel, Andra; Weeda, Anne C; de Boer, Jetske G; Hoffmeister, Thomas S
2013-07-30
Allelic incompatibility between individuals of the same species should select for mate choice based on the genetic make-up of both partners at loci that influence offspring fitness. As a consequence, mate choice may be an important driver of allelic diversity. A complementary sex determination (CSD) system is responsible for intraspecific allelic incompatibility in many species of ants, bees, and wasps. CSD may thus favour disassortative mating and in this, resembles the MHC of the vertebrate immune system, or the self-incompatibility (SI) system of higher plants. Here we show that in the monogamous parasitic wasp Bracon brevicornis (Wesmael), females are able to reject partners with incompatible alleles. Forcing females to accept initially rejected partners resulted in sex ratio distortion and partial infertility of offspring. CSD-disassortative mating occurred independent of kin recognition and inbreeding avoidance in our experiment. The fitness consequences of mate choice are directly observable, not influenced by environmental effects, and more severe than in comparable systems (SI or MHC), on individuals as well as at the population level. Our results thus demonstrate the strong potential of female mate choice for maintaining high offspring fitness in this species.
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A Role of DLPFC in the Learning Process of Human Mate Copying
Zhuang, Jin-Ying; Xie, Jiajia; Hu, Die; Fan, Mingxia; Zheng, Li
2016-01-01
In the current study, we conducted a behavioral experiment to test the mate coping effect and a functional magnetic resonance imaging (fMRI) experiment to test the neural basis involved in the social learning process of mate copying. In the behavioral experiment, participants were asked to rate the attractiveness of isolated opposite-sex (potential mates) facial photographs, then shown the targets associating with a neutral-faced model with textual cues indicating the models’ attitude (interested vs. not-interested) toward the potential mates, and then asked to re-evaluate the potential mates’ attractiveness. Using a similar procedure as the behavioral experiment, participants were scanned while observing the compound images in the fMRI experiment. The mate copying effect was confirmed in the behavioral experiment –greater increase in attractiveness ratings was observed for opposite-sex photographs in the interested than in the not-interested condition. The fMRI results showed that the dorsolateral prefrontal gyrus (DLPFC) was significantly active in the comparison of interested > not-interested condition, suggesting that a cognitive integration and selection function may be involved when participants process information from conditions related to mate copying. PMID:27148151
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Tóth, Zoltán; Griggio, Matteo
2011-01-01
Social network theory provides a perfect tool to better understand the population-level consequences of how individuals interact and make their decisions; however, this approach is generally overlooked among evolutionary biologists interested in social relationships. Here, we used social network analysis to examine the patterns of leader-follower interactions in relation to individual characteristics in foraging groups of free-living rock sparrows (Petronia petronia). We found that yellow feather ornamentation, a carotenoid-based trait, was the best predictor of leadership: birds with bigger ornaments exerted greater influence in the foraging groups and were followed by more group-mates than less elaborate individuals. An individual's tendency for eliciting followings was not influenced by sex, condition or the level of parental investment. None of the above individual characteristics had significant effect on the tendency of individuals to follow others. Our results indicate that a sexually selected trait can also play a significant role in group coordination and social organization of a species.
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Phillips, Tim; Ferguson, Eamonn; Rijsdijk, Fruhling
2010-11-01
Altruistic behaviour raises major questions for psychology and biology. One hypothesis proposes that human altruistic behaviour evolved as a result of sexual selection. Mechanisms that seek to explain how sexual selection works suggest genetic influence acting on both the mate preference for the trait and the preferred trait itself. We used a twin study to estimate whether genetic effects influenced responses to psychometric scales measuring mate preference towards altruistic traits (MPAT) and the preferred trait (i.e., 'altruistic personality'). As predicted, we found significant genetic effects influencing variation in both. We also predicted that individuals expressing stronger MPAT and 'altruistic personality' would have mated at a greater frequency in ancestral populations. We found evidence for this in that 67% of the covariance in the phenotypic correlation between the two scales was associated with significant genetic effects. Both sets of findings are thus consistent with the hypothesized link between sexual selection and human altruism towards non-kin. We discuss how this study contributes to our understanding of altruistic behaviour and how further work might extend this understanding.
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NASA Astrophysics Data System (ADS)
Badás, E. P.; Martínez, J.; Rivero-de Aguilar, J.; Ponce, C.; Stevens, M.; Merino, S.
2018-02-01
Carry-over effects refer to processes that occur in one season and influence fitness in the following. In birds, two costly activities, namely reproduction and moult, are restricted to a small time window, and sometimes overlap. Thus, colour in newly moulted feathers is likely to be affected by the costs of reproduction. Using models of bird vision we investigated male colour change in a free-living population of blue tits ( Cyanistes caeruleus) in three sampling occasions: spring 1, winter and spring 2. We related crown, tail, breast and cheek feather colouration after the moult (winter) to the intensity of infections by blood parasites during reproduction (spring 1). In the following spring (spring 2), we explored mating patterns with respect to changes in feather colour (springs 1 vs. 2). Males that were less intensely infected by the malaria parasite Plasmodium while breeding showed purer white cheek feathers in winter, which may indicate higher feather quality. Increased brightness in the white cheek was associated with better body condition during reproduction. In the following season, males with brighter cheeks paired with females that had noticeably brighter cheek patches compared to the male's previous mate. These results suggest that the conditions experienced during reproduction are likely to affect moult and thus feather colouration, at least in the white patch. High quality individuals may allocate resources efficiently during reproduction increasing future reproductive success through variation in mating patterns. Carry-over effects from reproduction might extend not only to the non-breeding phase, but also to the following breeding season.
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Badás, E P; Martínez, J; Rivero-de Aguilar, J; Ponce, C; Stevens, M; Merino, S
2018-02-06
Carry-over effects refer to processes that occur in one season and influence fitness in the following. In birds, two costly activities, namely reproduction and moult, are restricted to a small time window, and sometimes overlap. Thus, colour in newly moulted feathers is likely to be affected by the costs of reproduction. Using models of bird vision we investigated male colour change in a free-living population of blue tits (Cyanistes caeruleus) in three sampling occasions: spring 1, winter and spring 2. We related crown, tail, breast and cheek feather colouration after the moult (winter) to the intensity of infections by blood parasites during reproduction (spring 1). In the following spring (spring 2), we explored mating patterns with respect to changes in feather colour (springs 1 vs. 2). Males that were less intensely infected by the malaria parasite Plasmodium while breeding showed purer white cheek feathers in winter, which may indicate higher feather quality. Increased brightness in the white cheek was associated with better body condition during reproduction. In the following season, males with brighter cheeks paired with females that had noticeably brighter cheek patches compared to the male's previous mate. These results suggest that the conditions experienced during reproduction are likely to affect moult and thus feather colouration, at least in the white patch. High quality individuals may allocate resources efficiently during reproduction increasing future reproductive success through variation in mating patterns. Carry-over effects from reproduction might extend not only to the non-breeding phase, but also to the following breeding season.
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Mate guarding in the Seychelles warbler is energetically costly and adjusted to paternity risk.
Komdeur, J
2001-10-22
Males may increase their fitness through extra-pair copulations (copulations outside the pair bond) that result in extra-pair fertilizations, but also risk lost paternity when they leave their own mate unguarded. The fitness costs of cuckoldry for Seychelles warblers (Acrocephalus sechellensis) are considerable because warblers have a single-egg clutch and, given the short breeding season, no time for a successful replacement clutch. Neighbouring males are the primary threat to a male's genetic paternity. Males minimize their loss of paternity by guarding their mates to prevent them from having extra-pair copulations during their fertile period. Here, I provide experimental evidence that mate-guarding behaviour is energetically costly and that the expression of this trade-off is adjusted to paternity risk (local male density). Free-living males that were induced to reduce mate guarding spent significantly more time foraging and gained significantly better body condition than control males. The larger the reduction in mate guarding, the more pronounced was the increase in foraging and body condition (accounting for food availability). An experimental increase in paternity risk resulted in an increase in mate-guarding intensity and a decrease in foraging and body condition, and vice versa. This is examined using both cross-sectional and longitudinal data. This study on the Seychelles warbler offers experimental evidence that mate guarding is energetically costly and adjusted to paternity risk.
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Mate choice for genetic compatibility in the house mouse
Lindholm, Anna K; Musolf, Kerstin; Weidt, Andrea; König, Barbara
2013-01-01
In house mice, genetic compatibility is influenced by the t haplotype, a driving selfish genetic element with a recessive lethal allele, imposing fundamental costs on mate choice decisions. Here, we evaluate the cost of genetic incompatibility and its implication for mate choice in a wild house mice population. In laboratory reared mice, we detected no fertility (number of embryos) or fecundity (ability to conceive) costs of the t, and yet we found a high cost of genetic incompatibility: heterozygote crosses produced 40% smaller birth litter sizes because of prenatal mortality. Surprisingly, transmission of t in crosses using +/t males was influenced by female genotype, consistent with postcopulatory female choice for + sperm in +/t females. Analysis of paternity patterns in a wild population of house mice showed that +/t females were more likely than +/+ females to have offspring sired by +/+ males, and unlike +/+ females, paternity of their offspring was not influenced by +/t male frequency, further supporting mate choice for genetic compatibility. As the major histocompatibility complex (MHC) is physically linked to the t, we investigated whether females could potentially use variation at the MHC to identify male genotype at the sperm or individual level. A unique MHC haplotype is linked to the t haplotype. This MHC haplotype could allow the recognition of t and enable pre- and postcopulatory mate choice for genetic compatibility. Alternatively, the MHC itself could be the target of mate choice for genetic compatibility. We predict that mate choice for genetic compatibility will be difficult to find in many systems, as only weak fertilization biases were found despite an exceptionally high cost of genetic incompatibility. PMID:23762510
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Apostólico, Lígia H; Marian, José E A R
2017-11-01
Sperm competition is a powerful postcopulatory selective force influencing male adaptations associated with increasing fertilization success, and it is usually related to the evolution of different strategies of ejaculate expenditure between individuals. Ejaculates may also be influenced by additional selective pressures associated with sperm competition, such as timing between insemination and fertilization, female reproductive tract morphology, and fertilization environment. Also, males that adopt alternative mating tactics may face distinct sperm competition pressures, which may lead to the evolution of intraspecific diversity in ejaculates. In loliginid squids, males with alternative reproductive tactics (sneakers and consorts) differ not only in mating behavior, but also transfer spermatophores into two distinct sites within the female. Here, we compared structure and functioning of spermatophores between sneakers and consorts in the squid Doryteuthis plei applying microscopy techniques and in vitro experiments. Sneakers and consorts exhibit differences in spermatophore structure that lead to distinct spermatophoric reactions and spermatangium morphologies. Moreover, in sneakers, sperm release lasts longer and their sperm show an aggregative behavior not detected in consorts. Slow sperm release may be a strategy to guarantee longer sperm provision, given the wide interval between sneaker mating and egg release. For consorts, in turn, intense and quick sperm discharge may be advantageous, as timing between mating and egg-laying is relatively short. Within the complex squid mating system, factors such as (i) different fertilization sites and (ii) interval between mating and egg release may also influence sperm competition, and ultimately shape the evolution of divergent ejaculates between dimorphic males. © 2017 Wiley Periodicals, Inc.
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Can sexual selection theory inform genetic management of captive populations? A review
Chargé, Rémi; Teplitsky, Céline; Sorci, Gabriele; Low, Matthew
2014-01-01
Captive breeding for conservation purposes presents a serious practical challenge because several conflicting genetic processes (i.e., inbreeding depression, random genetic drift and genetic adaptation to captivity) need to be managed in concert to maximize captive population persistence and reintroduction success probability. Because current genetic management is often only partly successful in achieving these goals, it has been suggested that management insights may be found in sexual selection theory (in particular, female mate choice). We review the theoretical and empirical literature and consider how female mate choice might influence captive breeding in the context of current genetic guidelines for different sexual selection theories (i.e., direct benefits, good genes, compatible genes, sexy sons). We show that while mate choice shows promise as a tool in captive breeding under certain conditions, for most species, there is currently too little theoretical and empirical evidence to provide any clear guidelines that would guarantee positive fitness outcomes and avoid conflicts with other genetic goals. The application of female mate choice to captive breeding is in its infancy and requires a goal-oriented framework based on the needs of captive species management, so researchers can make honest assessments of the costs and benefits of such an approach, using simulations, model species and captive animal data. PMID:25553072
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The scent of inbreeding: a male sex pheromone betrays inbred males
van Bergen, Erik; Brakefield, Paul M.; Heuskin, Stéphanie; Zwaan, Bas J.; Nieberding, Caroline M.
2013-01-01
Inbreeding depression results from mating among genetically related individuals and impairs reproductive success. The decrease in male mating success is usually attributed to an impact on multiple fitness-related traits that reduce the general condition of inbred males. Here, we find that the production of the male sex pheromone is reduced significantly by inbreeding in the butterfly Bicyclus anynana. Other traits indicative of the general condition, including flight performance, are also negatively affected in male butterflies by inbreeding. Yet, we unambiguously show that only the production of male pheromones affects mating success. Thus, this pheromone signal informs females about the inbreeding status of their mating partners. We also identify the specific chemical component (hexadecanal) probably responsible for the decrease in male mating success. Our results advocate giving increased attention to olfactory communication as a major causal factor of mate-choice decisions and sexual selection. PMID:23466986
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Li, Xiao-Wei; Jiang, Hong-Xue; Zhang, Xiao-Chen; Shelton, Anthony M; Feng, Ji-Nian
2014-01-01
Post-mating, sexual interactions of opposite sexes differ considerably in different organisms. Post-mating interactions such as re-mating behavior and male harassment can affect the fitness of both sexes. Echinothrips americanus is a new insect pest in Mainland China, and little is known about its post-mating interactions. In this study, we observed re-mating frequency and male harassment frequency and their effects on fitness parameters and offspring sex ratios of E. americanus females. Furthermore, we tested the impact of mating and post-mating interactions on fitness parameters of males. Our results revealed that the re-mating frequency in female adults was extremely low during a 30-day period. However, post-mating interactions between females and males, consisting mainly of male harassment and female resistance, did occur and significantly reduced female longevity and fecundity. Interestingly, increased access to males did not affect the ratio of female offspring. For males, mating dramatically reduced their longevity. However, post-mating interactions with females had no effects on the longevity of mated males. These results enrich our basic knowledge about female and male mating and post-mating behaviors in this species and provide important information about factors that may influence population regulation of this important pest species.
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Mating behaviour of Pseudodiaptomus annandalei (Copepoda, Calanoida) in calm and turbulent waters
NASA Astrophysics Data System (ADS)
Lee, C. H.; Dahms, H. U.; Cheng, S. H.; Souissi, S.; Schmitt, F. G.; Kumar, R.; Hwang, J. S.
2009-04-01
Behavioral observations of male copepods reveal that they commonly follow female copepods' footprints to find their mates. Female generated environmental signals are primarily of hydromechanical or chemical quality. The intensity of hydromechanical or chemical signals is affected by the hydrodynamic conditions which in turn may modulate a copepod's ability to sense signals in their search for mates in the aquatic environment. We studied the patterns and efficiency of the copepod Pseudodiaptomus annandalei to mate at still and turbulent water conditions during day and night and in different shape and volume experimental containers. The ability of courtship in P. annandalei was recorded to be a negative function of hydromechanical disturbances as the successful mating was observed in still water only. Under turbulent condition males were not able to track a female properly. We records in the present study that both, sequential and simultaneous taxi mechanisms are used by the male P. annandalei to follow either hydromechanic or chemical signals. Our results further reveal that males follow a signal more accurately characterized as a trail. The ability of P. annandalei males to track a three-dimensional trail appears unique, and possibly depends on the persistence of fluid-borne hydromechanical or chemical signals created in low Reynolds number hydrodynamic regimes. Keywords: Mating behavior, Turbulence, Flow, Hydrodynamic conditions
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Mate choice for genetic quality when environments vary: suggestions for empirical progress.
Bussière, Luc F; Hunt, John; Stölting, Kai N; Jennions, Michael D; Brooks, Robert
2008-09-01
Mate choice for good-genes remains one of the most controversial evolutionary processes ever proposed. This is partly because strong directional choice should theoretically deplete the genetic variation that explains the evolution of this type of female mating preference (the so-called lek paradox). Moreover, good-genes benefits are generally assumed to be too small to outweigh opposing direct selection on females. Here, we review recent progress in the study of mate choice for genetic quality, focussing particularly on the potential for genotype by environment interactions (GEIs) to rescue additive genetic variation for quality, and thereby resolve the lek paradox. We raise five questions that we think will stimulate empirical progress in this field, and suggest directions for research in each area: (1) How is condition-dependence affected by environmental variation? (2) How important are GEIs for maintaining additive genetic variance in condition? (3) How much do GEIs reduce the signalling value of male condition? (4) How does GEI affect the multivariate version of the lek paradox? (5) Have mating biases for high-condition males evolved because of indirect benefits?
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Environmental change disrupts communication and sexual selection in a stickleback population.
Candolin, Ulrika; Tukiainen, Iina; Bertell, Elina
2016-04-01
Environmental change that disrupts communication during mate choice and alters sexual selection could influence population dynamics. Yet little is known about such long-term effects. We investigated experimentally the consequences that disrupted visual communication during mate choice has for the quantity and viability of offspring produced in a threespine stickleback population (Gasterosteus aculeatus). We further related the results to long-term monitoring of population dynamics in the field to determine if changes are apparent under natural conditions. The results show that impaired visual communication because of algal blooms reduces reliability of male visual signals as indicators of offspring survival during their first weeks of life. This relaxes sexual selection but has no effect on the number of offspring hatching, as most males have a high hatching success in turbid water. Despite eutrophication and high turbidity levels that interfere with communication during mate choice, the population has grown during recent decades. Large numbers of offspring hatching, combined with high variation in juvenile fitness, has probably shifted selection to later life history stages and maintained a viable population. Together with reduced cost of sexual selection and ongoing ecosystem changes caused by human activities, this could have promoted population growth. These results point to the complexity of ecosystems and the necessity to consider all influencing factors when attempting to understand impacts of human activities on populations.
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Watts, David P
2015-04-01
Male mating tactics vary extensively in many primates. Some variation occurs because adolescent males often are sexually active but cannot invest heavily in mating effort because of their limited ability to compete directly with adults and because they are still investing in growth; consequently, most of their mating attempts may be surreptitious and/or with females whose fecundity is low. Chimpanzees (Pan troglodytes) have a complex mating system: most copulations occur between estrous females with full sexual swelling and multiple males in group settings where the potential for sperm competition is high, but males sometimes mate-guard females, and sometimes male-female pairs mate exclusively with each other while avoiding other males during "consortships." Among other factors, dominance ranks, coalition formation, and variation in male-female association influence male mating and reproductive success. Mating effort increases from adolescence into prime adulthood. At Gombe and Mahale, adolescent males copulated more with nulliparous than with parous females, and mostly when females were unlikely to be ovulating, partly because of low adult male interest in nulliparous females and partly because of aggression from or avoidance of adult males. Adolescents thus had low probabilities of siring infants. However, adolescents are known to have gained some paternity at Gombe and in other populations, and their mating behavior deserves more study. I present data on mating by adolescent males in an unusually large chimpanzee community at Ngogo, Kibale National Park, Uganda. Adolescents at Ngogo also copulated more with nulliparous than parous females and mostly copulated outside of periovulatory periods. Also, they directed less aggression at estrous females than did adult males. However, they gained lower shares of copulations than reported for Gombe and Mahale, regardless of female parity, and received more aggression from adult males. These differences might partly reflect the influence of variation in the number of males per community on male mating tactics.
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Kopps, Anna M; Kang, Jungkoo; Sherwin, William B; Palsbøll, Per J
2015-06-30
Kinship analyses are important pillars of ecological and conservation genetic studies with potentially far-reaching implications. There is a need for power analyses that address a range of possible relationships. Nevertheless, such analyses are rarely applied, and studies that use genetic-data-based-kinship inference often ignore the influence of intrinsic population characteristics. We investigated 11 questions regarding the correct classification rate of dyads to relatedness categories (relatedness category assignments; RCA) using an individual-based model with realistic life history parameters. We investigated the effects of the number of genetic markers; marker type (microsatellite, single nucleotide polymorphism SNP, or both); minor allele frequency; typing error; mating system; and the number of overlapping generations under different demographic conditions. We found that (i) an increasing number of genetic markers increased the correct classification rate of the RCA so that up to >80% first cousins can be correctly assigned; (ii) the minimum number of genetic markers required for assignments with 80 and 95% correct classifications differed between relatedness categories, mating systems, and the number of overlapping generations; (iii) the correct classification rate was improved by adding additional relatedness categories and age and mitochondrial DNA data; and (iv) a combination of microsatellite and single-nucleotide polymorphism data increased the correct classification rate if <800 SNP loci were available. This study shows how intrinsic population characteristics, such as mating system and the number of overlapping generations, life history traits, and genetic marker characteristics, can influence the correct classification rate of an RCA study. Therefore, species-specific power analyses are essential for empirical studies. Copyright © 2015 Kopps et al.
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Lanctot, Richard B.; Weatherhead, Patrick J.; Kempenaers, Bart; Scribner, Kim T.
1998-01-01
Buff-breasted sandpipers use a variety of mating tactics to acquire mates, including remaining at a single lek for most of the breeding season, attending multiple leks during the season, displaying solitarily or displaying both on leks and solitarily. We found that differences in body size, body condition, fluctuating asymmetry scores, wing coloration, territory location and behaviour (attraction, solicitation and agonistic) did not explain the observed variation in mating tactics used by males. Which males abandoned versus returned to leks was also not related to morphology or behaviour, and there was no tendency for males to join leks that were larger or smaller than the lek they abandoned. These results suggest that male desertion of leks was not dependent on a male's characteristics nor on the size of the lek he was presently attending. Males did join leks with larger males than their previous lek, perhaps to mate with females attracted to these larger 'hotshot' males. Males at both leks and solitary sites successfully mated. Lek tenure did not affect mating success, although lekking males appeared to mate more frequently than solitary males. Courtship disruption and to a lesser extent, female mimicry, were effective at preventing females from mating at leks, and may offer a partial explanation for female mating off leks. Our analysis that combined all males together within a year (regardless of mating tactic) indicated that males that attended leks for longer periods of time and that had fewer wing spots were significantly more likely to mate. Given some evidence that wing spotting declines with age, and that females inspect male underwings during courtship, the latter result suggests that female choice may play some role in determining male success. We suggest that male buff-breasted sandpipers may use alternative mating tactics more readily than males in other 'classic' lek-breeding species because: (1) unpredictable breeding conditions in this species' high arctic breeding range leads to low lek stability, which in turn hinders mate selection mechanisms mediated by male dominance and female choice; and (2) males are not constrained by morphological markings that indicate status or sex. Both characteristics may reduce the reproductive benefits associated with males adopting one mating tactic and result in a sort of scramble competition in which males switch between tactics as local conditions change.
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An integrative view of sexual selection in Tribolium flour beetles.
Fedina, Tatyana Y; Lewis, Sara M
2008-05-01
Sexual selection is a major force driving the evolution of diverse reproductive traits. This evolutionary process is based on individual reproductive advantages that arise either through intrasexual competition or through intersexual choice and conflict. While classical studies of sexual selection focused mainly on differences in male mating success, more recent work has focused on the differences in paternity share that may arise through sperm competition or cryptic female choice whenever females mate with multiple males. Thus, an integrative view of sexual selection needs to encompass processes that occur not only before copulation (pre-mating), but also during copulation (peri-mating), as well as after copulation (post-mating), all of which can generate differences in reproductive success. By encompassing mechanisms of sexual selection across all of these sequential reproductive stages this review takes an integrative approach to sexual selection in Tribolium flour beetles (Coleoptera: Tenebrionidae), a particularly well-studied and economically important model organism. Tribolium flour beetles colonize patchily distributed grain stores, and juvenile and adult stages share the same food resources. Adults are highly promiscuous and female reproduction is distributed across an adult lifespan lasting approximately 1 year. While Tribolium males produce an aggregation pheromone that attracts both sexes, there appears to be little pre-mating discrimination among potential mates by either sex. However, recent work has revealed several peri-mating and post-mating mechanisms that determine how offspring paternity is apportioned among a female's mates. During mating, Tribolium females reject spermatophore transfer and limit sperm numbers transferred by males with low phenotypic quality. Although there is some conflicting evidence, male copulatory leg-rubbing appears to be associated with overcoming female resistance to insemination and does not influence a male's subsequent paternity share. Evidence suggests that Tribolium beetles have several possible post-mating mechanisms that they may use to bias paternity. Male sperm precedence has been extensively studied in Tribolium spp. and the related Tenebrio molitor, and several factors influencing male paternity share among a female's progeny have been identified. These include oviposition time, inter-mating interval, male strain/genotype, the mating regimen of a male's mother, male starvation, and tapeworm infection. Females exert muscular control over sperm storage, although there is no evidence to date that females use this to differentiate among mates. Females could also influence offspring paternity by re-mating with additional males, and T. castaneum females more readily accept spermatophores when they are re-mating with more attractive males. Additional work is needed to examine the possible roles played by both male and female accessory gland products in determining male paternity share. Sexual selection during pre-mating episodes may be reinforced or counteracted by peri- and post-copulatory selection, and antagonistic coevolution between the sexes may be played out across reproductive stages. In Tribolium, males' olfactory attractiveness is positively correlated with both insemination success and paternity share, suggesting consistent selection across different reproductive stages. Similar studies across sequential reproductive stages are needed in other taxa to provide a more integrative view of sexual selection.
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Cheng, Ren-Chung; Zhang, Shichang; Chen, Yu-Chun; Lee, Chia-Yi; Chou, Yi-Ling; Ye, Hui-Ying; Piorkowski, Dakota; Liao, Chen-Pan; Tso, I-Min
2017-06-15
While molting occurs in the development of many animals, especially arthropods, post-maturity molting (PMM, organisms continue to molt after sexual maturity) has received little attention. The mechanism of molting has been studied intensively; however, the mechanism of PMM remains unknown although it is suggested to be crucial for the development of body size. In this study, we investigated factors that potentially induce PMM in the golden orb-web spider Nephila pilipes , which has the greatest degree of sexual dimorphism among terrestrial animals. We manipulated the mating history and the nutrient consumption of the females to examine whether they affect PMM. The results showed that female spiders under low nutrition were more likely to molt as adults, and mating had no significant influence on the occurrence of PMM. Moreover, spiders that underwent PMM lived longer than those that did not and their body sizes were significantly increased. Therefore, we concluded that nutritional condition rather than mating history affect PMM. © 2017. Published by The Company of Biologists Ltd.
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Lentini, A; Mura, A; Muscas, E; Nuvoli, M T; Cocco, A
2018-04-01
The effect of increasing mating delay on the reproductive performance and population growth rates of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), was investigated under laboratory conditions. Virgin females were mated at 1, 3, 5, 7, 14, 21 and 28 days after emergence and reproductive and life table parameters were estimated. The pre-oviposition period (number of days between mating and the onset of oviposition) significantly decreased in females mated within 7 days, whereas females mated at older ages showed equivalent pre-oviposition periods (7 days, as shorter delays in mating did not reduce the population growth rates.
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Caddigan, Sara C; Barkauskas, Rima T; Sparkes, Timothy C
2014-11-01
The acanthocephalan parasite Acanthocephalus dirus infects the freshwater isopod Caecidotea intermedius as an intermediate host before completing its life cycle in a fish. Male C. intermedius infected by A. dirus parasites are less likely to engage in mating behavior than uninfected males but there is a significant intra-population variation in the occurrence of this behavioral change. Previous studies on uninfected isopods have shown that glycogen content is a predictor of male mating behavior and we examined whether the intra-population variation in the mating behavior of infected male C. intermedius could be explained by this relationship. A field-based behavioral experiment was used to quantify intra-population variation in male mating behavior, which showed that 50% of infected males were responsive to females and 50% were not responsive. Biochemical analysis of responsive and non-responsive males revealed that glycogen content was a predictor of the mating behavior for uninfected males but was not a predictor of mating behavior for infected males. For infected males, parasite intensity was a predictor of mating behavior. Males that contained more A. dirus parasites were less likely to undergo modification of mating behavior. We propose that the intra-population variation in the mating behavior of infected C. intermedius identified in nature was not mediated by host condition.
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Free mate choice does not influence reproductive success in humans.
Sorokowski, Piotr; Groyecka, Agata; Karwowski, Maciej; Manral, Upma; Kumar, Amit; Niemczyk, Agnieszka; Marczak, Michalina; Misiak, Michał; Sorokowska, Agnieszka; Huanca, Thomas; Conde, Esther; Wojciszke, Bogdan; Pawłowski, Bogusław
2017-08-31
The effect of free mate choice on the relative magnitude of fitness benefits has been examined among various species. The majority of the data show significant fitness benefits of mating with partners of an individual's own choice, highlighting elevated behavioral compatibility between partners with free mate choice. Similarities between humans and other species that benefit from free mate choice led us to hypothesize that it also confers reproductive benefits in Homo sapiens. To test this hypothesis, we conducted a study among three indigenous societies-the Tsimane', Yali, and Bhotiya-who employ natural birth control. In all three samples, we compared the marriages arranged by parents with the non-arranged ones in terms of number of offspring. Here, we show that there were no significant relationships between type of marriage and the total number of alive children and number of dead children among the three sampled groups. The presented study is the first to date to examine the fitness benefits of free mate choice in humans. In discussion we present limitations of our research and discuss the possibility of love having a beneficial influence in terms of the number of offspring.
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The use of ultrasound for communication by the big brown bat (Eptesicus fuscus)
NASA Astrophysics Data System (ADS)
Grilliot, Matthew E.
2007-12-01
Communication signals are important regulators of mating behavior in many animals. Various pre- and post-copulatory mechanisms have been suggested to play a role in the reproductive success and mating strategies of many mammals. Recent studies have cited sperm competition as a possible post-copulatory mechanism of selection in bats, but few studies have examined which pre-copulatory mechanisms influence mate selection. Although it is generally accepted that bats emit vocalizations that function for communication purposes as well as the more universally recognized echolocation function, there is lack of actual empirical support for this idea. In this dissertation, I test the hypothesis that ultrasonic vocalizations of big brown bats are sexually dimorphic and differ contextually in the mating season. I used playback experiments to test the response of male and female big brown bats to variations in ultrasonic vocalizations of the opposite sex and to determine if ultrasonic vocalizations are used for mate selection. My data suggest that males were likely to select ultrasonic vocalization of frequently copulating females, but females did not select ultrasonic vocalizations of frequently copulating males over infrequently copulating males. These results suggest that mate selection of male big brown bats is influenced by ultrasonic vocalizations of females.
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Edwards, Mark A; Derocher, Andrew E
2015-02-01
In comparison to core populations, peripheral populations have low density and recruitment, and are subject to different selective pressures, such as environmental conditions, food type and availability, predation, disease, etc., which may result in behavioural modifications to mating. We test the roam-to-mate hypothesis for a peripheral population of grizzly bears (Ursus arctos) at the northern extent of their North American range, in Canada's Arctic. If bears are roaming-to-mate, we predicted greater range size and daily displacement, and more linear movements for receptive animals during the mating period compared to post-mating. In contrast to our predictions, we found that in general range size and displacement increased from mating to post-mating regardless of reproductive status. When considered across both periods, females with cubs-of-the-year had smaller range use metrics than other reproductive groups, which we attribute to a counter-strategy against sexually selected infanticide and the reduced mobility of cubs. Linearity of movements remained near zero during both periods across all groups, suggesting tortuous movements more characteristic of foraging than of mate-searching. We suggest that for this population, finding quality habitat takes precedence over mate-searching in this marginal Arctic landscape. Alternatively, a more monogamous mating system and sequestering behaviour may have obscured movement differences between the two periods. The behavioural differences in mating that we observed from what is typical of core populations may reflect local adaptation to marginal conditions and could benefit the species in the face of ongoing environmental change. Copyright © 2014 Elsevier B.V. All rights reserved.
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Rupp, J C; Woolhouse, M E
1999-12-01
Studies of inbreeding and outcrossing have traditionally concentrated on matings within populations. The influence of geographical origin on mate choice in animals from different populations has received less attention. We investigated whether planorbid snails mated preferentially within their own population or with snails from other populations. Snails from three Biomphalaria pfeifferi strains and three B. glabrata strains were allowed to mate with conspecifics in the laboratory. We recorded their matings at night using time-lapse video. When they could choose between sympatric and allopatric snails, Biomphalaria snails significantly preferred the former: snails of each population mated more often with sympatric than with allopatric snails. This tendency to avoid outcrossing may indicate that, in some species, local adaptations can be more valuable than genetic novelties. Copyright 1999 The Association for the Study of Animal Behaviour.
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Avise, John C.; Liu, Jin-Xian
2010-01-01
We construct a verbal and graphical theory (the “fecundity-limitation hypothesis”) about how constraints on the brooding space for embryos probably truncate individual fecundity in male-pregnant and female-pregnant species in ways that should differentially influence selection pressures for multiple mating by males or by females. We then review the empirical literature on genetically deduced rates of multiple mating by the embryo-brooding parent in various fish species with three alternative categories of pregnancy: internal gestation by males, internal gestation by females, and external gestation (in nests) by males. Multiple mating by the brooding gender was common in all three forms of pregnancy. However, rates of multiple mating as well as mate numbers for the pregnant parent averaged higher in species with external as compared with internal male pregnancy, and also for dams in female-pregnant species versus sires in male-pregnant species. These outcomes are all consistent with the theory that different types of pregnancy have predictable consequences for a parent's brood space, its effective fecundity, its opportunities and rewards for producing half-sib clutches, and thereby its exposure to selection pressures for seeking multiple mates. Overall, we try to fit these fecundity-limitation phenomena into a broader conceptual framework for mating-system evolution that also includes anisogamy, sexual-selection gradients, parental investment, and other selective factors that can influence the relative proclivities of males versus females to seek multiple sexual partners. PMID:20956296
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Carry-over effects of the social environment on future divorce probability in a wild bird population
Culina, Antica; Hinde, Camilla A.; Sheldon, Ben C.
2015-01-01
Initial mate choice and re-mating strategies (infidelity and divorce) influence individual fitness. Both of these should be influenced by the social environment, which determines the number and availability of potential partners. While most studies looking at this relationship take a population-level approach, individual-level responses to variation in the social environment remain largely unstudied. Here, we explore carry-over effects on future mating decisions of the social environment in which the initial mating decision occurred. Using detailed data on the winter social networks of great tits, we tested whether the probability of subsequent divorce, a year later, could be predicted by measures of the social environment at the time of pairing. We found that males that had a lower proportion of female associates, and whose partner ranked lower among these, as well as inexperienced breeders, were more likely to divorce after breeding. We found no evidence that a female's social environment influenced the probability of divorce. Our findings highlight the importance of the social environment that individuals experience during initial pair formation on later pairing outcomes, and demonstrate that such effects can be delayed. Exploring these extended effects of the social environment can yield valuable insights into processes and selective pressures acting upon the mating strategies that individuals adopt. PMID:26468239
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Wright, Sarah; Fokidis, H Bobby
2016-09-01
Perturbations in an organism's environment can induce significant shifts in hormone secretory patterns. In this context, the glucocorticoid (GC) steroids secreted by the adrenal cortex have received much attention from ecologists and behaviorists due to their role in the vertebrate stress response. Adrenal GCs, such as corticosterone (CORT), are highly responsive to instability in environmental and social conditions. However, little is understood about how adrenal dehydroepiandrosterone (DHEA) is influenced by changing conditions. We conducted field experiments to determine how circulating CORT and DHEA vary during restraint stress in the male northern cardinals (Cardinalis cardinalis). Specifically, we examined how four different changes in the physical (urbanization and food availability) and social (territorial conflict, distress of a mate) environment affect CORT and DHEA levels. The majority of cardinals responded to restraint stress by increasing and decreasing CORT and DHEA, respectively, however this depended on sampling context. Cardinals sampled from urban habitats had both lower initial and restraint stress CORT concentrations, but a comparable DHEA pattern to those sampled from a forest. Supplementing food to territorial males did not alter circulating initial DHEA or CORT concentrations nor did it change the response to restraint stress when compared to unsupplemented controls. Exposing cardinals to varying durations of song playback, which mimics a territorial intrusion, did not affect CORT levels, but did attenuate the DHEA response to restraint stress. Examining a larger dataset of males captured before, after or at the same time as their female mate, allowed us to address how the stress of a captured mate affected the male's CORT and DHEA response. Males showed elevated initial and restraint CORT and DHEA when their female mate was captured first. Taken together, these data demonstrate that both CORT and DHEA secretion patterns depends on environmental, and particularly current social conditions. Copyright © 2016 Elsevier Inc. All rights reserved.
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Environmental change mediates mate choice for an extended phenotype, but not for mate quality.
Head, Megan L; Fox, Rebecca J; Barber, Iain
2017-01-01
Sexual cues, including extended phenotypes, are expected to be reliable indicators of male genetic quality and/or provide information on parental quality. However, the reliability of these cues may be dependent on stability of the environment, with heterogeneity affecting how selection acts on such traits. Here, we test how environmental change mediates mate choice for multiple sexual traits, including an extended phenotype--the structure of male-built nests - in stickleback fish. First, we manipulated the dissolved oxygen (DO) content of water to create high or low DO environments in which male fish built nests. Then we recorded the mate choice of females encountering these males (and their nests), under either the same or reversed DO conditions. Males in high DO environments built more compact nests than those in low DO conditions and males adjusted their nest structure in response to changing conditions. Female mate choice for extended phenotype (male nests) was environmentally dependent (females chose more compact nests in high DO conditions), while female choice for male phenotype was not (females chose large, vigorous males regardless of DO level). Examining mate choice in this dynamic context suggests that females evaluate the reliability of multiple sexual cues, taking into account environmental heterogeneity. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.
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Both Geography and Ecology Contribute to Mating Isolation in Guppies
Schwartz, Amy K.; Weese, Dylan J.; Bentzen, Paul; Kinnison, Michael T.; Hendry, Andrew P.
2010-01-01
Local adaptation to different environments can promote mating isolation – either as an incidental by-product of trait divergence, or as a result of selection to avoid maladaptive mating. Numerous recent empirical examples point to the common influence of divergent natural selection on speciation based largely on evidence of strong pre-mating isolation between populations from different habitat types. Accumulating evidence for natural selection's influence on speciation is therefore no longer a challenge. The difficulty, rather, is in determining the mechanisms involved in the progress of adaptive divergence to speciation once barriers to gene flow are already present. Here, we present results of both laboratory and field experiments with Trinidadian guppies (Poecilia reticulata) from different environments, who do not show complete reproductive isolation despite adaptive divergence. We investigate patterns of mating isolation between populations that do and do not exchange migrants and show evidence for both by-product and reinforcement mechanisms depending on female ecology. Specifically, low-predation females discriminate against all high-predation males thus implying a by-product mechanism, whereas high-predation females only discriminate against low-predation males from further upstream in the same river, implying selection to avoid maladaptive mating. Our study thus confirms that mechanisms of adaptive speciation are not necessarily mutually exclusive and uncovers the complex ecology-geography interactions that underlie the evolution of mating isolation in nature. PMID:21179541
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The Putative Son's Attractiveness Alters the Perceived Attractiveness of the Putative Father.
Prokop, Pavol
2015-08-01
A body of literature has investigated female mate choice in the pre-mating context (pre-mating sexual selection). Humans, however, are long-living mammals forming pair-bonds which sequentially produce offspring. Post-mating evaluations of a partner's attractiveness may thus significantly influence the reproductive success of men and women. I tested herein the theory that the attractiveness of putative sons provides extra information about the genetic quality of fathers, thereby influencing fathers' attractiveness across three studies. As predicted, facially attractive boys were more frequently attributed to attractive putative fathers and vice versa (Study 1). Furthermore, priming with an attractive putative son increased the attractiveness of the putative father with the reverse being true for unattractive putative sons. When putative fathers were presented as stepfathers, the effect of the boy's attractiveness on the stepfather's attractiveness was lower and less consistent (Study 2). This suggests that the presence of an attractive boy has the strongest effect on the perceived attractiveness of putative fathers rather than on non-fathers. The generalized effect of priming with beautiful non-human objects also exists, but its effect is much weaker compared with the effects of putative biological sons (Study 3). Overall, this study highlighted the importance of post-mating sexual selection in humans and suggests that the heritable attractive traits of men are also evaluated by females after mating and/or may be used by females in mate poaching.
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Guo, Qingke; Feng, Linlin; Wang, Mingming
2017-04-01
Human's preferences for altruistic mates have been confirmed by many researchers. Under the deep influence of Confucianism that authorised more parental control over offspring's mate selection, Chinese people's mating strategies and mate preferences may be different from what the evolutionary psychologists have suggested. This study used the Q-sort technique to assess the roles of altruistic traits in mate selection and personal advertisement. A total of 200 university students participated in the Q-sort procedures and were asked to sort 50 traits (among which altruistic traits were mixed) according to their importance when choosing (or advertising to) a long-term (LT) or a short-term (ST) mate. Our findings were quite different from prior studies. When Chinese participants chose a mate or advertised themselves to a potential mate, kin altruism was considered to be the most important trait; altruistic traits were more preferred by males than by females and females tended to advertise themselves as more altruistic; preferences for altruistic traits showed no difference between LT and ST mate selections (or between personal advertisement to a LT and a ST mate). © 2015 International Union of Psychological Science.
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NASA Astrophysics Data System (ADS)
Wu, Daheng; Ren, Siming; Pu, Jibin; Lu, Zhibin; Zhang, Guangan; Wang, Liping
2018-05-01
The tribological behaviors of hydrogenated DLC film sliding against Al2O3, ZrO2, Si3N4 and WC mating balls have been comparatively investigated by a ball-on-disk tribometer at 150 °C under helium and air (RH = 6%) conditions. The results showed that the mating material influenced the friction and wear behavior remarkably in helium atmosphere, where the wear rates were in inversely proportional to the friction coefficients (COF) of those tribo-pairs. Compared to the tests in helium, the tribological performance of DLC film significantly improved in air. Scanning electron microscope (SEM) and Raman spectroscopy were performed to study the friction behavior and wear mechanism of the film under different conditions. It suggested that the severe abrasion was caused by the strong interaction between the tribo-pairs in helium atmosphere at 150 °C, whereas the sufficient passivation of the dangling bonds of carbon atoms at sliding interface by chemically active molecules, such as water and oxygen, dominated the ultralow friction under air condition. Meanwhile, Hertz analysis was used to further elucidate the frictional mechanism of DLC film under helium and air conditions. It showed that the coefficient of friction was consistent with the varied tendency of the contact radius, namely, higher friction coefficient corresponded to the larger contact radius, which was the same with the relationship between the wear rate and the contact pressure. All of the results made better understanding of the essential mechanism of hydrogenated DLC film sliding against different pairs, which were able to guide the further application of DLC film in the industrial fields of helium atmosphere.
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Rao, Li-Lin; Wang, Xiao-Tian; Li, Shu
2015-01-01
We examined resource allocation priorities in the framework of an updated Maslow hierarchy of fundamental human needs. In Experiment 1, the participants in the food abundance priming condition viewing photos of high-calorie food allocated more money to savings than to spending. However, the participants preferred spending to savings under the condition of mating availability priming with romantic photographs. In Experiment 2, before and after drinking either water or a sugary beverage, fasting participants rated photos of a conversation between a man and a woman. Water drinking lowered the rating scores of mating intentions as well as blood glucose (BG) levels. The sugary drink buffered this decline in sexual perceptivity. Overall, the change in BG levels was positively associated with changes in the ratings of mating intentions but was not associated with other likelihood ratings. These results suggest that both external cues of food and mating resources and internal BG fluctuation regulate the cognitive priority of physiological needs vs. mate acquisition and retention. PMID:25610412
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Rao, Li-Lin; Wang, Xiao-Tian; Li, Shu
2014-01-01
We examined resource allocation priorities in the framework of an updated Maslow hierarchy of fundamental human needs. In Experiment 1, the participants in the food abundance priming condition viewing photos of high-calorie food allocated more money to savings than to spending. However, the participants preferred spending to savings under the condition of mating availability priming with romantic photographs. In Experiment 2, before and after drinking either water or a sugary beverage, fasting participants rated photos of a conversation between a man and a woman. Water drinking lowered the rating scores of mating intentions as well as blood glucose (BG) levels. The sugary drink buffered this decline in sexual perceptivity. Overall, the change in BG levels was positively associated with changes in the ratings of mating intentions but was not associated with other likelihood ratings. These results suggest that both external cues of food and mating resources and internal BG fluctuation regulate the cognitive priority of physiological needs vs. mate acquisition and retention.
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ASSORTATIVE MATING CAN IMPEDE OR FACILITATE FIXATION OF UNDERDOMINANT ALLELES
NEWBERRY, MITCHELL G; MCCANDLISH, DAVID M; PLOTKIN, JOSHUA B
2017-01-01
Underdominant mutations have fixed between divergent species, yet classical models suggest that rare underdominant alleles are purged quickly except in small or subdivided populations. We predict that underdominant alleles that also influence mate choice, such as those affecting coloration patterns visible to mates and predators alike, can fix more readily. We analyze a mechanistic model of positive assortative mating in which individuals have n chances to sample compatible mates. This one-parameter model naturally spans random mating (n =1) and complete assortment (n → ∞), yet it produces sexual selection whose strength depends non-monotonically on n. This sexual selection interacts with viability selection to either inhibit or facilitate fixation. As mating opportunities increase, underdominant alleles fix as frequently as neutral mutations, even though sexual selection and underdominance independently each suppress rare alleles. This mechanism allows underdominant alleles to fix in large populations and illustrates how life history can affect evolutionary change. PMID:27497738
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Bargielowski, I E; Lounibos, L P; Shin, D; Smartt, C T; Carrasquilla, M C; Henry, A; Navarro, J C; Paupy, C; Dennett, J A
2015-12-01
Aedes aegypti and Aedes albopictus, two important vectors of the dengue and chikungunya viruses to humans, often come in contact in their invasive ranges. In these circumstances, a number of factors are thought to influence their population dynamics, including resource competition among the larval stages, prevailing environmental conditions and reproductive interference in the form of satyrization. As the distribution and abundance of Ae. aegypti and Ae. albopictus have profound epidemiological implications, understanding the competitive interactions that influence these patterns in nature is important. While evidence for resource competition and environmental factors had been gathered from the field, the evidence for reproductive interference, though strongly inferred through laboratory trials, remained sparse (one small-scale field trial). In this paper we demonstrate that low rates (1.12-3.73%) of interspecific mating occur in nature among populations of these species that have co-existed sympatrically from 3 to 150yrs. Finally this report contributes a new species-specific primer set for identifying the paternity of sperm extracted from field collected specimens. Copyright © 2015 Elsevier B.V. All rights reserved.
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Watkins, Christopher D
2012-08-01
Changing circumstances alter the costs and benefits of choosing different mates and are thought to be reflected in women's mate preferences. Indeed, several lines of reasoning, and some prior studies, suggest that individual differences in women's preferences for cues of men's underlying health will be more apparent among partnered women than among unpartnered women. The current study shows that preferences for male faces with masculine shape cues, characteristics that are thought to signal men's underlying health, are positively correlated with partnered, but not unpartnered, women's reported reproductive ambition (i.e., their desire to become pregnant). These findings (1) present new evidence for systematic variation in women's mating strategies, (2) suggest that partnership status may be important for potentially adaptive variation in women's mate preferences, and (3) suggest that reproductive ambition may influence women's mate preferences. Alternative explanations for these findings, focusing on the possible effects of a range of variables that may be correlated with reproductive ambition in partnered women and influence their masculinity preferences, are also discussed. ©2011 The British Psychological Society.
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Setchell, Joanna M; Abbott, Kristin M; Gonzalez, Jean-Paul; Knapp, Leslie A
2013-10-01
A large body of evidence suggests that major histocompatibility complex (MHC) genotype influences mate choice. However, few studies have investigated MHC-mediated post-copulatory mate choice under natural, or even semi-natural, conditions. We set out to explore this question in a large semi-free-ranging population of mandrills (Mandrillus sphinx) using MHC-DRB genotypes for 127 parent-offspring triads. First, we showed that offspring MHC heterozygosity correlates positively with parental MHC dissimilarity suggesting that mating among MHC dissimilar mates is efficient in increasing offspring MHC diversity. Second, we compared the haplotypes of the parental dyad with those of the offspring to test whether post-copulatory sexual selection favored offspring with two different MHC haplotypes, more diverse gamete combinations, or greater within-haplotype diversity. Limited statistical power meant that we could only detect medium or large effect sizes. Nevertheless, we found no evidence for selection for heterozygous offspring when parents share a haplotype (large effect size), genetic dissimilarity between parental haplotypes (we could detect an odds ratio of ≥1.86), or within-haplotype diversity (medium-large effect). These findings suggest that comparing parental and offspring haplotypes may be a useful approach to test for post-copulatory selection when matings cannot be observed, as is the case in many study systems. However, it will be extremely difficult to determine conclusively whether post-copulatory selection mechanisms for MHC genotype exist, particularly if the effect sizes are small, due to the difficulty in obtaining a sufficiently large sample. © 2013 Wiley Periodicals, Inc.
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Lancaster, Lesley T; McAdam, Andrew G; Hipsley, Christy A; Sinervo, Barry R
2014-08-01
Genetically determined polymorphisms incorporating multiple traits can persist in nature under chronic, fluctuating, and sometimes conflicting selection pressures. Balancing selection among morphs preserves equilibrium frequencies, while correlational selection maintains favorable trait combinations within each morph. Under negative frequency-dependent selection, females should mate (often disassortatively) with rare male morphotypes to produce conditionally fit offspring. Conversely, under correlational selection, females should mate assortatively to preserve coadapted gene complexes and avoid ontogenetic conflict. Using controlled breeding designs, we evaluated consequences of assortative mating patterns in color-polymorphic side-blotched lizards (Uta stansburiana), to identify conflict between these sources of selection. Females who mated disassortatively, and to conditionally high-quality males in the context of frequency-dependent selection, experienced highest fertility rates. In contrast, assortatively mated females experienced higher fetal viability rates. The trade-off between fertility and egg viability resulted in no overall fitness benefit to either assortative or disassortative mating patterns. These results suggest that ongoing conflict between correlational and frequency dependent selection in polymorphic populations may generate a trade-off between rare-morph advantage and phenotypic integration and between assortative and disassortative mating decisions. More generally, interactions among multiple sources of diversity-promoting selection can alter adaptations and dynamics predicted to arise under any of these regimes alone.
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Functional pleiotropy and mating system evolution in plants: frequency-independent mating.
Jordan, Crispin Y; Otto, Sarah P
2012-04-01
Mutations that alter the morphology of floral displays (e.g., flower size) or plant development can change multiple functions simultaneously, such as pollen export and selfing rate. Given the effect of these various traits on fitness, pleiotropy may alter the evolution of both mating systems and floral displays, two characters with high diversity among angiosperms. The influence of viability selection on mating system evolution has not been studied theoretically. We model plant mating system evolution when a single locus simultaneously affects the selfing rate, pollen export, and viability. We assume frequency-independent mating, so our model characterizes prior selfing. Pleiotropy between increased viability and selfing rate reduces opportunities for the evolution of pure outcrossing, can favor complete selfing despite high inbreeding depression, and notably, can cause the evolution of mixed mating despite very high inbreeding depression. These results highlight the importance of pleiotropy for mating system evolution and suggest that selection by nonpollinating agents may help explain mixed mating, particularly in species with very high inbreeding depression. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
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Barman, C; Singh, V K; Das, S; Tandon, R
2018-05-01
Reproductive success of a plant species is largely influenced by the outcome of mating pattern in a population. It is believed that a significantly larger proportion of animal-pollinated plants have evolved a mixed-mating strategy, the extent of which may vary among species. It is thus pertinent to investigate the key contributors to mating success, especially to identify the reproductive constraints in depauperate populations of threatened plant species. We examined the contribution of floral architecture, pollination mechanism and breeding system on the extent of outcrossing rate in a near-threatened tree species, Wrightia tomentosa. The breeding system was ascertained from controlled pollination experiments. In order to determine outcrossing rate, 60 open-pollinated progeny were analysed using an AFLP markers. Although the trees are self-compatible, herkogamy and compartmentalisation of pollen and nectar in different chambers of the floral tube effectively prevent spontaneous autogamy. Pollination is achieved through specialised interaction with moths. Differential foraging behaviour of settling moths and hawkmoths leads to different proportions of geitonogamous and xenogamous pollen on the stigma. However, most open-pollinated progeny were the result of xenogamy (outcrossing rate, tm = 0.68). The study shows that floral contrivances and pollination system have a strong influence on mating pattern. The differential foraging behaviour of the pollinators causes deposition of a mixture of self- and cross-pollen to produce a mixed brood. Inbreeding depression and geitonogamy appear to play a significant role in sustaining mixed mating in this species. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.
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Sexual conflict arising from extrapair matings in birds.
Chaine, Alexis S; Montgomerie, Robert; Lyon, Bruce E
2015-01-20
The discovery that extrapair copulation (EPC) and extrapair paternity (EPP) are common in birds led to a paradigm shift in our understanding of the evolution of mating systems. The prevalence of extrapair matings in pair-bonded species sets the stage for sexual conflict, and a recent focus has been to consider how this conflict can shape variation in extrapair mating rates. Here, we invert the causal arrow and consider the consequences of extrapair matings for sexual conflict. Extrapair matings shift sexual conflict from a simple two-player (male vs. female) game to a game with three or more players, the nature of which we illustrate with simple diagrams that highlight the net costs and benefits of extrapair matings to each player. This approach helps identify the sorts of traits that might be under selection because of sexual conflict. Whether EPP is driven primarily by the extrapair male or the within-pair female profoundly influences which players are in conflict, but the overall pattern of conflict varies little among different mating systems. Different aspects of conflict are manifest at different stages of the breeding cycle and can be profitably considered as distinct episodes of selection caused by conflict. This perspective is illuminating both because conflict between specific players can change across episodes and because the traits that evolve to mediate conflict likely differ between episodes. Although EPP clearly leads to sexual conflict, we suggest that the link between sexual conflict and multiple paternity might be usefully understood by examining how deviations from lifetime sexual monogamy influence sexual conflict. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.
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Sexual Conflict Arising from Extrapair Matings in Birds
Chaine, Alexis S.; Montgomerie, Robert; Lyon, Bruce E.
2015-01-01
The discovery that extrapair copulation (EPC) and extrapair paternity (EPP) are common in birds led to a paradigm shift in our understanding of the evolution of mating systems. The prevalence of extrapair matings in pair-bonded species sets the stage for sexual conflict, and a recent focus has been to consider how this conflict can shape variation in extrapair mating rates. Here, we invert the causal arrow and consider the consequences of extrapair matings for sexual conflict. Extrapair matings shift sexual conflict from a simple two-player (male vs. female) game to a game with three or more players, the nature of which we illustrate with simple diagrams that highlight the net costs and benefits of extrapair matings to each player. This approach helps identify the sorts of traits that might be under selection because of sexual conflict. Whether EPP is driven primarily by the extrapair male or the within-pair female profoundly influences which players are in conflict, but the overall pattern of conflict varies little among different mating systems. Different aspects of conflict are manifest at different stages of the breeding cycle and can be profitably considered as distinct episodes of selection caused by conflict. This perspective is illuminating both because conflict between specific players can change across episodes and because the traits that evolve to mediate conflict likely differ between episodes. Although EPP clearly leads to sexual conflict, we suggest that the link between sexual conflict and multiple paternity might be usefully understood by examining how deviations from lifetime sexual monogamy influence sexual conflict. PMID:25605708
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The Role of Cuticular Pheromones in Courtship Conditioning of "Drosophila" Males
ERIC Educational Resources Information Center
Siwicki, Kathleen K.; Riccio, Paul; Ladewski, Lisa; Marcillac, Fabrice; Dartevelle, Laurence; Cross, Stephanie A.; Ferveur, Jean-Francois
2005-01-01
Courtship conditioning is an associative learning paradigm in "Drosophila melanogaster," wherein male courtship behavior is modified by experience with unreceptive, previously mated females. While the training experience with mated females involves multiple sensory and behavioral interactions, the authors hypothesized that female cuticular…
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Landry, C; Garant, D; Duchesne, P; Bernatchez, L
2001-06-22
According to the theory of mate choice based on heterozygosity, mates should choose each other in order to increase the heterozygosity of their offspring. In this study, we tested the 'good genes as heterozygosity' hypothesis of mate choice by documenting the mating patterns of wild Atlantic salmon (Salmo salar) using both major histocompatibility complex (MHC) and microsatellite loci. Specifically, we tested the null hypotheses that mate choice in Atlantic salmon is not dependent on the relatedness between potential partners or on the MHC similarity between mates. Three parameters were assessed: (i) the number of shared alleles between partners (x and y) at the MHC (M(xy)), (ii) the MHC amino-acid genotypic distance between mates' genotypes (AA(xy)), and (iii) genetic relatedness between mates (r(xy)). We found that Atlantic salmon choose their mates in order to increase the heterozygosity of their offspring at the MHC and, more specifically, at the peptide-binding region, presumably in order to provide them with better defence against parasites and pathogens. This was supported by a significant difference between the observed and expected AA(xy) (p = 0.0486). Furthermore, mate choice was not a mechanism of overall inbreeding avoidance as genetic relatedness supported a random mating scheme (p = 0.445). This study provides the first evidence that MHC genes influence mate choice in fish.
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49 CFR 179.14 - Coupler vertical restraint system.
Code of Federal Regulations, 2011 CFR
2011-10-01
... system shall be tested under the following conditions: (1) The test coupler shall be tested with a mating coupler (or simulated coupler) having only frictional vertical force resistance at the mating interface; or a mating coupler (or simulated coupler) having the capabilities described in paragraph (a) of this...
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Genetic effects on mating success and partner choice in a social mammal
Tung, Jenny; Charpentier, Marie JE; Mukherjee, Sayan; Altmann, Jeanne; Alberts, Susan C
2012-01-01
Mating behavior has profound consequences for two phenomena – individual reproductive success and the maintenance of species boundaries – that contribute to evolutionary processes. Studies of mating behavior in relation to individual reproductive success are common in many species, but studies of mating behavior in relation to genetic variation and species boundaries are less commonly conducted in socially complex species. Here, we leveraged extensive observations of a wild yellow baboon (Papio cynocephalus) population that has experienced recent gene flow from a close sister taxon, the anubis baboon (Papio anubis), to examine how admixture-related genetic background affects mating behavior. We identified novel effects of genetic background on mating patterns, including an advantage accruing to anubis-like males and assortative mating among both yellow-like and anubis-like pairs. These genetic effects acted alongside social dominance rank, inbreeding avoidance, and age to produce highly nonrandom mating patterns. Our results suggest that this population may be undergoing admixture-related evolutionary change, driven in part by nonrandom mating. However, the strength of the genetic effects is mediated by behavioral plasticity and social interactions, emphasizing the strong influence of social context on mating behavior in socially complex species. PMID:22673655
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Mating system and ploidy influence levels of inbreeding depression in Clarkia (Onagraceae).
Barringer, Brian C; Geber, Monica A
2008-05-01
Inbreeding depression is the reduction in offspring fitness associated with inbreeding and is thought to be one of the primary forces selecting against the evolution of self-fertilization. Studies suggest that most inbreeding depression is caused by the expression of recessive deleterious alleles in homozygotes whose frequency increases as a result of self-fertilization or mating among relatives. This process leads to the selective elimination of deleterious alleles such that highly selfing species may show remarkably little inbreeding depression. Genome duplication (polyploidy) has also been hypothesized to influence levels of inbreeding depression, with polyploids expected to exhibit less inbreeding depression than diploids. We studied levels of inbreeding depression in allotetraploid and diploid species of Clarkia (Onagraceae) that vary in mating system (each cytotype was represented by an outcrossing and a selfing species). The outcrossing species exhibited more inbreeding depression than the selfing species for most fitness components and for two different measures of cumulative fitness. In contrast, though inbreeding depression was generally lower for the polyploid species than for the diploid species, the difference was statistically significant only for flower number and one of the two measures of cumulative fitness. Further, we detected no significant interaction between mating system and ploidy in determining inbreeding depression. In sum, our results suggest that a taxon's current mating system is more important than ploidy in influencing levels of inbreeding depression in natural populations of these annual plants.
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Zhu, Dao-Hong; Cui, Shuang-Shuang; Fan, Yong-Sheng; Liu, Zhiwei
2013-04-01
To understand the adaptive strategies of the overwintering adults of Stenocatantops splendens, the mechanism of maintenance and termination of the reproductive diapause, the variation in mortality between overwintering females and males, and the mating strategy of the males were investigated. The results indicated that the adult reproductive diapause in natural conditions was mainly regulated by photoperiod in the fall - long photoperiods promoted reproductive development and short photoperiods maintained reproductive diapause, and the sensitivity of the overwintering adults to photoperiod was over before the end of the winter. When transferred from natural conditions to controlled laboratory conditions on dates from September through February, pre-oviposition became increasingly shorter with increasingly deferred transfer dates regardless of photoperiod conditions. The adults treated with low temperature for 30 days in September through November had significantly shorter pre-oviposition, suggesting that low temperatures in winter had an important role in the termination of reproductive diapause. The female had a significantly lower supercooling point than the male, which was related to their lower mortality after winter. In addition, observations of wild populations of the species indicated that mating behavior prior to winter and the duration of pre-mating period were not affected by photoperiod; mating and sperm transfer were mostly completed by November. Compared with females only mating before winter, females mating in the spring had shorter life span, longer pre-oviposition, lower hatching rate and laid fewer egg pods while showing no significant difference with regard to ovipositional interval, per pod number of eggs and nymph dry weight. © 2012 The Authors Insect Science © 2012 Institute of Zoology, Chinese Academy of Sciences.
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Optimal level of inbreeding in the common lizard.
Richard, M; Losdat, S; Lecomte, J; de Fraipont, M; Clobert, J
2009-08-07
Mate choice with regard to genetic similarity has been rarely considered as a dynamic process. We examined this possibility in breeding populations of the common lizard (Lacerta vivipara) kept for several years in semi-natural conditions. We investigated whether they displayed a pattern of mate choice according to the genetic similarity and whether it was context-dependent. Mate choice depended on genetic similarity with the partner and also on age and condition. There was no systematic avoidance of inbreeding. Females of intermediate ages, more monogamous, did not mate with genetically similar partners, whereas younger and older females, more polyandrous, did but highest clutch proportions were associated with intermediate values of pair-relatedness. These results indicate dynamic mate choice, suggesting that individuals of different phenotypes select their partners in different ways according to their genetic similarity. We consider our results in the light of diverse and apparently contradictory theories concerning genetic compatibility, and particularly, optimal inbreeding and inclusive fitness.
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Marcela, P; Hassan, A Abu; Hamdan, A; Dieng, H; Kumara, T K
2015-12-01
Mating behavior between Aedes aegypti and Ae. albopictus, established colony strains were examined under laboratory conditions (30-cm(3) screened cages) for 5 consecutive days. The effect of selected male densities (30, 20, 10) and female density (20) on the number of swarming, mating pairs, eggs produced, and inseminated females were evaluated. Male densities significantly increased swarming behavior, mating pairs, and egg production of heterospecific females, but female insemination was reduced. Aedes aegypti males mate more readily with heterospecific females than do Ae. albopictus males. The current study suggests that Ae. aegypti males were not species-specific in mating, and if released into the field as practiced in genetically modified mosquito techniques, they may mate with both Ae. aegypti and Ae. albopictus females, hence reducing populations of both species by producing infertile eggs.
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Social support influences preferences for feminine facial cues in potential social partners.
Watkins, Christopher D; DeBruine, Lisa M; Little, Anthony C; Jones, Benedict C
2012-01-01
Most previous studies of individual differences in women's and men's preferences for sexually dimorphic physical characteristics have focused on the importance of mating-related factors for judgments of opposite-sex individuals. Although studies have suggested that people may show stronger preferences for feminine individuals of both sexes under conditions where social support may be at a premium (e.g., during phases of the menstrual cycle where raised progesterone prepares women's bodies for pregnancy), these studies have not demonstrated that perceptions of available social support directly influence femininity preferences. Here we found that (1) women and men randomly allocated to low social support priming conditions demonstrated stronger preferences for feminine shape cues in own- and opposite-sex faces than did individuals randomly allocated to high social support priming conditions and (2) that people perceived men and women displaying feminine characteristics as more likely to provide them with high-quality social support than those displaying relatively masculine characteristics. Together, these findings suggest that social support influences face preferences directly, potentially implicating facultative responses whereby people increase their preferences for pro-social individuals under conditions of low social support.
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Prokop, Pavol; Fedor, Peter
2013-01-01
Human body morphology is thought to be correlated with sexual behaviour and sociosexuality (defined as an increased willingness to engage in sex without commitment) influences the perception of certain cues of physical attractiveness. Based on a sample of Slovak university students, we investigated relationships between 1) male and female mating success and reported body morphology (body mass index, BMI and waist-to-hip ratio, WHR) and 2) mate preference characteristics and mating success. Both males and females reported a similar number of long-term sexual partners and frequency of engaging in extra-pair copulation (EPC). The mating success of both sexes was positively mediated by self-perceived attractiveness. However, female BMI was inversely associated with mating success whereas increasing BMI was positively associated with male mating success (the total number of lifetime sexual partners) as well as with the likelihood of engaging in EPC. Unrestricted sociosexuality positively correlated with direct and indirect benefits from mating and negatively with the religious/political background of a potential mate and with the desire for a home/ children. These results confirm the hypothesis that human body morphology is associated with sexual behaviour and that cues of direct/indirect benefits in a potential mate positively correlate with sociosexuality.
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Harris, W Edwin; Uller, Tobias
2009-04-27
Reproductive investment decisions form an integral part of life-history biology. Selection frequently favours plasticity in investment that can generate maternal effects on offspring development. For example, if females differentially allocate resources based on mate attractiveness or quality, this can create a non-genetic link between mate attractiveness and offspring fitness with potential consequences for ecological and evolutionary dynamics. It is therefore important to understand under what conditions differential investment into offspring in relation to male quality is expected to occur and the direction of the effect. Two opposite predictions, increased investment into offspring produced with high-quality mates (differential allocation (DA)) and increased investment with low-quality males (reproductive compensation (RC)) have been suggested but no formal theoretical treatment justifying the assumptions underlying these two hypotheses has been conducted to date. Here, we used a state-based approach to investigate the circumstances under which the variation in mate quality results in differential female investment into offspring and how this interacts with female energetic resource levels. We found that a pattern of increased investment when mating with high-quality mates (i.e. DA) was the most common optimal investment strategy for females in our model. By contrast, increased investment when mating with low-quality mates (i.e. RC) was predicted only when the relative impact of parental investment on offspring quality was low. Finally, we found that the specific pattern of investment in relation to male quality depends on female energetic state, the likelihood for future mating opportunities and the expected future distribution of mate quality. Thus, the female's age and body condition should be important factors mediating DA and RC, which may help to explain the equivocal results of empirical studies.
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Kent, Clement; Azanchi, Reza; Smith, Ben; Chu, Adrienne; Levine, Joel
2007-01-01
Drosophila Cuticular Hydrocarbons (CH) influence courtship behaviour, mating, aggregation, oviposition, and resistance to desiccation. We measured levels of 24 different CH compounds of individual male D. melanogaster hourly under a variety of environmental (LD/DD) conditions. Using a model-based analysis of CH variation, we developed an improved normalization method for CH data, and show that CH compounds have reproducible cyclic within-day temporal patterns of expression which differ between LD and DD conditions. Multivariate clustering of expression patterns identified 5 clusters of co-expressed compounds with common chemical characteristics. Turnover rate estimates suggest CH production may be a significant metabolic cost. Male cuticular hydrocarbon expression is a dynamic trait influenced by light and time of day; since abundant hydrocarbons affect male sexual behavior, males may present different pheromonal profiles at different times and under different conditions. PMID:17896002
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da Silveira, Tayse Ferreira Ferreira; Meinhart, Adriana Dillenburg; de Souza, Thaís Cristina Lima; Cunha, Elenice Carla Emídio; de Moraes, Maria Rosa; Filho, José Teixeira; Godoy, Helena Teixeira
2017-06-01
The beverage obtained from the yerba mate tea, besides being the most consumed in Brazil, has high concentrations of chlorogenic acids. In this study, a central composite design was employed to establish the best infusion time, temperature and water volume to maximize the extraction of chlorogenic acids 5-caffeoylquinic (5CQ), 3.4-dicaffeoylquinic (3.4 DQ), 3.5-dicaffeoylquinic (3.5 DQ) and 4.5-dicaffeoylquinic (4.5 DQ), from the leaves and stems of yerba mate tea (beverage ready for consumption). Analyses were performed by high-performance liquid chromatography and the optimum conditions were obtained through the use of the desirability function of Derringer and Suich. The maximum chlorogenic acids content in the beverage was obtained when the infusion was prepared with 2 g of mate tea, in 300 mL of water at 95 °C, under infusion for 16 min. The optimal conditions were applied for the preparation of beverages from 15 commercial samples of yerba mate tea, and it was observed that the sum of the concentration of the four compounds showed variation of up to 79 times between the average of the samples, which can be attributed to climatic conditions of cultivation of the plant and/or of processing.
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Jones, Teri B; Drake, Anna; Green, David J
2014-05-07
In many bird species colour traits influence social dominance and breeding success. In our study we first evaluated whether the colour of the basic plumage (tail feathers grown at the end of the breeding season), that provides an index of individual quality, influenced winter habitat use by yellow warblers. We then evaluated whether winter habitat use (inferred using δ13C and δ15N signatures of winter grown greater-coverts) influenced alternate plumage colouration, after controlling for individual quality using basic plumage colouration. Finally, we investigated whether basic and alternate plumage colouration influenced arrival dates, mate acquisition, breeding phenology and reproductive success of yellow warblers breeding in southern (Revelstoke, B.C.) and arctic (Inuvik, N.W.T.) Canada. The colour (chroma and hue) of tail feathers, grown on the breeding grounds, was not related to subsequent winter habitat use. Greater covert and tail feather colour (chroma and hue) were correlated, suggesting genetics and/or individual quality played a role in pigment deposition. After controlling for individual difference in tail colour, δ13C values did not explain any variation in greater covert colour, but birds with high δ15N signatures had greater coverts with higher chroma. Male arrival dates varied with tail chroma in Revelstoke and tail hue in Inuvik. Males that arrived early paired with older and/or more colourful mates that initiated clutches earlier, and at one site (Revelstoke) were more likely to fledge young. In addition, in Revelstoke (but not Inuvik) males with high tail hue also acquired more colourful mates. In contrast, after controlling for individual differences in tail colour, greater covert colour did not affect male arrival date, the quality of the mate obtained or reproductive success in either population. Our results suggest that plumage colour effects on breeding phenology and mate acquisition result from differences in the intrinsic quality of individuals rather than a carry-over effect of winter habitat use.
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2014-01-01
Background In many bird species colour traits influence social dominance and breeding success. In our study we first evaluated whether the colour of the basic plumage (tail feathers grown at the end of the breeding season), that provides an index of individual quality, influenced winter habitat use by yellow warblers. We then evaluated whether winter habitat use (inferred using δ13C and δ15N signatures of winter grown greater-coverts) influenced alternate plumage colouration, after controlling for individual quality using basic plumage colouration. Finally, we investigated whether basic and alternate plumage colouration influenced arrival dates, mate acquisition, breeding phenology and reproductive success of yellow warblers breeding in southern (Revelstoke, B.C.) and arctic (Inuvik, N.W.T.) Canada. Results The colour (chroma and hue) of tail feathers, grown on the breeding grounds, was not related to subsequent winter habitat use. Greater covert and tail feather colour (chroma and hue) were correlated, suggesting genetics and/or individual quality played a role in pigment deposition. After controlling for individual difference in tail colour, δ13C values did not explain any variation in greater covert colour, but birds with high δ15N signatures had greater coverts with higher chroma. Male arrival dates varied with tail chroma in Revelstoke and tail hue in Inuvik. Males that arrived early paired with older and/or more colourful mates that initiated clutches earlier, and at one site (Revelstoke) were more likely to fledge young. In addition, in Revelstoke (but not Inuvik) males with high tail hue also acquired more colourful mates. In contrast, after controlling for individual differences in tail colour, greater covert colour did not affect male arrival date, the quality of the mate obtained or reproductive success in either population. Conclusions Our results suggest that plumage colour effects on breeding phenology and mate acquisition result from differences in the intrinsic quality of individuals rather than a carry-over effect of winter habitat use. PMID:24886073
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Mating behaviour of Pseudodiaptomus annandalei (Copepoda Calanoida) with emphasis on rejection rate
NASA Astrophysics Data System (ADS)
Dur, G.; Souissi, S.; Schmitt, F. G.; Hwang, J. S.; Cheng, S. H.
2009-04-01
Mating behaviour has important consequences at both individual and population levels. Reproductive fitness is of paramount importance to sustain the success of planktonic copepod populations in aquatic environments. The calanoid copepod Pseudodiaptomus annandalei has one of the largest geographical ranges for Indo-Pacific Pseudodiaptomidae. It is also of great importance in fish culture pounds south of Taiwan. However, the mating behavior of this species has never been studied. Mating and predatory behaviour are conceptually the same. In both cases, the encounter and the interactions occur between two individuals with opposite characteristics: predator-prey for predation; male-female for mating. The mating behaviour may be defined as a sequence of encounter, pursuit, capture and copulation. Several observed behaviour suggest that both sexes asses and choose among available mates before the copulation. Pre-copulatory mate choice in copepods may manifest as mate guarding where males attached to CV females until their final moult, complicated pre-copulatory dance and escaping. During our preliminary observations, we notice that P. annandalei females escape by shaking, often violently, the males that have caught them. Consequently for such a species the act of mating may be visualized as a chain of six events (i.e. search, encounter, pursuit, capture, selective dance, copulation).Within this chain, encounter, capture and copulation are conditional events depending on the successful conclusion of their preceding events in the chain. In this study, we examined the different step in the mating behaviour of the scarcely studied sub-tropical copepod, Pseudodiaptomus annandalei, collected from the Danshuei estuary (North Taiwan). The individuals were observed using a 3D optical system to obtain simultaneous front and side views. Males, when placed in the water where females had previously swum in, showed significant increase of their swimming velocities. Additionally, their swimming trajectories are more convoluted, indicating that males explore larger volume of fluid to increase the probability to encounter a female. The mate finding behaviour appears to depend not only on chemical signal but also on hydromechanical signals. Some males exhibited shifts of direction when females were passing by. When male intercepted a chemical trail left by a female, they initiate tracking behaviour racing up the trail with increasing speed. Males pursued pheromone trails up to 24 sec old and 10 mm long. Most studies of mating behaviour have focused on detection and sometimes pursuit, but few have addressed the other components of successful mating, namely, capture and copulation. Moreover, mate choice issue has largely been ignored in regards to pelagic copepods. Consequently very few are known about the plasticity of rejection rates as a function of mate encounter rates. The second aim of this experiment is to describe the process used by female to select their mate and to fill the gap in the quantification of mating success. Once caught by a male, P. annandalei's females entered in intensive dance which sometimes lead to shake off the males suggesting a female mate choice. The three-dimensional trajectories described by the couple during this event were characterized by fast loops and intense jumps. Individual's access to mates may be affected by operational sex ratios, causing strong variation in mating success. We finally manipulated adult sex ratios of the brackish copepod P. annandalei, to examine the influence of population sex ratio on mating success of P. annandalei in a final set of experiment concluding the investigation. It should be notice that, to our knowledge, it the first quantification ever done before. The plasticity of rejection rate was therefore investigated as a function of sex-ratio and mate encounter rate. The encounter rate reached maximum value for balanced proportion of male and female and decreased as the sex ratio unbalanced. Higher value of success was nevertheless observed for a pro-male sex-ratio.
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Imaging, Behavior and Endocrine Analysis of “Jealousy” in a Monogamous Primate
Maninger, Nicole; Mendoza, Sally P.; Williams, Donald R.; Mason, William A.; Cherry, Simon R.; Rowland, Douglas J.; Schaefer, Thomas; Bales, Karen L.
2018-01-01
Understanding the neurobiology of social bonding in non-human primates is a critical step in understanding the evolution of monogamy, as well as understanding the neural substrates for emotion and behavior. Coppery titi monkeys (Callicebus cupreus) form strong pair bonds, characterized by selective preference for their pair mate, mate-guarding, physiological and behavioral agitation upon separation, and social buffering. Mate-guarding, or the “maintenance” phase of pair bonding, is relatively under-studied in primates. In the current study, we used functional imaging to examine how male titi monkeys viewing their pair mate in close proximity to a stranger male would change regional cerebral glucose metabolism. We predicted that this situation would challenge the pair bond and induce “jealousy” in the males. Animals were injected with [18F]-fluorodeoxyglucose (FDG), returned to their cage for 30 min of conscious uptake, placed under anesthesia, and then scanned for 1 hour on a microPET P4 scanner. During the FDG uptake, males (n=8) had a view of either their female pair mate next to a stranger male (“jealousy” condition) or a stranger female next to a stranger male (control condition). Blood and cerebrospinal fluid samples were collected and assayed for testosterone, cortisol, oxytocin, and vasopressin. Positron emission tomography (PET) was co-registered with structural magnetic resonance imaging (MRI), and region of interest analysis was carried out. Bayesian multivariate multilevel analyses found that the right lateral septum (Pr(b>0)=93%), left posterior cingulate cortex (Pr(b>0)=99%), and left anterior cingulate (Pr(b>0)=96%) showed higher FDG uptake in the jealousy condition compared to the control condition, while the right medial amygdala (Pr(b>0)=85%) showed lower FDG uptake. Plasma testosterone and cortisol concentrations were higher during the jealousy condition. During the jealousy condition, duration of time spent looking across at the pair mate next to a stranger male was associated with higher plasma cortisol concentrations. The lateral septum has been shown to be involved in mate-guarding and mating-induced aggression in monogamous rodents, while the cingulate cortex has been linked to territoriality. These neural and physiological changes may underpin the emotion of jealousy, which can act in a monogamous species to preserve the long-term integrity of the pair. PMID:29682503
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Imaging, Behavior and Endocrine Analysis of "Jealousy" in a Monogamous Primate.
Maninger, Nicole; Mendoza, Sally P; Williams, Donald R; Mason, William A; Cherry, Simon R; Rowland, Douglas J; Schaefer, Thomas; Bales, Karen L
2017-10-01
Understanding the neurobiology of social bonding in non-human primates is a critical step in understanding the evolution of monogamy, as well as understanding the neural substrates for emotion and behavior. Coppery titi monkeys ( Callicebus cupreus ) form strong pair bonds, characterized by selective preference for their pair mate, mate-guarding, physiological and behavioral agitation upon separation, and social buffering. Mate-guarding, or the "maintenance" phase of pair bonding, is relatively under-studied in primates. In the current study, we used functional imaging to examine how male titi monkeys viewing their pair mate in close proximity to a stranger male would change regional cerebral glucose metabolism. We predicted that this situation would challenge the pair bond and induce "jealousy" in the males. Animals were injected with [ 18 F]-fluorodeoxyglucose (FDG), returned to their cage for 30 min of conscious uptake, placed under anesthesia, and then scanned for 1 hour on a microPET P4 scanner. During the FDG uptake, males (n=8) had a view of either their female pair mate next to a stranger male ("jealousy" condition) or a stranger female next to a stranger male (control condition). Blood and cerebrospinal fluid samples were collected and assayed for testosterone, cortisol, oxytocin, and vasopressin. Positron emission tomography (PET) was co-registered with structural magnetic resonance imaging (MRI), and region of interest analysis was carried out. Bayesian multivariate multilevel analyses found that the right lateral septum (Pr( b >0)=93%), left posterior cingulate cortex (Pr( b >0)=99%), and left anterior cingulate (Pr( b >0)=96%) showed higher FDG uptake in the jealousy condition compared to the control condition, while the right medial amygdala (Pr( b >0)=85%) showed lower FDG uptake. Plasma testosterone and cortisol concentrations were higher during the jealousy condition. During the jealousy condition, duration of time spent looking across at the pair mate next to a stranger male was associated with higher plasma cortisol concentrations. The lateral septum has been shown to be involved in mate-guarding and mating-induced aggression in monogamous rodents, while the cingulate cortex has been linked to territoriality. These neural and physiological changes may underpin the emotion of jealousy, which can act in a monogamous species to preserve the long-term integrity of the pair.
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Influence of Inbreeding on Female Mate Choice in Two Species of Drosophila
McKee, Amberle A.; Newton, Shanna M.
2016-01-01
Many organisms have been reported to choose their mates in order to increase the heterozygosity of their offspring by avoiding mating with relatives or homozygous individuals. Most previous studies using Drosophila melanogaster have used artificial chromosomes or extreme inbreeding treatments, situations unlikely to be matched in nature. Additionally, few studies have examined the interaction between female inbreeding status and her choice of mate. Using females and males from populations that had experienced either random mating or one generation of sib-sib inbreeding, we measured the preferences of females for males. Our results indicate that outbred males were chosen more often than inbred males and that this preference may be more pronounced in outbred females than in inbred ones. PMID:29225418
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Montoya, R Matthew
2008-10-01
Four studies investigated the importance of objective and subjective attributes to mate selection. This research tested whether perceivers' objective physical attractiveness influenced how they evaluated the physical attractiveness of others and, if considered, may provide a parsimonious account for matching in mate selection. Study 1 (N = 102) demonstrated that ratings of targets' attractiveness decreased as perceivers' objective physical attractiveness increased. Studies 2 (N = 89) and 3 (N = 68) revealed that as perceivers' objective physical attractiveness increased, reductions in expected satisfaction and rejection were mediated by perceivers' reduced assessments of targets' attractiveness. Study 4 (N = 114) produced patterns of matching by finding that attractive perceivers expected to date more attractive targets while unattractive perceivers expected to date less attractive targets. This research emphasizes the importance of objective physical attractiveness to target evaluations and describes how matching results from the combined influence of objective and subjective attributes.
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The chorus environment and the shape of communication systems in frogs
NASA Astrophysics Data System (ADS)
Marshall, Vince
2003-04-01
Many species of frogs breed in dense and structurally complex aggregations of calling males termed choruses. Females entering a chorus are faced with the tasks of recognizing and locating mates on the basis of their advertisement calls. The chorus environment poses particular challenges for communication as signalers and receivers will face high levels of background noise and interference between signals. For females, such conditions may decrease the efficiency of communication, with the consequences of increasing the time required to find a mate or errors in mate choice. For males, it will give rise to intense competition for the attention of females. Additionally, the chorus environment for a species is not static, and will vary over both spatial and temporal scales. This complex and dynamic environment has shaped the signals and signaling behaviors of frogs in sometimes surprising ways. In this talk, some of the implications of the chorus environment for both receivers and signalers is discussed. In particular, examples from North American hylid frogs are drawn upon and research on the role of signal timing in influencing the responses of females and plasticity in aggressive behavior between neighbors in choruses are discussed.
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Climate change alters reproductive isolation and potential gene flow in an annual plant.
Franks, Steven J; Weis, Arthur E
2009-11-01
Climate change will likely cause evolution due not only to selection but also to changes in reproductive isolation within and among populations. We examined the effects of a natural drought on the timing of flowering in two populations of Brassica rapa and the consequences for predicted reproductive isolation and potential gene flow. Seeds were collected before and after a 5-year drought in southern California from two populations varying in soil moisture. Lines derived from these seeds were raised in the greenhouse under wet and drought conditions. We found that the natural drought caused changes in reproductive timing and that the changes were greater for plants from the wet than from the dry site. This differential shift caused the populations to become more phenological similar, which should lead to less reproductive isolation and increased gene flow. We estimated a high level of assortative mating by flowering time, which potentially contributed to the rapid evolution of phenological traits following the drought. Estimates of assortative mating were higher for the wet site population, and assortative mating was reduced following the drought. This study shows that climate change can potentially alter gene flow and reproductive isolation within and among populations, strongly influencing evolution.
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Human body odour, symmetry and attractiveness.
Rikowski, A; Grammer, K
1999-01-01
Several studies have found body and facial symmetry as well as attractiveness to be human mate choice criteria. These characteristics are presumed to signal developmental stability. Human body odour has been shown to influence female mate choice depending on the immune system, but the question of whether smell could signal general mate quality, as do other cues, was not addressed in previous studies. We compared ratings of body odour, attractiveness, and measurements of facial and body asymmetry of 16 male and 19 female subjects. Subjects wore a T-shirt for three consecutive nights under controlled conditions. Opposite-sex raters judged the odour of the T-shirts and another group evaluated portraits of the subjects for attractiveness. We measured seven bilateral traits of the subject's body to assess body asymmetry. Facial asymmetry was examined by distance measurements of portrait photographs. The results showed a significant positive correlation between facial attractiveness and sexiness of body odour for female subjects. We found positive relationships between body odour and attractiveness and negative ones between smell and body asymmetry for males only if female odour raters were in the most fertile phase of their menstrual cycle. The outcomes are discussed in the light of different male and female reproductive strategies. PMID:10380676
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Gestural Communication and Mating Tactics in Wild Chimpanzees
Roberts, Anna Ilona; Roberts, Sam George Bradley
2015-01-01
The extent to which primates can flexibly adjust the production of gestural communication according to the presence and visual attention of the audience provides key insights into the social cognition underpinning gestural communication, such as an understanding of third party relationships. Gestures given in a mating context provide an ideal area for examining this flexibility, as frequently the interests of a male signaller, a female recipient and a rival male bystander conflict. Dominant chimpanzee males seek to monopolize matings, but subordinate males may use gestural communication flexibly to achieve matings despite their low rank. Here we show that the production of mating gestures in wild male East African chimpanzees (Pan troglodytes schweunfurthii) was influenced by a conflict of interest with females, which in turn was influenced by the presence and visual attention of rival males. When the conflict of interest was low (the rival male was present and looking away), chimpanzees used visual/ tactile gestures over auditory gestures. However, when the conflict of interest was high (the rival male was absent, or was present and looking at the signaller) chimpanzees used auditory gestures over visual/ tactile gestures. Further, the production of mating gestures was more common when the number of oestrous and non-oestrus females in the party increased, when the female was visually perceptive and when there was no wind. Females played an active role in mating behaviour, approaching for copulations more often when the number of oestrus females in the party increased and when the rival male was absent, or was present and looking away. Examining how social and ecological factors affect mating tactics in primates may thus contribute to understanding the previously unexplained reproductive success of subordinate male chimpanzees. PMID:26536467
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Hazlitt, S L; Sigg, D P; Eldridge, M D B; Goldizen, A W
2006-09-01
Ecological genetic studies have demonstrated that spatial patterns of mating dispersal, the dispersal of gametes through mating behaviour, can facilitate inbreeding avoidance and strongly influence the structure of populations, particularly in highly philopatric species. Elements of breeding group dynamics, such as strong structuring and sex-biased dispersal among groups, can also minimize inbreeding and positively influence levels of genetic diversity within populations. Rock-wallabies are highly philopatric mid-sized mammals whose strong dependence on rocky terrain has resulted in series of discreet, small colonies in the landscape. Populations show no signs of inbreeding and maintain high levels of genetic diversity despite strong patterns of limited gene flow within and among colonies. We used this species to investigate the importance of mating dispersal and breeding group structure to inbreeding avoidance within a 'small' population. We examined the spatial patterns of mating dispersal, the extent of kinship within breeding groups, and the degree of relatedness among brush-tailed rock-wallaby breeding pairs within a colony in southeast Queensland. Parentage data revealed remarkably restricted mating dispersal and strong breeding group structuring for a mid-sized mammal. Breeding groups showed significant levels of female kinship with evidence of male dispersal among groups. We found no evidence for inbreeding avoidance through mate choice; however, anecdotal data suggest the importance of life history traits to inbreeding avoidance between first-degree relatives. We suggest that the restricted pattern of mating dispersal and strong breeding group structuring facilitates inbreeding avoidance within colonies. These results provide insight into the population structure and maintenance of genetic diversity within colonies of the threatened brush-tailed rock-wallaby.
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Assortative mating can impede or facilitate fixation of underdominant alleles.
Newberry, Mitchell G; McCandlish, David M; Plotkin, Joshua B
2016-12-01
Underdominant mutations have fixed between divergent species, yet classical models suggest that rare underdominant alleles are purged quickly except in small or subdivided populations. We predict that underdominant alleles that also influence mate choice, such as those affecting coloration patterns visible to mates and predators alike, can fix more readily. We analyze a mechanistic model of positive assortative mating in which individuals have n chances to sample compatible mates. This one-parameter model naturally spans random mating (n=1) and complete assortment (n→∞), yet it produces sexual selection whose strength depends non-monotonically on n. This sexual selection interacts with viability selection to either inhibit or facilitate fixation. As mating opportunities increase, underdominant alleles fix as frequently as neutral mutations, even though sexual selection and underdominance independently each suppress rare alleles. This mechanism allows underdominant alleles to fix in large populations and illustrates how life history can affect evolutionary change. Copyright © 2016 Elsevier Inc. All rights reserved.
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Evans, Jonathan P; Simmons, Leigh W
2008-09-01
The good-sperm and sexy-sperm (GS-SS) hypotheses predict that female multiple mating (polyandry) can fuel sexual selection for heritable male traits that promote success in sperm competition. A major prediction generated by these models, therefore, is that polyandry will benefit females indirectly via their sons' enhanced fertilization success. Furthermore, like classic 'good genes' and 'sexy son' models for the evolution of female preferences, GS-SS processes predict a genetic correlation between genes for female mating frequency (analogous to the female preference) and those for traits influencing fertilization success (the sexually selected traits). We examine the premise for these predictions by exploring the genetic basis of traits thought to influence fertilization success and female mating frequency. We also highlight recent debates that stress the possible genetic constraints to evolution of traits influencing fertilization success via GS-SS processes, including sex-linked inheritance, nonadditive effects, interacting parental genotypes, and trade-offs between integrated ejaculate components. Despite these possible constraints, the available data suggest that male traits involved in sperm competition typically exhibit substantial additive genetic variance and rapid evolutionary responses to selection. Nevertheless, the limited data on the genetic variation in female mating frequency implicate strong genetic maternal effects, including X-linkage, which is inconsistent with GS-SS processes. Although the relative paucity of studies on the genetic basis of polyandry does not allow us to draw firm conclusions about the evolutionary origins of this trait, the emerging pattern of sex linkage in genes for polyandry is more consistent with an evolutionary history of antagonistic selection over mating frequency. We advocate further development of GS-SS theory to take account of the complex evolutionary dynamics imposed by sexual conflict over mating frequency.
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Maner, Jon K.
2016-01-01
The color red has special meaning in mating-relevant contexts. Wearing red can enhance perceptions of women’s attractiveness and desirability as a potential romantic partner. Building on recent findings, the present study examined whether women’s (N = 74) choice to display the color red is influenced by the attractiveness of an expected opposite-sex interaction partner. Results indicated that female participants who expected to interact with an attractive man displayed red (on clothing, accessories, and/or makeup) more often than a baseline consisting of women in a natural environment with no induced expectation. In contrast, when women expected to interact with an unattractive man, they eschewed red, displaying it less often than in the baseline condition. Findings are discussed with respect to evolutionary and cultural perspectives on mate evaluation and selection. PMID:26960135
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Uchitomi, Hirotaka; Ogawa, Ken-ichiro; Orimo, Satoshi; Wada, Yoshiaki; Miyake, Yoshihiro
2016-01-01
Although human walking gait rhythms are generated by native individual gait dynamics, these gait dynamics change during interactions between humans. A typical phenomenon is synchronization of gait rhythms during cooperative walking. Our previous research revealed that fluctuation characteristics in stride interval of subjects with Parkinson’s disease changed from random to 1/f fluctuation as fractal characteristics during cooperative walking with the gait assist system Walk-Mate, which emulates a human interaction using interactive rhythmic cues. Moreover, gait dynamics were relearned through Walk-Mate gait training. However, the system’s clinical efficacy was unclear because the previous studies did not focus on specific gait rhythm disorder symptoms. Therefore, this study aimed to evaluate the effect of Walk-Mate on festinating gait among subjects with Parkinson’s disease. Three within-subject experimental conditions were used: (1) preinteraction condition, (2) interaction condition, and (3) postinteraction condition. The only difference between conditions was the interactive rhythmic cues generated by Walk-Mate. Because subjects with festinating gait gradually and involuntarily decreased their stride interval, the regression slope of stride interval as an index of severity of preinteraction festinating gait was elevated. The regression slope in the interaction condition was more gradual than during the preinteraction condition, indicating that the interactive rhythmic cues contributed to relieving festinating gait and stabilizing gait dynamics. Moreover, the gradual regression slope was carried over to the postinteraction condition, indicating that subjects with festinating gait have the potential to relearn stable gait dynamics. These results suggest that disordered gait dynamics are clinically restored through interactive rhythmic cues and that Walk-Mate may have the potential to assist therapists in more effective rehabilitation. Trial Registration: UMIN Clinical Trials Registry UMIN000012591 PMID:27253376
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Uchitomi, Hirotaka; Ogawa, Ken-Ichiro; Orimo, Satoshi; Wada, Yoshiaki; Miyake, Yoshihiro
2016-01-01
Although human walking gait rhythms are generated by native individual gait dynamics, these gait dynamics change during interactions between humans. A typical phenomenon is synchronization of gait rhythms during cooperative walking. Our previous research revealed that fluctuation characteristics in stride interval of subjects with Parkinson's disease changed from random to 1/f fluctuation as fractal characteristics during cooperative walking with the gait assist system Walk-Mate, which emulates a human interaction using interactive rhythmic cues. Moreover, gait dynamics were relearned through Walk-Mate gait training. However, the system's clinical efficacy was unclear because the previous studies did not focus on specific gait rhythm disorder symptoms. Therefore, this study aimed to evaluate the effect of Walk-Mate on festinating gait among subjects with Parkinson's disease. Three within-subject experimental conditions were used: (1) preinteraction condition, (2) interaction condition, and (3) postinteraction condition. The only difference between conditions was the interactive rhythmic cues generated by Walk-Mate. Because subjects with festinating gait gradually and involuntarily decreased their stride interval, the regression slope of stride interval as an index of severity of preinteraction festinating gait was elevated. The regression slope in the interaction condition was more gradual than during the preinteraction condition, indicating that the interactive rhythmic cues contributed to relieving festinating gait and stabilizing gait dynamics. Moreover, the gradual regression slope was carried over to the postinteraction condition, indicating that subjects with festinating gait have the potential to relearn stable gait dynamics. These results suggest that disordered gait dynamics are clinically restored through interactive rhythmic cues and that Walk-Mate may have the potential to assist therapists in more effective rehabilitation. UMIN Clinical Trials Registry UMIN000012591.
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Demography, environmental uncertainty, and the evolution of mate desertion in the snail kite
Beissinger, S.R.
1986-01-01
The Snail Kite (Rostrhamus sociabilis), an endangered hawk, has a unique mating system in Florida (Beissinger and Snyder 1987): when food is abundant, males or females desert their mates at nearly equal frequency (ambisexual mate desertion) in the midst of a nesting cycle. I examined the demographic and environmental constraints selecting for a clutch size that permits one parent to desert, yet optimizes the number of offspring produced by each parent. Demographic studies, conducted from 1979-1983, indicated that kites have (1) a very high nest failure rate (?= 68%) due most often to unstable nest sites and predation, (2) a variable nesting season (5-10 mo/yr), (3) an early age of first reproduction for a bird this size (10 mo), (4) a high degree of iteroparity (double and potentially triple clutching within a season), and (5) unstable populations. Both nesting success and population size were directly related to Everglades water levels and resultant snail densities. Kites responded to large annual changes in food abundance, not by adjusting clutch size but by deserting their mates and presumably attempting to renest. Kite demographic traits appear to be adaptations to or results of an uncertain environment. Based on 67 yr of Everglades water levels, environmental predictability, measured by spectral analysis and Colwell's (1974) index, was low and influenced by water management regimes: (1) water levels were lowered, (2) annual variation in levels increased and annual cycles became stronger, (3) the period length of long-term drought-flood cycles shifted from 10 or more yr toward 5 yr, and (4) levels became a less predictive cue for favorable nesting conditions. A potential evolutionary pathway from biparental care to mate desertion in Snail Kites is proposed. It is unlikely that mate desertion evolved solely from a context of conflict between the sexes, because kite nesting success is so low that it is probably maladaptive for a parent to desert and jeopardize the survival of any of its first brood. Instead, mate desertion behavior probably evolved in response to a smaller average clutch size; this would allow females to be highly iteroparous and avoid the costs of overinvestment, and should be strongly favored in a highly uncertain environment. Analysis of clutches in museum collections suggests that an apparent decline in clutch size may have occurred in Florida during the past century. The potential for ambisexual mate desertion to occur in other vertebrates is during the past century. The potential for ambisexual mate desertion to occur in other vertebrates is examined.
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Non-random mate choice in humans: insights from a genome scan.
Laurent, R; Toupance, B; Chaix, R
2012-02-01
Little is known about the genetic factors influencing mate choice in humans. Still, there is evidence for non-random mate choice with respect to physical traits. In addition, some studies suggest that the Major Histocompatibility Complex may affect pair formation. Nowadays, the availability of high density genomic data sets gives the opportunity to scan the genome for signatures of non-random mate choice without prior assumptions on which genes may be involved, while taking into account socio-demographic factors. Here, we performed a genome scan to detect extreme patterns of similarity or dissimilarity among spouses throughout the genome in three populations of African, European American, and Mexican origins from the HapMap 3 database. Our analyses identified genes and biological functions that may affect pair formation in humans, including genes involved in skin appearance, morphogenesis, immunity and behaviour. We found little overlap between the three populations, suggesting that the biological functions potentially influencing mate choice are population specific, in other words are culturally driven. Moreover, whenever the same functional category of genes showed a significant signal in two populations, different genes were actually involved, which suggests the possibility of evolutionary convergences. © 2011 Blackwell Publishing Ltd.
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Reappraising factors affecting mourning dove perch coos
Sayre, M.W.; Atkinson, R.D.; Baskett, T.S.; Haas, G.H.
1978-01-01
Results confirmed pairing as the primary factor influencing perch-cooing rates of wild mourning doves (Zenaida macroura). Marked unmated males cooed at substantially higher rates (6.2x) than mated males, had greater probability of cooing (2.3x) during 3-minute periods, and continued cooing longer each morning than mated males. Population density was not a major factor affecting cooing. Unmated males cooed more frequently in the presence of other cooing doves (P < 0.05) than when alone, but the number of additional doves above 1 was unimportant. Cooing rates of both mated and unmated males on areas with dissimilar dove densities were not significantly different. Within limits of standard call-count procedure, weather exerted no detectable influence on cooing.
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Dynamics of cell wall elasticity pattern shapes the cell during yeast mating morphogenesis
Goldenbogen, Björn; Giese, Wolfgang; Hemmen, Marie; Uhlendorf, Jannis; Herrmann, Andreas
2016-01-01
The cell wall defines cell shape and maintains integrity of fungi and plants. When exposed to mating pheromone, Saccharomyces cerevisiae grows a mating projection and alters in morphology from spherical to shmoo form. Although structural and compositional alterations of the cell wall accompany shape transitions, their impact on cell wall elasticity is unknown. In a combined theoretical and experimental approach using finite-element modelling and atomic force microscopy (AFM), we investigated the influence of spatially and temporally varying material properties on mating morphogenesis. Time-resolved elasticity maps of shmooing yeast acquired with AFM in vivo revealed distinct patterns, with soft material at the emerging mating projection and stiff material at the tip. The observed cell wall softening in the protrusion region is necessary for the formation of the characteristic shmoo shape, and results in wider and longer mating projections. The approach is generally applicable to tip-growing fungi and plants cells. PMID:27605377
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Quality of public information matters in mate-choice copying in female zebra finches.
Kniel, Nina; Schmitz, Jennifer; Witte, Klaudia
2015-01-01
Mate-choice copying is a form of social learning in which an individual gains information about potential mates by observing conspecifics. However, it is still unknown what kind of information drives the decision of an individual to copy the mate choice of others. Among zebra finches (Taeniopygia guttata castanotis), only females (not males) copy the mate choice of others. We tested female zebra finches in a binary choice test where they, first, could choose between two males of different phenotypes: one unadorned male and one male artificially adorned with a red feather on the forehead. After this mate-choice test, females could observe a single unadorned male and a pair of zebra finches, i.e. a wild-type female and her adorned mate. Pair interactions were either restricted to acoustic and visual communication (clear glass screen between pair mates) or acoustic communication alone (opaque screen between pair mates). After the observation period, females could again choose between new males of the two phenotypes in a second mate-choice test. In experiments with a clear glass screen, time spent with the respective males changed between the two mate-choice tests, and females preferred adorned over unadorned males during the second mate-choice test. In experiments with an opaque screen, time spent with the respective males did not change between the two mate-choice tests, although females lost an initial preference for unadorned males. Our results demonstrate that the quality of the received public information (visual and acoustic interaction of the observed pair) influences mate-choice copying in female zebra finches.
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Divorce and infidelity are associated with skewed adult sex ratios in birds.
Liker, András; Freckleton, Robert P; Székely, Tamás
2014-04-14
Adult sex ratio (ASR) is a fundamental concept in population demography, and recent theory suggests that ASR plays a central role in social behavior, mating systems, and parental care. Unbalanced ASRs are predicted to influence pair-bond and mating behavior, since the rarer sex in the population has more potential partners to mate with than the more common sex. Here we use phylogenetic comparative analyses to test whether ASR is related to three major aspects of mating behavior: divorce, social polygamy, and pair-bond infidelity. ASR is strongly correlated with long-term pair bonds, since the divorce rate is higher in species with a female-biased sex ratio, indicating that mate change by pair members and/or breaking of pair bonds by unmated individuals is more frequent when females outnumber males. Short-term pair bonds are also associated with unbalanced ASRs: males are more commonly polygamous when females outnumber males, and conversely, females are more polygamous when males outnumber females. Furthermore, infidelity increases with male-biased ASR in socially monogamous birds, suggesting that male coercion and/or female willingness to cheat the partner are facilitated by male-biased ASR. Our results provide the first comprehensive support for the proposition that ASR influences multiple aspects of pair-bond and mating behavior in wild populations. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Adult sex ratio variation: implications for breeding system evolution.
Székely, T; Weissing, F J; Komdeur, J
2014-08-01
Adult sex ratio (ASR) exhibits immense variation in nature, although neither the causes nor the implications of this variation are fully understood. According to theory, the ASR is expected to influence sex roles and breeding systems, as the rarer sex in the population has more potential partners to mate with than the more common sex. Changes in mate choice, mating systems and parental care suggest that the ASR does influence breeding behaviour, although there is a need for more tests, especially experimental ones. In the context of breeding system evolution, the focus is currently on operational sex ratios (OSRs). We argue that the ASR plays a role of similar importance and urge researchers to study the ASR and the OSR side by side. Finally, we plead for a dynamic view of breeding system evolution with feedbacks between mating, parenting, OSR and ASR on both ecological and evolutionary time scales. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.
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Huchard, Elise; Canale, Cindy I; Le Gros, Chloé; Perret, Martine; Henry, Pierre-Yves; Kappeler, Peter M
2012-04-07
Classic sex roles depict females as choosy, but polyandry is widespread. Empirical attempts to understand the evolution of polyandry have often focused on its adaptive value to females, whereas 'convenience polyandry' might simply decrease the costs of sexual harassment. We tested whether constraint-free female strategies favour promiscuity over mating selectivity through an original experimental design. We investigated variation in mating behaviour in response to a reversible alteration of sexual dimorphism in body mass in the grey mouse lemur, a small primate where female brief sexual receptivity allows quantifying polyandry. We manipulated body condition in captive females, predicting that convenience polyandry would increase when females are weaker than males, thus less likely to resist their solicitations. Our results rather support the alternative hypothesis of 'adaptive polyandry': females in better condition are more polyandrous. Furthermore, we reveal that multiple mating incurs significant energetic costs, which are strikingly symmetrical between the sexes. Our study shows that mouse lemur females exert tight control over mating and actively seek multiple mates. The benefits of remating are nevertheless not offset by its costs in low-condition females, suggesting that polyandry is a flexible strategy yielding moderate fitness benefits in this small mammal.
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Huchard, Elise; Canale, Cindy I.; Le Gros, Chloé; Perret, Martine; Henry, Pierre-Yves; Kappeler, Peter M.
2012-01-01
Classic sex roles depict females as choosy, but polyandry is widespread. Empirical attempts to understand the evolution of polyandry have often focused on its adaptive value to females, whereas ‘convenience polyandry’ might simply decrease the costs of sexual harassment. We tested whether constraint-free female strategies favour promiscuity over mating selectivity through an original experimental design. We investigated variation in mating behaviour in response to a reversible alteration of sexual dimorphism in body mass in the grey mouse lemur, a small primate where female brief sexual receptivity allows quantifying polyandry. We manipulated body condition in captive females, predicting that convenience polyandry would increase when females are weaker than males, thus less likely to resist their solicitations. Our results rather support the alternative hypothesis of ‘adaptive polyandry’: females in better condition are more polyandrous. Furthermore, we reveal that multiple mating incurs significant energetic costs, which are strikingly symmetrical between the sexes. Our study shows that mouse lemur females exert tight control over mating and actively seek multiple mates. The benefits of remating are nevertheless not offset by its costs in low-condition females, suggesting that polyandry is a flexible strategy yielding moderate fitness benefits in this small mammal. PMID:21976684
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Size and competitive mating success in the yeast Saccharomyces cerevisiae.
Smith, Carl; Pomiankowski, Andrew; Greig, Duncan
2014-03-01
In unicellular organisms like yeast, mating with the right partner is critical to future fitness because each individual can only mate once. Because cell size is important for viability, mating with a partner of the right size could be a significant advantage. To investigate this idea, we manipulated the size of unmated yeast cells and showed that their viability depended on environmental conditions; large cells do better on rich medium and small cells do better on poor medium. We also found that the fitness of offspring is determined by the size of their parents. Finally, we demonstrated that when a focal cell of one mating type was placed with a large and a small cell of the opposite mating type, it was more likely to mate with the cell that was closer to the optimum size for growth in a given environment. This pattern was not generated by differences in passive mating efficiency of large and small cells across environments but by competitive mating behavior, mate preference, or both. We conclude that the most likely mechanism underlying this interesting behavior is that yeast cells compete for mates by producing pheromone signals advertising their viability, and cells with the opportunity to choose prefer to mate with stronger signalers because such matings produce more viable offspring.
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Matos, Yvonne K; Osborne, Jason A; Schal, Coby
2017-11-07
Bed bugs (Cimex lectularius L.) are now endemic in most major cities, but information regarding their basic biology is still largely based on research done over four decades ago. We investigated the effects of starvation, mating, sperm storage, and female and male age on egg production and hatch. Egg production cycles varied with the number of bloodmeals that females received. Once-mated females fed every 5 d had constant egg production for ∼75 d followed by a monotonic decline to near zero. Percentage egg hatch was high and constant, but declined after ∼30 d to near zero. To determine whether the age of the female, male, or sperm affected these patterns, we mated newly eclosed females to 60-d-old virgin males, 60-d-old mated males, or newly eclosed males. Females produced the most eggs when mated to young males, followed by old mated males, and then old virgin males; percentage hatch followed a similar pattern, suggesting that sperm stored within males for long was deficient. To examine effects of sperm stored within females, we mated newly eclosed females, starved them for 30 or 60 d, then fed them every 5 d. The 60-d starved group produced fewer eggs than the 30-d starved group, and both produced fewer eggs than young females mated to old or young males. Longer periods of sperm storage within females caused lower corresponding percentage hatch. These findings indicate egg production and hatch are governed by complex interactions among female and male age, frequency of feeding and mating, and sperm condition. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Xavier, L M S; Magalhães, D M; Viana, P A; Blassioli-Moraes, M C; Borges, M; Barrigossi, J A F; Vilela, E F; Laumann, R A
2018-04-01
The objective of this work was to evaluate the reproductive behavior and response of Elasmopalpus lignosellus (Zeller) males to calling females. Frequency of mating was recorded in couples during the first 7 days of the adult stage. Calling behavior of females was observed during the first 4 days of the adult stage and responses of males, in the same age intervals, to calling females were recorded in wind tunnel bioassays. The maximum number of matings occurred when the couple was between 24 and 48 h old. The scotophase period significantly influenced mating behavior, which peaked between 6 and 8 h of darkness and the mean mating duration was 93.9 ± 4.2 min. Calling females, when evaluated in a wind tunnel, attracted significantly more males than in bioassays with clean air (control). The number of individuals in calling behavior was significantly lower for females that were between 0 to 24 h old compared to the other females evaluated, but this did not influence male response. A lower proportion of males between 48 to 72 h old responded to calling females and these responses were delayed in comparison with males of other ages (0 to 24, 24 to 48, and 72 to 96 h old). These results indicate that the age of E. lignosellus males influences the response to conspecific calling females.
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Effect of elevated carbon dioxide on shoal familiarity and metabolism in a coral reef fish
Nadler, Lauren E.; Killen, Shaun S.; McCormick, Mark I.; Watson, Sue-Ann; Munday, Philip L.
2016-01-01
Atmospheric CO2 is expected to more than double by the end of the century. The resulting changes in ocean chemistry will affect the behaviour, sensory systems and physiology of a range of fish species. Although a number of past studies have examined effects of CO2 in gregarious fishes, most have assessed individuals in social isolation, which can alter individual behaviour and metabolism in social species. Within social groups, a learned familiarity can develop following a prolonged period of interaction between individuals, with fishes preferentially associating with familiar conspecifics because of benefits such as improved social learning and greater foraging opportunities. However, social recognition occurs through detection of shoal-mate cues; hence, it may be disrupted by near-future CO2 conditions. In the present study, we examined the influence of elevated CO2 on shoal familiarity and the metabolic benefits of group living in the gregarious damselfish species the blue-green puller (Chromis viridis). Shoals were acclimated to one of three nominal CO2 treatments: control (450 µatm), mid-CO2 (750 µatm) or high-CO2 (1000 µatm). After a 4–7 day acclimation period, familiarity was examined using a choice test, in which individuals were given the choice to associate with familiar shoal-mates or unfamiliar conspecifics. In control conditions, individuals preferentially associated with familiar shoal-mates. However, this association was lost in both elevated-CO2 treatments. Elevated CO2 did not impact the calming effect of shoaling on metabolism, as measured using an intermittent-flow respirometry methodology for social species following a 17–20 day acclimation period to CO2 treatment. In all CO2 treatments, individuals exhibited a significantly lower metabolic rate when measured in a shoal vs. alone, highlighting the complexity of shoal dynamics and the processes that influence the benefits of shoaling. PMID:27933164
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Noer, Christina Lehmkuhl; Balsby, Thorsten Johannes Skovbjerg; Anistoroaei, Razvan; Stelvig, Mikkel; Dabelsteen, Torben
2017-12-01
Mate choice studies suggest that choosy females benefit from increased fecundity, litter size, and offspring survival. Thus, providing females with the opportunity to choose among potential mates, deemed genetically suitable based on studbook data, might improve breeding management in production and zoo animals and thereby the sustainability of captive populations. Investigating mate preference via odor from potential mates before animal transfer is a proposed strategy for incorporating mate choice into breeding management. In this study, we test whether olfactory cues and signals from males can be used to assess and measure female mate preference in American mink. Eighteen females were subjected to a 4-day stimulus test in which females showed a preference for one of two males' urine and feces. Subsequently, each female was subjected to a 10-day mate preference test involving the same two males of the first test. Paternity tests revealed that 13 females had offspring, which could be assigned to only one male, suggesting that these females performed a mate choice. In nine of these females preference during the stimulus test was directed toward the male that fathered their offspring. Our results suggest that even though there was a preference difference in scent stimulus trials from potential mates this preference was not predictive of eventual mate preference or paternity. Other factors such as aspects of male behavior seem to play a role, when the mates are introduced. Our study supports that mate preference and mate choice are complex matters influenced by multiple cues and signals. © 2017 Wiley Periodicals, Inc.
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Using time-dependent models to investigate body condition and growth rate of the giant gartersnake
Coates, P.S.; Wylie, G.D.; Halstead, B.J.; Casazza, Michael L.
2009-01-01
Identifying links between phenotypic attributes and fitness is a primary goal of reproductive ecology. Differences in within-year patterns of body condition between sexes of gartersnakes in relation to reproduction and growth are not fully understood. We conducted an 11-year field study of body condition and growth rate of the giant gartersnake Thamnophis gigas across 13 study areas in the Central Valley of California, USA. We developed a priori mixed effects models of body condition index (BCI), which included covariates of time, sex and snout-vent length and reported the best-approximating models using an information theoretic approach. Also, we developed models of growth rate index (GRI) using covariates of sex and periods based on reproductive behavior. The largest difference in BCI between sexes, as predicted by a non-linear (cubic) time model, occurred during the mating period when female body condition (0.014??0.001 se) was substantially greater than males (-0.027??0.002 se). Males likely allocated energy to search for mates, while females likely stored energy for embryonic development. We also provided evidence that males use more body energy reserves than females during hibernation, perhaps because of different body temperatures between sexes. We found GRI of male snakes was substantially lower during the mating period than during a non-mating period, which indicated that a trade-off existed between searching for mates and growth. These findings contribute to our understanding of snake ecology in a Mediterranean climate. ?? 2009 The Zoological Society of London.
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Fitzpatrick, Courtney L; Altmann, Jeanne; Alberts, Susan C
2015-06-01
The paradigm of competitive males vying to influence female mate choice has been repeatedly upheld, but, increasingly, studies also report competitive females and choosy males. One female trait that is commonly proposed to influence male mate choice is the exaggerated sexual swelling displayed by females of many Old World primate species. The reliable indicator hypothesis posits that females use the exaggerated swellings to compete for access to mates, and that the swellings advertise variation in female fitness. We tested the two main predictions of this hypothesis in a wild population of baboons ( Papio cynocephalus) . First, we examined the effect of swelling size on the probability of mate-guarding ('consortship') by the highest-ranking male and the behavior of those males that trailed consorshipts ('follower males'). Second, we asked whether a female's swelling size predicted several fitness measures. We found that high-ranking males do not prefer females with larger swellings (when controlling for cycle number and conception) and that females with larger swellings did not have higher reproductive success. Our study-the only complete test of the reliable indicator hypothesis in a primate population-rejects the idea that female baboons compete for mates by advertising heritable fitness differences. Furthermore, we found unambiguous evidence that males biased their mating decisions in favor of females who had experienced more sexual cycles since their most recent pregnancy. Thus, rather than tracking the potential differences in fitness between females, male baboons appear to track and target the potential for a given reproductive opportunity to result in fertilization.
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Fitzpatrick, Courtney L.; Altmann, Jeanne; Alberts, Susan C.
2015-01-01
The paradigm of competitive males vying to influence female mate choice has been repeatedly upheld, but, increasingly, studies also report competitive females and choosy males. One female trait that is commonly proposed to influence male mate choice is the exaggerated sexual swelling displayed by females of many Old World primate species. The reliable indicator hypothesis posits that females use the exaggerated swellings to compete for access to mates, and that the swellings advertise variation in female fitness. We tested the two main predictions of this hypothesis in a wild population of baboons (Papio cynocephalus). First, we examined the effect of swelling size on the probability of mate-guarding (‘consortship’) by the highest-ranking male and the behavior of those males that trailed consorshipts (‘follower males’). Second, we asked whether a female’s swelling size predicted several fitness measures. We found that high-ranking males do not prefer females with larger swellings (when controlling for cycle number and conception) and that females with larger swellings did not have higher reproductive success. Our study—the only complete test of the reliable indicator hypothesis in a primate population—rejects the idea that female baboons compete for mates by advertising heritable fitness differences. Furthermore, we found unambiguous evidence that males biased their mating decisions in favor of females who had experienced more sexual cycles since their most recent pregnancy. Thus, rather than tracking the potential differences in fitness between females, male baboons appear to track and target the potential for a given reproductive opportunity to result in fertilization. PMID:26752790
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Gregory, K E; Maurer, R R
1991-03-01
Brown Swiss-Hereford (BS-H) reciprocal cross embryos were transferred to BS and H recipient cows and Red Poll-Angus (RP-A) reciprocal cross embryos were transferred to RP and A recipient cows to estimate the relative contributions of ovum cytoplasm and uterine influences to prenatal maternal effects. Calves resulting from embryo transfers (ET) were weaned early (3 to 5 d). Reciprocal cross mating also were made by natural service (NS) between BS and H and between RP and A breeds; part of the offspring were weaned at 3 to 5 d, and the remainder nursed their dams to an age of 150 to 180 d. This was done to estimate breed differences in prenatal and postnatal effects combined and to separate the effects of prenatal maternal influences from postnatal maternal influences of these breeds. Females produced in both ET and NS parts of the experiment were retained to produce three calf crops to an age of about 4.5 yr. The following traits were analyzed: percentage of conception rate; percentage of calf survival; percentage of calves produced per cow exposed; birth and weaning weights of calves produced; and periodic weights, heights, and condition scores of females to an age of 4.5 yr. Neither breed of donor (cytoplasmic influence) nor breed of recipient (uterine influence) had consistently important effects on the traits evaluated. In NS matings, differences between reciprocal crosses were small for most of the traits evaluated. Method of rearing (nursed vs weaned at 3 to 5 d) had no effect on reproductive and maternal traits for RP-A reciprocal cross females, but females that nursed generally were heavier, were taller, and had higher condition scores at most ages than early-weaned females. For the BS-H reciprocal cross, early-weaned females were favored over females reared by their dams in percentage of calves produced per cow exposed, but the method of rearing did not affect other reproductive or maternal traits. BS-H reciprocal cross females that nursed their dams were heavier at 550 d and were heavier and had higher condition scores at an age of 34 mo than early-weaned females.
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Kim, Jung-Mi; Hong, Sung Kee; Kim, Wan Gyu; Chun, Se-Chul; Yu, Seung-Hun
2009-01-01
Twenty-five isolates of Fusarium fujikuroi acquired from rice seeds and rice plants evidencing symptoms of Bakanae disease were evaluated to determine their mating types and characterize the formation of their sexual state. The mating types of the isolates were evaluated via multiplex PCR with the diagnostic primers of the mating-type (MAT) region: GFmat1a, GFmat1b, GFmat2c, and GFmat2d. Among the 25 isolates, 11 were identified as MAT-1 (male), and 14 as MAT-2 (female). Four MAT-1 isolates and three MAT-2 isolates were mated and cultured to evaluate the optimal culture conditions for the production of their sexual states. Among four tested media, 10% V8 juice agar proved optimal for the perithecial production of the isolates. The isolates also generated the largest numbers of perithecia when incubated at 23℃ in alternating cycles of 12 hr fluorescent light and NUV fluorescent light and 12 hr darkness. PMID:23983543
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Optimal level of inbreeding in the common lizard
Richard, M.; Losdat, S.; Lecomte, J.; de Fraipont, M.; Clobert, J.
2009-01-01
Mate choice with regard to genetic similarity has been rarely considered as a dynamic process. We examined this possibility in breeding populations of the common lizard (Lacerta vivipara) kept for several years in semi-natural conditions. We investigated whether they displayed a pattern of mate choice according to the genetic similarity and whether it was context-dependent. Mate choice depended on genetic similarity with the partner and also on age and condition. There was no systematic avoidance of inbreeding. Females of intermediate ages, more monogamous, did not mate with genetically similar partners, whereas younger and older females, more polyandrous, did but highest clutch proportions were associated with intermediate values of pair-relatedness. These results indicate dynamic mate choice, suggesting that individuals of different phenotypes select their partners in different ways according to their genetic similarity. We consider our results in the light of diverse and apparently contradictory theories concerning genetic compatibility, and particularly, optimal inbreeding and inclusive fitness. PMID:19419985
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Mating patterns have direct application to: conservation because of their influence on structuring genetic diversity within and among populations and on maintaining that diversity over time. We measured population and family outcrossing rates, biparental inbreeding correlation of...
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Yue, Gen Hua; Xia, Jun Hong; Liu, Feng; Lin, Grace
2012-01-01
Movement of individuals influences individual reproductive success, fitness, genetic diversity and relationships among individuals within populations and gene exchange among populations. Competition between males or females for mating opportunities and/or local resources predicts a female bias in taxa with monogamous mating systems and a male-biased dispersal in polygynous species. In birds and mammals, the patterns of dispersal between sexes are well explored, while dispersal patterns in protandrous hermaphroditic fish species have not been studied. We collected 549 adult individuals of Asian seabass (Lates calcarifer) from four locations in the South China Sea. To assess the difference in patterns of dispersal between sexes, we genotyped all individuals with 18 microsatellites. Significant genetic differentiation was detected among and within sampling locations. The parameters of population structure (F ST), relatedness (r) and the mean assignment index (mAIC), in combination with data on tagging-recapture, supplied strong evidences for female-biased dispersal in the Asian seabass. This result contradicts our initial hypothesis of no sex difference in dispersal. We suggest that inbreeding avoidance of females, female mate choice under the condition of low mate competition among males, and male resource competition create a female-biased dispersal. The bigger body size of females may be a cause of the female-biased movement. Studies of dispersal using data from DNA markers and tagging-recapture in hermaphroditic fish species could enhance our understanding of patterns of dispersal in fish. PMID:22701591
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Yue, Gen Hua; Xia, Jun Hong; Liu, Feng; Lin, Grace
2012-01-01
Movement of individuals influences individual reproductive success, fitness, genetic diversity and relationships among individuals within populations and gene exchange among populations. Competition between males or females for mating opportunities and/or local resources predicts a female bias in taxa with monogamous mating systems and a male-biased dispersal in polygynous species. In birds and mammals, the patterns of dispersal between sexes are well explored, while dispersal patterns in protandrous hermaphroditic fish species have not been studied. We collected 549 adult individuals of Asian seabass (Lates calcarifer) from four locations in the South China Sea. To assess the difference in patterns of dispersal between sexes, we genotyped all individuals with 18 microsatellites. Significant genetic differentiation was detected among and within sampling locations. The parameters of population structure (F(ST)), relatedness (r) and the mean assignment index (mAIC), in combination with data on tagging-recapture, supplied strong evidences for female-biased dispersal in the Asian seabass. This result contradicts our initial hypothesis of no sex difference in dispersal. We suggest that inbreeding avoidance of females, female mate choice under the condition of low mate competition among males, and male resource competition create a female-biased dispersal. The bigger body size of females may be a cause of the female-biased movement. Studies of dispersal using data from DNA markers and tagging-recapture in hermaphroditic fish species could enhance our understanding of patterns of dispersal in fish.
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Pellegrino, Ana Cristina; Peñaflor, Maria Fernanda Gomes Villalba; Nardi, Cristiane; Bezner-Kerr, Wayne; Guglielmo, Christopher G; Bento, José Maurício Simões; McNeil, Jeremy N
2013-01-01
Prevailing abiotic conditions may positively or negatively impact insects at both the individual and population levels. For example while moderate rainfall and wind velocity may provide conditions that favour development, as well as movement within and between habitats, high winds and heavy rains can significantly decrease life expectancy. There is some evidence that insects adjust their behaviours associated with flight, mating and foraging in response to changes in barometric pressure. We studied changes in different mating behaviours of three taxonomically unrelated insects, the curcurbit beetle, Diabrotica speciosa (Coleoptera), the true armyworm moth, Pseudaletia unipuncta (Lepidoptera) and the potato aphid, Macrosiphum euphorbiae (Hemiptera), when subjected to natural or experimentally manipulated changes in atmospheric pressure. In response to decreasing barometric pressure, male beetles exhibited decreased locomotory activity in a Y-tube olfactometer with female pheromone extracts. However, when placed in close proximity to females, they exhibited reduced courtship sequences and the precopulatory period. Under the same situations, females of the true armyworm and the potato aphid exhibited significantly reduced calling behaviour. Neither the movement of male beetles nor the calling of armyworm females differed between stable and increasing atmospheric pressure conditions. However, in the case of the armyworm there was a significant decrease in the incidence of mating under rising atmospheric conditions, suggesting an effect on male behaviour. When atmospheric pressure rose, very few M. euphorbiae oviparae called. This was similar to the situation observed under decreasing conditions, and consequently very little mating was observed in this species except under stable conditions. All species exhibited behavioural modifications, but there were interspecific differences related to size-related flight ability and the diel periodicity of mating activity. We postulate that the observed behavioral modifications, especially under decreasing barometric pressure would reduce the probability of injury or death under adverse weather conditions.
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Feeding ecology of breeding gadwalls on saline wetlands
Serie, J.R.; Swanson, G.A.
1976-01-01
The feeding ecology of breeding gadwalls (Anas strepera) from saline wetlands in North Dakota was examined in relation to sex, pair mates, reproductive status, food availability, and wetland type during the spring and summer of 1971 and 1972. Esophagi of males and females contained 40.4 and 48.2 percent animal food, respectively, between 17 April and 25 August. Animal foods consumed by paired females varied with reproductive condition and were independent of their mates. Invertebrates increased from 47.7 i?? 17.4 percent in the diet during prelaying to 72.0 i?? 18.4 percent during laying and declined to 46.3 i?? 30.0 percent during postlaying. Aquatic insects dominated the diet during egg-laying and were selected disproportionately relative to their availability. Esophageal contents indicated that diversity of plant and animal foods in the diet varied inversely with specific conductance. Major factors influencing food selection of the breeding birds are discussed as interactions among their physiological status, their anatomical and behavioral characteristics, and the abundance and behavior of food organisms as influenced by chemical and physical features of the environment. The data suggested that these interrelated ecological factors act simultaneously to control the phenology of events and determine the foods utilized.
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ERIC Educational Resources Information Center
Stone, Emily A.; Shackelford, Todd K.; Buss, David M.
2012-01-01
This study tests the hypothesis presented by Penke, Denissen, and Miller (2007a) that condition-dependent traits, including intelligence, attractiveness, and health, are universally and uniformly preferred as characteristics in a mate relative to traits that are less indicative of condition, including personality traits. We analyzed…
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Dating Choices of High School Students
ERIC Educational Resources Information Center
Hansen, Sally L.
1977-01-01
Dating is experienced by most adolescents in our society as a prelude to mate selection. White and black youth (N=354) were studied to measure their dating-mating choices. Implications for teachers and practitioners, based on racial and gender differences, as well as perceived peer group influences are discussed. (Author)
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USDA-ARS?s Scientific Manuscript database
Host plant chemicals can influence sex pheromone communication of tephritid fruit flies, and affect strategies optimizing mating and reproduction. Previous studies suggest that females of the South American fruit fly, Anastrepha fraterculus, prefer to mate with laboratory males previously exposed to...
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EVOLUTION OF DIVERGENT FEMALE MATING PREFERENCE IN RESPONSE TO EXPERIMENTAL SEXUAL SELECTION
Debelle, Allan; Ritchie, Michael G; Snook, Rhonda R
2014-01-01
Sexual selection is predicted to drive the coevolution of mating signals and preferences (mating traits) within populations, and could play a role in speciation if sexual isolation arises due to mating trait divergence between populations. However, few studies have demonstrated that differences in mating traits between populations result from sexual selection alone. Experimental evolution is a promising approach to directly examine the action of sexual selection on mating trait divergence among populations. We manipulated the opportunity for sexual selection (low vs. high) in populations of Drosophila pseudoobscura. Previous studies on these experimental populations have shown that sexual selection manipulation resulted in the divergence between sexual selection treatments of several courtship song parameters, including interpulse interval (IPI) which markedly influences male mating success. Here, we measure female preference for IPI using a playback design to test for preference divergence between the sexual selection treatments after 130 generations of experimental sexual selection. The results suggest that female preference has coevolved with male signal, in opposite directions between the sexual selection treatments, providing direct evidence of the ability of sexual selection to drive the divergent coevolution of mating traits between populations. We discuss the implications in the context sexual selection and speciation. PMID:24931497
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SEXUAL SELECTION THROUGH FEMALE CHOICE IN LAWES' PAROTIA, A LEK-MATING BIRD OF PARADISE.
Pruett-Jones, S G; Pruett-Jones, M A
1990-05-01
We studied sexual selection in Lawes' Parotia, a lek-mating bird of paradise, during 1981-1983 in Papua New Guinea. There was a high variance in mating success among males, with fewer than half of the individuals mating in any one year. This variance was independent of male-male interactions and disruptions. A role of female choice in sexual selection was suggested by the patterns of female visitation to courts and statistical correlations across males between phenotypic traits and mating success. Females repeatedly visited most males in their home ranges and began visiting males up to six weeks before mating. In one or more years, six aspects of male behavior and one morphological variable were positively correlated with mating success, but the probability values were not significant using a simultaneous inference test. Calculation of combined probability values across all three years revealed that one aspect of male display behavior, the probability of display, positively and significantly influenced mating status. The probability of display was also significantly correlated with relative mating success among males. Females showed strong fidelity to mates, both within and between seasons. Display sites of male Lawes' Parotia are variably dispersed, but mating success did not differ for grouped and solitary males. These data confirm an important role of female choice in sexual selection in birds of paradise but also suggest that female choice may be unrelated to the process of lek-initiation in this species. © 1990 The Society for the Study of Evolution.
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Social interactions predict genetic diversification: an experimental manipulation in shorebirds.
Cunningham, Charles; Parra, Jorge E; Coals, Lucy; Beltrán, Marcela; Zefania, Sama; Székely, Tamás
2018-01-01
Mating strategy and social behavior influence gene flow and hence affect levels of genetic differentiation and potentially speciation. Previous genetic analyses of closely related plovers Charadrius spp. found strikingly different population genetic structure in Madagascar: Kittlitz's plovers are spatially homogenous whereas white-fronted plovers have well segregated and geographically distinct populations. Here, we test the hypotheses that Kittlitz's plovers are spatially interconnected and have extensive social interactions that facilitate gene flow, whereas white-fronted plovers are spatially discrete and have limited social interactions. By experimentally removing mates from breeding pairs and observing the movements of mate-searching plovers in both species, we compare the spatial behavior of Kittlitz's and white-fronted plovers within a breeding season. The behavior of experimental birds was largely consistent with expectations: Kittlitz's plovers travelled further, sought new mates in larger areas, and interacted with more individuals than white-fronted plovers, however there was no difference in breeding dispersal. These results suggest that mating strategies, through spatial behavior and social interactions, are predictors of gene flow and thus genetic differentiation and speciation. Our study highlights the importance of using social behavior to understand gene flow. However, further work is needed to investigate the relative importance of social structure, as well as intra- and inter-season dispersal, in influencing the genetic structures of populations.
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Bachmann, Guillermo E.; Segura, Diego F.; Devescovi, Francisco; Juárez, M. Laura; Ruiz, M. Josefina; Vera, M. Teresa; Cladera, Jorge L.; Fernández, Patricia C.
2015-01-01
Background Plant chemicals can affect reproductive strategies of tephritid fruit flies by influencing sex pheromone communication and increasing male mating competitiveness. Objective and Methodology We explored whether exposure of Anastrepha fraterculus males to guava fruit volatiles and to a synthetic blend of volatile compounds released by this fruit affects the sexual performance of wild and laboratory flies. By means of bioassays and pheromone collection we investigated the mechanism underlying this phenomenon. Results Guava volatile exposure enhanced male mating success and positively affected male calling behavior and pheromone release in laboratory and wild males. Changes in male behavior appear to be particularly important during the initial phase of the sexual activity period, when most of the mating pairs are formed. Exposure of laboratory males to a subset of guava fruit volatiles enhanced mating success, showing that the response to the fruit might be mimicked artificially. Conclusions Volatiles of guava seem to influence male mating success through an enhancement of chemical and physical signals related to the communication between sexes. This finding has important implications for the management of this pest species through the Sterile Insect Technique. We discuss the possibility of using artificial blends to improve the sexual competitiveness of sterile males. PMID:25923584
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A nonsemen copulatory fluid influences the outcome of sperm competition in Japanese quail.
Finseth, F R; Iacovelli, S R; Harrison, R G; Adkins-Regan, E K
2013-09-01
Sperm competition is a powerful and widespread evolutionary force that drives the divergence of behavioural, physiological and morphological traits. Elucidating the mechanisms governing differential fertilization success is a fundamental question of sperm competition. Both sperm and nonsperm ejaculate components can influence sperm competition outcomes. Here, we investigate the role of a nonsemen copulatory fluid in sperm competition. Male Japanese quail possess a gland that makes meringue-like foam. Males produce and store foam independent of sperm and seminal fluid, yet transfer foam to females during copulation. We tested whether foam influenced the outcome of sperm competition by varying foam state and mating order in competitive matings. We found that the presence of foam from one male decreased the relative fertilization success of a rival, and that foam from a given male increased the probability he obtained any fertilizations. Mating order also affected competitive success. Males mated first fertilized proportionally more eggs in a clutch and had more matings with any fertilizations than subsequent males. We conclude that the function of foam in sperm competition is mediated through the positive interaction of foam with a male's sperm, and we speculate whether the benefit is achieved through improving sperm storage, fertilizing efficiency or retention. Our results suggest males can evolve complex strategies to gain fertilizations at the expense of rivals as foam, a copulatory fluid not required for fertilization, nevertheless, has important effects on reproductive performance under competition. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.
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Hurford, Amy; Hebblewhite, Mark; Lewis, Mark A
2006-11-01
A reduced probability of finding mates at low densities is a frequently hypothesized mechanism for a component Allee effect. At low densities dispersers are less likely to find mates and establish new breeding units. However, many mathematical models for an Allee effect do not make a distinction between breeding group establishment and subsequent population growth. Our objective is to derive a spatially explicit mathematical model, where dispersers have a reduced probability of finding mates at low densities, and parameterize the model for wolf recolonization in the Greater Yellowstone Ecosystem (GYE). In this model, only the probability of establishing new breeding units is influenced by the reduced probability of finding mates at low densities. We analytically and numerically solve the model to determine the effect of a decreased probability in finding mates at low densities on population spread rate and density. Our results suggest that a reduced probability of finding mates at low densities may slow recolonization rate.
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Dynamics of cell wall elasticity pattern shapes the cell during yeast mating morphogenesis.
Goldenbogen, Björn; Giese, Wolfgang; Hemmen, Marie; Uhlendorf, Jannis; Herrmann, Andreas; Klipp, Edda
2016-09-01
The cell wall defines cell shape and maintains integrity of fungi and plants. When exposed to mating pheromone, Saccharomyces cerevisiae grows a mating projection and alters in morphology from spherical to shmoo form. Although structural and compositional alterations of the cell wall accompany shape transitions, their impact on cell wall elasticity is unknown. In a combined theoretical and experimental approach using finite-element modelling and atomic force microscopy (AFM), we investigated the influence of spatially and temporally varying material properties on mating morphogenesis. Time-resolved elasticity maps of shmooing yeast acquired with AFM in vivo revealed distinct patterns, with soft material at the emerging mating projection and stiff material at the tip. The observed cell wall softening in the protrusion region is necessary for the formation of the characteristic shmoo shape, and results in wider and longer mating projections. The approach is generally applicable to tip-growing fungi and plants cells. © 2016 The Authors.
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Pleiotropic Effects of DDT Resistance on Male Size and Behaviour.
Rostant, Wayne G; Bowyer, Jemima; Coupland, Jack; Facey, James; Hosken, David J; Wedell, Nina
2017-07-01
Understanding the evolution and spread of insecticide resistance requires knowing the relative fitness of resistant organisms. In the absence of insecticides, resistance is predicted to be costly. The Drosophila melanogaster DDT resistance allele (DDT-R) is associated with a male mating cost. This could be because resistant males are generally smaller, but DDT-R may also alter courtship behaviours. Here we tested for body size and courtship effects of DDT-R on mating success in competitive and non-competitive mating trials respectively. We also assessed relative aggression in resistant and susceptible males because aggression can also influence mating success. While the effect of DDT-R on male size partly contributed to reduced mating success, resistant males also had lower rates of courtship and were less aggressive than susceptible males. These differences contribute to the observed DDT-R mating costs. Additionally, these pleiotropic effects of DDT-R are consistent with the history and spread of resistance alleles in nature.
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The influence of pleiotropy between viability and pollen fates on mating system evolution.
Jordan, Crispin Y
2015-02-01
Floral displays are functionally and genetically integrated structures, so modifications to display will likely affect multiple fitness components (pleiotropy), including pollen export and self-pollination, and therefore selfing rate. Consequently, the great diversities of floral displays and of mating systems found among angiosperms have likely co-evolved. I extend previous models of mating system evolution to determine how pleiotropy that links viability (e.g., probability of survival to reproduction) and the allocation of pollen for export and selfing affects the evolution of selfing, outcrossing, and in particular, mixed mating. I show that the outcome depends on how pollen shifts from being exported, unused, or used for selfing. Furthermore, pleiotropy that affects viability can explain observations not addressed by previous theory, including the evolution of mixed mating despite high inbreeding depression in the absence of pollen-limitation. Therefore, pleiotropy may play a key role in explaining selfing rates for such species that exhibit otherwise enigmatic mating systems. Copyright © 2014 Elsevier Inc. All rights reserved.
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Public information influences sperm transfer to females in sailfin molly males.
Nöbel, Sabine; Witte, Klaudia
2013-01-01
In animals, including humans, the social environment can serve as a public information network in which individuals can gather public information about the quality of potential mates by observing conspecifics during sexual interactions. The observing individual itself is also a part of this information network. When recognized by the observed conspecifics as an audience, his/her presence could influence the sexual interaction between those individuals, because the observer might be considered as a potential mate or competitor. One of the most challenging questions in sexual selection to date is how the use of public information in the context of mate choice is linked to the fitness of individuals. Here, we could show that public information influences mate-choice behaviour in sailfin molly males, Poecilia latipinna, and influences the amount of sperm males transfer to a female partner. In the presence of an audience male, males spent less time with the previously preferred, larger of two females and significantly more time with the previously non-preferred, smaller female. When males could physically interact with a female and were faced with an audience male, three audience females or no audience, males transferred significantly more sperm to a female partner in the presence of an audience male than with female audience or no audience and spent less time courting his female partner. This is the first study showing that public information use turns into fitness investment, which is the crucial factor to understand the role of public information in the dynamic processes in sexual selection.
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Marital Homophily on Illicit Drug Use among Young Adults: Assortative Mating or Marital Influence?
ERIC Educational Resources Information Center
Yamaguchi, Kazuo; Kandel, Denise
1993-01-01
Analysis of longitudinal and current survey data on 545 married/cohabiting couples found highest marital homophily for ethnicity, fertility expectations, religion, educational attainment, marital satisfaction, and illicit drug use. On drug use, data best supported a model of marital selection and assortative mating but was inconclusive concerning…
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Desire and ability: hormones and the regulation of female sexual behavior.
Wallen, K
1990-01-01
The distinction between the ability to copulate and the desire to copulate is used to understand species differences in hormonal regulation of female sexual behavior. Evidence is presented demonstrating that ovarian hormones modulate female sexual motivation in both rodent and primate females. The thesis is developed that rodent females differ from primate females primarily in their dependence upon hormones for the ability to mate. Thus, apparent differences between the two groups of females in the extent to which hormones control copulatory behavior does not stem from differences in hormonal regulation of female sexual motivation but from the physical ability of primate, but not rodent, females to mate without hormonal stimulation. This emancipation of the ability to copulate from hormonal influence makes female sexual motivation the primary regulator of mating in primates. Dependence upon female sexual motivation means that the copulatory behavior of primate females is easily influenced by their physical and social environment. Because primate females can mate without hormonal input, female sexual initiation, not copulation, is argued to be the only valid indicator of female sexual motivation.
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Boardley, Ian D; Kavussanu, Maria
2009-06-01
In this study, we examined: (a) the effects of perceived motivational climate and coaching character-building competency on prosocial and antisocial behaviours towards team-mates and opponents in field hockey and netball; (b) whether the effects of perceived character-building competency on sport behaviours are mediated by moral disengagement; and (c) whether these relationships are invariant across sport. Field hockey (n = 200) and netball (n = 179) players completed questionnaires assessing the aforementioned variables. Structural equation modelling indicated that mastery climate had positive effects on prosocial and negative effects on antisocial behaviour towards team-mates, while performance climate had a positive effect on antisocial behaviour towards team-mates. Perceived character-building competency had a positive effect on prosocial behaviour towards opponents and negative effects on the two antisocial behaviours; all of these effects were mediated by moral disengagement. No effect was found for prosocial behaviour towards team-mates. The model was largely invariant across sport. The findings aid our understanding of social influences on prosocial and antisocial behaviours in sport.
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Plough, Louis V; Moran, Amy; Marko, Peter
2014-04-16
Polyandry is a common mating strategy in animals, increasing female fitness through direct (material) and indirect (genetic) benefits. Most theories about the benefits of polyandry come from studies of terrestrial animals, which have relatively complex mating systems and behaviors; less is known about the potential benefits of polyandry in sessile marine animals, for which potential mates may be scarce and females have less control over pre-copulatory mate choice. Here, we used microsatellite markers to examine multiple paternity in natural aggregations of the Pacific gooseneck barnacle Pollicipes elegans, testing the effect of density on paternity and mate relatedness on male reproductive success. We found that multiple paternity was very common (79% of broods), with up to five fathers contributing to a brood, though power was relatively low to detect more than four fathers. Density had a significant and positive linear effect on the number of fathers siring a brood, though this relationship leveled off at high numbers of fathers, which may reflect a lack of power and/or an upper limit to polyandry in this species. Significant skew in male reproductive contribution in multiply-sired broods was observed and we found a positive and significant relationship between the proportion of offspring sired and the genetic similarity between mates, suggesting that genetic compatibility may influence reproductive success in this species. To our knowledge, this is the first study to show high levels of multiple paternity in a barnacle, and overall, patterns of paternity in P. elegans appear to be driven primarily by mate availability. Evidence of paternity bias for males with higher relatedness suggests some form of post-copulatory sexual selection is taking place, but more work is needed to determine whether it operates during or post-fertilization. Overall, our results suggest that while polyandry in P. elegans is driven by mate availability, it may also provide a mechanism for females to ensure fertilization by compatible gametes and increase reproductive success in this sessile species.
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Allainé, Dominique; Sauzet, Sandrine; Cohas, Aurélie
2016-01-01
Despite being identified an area that is poorly understood regarding the effects of climate change, behavioural responses to climatic variability are seldom explored. Climatic variability is likely to cause large inter-annual variation in the frequency of extra-pair litters produced, a widespread alternative mating tactic to help prevent, correct or minimize the negative consequences of sub-optimal mate choice. In this study, we investigated how climatic variability affects the inter-annual variation in the proportion of extra-pair litters in a wild population of Alpine marmots. During 22 years of monitoring, the annual proportion of extra-pair litters directly increased with the onset of earlier springs and indirectly with increased snow in winters. Snowier winters resulted in a higher proportion of families with sexually mature male subordinates and thus, created a social context within which extra-pair paternity was favoured. Earlier spring snowmelt could create this pattern by relaxing energetic, movement and time constraints. Further, deeper snow in winter could also contribute by increasing litter size and juvenile survival. Optimal mate choice is particularly relevant to generate adaptive genetic diversity. Understanding the influence of environmental conditions and the capacity of the individuals to cope with them is crucial within the context of rapid climate change. PMID:28003452
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Bichet, Coraline; Allainé, Dominique; Sauzet, Sandrine; Cohas, Aurélie
2016-12-28
Despite being identified an area that is poorly understood regarding the effects of climate change, behavioural responses to climatic variability are seldom explored. Climatic variability is likely to cause large inter-annual variation in the frequency of extra-pair litters produced, a widespread alternative mating tactic to help prevent, correct or minimize the negative consequences of sub-optimal mate choice. In this study, we investigated how climatic variability affects the inter-annual variation in the proportion of extra-pair litters in a wild population of Alpine marmots. During 22 years of monitoring, the annual proportion of extra-pair litters directly increased with the onset of earlier springs and indirectly with increased snow in winters. Snowier winters resulted in a higher proportion of families with sexually mature male subordinates and thus, created a social context within which extra-pair paternity was favoured. Earlier spring snowmelt could create this pattern by relaxing energetic, movement and time constraints. Further, deeper snow in winter could also contribute by increasing litter size and juvenile survival. Optimal mate choice is particularly relevant to generate adaptive genetic diversity. Understanding the influence of environmental conditions and the capacity of the individuals to cope with them is crucial within the context of rapid climate change. © 2016 The Author(s).
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Incestuous sisters: mate preference for brothers over unrelated males in Drosophila melanogaster.
Loyau, Adeline; Cornuau, Jérémie H; Clobert, Jean; Danchin, Etienne
2012-01-01
The literature is full of examples of inbreeding avoidance, while recent mathematical models predict that inbreeding tolerance or even inbreeding preference should be expected under several realistic conditions like e.g. polygyny. We investigated male and female mate preferences with respect to relatedness in the fruit fly D. melanogaster. Experiments offered the choice between a first order relative (full-sibling or parent) and an unrelated individual with the same age and mating history. We found that females significantly preferred mating with their brothers, thus supporting inbreeding preference. Moreover, females did not avoid mating with their fathers, and males did not avoid mating with their sisters, thus supporting inbreeding tolerance. Our experiments therefore add empirical evidence for inbreeding preference, which strengthens the prediction that inbreeding tolerance and preference can evolve under specific circumstances through the positive effects on inclusive fitness.
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Fungal Sex: The Basidiomycota.
Coelho, Marco A; Bakkeren, Guus; Sun, Sheng; Hood, Michael E; Giraud, Tatiana
2017-06-01
Fungi of the Basidiomycota, representing major pathogen lineages and mushroom-forming species, exhibit diverse means to achieve sexual reproduction, with particularly varied mechanisms to determine compatibilities of haploid mating partners. For species that require mating between distinct genotypes, discrimination is usually based on both the reciprocal exchange of diffusible mating pheromones, rather than sexes, and the interactions of homeodomain protein signals after cell fusion. Both compatibility factors must be heterozygous in the product of mating, and genetic linkage relationships of the mating pheromone/receptor and homeodomain genes largely determine the complex patterns of mating-type variation. Independent segregation of the two compatibility factors can create four haploid mating genotypes from meiosis, referred to as tetrapolarity. This condition is thought to be ancestral to the basidiomycetes. Alternatively, cosegregation by linkage of the two mating factors, or in some cases the absence of the pheromone-based discrimination, yields only two mating types from meiosis, referred to as bipolarity. Several species are now known to have large and highly rearranged chromosomal regions linked to mating-type genes. At the population level, polymorphism of the mating-type genes is an exceptional aspect of some basidiomycete fungi, where selection under outcrossing for rare, intercompatible allelic variants is thought to be responsible for numbers of mating types that may reach several thousand. Advances in genome sequencing and assembly are yielding new insights by comparative approaches among and within basidiomycete species, with the promise to resolve the evolutionary origins and dynamics of mating compatibility genetics in this major eukaryotic lineage.
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Gustafsson, Lars; Qvarnström, Anna
2006-02-01
According to the original "sexy son" hypothesis, a female may benefit from pairing with an already-mated male despite a reduction in fecundity because her sons inherit their father's attractiveness. We used data from a long-term study of collared flycatchers (Ficedula albicollis) collected during 24 years to test this prediction. Our results show that the sons of polygynously mated females fledged in poor condition and therefore did not inherit their father's large forehead patch (a condition-dependent display trait) or mating status. From the female's perspective, polygynous pairing resulted in fewer recruited grandchildren than did a monogamous pairing. The reproductive value of sons did not outweigh the fecundity costs of polygyny because the low paternal care reduced the attractiveness of sons. When there are long-lasting parental effects on offspring attractiveness, costs of polygyny may include the production of nonsexy sons.
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Sexual dimorphism in stature (SDS), jealousy and mate retention.
Brewer, Gayle; Riley, Charlene
2010-10-02
Previous research has investigated the manner in which absolute height impacts on jealousy and mate retention. Although relative height is also important, little information exists about the potential influence of sexual dimorphism in stature (SDS) within established relationships. The current study investigated the relationship between SDS and the satisfaction, jealousy and mate retention behaviors reported by men and women. Heterosexual men (n = 98) and women (n = 102) completed a questionnaire. Men in high SDS relationships reported the lowest levels of cognitive and behavioral jealousy, although the impact of SDS on relationship satisfaction was less clear. SDS was not associated with the overall use of mate retention strategies; SDS did however affect the use of three specific strategies (vigilance, monopolization of time, love and care). SDS did not affect women's relationship satisfaction, jealousy (cognitive, behavioral, or emotional) or the use of mate retention strategies (with the exception of resource display).
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Temporal variation in size-assortative mating and male mate choice in a spider with amphisexual care
NASA Astrophysics Data System (ADS)
Moura, Rafael R.; Gonzaga, Marcelo O.
2017-04-01
Males should be more selective when they have a high investment in reproduction, especially in species with biparental or paternal care. In this context, male mate choice can promote size-assortative mating (SAM) when (1) large males win intrasexual disputes, (2) large females are more fecund, and (3) males prefer larger females to smaller ones. In the spider Manogea porracea, males exhibit high reproductive investment by building their webs above those of females and exhibiting extended care of offspring in the absence of females. Under these circumstances, we expect the occurrence of SAM and male preference for large females. Herein, we performed observations and experiments in the field to evaluate the hypotheses that (1) M. porracea mates assortatively by size and (2) SAM is influenced by male mate choice. Furthermore, we measured variables that could affect mating patterns, the sex ratios, and densities of both sexes. Pairing in M. porracea was positively size-assortative in 2012, but not in 2013. Large males won most disputes for mates and preferred larger females, which produced more eggs. The inconsistency in detection of SAM was due to population dynamics, namely variations in sex ratio and population density across the breeding season. Furthermore, we found that the significance of male mate choice on sexual selection of body size in M. porracea strongly depends on the competition intensity for mating opportunities. The traditional sexual selection hypothesis of SAM needs to be reviewed and must include measures of competition intensity.
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Stopher, K V; Nussey, D H; Clutton-Brock, T H; Guinness, F; Morris, A; Pemberton, J M
2012-01-01
The interaction between philopatry and nonrandom mating has important consequences for the genetic structure of populations, influencing co-ancestry within social groups but also inbreeding. Here, using genetic paternity data, we describe mating patterns in a wild population of red deer (Cervus elaphus) which are associated with marked consequences for co-ancestry and inbreeding in the population. Around a fifth of females mate with a male with whom they have mated previously, and further, females frequently mate with a male with whom a female relative has also mated (intralineage polygyny). Both of these phenomena occur more than expected under random mating. Using simulations, we demonstrate that temporal and spatial factors, as well as skew in male breeding success, are important in promoting both re-mating behaviours and intralineage polygyny. However, the information modelled was not sufficient to explain the extent to which these behaviours occurred. We show that re-mating and intralineage polygyny are associated with increased pairwise relatedness in the population and a rise in average inbreeding coefficients. In particular, the latter resulted from a correlation between male relatedness and rutting location, with related males being more likely to rut in proximity to one another. These patterns, alongside their consequences for the genetic structure of the population, have rarely been documented in wild polygynous mammals, yet they have important implications for our understanding of genetic structure, inbreeding avoidance and dispersal in such systems. PMID:23039875
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Mating flights select for symmetry in honeybee drones ( Apis mellifera)
NASA Astrophysics Data System (ADS)
Jaffé, Rodolfo; Moritz, Robin F. A.
2010-03-01
Males of the honeybee ( Apis mellifera) fly to specific drone congregation areas (DCAs), which virgin queens visit in order to mate. From the thousands of drones that are reared in a single colony, only very few succeed in copulating with a queen, and therefore, a strong selection is expected to act on adult drones during their mating flights. In consequence, the gathering of drones at DCAs may serve as an indirect mate selection mechanism, assuring that queens only mate with those individuals having a better flight ability and a higher responsiveness to the queen’s visual and chemical cues. Here, we tested this idea relying on wing fluctuating asymmetry (FA) as a measure of phenotypic quality. By recapturing marked drones at a natural DCA and comparing their size and FA with a control sample of drones collected at their maternal hives, we were able to detect any selection on wing size and wing FA occurring during the mating flights. Although we found no solid evidence for selection on wing size, wing FA was found to be significantly lower in the drones collected at the DCA than in those collected at the hives. Our results demonstrate the action of selection during drone mating flights for the first time, showing that developmental stability can influence the mating ability of honeybee drones. We therefore conclude that selection during honeybee drone mating flights may confer some fitness advantages to the queens.
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Mating flights select for symmetry in honeybee drones (Apis mellifera).
Jaffé, Rodolfo; Moritz, Robin F A
2010-03-01
Males of the honeybee (Apis mellifera) fly to specific drone congregation areas (DCAs), which virgin queens visit in order to mate. From the thousands of drones that are reared in a single colony, only very few succeed in copulating with a queen, and therefore, a strong selection is expected to act on adult drones during their mating flights. In consequence, the gathering of drones at DCAs may serve as an indirect mate selection mechanism, assuring that queens only mate with those individuals having a better flight ability and a higher responsiveness to the queen's visual and chemical cues. Here, we tested this idea relying on wing fluctuating asymmetry (FA) as a measure of phenotypic quality. By recapturing marked drones at a natural DCA and comparing their size and FA with a control sample of drones collected at their maternal hives, we were able to detect any selection on wing size and wing FA occurring during the mating flights. Although we found no solid evidence for selection on wing size, wing FA was found to be significantly lower in the drones collected at the DCA than in those collected at the hives. Our results demonstrate the action of selection during drone mating flights for the first time, showing that developmental stability can influence the mating ability of honeybee drones. We therefore conclude that selection during honeybee drone mating flights may confer some fitness advantages to the queens.
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Liu, Xiao Hui; Yue, Ling Fen; Wang, Da Wei; Li, Ning; Cong, Lin
2013-01-01
Inbreeding depression is a major evolutionary and ecological force influencing population dynamics and the evolution of inbreeding-avoidance traits such as mating systems and dispersal. Mating systems and dispersal are fundamental determinants of population genetic structure. Resolving the relationships among genetic structure, seasonal breeding-related mating systems and dispersal will facilitate our understanding of the evolution of inbreeding avoidance. The goals of this study were as follows: (i) to determine whether females actively avoided mating with relatives in a group-living rodent species, Brandt’s voles (Lasiopodomys brandtii), by combined analysis of their mating system, dispersal and genetic structure; and (ii) to analyze the relationships among the variation in fine-genetic structure, inbreeding avoidance, season-dependent mating strategies and individual dispersal. Using both individual- and population-level analyses, we found that the majority of Brandt’s vole groups consisted of close relatives. However, both group-specific FISs, an inbreeding coefficient that expresses the expected percentage rate of homozygosity arising from a given breeding system, and relatedness of mates showed no sign of inbreeding. Using group pedigrees and paternity analysis, we show that the mating system of Brandt’s voles consists of a type of polygyny for males and extra-group polyandry for females, which may decrease inbreeding by increasing the frequency of mating among distantly-related individuals. The consistent variation in within-group relatedness, among-group relatedness and fine-scale genetic structures was mostly due to dispersal, which primarily occurred during the breeding season. Biologically relevant variation in the fine-scale genetic structure suggests that dispersal during the mating season may be a strategy to avoid inbreeding and drive the polygynous and extra-group polyandrous mating system of this species. PMID:23516435
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Evolution of divergent female mating preference in response to experimental sexual selection.
Debelle, Allan; Ritchie, Michael G; Snook, Rhonda R
2014-09-01
Sexual selection is predicted to drive the coevolution of mating signals and preferences (mating traits) within populations, and could play a role in speciation if sexual isolation arises due to mating trait divergence between populations. However, few studies have demonstrated that differences in mating traits between populations result from sexual selection alone. Experimental evolution is a promising approach to directly examine the action of sexual selection on mating trait divergence among populations. We manipulated the opportunity for sexual selection (low vs. high) in populations of Drosophila pseudoobscura. Previous studies on these experimental populations have shown that sexual selection manipulation resulted in the divergence between sexual selection treatments of several courtship song parameters, including interpulse interval (IPI) which markedly influences male mating success. Here, we measure female preference for IPI using a playback design to test for preference divergence between the sexual selection treatments after 130 generations of experimental sexual selection. The results suggest that female preference has coevolved with male signal, in opposite directions between the sexual selection treatments, providing direct evidence of the ability of sexual selection to drive the divergent coevolution of mating traits between populations. We discuss the implications in the context sexual selection and speciation. © 2014 The Authors. Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.
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Resistance evolution to Bt crops: predispersal mating of European corn borers.
Dalecky, Ambroise; Ponsard, Sergine; Bailey, Richard I; Pélissier, Céline; Bourguet, Denis
2006-06-01
Over the past decade, the high-dose refuge (HDR) strategy, aimed at delaying the evolution of pest resistance to Bacillus thuringiensis (Bt) toxins produced by transgenic crops, became mandatory in the United States and is being discussed for Europe. However, precopulatory dispersal and the mating rate between resident and immigrant individuals, two features influencing the efficiency of this strategy, have seldom been quantified in pests targeted by these toxins. We combined mark-recapture and biogeochemical marking over three breeding seasons to quantify these features directly in natural populations of Ostrinia nubilalis, a major lepidopteran corn pest. At the local scale, resident females mated regardless of males having dispersed beforehand or not, as assumed in the HDR strategy. Accordingly, 0-67% of resident females mating before dispersal did so with resident males, this percentage depending on the local proportion of resident males (0% to 67.2%). However, resident males rarely mated with immigrant females (which mostly arrived mated), the fraction of females mating before dispersal was variable and sometimes substantial (4.8% to 56.8%), and there was no evidence for male premating dispersal being higher. Hence, O. nubilalis probably mates at a more restricted spatial scale than previously assumed, a feature that may decrease the efficiency of the HDR strategy under certain circumstances, depending for example on crop rotation practices.
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Tettamanti, Federico; Viblanc, Vincent A.
2014-01-01
During the rut, polygynous ungulates gather in mixed groups of individuals of different sex and age. Group social composition, which may vary on a daily basis, is likely to have strong influences on individual’s time-budget, with emerging properties at the group-level. To date, few studies have considered the influence of group composition on male and female behavioral time budget in mating groups. Focusing on a wild population of Alpine ibex, we investigated the influence of group composition (adult sex ratio, the proportion of dominant to subordinate males, and group size) on three behavioral axes obtained by Principal Components Analysis, describing male and female group time-budget. For both sexes, the first behavioral axis discerned a trade-off between grazing and standing/vigilance behavior. In females, group vigilance behavior increased with increasingly male-biased sex ratio, whereas in males, the effect of adult sex ratio on standing/vigilance behavior depended on the relative proportion of dominant males in the mating group. The second axis characterized courtship and male-male agonistic behavior in males, and moving and male-directed agonistic behavior in females. Mating group composition did not substantially influence this axis in males. However, moving and male-directed agonistic behavior increased at highly biased sex ratios (quadratic effect) in females. Finally, the third axis highlighted a trade-off between moving and lying behavior in males, and distinguished moving and female-female agonistic behavior from lying behavior in females. For males, those behaviors were influenced by a complex interaction between group size and adult sex ratio, whereas in females, moving and female-female agonistic behaviors increased in a quadratic fashion at highly biased sex ratios, and also increased with increasing group size. Our results reveal complex behavioral trade-offs depending on group composition in the Alpine ibex, and emphasize the importance of social factors in influencing behavioral time-budgets of wild ungulates during the rut. PMID:24416453
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Polyandry as a mediator of sexual selection before and after mating
Kvarnemo, Charlotta; Simmons, Leigh W.
2013-01-01
The Darwin–Bateman paradigm recognizes competition among males for access to multiple mates as the main driver of sexual selection. Increasingly, however, females are also being found to benefit from multiple mating so that polyandry can generate competition among females for access to multiple males, and impose sexual selection on female traits that influence their mating success. Polyandry can reduce a male's ability to monopolize females, and thus weaken male focused sexual selection. Perhaps the most important effect of polyandry on males arises because of sperm competition and cryptic female choice. Polyandry favours increased male ejaculate expenditure that can affect sexual selection on males by reducing their potential reproductive rate. Moreover, sexual selection after mating can ameliorate or exaggerate sexual selection before mating. Currently, estimates of sexual selection intensity rely heavily on measures of male mating success, but polyandry now raises serious questions over the validity of such approaches. Future work must take into account both pre- and post-copulatory episodes of selection. A change in focus from the products of sexual selection expected in males, to less obvious traits in females, such as sensory perception, is likely to reveal a greater role of sexual selection in female evolution. PMID:23339234
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Jones, Adam G; Arguello, J Roman; Arnold, Stevan J
2002-01-01
Few studies have influenced thought on the nature of sexual selection to the extent of the classic paper of A. J. Bateman on mating patterns in Drosophila. However, interpretation of his study remains controversial, and a lack of modern empirical evidence prevents a consensus with respect to the perceived utility of Bateman's principles in the study of sexual selection. Here, we use a genetic study of natural mating patterns in the rough-skinned newt, Taricha granulosa, to investigate the concordance between Bateman's principles and the intensity of sexual selection. We found that males experienced strong sexual selection on tail height and body size, while sexual selection was undetectable in females. This direct quantification of sexual selection agreed perfectly with inferences that are based on Bateman's principles. Specifically, males (in comparison with females) exhibited greater standardized variances in reproductive and mating success, as well as a stronger relationship between mating success and reproductive success. Overall, our results illustrate that Bateman's principles provide the only quantitative measures of the mating system with explicit connections to formal selection theory and should be the central focus of studies of mating patterns in natural populations. PMID:12573067
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Bowman, Elizabeth; Tatar, Marc
2016-10-27
BACKGROUND: The ratio of protein to carbohydrate (P:C) consumed influences reproduction and lifespan, outcomes that are often maximized by different P:C intake. OBJECTIVE: Determine if reproduction in female Drosophila drives elevated P:C intake. Distinguish whether such a preference is driven by egg production or from male-derived sex peptides in seminal fluid. METHODS: Intake of protein and carbohydrate was measured in a diet-choice assay. Macronutrient intake was calculated for mated and unmated fertile females, mated and unmated sterile females, and both types of female when mated to wildtype males and to males lacking sex peptide. RESULTS: Mated females have high P:C intake relative to unmated females and mated, sterile females. Fertile females mated to wildtype males and to males lacking sex peptide have high P:C intake, but sterile females have similar, low P:C intake when unmated and when mated to males lacking sex peptide. CONCLUSIONS: The metabolic demands of egg production and sex peptides are individually sufficient to drive elevated P:C intake in adult female Drosophila. Reproductive state can thus modulate how animals consume macronutrients, which in turn can impact their health and aging.
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Bowman, Elizabeth; Tatar, Marc
2016-01-01
BACKGROUND: The ratio of protein to carbohydrate (P:C) consumed influences reproduction and lifespan, outcomes that are often maximized by different P:C intake. OBJECTIVE: Determine if reproduction in female Drosophila drives elevated P:C intake. Distinguish whether such a preference is driven by egg production or from male-derived sex peptides in seminal fluid. METHODS: Intake of protein and carbohydrate was measured in a diet-choice assay. Macronutrient intake was calculated for mated and unmated fertile females, mated and unmated sterile females, and both types of female when mated to wildtype males and to males lacking sex peptide. RESULTS: Mated females have high P:C intake relative to unmated females and mated, sterile females. Fertile females mated to wildtype males and to males lacking sex peptide have high P:C intake, but sterile females have similar, low P:C intake when unmated and when mated to males lacking sex peptide. CONCLUSIONS: The metabolic demands of egg production and sex peptides are individually sufficient to drive elevated P:C intake in adult female Drosophila. Reproductive state can thus modulate how animals consume macronutrients, which in turn can impact their health and aging. PMID:28035342
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Polyandry as a mediator of sexual selection before and after mating.
Kvarnemo, Charlotta; Simmons, Leigh W
2013-03-05
The Darwin-Bateman paradigm recognizes competition among males for access to multiple mates as the main driver of sexual selection. Increasingly, however, females are also being found to benefit from multiple mating so that polyandry can generate competition among females for access to multiple males, and impose sexual selection on female traits that influence their mating success. Polyandry can reduce a male's ability to monopolize females, and thus weaken male focused sexual selection. Perhaps the most important effect of polyandry on males arises because of sperm competition and cryptic female choice. Polyandry favours increased male ejaculate expenditure that can affect sexual selection on males by reducing their potential reproductive rate. Moreover, sexual selection after mating can ameliorate or exaggerate sexual selection before mating. Currently, estimates of sexual selection intensity rely heavily on measures of male mating success, but polyandry now raises serious questions over the validity of such approaches. Future work must take into account both pre- and post-copulatory episodes of selection. A change in focus from the products of sexual selection expected in males, to less obvious traits in females, such as sensory perception, is likely to reveal a greater role of sexual selection in female evolution.
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Gilroy, James J; Lockwood, Julie L
2012-01-01
Dispersal is a critically important process in ecology, but robust predictive models of animal dispersal remain elusive. We identify a potentially ubiquitous component of variation in animal dispersal that has been largely overlooked until now: the influence of mate encounters on settlement probability. We use an individual-based model to simulate dispersal in sexually-reproducing organisms that follow a simple set of movement rules based on conspecific encounters, within an environment lacking spatial habitat heterogeneity. We show that dispersal distances vary dramatically with fluctuations in population density in such a model, even in the absence of variation in dispersive traits between individuals. In a simple random-walk model with promiscuous mating, dispersal distributions become increasingly 'fat-tailed' at low population densities due to the increasing scarcity of mates. Similar variation arises in models incorporating territoriality. In a model with polygynous mating, we show that patterns of sex-biased dispersal can even be reversed across a gradient of population density, despite underlying dispersal mechanisms remaining unchanged. We show that some widespread dispersal patterns found in nature (e.g. fat tailed distributions) can arise as a result of demographic variability in the absence of heterogeneity in dispersive traits across the population. This implies that models in which individual dispersal distances are considered to be fixed traits might be unrealistic, as dispersal distances vary widely under a single dispersal mechanism when settlement is influenced by mate encounters. Mechanistic models offer a promising means of advancing our understanding of dispersal in sexually-reproducing organisms.
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The evolution of conditional dispersal and reproductive isolation along environmental gradients
Payne, Joshua L.; Mazzucco, Rupert; Dieckmann, Ulf
2011-01-01
Dispersal modulates gene flow throughout a population’s spatial range. Gene flow affects adaptation at local spatial scales, and consequently impacts the evolution of reproductive isolation. A recent theoretical investigation has demonstrated that local adaptation along an environmental gradient, facilitated by the evolution of limited dispersal, can lead to parapatric speciation even in the absence of assortative mating. This and other studies assumed unconditional dispersal, so individuals start dispersing without regard to local environmental conditions. However, many species disperse conditionally; their propensity to disperse is contingent upon environmental cues, such as the degree of local crowding or the availability of suitable mates. Here, we use an individual-based model in continuous space to investigate by numerical simulation the relationship between the evolution of threshold-based conditional dispersal and parapatric speciation driven by frequency-dependent competition along environmental gradients. We find that, as with unconditional dispersal, parapatric speciation occurs under a broad range of conditions when reproduction is asexual, and under a more restricted range of conditions when reproduction is sexual. In both the asexual and sexual cases, the evolution of conditional dispersal is strongly influenced by the slope of the environmental gradient: shallow environmental gradients result in low dispersal thresholds and high dispersal distances, while steep environmental gradients result in high dispersal thresholds and low dispersal distances. The latter, however, remain higher than under unconditional dispersal, thus undermining isolation by distance, and hindering speciation in sexual populations. Consequently, the speciation of sexual populations under conditional dispersal is triggered by a steeper gradient than under unconditional dispersal. Enhancing the disruptiveness of frequency-dependent selection, more box-shaped competition kernels dramatically lower the speciation-enabling slope of the environmental gradient. PMID:21194533
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The evolution of conditional dispersal and reproductive isolation along environmental gradients.
Payne, Joshua L; Mazzucco, Rupert; Dieckmann, Ulf
2011-03-21
Dispersal modulates gene flow throughout a population's spatial range. Gene flow affects adaptation at local spatial scales, and consequently impacts the evolution of reproductive isolation. A recent theoretical investigation has demonstrated that local adaptation along an environmental gradient, facilitated by the evolution of limited dispersal, can lead to parapatric speciation even in the absence of assortative mating. This and other studies assumed unconditional dispersal, so individuals start dispersing without regard to local environmental conditions. However, many species disperse conditionally; their propensity to disperse is contingent upon environmental cues, such as the degree of local crowding or the availability of suitable mates. Here, we use an individual-based model in continuous space to investigate by numerical simulation the relationship between the evolution of threshold-based conditional dispersal and parapatric speciation driven by frequency-dependent competition along environmental gradients. We find that, as with unconditional dispersal, parapatric speciation occurs under a broad range of conditions when reproduction is asexual, and under a more restricted range of conditions when reproduction is sexual. In both the asexual and sexual cases, the evolution of conditional dispersal is strongly influenced by the slope of the environmental gradient: shallow environmental gradients result in low dispersal thresholds and high dispersal distances, while steep environmental gradients result in high dispersal thresholds and low dispersal distances. The latter, however, remain higher than under unconditional dispersal, thus undermining isolation by distance, and hindering speciation in sexual populations. Consequently, the speciation of sexual populations under conditional dispersal is triggered by a steeper gradient than under unconditional dispersal. Enhancing the disruptiveness of frequency-dependent selection, more box-shaped competition kernels dramatically lower the speciation-enabling slope of the environmental gradient. Copyright © 2010 Elsevier Ltd. All rights reserved.
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Ultraviolet reflectance by the cere of raptors
Mougeot, François; Arroyo, Beatriz E
2006-01-01
Ultraviolet (UV) signals have been shown to play key roles in social and sexual signalling in birds. Using a spectrophotometer, we analysed the colour of the cere (skin above the beak) of a diurnal raptor, the Montagu's harrier (Circus pygargus), and show that it reflects in the UV part of the spectrum. The cere is a well-known sexual signal in raptors, with carotenoid based pigmentation being indicative of quality. We thus hypothesized that UV reflectance also signals quality. Accordingly, we found that in our sample of wild males, the location of the UV peak was related to the orangeness of cere and correlated with male body mass and condition (mass corrected for size). Also, males with brighter UV were mated to females that laid earlier, as expected if UV reflectance relates to a male's quality and attractiveness. Future studies should investigate the relationships between UV reflectance and carotenoid pigmentation of cere, and test how UV reflectance influences mate choice. PMID:17148356
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Drayton, J M; Hunt, J; Brooks, R; Jennions, M D
2007-05-01
If male sexual signalling is honest because it captures genetic variation in condition then traits that are important mate choice cues should be disproportionately affected by inbreeding relative to other traits. To test this, we investigated the effect of brother-sister mating on advertisement calling by male field crickets Teleogryllus commodus. We quantified the effect of one generation of inbreeding on nightly calling effort and five finer-scale aspects of call structure that have been shown to influence attractiveness. We also quantified inbreeding depression on six life history traits and one morphological trait. Inbreeding significantly reduced hatching success, nymph survival and adult lifespan but had no detectable effect on hatching rate, developmental rate or adult body mass. The effect of inbreeding on sexually selected traits was equivocal. There was no decline in calling effort (seconds of sound production/night) by inbred males, but there were highly significant changes in three of five finer-scale call parameters. Sexually selected traits clearly vary in their susceptibility to inbreeding depression.
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Learning and discrimination of cuticular hydrocarbons in a social insect
van Wilgenburg, Ellen; Felden, Antoine; Choe, Dong-Hwan; Sulc, Robert; Luo, Jun; Shea, Kenneth J.; Elgar, Mark A.; Tsutsui, Neil D.
2012-01-01
Social insect cuticular hydrocarbon (CHC) mixtures are among the most complex chemical cues known and are important in nest-mate, caste and species recognition. Despite our growing knowledge of the nature of these cues, we have very little insight into how social insects actually perceive and discriminate among these chemicals. In this study, we use the newly developed technique of differential olfactory conditioning to pure, custom-designed synthetic colony odours to analyse signal discrimination in Argentine ants, Linepithema humile. Our results show that tri-methyl alkanes are more easily learned than single-methyl or straight-chain alkanes. In addition, we reveal that Argentine ants can discriminate between hydrocarbons with different branching patterns and the same chain length, but not always between hydrocarbons with the same branching patterns but different chain length. Our data thus show that biochemical characteristics influence those compounds that ants can discriminate between, and which thus potentially play a role in chemical signalling and nest-mate recognition. PMID:21831880
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Incestuous Sisters: Mate Preference for Brothers over Unrelated Males in Drosophila melanogaster
Loyau, Adeline; Cornuau, Jérémie H.; Clobert, Jean; Danchin, Étienne
2012-01-01
The literature is full of examples of inbreeding avoidance, while recent mathematical models predict that inbreeding tolerance or even inbreeding preference should be expected under several realistic conditions like e.g. polygyny. We investigated male and female mate preferences with respect to relatedness in the fruit fly D. melanogaster. Experiments offered the choice between a first order relative (full-sibling or parent) and an unrelated individual with the same age and mating history. We found that females significantly preferred mating with their brothers, thus supporting inbreeding preference. Moreover, females did not avoid mating with their fathers, and males did not avoid mating with their sisters, thus supporting inbreeding tolerance. Our experiments therefore add empirical evidence for inbreeding preference, which strengthens the prediction that inbreeding tolerance and preference can evolve under specific circumstances through the positive effects on inclusive fitness. PMID:23251487
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Odor Communication and Mate Choice in Rodents
Ferkin, Michael H.
2018-01-01
This paper details how chemical communication is affected by ecological challenges such as finding mates. I list several conditions that affect the decision to attract mates, the decision to respond to the signals of potential mates and how the response depends on context. These mate-choice decisions and their outcomes will depend on the life history constraints placed on individuals such as their fecundity, sex, lifespan, opportunities to mate in the future and age at senescence. Consequently, the sender’s decision to scent mark or self-groom as well as the receiver’s choice of response represents a tradeoff between the current costs of the participant’s own survival and future reproduction against that of reproducing now. The decision to scent mark and the response to the scent mark of opposite-sex conspecifics should maximize the fitness of the participants in that context. PMID:29370074
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Sociosexuality predicts women's preferences for symmetry in men's faces.
Quist, Michelle C; Watkins, Christopher D; Smith, Finlay G; Little, Anthony C; Debruine, Lisa M; Jones, Benedict C
2012-12-01
Although men displaying cues of good physical condition possess traits that are desirable in a mate (e.g., good health), these men are also more likely to possess antisocial characteristics that are undesirable in a long-term partner (e.g., aggression and tendency to infidelity). How women resolve this trade-off between the costs and benefits associated with choosing a mate in good physical condition may lead to strategic variation in women's mate preferences. Because the costs of choosing a mate with antisocial personality characteristics are greater in long- than short-term relationships, women's sociosexuality (i.e., the extent to which they are interested in uncommitted sexual relationships) may predict individual differences in their mate preferences. Here we investigated variation in 99 heterosexual women's preferences for facial symmetry, a characteristic that is thought to be an important cue of physical condition. Symmetry preferences were assessed using pairs of symmetrized and original (i.e., relatively asymmetric) versions of 10 male and 10 female faces. Analyses showed that women's sociosexuality, and their sociosexual attitude in particular, predicted their preferences for symmetry in men's, but not women's, faces; women who reported being more interested in short-term, uncommitted relationships demonstrated stronger attraction to symmetric men. Our findings present new evidence for potentially adaptive variation in women's symmetry preferences that is consistent with trade-off theories of attraction.
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The messenger matters: Pollinator functional group influences mating system dynamics.
Weber, Jennifer J
2017-08-01
The incredible diversity of plant mating systems has fuelled research in evolutionary biology for over a century. Currently, there is broad concern about the impact of rapidly changing pollinator communities on plant populations. Very few studies, however, examine patterns and mechanisms associated with multiple paternity from cross-pollen loads. Often, foraging pollinators collect a mixed pollen load that may result in the deposition of pollen from different sires to receptive stigmas. Coincident deposition of self- and cross-pollen leads to interesting mating system dynamics and has been investigated in numerous species. But, mixed pollen loads often consist of a diversity of cross-pollen and result in multiple sires of seeds within a fruit. In this issue of Molecular Ecology, Rhodes, Fant, and Skogen () examine how pollinator identity and spatial isolation influence multiple paternity within fruits of a self-incompatible evening primrose. The authors demonstrate that pollen pool diversity varies between two pollinator types, hawkmoths and diurnal solitary bees. Further, progeny from more isolated plants were less likely to have multiple sires regardless of the pollinator type. Moving forward, studies of mating system dynamics should consider the implications of multiple paternity and move beyond the self- and cross-pollination paradigm. Rhodes et al. () demonstrate the importance of understanding the roles that functionally diverse pollinators play in mating system dynamics. © 2017 John Wiley & Sons Ltd.
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Variable ecological conditions promote male helping by changing banded mongoose group composition.
Marshall, Harry H; Sanderson, Jennifer L; Mwanghuya, Francis; Businge, Robert; Kyabulima, Solomon; Hares, Michelle C; Inzani, Emma; Kalema-Zikusoka, Gladys; Mwesige, Kenneth; Thompson, Faye J; Vitikainen, Emma I K; Cant, Michael A
2016-01-01
Ecological conditions are expected to have an important influence on individuals' investment in cooperative care. However, the nature of their effects is unclear: both favorable and unfavorable conditions have been found to promote helping behavior. Recent studies provide a possible explanation for these conflicting results by suggesting that increased ecological variability, rather than changes in mean conditions, promote cooperative care. However, no study has tested whether increased ecological variability promotes individual-level helping behavior or the mechanisms involved. We test this hypothesis in a long-term study population of the cooperatively breeding banded mongoose, Mungos mungo , using 14 years of behavioral and meteorological data to explore how the mean and variability of ecological conditions influence individual behavior, body condition, and survival. Female body condition was more sensitive to changes in rainfall leading to poorer female survival and pronounced male-biased group compositions after periods of high rainfall variability. After such periods, older males invested more in helping behavior, potentially because they had fewer mating opportunities. These results provide the first empirical evidence for increased individual helping effort in more variable ecological conditions and suggest this arises because of individual differences in the effect of ecological conditions on body condition and survival, and the knock-on effect on social group composition. Individual differences in sensitivity to environmental variability, and the impacts this has on the internal structure and composition of animal groups, can exert a strong influence on the evolution and maintenance of social behaviors, such as cooperative care.
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Variable ecological conditions promote male helping by changing banded mongoose group composition
Sanderson, Jennifer L.; Mwanghuya, Francis; Businge, Robert; Kyabulima, Solomon; Hares, Michelle C.; Inzani, Emma; Kalema-Zikusoka, Gladys; Mwesige, Kenneth; Thompson, Faye J.; Vitikainen, Emma I. K.; Cant, Michael A.
2016-01-01
Ecological conditions are expected to have an important influence on individuals’ investment in cooperative care. However, the nature of their effects is unclear: both favorable and unfavorable conditions have been found to promote helping behavior. Recent studies provide a possible explanation for these conflicting results by suggesting that increased ecological variability, rather than changes in mean conditions, promote cooperative care. However, no study has tested whether increased ecological variability promotes individual-level helping behavior or the mechanisms involved. We test this hypothesis in a long-term study population of the cooperatively breeding banded mongoose, Mungos mungo, using 14 years of behavioral and meteorological data to explore how the mean and variability of ecological conditions influence individual behavior, body condition, and survival. Female body condition was more sensitive to changes in rainfall leading to poorer female survival and pronounced male-biased group compositions after periods of high rainfall variability. After such periods, older males invested more in helping behavior, potentially because they had fewer mating opportunities. These results provide the first empirical evidence for increased individual helping effort in more variable ecological conditions and suggest this arises because of individual differences in the effect of ecological conditions on body condition and survival, and the knock-on effect on social group composition. Individual differences in sensitivity to environmental variability, and the impacts this has on the internal structure and composition of animal groups, can exert a strong influence on the evolution and maintenance of social behaviors, such as cooperative care. PMID:27418750
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Mating System and Sexual Selection in the Scorpionfly Panorpa vulgaris (Mecoptera: Panorpidae)
NASA Astrophysics Data System (ADS)
Sauer, Klaus Peter; Lubjuhn, Thomas; Sindern, Jörn; Kullmann, Harald; Kurtz, Joachim; Epplen, Conny; Epplen, Jörg Thomas
1998-05-01
has become a model insect for testing theories of sexual selection. This contribution summarizes that which has been learned in recent years and presents new data that clearly show that the mating system of P. vulgaris is not simply a resource-defense polygyny, as has previously been thought. In P. vulgaris neither the pattern in food exploitation nor the ratio of variance in the lifetime reproductive success of the two sexes is in accordance with that expected in resource defense polygynous mating systems. Lifetime mating duration is the most important proximate determinant of male fitness. Males employing alternative mating tactics obtain copulations of varying duration in relation to the following sequence: saliva secretion 1 food offering 1 no gift. The number of salivary masses which males provide to females during their lifetime is significantly correlated with the lifetime condition index. The condition index depends on the fighting prowess of males and their ability to find food items. Thus saliva secretion of Panorpa is considered a Zahavian handicap, which can serve as an honest quality indicator used by mating females. Our results confirm four main predictions of the indicator model of the theory of sexual selection: (a) the indicator signals high ecological quality of its bearer, (b) the indicator value increases with phenotypic quality, (c) the indicator value is positively correlated with the genetic quality affecting offspring fitness in a natural selection context, and (d) the quality indicator is more costly for low- than for high-quality individuals. The evolutionary consequences of the mating pattern and the sperm competition mechanism in P. vulgaris are discussed in the context the way in which sexual selection creates and maintains sperm mixing and the evolution of a promiscuous mating system.
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Juárez, M. Laura; Devescovi, Francisco; Břízová, Radka; Bachmann, Guillermo; Segura, Diego F.; Kalinová, Blanka; Fernández, Patricia; Ruiz, M. Josefina; Yang, Jianquan; Teal, Peter E.A.; Cáceres, Carlos; Vreysen, Marc J.B.; Hendrichs, Jorge; Vera, M. Teresa
2015-01-01
Abstract The study of sexual behavior and the identification of the signals involved in mate recognition between con-specifics are key components that can shed some light, as part of an integrative taxonomic approach, in delimitating species within species complexes. In the Tephritidae family several species complexes have received particular attention as they include important agricultural pests such as the Ceratitis fasciventris (Bezzi), Ceratitis anonae (Graham) and Ceratitis rosa Karsch (FAR) complex, the Bactrocera dorsalis (Hendel) complex and the Anastrepha fraterculus (Wiedemann) complex. Here the value and usefulness of a methodology that uses walk-in field cages with host trees to assess, under semi-natural conditions, mating compatibility within these complexes is reviewed, and the same methodology to study the role of chemical communication in pre-mating isolation among Anastrepha fraterculus populations is used. Results showed that under the same experimental conditions it was possible to distinguish an entire range of different outcomes: from full mating compatibility among some populations to complete assortative mating among others. The effectiveness of the methodology in contributing to defining species limits was shown in two species complexes: Anastrepha fraterculus and Bactrocera dorsalis, and in the case of the latter the synonymization of several established species was published. We conclude that walk-in field cages constitute a powerful tool to measure mating compatibility, which is also useful to determine the role of chemical signals in species recognition. Overall, this experimental approach provides a good source of information about reproductive boundaries to delimit species. However, it needs to be applied as part of an integrative taxonomic approach that simultaneously assesses cytogenetic, molecular, physiological and morphological traits in order to reach more robust species delimitations. PMID:26798257
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The influence of relationship status, mate seeking, and sex on intrasexual competition.
Fisher, Maryanne L; Tran, Ulrich S; Voracek, Martin
2008-08-01
Researchers have little explored individuals' perceptions of same-sex attractiveness in terms of the influence of relationship status. By using intrasexual competition as a conceptual framework, the authors predicted that romantically involved individuals would protect their relationship by derogating competitors. Although previous researchers have strongly predicted this result, in the present study the relationship status had a negligible impact on competition, for which relationship commitment, sociosexual orientation, and self-monitoring did not account. Also, among uninvolved individuals, the authors expected those individuals seeking mates would use competitor derogation more than would those individuals not seeking mates, but there was no significant difference. Finally, because the vehicle for this investigation was attractiveness, an area in which women compete, the authors proposed that women would derogate more fiercely than would men. However, the results did not support this hypothesis either. The authors discuss future directions for research.
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Silk wrapping of nuptial gifts as visual signal for female attraction in a crepuscular spider
NASA Astrophysics Data System (ADS)
Trillo, Mariana C.; Melo-González, Valentina; Albo, Maria J.
2014-02-01
An extensive diversity of nuptial gifts is known in invertebrates, but prey wrapped in silk is a unique type of gift present in few insects and spiders. Females from spider species prefer males offering a gift accepting more and longer matings than when males offered no gift. Silk wrapping of the gift is not essential to obtain a mating, but appears to increase the chance of a mating evidencing a particularly intriguing function of this trait. Consequently, as other secondary sexual traits, silk wrapping may be an important trait under sexual selection, if it is used by females as a signal providing information on male quality. We aimed to understand whether the white color of wrapped gifts is used as visual signal during courtship in the spider Paratrechalea ornata. We studied if a patch of white paint on the males' chelicerae is attractive to females by exposing females to males: with their chelicerae painted white; without paint; and with the sternum painted white (paint control). Females contacted males with white chelicerae more often and those males obtained higher mating success than other males. Thereafter, we explored whether silk wrapping is a condition-dependent trait and drives female visual attraction. We exposed good and poor condition males, carrying a prey, to the female silk. Males in poor condition added less silk to the prey than males in good condition, indicating that gift wrapping is an indicator of male quality and may be used by females to acquire information of the potential mate.
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Adsorption of phenanthrene on activated carbon increases mineralization rate by specific bacteria.
Leglize, Pierre; Alain, Saada; Jacques, Berthelin; Corinne, Leyval
2008-03-01
Bioavailability of polycyclic aromatic hydrocarbons (PAH) in soil is affected by PAH sorption to solid phase. We studied the influence of activated carbon (AC) on phenanthrene (PHE) mineralization by five degrading bacterial strains isolated from contaminated soil. PHE adsorption on AC was important and reduced PHE aqueous concentration up to 90%. PHE degradation was improved in the presence of activated carbon with three of the bacterial strains, named NAH1, MATE3 and MATE7, which produced biofilms, whereas it was not improved with the two other ones, which did not produce biofilms, MATE10 and MATE12. Monitoring PHE distribution during incubation showed that aqueous PHE concentration was significantly higher with the biofilm-producing NAH1 than with MATE10. Bacterial adhesion on AC was also investigated. The precoating of AC with PHE increased NAH1 and MATE3 adhesion to the solid surface (>16 and >13%, respectively). Bacterial properties, such as biofilm production and adhesion to AC capacity seemed to be related to their ability to optimize PHE degradation by improving PHE diffusion and reducing diffusion path length.
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Birkás, Béla; Láng, András; Meskó, Norbert
2018-02-01
Our study investigated the different mate preferences of the Dark Triad in women. In addition to former studies, we also examined the effect of self-evaluated attractiveness on these preferences. Attractiveness is a high-valued partner attribute, especially in short-term relationships. Accordingly, we predicted that women high in Dark Triad traits prefer characteristics related to short-term mating, because they possess traits favored in short-term relationships. Associations between ideal partner standards and Dark Triad traits were investigated with self-reports: 529 female undergraduate students filled out the Short Dark Triad and the Ideal Standards Scale. Results showed that all three Dark Triad traits were related to unique preferences of mate qualities corresponding to their self-rated partner qualities. Furthermore, despite the differences between the three Dark Triad traits, women's partner preferences were associated with their self-evaluated attractiveness (an indicator of mate value). In summary, according to our findings, qualities advertised by Dark Triad women as potential partner influence their expectation or preferences regarding mates, suggesting homogamous mate choice on the levels of these qualities.
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Durante, Kristina M; Griskevicius, Vladas; Simpson, Jeffry A; Cantú, Stephanie M; Tybur, Joshua M
2012-07-01
Although the ratio of males to females in a population is known to influence behavior in nonhuman animals, little is known about how sex ratio influences human behavior. We propose that sex ratio affects women's family planning and career choices. Using both historical data and experiments, we examined how sex ratio influences women's career aspirations. Findings showed that a scarcity of men led women to seek high-paying careers and to delay starting a family. This effect was driven by how sex ratio altered the mating market, not just the job market. Sex ratios involving a scarcity of men led women to seek lucrative careers because of the difficulty women have in finding an investing, long-term mate under such circumstances. Accordingly, this low-male sex ratio produced the strongest desire for lucrative careers in women who are least able to secure a mate. These findings demonstrate that sex ratio has far-reaching effects in humans, including whether women choose briefcase over baby. PsycINFO Database Record (c) 2012 APA, all rights reserved
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Developmental Environment Effects on Sexual Selection in Male and Female Drosophila melanogaster
Morimoto, Juliano; Pizzari, Tommaso; Wigby, Stuart
2016-01-01
The developmental environment can potentially alter the adult social environment and influence traits targeted by sexual selection such as body size. In this study, we manipulated larval density in male and female Drosophila melanogaster, which results in distinct adult size phenotypes–high (low) densities for small (large) adults–and measured sexual selection in experimental groups consisting of adult males and females from high, low, or a mixture of low and high larval densities. Overall, large adult females (those reared at low larval density) had more matings, more mates and produced more offspring than small females (those reared at high larval density). The number of offspring produced by females was positively associated with their number of mates (i.e. there was a positive female Bateman gradient) in social groups where female size was experimentally varied, likely due to the covariance between female productivity and mating rate. For males, we found evidence that the larval environment affected the relative importance of sexual selection via mate number (Bateman gradients), mate productivity, paternity share, and their covariances. Mate number and mate productivity were significantly reduced for small males in social environments where males were of mixed sizes, versus social environments where all males were small, suggesting that social heterogeneity altered selection on this subset of males. Males are commonly assumed to benefit from mating with large females, but in contrast to expectations we found that in groups where both the male and female size varied, males did not gain more offspring per mating with large females. Collectively, our results indicate sex-specific effects of the developmental environment on the operation of sexual selection, via both the phenotype of individuals, and the phenotype of their competitors and mates. PMID:27167120
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Banded mongooses avoid inbreeding when mating with members of the same natal group.
Sanderson, Jennifer L; Wang, Jinliang; Vitikainen, Emma I K; Cant, Michael A; Nichols, Hazel J
2015-07-01
Inbreeding and inbreeding avoidance are key factors in the evolution of animal societies, influencing dispersal and reproductive strategies which can affect relatedness structure and helping behaviours. In cooperative breeding systems, individuals typically avoid inbreeding through reproductive restraint and/or dispersing to breed outside their natal group. However, where groups contain multiple potential mates of varying relatedness, strategies of kin recognition and mate choice may be favoured. Here, we investigate male mate choice and female control of paternity in the banded mongoose (Mungos mungo), a cooperatively breeding mammal where both sexes are often philopatric and mating between relatives is known to occur. We find evidence suggestive of inbreeding depression in banded mongooses, indicating a benefit to avoiding breeding with relatives. Successfully breeding pairs were less related than expected under random mating, which appeared to be driven by both male choice and female control of paternity. Male banded mongooses actively guard females to gain access to mating opportunities, and this guarding behaviour is preferentially directed towards less closely related females. Guard-female relatedness did not affect the guard's probability of gaining reproductive success. However, where mate-guards are unsuccessful, they lose paternity to males that are less related to the females than themselves. Together, our results suggest that both sexes of banded mongoose use kin discrimination to avoid inbreeding. Although this strategy appears to be rare among cooperative breeders, it may be more prominent in species where relatedness to potential mates is variable, and/or where opportunities for dispersal and mating outside of the group are limited. © 2015 John Wiley & Sons Ltd.
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Role of social interactions in dynamic patterns of resource patches and forager aggregation.
Tania, Nessy; Vanderlei, Ben; Heath, Joel P; Edelstein-Keshet, Leah
2012-07-10
The dynamics of resource patches and species that exploit such patches are of interest to ecologists, conservation biologists, modelers, and mathematicians. Here we consider how social interactions can create unique, evolving patterns in space and time. Whereas simple prey taxis (with consumable prey) promotes spatial uniform distributions, here we show that taxis in producer-scrounger groups can lead to pattern formation. We consider two types of foragers: those that search directly ("producers") and those that exploit other foragers to find food ("scroungers" or exploiters). We show that such groups can sustain fluctuating spatiotemporal patterns, akin to "waves of pursuit." Investigating the relative benefits to the individuals, we observed conditions under which either strategy leads to enhanced success, defined as net food consumption. Foragers that search for food directly have an advantage when food patches are localized. Those that seek aggregations of group mates do better when their ability to track group mates exceeds the foragers' food-sensing acuity. When behavioral switching or reproductive success of the strategies is included, the relative abundance of foragers and exploiters is dynamic over time, in contrast with classic models that predict stable frequencies. Our work shows the importance of considering two-way interaction--i.e., how food distribution both influences and is influenced by social foraging and aggregation of predators.
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Buggio, Laura; Vercellini, Paolo; Somigliana, Edgardo; Viganò, Paola; Frattaruolo, Maria Pina; Fedele, Luigi
2012-10-01
Female beauty has always attracted human beings. In particular, beauty has been interpreted in terms of reproductive potential and advantage in selection of mates. We have reviewed the recent literature on female facial and physical beauty with the objective of defining which parameters could influence female attractiveness. Symmetry, averageness, and sexual dimorphism with regards to facial beauty, as well as waist-to-hip ratio (WHR), breast size, and body mass index (BMI) for physical beauty, have been assessed. In current societies, it appears that facial attractiveness results from a mixture of symmetry and averageness of traits, high forehead and cheekbones, small nose and chin, full lips, thin eyebrows, and thick hair. A low WHR reliably characterized physical attractiveness, whereas inconsistencies have been observed in the evaluation of breast size and BMI. The importance of breast size appears to vary with time and sex of evaluators, whereas the impact of BMI is related to socio-economic conditions. The various hypotheses behind beauty and the role of attractiveness in mate choice and sexual selection are here described in terms of continuation of human species. Intriguing associations are emerging between features of attractiveness and some reproductive disorders, as both are substantially influenced by sex steroid hormones.
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Roberts, Thomas; Roiser, Jonathan P
2010-11-01
The human leukocyte antigen (HLA) is the most polymorphic region of the genome, coding for proteins that mediate human immune response. This polymorphism may be maintained by balancing selection and certain populations show deviations from expected gene frequencies. Supporting this hypothesis, studies into olfactory preferences have suggested that females prefer the scent of males with dissimilar HLA to their own. However, it has also been proposed that androstenones play a role in female mate choice, and as these molecules inhibit the immune system, this has implications for the theory of HLA-driven mate preference. This review will critically analyze the findings of studies investigating olfactory preference in humans, and their implications for these two contrasting theories of mate choice.
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Evolution of external female genital mutilation: why do males harm their mates?
Mouginot, Pierick; Uhl, Gabriele; Fromhage, Lutz
2017-11-01
Sperm competition may select for male reproductive traits that influence female mating or oviposition rate. These traits may induce fitness costs to the female; however, they may be costly for the males as well as any decrease in female fitness also affects male fitness. Male adaptations to sperm competition manipulate females by altering not only female behaviour or physiology, but also female morphology. In orb-weaving spiders, mating may entail mutilation of external structures of the female genitalia, which prevents genital coupling with subsequent males. Here, we present a game theoretical model showing that external female genital mutilation is favoured even under relatively high costs of mutilation, and that it is favoured by a high number of mate encounters per female and last-male sperm precedence.
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Evolution of external female genital mutilation: why do males harm their mates?
Uhl, Gabriele
2017-01-01
Sperm competition may select for male reproductive traits that influence female mating or oviposition rate. These traits may induce fitness costs to the female; however, they may be costly for the males as well as any decrease in female fitness also affects male fitness. Male adaptations to sperm competition manipulate females by altering not only female behaviour or physiology, but also female morphology. In orb-weaving spiders, mating may entail mutilation of external structures of the female genitalia, which prevents genital coupling with subsequent males. Here, we present a game theoretical model showing that external female genital mutilation is favoured even under relatively high costs of mutilation, and that it is favoured by a high number of mate encounters per female and last-male sperm precedence. PMID:29291104
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Phong, Tran Vu; Tuno, Nobuko; Kawada, Hitoshi; Takagi, Masahiro
2008-03-01
The fecundity and survival of 6 copepod species were assessed under laboratory conditions in order to choose the best candidates to control the aquatic stages of dengue mosquitoes in the field. Females of all the 6 species (Mesocyclops aspericornis, Mesocyclops pehpeiensis, Mesocyclops woutersi, Mesocyclops thermocyclopoides, Mesocyclops ogunnus, and Megacyclops viridis) mated more than once. Multiple mating resulted in increased egg production. The reproductive ability and longevity varied among the species, and M. aspericornis had the highest values. The lowest values were observed in M. thermocyclopoides. Multiple mating of males of M. aspericornis was also observed. The paternal fecundity decreased with each additional mating. There was no difference in the paternal fecundity between the males that mated at low and high female frequencies. The sperm stored in the M. aspericornis females remained viable for 30 days after storage under moist conditions at 25 degrees C or 15 degrees C. This feature in M. aspericornis represents an additional positive factor indicating that this species is a good biological agent for controlling mosquito larvae, especially in domestic water containers that may dry intermittently.
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USDA-ARS?s Scientific Manuscript database
Impaired root development caused by aluminum (Al) toxicity is a major cause for grain yield reduction for crops cultivated on acid soils which are widespread worldwide. In sorghum, the major Al tolerance locus, AltSB, is due to the function of SbMATE, which is an Al-activated root citrate transporte...
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Vasey, Paul L; Leca, Jean-Baptiste; Gunst, Noëlle; VanderLaan, Doug P
2014-10-01
In this paper, we review research related to female homosexual behavior in Japanese macaques (Macaca fuscata), including our 20-year program of research on this species. Multiple lines of evidence indicate that female homosexual behavior in this species is sexually motivated. In contrast, many sociosexual hypotheses have been tested in relation to female homosexual behavior in Japanese macaques, but none have been supported. Female Japanese macaques sometimes engage in same-sex sexual activity even when motivated opposite-sex alternatives are available. Within this context of mate choice, males compete inter-sexually for opportunities to copulate with females above and beyond any intra-sexual competition that is required. Anecdotal evidence suggests that inter-sexual competition for female sexual partners has been observed in a number of other species, including humans. At present it is unclear whether inter-sexual competition for sexual partners influences patterns of reproduction. Our understanding of sexual selection and the evolution of mating systems may be improved by investigating whether inter-sexual mate competition influences the acquisition and maintenance of reproductive partners in those species in which such interactions occur. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Lunar cycles at mating do not influence sex ratio at birth in horses.
Aguilar, J J; Cuervo-Arango, J; Santa Juliana, L
2015-02-01
It is scientifically demonstrated that lunar cycles have important effects on several biological events. Controversy exists about the lunar influence on human and animal parturition. In addition, in the horse industry, especially in Polo Horse breeders of Argentina and around the world there is a higher demand for female offspring than for males. The objective of this study was to determine whether there is a significant association between the lunar phase at the time of mating and the sex ratio at birth in horses. The Argentinean Stud Book provided information related to all matings registered for Thoroughbred and Arab horses between 2003 and 2011. Statistical associations were tested between dates of matings at different lunar phases or days and sex ratio at birth. A total of 65.535 gestations were studied. Overall, sex ratio at birth resulted in 33.396 fillies (50.96%) and 32.139 colts (49.04%). The percentages of males and females at birth were not statistically different amongst the different lunar phases or days. We can strongly conclude that managing the breeding dates in relation to lunar cycles in order to manipulate the sex ratio of the offspring is not a viable option in horses.
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Polyandry produces sexy sons at the cost of daughters in red flour beetles.
Pai, Aditi; Yan, Guiyun
2002-01-01
Female mating with multiple males within a single fertile period is a common phenomenon in the animal kingdom. Female insects are particularly promiscuous. It is not clear why females mate with multiple partners despite several potential costs, such as expenditure of time and energy, reduced lifespan, risk of predation and contracting sexually transmitted diseases. Female red flour beetles (Tribolium castaneum) obtain sufficient sperm from a single insemination to retain fertility for several months. Nonetheless they copulate repeatedly within minutes with different males despite no direct fitness benefits from this behaviour. One hypothesis is that females mate with multiple partners to provide indirect benefits via enhanced offspring fitness. To test this hypothesis, we compared the relative fitness of F(1) offspring from females mated with single males and multiple males (2, 4, 8, or 16 partners), under the condition of relatively high intraspecific competition. We found that a female mating with 16 males enhanced the relative fitness of F(1) males (in two out of three trials) but reduced F(1) females' fitness (in two independent trials) in comparison with singly mated females. We also determined whether several important fitness correlates were affected by polyandry. We found that F(1) males from mothers with 16 partners inseminated more females than F(1) males from mothers with a single partner. The viability of the eggs sired or produced by F(1) males and females from highly polyandrous mothers was also increased under conditions of low intra-specific competition. Thus, the effects of polyandry on F(1) offspring fitness depend on environmental conditions. Our results demonstrated a fitness trade-off between male and female offspring from polyandrous mothers in a competitive environment. The mechanisms and biological significance of this unique phenomenon are discussed. PMID:11886623
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Polyandry produces sexy sons at the cost of daughters in red flour beetles.
Pai, Aditi; Yan, Guiyun
2002-02-22
Female mating with multiple males within a single fertile period is a common phenomenon in the animal kingdom. Female insects are particularly promiscuous. It is not clear why females mate with multiple partners despite several potential costs, such as expenditure of time and energy, reduced lifespan, risk of predation and contracting sexually transmitted diseases. Female red flour beetles (Tribolium castaneum) obtain sufficient sperm from a single insemination to retain fertility for several months. Nonetheless they copulate repeatedly within minutes with different males despite no direct fitness benefits from this behaviour. One hypothesis is that females mate with multiple partners to provide indirect benefits via enhanced offspring fitness. To test this hypothesis, we compared the relative fitness of F(1) offspring from females mated with single males and multiple males (2, 4, 8, or 16 partners), under the condition of relatively high intraspecific competition. We found that a female mating with 16 males enhanced the relative fitness of F(1) males (in two out of three trials) but reduced F(1) females' fitness (in two independent trials) in comparison with singly mated females. We also determined whether several important fitness correlates were affected by polyandry. We found that F(1) males from mothers with 16 partners inseminated more females than F(1) males from mothers with a single partner. The viability of the eggs sired or produced by F(1) males and females from highly polyandrous mothers was also increased under conditions of low intra-specific competition. Thus, the effects of polyandry on F(1) offspring fitness depend on environmental conditions. Our results demonstrated a fitness trade-off between male and female offspring from polyandrous mothers in a competitive environment. The mechanisms and biological significance of this unique phenomenon are discussed.
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The impact of plant and flower age on mating patterns
Marshall, Diane L.; Avritt, Joy J.; Maliakal-Witt, Satya; Medeiros, Juliana S.; Shaner, Marieken G. M.
2010-01-01
Background Over a season, plant condition, amount of ongoing reproduction and biotic and abiotic environmental factors vary. As flowers age, flower condition and amount of pollen donated and received also vary. These internal and external changes are significant for fitness if they result in changes in reproduction and mating. Scope Literature from several fields was reviewed to provide a picture of the changes that occur in plants and flowers that can affect mating over a season. As flowers age, both the entire flower and individual floral whorls show changes in appearance and function. Over a season, changes in mating often appear as alteration in seed production vs. pollen donation. In several species, older, unpollinated flowers are more likely to self. If flowers are receiving pollen, staying open longer may increase the number of mates. In wild radish, for which there is considerable information on seed paternity, older flowers produce fewer seeds and appear to discriminate less among pollen donors. Pollen donor performance can also be linked to maternal plant age. Different pollinators and mates are available across the season. Also in wild radish, maternal plants appear to exert the most control over paternity when they are of intermediate age. Conclusions Although much is known about the characters of plants and flowers that can change over a season, there is less information on the effects of age on mating. Several studies document changes in self-pollination over time, but very few, other than those on wild radish, consider more subtle aspects of differential success of pollen donors over time. PMID:19875519
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Duthie, A Bradley; Reid, Jane M
2016-12-01
While extensive population genetic theory predicts conditions favoring evolution of self-fertilization versus outcrossing, there is no analogous theory that predicts conditions favoring evolution of inbreeding avoidance or inbreeding preference enacted through mate choice given obligate biparental reproduction. Multiple interacting processes complicate the dynamics of alleles underlying such inbreeding strategies, including sexual conflict, distributions of kinship, genetic drift, purging of mutation load, direct costs, and restricted kin discrimination. We incorporated these processes into an individual-based model to predict conditions where selection should increase or decrease frequencies of alleles causing inbreeding avoidance or inbreeding preference when females or males controlled mating. Selection for inbreeding avoidance occurred given strong inbreeding depression when either sex chose mates, while selection for inbreeding preference occurred given very weak inbreeding depression when females chose but never occurred when males chose. Selection for both strategies was constrained by direct costs and restricted kin discrimination. Purging was negligible, but allele frequencies were strongly affected by drift in small populations, while selection for inbreeding avoidance was weak in larger populations because inbreeding risk decreased. Therefore, while selection sometimes favored alleles underlying inbreeding avoidance or preference, evolution of such strategies may be much more restricted and stochastic than is commonly presumed.
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Reproductive Performance of Arabian and Thoroughbred Mares under Subtropical Conditions of Pakistan.
Warriach, H M; Memon, M A; Ahmad, N; Norman, S T; Ghafar, A; Arif, M
2014-07-01
Breeding records of 57 Arabian and 66 Thoroughbred mares were analysed to assess their reproductive performance under the subtropical conditions of Pakistan. The Arabian mares showed significantly higher conception rates (p<0.05) in second mated oestrus and foal heat mated oestrus compared to Thoroughbred mares. However, conception rates for first lifetime mated oestrus were similar in both breeds of mares. Age at first mating (1,301±40 vs 1,500±32 days) was significantly (p<0.05) less in Arabian compared to Thoroughbred mares. Both breeds of mares showed significantly (p<0.05) higher frequencies of oestrous cycles and conception rates during the winter (October to March) compared to summer (June to August) months. Age of mares affected the conception rates, as mares at ages 3 to 7 and 8 to 12 years of ages had significantly higher conception rates (p<0.05) than those ≥18 years old in both breeds. This study demonstrates that i) reproductive performance in Arabians is better than Thoroughbred mares under the subtropical conditions of Pakistan, ii) mares remain cyclic throughout the year and iii) conception rates were higher in mares bred during winter compared to summer months.
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Female rats express a conditioned object preference for receipt of sexual stimulation.
Guterl, Sophie A; McNamara, Tanner A; Klumpp, Gracie C; Meerts, Sarah H
2015-11-01
Female rats alternately approach and avoid the male rat during copulation, potentially reflecting appetitive and aversive aspects of mating, respectively. We developed a novel classical conditioning procedure, conditioned object preference (COP), to test whether female rats show increased approach toward a conditioned stimulus associated directly with receipt of sexual stimulation. During conditioning, one scented object was paired with an appetitive stimulus and a different object plus scent was paired with a control stimulus on a separate day. After conditioning, preference for each object was evaluated with a choice task. Experiment 1 was conducted to verify the procedure. Rats exhibited a significant COP for 1mg/kg amphetamine, indicating that the conditioned object preference procedure is an effective tool for evaluating the rewarding nature of a treatment. In Experiment 2, paced mating to one ejaculation and experimenter-delivered artificial vaginocervical stimulation (aVCS) each induced a COP. The robust COPs for paced mating and aVCS support the notion that female rats experience a reward state during receipt of sexual stimulation. Moreover, the data suggest that any aversive aspects of receipt of sexual stimulation do not overshadow the appetitive effects. Copyright © 2015 Elsevier Inc. All rights reserved.
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Ludwig, Sonja C.; Hemetsberger, Josef; Kotrschal, Kurt; Wascher, Claudia A.F.
2017-01-01
Background Blood parameters such as haematocrit or leucocyte counts are indicators of immune status and health, which can be affected, in a complex way, by exogenous as well as endogenous factors. Additionally, social context is known to be among the most potent stressors in group living individuals, therefore potentially influencing haematological parameters. However, with few exceptions, this potential causal relationship received only moderate scientific attention. Methods In a free-living and individually marked population of the highly social and long-lived Greylag goose, Anser anser, we relate variation in haematocrit (HCT), heterophils to lymphocytes ratio (H/L) and blood leucocyte counts to the following factors: intrinsic (sex, age, raising condition, i.e. goose- or hand-raised), social (pair-bond status, pair-bond duration and parental experience) and environmental (biologically relevant periods, ambient temperature) factors. Blood samples were collected repeatedly from a total of 105 focal birds during three biologically relevant seasons (winter flock, mating season, summer). Results We found significant relationships between haematological parameters and social as well as environmental factors. During the mating season, unpaired individuals had higher HCT compared to paired and family individuals and this pattern reversed in fall. Similarly, H/L ratio was positively related to pair-bond status in a seasonally dependent way, with highest values during mating and successful pairs had higher H/L ratio than unsuccessful ones. Also, absolute number of leucocytes tended to vary depending on raising condition in a seasonally dependent way. Discussion Haematology bears a great potential in ecological and behavioural studies on wild vertebrates. In sum, we found that HTC, H/L ratio and absolute number of leucocytes are modulated by social factors and conclude that they may be considered valid indicators of individual stress load. PMID:28070455
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Hold on: females modulate sperm depletion from storage sites in the fly Drosophila melanogaster.
Bloch Qazi, Margaret C; Hogdal, Leah
2010-09-01
Among many species of insects, females gain fitness benefits by producing numerous offspring. Yet actions related to producing numerous offspring such as mating with multiple males, producing oocytes and placing offspring in sub-optimal environments incur costs. Females can decrease the magnitude of these costs by retaining gametes when suitable oviposition sites are absent. We used the pomace fly, Drosophila melanogaster, to explore how the availability of fresh feeding/oviposition medium influenced female fitness via changes in offspring survivorship and the modulation of gamete release. Availability of fresh medium affected the absolute number and temporal production of offspring. This outcome was attributable to both decreased larval survival under crowded conditions and to female modulation of gamete release. Direct examination of the number of sperm retained among the different female storage organs revealed that females 'hold on' to sperm, retaining more sperm in storage, disproportionately within the spermathecae, when exposed infrequently to fresh medium. Despite this retention, females with lower rates of storage depletion exhibited decreased sperm use efficiency shortly after mating. This study provides direct evidence that females influence the rate of sperm depletion from specific storage sites in a way that can affect both female and male fitness. The possible adaptive significance of selective gamete utilization by female Drosophila includes lowering costs associated with frequent remating and larval overcrowding when oviposition sites are limiting, as well as potentially influencing paternity when females store sperm from multiple males.
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2014-01-01
Background Polyandry is a common mating strategy in animals, increasing female fitness through direct (material) and indirect (genetic) benefits. Most theories about the benefits of polyandry come from studies of terrestrial animals, which have relatively complex mating systems and behaviors; less is known about the potential benefits of polyandry in sessile marine animals, for which potential mates may be scarce and females have less control over pre-copulatory mate choice. Here, we used microsatellite markers to examine multiple paternity in natural aggregations of the Pacific gooseneck barnacle Pollicipes elegans, testing the effect of density on paternity and mate relatedness on male reproductive success. Results We found that multiple paternity was very common (79% of broods), with up to five fathers contributing to a brood, though power was relatively low to detect more than four fathers. Density had a significant and positive linear effect on the number of fathers siring a brood, though this relationship leveled off at high numbers of fathers, which may reflect a lack of power and/or an upper limit to polyandry in this species. Significant skew in male reproductive contribution in multiply-sired broods was observed and we found a positive and significant relationship between the proportion of offspring sired and the genetic similarity between mates, suggesting that genetic compatibility may influence reproductive success in this species. Conclusions To our knowledge, this is the first study to show high levels of multiple paternity in a barnacle, and overall, patterns of paternity in P. elegans appear to be driven primarily by mate availability. Evidence of paternity bias for males with higher relatedness suggests some form of post-copulatory sexual selection is taking place, but more work is needed to determine whether it operates during or post-fertilization. Overall, our results suggest that while polyandry in P. elegans is driven by mate availability, it may also provide a mechanism for females to ensure fertilization by compatible gametes and increase reproductive success in this sessile species. PMID:24739102
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Femininity and masculinity across the menstrual cycle: a relation to mate value.
Hromatko, Ivana; Tadinac, Meri; Vranić, Andrea
2008-01-01
Numerous studies have shown that menstrual cycle related variations in sex hormones influence various cognitive processes. These shifts are considered as the evidence for a hormone-mediated adaptive design underlying human mating motivation. In a series of related studies we have shown that (i) femininity does not vary across the menstrual cycle, whereas masculinity is the most pronounced during the fertile period, (ii) masculinity, but not femininity, predicts shifts in spatial cognition across the menstrual cycle, and (iii) women with different positions on masculinity and femininity dimensions differ in their self-perceived mate value. These results suggest that (i) there might be a hormone mediated psychological mechanism making a woman more assertive and dominant during a short time-window when the conception is likely, (ii) menstrual cycle related shifts in cognitive abilities and mating motivation might have a common hormonal mechanism, and (iii) women's mate value (and indirectly her reproductive success) depends upon both feminine and masculine traits.
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High temperatures disrupt Artemia franciscana mating patterns and impact sexual selection intensity
NASA Astrophysics Data System (ADS)
Santos, Maria R.; Vieira, Natividade; Monteiro, Nuno M.
2018-07-01
Temperature plays a critical role in survival and reproduction, especially in ectotherms. Therefore, it is important to understand the mechanisms influencing life history traits and reproductive behaviours in order to predict climate change impacts on species' occurrence and performance. Here, we used the crustacean Artemia franciscana to investigate the potential impacts of temperature on life history traits, mating patterns and intensity of sexual selection. We reared A. franciscana at three temperatures 20 °C, 25 °C, and 30 °C and measured life history traits such as growth, mortality or development of sexual traits. Our observations confirmed a clear link between life history traits and temperature, with advanced sexual maturity and increased mortality rates following temperature rises. Also, we found that mating is size assortative close to the ideal developmental temperature. Nevertheless, when temperatures deviate from the optimum, mating patterns were altered. Although selection intensity for females remained similar at all tested temperatures, as males preferentially mated with the larger females, size assortative mating disappeared at the highest temperature. Overall, our results highlight the potential for a temperature-dependent disruption of A. franciscana mating patterns. This disruption is especially pronounced under high temperatures as reproduction becomes progressively more random, thus entailing a relaxation of sexual selection intensity.
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Males of the orb-web spider Argiope bruennichi sacrifice themselves to unrelated females
Welke, Klaas W.; Schneider, Jutta M.
2010-01-01
Costs of inbreeding can lead to total reproductive failure and inbreeding avoidance is, therefore, common. In classical sex roles with no paternal care, the selective pressure to avoid inbreeding is mostly on the female, which carries the higher costs. In some orb-web spiders, this situation is very different because females are polyandrous and males are monogynous or at most bigynous. Additionally, females of many entelegyne orb weavers are thought to bias paternity post-copulatorily towards a desired mate. This increases the selective pressure on males to adjust their investment in a mating with regard to the compatibility to a female. Here, we examine whether genetic relatedness influences mating behaviour in the orb-web spider Argiope bruennichi. We mated either a sibling or a non-sibling male to a female in single copulation trials and compared copulation duration, cannibalism rate and female fecundity. Our experiment revealed that males prolonged their copulation duration and were cannibalized more frequently when mating with a non-sibling female. Males mating with a sibling female were more likely to escape cannibalism by copulating briefly, thus presumably increasing their chances of re-mating with a more compatible female. This suggests that males can adaptively adjust their investment relating to the compatibility of a female. PMID:20410027
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The yerba mate intake has a neutral effect on bone: A case-control study in postmenopausal women.
da Veiga, Denise T A; Bringhenti, Raísa; Bolignon, Aline A; Tatsh, Etiane; Moresco, Rafael N; Comim, Fabio V; Premaor, Melissa O
2018-01-01
Nutritional factors have been associated with osteoporosis and fractures. The intake of coffee may increase the risk of fracture whereas the intake of black and green tea is associated with its reduction. Recently, consumption of yerba mate was associated with increased bone mineral density in postmenopausal women. Nonetheless, its influence on fracture is not known. The aim of this study was to evaluate the effect of yerba mate tea intake on fractures, bone markers, calcium homeostasis, and oxidative stress in postmenopausal women. A case-control study was carried out in South Brazil, 46 women with fractures and 49 controls completed the study. There was no significant difference between the frequency of fractures in women who drank mate tea and women who did not (48.3% vs. 48.5%, p = .99). Moreover, there was no significant difference concerning the serum levels of total calcium, phosphorus, PTH, vitamin D, P1NP, and CTX in the subjects with the history of yerba mate use when compared to controls. Higher serum levels of NOx were found in women who drank the yerba mate infusion. In conclusion, the yerba mate intake is not associated with fracture, and it appears to have a neutral effect on the bone metabolism. Copyright © 2017 John Wiley & Sons, Ltd.
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Wright, David J; Brouwer, Lyanne; Mannarelli, Maria-Elena; Burke, Terry; Komdeur, Jan; Richardson, David S
2016-01-01
The prevalence and significance of precopulatory mate choice remains keenly debated. The major histocompatibility complex (MHC) plays a key role in vertebrate adaptive immunity, and variation at the MHC influences individual survival. Although MHC-dependent mate choice has been documented in certain species, many other studies find no such pattern. This may be, at least in part, because in natural systems constraints may reduce the choices available to individuals and prevent full expression of underlying preferences. We used translocations to previously unoccupied islands to experimentally reduce constraints on female social mate choice in the Seychelles warbler ( Acrocephalus sechellensis ), a species in which patterns of MHC-dependent extrapair paternity (EPP), but not social mate choice, have been observed. We find no evidence of MHC-dependent social mate choice in the new populations. Instead, we find that older males and males with more microsatellite heterozygosity are more likely to have successfully paired. Our data cannot resolve whether these patterns in pairing were due to male-male competition or female choice. However, our research does suggest that female Seychelles warblers do not choose social mates using MHC class I to increase fitness. It may also indicate that the MHC-dependent EPP observed in the source population is probably due to mechanisms other than female precopulatory mate choice based on MHC cues.
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Morphological adaptation influences the evolution of a mating signal.
Ballentine, Barbara
2006-09-01
Theory predicts that forces of natural selection can reduce the intensity of sexually selected traits. In this study, I investigate how morphological adaptation to feeding ecology influences a mating signal. In birds, changes in feeding ecology can cause rapid divergence in bill morphology. Because bills are also important for song production, feeding ecology may influence song divergence. During song, birds can rapidly change vocal tract resonance using bill movement, yet are constrained in rate and magnitude of bill movements resulting in a trade-off between trill rate and frequency bandwidth. Male swamp sparrows vary in their ability to produce rapid, broad-band trills and females prefer more physically demanding songs. Populations of swamp sparrows adapted to the feeding ecology of tidal marshes have larger bills than inland populations. Larger bills should increase the constraints of producing rapid, broad-band trills allowing for a test of how changes in feeding ecology affect a feature of song used in mate choice. I found significant differences in acoustic features of song consistent with the hypothesis that coastal males are less able to meet the physical demands of song production because of the constraints of having larger bills. As possible compensation for decreases in song performance, coastal populations exhibit an increase in song complexity. These changes support the current model of how motor constraints influence song production and suggest a mechanism by which feeding ecology can influence signal evolution.
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Cator, Lauren J; Zanti, Zacharo
2016-12-01
Several new mosquito control strategies will involve the release of laboratory reared males which will be required to compete with wild males for mates. Currently, the determinants of male mating success remain unclear. The presence of convergence between male and female harmonic flight tone frequencies during a mating attempt have been found to increase male mating success in the yellow fever mosquito, Aedes aegypti. Size has also been implicated as a factor in male mating success. Here, we investigated the relationships among body size, harmonic convergence signalling, and mating success. We predicted that harmonic convergence would be an important determinant of mating success and that large individuals would be more likely to converge. We used diet to manipulate male and female body size and then measured acoustic interactions during mating attempts between pairs of different body sizes. Additionally, we used playback experiments to measure the direct effect of size on signalling performance. In live pair interactions, harmonic convergence was found to be a significant predictor of copula formation. However, we also found interactions between harmonic convergence behaviour and body size. The probability that a given male successfully formed a copula was a consequence of his size, the size of the female encountered, and whether or not they converged. While convergence appears to be predictive of mating success regardless of size, the positive effect of convergence was modulated by size combinations. In playbacks, adult body size did not affect the probability of harmonic convergence responses. Both body size and harmonic convergence signalling were found to be determinants of male mating success. Our results suggest that in addition to measuring convergence ability of mass release lines that the size distribution of released males may need to be adjusted to complement the size distribution of females. We also found that diet amount alone cannot be used to increase male mating success or convergence probability. A clearer understanding of convergence behaviours, their relationship to mating success, and factors influencing convergence ability would provide the groundwork for improving the mating performance of laboratory reared lines.
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Meunier, J; Kölliker, M
2013-10-01
Although inbreeding is commonly known to depress individual fitness, the severity of inbreeding depression varies considerably across species. Among the factors contributing to this variation, family interactions, life stage and sex of offspring have been proposed, but their joint influence on inbreeding depression remains poorly understood. Here, we demonstrate that these three factors jointly shape inbreeding depression in the European earwig, Forficula auricularia. Using a series of cross-breeding, split-clutch and brood size manipulation experiments conducted over two generations, we first showed that sib mating (leading to inbred offspring) did not influence the reproductive success of earwig parents. Second, the presence of tending mothers and the strength of sibling competition (i.e. brood size) did not influence the expression of inbreeding depression in the inbred offspring. By contrast, our results revealed that inbreeding dramatically depressed the reproductive success of inbred adult male offspring, but only had little effect on the reproductive success of inbred adult female offspring. Overall, this study demonstrates limited effects of family interactions on inbreeding depression in this species and emphasizes the importance of disentangling effects of sib mating early and late during development to better understand the evolution of mating systems and population dynamics. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.
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Beukes, P C; Burke, C R; Levy, G; Tiddy, R M
2010-08-01
An approach to assessing likely impacts of altering reproductive performance on productivity and profitability in pasture-based dairy farms is described. The basis is the development of a whole farm model (WFM) that simulates the entire farm system and holistically links multiple physical performance factors to profitability. The WFM consists of a framework that links a mechanistic cow model, a pasture model, a crop model, management policies and climate. It simulates individual cows and paddocks, and runs on a day time-step. The WFM was upgraded to include reproductive modeling capability using reference tables and empirical equations describing published relationships between cow factors, physiology and mating management. It predicts reproductive status at any time point for individual cows within a modeled herd. The performance of six commercial pasture-based dairy farms was simulated for the period of 12 months beginning 1 June 2005 (05/06 year) to evaluate the accuracy of the model by comparison with actual outcomes. The model predicted most key performance indicators within an acceptable range of error (residual<10% of observed). The evaluated WFM was then used for the six farms to estimate the profitability of changes in farm "set-up" (farm conditions at the start of the farming year on 1 June) and mating management from 05/06 to 06/07 year. Among the six farms simulated, the 4-week calving rate emerged as an important set-up factor influencing profitability, while reproductive performance during natural bull mating was identified as an area with the greatest opportunity for improvement. The WFM presents utility to explore alternative management strategies to predict likely outcomes to proposed changes to a pasture-based farm system. Copyright (c) 2010 Elsevier B.V. All rights reserved.
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Kuiper, Lindsey B; Frohmader, Karla S; Coolen, Lique M
2017-09-01
The use of psychostimulants is often associated with hypersexuality, and psychostimulant users have identified the effects of drug on sexual behavior as a reason for further use. It was previously demonstrated in male rats that methamphetamine (Meth), when administered concurrently with sexual behavior results in impairment of inhibition of sexual behavior in a conditioned sex aversion (CSA) paradigm where mating is paired with illness. This is indicative of maladaptive sex behavior following Meth and sex experience. The present study examined the neural pathways activated during inhibition of sexual behavior in male rats and the effects of concurrent Meth and sexual behavior on neural activity, using ERK phosphorylation (pERK). First, exposure to conditioned aversive stimuli in males trained to inhibit sexual behavior in the CSA paradigm increased pERK expression in medial prefrontal (mPFC), orbitofrontal cortex (OFC) and areas in striatum and amygdala. Second, effects of concurrent Meth and sex experience were tested in males that were exposed to four daily sessions of concurrent Meth (1 mg/kg) or saline and mating and subsequently exposed to CSA one week after last treatment. Meth and mating-treated males showed significant impairment of inhibition of mating, higher pERK expression under baseline conditions, and disrupted pERK induction by exposure to the conditioned aversive stimuli in mPFC and OFC. These alterations of pERK occurred in CaMKII-expressing neurons, suggesting changes in efferent projections of these areas. Altogether, these data show that concurrent Meth and mating experience causes maladapative sexual behavior that is associated with alterations in neural activation in mPFC and OFC.
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NASA Astrophysics Data System (ADS)
Takeshita, Fumio; Murai, Minoru
2016-06-01
In some fiddler crab species, males emit vibrations from their burrows to mate-searching females after they have attracted a female to the burrow entrance using a waving display. Although the vibrations are considered acoustic signals to induce mating, it has not been demonstrated whether the vibrations attract the females into the burrow and, consequently, influence females' mating decisions. We investigated the structures and patterns of the vibrations using a dummy female and demonstrated experimentally a female preference for male vibrations in Uca lactea in the field. The acoustic signals consisted of repetitions of pulses. The dominant frequency of the pulses decreased with male carapace width. The pulse length decreased slightly with an increasing number of vibrational repetitions, and the pulse interval increased with increasing repetitions. These factors imply that the vibrations convey information on male characteristics, such as body size and stamina. In the experiment on female mate choice, the females significantly preferred males with higher pulse repetition rates when they were positioned at the entrance of the burrow, indicating that the females use the male vibrational signals to decide whether to enter the burrow. However, females showed no preference for the vibrations once they were inside a burrow, i.e., whether they decided to copulate, suggesting that the vibrations do not independently affect a female's final decision of mate choice. The vibrations inside the burrow might influence a female's decision by interaction with other male traits such as the burrow structure.
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Genetic caste polymorphism and the evolution of polyandry in Atta leaf-cutting ants
NASA Astrophysics Data System (ADS)
Evison, Sophie Elizabeth Frances; Hughes, William O. H.
2011-08-01
Multiple mating by females with different males (polyandry) is difficult to explain in many taxa because it carries significant costs to females, yet benefits are often hard to identify. Polyandry is a derived trait in social insects, the evolutionary origins of which remain unclear. One of several leading hypotheses for its evolution is that it improves division of labour by increasing intra-colonial genetic diversity. Division of labour is a key player in the ecological success of social insects, and in many successful species of ants is based on morphologically distinct castes of workers, each with their own task specialisations. Atta leaf-cutting ants exhibit one of the most extreme and complicated forms of morphologically specialised worker castes and have been reported to be polyandrous but with relatively low mating frequencies (~2.5 on average). Here, we show for the first time that there is a significant genetic influence on worker size in Atta colombica leaf-cutting ants. We also provide the first estimate of the mating frequency of Atta cephalotes (four matings) and, by analysing much higher within-colony sample sizes, find that Atta are more polyandrous than previously thought (approximately six to seven matings). The results show that high polyandry and a genetic influence on worker caste are present in both genera of leaf-cutting ants and add weight to the hypothesis that division of labour is a potential driver of the evolution of polyandry in this clade of ants.
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Sardell, Rebecca J; Kempenaers, Bart; Duval, Emily H
2014-02-01
Indirect benefits of mate choice result from increased offspring genetic quality and may be important drivers of female behaviour. 'Good-genes-for-viability' models predict that females prefer mates of high additive genetic value, such that offspring survival should correlate with male attractiveness. Mate choice may also vary with genetic diversity (e.g. heterozygosity) or compatibility (e.g. relatedness), where the female's genotype influences choice. The relative importance of these nonexclusive hypotheses remains unclear. Leks offer an excellent opportunity to test their predictions, because lekking males provide no material benefits and choice is relatively unconstrained by social limitations. Using 12 years of data on lekking lance-tailed manakins, Chiroxiphia lanceolata, we tested whether offspring survival correlated with patterns of mate choice. Offspring recruitment weakly increased with father attractiveness (measured as reproductive success, RS), suggesting attractive males provide, if anything, only minor benefits via offspring viability. Both male RS and offspring survival until fledging increased with male heterozygosity. However, despite parent-offspring correlation in heterozygosity, offspring survival was unrelated to its own or maternal heterozygosity or to parental relatedness, suggesting survival was not enhanced by heterozygosity per se. Instead, offspring survival benefits may reflect inheritance of specific alleles or nongenetic effects. Although inbreeding depression in male RS should select for inbreeding avoidance, mates were not less related than expected under random mating. Although mate heterozygosity and relatedness were correlated, selection on mate choice for heterozygosity appeared stronger than that for relatedness and may be the primary mechanism maintaining genetic variation in this system despite directional sexual selection. © 2014 John Wiley & Sons Ltd.
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Goes, Marcio Douglas; Reis Goes, Elenice Souza Dos; Ribeiro, Ricardo Pereira; Lopera-Barrero, Nelson Maurício; Castro, Pedro Luiz de; Bignotto, Thaís Souto; Bombardelli, Robie Allan
2017-01-15
This study evaluated the reproductive parameters and genetic variability of offspring of Rhamdia quelen from mating by natural spawning and by controlled fertilization with fresh and cryopreserved semen. After hormonal manipulation, three R quelen pairs were used for natural spawning in high-flow tanks, three pairs were used for mating with fresh semen, and another three pairs were used with cryopreserved semen. Matings were performed in triplicate. For matings with fresh and cryopreserved semen, semen from each male was used to individually fertilize oocytes from each female. Pools of semen and oocytes were made, and aliquots of these gametes were taken for fertilization. No differences (P > 0.05) were detected for absolute or relative fecundity, fertilization rate, or egg hatching rate. The use of fresh semen led to a higher (P < 0.01) percentage of normal larvae. The use of fresh semen in pooled mating resulted in a greater effective number of alleles and a higher expected heterozygosity. Offspring from natural spawning presented higher observed heterozygosity and a lower inbreeding coefficient. The highest inbreeding coefficient was found in offspring from individual matings using fresh semen. Regarding paternal contributions, a single male dominated in matings with fresh semen, whereas two males dominated in natural spawning and matings using cryopreserved semen. The use of gamete pools for mating and natural spawning resulted in higher genetic variability of offspring, and mating using cryopreserved semen found no effects on genetic variability of offspring but did reduce the percentage of normal larvae. Other reproductive parameters were not influenced by spawning strategies. Copyright © 2016. Published by Elsevier Inc.
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No evidence of an MHC-based female mating preference in great reed warblers.
Westerdahl, Helena
2004-08-01
Female mate-choice based on genetic compatibility is an area of growing interest. The major histocompatibility complex (MHC) genes are likely candidates for such mate-choice since these highly polymorphic genes may both increase offspring viability and also provide direct cues for mate-choice. In great reed warblers, females actively choose a breeding partner out of a handful of males that they visit and evaluate; thus, female preference for compatible or heterozygous MHC genes could have evolved. Here, I investigate whether great reed warbler females preferentially mate with males with dissimilar MHC class I alleles or with males that are heterozygous at MHC class I. Despite favourable conditions, a thorough screening method and a large sample size, there was no evidence of an MHC-based female mating preference based on either genetic compatibility or heterozygosity in this population. Power analyses of the data sets revealed that relatively small differences (15% and 8%, respectively) between true and random pairs should have been detected. Copyright 2004 Blackwell Publishing Ltd
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Fluctuating environments, sexual selection and the evolution of flexible mate choice in birds.
Botero, Carlos A; Rubenstein, Dustin R
2012-01-01
Environmentally-induced fluctuation in the form and strength of natural selection can drive the evolution of morphology, physiology, and behavior. Here we test the idea that fluctuating climatic conditions may also influence the process of sexual selection by inducing unexpected reversals in the relative quality or sexual attractiveness of potential breeding partners. Although this phenomenon, known as 'ecological cross-over', has been documented in a variety of species, it remains unclear the extent to which it has driven the evolution of major interspecific differences in reproductive behavior. We show that after controlling for potentially influential life history and demographic variables, there are significant positive associations between the variability and predictability of annual climatic cycles and the prevalence of infidelity and divorce within populations of a taxonomically diverse array of socially monogamous birds. Our results are consistent with the hypothesis that environmental factors have shaped the evolution of reproductive flexibility and suggest that in the absence of severe time constraints, secondary mate choice behaviors can help prevent, correct, or minimize the negative consequences of ecological cross-overs. Our findings also illustrate how a basic evolutionary process like sexual selection is susceptible to the increasing variability and unpredictability of climatic conditions that is resulting from climate change.
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ERIC Educational Resources Information Center
Brosnan, Mark; Walker, Ian
2009-01-01
Of particular interest to studying the etiology of Autistic Spectrum Disorders (ASDs) is the potential for multiple risk factors to combine through non-random mechanisms--assortative mating. Both genetic influences and a high-testosterone prenatal environment have been implicated in the etiology of ASDs, and given that waist-hip ratio (WHR) is…
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Bruce E. Byers; Michael E. Akresh; David I. King
2015-01-01
In songbirds, female mate choice may be influenced by how well a male performs his songs. Performing songs well may be especially difficult if it requires maximizingmultiple aspects of performance simultaneously.We therefore hypothesized that, in a population of prairie warblers, the males most attractive to females would be those with superior performance in more than...
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Evolutionary Trade-Off between Secondary Sexual Traits and Ejaculates.
Simmons, Leigh W; Lüpold, Stefan; Fitzpatrick, John L
2017-12-01
Recent theoretical models predict that the evolutionary diversification of the weapons and ornaments of pre-mating sexual selection should be influenced by trade-offs with male expenditure on ejaculates. However, the patterns of association between secondary sexual traits and ejaculate expenditure are frequently inconsistent in their support of this prediction. We show why consideration of additional life-history, ecological, and mating-system variables is crucial for the interpretation of associations between secondary sexual traits and ejaculate production. Incorporation of these 'missing variables' provides evidence that interactions between pre- and post-mating sexual selection can underlie broad patterns of diversification in male weapons and ornaments. We call for more experimental and genetic approaches to uncover trade-offs, as well as for studies that consider the costs of mate-searching. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Linhares, Bruno; Weber, Caroline Trevisan; Foletto, Edson Luiz; Paz, Diego Silva; Mazutti, Marcio A; Collazzo, Gabriela Carvalho
2013-01-01
Activated carbon prepared from yerba mate (Ilex paraguariensis) was used as adsorbent for the removal of tannery dye from aqueous solution. The activated carbon was characterized, and it showed a mesoporous texture, with surface area of 537.4 m2 g(-1). The initial dye concentration, contact time and pH influenced the adsorption capacity. The equilibrium data were in good agreement with both Langmuir and Freundlich isotherms. The adsorption kinetics of the tannery dye on activated carbon prepared from yerba mate followed a pseudo-second-order model. The adsorption process was found to be controlled by both external mass-transfer and intraparticle diffusion, but the external diffusion was the dominating process. This work highlights the potential application of activated carbon produced from yerba mate in the field of adsorption.
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Duménil, Claire; Woud, David; Pinto, Francesco; Alkema, Jeroen T; Jansen, Ilse; Van Der Geest, Anne M; Roessingh, Sanne; Billeter, Jean-Christophe
2016-03-01
Individuals can make choices based on information learned from others, a phenomenon called social learning. How observers differentiate between which individual they should or should not learn from is, however, poorly understood. Here, we showed that Drosophila melanogaster females can influence the choice of egg-laying site of other females through pheromonal marking. Mated females mark territories of high quality food by ejecting surplus male sperm containing the aggregation pheromone cis-11-vaccenyl acetate (cVA) and, in addition, deposit several sex- and species-specific cuticular hydrocarbon (CHC) pheromones. These pheromonal cues affect the choices of other females, which respond by preferentially laying eggs on the marked food. This system benefits both senders and responders, as communal egg laying increases offspring survival. Virgin females, however, do not elicit a change in the egg-laying decision of mated females, even when food has been supplemented with ejected sperm from mated females, thus indicating the necessity for additional cues. Genetic ablation of either a female's CHC pheromones or those of their mate results in loss of ability of mated females to attract other females. We conclude that mated females use a pheromonal marking system, comprising cVA acquired from male ejaculate with sex- and species-specific CHCs produced by both mates, to indicate egg-laying sites. This system ensures information reliability because mated, but not virgin, females have both the ability to generate the pheromone blend that attracts other flies to those sites and a direct interest in egg-laying site quality.
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Kinship and mate choice in a historic eastern Blue Ridge community, Madison County, Virginia.
Frankenberg, S R
1990-12-01
Potential mates analysis is difficult to apply to small historic populations that lack clear boundaries or regular vital event registration. Here I analyze the actual mate pool as an alternative way to identify causes of nonrandom mating when unmarried members are unknown. Factors influencing mate choice within a historic eastern Blue Ridge community in Madison County, Virginia, are examined for four marriage cohorts: 1850-1879, 1880-1899, 1900-1919, and 1920-1939. These factors include nuclear kin avoidance, preferred age differences between mates, and preferences for more distant kin. A simulation is used to recombine members of the cohort-specific pools of married individuals to generate the probabilities of various types of kin marriages. The pedigree and vital statistics data are derived from first-time marriage licenses filled by community members in Madison County from 1794 to 1939. The numbers of marriages examined for each cohort are 88, 120, 132, and 132, respectively; the mate pools constructed from the samples are viewed from the female perspective. The results generated by simulation on the actual mate pools consist of mean kinship coefficients, numbers of marriages between "allowed" kin types, and probabilities of these values when marriage is random with respect to kinship. The results indicate significantly high levels of inbreeding in all four marriage cohorts, primarily because of high levels of first-cousin marriages in the first three cohorts and of first-cousin once-removed marriages in the 1920 cohort. The observed mating patterns are discussed in terms of the social history of the Blue Ridge community and restrictions of the data.
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Johnsen, Arild; Pauliny, Angela; Lifjeld, Jan T; Blomqvist, Donald
2017-01-01
Telomere length is related to aging in many eukaryotes and the rate of telomere attrition has been suggested to reflect individual genetic quality. Telomere length could thus have implications for mate choice. We investigated telomere length variation in bluethroat Luscinia svecica families with mixed paternity, including social parents, extra-pair fathers and nestlings, testing whether telomere length is associated with social and/or extra-pair mate choice through assortative mating or selection of mates with relatively long telomeres. In adults, relative telomere length (rTL) did not differ between the sexes, nor between two age categories. In chicks, however, rTL decreased with body mass at sampling (an index of nestling age). We found a positive correlation between the rTL of social mates, suggesting assortative mating with respect to telomere length or a correlative thereof. However, extra-pair males did not differ from social mates in rTL, and accordingly there was also no difference between within- and extra-pair young (i.e. half-siblings) when controlling for the effect of mass. We found no relationships between telomere length, age and fitness-related traits in adults, but an intriguing year-difference in telomere length in both sexes. In conclusion, we found no support for the idea that females choose extra-pair males based on their telomere length, but social mate choice seems to be influenced by rTL, possibly through its co-variation with aspects reflecting individual quality, like early arrival at the breeding grounds.
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Aribi, N; Oulhaci, M C; Kilani-Morakchi, S; Sandoz, J C; Kaiser, L; Denis, B; Joly, D
2017-11-01
Azadirachtin, a neem compound (Azadirachta indica) with medical and anti-insect properties, is one the most successful botanical pesticides in agricultural use. However, its controversial impact on non-targeted species and its mechanism of action need to be clarified. In addition, Azadirachtin impact on pre- and post-mating traits remains largely undocumented. The current study examined the effects of Azadirachtin on Drosophila melanogaster as a non-target and model species. Azadirachtin was applied topically at its LD 50 (0.63μg) on the day of adult emergence and its effect was evaluated on several traits of reproductive behavior: mate choice, male activity, female sexual receptivity, sperm storage and female sterility. In choice and no choice conditions, only male treatment reduced mating probability. Female treatment impaired mating probability only when males had the choice. Males' mating ability may have been impaired by an effect of the treatment on their mobility. Such an effect was observed in the actimeter, which revealed that treated males were less active than untreated ones, and this effect persisted over 8days. Azadirachtin treatment had, however, no effect on the nycthemeral rhythm of those males. Even when mating occurred, Azadirachtin treatment impaired post-mating responses especially when females or both sexes were treated: remating probability increases and female fertility (presence of larvae) decreases. No impairment was observed on the efficiency of mating, evaluated by the presence of sperm in the spermatheca or the ventral receptacle. Male treatment only had no significant effect on these post-mating responses. These findings provide clear evidence that Azadirachtin alters the reproductive behavior of both sexes in D. melanogaster via mating and post-mating processes. Copyright © 2017 Elsevier Inc. All rights reserved.
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The measure and significance of Bateman's principles
Collet, Julie M.; Dean, Rebecca F.; Worley, Kirsty; Richardson, David S.; Pizzari, Tommaso
2014-01-01
Bateman's principles explain sex roles and sexual dimorphism through sex-specific variance in mating success, reproductive success and their relationships within sexes (Bateman gradients). Empirical tests of these principles, however, have come under intense scrutiny. Here, we experimentally show that in replicate groups of red junglefowl, Gallus gallus, mating and reproductive successes were more variable in males than in females, resulting in a steeper male Bateman gradient, consistent with Bateman's principles. However, we use novel quantitative techniques to reveal that current methods typically overestimate Bateman's principles because they (i) infer mating success indirectly from offspring parentage, and thus miss matings that fail to result in fertilization, and (ii) measure Bateman gradients through the univariate regression of reproductive over mating success, without considering the substantial influence of other components of male reproductive success, namely female fecundity and paternity share. We also find a significant female Bateman gradient but show that this likely emerges as spurious consequences of male preference for fecund females, emphasizing the need for experimental approaches to establish the causal relationship between reproductive and mating success. While providing qualitative support for Bateman's principles, our study demonstrates how current approaches can generate a misleading view of sex differences and roles. PMID:24648220
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Jin, Zheng; Shiomura, Kimihiro; Jiang, Lizhu
2015-02-01
Love, sex, and money are the most direct cues involved in the fundamental forms of mate preferences. These fundamental forms are not mutually exclusive but are interrelated. As a result, humans base their mate choices on multiple cues. In this study, 62 undergraduate women (M age = 20.4 yr., SD = 1.4) from China and Japan served as the participants. They performed a variation of the semantic priming task, in which they were instructed to decide by means of a key-press whether the target was human or non-human. The primes were images that portrayed potent evolutionary factors for mate preference (i.e., love, sex, and money), and the manipulation was based on whether the prime and target matched regarding gender, independent of the target decision task (human vs non-human). Participants gave faster responses to male targets than to female targets under priming. The results generally supported the evolutionary premises that assume mate preference is determined by fundamental forms of providing emotional (love), material (money), and fertility support (sex). The money priming effect was stronger in the Chinese women than in the Japanese women, suggesting that social context may influence mate preferences.
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Munhenga, Givemore; Brooke, Basil D; Gilles, Jeremie R L; Slabbert, Kobus; Kemp, Alan; Dandalo, Leonard C; Wood, Oliver R; Lobb, Leanne N; Govender, Danny; Renke, Marius; Koekemoer, Lizette L
2016-03-02
Anopheles arabiensis Patton is primarily responsible for malaria transmission in South Africa after successful suppression of other major vector species using indoor spraying of residual insecticides. Control of An. arabiensis using current insecticide based approaches is proving difficult owing to the development of insecticide resistance, and variable feeding and resting behaviours. The use of the sterile insect technique as an area-wide integrated pest management system to supplement the control of An. arabiensis was proposed for South Africa and is currently under investigation. The success of this technique is dependent on the ability of laboratory-reared sterile males to compete with wild males for mates. As part of the research and development of the SIT technique for use against An. arabiensis in South Africa, radio-sensitivity and mating competitiveness of a local An. arabiensis sexing strain were assessed. The optimal irradiation dose inducing male sterility without compromising mating vigour was tested using Cobalt 60 irradiation doses ranging from 70-100 Gy. Relative mating competitiveness of sterile laboratory-reared males (GAMA strain) compared to fertile wild-type males (AMAL strain) for virgin wild-type females (AMAL) was investigated under laboratory and semi-field conditions using large outdoor cages. Three different sterile male to fertile male to wild-type female ratios were evaluated [1:1:1, 5:1:1 and 10:1:1 (sterile males: fertile, wild-type males: fertile, wild-type females)]. Irradiation at the doses tested did not affect adult emergence but had a moderate effect on adult survivorship and mating vigour. A dose of 75 Gy was selected for the competitiveness assays. Mating competitiveness experiments showed that irradiated GAMA male mosquitoes are a third as competitive as their fertile AMAL counterparts under semi-field conditions. However, they were not as competitive under laboratory conditions. An inundative ratio of 10:1 induced the highest sterility in the representative wild-type population, with potential to effectively suppress reproduction. Laboratory-reared and sterilised GAMA male An. arabiensis at a release ratio of 3:1 (3 sterile males to 1 wild, fertile male) can successfully compete for insemination of wild-type females. These results will be used to inform subsequent small-scale pilot field releases in South Africa.
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When Love Is in the Air: Understanding Why Dogs Tend to Mate when It Rains.
Sen Majumder, Sreejani; Bhadra, Anindita
2015-01-01
Seasonality of reproduction is observed in many species of organisms, across taxa, and is influenced by both biotic and abiotic factors. While such seasonality is easy to understand in temperate species exposed to extreme climates, it is more difficult to explain in the tropics. In many tropical species offspring are born during the season of high precipitation, which also coincides with high resource availability. Interestingly, in India, free-ranging dogs seem to mate, and not whelp, when it rains--an observation that cannot be explained by the resource abundance hypothesis. We carried out an extensive study to identify the mating seasons of free-ranging dogs, and observed a strong correlation between both the incidence and frequency of mating related behaviours of dogs, and precipitation levels. There are two clear mating seasons, of which the primary mating season coincides with the monsoon (rainy season) and the secondary mating season coincides with the nor'westerlies in this part of India. We speculate that this strong correlation is an effect of chemistry, rather than biology. While male dogs can mate round the year, females come into estrous seasonally. In the urban environment, dogs are exposed to a lot of olfactory noise, which can dilute the signal present in sex pheromones of the females in heat. A shower leads to increased humidity and reduced temperature of the air, leading to intensification of pheromone signals that trigger a sexual response in the dogs.
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Brooks, R; Endler, J A
2001-08-01
Variation among females in mate choice may influence evolution by sexual selection. The genetic basis of this variation is of interest because the elaboration of mating preferences requires additive genetic variation in these traits. Here we measure the repeatability and heritability of two components of female choosiness (responsiveness and discrimination) and of female preference functions for the multiple ornaments borne by male guppies (Poecilia reticulata). We show that there is significant repeatable variation in both components of choosiness and in some preference functions but not in others. There appear to be several male ornaments that females find uniformly attractive and others for which females differ in preference. One consequence is that there is no universally attractive male phenotype. Only responsiveness shows significant additive genetic variation. Variation in responsiveness appears to mask variation in discrimination and some preference functions and may be the most biologically relevant source of phenotypic and genetic variation in mate-choice behavior. To test the potential evolutionary importance of the phenotypic variation in mate choice that we report, we estimated the opportunity for and the intensity of sexual selection under models of mate choice that excluded and that incorporated individual female variation. We then compared these estimates with estimates based on measured mating success. Incorporating individual variation in mate choice generally did not predict the outcome of sexual selection any better than models that ignored such variation.
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Israeli, Moshe; Kristt, Don; Nardi, Yuval; Klein, Tirza
2014-05-01
Previous studies support a role for MHC on mating preference, yet it remains unsettled as to whether mating occurs preferentially between individuals sharing human leukocyte antigen (HLA) determinants or not. Investigating sex-mate preferences in the contemporary Israeli population is of further curiosity being a population with distinct genetic characteristics, where multifaceted cultural considerations influence mate selection. Pairs of male-female sex partners were evaluated in three groups. Two groups represented unmarried (n = 1002) or married (n = 308) couples and a control group of fictitious male-female couples. HLA and short-tandem-repeat (STR) genetic identification markers were assessed for the frequency of shared antigens and alleles. Human leukocyte antigen results showed that Class I and/ or Class II single antigen as well as double antigen sharing was more common in sex partners than in control group couples (P < 0.001). Married versus unmarried pairs were not distinguishable. In contrast, STR-DNA markers failed to differentiate between sex-mates and controls (P = 0.78). Sex partnerships shared HLA determinants more frequently than randomly constituted male-female pairs. The observed phenomenon does not reflect a syngenetic background between sex-mates as STR markers were not selectively shared. Thus, sex-mate selection in man may contravene the evolutionary pressure for genetic diversity in regard to HLA. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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Mating induces production of MMP2 in the llama oviduct: Analysis of MMP2 effect on semen.
Zampini, Renato; Sari, Luciana M; Argañaraz, Martin E; Fumuso, Fernanda G; Barraza, Daniela E; Carretero, María I; Apichela, Silvana A
2018-05-01
Ovulation of South American Camelids is induced by mating. After copulation, sperm are stored into the oviduct to be released near ovulation time. To study whether copulation induces matrix metalloproteinase-2 (MMP2) secretion in the oviduct, the occurrence of MMP2 in oviductal tissue and oviductal fluid (OF) from 24 h post-mated was compared with non-mated llama females. There was an incremental increase of MMP2 in the oviductal epithelial cells, and MMP2 activity in OF after copulation. Additionally, MMP2 activator (MMP14), inducer (EMMPRIN) and inhibitor (TIMP2) were present in the oviductal epithelial cells of both non-mated and post-mated females. A post-mating segment-specific regulation occurred because relative abundance of TIMP2 mRNA was greater in the utero tubal-junction which was accompanied with a reduced amount of MMP14 in the ampulla in comparison with the non-mated females. To examine the effect of MMP2 on semen liquefaction and sperm physiology, the effects of addition of recombinant human MMP2 was evaluated. The MMP2 had no effect on semen thread formation and seminal plasma protein profile. Sperm viability and plasma membrane function were not influenced by the enzyme treatment either. In summary, in llamas the oviductal microenvironment changes in response to stimuli induced by copulation, increasing the production and secretion of MMP2. Copyright © 2018 Elsevier B.V. All rights reserved.
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Chou, Ranna; Hara, Anna; Du, DongDong; Shimizu, Namiko; Sakuyama, Hiroe; Uehara, Yoshio
2014-01-01
We investigated the influence of maternal salt restriction during mating or gestation on birth rate and offspring growth in Dahl salt-sensitive rats (DS). DS were divided into 5 groups: DS fed a low-salt (0.3% NaCl, w/w) (DS-low) or high-salt (4% NaCl, w/w) diet (DS-high) during mating and DS-high or DS-low during gestation, and DS fed regular chow (0.75% NaCl, w/w) (DS-regular) throughout mating and gestation. During the unspecified periods, the rats were given regular chow. DS-low during mating delivered fewer infants than high-salt mothers (P < 0.05). The birth rate on regular chow was 87%. Six out of 11 DS-low rats during pregnancy produced pups while the rats fed a high-salt diet all delivered pups (P < 0.025). The pup survival rate was 67% for high-salt mothers during mating and 54% for mothers on a low-salt diet. The pup survival rate was 95% for mothers on a high-salt diet during pregnancy and 64% for mothers on a low-salt diet (P < 0.0001). Seven out of 8 DS-regular rats during mating delivered 59 neonates. However, 66% of the neonates survived. A low-salt diet during mating or pregnancy lowers birth rate and the neonates from low-salt mothers during pregnancy were more likely to die than those from high-salt mothers.
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The evolution of mate choice: a dialogue between theory and experiment.
Roff, Derek A
2015-12-01
Research on the evolution of mate choice has followed three avenues of investigation: (1) theoretical models of the evolution of preference and the preferred trait; (2) proposed models of mate choice; and (3) experiments and observations on mate choice, both in the laboratory and with free-ranging animals. However, there has been relatively little dialogue among these three areas. Most attempts to account for observations of mate choice using theoretical mate-choice models have focused only upon a subset of particular models and have generally failed to consider the difference between probabilistic and deterministic models. In this review, I outline the underlying reasoning of the commonly cited mate-choice models and review the conclusions of the empirical investigations. I present a brief outline of how one might go about testing these models. It remains uncertain if, in general, mate-choice models can be realistically analyzed. Although it is clear that females frequently discriminate among males, data also suggest that females may typically have a very limited number of males from which to choose. The extent to which female choice under natural conditions is relatively random because of limited opportunities remains an open question for the majority of species. © 2015 New York Academy of Sciences.
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The evolution of postpairing male mate choice.
Lyu, Nan; Servedio, Maria R; Lloyd, Huw; Sun, Yue-Hua
2017-06-01
An increasing number of empirical studies in animals have demonstrated male mate choice. However, little is known about the evolution of postpairing male choice, specifically which occurs by differential allocation of male parental care in response to female signals. We use a population genetic model to examine whether such postpairing male mate choice can evolve when males face a trade-off between parental care and extra-pair copulations (EPCs). Specifically, we assume that males allocate more effort to providing parental care when mated to preferred (signaling) females, but they are then unable to allocate additional effort to seek EPCs. We find that both male preference and female signaling can evolve in this situation, under certain conditions. First, this evolution requires a relatively large difference in parental investment between males mated to preferred versus nonpreferred females. Second, whether male choice and female signaling alleles become fixed in a population versus cycle in their frequencies depends on the additional fecundity benefits from EPCs that are gained by choosy males. Third, less costly female signals enable both signaling and choice alleles to evolve under more relaxed conditions. Our results also provide a new insight into the evolution of sexual conflict over parental care. © 2017 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.
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Hinton, Joseph W.; Gittleman, John L.; van Manen, Frank T.; Chamberlain, Michael J.
2018-01-01
Anthropogenic hybridization of historically isolated taxa has become a primary conservation challenge for many imperiled species. Indeed, hybridization between red wolves (Canis rufus) and coyotes (Canis latrans) poses a significant challenge to red wolf recovery. We considered seven hypotheses to assess factors influencing hybridization between red wolves and coyotes via pair‐bonding between the two species. Because long‐term monogamy and defense of all‐purpose territories are core characteristics of both species, mate choice has long‐term consequences. Therefore, red wolves may choose similar‐sized mates to acquire partners that behave similarly to themselves in the use of space and diet. We observed multiple factors influencing breeding pair formation by red wolves and found that most wolves paired with similar‐sized conspecifics and wolves that formed congeneric pairs with nonwolves (coyotes and hybrids) were mostly female wolves, the smaller of the two sexes. Additionally, we observed that lower red wolf abundance relative to nonwolves and the absence of helpers increased the probability that wolves consorted with nonwolves. However, successful pairings between red wolves and nonwolves were associated with wolves that maintained small home ranges. Behaviors associated with territoriality are energetically demanding and behaviors (e.g., aggressive interactions, foraging, and space use) involved in maintaining territories are influenced by body size. Consequently, we propose the hypothesis that size disparities between consorting red wolves and coyotes influence positive assortative mating and may represent a reproductive barrier between the two species. We offer that it may be possible to maintain wild populations of red wolves in the presence of coyotes if management strategies increase red wolf abundance on the landscape by mitigating key threats, such as human‐caused mortality and hybridization with coyotes. Increasing red wolf abundance would likely restore selection pressures that increase mean body and home‐range sizes of red wolves and decrease hybridization rates via reduced occurrence of congeneric pairs.
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Social and behavioral barriers to pathogen transmission in wild animal populations
DOE Office of Scientific and Technical Information (OSTI.GOV)
Loehle, C.S.
Disease and pathogens have been studied as regulators of animal populations but not really as selective forces. The authors propose that pathogens can be major selective forces influencing social behaviors when these are successful at reducing disease transmission. The behaviors whose evolution could have been influenced by pathogen effects include group size, group isolation, mixed species flocking, migration, seasonal sociality, social avoidance, and dominance behaviors. Mate choice, mating system, and sexual selection are put in a new light when examined in terms of disease transmission. It is concluded that pathogen avoidance is a more powerful selective force than has heretoforemore » been recognized.« less
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Krupp, Joshua J.; Billeter, Jean-Christophe; Wong, Amy; Choi, Charles; Nitabach, Michael N.; Levine, Joel D.
2014-01-01
Summary Social cues contribute to the circadian entrainment of physiological and behavioral rhythms. These cues supplement the influence of daily and seasonal cycles in light and temperature. In Drosophila, the social environment modulates circadian mechanisms that regulate sex pheromone production and mating behavior. Here we demonstrate that a neuroendocrine pathway, defined by the neuropeptide Pigment-Dispersing Factor (PDF), couples the central nervous system (CNS) to the physiological output of peripheral clock cells that produce pheromones, the oenocytes. PDF signaling from the CNS modulates the phase of the oenocyte clock. Despite its requirement for sustaining free-running locomoter activity rhythms, PDF is not necessary to sustain molecular rhythms in the oenocytes. Interestingly, disruption of the PDF signaling pathway reduces male sex pheromones and results in sex-specific differences in mating behavior. Our findings highlight the role of neuropeptide signaling and the circadian system in synchronizing the physiological and behavioral processes which govern social interactions. PMID:23849197
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Pest persistence and eradication conditions in a deterministic model for sterile insect release.
Gordillo, Luis F
2015-01-01
The release of sterile insects is an environment friendly pest control method used in integrated pest management programmes. Difference or differential equations based on Knipling's model often provide satisfactory qualitative descriptions of pest populations subject to sterile release at relatively high densities with large mating encounter rates, but fail otherwise. In this paper, I derive and explore numerically deterministic population models that include sterile release together with scarce mating encounters in the particular case of species with long lifespan and multiple matings. The differential equations account separately the effects of mating failure due to sterile male release and the frequency of mating encounters. When insects spatial spread is incorporated through diffusion terms, computations reveal the possibility of steady pest persistence in finite size patches. In the presence of density dependence regulation, it is observed that sterile release might contribute to induce sudden suppression of the pest population.
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True polyandry and pseudopolyandry: why does a monandrous fly remate?
Fisher, David N; Doff, Rowan J; Price, Tom A R
2013-07-25
The rate of female remating can have important impacts on a species, from affecting conflict and cooperation within families, to population viability and gene flow. However, determining the level of polyandry in a species can be difficult, with information on the mating system of many species being based on a single experiment, or completely absent. Here we investigate the mating system of the fruit fly Drosophila subobscura. Reports from England, Spain and Canada suggest D. subobscura is entirely monandrous, with no females remating. However, work in Greece suggests that 23% of females remate. We examine the willingness of female D. subobscura to remate in the laboratory in a range of conditions, using flies from both Greece and England. We make a distinction between pseudopolyandry, where a female remates after an ineffective first mating that is incapable of fertilising her eggs, and true polyandry, where a female remates even though she has received suitable sperm from a previous mating. We find a low rate of true polyandry by females (4%), with no difference between populations. The rate of true polyandry is affected by temperature, but not starvation. Pseudopolyandry is three times as common as true polyandry, and most females showing pseudopolyandry mated at their first opportunity after their first failed mating. However, despite the lack of differences in polyandry between the populations, we do find differences in the way males respond to exposure to other males prior to mating. In line with previous work, English flies responded to one or more rivals by increasing their copulation duration, a response previously thought to be driven by sperm competition. Greek males only show increased copulation duration when exposed to four or more rival males. This suggests that the response to rivals in D. subobscura is not related to sperm competition, because sperm competition is rare, and there is no correlation of response to rivals and mating system across the populations. These results illustrate the difficulties in determining the mating system of a species, even one that is well known and an excellent laboratory species, with results being highly dependent on the conditions used to assay the behaviour, and the population used.
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Rodríguez, Rafael L; Al-Wathiqui, Nooria
2011-07-01
Theory predicts that selection acting across environments should erode genetic variation in reaction norms; i.e., selection should weaken genotype × environment interaction (G × E). In spite of this expectation, G × E is often detected in fitness-related traits. It thus appears that G × E is at least sometimes sustained under selection, a possibility that highlights the need for theory that can account for variation in the presence and strength of G × E. We tested the hypothesis that trait differences in developmental architecture contribute to variation in the expression of G × E. Specifically, we assessed the influence of canalization (robustness to genetic or environmental perturbations) and condition-dependence (association between trait expression and prior resource acquisition or vital cellular processes). We compared G × E across three trait types expected to differ in canalization and condition-dependence: mating signals, body size-related traits, and genitalia. Because genitalia are expected to show the least condition-dependence and the most canalization, they should express weaker G × E than the other trait types. Our study species was a member of the Enchenopa binotata species complex of treehoppers. We found significant G × E in most traits; G × E was strongest in signals and body traits, and weakest in genitalia. These results support the hypothesis that trait differences in developmental architecture (canalization and condition-dependence) contribute to variation in the expression of G × E. We discuss implications for the dynamics of sexual selection on different trait types.
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Partitioning the effects of mating and nuptial feeding on the microbiome in gift-giving insects.
Smith, Chad C; Srygley, Robert B; Dietrich, Emma I; Mueller, Ulrich G
2017-04-01
Mating is a ubiquitous social interaction with the potential to influence the microbiome by facilitating transmission, modifying host physiology, and in species where males donate nuptial gifts to females, altering diet. We manipulated mating and nuptial gift consumption in two insects that differ in nuptial gift size, the Mormon cricket Anabrus simplex and the decorated cricket Gryllodes sigillatus, with the expectation that larger gifts are more likely to affect the gut microbiome. Surprisingly, mating, but not nuptial gift consumption, affected the structure of bacterial communities in the gut, and only in Mormon crickets. The change in structure was due to a precipitous drop in the abundance of lactic-acid bacteria in unmated females, a taxon known for their beneficial effects on nutrition and immunity. Mating did not affect phenoloxidase or lysozyme-like antibacterial activity in either species, suggesting that any physiological response to mating on host-microbe interactions is decoupled from systemic immunity. Protein supplementation also did not affect the gut microbiome in decorated crickets, suggesting that insensitivity of gut microbes to dietary protein could contribute to the lack of an effect of nuptial gift consumption. Our study provides experimental evidence that sexual interactions can affect the microbiome and suggests mating can promote beneficial gut bacteria. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.
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Wright, David J.; Brouwer, Lyanne; Mannarelli, Maria-Elena; Burke, Terry; Komdeur, Jan
2016-01-01
The prevalence and significance of precopulatory mate choice remains keenly debated. The major histocompatibility complex (MHC) plays a key role in vertebrate adaptive immunity, and variation at the MHC influences individual survival. Although MHC-dependent mate choice has been documented in certain species, many other studies find no such pattern. This may be, at least in part, because in natural systems constraints may reduce the choices available to individuals and prevent full expression of underlying preferences. We used translocations to previously unoccupied islands to experimentally reduce constraints on female social mate choice in the Seychelles warbler (Acrocephalus sechellensis), a species in which patterns of MHC-dependent extrapair paternity (EPP), but not social mate choice, have been observed. We find no evidence of MHC-dependent social mate choice in the new populations. Instead, we find that older males and males with more microsatellite heterozygosity are more likely to have successfully paired. Our data cannot resolve whether these patterns in pairing were due to male–male competition or female choice. However, our research does suggest that female Seychelles warblers do not choose social mates using MHC class I to increase fitness. It may also indicate that the MHC-dependent EPP observed in the source population is probably due to mechanisms other than female precopulatory mate choice based on MHC cues. PMID:26792973
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Comparing pre- and post-copulatory mate competition using social network analysis in wild crickets
Fisher, David N.; Rodríguez-Muñoz, Rolando
2016-01-01
Sexual selection results from variation in success at multiple stages in the mating process, including competition before and after mating. The relationship between these forms of competition, such as whether they trade-off or reinforce one another, influences the role of sexual selection in evolution. However, the relationship between these 2 forms of competition is rarely quantified in the wild. We used video cameras to observe competition among male field crickets and their matings in the wild. We characterized pre- and post-copulatory competition as 2 networks of competing individuals. Social network analysis then allowed us to determine 1) the effectiveness of precopulatory competition for avoiding postcopulatory competition, 2) the potential for divergent mating strategies, and 3) whether increased postcopulatory competition reduces the apparent reproductive benefits of male promiscuity. We found 1) limited effectiveness of precopulatory competition for avoiding postcopulatory competition; 2) males do not specifically engage in only 1 type of competition; and 3) promiscuous individuals tend to mate with each other, which will tend to reduce variance in reproductive success in the population and highlights the trade-off inherent in mate guarding. Our results provide novel insights into the works of sexual competition in the wild. Furthermore, our study demonstrates the utility of using network analyses to study competitive interactions, even in species lacking obvious social structure. PMID:27174599
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Frye, Cheryl A; Paris, Jason J
2011-01-01
In the midbrain ventral tegmental area (VTA), actions of neurosteroids, such as the progesterone metabolite, 5α-pregnan-3α-ol-20-one (3α,5α-THP), can facilitate mating and influence stress-related processes. Some actions of 3α,5α-THP may occur via positive modulation of GABA(A) receptors (GBRs), or negative modulation of N-methyl-D: -aspartate receptors (NMDARs), to influence anxiety-like behavior; but this is not known. We aimed to assess the role that neurosteroids and stress factors play on intra-VTA NMDAR- and/or GBR-mediated anxiety-like and mating behavior. Estradiol-primed, ovariectomized rats, which were partially or completely adrenalectomized (ADX), received infusions of vehicle, an NMDAR blocker (MK-801; 200 ng), or a GBR antagonist (bicuculline, 100 ng) to the VTA. Rats then received intra-VTA vehicle or a neurosteroidogenesis enhancer (N,N-Dihexyl-2-(4-fluorophenyl)indole-3-acetamide, FGIN 1-27, 5 μg) and anxiety-like and sexual behavior was assessed. Complete, compared to partial, ADX significantly reduced open arm exploration on an elevated plus maze, the proportion of females that engaged in mating, lordosis quotients, pacing of sexual contacts, and defensive aggression towards a sexually vigorous male. Intra-VTA MK-801 enhanced open arm investigation and the proportion of females that engaged in mating. Infusions of either, MK-801 or FGIN 1-27, enhanced lordosis and, when co-administered, FGIN 1-27 attenuated MK-801's lordosis-enhancing effects. Intra-VTA infusions of bicuculline, prior to FGIN 1-27, blocked FGIN 1-27's effects to enhance lordosis. Together, these data suggest that reduced NMDAR activity in the VTA may influence motivation to explore and engage in sexual behavior. These data suggest that neurosteroid actions at NMDARs and GBRs in the VTA are important for exploration and/or sexual behavior.
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Paris, Jason J.
2013-01-01
Rationale In the midbrain ventral tegmental area (VTA), actions of neurosteroids, such as the progesterone metabolite, 5α-pregnan-3α-ol-20-one (3α,5α-THP), can facilitate mating and influence stress-related processes. Some actions of 3α,5α-THP may occur via positive modulation of GABAA receptors (GBRs), or negative modulation of N-methyl-D-aspartate receptors (NMDARs), to influence anxiety-like behavior; but this is not known. Objectives We aimed to assess the role that neurosteroids and stress factors play on intra-VTA NMDAR- and/or GBR-mediated anxiety-like and mating behavior. Methods Estradiol-primed, ovariectomized rats, which were partially or completely adrenalectomized (ADX), received infusions of vehicle, an NMDAR blocker (MK-801; 200 ng), or a GBR antagonist (bicuculline, 100 ng) to the VTA. Rats then received intra-VTA vehicle or a neurosteroidogenesis enhancer (N,N-Dihexyl-2-(4-fluorophenyl)indole-3-acetamide, FGIN 1-27, 5 μg) and anxiety-like and sexual behavior was assessed. Results Complete, compared to partial, ADX significantly reduced open arm exploration on an elevated plus maze, the proportion of females that engaged in mating, lordosis quotients, pacing of sexual contacts, and defensive aggression towards a sexually vigorous male. Intra-VTA MK-801 enhanced open arm investigation and the proportion of females that engaged in mating. Infusions of either, MK-801 or FGIN 1-27, enhanced lordosis and, when co-administered, FGIN 1-27 attenuated MK-801’s lordosis-enhancing effects. Intra-VTA infusions of bicuculline, prior to FGIN 1-27, blocked FGIN 1-27’s effects to enhance lordosis. Conclusions Together, these data suggest that reduced NMDAR activity in the VTA may influence motivation to explore and engage in sexual behavior. These data suggest that neurosteroid actions at NMDARs and GBRs in the VTA are important for exploration and/or sexual behavior. PMID:20878318
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Mate and Dart: An Instrument Package for Characterizing Solar Energy and Atmospheric Dust on Mars
NASA Technical Reports Server (NTRS)
Landis, Geoffrey A.; Jenkins, Phillip; Scheiman, David; Baraona, Cosmo
2000-01-01
The MATE (Mars Array Technology Experiment) and DART (Dust Accumulation and Removal Test) instruments were developed to fly as part of the Mars ISPP Precursor (MIP) experiment on the (now postponed) Mars-2001 Surveyor Lander. MATE characterizes the solar energy reaching the surface of Mars, and measures the performance and degradation of solar cells under Martian conditions. DART characterizes the dust environment of Mars, measures the effect of settled dust on solar arrays, and investigates methods to mitigate power loss due to dust accumulation.
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Automatic attention towards face or body as a function of mating motivation.
Lu, Hui Jing; Chang, Lei
2012-03-22
Because women's faces and bodies carry different cues of reproductive value, men may attend to different perceptual cues as functions of their long-term versus short-term mating motivations. We tested this hypothesis in three experiments on 135 male and 132 female participants. When influenced by short-term rather than long-term mating motivations, men's attention was captured by (Study 1), was shifted to (Study 2), and was distracted by (Study 3) the waist/hip area rather than the face on photographs of attractive women. Similar effects were not found among the female participants in response to photographs of attractive men. These results support the evolutionary view that, similar to the attentional selectivity found in other domains of life, male perceptual attention has evolved to selectively capture and hold reproductive information about the opposite sex as a function of short-term versus long-term mating goals.
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Assortative Mating for Emotional Intelligence.
Śmieja, Magdalena; Stolarski, Maciej
2018-01-01
Assortative mating has been studied on a broad range of variables, including intelligence and personality traits. In the present study we analysed the effect of assortative mating for ability emotional intelligence (EI) on a sample of heterosexual couples ( N = 382), including dating and married couples. Correlation analyses revealed moderate similarity of Pearson's r = .27 for general EI score, and was slightly weaker (from .18 to .23) for branch scores. Regression analyses showed that the Perception branch was the strongest single predictor of a partner's general EI score, both in males and females. Continuous parameter estimation (CPEM) revealed that the magnitude of the correlation does not increase with age, thus it is highly possible that the obtained similarity reflects initial assortment (i.e., similarity at the starting point of the relationship), rather than convergence (i.e., increasing similarity with time). It seems that EI is a significant factor influencing mate assortment processes.
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Zhang, Jibin; Huang, Ling; He, Jin; Tomberlin, Jeffery K; Li, Jianhong; Lei, Chaoliang; Sun, Ming; Liu, Ziduo; Yu, Ziniu
2010-01-01
Current methods for mass-rearing black soldier flies, Hermetia illucens (L.) (Diptera: Stratiomyidae), in the laboratory are dependent on sunlight. Quartz-iodine lamps and rare earth lamps were examined as artificial light sources for stimulating H. illucens to mate and lay eggs. Sunlight was used as the control. Adults in the quartz-iodine lamp treatment had a mating rate of 61% of those in the sunlight control. No mating occurred when the rare earth lamp was used as a substitute. Egg hatch for the quartz-iodine lamp and sunlight treatments occurred in approximately 4 days, and the hatch rate was similar between these two treatments. Larval and pupal development under these treatments required approximately 18 and 15 days at 28°C, respectively. Development of methods for mass rearing of H. illucens using artificial light will enable production of this fly throughout the year without investing in greenhouse space or requiring sunlight.
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Computational fluid dynamics analysis of a maglev centrifugal left ventricular assist device.
Burgreen, Greg W; Loree, Howard M; Bourque, Kevin; Dague, Charles; Poirier, Victor L; Farrar, David; Hampton, Edward; Wu, Z Jon; Gempp, Thomas M; Schöb, Reto
2004-10-01
The fluid dynamics of the Thoratec HeartMate III (Thoratec Corp., Pleasanton, CA, U.S.A.) left ventricular assist device are analyzed over a range of physiological operating conditions. The HeartMate III is a centrifugal flow pump with a magnetically suspended rotor. The complete pump was analyzed using computational fluid dynamics (CFD) analysis and experimental particle imaging flow visualization (PIFV). A comparison of CFD predictions to experimental imaging shows good agreement. Both CFD and experimental PIFV confirmed well-behaved flow fields in the main components of the HeartMate III pump: inlet, volute, and outlet. The HeartMate III is shown to exhibit clean flow features and good surface washing across its entire operating range.
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Junca, Pierre; Carcaud, Julie; Moulin, Sibyle; Garnery, Lionel; Sandoz, Jean-Christophe
2014-01-01
In Pavlovian conditioning, animals learn to associate initially neutral stimuli with positive or negative outcomes, leading to appetitive and aversive learning respectively. The honeybee (Apis mellifera) is a prominent invertebrate model for studying both versions of olfactory learning and for unraveling the influence of genotype. As a queen bee mates with about 15 males, her worker offspring belong to as many, genetically-different patrilines. While the genetic dependency of appetitive learning is well established in bees, it is not the case for aversive learning, as a robust protocol was only developed recently. In the original conditioning of the sting extension response (SER), bees learn to associate an odor (conditioned stimulus - CS) with an electric shock (unconditioned stimulus - US). This US is however not a natural stimulus for bees, which may represent a potential caveat for dissecting the genetics underlying aversive learning. We thus first tested heat as a potential new US for SER conditioning. We show that thermal stimulation of several sensory structures on the bee’s body triggers the SER, in a temperature-dependent manner. Moreover, heat applied to the antennae, mouthparts or legs is an efficient US for SER conditioning. Then, using microsatellite analysis, we analyzed heat sensitivity and aversive learning performances in ten worker patrilines issued from a naturally inseminated queen. We demonstrate a strong influence of genotype on aversive learning, possibly indicating the existence of a genetic determinism of this capacity. Such determinism could be instrumental for efficient task partitioning within the hive. PMID:24828422
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Paton, Doug; Touré, Mahamoudou; Sacko, Adama; Coulibaly, Mamadou B; Traoré, Sékou F; Tripet, Frédéric
2013-01-01
Anopheles gambiae sensu stricto, the main vector of malaria in Africa, is characterized by its vast geographical range and complex population structure. Assortative mating amongst the reproductively isolated cryptic forms that co-occur in many areas poses unique challenges for programs aiming to decrease malaria incidence via the release of sterile or genetically-modified mosquitoes. Importantly, whether laboratory-rearing affects the ability of An. gambiae individuals of a given cryptic taxa to successfully mate with individuals of their own form in field conditions is still unknown and yet crucial for mosquito-releases. Here, the independent effects of genetic and environmental factors associated with laboratory rearing on male and female survival, mating success and assortative mating were evaluated in the Mopti form of An. gambiae over 2010 and 2011. In semi-field enclosures experiments and despite strong variation between years, the overall survival and mating success of male and female progeny from a laboratory strain was not found to be significantly lower than those of the progeny of field females from the same population. Adult progeny from field-caught females reared at the larval stage in the laboratory and from laboratory females reared outdoors exhibited a significant decrease in survival but not in mating success. Importantly, laboratory individuals reared as larvae indoors were unable to mate assortatively as adults, whilst field progeny reared either outdoors or in the laboratory, as well as laboratory progeny reared outdoors all mated significantly assortatively. These results highlight the importance of genetic and environment interactions for the development of An. gambiae's full mating behavioral repertoire and the challenges this creates for mosquito rearing and release-based control strategies.
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Preferential Mating in Symmetric Multilocus Systems: Limits for Multiallelism and for Many Loci
Raper, J.
1982-01-01
Models in which general forms of preferential mating have been superimposed on the framework of the symmetric heterozygosity selection regime have been examined previously with respect to the existence and local stability of a central polymorphic equilibrium. The results are now extended to produce the limiting form of the stability conditions in two cases: First, where the number of alleles per locus is assumed to be very large; second, where the number of loci affecting the character is very large. It is argued that some type of frequency dependence in the mating pattern must be included, and a particular case is examined in detail. It is shown that multiallelism is ambiguous in its effect on stability, while an increasing number of loci, at least under zero linkage, leads to a simple stability condition which is analogous to the one-locus heterosis principle. Assortative mating appears to be more likely to produce a stable central polymorphism under high levels of allelism than is sexual selection, but is relatively very much weaker than sexual or viability selection if the number of loci involved is large. PMID:17246061
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Senior, Alistair McNair; Nakagawa, Shinichi; Grimm, Volker
2014-01-01
Females may select a mate based on signalling traits that are believed to accurately correlate with heritable aspects of male quality. Anthropogenic actions, in particular chemicals released into the environment, are now disrupting the accuracy of mating signals to convey information about male quality. The long-term prediction for disrupted mating signals is most commonly loss of female preference. Yet, this prediction has rarely been tested using quantitative models. We use agent-based models to explore the effects of rapid disruption of mating signals. In our model, a gene determines survival. Males signal their level of genetic quality via a signal trait, which females use to select a mate. We allowed this system of sexual selection to become established, before introducing a disruption between the male signal trait and quality, which was similar in nature to that induced by exogenous chemicals. Finally, we assessed the capacity of the system to recover from this disruption. We found that within a relatively short time frame, disruption of mating signals led to a lasting loss of female preference. Decreases in mean viability at the population-level were also observed, because sexual-selection acting against newly arising deleterious mutations was relaxed. The ability of the population to recover from disrupted mating signals was strongly influenced by the mechanisms that promoted or maintained genetic diversity in traits under sexual selection. Our simple model demonstrates that environmental perturbations to the accuracy of male mating signals can result in a long-term loss of female preference for those signals within a few generations. What is more, the loss of this preference can have knock-on consequences for mean population fitness. PMID:25047080
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Zhang, Xiaohong; He, Xiao; Baker, Joseph; Tama, Florence; Chang, Geoffrey; Wright, Stephen H.
2012-01-01
The x-ray structure of the prototypic MATE family member, NorM from Vibrio cholerae, reveals a protein fold composed of 12 transmembrane helices (TMHs), confirming hydropathy analyses of the majority of (prokaryotic and plant) MATE transporters. However, the mammalian MATEs are generally predicted to have a 13th TMH and an extracellular C terminus. Here we affirm this prediction, showing that the C termini of epitope-tagged, full-length human, rabbit, and mouse MATE1 were accessible to antibodies from the extracellular face of the membrane. Truncation of these proteins at or near the predicted junction between the 13th TMH and the long cytoplasmic loop that precedes it resulted in proteins that (i) trafficked to the membrane and (ii) interacted with antibodies only after permeabilization of the plasma membrane. CHO cells expressing rbMate1 truncated at residue Gly-545 supported levels of pH-sensitive transport similar to that of cells expressing the full-length protein. Although the high transport rate of the Gly-545 truncation mutant was associated with higher levels of membrane expression (than full-length MATE1), suggesting the 13th TMH may influence substrate translocation, the selectivity profile of the mutant indicated that TMH13 has little impact on ligand binding. We conclude that the functional core of MATE1 consists of 12 (not 13) TMHs. Therefore, we used the x-ray structure of NorM to develop a homology model of the first 12 TMHs of MATE1. The model proved to be stable in molecular dynamic simulations and agreed with topology evident from preliminary cysteine scanning of intracellular versus extracellular loops. PMID:22722930
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Colpo, Ana C; Rosa, Hemerson; Lima, Maria Eduarda; Pazzini, Camila Eliza F; de Camargo, Vanessa B; Bassante, Felipa E M; Puntel, Robson; Ávila, Daiana Silva; Mendez, Andreas; Folmer, Vanderlei
2016-10-15
Chimarrão or mate is a popular beverage from South America that is drank with successive infusions. Although yerba mate extracts have been widely studied, few studies have described the extract contents in beverages. Using yerba mate samples from Brazil, Argentina, and Uruguay, we examined the extract chromatographic profiles, total polyphenol content and their capacities to chelate iron. In addition, we analyzed antioxidant activity by examining the ability of the extracts to scavenge DPPH and NO. Our results showed that the amount of extracted compound was highest in yerba mate extract from Uruguay, followed by Argentina, then Brazil. Herbs from all three areas had a significant capacity to inhibit DPPH and NO free radicals. The Brazilian and Uruguayan herbs had an 80% iron chelation capacity (p<0.001), while the iron chelation capacity of the Argentinean herb was lower but still significant (p⩽0.05). We conclude that the compound concentration decreases with successive extractions, while the antioxidant capacity is maintained at significant levels. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Cruzan, Mitchell B; Barrett, Spencer C H
2016-03-01
Variation in the mating system of hermaphroditic plant populations is determined by interactions between genetic and environmental factors operating via both pre- and postmating processes. Models predicting the maintenance of intermediate outcrossing rates in animal-pollinated plants often assume that the mating system is primarily controlled by floral morphology and pollinator availability, but rarely has the influence of postpollination processes on variation in outcrossing been examined. We investigated the influence of stylar discrimination between illegitimate and legitimate pollen-tube growth and the pollen-load capacity of stigmas on mating-system variation in the annual, tristylous species Eichhornia paniculata using controlled crosses and genetic markers. This species exhibits an exceptionally broad range of outcrossing rates in natural populations. There was significant variation among populations in the pollen-load capacity of stigmas and the ability of styles to discriminate between illegitimate vs. legitimate pollen. There was strong correspondence between stylar-discrimination ability and variation in outcrossing rate among populations and style morphs. The combination of stigmatic pollen-load capacity and stylar discrimination explained more than 80% of the variation in outcrossing rates among populations. The finding that stigmatic pollen-load capacity and stylar-discrimination ability contributed significantly to explaining the wide range of outcrossing rates in E. paniculata suggests that postpollination mechanisms play an important role in governing mating patterns in this species. The difference in levels of stylar discrimination between outcrossing and selfing populations may reflect a trade-off between selection for increased outcrossing and greater reproductive assurance. © 2016 Botanical Society of America.
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Role of social interactions in dynamic patterns of resource patches and forager aggregation
Tania, Nessy; Vanderlei, Ben; Heath, Joel P.; Edelstein-Keshet, Leah
2012-01-01
The dynamics of resource patches and species that exploit such patches are of interest to ecologists, conservation biologists, modelers, and mathematicians. Here we consider how social interactions can create unique, evolving patterns in space and time. Whereas simple prey taxis (with consumable prey) promotes spatial uniform distributions, here we show that taxis in producer–scrounger groups can lead to pattern formation. We consider two types of foragers: those that search directly (“producers”) and those that exploit other foragers to find food (“scroungers” or exploiters). We show that such groups can sustain fluctuating spatiotemporal patterns, akin to “waves of pursuit.” Investigating the relative benefits to the individuals, we observed conditions under which either strategy leads to enhanced success, defined as net food consumption. Foragers that search for food directly have an advantage when food patches are localized. Those that seek aggregations of group mates do better when their ability to track group mates exceeds the foragers’ food-sensing acuity. When behavioral switching or reproductive success of the strategies is included, the relative abundance of foragers and exploiters is dynamic over time, in contrast with classic models that predict stable frequencies. Our work shows the importance of considering two-way interaction—i.e., how food distribution both influences and is influenced by social foraging and aggregation of predators. PMID:22745167
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Iglesias-Carrasco, M; Head, M L; Jennions, M D; Cabido, C
2017-10-01
Selection can favour phenotypic plasticity in mate choice in response to environmental factors that alter the costs and benefits of being choosy, or of choosing specific mates. Human-induced environmental change could alter sexual selection by affecting the costs of mate choice, or by impairing the ability of individuals to identify preferred mates. For example, variation in mate choice could be driven by environmentally induced differences in body condition (e.g. health) that change the cost of choosiness, or by environmental effects on the ability to detect or discriminate sexual signals. We teased apart these possibilities experimentally, by comparing female mate choice in the palmate newt Lissotriton helveticus between environments that mimic water from either native oak forests or exotic eucalypt plantations. In laboratory two-choice mate trials in clean water, females with prolonged exposure (21 days) to waterborne chemicals leached from eucalypt leaves did not preferentially associate with the male with a stronger immune response, but females exposed to water with chemicals from oak leaves did. In contrast, female choice was unaffected by the immediate presence or absence of eucalypt leachates during mate choice (using only females previously held in oak-treated water). The habitat-related change in female choice we observed is likely to be driven by effects of eucalypt leachates on female physiology, rather than immediate inhibition of pheromone transmission or blocking of pheromone reception. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.
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Assortative mating and mutation diffusion in spatial evolutionary systems
NASA Astrophysics Data System (ADS)
Paley, C. J.; Taraskin, S. N.; Elliott, S. R.
2010-04-01
The influence of spatial structure on the equilibrium properties of a sexual population model defined on networks is studied numerically. Using a small-world-like topology of the networks as an investigative tool, the contributions to the fitness of assortative mating and of global mutant spread properties are considered. Simple measures of nearest-neighbor correlations and speed of spread of mutants through the system have been used to confirm that both of these dynamics are important contributory factors to the fitness. It is found that assortative mating increases the fitness of populations. Quick global spread of favorable mutations is shown to be a key factor increasing the equilibrium fitness of populations.
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Not all sex ratios are equal: the Fisher condition, parental care and sexual selection.
Jennions, Michael D; Fromhage, Lutz
2017-09-19
The term 'sex roles' encapsulates male-female differences in mate searching, competitive traits that increase mating/fertilization opportunities, choosiness about mates and parental care. Theoretical models suggest that biased sex ratios drive the evolution of sex roles. To model sex role evolution, it is essential to note that in most sexually reproducing species (haplodiploid insects are an exception), each offspring has one father and one mother. Consequently, the total number of offspring produced by each sex is identical, so the mean number of offspring produced by individuals of each sex depends on the sex ratio (Fisher condition). Similarly, the total number of heterosexual matings is identical for each sex. On average, neither sex can mate nor breed more often when the sex ratio is even. But equally common in which sex ratio? The Fisher condition only applies to some reproductive measures (e.g. lifetime offspring production or matings) for certain sex ratios (e.g. operational or adult sex ratio; OSR, ASR). Here, we review recent models that clarify whether a biased OSR, ASR or sex ratio at maturation (MSR) have a causal or correlational relationship with the evolution of sex differences in parental care and competitive traits-two key components of sex roles. We suggest that it is more fruitful to understand the combined effect of the MSR and mortality rates while caring and competing than that of the ASR itself. In short, we argue that the ASR does not have a causal role in the evolution of parental care. We point out, however, that the ASR can be a cue for adaptive phenotypic plasticity in how each sex invests in parental care.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'. © 2017 The Author(s).
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Radio-induced inherited sterility in Heliothis zea (Boddie)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Carpenter, J.E.
1985-01-01
Heliothis zea (Boddie) (Lepidoptera: Noctuidae) males and females were irradiated with substerilizing doses of radiation. These moths were inbred and outcrossed and observed for their ability to reproduce. The inherited deleterious effects resulting from the irradiated P/sub 1/ males were recorded for several generations. Larvae from both irradiated (10 krad) and normal parents were compared for their ability to survive under field conditions on whole-stage sweet corn and these results were compared with those from a laboratory study using meridic diet. Irradiated males and females and F/sub 1/ males from an irradiated (10 krad) male x normal female cross weremore » released in the field and in field cages and observed for their ability to search/attract and secure a mate. Females that had mated with normal and irradiated (10 krad) males were studied to determine the effect of different mating histories on the subsequent mating propensity of the females. A 10-krad dose of radiation induced deleterious effects which were inherited through the F/sub 2/ generation. These radiation-induced deleterious effects were similar to those reported in other species of Lepidoptera. The relationship between the survival of normal larvae and larvae from irradiated parents was similar under laboratory and field rearing conditions. Females mated to normal males and males irradiated with 10 krad had the same mating propensity and experienced the same intermating interval. These effects of substerilizing doses of radiation and inherited sterility on the reproductive ability and behavior of H. zea suggest that a great potential exists for population suppression.« less
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Watanabe, Shigeru
2015-10-01
The aim of this study was to determine whether previous exposure to a drug affects the social facilitation of conditioned place preference (CPP) for a drug-injected cage mate. Twenty-two male C57/BL6J mice received drug injections (methamphetamine or morphine) and 22 male C57/BL6J mice received saline injections. All 44 mice then received CPP training, during which one compartment of a conventional CPP apparatus was associated with a drug-injected cage mate (stimulus mouse) and the other compartment was associated with a saline-injected cage mate (stimulus mouse). The subject mice did not receive any drug injection during this CPP training. Time spent in the compartment associated with the drug-injected cage mate was measured before and after training. Subject mice that had previously received methamphetamine injections showed an increase in the time spent in the compartment associated with the methamphetamine-injected cage mate after CPP training. This effect was not observed in subject mice that had previously received saline injections. Subject mice did not show an increase in the time spent in the compartment associated with the morphine-injected cage mate irrespective of whether they had previously received morphine or saline injections. Therefore, in agreement with previous reports, common experience with methamphetamine induced reinforcing properties, but that with morphine did not.
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Valsecchi, Paola; Natoli, Eugenia
2014-01-01
Mating and reproductive outcome is often determined by the simultaneous operation of different mechanisms like intra-sexual competition, mating preferences and sexual coercion. The present study investigated how social variables affected mating outcome in a pack of free-ranging dogs, a species supposed to have lost most features of the social system of wolves during domestication. We found that, although the pack comprised multiple breeding individuals, both male copulation success and female reproductive success were positively influenced by a linear combination of dominance rank, age and leadership. Our results also suggest that mate preferences affect mating outcome by reinforcing the success of most dominant individuals. In particular, during their oestrous period bitches clearly searched for the proximity of high-ranking males who displayed affiliative behaviour towards them, while they were more likely to reject the males who intimidated them. At the same time, male courting effort and male-male competition for receptive females appeared to be stronger in the presence of higher-ranking females, suggesting a male preference for dominant females. To our knowledge, these results provide the first clear evidence of social regulation of reproductive activities in domestic dogs, and suggest that some common organizing mechanisms may contribute to shape the social organization of both dogs and wolves. PMID:24905360
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Strandh, Maria; Westerdahl, Helena; Pontarp, Mikael; Canbäck, Björn; Dubois, Marie-Pierre; Miquel, Christian; Taberlet, Pierre; Bonadonna, Francesco
2012-11-07
Mate choice for major histocompatibility complex (MHC) compatibility has been found in several taxa, although rarely in birds. MHC is a crucial component in adaptive immunity and by choosing an MHC-dissimilar partner, heterozygosity and potentially broad pathogen resistance is maximized in the offspring. The MHC genotype influences odour cues and preferences in mammals and fish and hence olfactory-based mate choice can occur. We tested whether blue petrels, Halobaena caerulea, choose partners based on MHC compatibility. This bird is long-lived, monogamous and can discriminate between individual odours using olfaction, which makes it exceptionally well suited for this analysis. We screened MHC class I and II B alleles in blue petrels using 454-pyrosequencing and quantified the phylogenetic, functional and allele-sharing similarity between individuals. Partners were functionally more dissimilar at the MHC class II B loci than expected from random mating (p = 0.033), whereas there was no such difference at the MHC class I loci. Phylogenetic and non-sequence-based MHC allele-sharing measures detected no MHC dissimilarity between partners for either MHC class I or II B. Our study provides evidence of mate choice for MHC compatibility in a bird with a high dependency on odour cues, suggesting that MHC odour-mediated mate choice occurs in birds.
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Wilson, Robbie S; Condon, Catriona H L; Johnston, Ian A
2007-11-29
The mating system of eastern mosquito fish (Gambusia holbrooki) is dominated by male sexual coercion, where all matings are forced and females never appear to cooperate and actively avoid all attempts. Previous research has shown that male G. holbrooki offer a model system for examining the benefits of reversible thermal acclimation for reproductive success, but examining the benefits to female avoidance behaviour has been difficult. In this study, we examined the ability of non-male-deprived female G. holbrooki to avoid forced-coercive matings following acclimation to either 18 or 30 degrees C for six weeks (12h light:12h dark photoperiod). Thermal acclimation of burst and sustained swimming performance was also assessed, as these traits are likely to underlie their ability to avoid forced matings. There was no influence of thermal acclimation on the burst swimming performance of female G. holbrooki over the range 18-30 degrees C; however, sustained swimming performance was significantly lower in the warm- than the cool-acclimation group. For mating behaviour, we tested the hypothesis that acclimation would enhance the ability of female G. holbrooki to avoid forced matings at their host acclimation temperature relative to females acclimated to another environment. However, our hypothesis was not supported. The rate of copulations was almost three times greater for females acclimated to 30 degrees C than 18 degrees C when tested at 30 degrees C, indicating that they possess the ability to alter their avoidance behaviour to 'allow' more copulations in some environments. Coupled with previous studies, female G. holbrooki appear to have greater control on the outcome of coercive mating attempts than previously considered and can alter their propensity to receive forced matings following thermal acclimation. The significance of this change in female mating-avoidance behaviours with thermal acclimation remains to be explored.
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"Nice guys finish last": influence of mate choice on reproductive success in Long-Evans rats.
Winland, C; Bolton, J L; Ford, B; Jampana, S; Tinker, J; Frohardt, R J; Guarraci, F A; Zewail-Foote, M
2012-02-01
The present study was designed to determine if male physiology and male reproductive behavior predict reproductive success in Long-Evans rats. Mating behavior was observed in sexually naïve, naturally cycling female rats during behavioral estrous that were given the opportunity to mate with two males simultaneously. DNA analysis of offspring born following these mating encounters was used to identify the paternity of each pup. In order to assess the effect of mate choice during these mating encounters on reproductive success, one male rat in each pair was categorized as the preferred mate if the female spent more time (>50%) with him during the mating test of the present study. Furthermore, each male in the pairs was categorized as "attractive" or "non-attractive" by computing the number of females that preferred each male across many mating tests. Similar to results reported in Lovell et al. (2007), during 76% of these mating tests the same male rat in each pair was preferred by different female rats. Overall attractiveness of individual male rats predicted reproductive success in the present study. Interestingly, "attractive" males sired significantly FEWER pups than "non-attractive" males. Neither behavioral (e.g., latency to first sexual stimulation, number of sexual stimulations) nor physiological measures (e.g., body weight, urinary testosterone levels) of male rats predicted their reproductive success. In conclusion, the present results indicate that certain features of some males are more attractive to females, but attractive males are at a reproductive disadvantage (as measured by the number of pups sired). Although basal urinary testosterone levels did not differ between males that sired the majority of pups in a litter and males that sired few or none of the pups in a litter, aggression and/or other physiological measures of fertility (e.g., penile reflexes) may differ between males that are attractive to females and those that have a reproductive advantage. Copyright © 2011 Elsevier Inc. All rights reserved.
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NASA Astrophysics Data System (ADS)
Rick, Ingolf P.; Bakker, Theo C. M.
2008-07-01
Animal colour signals serve important functions in intraspecific interactions, including species recognition, mate choice and agonistic behaviour. An increasing interest concerns ultraviolet (UV) wavelengths, for instance studies on the effect of UV in mating decisions. More recently, some studies also established that UV signals affect intrasexual interactions. We studied the role of UV during aggressive encounters between male three-spined sticklebacks ( Gasterosteus aculeatus), a species in which UV has an effect on female and male mate choice and shoaling behaviour. To that aim, we compared the aggressive response of a territorial male to male intruders, either seen in UV-including (UV+) or UV-lacking (UV-) conditions. Our prediction was that, if UV wavelengths are used in male-male competition, a territorial male should show less competitive behaviour towards an intruder representing a lower threat, i.e. the one presented without UV light. Male sticklebacks showed significantly lower levels of aggression towards male opponents lacking an UV component to their coloration than male opponents possessing this colour component. Discrimination was not influenced by a difference in brightness between the UV+ and UV- stimuli. Finally, we present some reflectance-spectrophotometrical data of two skin regions (cheek and abdomen) of the experimental males and analysed relationships between colorimetric variables, body variables and behaviour. Our study emphasises that UV visual cues are of importance in different communicational tasks in the three-spined stickleback.
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Environmental quality alters female costs and benefits of evolving under enforced monogamy.
Grazer, Vera M; Demont, Marco; Michalczyk, Łukasz; Gage, Matthew J G; Martin, Oliver Y
2014-02-05
Currently many habitats suffer from quality loss due to environmental change. As a consequence, evolutionary trajectories might shift due to environmental effects and potentially increase extinction risk of resident populations. Nevertheless, environmental variation has rarely been incorporated in studies of sexual selection and sexual conflict, although local environments and individuals' condition undoubtedly influence costs and benefits. Here, we utilise polyandrous and monogamous selection lines of flour beetles, which evolved in presence or absence of sexual selection for 39 generations. We specifically investigated effects of low vs. standard food quality (i.e. stressful vs. benign environments) on reproductive success of cross pairs between beetles from the contrasting female and male selection histories to assess gender effects driving fitness. We found a clear interaction of food quality, male selection history and female selection history. Monogamous females generally performed more poorly than polyandrous counterparts, but reproductive success was shaped by selection history of their mates and environmental quality. When monogamous females were paired with polyandrous males in the standard benign environment, females seemed to incur costs, possibly due to sexual conflict. In contrast, in the novel stressful environment, monogamous females profited from mating with polyandrous males, indicating benefits of sexual selection outweigh costs. Our findings suggest that costs and benefits of sexually selected adaptations in both sexes can be profoundly altered by environmental quality. With regard to understanding possible impacts of environmental change, our results further show that the ecology of mating systems and associated selection pressures should be considered in greater detail.
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Singh, Karan; Samant, Manas Arun; Tom, Megha Treesa; Prasad, Nagaraj Guru
2016-01-01
Background In Drosophila melanogaster the fitness of males depends on a broad array of reproductive traits classified as pre- and post-copulatory traits. Exposure to cold stress, can reduce sperm number, male mating ability and courtship behavior. Therefore, it is expected that the adaptation to cold stress will involve changes in pre- and post-copulatory traits. Such evolution of reproductive traits in response to cold stress is not well studied. Methods We selected replicate populations of D. melanogaster for resistance to cold shock. Over 37–46 generations of selection, we investigated pre- and post-copulatory traits such as mating latency, copulation duration, mating frequency, male fertility, fitness (progeny production) and sperm competitive ability in male flies subjected to cold shock and those not subjected to cold shock. Results We found that post cold shock, the males from the selected populations had a significantly lower mating latency along with, higher mating frequency, fertility, sperm competitive ability and number of progeny relative to the control populations. Conclusion While most studies of experimental evolution of cold stress resistance have documented the evolution of survivorship in response to selection, our study clearly shows that adaptation to cold stress involves rapid changes in the pre- and post-copulatory traits. Additionally, improved performances under stressful conditions need not necessarily trade-off with performance under benign conditions. PMID:27093599
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Dunning, Jeffery L.; Pant, Santosh; Bass, Aaron; Coburn, Zachary; Prather, Jonathan F.
2014-01-01
In the process of mate selection by female songbirds, male suitors advertise their quality through reproductive displays in which song plays an important role. Females evaluate the quality of each signal and the associated male, and the results of that evaluation guide expression of selective courtship displays. Some studies reveal broad agreement among females in their preferences for specific signal characteristics, indicating that those features are especially salient in female mate choice. Other studies reveal that females differ in their preference for specific characteristics, indicating that in those cases female evaluation of signal quality is influenced by factors other than simply the physical properties of the signal. Thus, both the physical properties of male signals and specific traits of female signal evaluation can impact female mate choice. Here, we characterized the mate preferences of female Bengalese finches. We found that calls and copulation solicitation displays are equally reliable indicators of female preference. In response to songs from an array of males, each female expressed an individual-specific song preference, and those preferences were consistent across tests spanning many months. Across a population of females, songs of some males were more commonly preferred than others, and females preferred female-directed songs more than undirected songs, suggesting that some song features are broadly attractive. Preferences were indistinguishable for females that did or did not have social experience with the singers, indicating that female preference is strongly directed by song features rather than experiences associated with the singer. Analysis of song properties revealed several candidate parameters that may influence female evaluation. In an initial investigation of those parameters, females could be very selective for one song feature yet not selective for another. Therefore, multiple song parameters are evaluated independently. Together these findings reveal the nature of signal evaluation and mate choice in this species. PMID:24558501
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Bahr, Angela; Wilson, Anthony B
2011-05-10
Both natural and sexual selection are thought to influence genetic diversity, but the study of the relative importance of these two factors on ecologically-relevant traits has traditionally focused on species with conventional sex-roles, with male-male competition and female-based mate choice. With its high variability and significance in both immune function and olfactory-mediated mate choice, the major histocompatibility complex (MHC/MH) is an ideal system in which to evaluate the relative contributions of these two selective forces to genetic diversity. Intrasexual competition and mate choice are both reversed in sex-role reversed species, and sex-related differences in the detection and use of MH-odor cues are expected to influence the intensity of sexual selection in such species. The seahorse, Hippocampus abdominalis, has an exceptionally highly developed form of male parental care, with female-female competition and male mate choice. Here, we demonstrate that the sex-role reversed seahorse has a single MH class II beta-chain gene and that the diversity of the seahorse MHIIβ locus and its pattern of variation are comparable to those detected in species with conventional sex roles. Despite the presence of only a single gene copy, intralocus MHIIβ allelic diversity in this species exceeds that observed in species with multiple copies of this locus. The MHIIβ locus of the seahorse exhibits a novel expression domain in the male brood pouch. The high variation found at the seahorse MHIIβ gene indicates that sex-role reversed species are capable of maintaining the high MHC diversity typical in most vertebrates.Whether such species have evolved the capacity to use MH-odor cues during mate choice is presently being investigated using mate choice experiments. If this possibility can be rejected, such systems would offer an exceptional opportunity to study the effects of natural selection in isolation, providing powerful comparative models for understanding the relative importance of selective factors in shaping patterns of genetic variation.
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Toward a theory of topopatric speciation: The role of genetic assortative mating
NASA Astrophysics Data System (ADS)
Schneider, David M.; do Carmo, Eduardo; Martins, Ayana B.; de Aguiar, Marcus A. M.
2014-09-01
We discuss a minimalist model of assortative mating for sexually reproducing haploid individuals with two biallelic loci. Assortativeness is introduced in the model by preventing mating between individuals whose alleles differ at both loci. Using methods of dynamical systems and population genetics we provide a full description of the evolution of the system for the case of very large populations. We derive the equations governing the evolution of haplotype frequencies and study the equilibrium solutions, stability, and speed of convergence to equilibrium. We find a constant of motion which allows us to introduce a geometrical construction that makes it straightforward to predict the fate of initial conditions. Finally, we discuss the consequences of this class of assortative mating models, including their possible extensions and implications for sympatric and topopatric speciation.
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2018-01-01
The use of medicinal plants mixed with yerba mate (Ilex paraguariensis) has been poorly studied in the ethnopharmacological literature so far. The Paraguayan Mestizo people have the longest tradition of using the yerba mate beverage, apart from the indigenous Guarani people. This study analyses the role of yerba mate and medicinal plants in the treatment of illnesses within Paraguayan folk medicine. The research was conducted among 100 Paraguayan migrants living in Misiones, Argentina, in 2014 and 2015. Yerba mate is not considered to be a medicinal plant by its own virtues but is culturally a very important type of medicinal plant intake. Ninety-seven species are employed in hot and cold versions of the yerba mate beverage. The most important species are as follows: Allophylus edulis (highest number of citations), Aristolochia triangularis (highest relative importance value), and Achyrocline flaccida and Achyrocline tomentosa (highest score by Index of Agreement on Species). The plants are used in the treatment of 18 medicinal categories, which include illnesses traditionally treated with plants: digestive system, humoral medicine, and relatively new health conditions such as diabetes, hypertension, and high levels of cholesterol. Newly incorporated medicinal plants, such as Moringa oleifera, are ingested predominantly or exclusively with the mate beverage. PMID:29725356
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Rogers, D W; Baker, R H; Chapman, T; Denniff, M; Pomiankowski, A; Fowler, K
2005-05-01
Traditionally it was thought that fitness-related traits such as male mating frequency, with a history of strong directional selection, should have little additive genetic variance and thus respond asymmetrically to bidirectional artificial selection. However, recent findings and theory suggest that a balance between selection for increased male mating frequency and opposing selection pressures on physiologically linked traits will cause male mating frequency to have high additive genetic variation and hence respond symmetrically to selection. We tested these hypotheses in the stalk-eyed fly, Cyrtodiopsis dalmanni, in which males hold harems comprising many females and so have the opportunity to mate at extremely high frequencies. We subjected male stalk-eyed flies to artificial selection for increased ('high') and decreased ('low') mating frequency in the presence of ecologically realistic, high numbers of females. High line males mated significantly more often than control or low line males. The direct response to selection was approximately symmetric in the high and low lines, revealing high additive genetic variation for, and no significant genetic constraints on, increased male mating frequency in C. dalmanni. In order to investigate trade-offs that might constrain male mating frequency under natural conditions we examined correlated responses to artificial selection. We measured accessory gland length, testis length and eyespan after 7 and 14 generations of selection. High line males had significantly larger accessory glands than low line males. No consistent correlated responses to selection were found in testis length or eyespan. Our results suggest that costs associated with the production and maintenance of large accessory glands, although yet to be identified, are likely to be a major constraint on mating frequency in natural populations of C. dalmanni.
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Becker, Penny A; Miller, Philip S; Gunther, Micaela Szykman; Somers, Michael J; Wildt, David E; Maldonado, Jesús E
2012-01-01
The conservation of many fragmented and small populations of endangered African wild dogs (Lycaon pictus) relies on understanding the natural processes affecting genetic diversity, demographics, and future viability. We used extensive behavioural, life-history, and genetic data from reintroduced African wild dogs in South Africa to (1) test for inbreeding avoidance via mate selection and (2) model the potential consequences of avoidance on population persistence. Results suggested that wild dogs avoided mating with kin. Inbreeding was rare in natal packs, after reproductive vacancies, and between sibling cohorts (observed on 0.8%, 12.5%, and 3.8% of occasions, respectively). Only one of the six (16.7%) breeding pairs confirmed as third-order (or closer) kin consisted of animals that were familiar with each other, while no other paired individuals had any prior association. Computer-simulated populations allowed to experience inbreeding had only a 1.6% probability of extinction within 100 years, whereas all populations avoiding incestuous matings became extinct due to the absence of unrelated mates. Populations that avoided mating with first-order relatives became extinct after 63 years compared with persistence of 37 and 19 years for those also prevented from second-order and third-order matings, respectively. Although stronger inbreeding avoidance maintains significantly more genetic variation, our results demonstrate the potentially severe demographic impacts of reduced numbers of suitable mates on the future viability of small, isolated wild dog populations. The rapid rate of population decline suggests that extinction may occur before inbreeding depression is observed.
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Salcedo, A; Kalisz, S; Wright, S I
2014-07-01
Highly selfing species often show reduced effective population sizes and reduced selection efficacy. Whether mixed mating species, which produce both self and outcross progeny, show similar patterns of diversity and selection remains less clear. Examination of patterns of molecular evolution and levels of diversity in species with mixed mating systems can be particularly useful for investigating the relative importance of linked selection and demographic effects on diversity and the efficacy of selection, as the effects of linked selection should be minimal in mixed mating populations, although severe bottlenecks tied to founder events could still be frequent. To begin to address this gap, we assembled and analysed the transcriptomes of individuals from a recently diverged mixed mating sister species pair in the self-compatible genus, Collinsia. The de novo assembly of 52 and 37 Mbp C. concolor and C. parryi transcriptomes resulted in ~40 000 and ~55 000 contigs, respectively, both with an average contig size ~945. We observed a high ratio of shared polymorphisms to fixed differences in the species pair and minimal differences between species in the ratio of synonymous to replacement substitutions or codon usage bias implying comparable effective population sizes throughout species divergence. Our results suggest that differences in effective population size and selection efficacy in mixed mating taxa shortly after their divergence may be minimal and are likely influenced by fluctuating mating systems and population sizes. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.
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Rapid adaptation to mammalian sociality via sexually selected traits
2013-01-01
Background Laboratory studies show that the components of sexual selection (e.g., mate choice and intrasexual competition) can profoundly affect the development and fitness of offspring. Less is known, however, about the total effects of sexual selection on offspring in normal social conditions. Complex social networks, such as dominance hierarchies, regulate the opportunity for mating success, and are often missing from laboratory studies. Social selection is an extended view of sexual selection that incorporates competition during sexual and nonsexual interactions, and predicts complex evolutionary dynamics. Whether social selection improves or constrains offspring fitness is controversial. Results To identify fitness consequences of social selection, wild-derived mice that had bred under laboratory conditions for eight generations were re-introduced to naturalistic competition in enclosures for three consecutive generations (promiscuous line). In parallel, a control lineage bred in cages under random mate assignment (monogamous line). A direct competition experiment using second-generation animals revealed that promiscuous line males had greater reproductive success than monogamous line males (particularly during extra-territorial matings), in spite of higher mortality and equivalent success in social dominance and sperm competition. There were no major female fitness effects (though promiscuous line females had fewer litters than monogamous line females). This result suggested that selection primarily acted upon a sexually attractive male phenotype in the promiscuous line, a hypothesis we confirmed in female odor and mating preference trials. Conclusions We present novel evidence for the strength of sexual selection under normal social conditions, and show rapid male adaptation driven largely by sexual trait expression, with tradeoffs in survivorship and female fecundity. Re-introducing wild-derived mice to competition quickly uncovers sexually selected phenotypes otherwise lost in normal colony breeding. PMID:23577674
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Ronald, Kelly L; Fernández-Juricic, Esteban; Lucas, Jeffrey R
2018-05-16
A common assumption in sexual selection studies is that receivers decode signal information similarly. However, receivers may vary in how they rank signallers if signal perception varies with an individual's sensory configuration. Furthermore, receivers may vary in their weighting of different elements of multimodal signals based on their sensory configuration. This could lead to complex levels of selection on signalling traits. We tested whether multimodal sensory configuration could affect preferences for multimodal signals. We used brown-headed cowbird ( Molothrus ater ) females to examine how auditory sensitivity and auditory filters, which influence auditory spectral and temporal resolution, affect song preferences, and how visual spatial resolution and visual temporal resolution, which influence resolution of a moving visual signal, affect visual display preferences. Our results show that multimodal sensory configuration significantly affects preferences for male displays: females with better auditory temporal resolution preferred songs that were shorter, with lower Wiener entropy, and higher frequency; and females with better visual temporal resolution preferred males with less intense visual displays. Our findings provide new insights into mate-choice decisions and receiver signal processing. Furthermore, our results challenge a long-standing assumption in animal communication which can affect how we address honest signalling, assortative mating and sensory drive. © 2018 The Author(s).
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Poeciliid male mate preference is influenced by female size but not by fecundity
Schlupp, Ingo
2013-01-01
While female mate preference is very well studied, male preference has only recently begun to receive significant attention. Its existence is found in numerous taxa, but empirical research has mostly been limited to a descriptive level and does not fully address the factors influencing its evolution. We attempted to address this issue using preference functions by comparing the strength of male preference for females of different sizes in nine populations of four poeciliid species. Due to environmental constraints (water toxicity and surface versus cave habitat), females from these populations vary in the degree to which their size is correlated to their fecundity. Hence, they vary in how their size signals their quality as mates. Since female size is strongly correlated with fecundity in this subfamily, males were sequentially presented with conspecific females of three different size categories and the strength of their preference for each was measured. Males preferred larger females in all populations, as predicted. However, the degree to which males preferred each size category, as measured by association time, was not correlated with its fecundity. In addition, cave males discriminated against smaller females more than surface males. Assuming that male preference is correlated with female fitness, these results suggest that factors other than fecundity have a strong influence on female fitness in these species. PMID:24010018
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Carrito, Mariana L; Santos, Isabel M; Alho, Laura; Ferreira, Jacqueline; Soares, Sandra C; Bem-Haja, Pedro; Silva, Carlos F; Perrett, David I
2017-03-01
A recent study claimed face skin color as a sexually dimorphic variable that influences attractiveness preferences in mate choice. Thereby, skin color may assume the role of a mate quality signal influencing attractiveness preferences. As body odor is linked to attractiveness, this study aimed to explore whether the odors of men with more masculine facial skin color would be evaluated more positively than odors from less masculine men. Female raters were presented with body odors of 18 men and were asked to rate them in various characteristics. Multilevel modeling revealed that the odors of the donors with more masculine color were rated not only as more attractive, more pleasant, and sexier, but also healthier. This indicates that odor associated with men with more masculine skin color is attractive, just as other sexually dimorphic traits. Furthermore, we found a negative relation between skin color masculinity and perceived odor maleness. Regarding this last finding, a new discussion is introduced with respect to the influence of cognitive stereotypes in odor judgments. Altogether, the study supports the possibility that chemosensory signals may be communicating signs of mate quality associated with masculinity. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Influence of Body Odors and Gender on Perceived Genital Arousal.
Alves-Oliveira, Patrícia; Carvalho, Joana; Ferreira, Jacqueline; Alho, Laura; Nobre, Pedro; Olsson, Mats J; Soares, Sandra C
2018-04-01
Olfaction is often linked to mating behavior in nonhumans. Additionally, studies in mating behavior have shown that women seem to be more affected by odor cues than men. However, the relationship between odor cues and sexual response-specifically, sexual arousal-has not been studied yet. The aim of this study was to evaluate the impact of the exposure to human body odors (from individuals of the opposite gender) on perceived genital arousal, while these were presented concomitantly to sexually explicit video clips. Eighty university students (40 women) rated their perceived genital arousal (perceived degree of erection/genital lubrication) in response to an audiovisual sexual stimulus, while simultaneously exposed to a body odor from an opposite-gender donor or no odor. Participants also rated each odor sample's (body odor and no odor) perceived pleasantness, intensity, and familiarity. Findings indicated that odor condition had an effect on women's (but not men's) perceived genital arousal, with women showing higher levels of perceived genital arousal in the no odor condition. Also, results showed that women rated body odors as less pleasant than no odor. Notwithstanding, the odor ratings do not seem to explain the association between body odor and perceived genital arousal. The current results support the hypothesis that women, rather than men, are sensitive to odors in the context of sexual response. The findings of this study have relevance for the understanding of human sexuality with respect to chemosensory communication.
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Sexual display and mate choice in an energetically costly environment.
Head, Megan L; Wong, Bob B M; Brooks, Robert
2010-12-09
Sexual displays and mate choice often take place under the same set of environmental conditions and, as a consequence, may be exposed to the same set of environmental constraints. Surprisingly, however, very few studies consider the effects of environmental costs on sexual displays and mate choice simultaneously. We conducted an experiment, manipulating water flow in large flume tanks, to examine how an energetically costly environment might affect the sexual display and mate choice behavior of male and female guppies, Poecilia reticulata. We found that male guppies performed fewer sexual displays and became less choosy, with respect to female size, in the presence of a water current compared to those tested in still water. In contrast to males, female responsive to male displays did not differ between the water current treatments and females exhibited no mate preferences with respect to male size or coloration in either treatment. The results of our study underscore the importance of considering the simultaneous effects of environmental costs on the sexual behaviors of both sexes.
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Sperm competition games: the risk model can generate higher sperm allocation to virgin females.
Ball, M A; Parker, G A
2007-03-01
We examine the risk model in sperm competition games for cases where female fertility increases significantly with sperm numbers (sperm limitation). Without sperm competition, sperm allocation increases with sperm limitation. We define 'average risk' as the probability q that females in the population mate twice, and 'perceived risk' as the information males gain about the sperm competition probability with individual females. If males obtain no information from individual females, sperm numbers increase with q unless sperm limitation is high and one of the two competing ejaculates is strongly disfavoured. If males can distinguish between virgin and mated females, greater sperm allocation to virgins is favoured by high sperm limitation, high q, and by the second male's ejaculate being disfavoured. With high sperm limitation, sperm allocation to virgins increases and to mated females decreases with q at high q levels. With perfect information about female mating pattern, sperm allocation (i) to virgins that will mate again exceeds that to mated females and to virgins that will mate only once, (ii) to virgins that mate only once exceeds that for mated females if q is high and there is high second male disadvantage and (iii) to each type of female can decrease with q if sperm limitation is high, although the average allocation increases at least across low q levels. In general, higher sperm allocation to virgins is favoured by: strong disadvantage to the second ejaculate, high sperm limitation, high average risk and increased information (perceived risk). These conditions may apply in a few species, especially spiders.
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Income inequality and educational assortative mating: Evidence from the Luxembourg Income Study.
Monaghan, David
2015-07-01
Though extensive research has explored the prevalence of educational assortative mating, what causes its variation across countries and over time is not well understood. Using data from the Luxembourg Income Study Database, I investigate the hypothesis that assortative mating by income is influenced by income inequality between educational strata. I find that in countries with greater returns to education, the odds of any sort of union that crosses educational boundaries is substantially reduced. However, I do not find substantial evidence of an effect of changes in returns to education on marital sorting within countries. Educational and labor market parity between males and females appear to be negatively related to marital sorting. Copyright © 2015 Elsevier Inc. All rights reserved.
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Blocker, Tomica D.; Ophir, Alexander G.
2012-01-01
Contaminants, like pesticides, polychlorinated biphenyls (PCBs), dioxins and metals, are persistent and ubiquitous and are known to threaten the environment. Traditionally, scientists have considered the direct physiological risks that these contaminants pose. However, scientists have just begun to integrate ethology and toxicology to investigate the effects that contaminants have on behavior. This review considers the potential for contaminant effects on mating behavior. Here we assess the growing body of research concerning disruptions in sexual differentiation, courtship, sexual receptivity, arousal, and mating. We discuss the implications of these disruptions on conservation efforts and highlight the importance of recognizing the potential for environmental stressors to affect behavioral experimentation. More specifically, we consider the negative implications for anthropogenic contaminants to affect the immediate behavior of animals, and their potential to have cascading and/or long-term effects on the behavioral ecology and evolution of populations. Overall, we aim to raise awareness of the confounding influence that contaminants can have, and promote caution when interpreting results where the potential for cryptic affects are possible. PMID:24244068
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On Variation of Polyandry in a Bush-Cricket, Metrioptera roeselii, in Northern Europe
Kaňuch, Peter; Kiehl, Berrit; Low, Matthew; Cassel-Lundhagen, Anna
2013-01-01
Patterns of polyandry in nuptial-gift-giving insects are often explained in terms of sexually antagonistic coevolution. However, the potential influence of environmental constraints and life-history traits on polyandry in these species is still largely unexplored. As an initial step in examining the role of these factors, this study measured the number of matings (spermatodoses per female) of female Roesel's bush-crickets, Metrioptera roeselii Hagenbach (Orthoptera: Tettigoniidae), along a latitudinal gradient in northern Europe (16 sites, 53.89–60.47° N). Females contained between 0 and 5 spermatodoses (mean ± SE: 1.7 ± 0.08; N = 114), with the degree of polyandry generally increasing at higher latitudes (approximately 0.12–0.3 matings per degree of latitude). As expected, female body size also had an influence on polyandry; the number of matings increased from small to moderately large individuals before declining. The field-based results suggested that there were potentially interesting interactions between environment, life-history traits, and patterns of polyandry in nuptial-gift-giving insect species, and these potentially interesting interactions are used to outline future research directions.
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Beauty is in the efficient coding of the beholder.
Renoult, Julien P; Bovet, Jeanne; Raymond, Michel
2016-03-01
Sexual ornaments are often assumed to be indicators of mate quality. Yet it remains poorly known how certain ornaments are chosen before any coevolutionary race makes them indicative. Perceptual biases have been proposed to play this role, but known biases are mostly restricted to a specific taxon, which precludes evaluating their general importance in sexual selection. Here we identify a potentially universal perceptual bias in mate choice. We used an algorithm that models the sparseness of the activity of simple cells in the primary visual cortex (or V1) of humans when coding images of female faces. Sparseness was found positively correlated with attractiveness as rated by men and explained up to 17% of variance in attractiveness. Because V1 is adapted to process signals from natural scenes, in general, not faces specifically, our results indicate that attractiveness for female faces is influenced by a visual bias. Sparseness and more generally efficient neural coding are ubiquitous, occurring in various animals and sensory modalities, suggesting that the influence of efficient coding on mate choice can be widespread in animals.
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Thomas, Gavin H; Freckleton, Robert P; Székely, Tamás
2006-01-01
Phenotypic diversity is not evenly distributed across lineages. Here, we describe and apply a maximum-likelihood phylogenetic comparative method to test for different rates of phenotypic evolution between groups of the avian order Charadriiformes (shorebirds, gulls and alcids) to test the influence of a binary trait (offspring demand; semi-precocial or precocial) on rates of evolution of parental care, mating systems and secondary sexual traits. In semi-precocial species, chicks are reliant on the parents for feeding, but in precocial species the chicks feed themselves. Thus, where the parents are emancipated from feeding the young, we predict that there is an increased potential for brood desertion, and consequently for the divergence of mating systems. In addition, secondary sexual traits are predicted to evolve faster in groups with less demanding young. We found that precocial development not only allows rapid divergence of parental care and mating behaviours, but also promotes the rapid diversification of secondary sexual characters, most notably sexual size dimorphism (SSD) in body mass. Thus, less demanding offspring appear to facilitate rapid evolution of breeding systems and some sexually selected traits. PMID:16769632
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Thomas, Gavin H; Freckleton, Robert P; Székely, Tamás
2006-07-07
Phenotypic diversity is not evenly distributed across lineages. Here, we describe and apply a maximum-likelihood phylogenetic comparative method to test for different rates of phenotypic evolution between groups of the avian order Charadriiformes (shorebirds, gulls and alcids) to test the influence of a binary trait (offspring demand; semi-precocial or precocial) on rates of evolution of parental care, mating systems and secondary sexual traits. In semi-precocial species, chicks are reliant on the parents for feeding, but in precocial species the chicks feed themselves. Thus, where the parents are emancipated from feeding the young, we predict that there is an increased potential for brood desertion, and consequently for the divergence of mating systems. In addition, secondary sexual traits are predicted to evolve faster in groups with less demanding young. We found that precocial development not only allows rapid divergence of parental care and mating behaviours, but also promotes the rapid diversification of secondary sexual characters, most notably sexual size dimorphism (SSD) in body mass. Thus, less demanding offspring appear to facilitate rapid evolution of breeding systems and some sexually selected traits.
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Keegan, Richard; Middleton, Geoff; Henderson, Hannah; Girling, Mica
2016-05-26
There is a lack of understanding of work aged adults' (30-60 years old) perspectives on the motivation of physical activity versus sedentariness. This study aims to: (1) identify which socio-environmental factors motivate physical activity and/or sedentary behavior, in adults aged 30-60 years; and (2) explore how these motivators interact and combine. Fifteen work-aged adults who, were able to engage in physical activity (Mean age = 43.9 years; SD 9.6, range 31-59), participated in semi-structured interviews. Inductive content analysis was used to generate an inventory of socio-environmental factors and their specific influences on motivation towards physical activity or sedentariness. Key socio-environmental agents found to influence motivation included: Spouse/partner, parents, children, siblings, whole family, grandchildren, friends, work-mates, neighbors, strangers, team-mates and class-mates, instructors, health care professionals, employers, gyms and health companies, governments, media and social media, cultural norms, and the physical environment. Mechanisms fell into five broad themes of socio-environmental motivation for both physical activity and sedentariness: (1) competence and progress; (2) informational influences, (3) emotional influences, (4) pragmatics and logistics, and (5) relationships. Similar socio-environmental factors were frequently reported as able to motivate both activity and sedentariness. Likewise, individual categories of influence could also motivate both behaviors, depending on context. The findings of this paper 'unpack' theoretical concepts into specific and targeted behavioral recommendations. The data suggested no simple solutions for promoting physical activity or reducing sedentariness, but rather complex and interacting systems surrounding work-aged adults. Findings also suggest that health professionals should be encouraged to support adults' health by examining the socio-environmental motivational influences, or 'motivational atmosphere'.
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Mate fidelity and breeding site tenacity in a monogamous sandpiper, the black turnstone
Handel, Colleen M.; Gill, Robert E.
2000-01-01
We examined the relationship between mate fidelity and breeding site tenacity during a 5-year study of the black turnstone, Arenaria melanocephala, a socially monogamous sandpiper breeding in subarctic Alaska. We tested the predictions of several hypotheses regarding the incidence of divorce and the benefits of fidelity to mate and breeding site. Interannual return rates to the breeding grounds (88% for males, 79% for females) were among the highest yet recorded for any scolopacid sandpiper, and 88% of returning birds nested on their previous year's territory. The annual divorce rate was only 11%, and mate fidelity was significantly linked to fidelity to territory but independent of sex and year. Males arrived in spring significantly earlier than their mates and interannual fidelity was influenced by the relative timing of arrival of pair members. Reunited pairs had significantly higher fledging success than new pairs formed after death or divorce. The incidence of divorce was unrelated to reproductive success the previous year, although birds nested significantly further away after failure than after a successful nesting attempt. Sightings of marked individuals suggested that members of pairs do not winter together, and breeding site tenacity provides a mechanism through which pair members can reunite. We reject the 'incompatibility' hypothesis for divorce in turnstones, and our data contradict predictions of the 'better option' hypothesis. Alternatively, we propose the 'bet-hedging' hypothesis to explain the occurrence of divorce, which transpires when an individual pairs with a new mate to avoid the cost of waiting for a previous mate to return. Such costs can include remaining unmated, if the former mate has died, or experiencing lower reproductive success because of delayed breeding.
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Fitness cost of pheromone production in signaling female moths.
Harari, Ally R; Zahavi, Tirtza; Thiéry, Denis
2011-06-01
A secondary sexual character may act as an honest signal of the quality of the individual if the trait bears a cost and if its expression is phenotypically condition dependent. The cost of increasing the trait should be tolerable for individuals in good condition but not for those in a poor condition. The trait thus provides an honest signal of quality that enables the receiver to choose higher quality mates. Evidence for sex pheromones, which play a major role in shaping sexual evolution, inflicting a signaling cost is scarce. Here, we demonstrate that the amount of the major component of the pheromone in glands of Lobesia botrana (Lepidoptera) females at signaling time was significantly greater in large than in small females, that male moths preferred larger females as mates when responding to volatile signals, and small virgin females, but not large ones, exposed to conspecific pheromone, produced, when mated, significantly fewer eggs than nonexposed females. The latter indicates a condition-dependent cost of signaling. These results are in accordance with the predictions of condition-dependent honest signals. We therefore suggest that female signaling for males using sex pheromones bears a cost and thus calling may serve as honest advertisement for female quality. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
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The evolution of monogamy in response to partner scarcity
Schacht, Ryan; Bell, Adrian V.
2016-01-01
The evolution of monogamy and paternal care in humans is often argued to have resulted from the needs of our expensive offspring. Recent research challenges this claim, however, contending that promiscuous male competitors and the risk of cuckoldry limit the scope for the evolution of male investment. So how did monogamy first evolve? Links between mating strategies and partner availability may offer resolution. While studies of sex roles commonly assume that optimal mating rates for males are higher, fitness payoffs to monogamy and the maintenance of a single partner can be greater when partners are rare. Thus, partner availability is increasingly recognized as a key variable structuring mating behavior. To apply these recent insights to human evolution, we model three male strategies – multiple mating, mate guarding and paternal care – in response to partner availability. Under assumed ancestral human conditions, we find that male mate guarding, rather than paternal care, drives the evolution of monogamy, as it secures a partner and ensures paternity certainty in the face of more promiscuous competitors. Accordingly, we argue that while paternal investment may be common across human societies, current patterns should not be confused with the reason pairing first evolved. PMID:27600189
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The evolution of monogamy in response to partner scarcity.
Schacht, Ryan; Bell, Adrian V
2016-09-07
The evolution of monogamy and paternal care in humans is often argued to have resulted from the needs of our expensive offspring. Recent research challenges this claim, however, contending that promiscuous male competitors and the risk of cuckoldry limit the scope for the evolution of male investment. So how did monogamy first evolve? Links between mating strategies and partner availability may offer resolution. While studies of sex roles commonly assume that optimal mating rates for males are higher, fitness payoffs to monogamy and the maintenance of a single partner can be greater when partners are rare. Thus, partner availability is increasingly recognized as a key variable structuring mating behavior. To apply these recent insights to human evolution, we model three male strategies - multiple mating, mate guarding and paternal care - in response to partner availability. Under assumed ancestral human conditions, we find that male mate guarding, rather than paternal care, drives the evolution of monogamy, as it secures a partner and ensures paternity certainty in the face of more promiscuous competitors. Accordingly, we argue that while paternal investment may be common across human societies, current patterns should not be confused with the reason pairing first evolved.
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Hernandez-Jimenez, Armando; Rios-Cardenas, Oscar
2017-12-06
There is extensive morphological variation of male genitalia across animals with internal fertilization, even among closely related species. Most studies attempting to explain this extraordinary diversity have focused on processes that occur post-copula (e.g. sperm competition, cryptic female choice). Only a few studies have focused on the pre-copula process of female preference. In addition, the extent to which this variation could be associated with the use of different reproductive tactics has yet to be explored. Here, we show that female preference for male genitalia length in two livebearing fishes depends on the type of reproductive tactic of the males being evaluated as well as the body condition of the female. In a species where all males coax females to acquire matings (courters), females preferred males with short genitalia. In a species with genetically influenced alternative reproductive tactics (courter males that only court and produce courter sons, sneaker males that use the coercive tactic of sneak chase and produce sneaker sons), female preference depended on an interaction between male tactic and female condition: females in good condition preferred courter males with short genitalia, and sneaker males with long genitalia. Our results suggest that female preference for male traits favourable to their sons may be an important factor contributing to the diversification of male genitalia. Despite the contrasting selection for genitalia length that our female preference tests suggest, we found no significant differences in genitalia length between coaxing (courters) and coercive (sneakers) males. Our study represents a starting point to more clearly understand the role of alternative reproductive tactics and variation in female mate preference in the evolution of male genitalia. © 2017 The Author(s).
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Computational mate choice: theory and empirical evidence.
Castellano, Sergio; Cadeddu, Giorgia; Cermelli, Paolo
2012-06-01
The present review is based on the thesis that mate choice results from information-processing mechanisms governed by computational rules and that, to understand how females choose their mates, we should identify which are the sources of information and how they are used to make decisions. We describe mate choice as a three-step computational process and for each step we present theories and review empirical evidence. The first step is a perceptual process. It describes the acquisition of evidence, that is, how females use multiple cues and signals to assign an attractiveness value to prospective mates (the preference function hypothesis). The second step is a decisional process. It describes the construction of the decision variable (DV), which integrates evidence (private information by direct assessment), priors (public information), and value (perceived utility) of prospective mates into a quantity that is used by a decision rule (DR) to produce a choice. We make the assumption that females are optimal Bayesian decision makers and we derive a formal model of DV that can explain the effects of preference functions, mate copying, social context, and females' state and condition on the patterns of mate choice. The third step of mating decision is a deliberative process that depends on the DRs. We identify two main categories of DRs (absolute and comparative rules), and review the normative models of mate sampling tactics associated to them. We highlight the limits of the normative approach and present a class of computational models (sequential-sampling models) that are based on the assumption that DVs accumulate noisy evidence over time until a decision threshold is reached. These models force us to rethink the dichotomy between comparative and absolute decision rules, between discrimination and recognition, and even between rational and irrational choice. Since they have a robust biological basis, we think they may represent a useful theoretical tool for behavioural ecologist interested in integrating proximate and ultimate causes of mate choice. Copyright © 2012 Elsevier B.V. All rights reserved.
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The genetic correlation between height and IQ: shared genes or assortative mating?
Keller, Matthew C; Garver-Apgar, Christine E; Wright, Margaret J; Martin, Nicholas G; Corley, Robin P; Stallings, Michael C; Hewitt, John K; Zietsch, Brendan P
2013-04-01
Traits that are attractive to the opposite sex are often positively correlated when scaled such that scores increase with attractiveness, and this correlation typically has a genetic component. Such traits can be genetically correlated due to genes that affect both traits ("pleiotropy") and/or because assortative mating causes statistical correlations to develop between selected alleles across the traits ("gametic phase disequilibrium"). In this study, we modeled the covariation between monozygotic and dizygotic twins, their siblings, and their parents (total N = 7,905) to elucidate the nature of the correlation between two potentially sexually selected traits in humans: height and IQ. Unlike previous designs used to investigate the nature of the height-IQ correlation, the present design accounts for the effects of assortative mating and provides much less biased estimates of additive genetic, non-additive genetic, and shared environmental influences. Both traits were highly heritable, although there was greater evidence for non-additive genetic effects in males. After accounting for assortative mating, the correlation between height and IQ was found to be almost entirely genetic in nature. Model fits indicate that both pleiotropy and assortative mating contribute significantly and about equally to this genetic correlation.
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Mossotti, Regina H; Baskir, Eli A; Kozlowski, Corinne P; Franklin, Ashley D; Feldhamer, George A; Asa, Cheryl S
2018-06-13
Understanding the factors used by female cheetahs (Acinonyx jubatus) to make mate choice decisions could benefit zoo breeding programs, which currently assign mates based primarily on genetic distance. Because transporting animals between institutions is costly and can be stressful, females are often limited in the number of males available for mating. One solution would be to determine if an easily transported substance could be used to gauge interest by a female to a potential mate. Here, we investigate female interest in urine samples from males of different genetic distances. Twelve females at five institutions were offered scents from 17 males of varying genetic relatedness in a pair-wise choice paradigm. Behavioral responses of the females were recorded to determine preference. Results showed that females spent more time sniffing and in proximity to scents from the most distantly related males, but female response was not influenced by male urine testosterone concentration, female parity, age, or estrous cycling. Further research will be necessary to determine whether a female's interest in male urine translates to mate preference and acceptance before this technique can be applied to zoo breeding programs. © 2018 Wiley Periodicals, Inc.
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The Adaptive Function of Masturbation in a Promiscuous African Ground Squirrel
Waterman, Jane M.
2010-01-01
Background Studies of animal mating systems increasingly emphasize female multiple mating and cryptic sexual selection, particularly sperm competition. Males under intense sperm competition may manipulate sperm quantity and quality through masturbation, which could waste sperm and decrease fertility. I examined the factors influencing masturbation by male Cape ground squirrels (Xerus inauris) in light of a number of functional hypotheses. Methodology Observational data on a marked population of squirrels were collected in east-central Namibia using scan and all-occurrences sampling. Findings Masturbation was far more frequent on days of female oestrus and mostly occurred after copulation. Masturbation rates were higher in dominant males, which copulate more, than in subordinates and increased with number of mates a female accepts. Conclusions These results suggest that masturbation in this species was not a response to sperm competition nor a sexual outlet by subordinates that did not copulate. Instead masturbation could function as a form of genital grooming. Female Cape ground squirrels mate with up to 10 males in a 3-hr oestrus, and by masturbating after copulation males could reduce the chance of infection. Sexually transmitted infections (STIs) can profoundly affect fertility, and their consequences for mating strategies need to be examined more fully. PMID:20927404
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The adaptive function of masturbation in a promiscuous African ground squirrel.
Waterman, Jane M
2010-09-28
Studies of animal mating systems increasingly emphasize female multiple mating and cryptic sexual selection, particularly sperm competition. Males under intense sperm competition may manipulate sperm quantity and quality through masturbation, which could waste sperm and decrease fertility. I examined the factors influencing masturbation by male Cape ground squirrels (Xerus inauris) in light of a number of functional hypotheses. Observational data on a marked population of squirrels were collected in east-central Namibia using scan and all-occurrences sampling. Masturbation was far more frequent on days of female oestrus and mostly occurred after copulation. Masturbation rates were higher in dominant males, which copulate more, than in subordinates and increased with number of mates a female accepts. These results suggest that masturbation in this species was not a response to sperm competition nor a sexual outlet by subordinates that did not copulate. Instead masturbation could function as a form of genital grooming. Female Cape ground squirrels mate with up to 10 males in a 3-hr oestrus, and by masturbating after copulation males could reduce the chance of infection. Sexually transmitted infections (STIs) can profoundly affect fertility, and their consequences for mating strategies need to be examined more fully.
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Heidinger, Ina Monika Margret; Meixner, Marina Doris; Berg, Stefan; Büchler, Ralph
2014-01-01
We used radio-frequency identification (RFID) to record the duration and frequency of nuptial flights of honey bee queens (Apis mellifera carnica) at two mainland mating apiaries. We investigated the effect of a number of factors on flight duration and frequency: mating apiary, number of drone colonies, queen’s age and temperature. We found significant differences between the two locations concerning the number of flights on the first three days. We also observed an effect of the ambient temperature, with queens flying less often but longer at high temperatures compared to lower temperatures. Increasing the number of drone colonies from 33 to 80 colonies had no effect on the duration or on the frequency of nuptial flights. Since our results agree well with the results of previous studies, we suggest RFID as an appropriate tool to investigate the mating behavior of honey bee queens. PMID:26462822
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Mating in the Closest Living Relatives of Animals Is Induced by a Bacterial Chondroitinase.
Woznica, Arielle; Gerdt, Joseph P; Hulett, Ryan E; Clardy, Jon; King, Nicole
2017-09-07
We serendipitously discovered that the marine bacterium Vibrio fischeri induces sexual reproduction in one of the closest living relatives of animals, the choanoflagellate Salpingoeca rosetta. Although bacteria influence everything from nutrition and metabolism to cell biology and development in eukaryotes, bacterial regulation of eukaryotic mating was unexpected. Here, we show that a single V. fischeri protein, the previously uncharacterized EroS, fully recapitulates the aphrodisiac-like activity of live V. fischeri. EroS is a chondroitin lyase; although its substrate, chondroitin sulfate, was previously thought to be an animal synapomorphy, we demonstrate that S. rosetta produces chondroitin sulfate and thus extend the ancestry of this important glycosaminoglycan to the premetazoan era. Finally, we show that V. fischeri, purified EroS, and other bacterial chondroitin lyases induce S. rosetta mating at environmentally relevant concentrations, suggesting that bacteria likely regulate choanoflagellate mating in nature. Copyright © 2017 Elsevier Inc. All rights reserved.
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Zhang, Jibin; Huang, Ling; He, Jin; Tomberlin, Jeffery K.; Li, Jianhong; Lei, Chaoliang; Sun, Ming; Liu, Ziduo; Yu, Ziniu
2010-01-01
Current methods for mass-rearing black soldier flies, Hermetia illucens (L.) (Diptera: Stratiomyidae), in the laboratory are dependent on sunlight. Quartz-iodine lamps and rare earth lamps were examined as artificial light sources for stimulating H. illucens to mate and lay eggs. Sunlight was used as the control. Adults in the quartz-iodine lamp treatment had a mating rate of 61% of those in the sunlight control. No mating occurred when the rare earth lamp was used as a substitute. Egg hatch for the quartz-iodine lamp and sunlight treatments occurred in approximately 4 days, and the hatch rate was similar between these two treatments. Larval and pupal development under these treatments required approximately 18 and 15 days at 28°° C, respectively. Development of methods for mass rearing of H. illucens using artificial light will enable production of this fly throughout the year without investing in greenhouse space or requiring sunlight. PMID:21268697
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Davis, A Gabriell; Leary, Christopher J
2015-03-01
Mate selection can be stressful; time spent searching for mates can increase predation risk and/or decrease food consumption, resulting in elevated stress hormone levels. Both high predation risk and low food availability are often associated with increased variation in mate choice by females, but it is not clear whether stress hormone levels contribute to such variation in female behavior. We examined how the stress hormone corticosterone (CORT) affects female preferences for acoustic signals in the green treefrog, Hyla cinerea. Specifically, we assessed whether CORT administration affects female preferences for call rate - an acoustic feature that is typically under directional selection via mate choice by females in most anurans and other species that communicate using acoustic signals. Using a dual speaker playback paradigm, we show that females that were administered higher doses of CORT were less likely to choose male advertisement calls broadcast at high rates. Neither CORT dose nor level was related to the latency of female phonotactic responses, suggesting that elevated CORT does not influence the motivation to mate. Results were also not related to circulating sex steroids (i.e., progesterone, androgens or estradiol) that have traditionally been the focus of studies examining the hormonal basis for variation in female mate choice. Our results thus indicate that elevated CORT levels decrease the strength of female preferences for acoustic signals. Copyright © 2015 Elsevier Inc. All rights reserved.
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Female Genitalia Concealment Promotes Intimate Male Courtship in a Water Strider
Han, Chang S.; Jablonski, Piotr G.
2009-01-01
Violent coercive mating initiation is typical for animals with sexual conflict over mating. In these species, the coevolutionary arms-race between female defenses against coercive mating and male counter-adaptations for increased mating success leads to coevolutionary chases of male and female traits that influence the mating. It has been controversial whether one of the sexes can evolve traits that allow them to “win” this arms race. Here, we use morphological analysis (traditional and scanning electron micrographs), laboratory experiments and comparative methods to show how females of a species characterized by typical coercive mating initiation appear to “win” a particular stage of the sexual conflict by evolving morphology to hide their genitalia from direct, forceful access by males. In an apparent response to the female morphological adaptation, males of this species added to their typically violent coercive mounting of the female new post-mounting, pre-copulatory courtship signals produced by tapping the water's surface with the mid-legs. These courtship signals are intimate in the sense that they are aimed at the female, on whom the male is already mounted. Females respond to the signals by exposing their hidden genitalia for copulatory intromission. Our results indicate that the apparent victory of coevolutionary arms race by one sex in terms of morphology may trigger evolution of a behavioral phenotype in the opposite sex. PMID:19516886
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Strandh, Maria; Westerdahl, Helena; Pontarp, Mikael; Canbäck, Björn; Dubois, Marie-Pierre; Miquel, Christian; Taberlet, Pierre; Bonadonna, Francesco
2012-01-01
Mate choice for major histocompatibility complex (MHC) compatibility has been found in several taxa, although rarely in birds. MHC is a crucial component in adaptive immunity and by choosing an MHC-dissimilar partner, heterozygosity and potentially broad pathogen resistance is maximized in the offspring. The MHC genotype influences odour cues and preferences in mammals and fish and hence olfactory-based mate choice can occur. We tested whether blue petrels, Halobaena caerulea, choose partners based on MHC compatibility. This bird is long-lived, monogamous and can discriminate between individual odours using olfaction, which makes it exceptionally well suited for this analysis. We screened MHC class I and II B alleles in blue petrels using 454-pyrosequencing and quantified the phylogenetic, functional and allele-sharing similarity between individuals. Partners were functionally more dissimilar at the MHC class II B loci than expected from random mating (p = 0.033), whereas there was no such difference at the MHC class I loci. Phylogenetic and non-sequence-based MHC allele-sharing measures detected no MHC dissimilarity between partners for either MHC class I or II B. Our study provides evidence of mate choice for MHC compatibility in a bird with a high dependency on odour cues, suggesting that MHC odour-mediated mate choice occurs in birds. PMID:22951737
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Unexpected Strong Polygyny in the Brown-Throated Three-Toed Sloth
Pauli, Jonathan N.; Peery, M. Zachariah
2012-01-01
Promiscuous mating strategies are much more common than previously appreciated. So much so, that several authors have proposed that promiscuity is the “rule” rather than the exception in vertebrate mating systems. Decreasing species mobility and increasing habitat fragmentation have both been suggested to reduce the “polygyny potential” of the environment and promote other mating strategies like promiscuity in females. We explored the social and genetic mating system for one of the most sedentary extant mammals, the brown-throated three-toed sloth (Bradypus variegatus), within a highly fragmented Neotropical habitat. Surprisingly, we found that three-toed sloths were strongly polygynous, with males excluding male competitors from their core ranges, and exhibiting strong reproductive skew. Indeed, only 25% of all resident adult males sired offspring and one individual sired half of all sampled juveniles. Paradoxically, a sedentary life-history strategy seems to facilitate polygyny in fragmented landscapes because multiple females can persist within small patches of habitat, and be monopolized by a single male. Our work demonstrates that strong polygyny can arise in systems in which the polygyny potential should be extremely low, and other strategies, including promiscuity, would be favoured. Mating systems can be influenced by a multitude of factor and are dynamic, varying among taxa, over time, and across habitats; consequently, mating systems remain difficult to predict based on general ecological principles. PMID:23284687
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Do Your School Mates Influence How Long You Game? Evidence from the U.S.
Amialchuk, Aliaksandr; Kotalik, Ales
2016-01-01
The goal of this paper is to estimate peer influence in video gaming time among adolescents. Using a nationally representative sample of the U.S. school-aged adolescents in 2009–2010, we estimate a structural model that accounts for the potential biases in the estimate of the peer effect. Our peer group is exogenously assigned and includes one year older adolescents in the same school grade as the respondent. The peer measure is based on peers’ own reports of video gaming time. We find that an additional one hour of playing video games per week by older grade-mates results in .47 hours increase in video gaming time by male responders. We do not find significant peer effect among female responders. Effective policies aimed at influencing the time that adolescents spend video gaming should take these findings into account. PMID:27494337
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Social influences on the estrous cycle of the captive sun bear (Helarctos Malayanus).
Frederick, Cheryl; Hunt, Kathleen; Kyes, Randall; Collins, Darin; Durrant, Barbara; Ha, James; Wasser, Samuel K
2013-01-01
We examined the potential influences of existing social housing arrangements on captive sun bear female reproductive cycling. Three social conditions were studied: 1.2, 1.1, and 0.2. Fecal hormone metabolites of total estrogens, progestins and glucocorticoids were compared between the three social conditions and were analyzed along with vaginal cytology data in individuals that experienced a change in social condition. Behavioral data were collected on females in each of the social conditions and summarized into agonistic, affiliative and sexual categories. Results indicated that sun bears are spontaneous ovulators, but that the presence of a male does influence hormone metabolite concentrations and cytological profiles. Male presence was also associated with a greater proportion of females cycling. In most female pairs, only one female cycled, typically the younger, subordinate female. The presence of a second female appeared to have a suppressive influence on both cycling and mating behavior. Agonistic behavior and associated stress may be a mechanism for lowering progesterone. In contrast, high estrogen levels were associated with low levels of agonistic interactions; thus, reproductive cycle monitoring could facilitate social introductions with either sex. Females in 1.2 social groupings had significantly higher GC metabolite concentrations and agonistic behavior, suggesting that 1.2 social groupings may not be advisable for captive breeding programs. Data from the North American historical captive population indicate that at most 32% of all sun bear pairs and only 18.5% of females have successfully reproduced. Implications of these social and reproductive patterns for captive management are discussed. © 2013 Wiley Periodicals, Inc.
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Model of Exploratory Search for Mating Partners by Fission Yeast
NASA Astrophysics Data System (ADS)
Hurwitz, Daniel; Bendezu, Felipe; Martin, Sophie; Vavylonis, Dimitrios
2014-03-01
During conditions of nitrogen starvation, the model eukaryote S. pombe (fission yeast) undergoes sexual sporulation. Because fission yeast are non-motile, contact between opposite mating types during spore formation is accomplished by polarizing growth, via the Rho GTP-ase Cdc42, in each mating type towards the selected mate, a process known as shmooing. Recent findings showed that cells pick one of their neighboring compatible mates by randomizing the position of the Cdc42 complex about the cell membrane, such that the complex is stabilized near areas of high concentration of the opposite mating type pheromone. We developed Monte Carlo simulations to model partner finding in populations of mating cells and in small cell clusters. We assume that pheromones are secreted at the site of Cdc42 accumulation and that the Cdc42 dwell time increases in response to increasing pheromone concentration. We measured the number of cells that succeed in successful reciprocal pairing, the number of cells that were unable to find a partner, and the number of cells that picked a partner already engaged with another cell. For optimal cell pairing, we find the pheromone concentration decay length is around 1 micron, of order the cell size. We show that non-linear response of Cdc42 dwell time to pheromone concentration improves the number of successful pairs for a given spatial cell distribution. We discuss how these results compare to non-exploratory pairing mechanisms.
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Isolation of pheromone precursor genes of Magnaporthe grisea.
Shen, W C; Bobrowicz, P; Ebbole, D J
1999-01-01
In heterothallic ascomycetes one mating partner serves as the source of female tissue and is fertilized with spermatia from a partner of the opposite mating type. The role of pheromone signaling in mating is thought to involve recognition of cells of the opposite mating type. We have isolated two putative pheromone precursor genes of Magnaporthe grisea. The genes are present in both mating types of the fungus but they are expressed in a mating type-specific manner. The MF1-1 gene, expressed in Mat1-1 strains, is predicted to encode a 26-amino-acid polypeptide that is processed to produce a lipopeptide pheromone. The MF2-1 gene, expressed in Mat1-2 strains, is predicted to encode a precursor polypeptide that is processed by a Kex2-like protease to yield a pheromone with striking similarity to the predicted pheromone sequence of a close relative, Cryphonectria parasitica. Expression of the M. grisea putative pheromone precursor genes was observed under defined nutritional conditions and in field isolates. This suggests that the requirement for complex media for mating and the poor fertility of field isolates may not be due to limitation of pheromone precursor gene expression. Detection of putative pheromone precursor gene mRNA in conidia suggests that pheromones may be important for the fertility of conidia acting as spermatia. Copyright 1999 Academic Press.
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Penley, McKenna J; Ha, Giang T; Morran, Levi T
2017-01-01
Parasites can impose strong selection on hosts. In response, some host populations have adapted via the evolution of defenses that prevent or impede infection by parasites. However, host populations have also evolved life history shifts that maximize host fitness despite infection. Outcrossing and self-fertilization can have contrasting effects on evolutionary trajectories of host populations. While selfing and outcrossing are known to affect the rate at which host populations adapt in response to parasites, these mating systems may also influence the specific traits that underlie adaptation to parasites. Here, we determined the role of evolved host defense versus altered life history,in mixed mating (selfing and outcrossing) and obligately outcrossing C. elegans host populations after experimental evolution with the bacterial parasite, S. marcescens. Similar to previous studies, we found that both mixed mating and obligately outcrossing host populations adapted to S. marcescens exposure, and that the obligately outcrossing populations exhibited the greatest rates of adaptation. Regardless of the host population mating system, exposure to parasites did not significantly alter reproductive timing or total fecundity over the course of experimental evolution. However, both mixed mating and obligately outcrossing host populations exhibited significantly reduced mortality rates in the presence of the parasite after experimental evolution. Therefore, adaptation in both the mixed mating and obligately outcrossing populations was driven, at least in part, by the evolution of increased host defense and not changes in host life history. Thus, the host mating system altered the rate of adaptation, but not the nature of adaptive change in the host populations.
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Penley, McKenna J.; Ha, Giang T.; Morran, Levi T.
2017-01-01
Parasites can impose strong selection on hosts. In response, some host populations have adapted via the evolution of defenses that prevent or impede infection by parasites. However, host populations have also evolved life history shifts that maximize host fitness despite infection. Outcrossing and self-fertilization can have contrasting effects on evolutionary trajectories of host populations. While selfing and outcrossing are known to affect the rate at which host populations adapt in response to parasites, these mating systems may also influence the specific traits that underlie adaptation to parasites. Here, we determined the role of evolved host defense versus altered life history,in mixed mating (selfing and outcrossing) and obligately outcrossing C. elegans host populations after experimental evolution with the bacterial parasite, S. marcescens. Similar to previous studies, we found that both mixed mating and obligately outcrossing host populations adapted to S. marcescens exposure, and that the obligately outcrossing populations exhibited the greatest rates of adaptation. Regardless of the host population mating system, exposure to parasites did not significantly alter reproductive timing or total fecundity over the course of experimental evolution. However, both mixed mating and obligately outcrossing host populations exhibited significantly reduced mortality rates in the presence of the parasite after experimental evolution. Therefore, adaptation in both the mixed mating and obligately outcrossing populations was driven, at least in part, by the evolution of increased host defense and not changes in host life history. Thus, the host mating system altered the rate of adaptation, but not the nature of adaptive change in the host populations. PMID:28792961
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van Schaik, J; Kerth, G
2017-02-01
For non-mobile parasites living on social hosts, infection dynamics are strongly influenced by host life history and social system. We explore the impact of host social systems on parasite population dynamics by comparing the infection intensity and transmission opportunities of three mite species of the genus Spinturnix across their three European bat hosts (Myotis daubentonii, Myotis myotis, Myotis nattereri) during the bats' autumn mating season. Mites mainly reproduce in host maternity colonies in summer, but as these colonies are closed, opportunities for inter-colony transmission are limited to host interactions during the autumn mating season. The three investigated hosts differ considerably in their social system, most notably in maternity colony size, mating system, and degree of male summer aggregation. We observed marked differences in parasite infection during the autumn mating period between the species, closely mirroring the predictions made based on the social systems of the hosts. Increased host aggregation sizes in summer yielded higher overall parasite prevalence and intensity, both in male and female hosts. Moreover, parasite levels in male hosts differentially increased throughout the autumn mating season in concordance with the degree of contact with female hosts afforded by the different mating systems of the hosts. Critically, the observed host-specific differences have important consequences for parasite population structure and will thus affect the coevolutionary dynamics between the interacting species. Therefore, in order to accurately characterize host-parasite dynamics in hosts with complex social systems, a holistic approach that investigates parasite infection and transmission across all periods is warranted.
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Becker, Penny A.; Miller, Philip S.; Gunther, Micaela Szykman; Somers, Michael J.; Wildt, David E.; Maldonado, Jesús E.
2012-01-01
The conservation of many fragmented and small populations of endangered African wild dogs (Lycaon pictus) relies on understanding the natural processes affecting genetic diversity, demographics, and future viability. We used extensive behavioural, life-history, and genetic data from reintroduced African wild dogs in South Africa to (1) test for inbreeding avoidance via mate selection and (2) model the potential consequences of avoidance on population persistence. Results suggested that wild dogs avoided mating with kin. Inbreeding was rare in natal packs, after reproductive vacancies, and between sibling cohorts (observed on 0.8%, 12.5%, and 3.8% of occasions, respectively). Only one of the six (16.7%) breeding pairs confirmed as third-order (or closer) kin consisted of animals that were familiar with each other, while no other paired individuals had any prior association. Computer-simulated populations allowed to experience inbreeding had only a 1.6% probability of extinction within 100 years, whereas all populations avoiding incestuous matings became extinct due to the absence of unrelated mates. Populations that avoided mating with first-order relatives became extinct after 63 years compared with persistence of 37 and 19 years for those also prevented from second-order and third-order matings, respectively. Although stronger inbreeding avoidance maintains significantly more genetic variation, our results demonstrate the potentially severe demographic impacts of reduced numbers of suitable mates on the future viability of small, isolated wild dog populations. The rapid rate of population decline suggests that extinction may occur before inbreeding depression is observed. PMID:22615933
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Kaburu, Stefano S K; Newton-Fisher, Nicholas E
2015-06-01
Across taxa, males employ a variety of mating strategies, including sexual coercion and the provision, or trading, of resources. Biological market theory (BMT) predicts that trading of commodities for mating opportunities should exist only when males cannot monopolize access to females and/or obtain mating by force, in situations where power differentials between males are low; both coercion and trading have been reported for chimpanzees ( Pan troglodytes ). Here, we investigate whether the choice of strategy depends on the variation in male power differentials, using data from two wild communities of East African chimpanzees ( Pan troglodytes schweinfurthii ): the structurally despotic Sonso community (Budongo, Uganda) and the structurally egalitarian M-group (Mahale, Tanzania). We found evidence of sexual coercion by male Sonso chimpanzees, and of trading-of grooming for mating-by M-group males; females traded sex for neither meat nor protection from male aggression. Our results suggest that the despotism-egalitarian axis influences strategy choice: male chimpanzees appear to pursue sexual coercion when power differentials are large and trading when power differentials are small and coercion consequently ineffective. Our findings demonstrate that trading and coercive strategies are not restricted to particular chimpanzee subspecies; instead, their occurrence is consistent with BMT predictions. Our study raises interesting, and as yet unanswered, questions regarding female chimpanzees' willingness to trade sex for grooming, if doing so represents a compromise to their fundamentally promiscuous mating strategy. It highlights the importance of within-species cross-group comparisons and the need for further study of the relationship between mating strategy and dominance steepness.
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REINFORCEMENT OF STICKLEBACK MATE PREFERENCES: SYMPATRY BREEDS CONTEMPT.
Rundle, Howard D; Schluter, Dolph
1998-02-01
Detailed studies of reproductive isolation and how it varies among populations can provide valuable insight into the mechanisms of speciation. Here we investigate how the strength of premating isolation varies between sympatric and allopatric populations of threespine sticklebacks to test a prediction of the hypothesis of reinforcement: that interspecific mate discrimination should be stronger in sympatry than in allopatry. In conducting such tests, it is important to control for ecological character displacement between sympatric species because ecological character divergence may strengthen prezygotic isolation as a by-product. We control for ecological character displacement by comparing mate preferences of females from a sympatric population (benthics) with mate preferences of females from two allopatric populations that most closely resemble the sympatric benthic females in ecology and morphology. No-choice mating trials indicate that sympatric benthic females mate less readily with heterospecific (limnetic) than conspecific (benthic) males, whereas two different populations of allopatric females resembling benthics show no such discrimination. These differences demonstrate reproductive character displacement of benthic female mate choice. Previous studies have established that hybridization between sympatric species occurred in the past in the wild and that hybrid offspring have lower fitness than either parental species, thus providing conditions under which natural selection would favor individuals that do not hybridize. Results are therefore consistent with the hypothesis that female mate preferences have evolved as a response to reduced hybrid fitness (reinforcement), although direct effects of sympatry or a biased extinction process could also produce the pattern. Males of the other sympatric species (limnetics) showed a preference for smaller females, in contrast to the inferred ancestral preference for larger females, suggesting reproductive character displacement of limnetic male mate preferences as well. © 1998 The Society for the Study of Evolution.
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On the roles of colour and scent in a specialized floral mimicry system
Vereecken, Nicolas J.; Schiestl, Florian P.
2009-01-01
Background and Aims Sexually deceptive orchids achieve cross-pollination by mimicking the mating signals of female insects, generally hymenopterans. This pollination mechanism is often highly specific as it is based primarily on the mimicry of mating signals, especially the female sex pheromones of the targeted pollinator. Like many deceptive orchids, the Mediterranean species Ophrys arachnitiformis shows high levels of floral trait variation, especially in the colour of the perianth, which is either green or white/pinkinsh within populations. The adaptive significance of perianth colour polymorphism and its influence on pollinator visitation rates in sexually deceptive orchids remain obscure. Methods The relative importance of floral scent versus perianth colour in pollinator attraction in this orchid pollinator mimicry system was evaluated by performing floral scent analyses by gas chromatography-mass spectrometry (GC-MS) and behavioural bioassays with the pollinators under natural conditions were performed. Key Results The relative and absolute amounts of behaviourally active compounds are identical in the two colour morphs of O. arachnitiformis. Neither presence/absence nor the colour of the perianth (green versus white) influence attractiveness of the flowers to Colletes cunicularius males, the main pollinator of O. arachnitiformis. Conclusion Chemical signals alone can mediate the interactions in highly specialized mimicry systems. Floral colour polymorphism in O. arachnitiformis is not subjected to selection imposed by C. cunicularius males, and an interplay between different non-adaptive processes may be responsible for the maintenance of floral colour polymorphism both within and among populations. PMID:19692390
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On the roles of colour and scent in a specialized floral mimicry system.
Vereecken, Nicolas J; Schiestl, Florian P
2009-11-01
Sexually deceptive orchids achieve cross-pollination by mimicking the mating signals of female insects, generally hymenopterans. This pollination mechanism is often highly specific as it is based primarily on the mimicry of mating signals, especially the female sex pheromones of the targeted pollinator. Like many deceptive orchids, the Mediterranean species Ophrys arachnitiformis shows high levels of floral trait variation, especially in the colour of the perianth, which is either green or white/pinkinsh within populations. The adaptive significance of perianth colour polymorphism and its influence on pollinator visitation rates in sexually deceptive orchids remain obscure. The relative importance of floral scent versus perianth colour in pollinator attraction in this orchid pollinator mimicry system was evaluated by performing floral scent analyses by gas chromatography-mass spectrometry (GC-MS) and behavioural bioassays with the pollinators under natural conditions were performed. The relative and absolute amounts of behaviourally active compounds are identical in the two colour morphs of O. arachnitiformis. Neither presence/absence nor the colour of the perianth (green versus white) influence attractiveness of the flowers to Colletes cunicularius males, the main pollinator of O. arachnitiformis. Chemical signals alone can mediate the interactions in highly specialized mimicry systems. Floral colour polymorphism in O. arachnitiformis is not subjected to selection imposed by C. cunicularius males, and an interplay between different non-adaptive processes may be responsible for the maintenance of floral colour polymorphism both within and among populations.
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Bauer, Jessica
2016-01-01
Abstract Detecting past experiences with predators of a potential mate informs a female about prevailing ecological threats, in addition to stress-induced phenotypes that may be disseminated to offspring. We examined whether prior exposure of a male rat to a predator (cat) odor influences the attraction of a female toward a male, subsequent mother–infant interactions and the development of defensive (emotional) responses in the offspring. Females displayed less interest in males that had experienced predator odor. Mothers that reared young in larger, seminaturalistic housing provided more licking and grooming and active arched back-nursing behavior toward their offspring compared with dams housed in standard housing, although some effects interacted with paternal experience. Paternal predation risk and maternal rearing environment revealed sex-dependent differences in offspring wean weight, juvenile social interactions, and anxiety-like behavior in adolescence. Additionally, paternal predator experience and maternal housing independently affected variations in crf gene promoter acetylation and crf gene expression in response to an acute stressor in offspring. Our results show for the first time in mammals that variation among males in their predator encounters may contribute to stable behavioral variation among females in preference for mates and maternal care, even when the females are not directly exposed to predator threat. Furthermore, when offspring were exposed to the same threat experienced by the father, hypothalamic crf gene regulation was influenced by paternal olfactory experience and early housing. These results, together with our previous findings, suggest that paternal stress exposure and maternal rearing conditions can influence maternal behavior and the development of defensive responses in offspring. PMID:27896313
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Energy conservation in stressed rats exposed to an oxytocin-injected cage mate.
Agren, Greta; Lundeberg, Thomas
2002-08-07
In previous studies we found indications of stress reduction in saline-injected rats when exposed to an oxytocin (OT)-injected cage mate. Olfactory impairment and OT antagonist treatment abolished the effects. This suggested an olfactorily mediated oxytocinergic stress-inhibitory mechanism. To test this hypothesis bodyweight, tail skin temperatures, food-intake and plasma ACTH and corticosterone concentrations were analysed. Suppressed weight loss and decreased stress-hormone release was found in saline-injected rats exposed to an OT-injected cage mate, but not in OT antagonist-injected rats, supporting the hypothesis. Our results suggest that OT in a stressed animal can inhibit the olfactory stress cues emitted, and that the olfactory cues from the stressed animal can influence an OT in pathway in the odour recipient animals to reduce stress effects.
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Mating behavior and the evolution of sperm design
Schärer, Lukas; Littlewood, D. Timothy J.; Waeschenbach, Andrea; Yoshida, Wataru; Vizoso, Dita B.
2011-01-01
Sperm are the most diverse of all animal cell types, and much of the diversity in sperm design is thought to reflect adaptations to the highly variable conditions under which sperm function and compete to achieve fertilization. Recent work has shown that these conditions often evolve rapidly as a consequence of multiple mating, suggesting a role for sexual selection and sexual conflict in the evolution of sperm design. However, very little of the striking diversity in sperm design is understood functionally, particularly in internally fertilizing organisms. We use phylogenetic comparative analyses covering 16 species of the hermaphroditic flatworm genus Macrostomum to show that a complex sperm design is associated with reciprocal mating and that this complexity is lost secondarily when hypodermic insemination—sperm injection through the epidermis—evolves. Specifically, the complex sperm design, which includes stiff lateral bristles, is likely a male persistence trait associated with sexual conflicts over the fate of received ejaculates and linked to female resistance traits, namely an intriguing postcopulatory sucking behavior and a thickened epithelium of the sperm-receiving organ. Our results suggest that the interactions between sperm donor, sperm, and sperm recipient can change drastically when hypodermic insemination evolves, involving convergent evolution of a needle-like copulatory organ, a simpler sperm design, and a simpler female genital morphology. Our study documents that a shift in the mating behavior may alter fundamentally the conditions under which sperm compete and thereby lead to a drastic change in sperm design. PMID:21220334
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Genetic benefits of a female mating preference in gray tree frogs are context-dependent.
Welch, Allison M
2003-04-01
"Good genes" models of sexual selection predict that male courtship displays can advertise genetic quality and that, by mating with males with extreme displays, females can obtain genetic benefits for their offspring. However, because the relative performance of different genotypes can vary across environments, these genetic benefits may depend on the environmental context; in which case, static mating preferences may not be adaptive. To better understand how selection acts on the preference that female gray tree frogs (Hyla versicolor) express for long advertisement calls, I tested for genetic benefits in two realistic natural environments, by comparing the performance of half-sibling offspring sired by males with long versus short calls. Tadpoles from twelve such maternal half-sibships were raised in enclosures in their natal pond at two densities. In the low-density treatment, offspring of long-call males were larger at metamorphosis than were offspring of short-call males, whereas in the high-density treatment, offspring of males with long calls tended to metamorphose later than offspring of males with short calls. Thus, although the genes indicated by long calls were advantageous under low-density conditions, they were not beneficial under all conditions, suggesting that a static preference for long calls may not be adaptive in all environments. Such a genotype-by-environment interaction in the genetic consequences of mate choice predicts that when the environment is variable, selection may favor plasticity in female preferences or female selectivity among environments to control the conditions experienced by the offspring.
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Density-dependent selection on mate search and evolution of Allee effects.
Berec, Luděk; Kramer, Andrew M; Bernhauerová, Veronika; Drake, John M
2018-01-01
Sexually reproducing organisms require males and females to find each other. Increased difficulty of females finding mates as male density declines is the most frequently reported mechanism of Allee effects in animals. Evolving more effective mate search may alleviate Allee effects, but may depend on density regimes a population experiences. In particular, high-density populations may evolve mechanisms that induce Allee effects which become detrimental when populations are reduced and maintained at a low density. We develop an individual-based, eco-genetic model to study how mating systems and fitness trade-offs interact with changes in population density to drive evolution of the rate at which males or females search for mates. Finite mate search rate triggers Allee effects in our model and we explore how these Allee effects respond to such evolution. We allow a population to adapt to several population density regimes and examine whether high-density populations are likely to reverse adaptations attained at low densities. We find density-dependent selection in most of scenarios, leading to search rates that result in lower Allee thresholds in populations kept at lower densities. This mainly occurs when fecundity costs are imposed on mate search, and provides an explanation for why Allee effects are often observed in anthropogenically rare species. Optimizing selection, where the attained trait value minimizes the Allee threshold independent of population density, depended on the trade-off between search and survival, combined with monogamy when females were searching. Other scenarios led to runaway selection on the mate search rate, including evolutionary suicide. Trade-offs involved in mate search may thus be crucial to determining how density influences the evolution of Allee effects. Previous studies did not examine evolution of a trait related to the strength of Allee effects under density variation. We emphasize the crucial role that mating systems, fitness trade-offs and the evolving sex have in determining the density threshold for population persistence, in particular since evolution need not always take the Allee threshold to its minimum value. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.
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Banks, S C; Ward, S J; Lindenmayer, D B; Finlayson, G R; Lawson, S J; Taylor, A C
2005-05-01
Habitat fragmentation is one of the major contributors to the loss of biodiversity worldwide. However, relatively little is known about its more immediate impacts on within-patch population processes such as social structure and mating systems, whose alteration may play an important role in extinction risk. We investigated the impacts of habitat fragmentation due to the establishment of an exotic softwood plantation on the social kin structure and breeding system of the Australian marsupial carnivore, Antechinus agilis. Restricted dispersal by males in fragmented habitat resulted in elevated relatedness among potential mates in populations in fragments, potentially increasing the risk of inbreeding. Antechinus agilis nests communally in tree hollows; these nests are important points for social contact between males and females in the mating season. In response to elevated relatedness among potential mates in fragmented habitat, A. agilis significantly avoided sharing nests with opposite-sex relatives in large fragment sites (but not in small ones, possibly due to limited nest locations and small population sizes). Because opposite-sex individuals shared nests randomly with respect to relatedness in unfragmented habitat, we interpreted the phenomenon in fragmented habitat as a precursor to inbreeding avoidance via mate choice. Despite evidence that female A. agilis at high inbreeding risk selected relatively unrelated mates, there was no overall increased avoidance of related mates by females in fragmented habitats compared to unfragmented habitats. Simulations indicated that only dispersal, and not nonrandom mating, contributed to inbreeding avoidance in either habitat context. However, habitat fragmentation did influence the mating system in that the degree of multiple paternity was reduced due to the reduction in population sizes and population connectivity. This, in turn, reduced the number of males available to females in the breeding season. This suggests that in addition to the obvious impacts of reduced recruitment, patch recolonization and increased genetic drift, the isolation of populations in habitat patches may cause changes in breeding behaviour that contribute to the negative impacts of habitat fragmentation.
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Environmental Factors Can Influence Mitochondrial Inheritance in the Saccharomyces Yeast Hybrids.
Hsu, Yu-Yi; Chou, Jui-Yu
2017-01-01
Mitochondria play a critical role in the generation of metabolic energy and are crucial for eukaryotic cell survival and proliferation. In most sexual eukaryotes, mitochondrial DNA (mtDNA) is inherited from only one parent in non-Mendelian inheritance in contrast to the inheritance of nuclear DNA. The model organism Saccharomyces cerevisiae is commonly used to study mitochondrial biology. It has two mating types: MATa and MATα. Previous studies have suggested that the mtDNA inheritance patterns in hybrid diploid cells depend on the genetic background of parental strains. However, the underlying mechanisms remain unclear. To elucidate the mechanisms, we examined the effects of environmental factors on the mtDNA inheritance patterns in hybrids obtained by crossing S. cerevisiae with its close relative S. paradoxus. The results demonstrated that environmental factors can influence mtDNA transmission in hybrid diploids, and that the inheritance patterns are strain dependent. The fitness competition assay results showed that the fitness differences can explain the mtDNA inheritance patterns under specific conditions. However, in this study, we found that fitness differences cannot fully be explained by mitochondrial activity in hybrids under stress conditions.
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Acoustic experience shapes female mate choice in field crickets
Bailey, Nathan W; Zuk, Marlene
2008-01-01
Female choice can drive the evolution of extravagant male traits. In invertebrates, the influence of prior social experience on female choice has only recently been considered. To better understand the evolutionary implications of experience-mediated plasticity in female choice, we investigated the effect of acoustic experience during rearing on female responsiveness to male song in the field cricket Teleogryllus oceanicus. Acoustic experience has unique biological relevance in this species: a morphological mutation has rendered over 90 per cent of males on the Hawaiian island of Kauai silent in fewer than 20 generations, impeding females' abilities to locate potential mates. Females reared in silent conditions mimicking Kauai were less discriminating of male calling song and more responsive to playbacks, compared with females that experienced song during rearing. Our results to our knowledge, are the first demonstration of long-term effects of acoustic experience in an arthropod, and suggest that female T. oceanicus may be able to compensate for the reduced availability of long-range male sexual signals by increasing their responsiveness to the few remaining signallers. Understanding the adaptive significance of experience-mediated plasticity in female choice provides insight into processes that facilitate rapid evolutionary change and shape sexual selection pressure in natural populations. PMID:18700205
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Silveira, Sarita; Graupmann, Verena; Agthe, Maria; Gutyrchik, Evgeny; Blautzik, Janusch; Demirçapa, Idil; Berndt, Andrea; Pöppel, Ernst; Frey, Dieter; Reiser, Maximilian
2014-01-01
Being reminded of the inherently finite nature of human existence has been demonstrated to elicit strivings for sexual reproduction and the formation and maintenance of intimate relationships. Recently, it has been proposed that the perception of potential mating partners is influenced by mortality salience. Using functional magnetic resonance imaging, we investigated the neurocognitive processing of attractive opposite-sex faces after priming with death-related words for heterosexual men and women. Significant modulations of behavioral and neural responses were found when participants were requested to decide whether they would like to meet the presented person. Men were more in favor of meeting attractive women after being primed with death-related words compared to a no-prime condition. Increased neural activation could be found under mortality salience in the left anterior insula and the adjacent lateral prefrontal cortex (lPFC) for both men and women. As previously suggested, we believe that the lPFC activation reflects an approach-motivated defense mechanism to overcome concerns that are induced by being reminded of death and dying. Our results provide insight on a neurocognitive level that approach motivation in general, and mating motivation in particular is modulated by mortality salience. PMID:24078106
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Social wasps are a Saccharomyces mating nest.
Stefanini, Irene; Dapporto, Leonardo; Berná, Luisa; Polsinelli, Mario; Turillazzi, Stefano; Cavalieri, Duccio
2016-02-23
The reproductive ecology of Saccharomyces cerevisiae is still largely unknown. Recent evidence of interspecific hybridization, high levels of strain heterozygosity, and prion transmission suggest that outbreeding occurs frequently in yeasts. Nevertheless, the place where yeasts mate and recombine in the wild has not been identified. We found that the intestine of social wasps hosts highly outbred S. cerevisiae strains as well as a rare S. cerevisiae×S. paradoxus hybrid. We show that the intestine of Polistes dominula social wasps favors the mating of S. cerevisiae strains among themselves and with S. paradoxus cells by providing a succession of environmental conditions prompting cell sporulation and spores germination. In addition, we prove that heterospecific mating is the only option for European S. paradoxus strains to survive in the gut. Taken together, these findings unveil the best hidden secret of yeast ecology, introducing the insect gut as an environmental alcove in which crosses occur, maintaining and generating the diversity of the ascomycetes.
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Mate desertion in the snail kite
Beissinger, S.R.; Snyder, N.F.R.
1988-01-01
Mate desertion during the breeding cycle was documented at 28 of 36 (78%) snail kite, Rostrhamus sociabilis nests in Florida between 1979 and 1983. Offspring mortality occurred at only one deserted nest, however. Parents that were deserted by their mates continued to care for their young until independence (3?5 additional weeks) and provided snails at a rate similar to that of both parents combined before desertion. Males and females deserted with nearly equal frequency, except in 1982 when more females deserted. No desertion occurred during drought years, whereas desertion occurred at nearly every nest during favourable conditions. The occurrence of mate desertion was generally related to indirect measures of snail abundance: foraging range, snail delivery rates to the young and growth rates. Small broods were deserted more frequently by females than by males and tended to be deserted earlier than large ones. After desertion, deserters had the opportunity to re-mate and nest again since breeding seasons were commonly lengthy, but whether they did so was impossible to determine conclusively in most cases. The deserted bird sometimes incurred increased energetic costs and lost breeding opportunities during periods of monoparental care.
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Lima-Camara, Tamara Nunes; Codeço, Claudia Torres; Honório, Nildimar Alves; Bruno, Rafaela Vieira; Peixoto, Alexandre Afranio; Lounibos, Leon Philip
2013-01-01
Dengue is one of the world’s most important mosquito-borne diseases and is usually transmitted by one of two vector species: Aedes aegypti or Aedes albopictus . These two diurnal mosquitoes are frequently found coexisting in similar habitats, enabling interactions between adults, such as cross-mating. The objective of this study was to assess cross-mating between Ae. aegypti females and Ae. albopictus males under artificial conditions and evaluate the locomotor activity of Ae. aegypti virgin females injected with male accessory gland (MAG) homogenates to infer the physiological and behavioural responses to interspecific mating. After seven days of exposure, 3.3-16% of Ae. aegypti females mated with Ae. albopictus males. Virgin Ae. aegypti females injected with conspecific and heterospecific MAGs showed a general decrease in locomotor activity compared to controls and were refractory to mating with conspecific males. The reduction in diurnal locomotor activity induced by injections of conspecific or heterospecific MAGs is consistent with regulation of female reproductive activities by male substances, which are capable of sterilising female Ae. aegypti through satyrisation by Ae. albopictus . PMID:24473799
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Methyl farnesoate levels in male spider crabs exhibiting active reproductive behavior.
Sagi, A; Ahl, J S; Danaee, H; Laufer, H
1994-09-01
The concentration of methyl farnesoate (MF) in the hemolymph and its synthesis by the mandibular organs (MOs) were investigated to determine whether this compound is related to the differences in the size of the reproductive system and the mating behavior among male morphotypes of the spider crab, Libinia emarginata. Large-claw abraded males displayed mating behavior under competitive conditions. They have the largest reproductive systems, their MOs synthesize large amounts of MF in vitro, and the concentration of MF in their hemolymph is high. Small-claw abraded males displayed mating behavior with receptive females only when isolated. These smaller crabs have intermediate-sized reproductive systems, their MOs synthesize the most MF, and they have the highest circulating level of MF relative to their body size. The unabraded males did not display mating behavior; their reproductive systems are smaller; their MO activity is low, as is their circulating level of MF. The strong relationship between MF levels and the intensity of reproductive behavior suggests that MF may be one of the driving forces behind mating behavior in Crustacea.
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Female sticklebacks use male coloration in mate choice and hence avoid parasitized males
NASA Astrophysics Data System (ADS)
Milinski, Manfred; Bakker, Theo C. M.
1990-03-01
AN important problem in evolutionary biology since the time of Darwin has been to understand why females preferentially mate with males handicapped by secondary sexual ornaments1-3. One hypothesis of sexual selection theory is that these ornaments reliably reveal the male's condition4-6, which can be affected for example by parasites4,7-13. Here we show that in the three-spined stickleback (Gasterosteus aculeatus) the intensity of male red breeding coloration positively correlates with physical condition. Gravid females base their active mate choice on the intensity of the male's red coloration. Choice experiments under green light prevent the use of red colour cues by females, and males that were previously preferred are now chosen no more than randomly, although the courtship behaviour of the males remains unchanged. Parasitieation causes a deterioration in the males' condition and a decrease in the intensity of their red coloration. Tests under both lighting conditions reveal that the females recognize the formerly parasitized males by the lower intensity of their breeding coloration. Female sticklebacks possibly select a male with a good capacity for paternal care14 but if there is additive genetic variation for parasite resistance, then they might also select for resistance genes, as proposed by Hamilton and Zuk4.
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The effect of mortality salience on women's judgments of male faces.
Vaughn, James E; Bradley, Kristopher I; Byrd-Craven, Jennifer; Kennison, Shelia M
2010-08-30
Previous research has shown that individuals who are reminded of their death exhibited a greater desire for offspring than those who were not reminded of their death. The present research investigated whether being reminded of mortality affects mate selection behaviors, such as facial preference judgments. Prior research has shown that women prefer more masculine faces when they are at the high versus low fertility phase of their menstrual cycles. We report an experiment in which women were tested either at their high or fertility phase. They were randomly assigned to either a mortality salience (MS) or control condition and then asked to judge faces ranging from extreme masculine to extreme feminine. The results showed that women's choice of the attractive male face was determined by an interaction between fertility phase and condition. In control conditions, high fertility phase women preferred a significantly more masculine face than women who were in a lower fertility phase of their menstrual cycles. In MS conditions, high fertility phase women preferred a significantly less masculine (i.e., more average) face than women who were in a low fertility phase. The results indicate that biological processes, such as fertility phase, involved in mate selection are sensitive to current environmental factors, such as death reminders. This sensitivity may serve as an adaptive compromise when choosing a mate in potentially adverse environmental conditions.
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2011-01-01
Background Both natural and sexual selection are thought to influence genetic diversity, but the study of the relative importance of these two factors on ecologically-relevant traits has traditionally focused on species with conventional sex-roles, with male-male competition and female-based mate choice. With its high variability and significance in both immune function and olfactory-mediated mate choice, the major histocompatibility complex (MHC/MH) is an ideal system in which to evaluate the relative contributions of these two selective forces to genetic diversity. Intrasexual competition and mate choice are both reversed in sex-role reversed species, and sex-related differences in the detection and use of MH-odor cues are expected to influence the intensity of sexual selection in such species. The seahorse, Hippocampus abdominalis, has an exceptionally highly developed form of male parental care, with female-female competition and male mate choice. Results Here, we demonstrate that the sex-role reversed seahorse has a single MH class II beta-chain gene and that the diversity of the seahorse MHIIβ locus and its pattern of variation are comparable to those detected in species with conventional sex roles. Despite the presence of only a single gene copy, intralocus MHIIβ allelic diversity in this species exceeds that observed in species with multiple copies of this locus. The MHIIβ locus of the seahorse exhibits a novel expression domain in the male brood pouch. Conclusions The high variation found at the seahorse MHIIβ gene indicates that sex-role reversed species are capable of maintaining the high MHC diversity typical in most vertebrates. Whether such species have evolved the capacity to use MH-odor cues during mate choice is presently being investigated using mate choice experiments. If this possibility can be rejected, such systems would offer an exceptional opportunity to study the effects of natural selection in isolation, providing powerful comparative models for understanding the relative importance of selective factors in shaping patterns of genetic variation. PMID:21569286
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NASA Technical Reports Server (NTRS)
Dellacorte, Christopher; Thomas, Fransua; Leak, Olivia Ann
2015-01-01
A series of pin-on-disk sliding wear tests were undertaken to identify candidate materials for a pair of lightly loaded timing gears operating under highly humid conditions. The target application involves water purification and thus precludes the use of oil, grease and potentially toxic solid lubricants. The baseline sliding pair is austenitic stainless steel operating against a carbon filled polyimide. The test load and sliding speed (4.9 N, 2.7 m/s) were chosen to represent average contact conditions of the meshing gear teeth. In addition to the baseline materials, the hard superelastic NiTiNOL 60 (60NiTi) was slid against itself, against the baseline polyimide, and against 60NiTi onto which a commercially deposited dry film lubricant (DFL) was applied. The alternate materials were evaluated as potential replacements to achieve a longer wear life and improved dimensional stability for the timing gear application. An attempt was also made to provide solid lubrication to self-mated 60NiTi by rubbing the polyimide against the disk wear track outside the primary 60NiTi-60NiTi contact, a method named stick or transfer-film lubrication. The selected test conditions gave repeatable friction and wear data and smooth sliding surfaces for the baseline materials similar to those in the target application. Friction and wear for self-mated stainless steel were high and erratic. Self-mated 60NiTi gave acceptably low friction (approx. 0.2) and modest wear but the sliding surfaces were rough and potentially unsuitable for the gear application. Tests in which 60NiTi pins were slid against DFL coated 60NiTi and DFL coated stainless steel gave low friction and long wear life. The use of stick lubrication via the secondary polyimide pin provided effective transfer film lubrication to self-mated 60NiTi tribological specimens. Using this approach, friction levels were equal or lower than the baseline polyimide-stainless combination and wear was higher but within data scatter observed in these preliminary tests. Based upon these results, self-mated 60NiTi gear teeth utilizing solid lubrication, is a reasonable approach for the target application.
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NASA Technical Reports Server (NTRS)
DellaCorte, Christopher; Thomas, Fransua; Leak, Olivia Ann
2015-01-01
A series of pin-on-disk sliding wear tests were undertaken to identify candidate materials for a pair of lightly loaded timing gears operating under highly humid conditions. The target application involves water purification and thus precludes the use of oil, grease and potentially toxic solid lubricants. The baseline sliding pair is austenitic stainless steel operating against a carbon filled polyimide. The test load and sliding speed (4.9N, 2.7ms) were chosen to represent average contact conditions of the meshing gear teeth. In addition to the baseline materials, the hard superelastic NiTiNOL 60 (60NiTi) was slid against itself, against the baseline polyimide, and against 60NiTi onto which a commercially deposited dry film lubricant (DFL) was applied. The alternate materials were evaluated as potential replacements to achieve a longer wear life and improved dimensional stability for the timing gear application. An attempt was also made to provide solid lubrication to self-mated 60NiTi by rubbing the polyimide against the disk wear track outside the primary 60NiTi-60NiTi contact, a method named stick or transfer-film lubrication. The selected test conditions gave repeatable friction and wear data and smooth sliding surfaces for the baseline materials similar to those in the target application. Friction and wear for self-mated stainless steel were high and erratic. Self-mated 60NiTi gave acceptably low friction (0.2) and modest wear but the sliding surfaces were rough and potentially unsuitable for the gear application. Tests in which 60NiTi pins were slid against DFL coated 60NiTi and DFL coated stainless steel gave low friction and long wear life. The use of stick lubrication via a secondary polyimide pin provided effective transfer film lubrication to self-mated 60NiTi tribological specimens. Using this approach, friction levels were equal or lower than the baseline polyimide-stainless combination and wear was higher but within data scatter observed in these preliminary tests. Based upon these results, self-mated 60NiTi gear teeth utilizing solid lubrication, is a reasonable approach for the target application.
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Cross-generational effects of sexual harassment on female fitness in the guppy.
Gasparini, Clelia; Devigili, Alessandro; Pilastro, Andrea
2012-02-01
Sexual harassment is a common outcome of sexual conflict over mating rate. A large number of studies have identified several direct costs to females of sexual harassment including energy expenditure and reduced foraging ability. However, the fitness consequences of sexual harassment for descendants have rarely been investigated. Here, we manipulated the level of sexual harassment and mating rate in two groups of female guppies, Poecilia reticulata, a live-bearing fish in which sexual conflict over mating rate is particularly pronounced. Each female was allowed to interact with three males for one day (low sexual harassment, LSH) or for eight days (high sexual harassment, HSH) during each breeding cycle throughout their life. Female lifetime fecundity did not differ between the groups, but we found a strong effect on offspring fitness. HSH females produced (1) daughters with smaller bodies and (2) sons with shorter gonopodia, which were less attractive to females and less successful in coercive matings than their LSH counterparts. Although these results may be influenced by the indirect effects of sex ratio differences between treatments, they suggest that sexual harassment and elevated mating rate can have negative cross-generational fitness effects and more profound evolutionary consequences than currently thought. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
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Embryonic origin of mate choice in a lizard with temperature-dependent sex determination.
Putz, Oliver; Crews, David
2006-01-01
Individual differences in the adult sexual behavior of vertebrates are rooted in the fetal environment. In the leopard gecko (Eublepharis macularius), a species with temperature-dependent sex determination (TSD), hatchling sex ratios differ between incubation temperatures, as does sexuality in same-sex animals. This variation can primarily be ascribed to the temperature having direct organizing actions on the brain. Here we demonstrate that embryonic temperature can affect adult mate choice in the leopard gecko. Given the simultaneous choice between two females from different incubation temperatures (30.0 and 34.0 degrees C), males from one incubation temperature (30.0 degrees C) preferred the female from 34.0 degrees C, while males from another incubation temperature (32.5 degrees C) preferred the female from 30.0 degrees C. We suggest that this difference in mate choice is due to an environmental influence on brain development leading to differential perception of opposite-sex individuals. This previously unrecognized modulator of adult mate choice lends further support to the view that mate choice is best understood in the context of an individual's entire life-history. Thus, sexual selection results from a combination of the female's as well as the male's life history. Female attractiveness and male choice therefore are complementary. Copyright 2005 Wiley Periodicals, Inc.
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MHC, mate choice and heterozygote advantage in a wild social primate.
Huchard, Elise; Knapp, Leslie A; Wang, Jinliang; Raymond, Michel; Cowlishaw, Guy
2010-06-01
Preferences for mates carrying dissimilar genes at the major histocompatibility complex (MHC) may help animals increase offspring pathogen resistance or avoid inbreeding. Such preferences have been reported across a range of vertebrates, but have rarely been investigated in social species other than humans. We investigated mate choice and MHC dynamics in wild baboons (Papio ursinus). MHC Class II DRB genes and 16 microsatellite loci were genotyped across six groups (199 individuals). Based on the survey of a key segment of the gene-rich MHC, we found no evidence of mate choice for MHC dissimilarity, diversity or rare MHC genotypes. First, MHC dissimilarity did not differ from random expectation either between parents of the same offspring or between immigrant males and females from the same troop. Second, female reproductive success was not influenced by MHC diversity or genotype frequency. Third, population genetic structure analysis revealed equally high genotypic differentiation among troops, and comparable excess heterozygosity within troops for juveniles, at both Mhc-DRB and neutral loci. Nevertheless, the age structure of Mhc-DRB heterozygosity suggested higher longevity for heterozygotes, which should favour preferences for MHC dissimilarity. We propose that high levels of within-group outbreeding, resulting from group-living and sex-biased dispersal, might weaken selection for MHC-disassortative mate choice.
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Goodisman, MAD.; Asmussen, M. A.
1997-01-01
We develop models that describe the cytonuclear structure for either a cytoplasmic and nuclear marker in a haplodiploid species or a cytoplasmic and X-linked marker in a diploid species. Sex-specific disequilibrium statistics that summarize nonrandom cytonuclear associations in such systems are defined, and their basic Hardy-Weinberg dynamics and admixture formulae are delimited. We focus on the context of hybrid zones and develop continent-island models whereby individuals from two genetically differentiated source populations migrate into and mate within a single zone of admixture. We examine the effects of differential migration of the sexes, assortative mating by pure type females, and census time (relative to mating and migration), as well as special cases of random mating and migration subsumed under the general models. We show that pure type individuals and nonzero cytonuclear disequilibria can be maintained within a hybrid zone if there is continued migration from both source populations, and that females generally have a greater influence over these cytonuclear variables than males. The resulting theoretical framework can be used to estimate the rates of assortative mating and sex-specific gene flow in hybrid zones and other zones of admixture involving haplodiploid or sex-linked cytonuclear data. PMID:9286692
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Olson, V A; Liker, A; Freckleton, R P; Székely, T
2008-02-07
Parents often conflict over how much care to provide to their offspring. This conflict is expected to produce a negative relationship between male and female parental care, the strength of which may be mediated by both ecological and life-history variables. Previous studies have observed such trade-offs, but it is not known how generally they occur. Traditional views of sexual conflict place great importance on ecological factors in determining levels of parental care, whereas alternative views propose that the key determinant is mating opportunity. We carried out a broad-scale comparative study of parental conflict using 193 species from 41 families of birds. Using phylogenetic comparative analysis, we establish the generality of intersexual parental care conflict. We also show that parental conflict, as indicated by the disparity in care between the male and the female, depends on offspring development and mating opportunities, since in precocial species both males and females responded to increased mating opportunities. Altricial birds, however, failed to show these relationships. We also found little influence of breeding climate on parental conflict. Taken together, our results suggest that sexual conflict is a key element in the evolution of parental care systems. They also support the view that the major correlates of the intersexual conflict are mating opportunities for both sexes, rather than the breeding environment.
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Centrifugation effects on estrous cycle, mating success and pregnancy outcome in rats
NASA Astrophysics Data System (ADS)
Ronca, April E.; Rushing, Linda; Tou, Janet; Wade, Charles E.; Baer, Lisa A.
2005-08-01
We analyzed the effects of 2-g centrifugation on estrous cycling, mating success and pregnancy outcome in rats. Sexually mature female and male rats were assigned to either 2-g centrifuge or non-centrifuge conditions, and to non-breeding or breeding conditions. In non-breeding females, estrous cycles were analyzed by examining vaginal cytology before and for 35 days during centrifugation. Breeding females were time-mated following 7 days of adaptation to centrifugation. Following adaptation to centrifugation, estrous cycle duration over a five-cycle period was similar in centrifuged and non-centrifuged females. Identical numbers of centrifuged and non-centrifuged females conceived, however centrifuged females took four-times longer than controls to achieve conception. Births occurred at the normal gestational length. Pup birth weight and postnatal survival were p<0.05 reduced in centrifuged as compared to non-centrifuged groups. In conclusion, 2-g centrifugation had no effect on estrus cycle length or the probably of becoming pregnant but delayed conception and diminished pregnancy outcome.
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Centrifugation Effects on Estrous Cycling, Mating Success and Pregnancy Outcome in Rats
NASA Technical Reports Server (NTRS)
Ronca, April E.; Rushing, Linda S.; Tou, Janet; Wade, Charles E.; Baer, Lisa A.
2005-01-01
We analyzed the effects of 2-g centrifugation on estrous cycling, mating success and pregnancy outcome in rats. Sexually mature female and male rats were assigned to either 2-g centrifuge or non-centrifuge conditions, and to non-breeding or breeding conditions. In non-breeding females, estrous cycles were analyzed by examining vaginal cytology before and for 35 days during centrifugation. Breeding females were time-mated following 7 days of adaptation to centrifugation. Following adaptation to centrifugation, estrous cycle duration over a five-cycle period was similar in centrifuged and non-centrifuged females. Identical numbers of centrifuged and non-centrifuged females conceived, however centrifuged females took four-times longer than controls to achieve conception. Births occurred at the normal gestational length. Pup birth weight and postnatal survival were p<0.05 reduced in centrifuged as compared to non-centrifuged groups. In conclusion, 2-g centrifugation had no effect on estrous cycle length or the probably of becoming pregnant but delayed conception and diminished pregnancy outcome.
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Presenting Your Best Self(ie): The Influence of Gender on Vertical Orientation of Selfies on Tinder.
Sedgewick, Jennifer R; Flath, Meghan E; Elias, Lorin J
2017-01-01
When taking a self-portrait or "selfie" to display in an online dating profile, individuals may intuitively manipulate the vertical camera angle to embody how they want to be perceived by the opposite sex. Concepts from evolutionary psychology and grounded cognition suggest that this manipulation can provide cues of physical height and impressions of power to the viewer which are qualities found to influence mate-selection. We predicted that men would orient selfies more often from below to appear taller (i.e., more powerful) than the viewer, and women, from an above perspective to appear shorter (i.e., less powerful). A content analysis was conducted which coded the vertical orientation of 557 selfies from profile pictures on the popular mobile dating application, Tinder. In general, selfies were commonly used by both men (54%) and women (90%). Consistent with our predictions, a gender difference emerged; men's selfies were angled significantly more often from below, whereas women's were angled more often from above. Our findings suggest that selfies presented in a mate-attraction context are intuitively or perhaps consciously selected to adhere to ideal mate qualities. Further discussion proposes that biological or individual differences may also facilitate vertical compositions of selfies.
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The persistence of facultative parthenogenesis in Drosophila albomicans.
Chang, Chia-chen; Ting, Chau-Ti; Chang, Ching-Ho; Fang, Shu; Chang, Hwei-yu
2014-01-01
Parthenogenesis has evolved independently in more than 10 Drosophila species. Most cases are tychoparthenogenesis, which is occasional or accidental parthenogenesis in normally bisexual species with a low hatching rate of eggs produced by virgin females; this form is presumed to be an early stage of parthenogenesis. To address how parthenogenesis and sexual reproduction coexist in Drosophila populations, we investigated several reproductive traits, including the fertility, parthenogenetic capability, diploidization mechanisms, and mating propensity of parthenogenetic D. albomicans. The fertility of mated parthenogenetic females was significantly higher than that of virgin females. The mated females could still produce parthenogenetic offspring but predominantly produced offspring by sexual reproduction. Both mated parthenogenetic females and their parthenogenetic-sexual descendants were capable of parthenogenesis. The alleles responsible for parthenogenesis can be propagated through both parthenogenesis and sexual reproduction. As diploidy is restored predominantly by gamete duplication, heterozygosity would be very low in parthenogenetic individuals. Hence, genetic variation in parthenogenetic genomes would result from sexual reproduction. The mating propensity of females after more than 20 years of isolation from males was decreased. If mutations reducing mating propensities could occur under male-limited conditions in natural populations, decreased mating propensity might accelerate tychoparthenogenesis through a positive feedback mechanism. This process provides an opportunity for the evolution of obligate parthenogenesis. Therefore, the persistence of facultative parthenogenesis may be an adaptive reproductive strategy in Drosophila when a few founders colonize a new niche or when small populations are distributed at the edge of a species' range, consistent with models of geographical parthenogenesis.
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The Persistence of Facultative Parthenogenesis in Drosophila albomicans
Chang, Ching-Ho; Fang, Shu; Chang, Hwei-yu
2014-01-01
Parthenogenesis has evolved independently in more than 10 Drosophila species. Most cases are tychoparthenogenesis, which is occasional or accidental parthenogenesis in normally bisexual species with a low hatching rate of eggs produced by virgin females; this form is presumed to be an early stage of parthenogenesis. To address how parthenogenesis and sexual reproduction coexist in Drosophila populations, we investigated several reproductive traits, including the fertility, parthenogenetic capability, diploidization mechanisms, and mating propensity of parthenogenetic D. albomicans. The fertility of mated parthenogenetic females was significantly higher than that of virgin females. The mated females could still produce parthenogenetic offspring but predominantly produced offspring by sexual reproduction. Both mated parthenogenetic females and their parthenogenetic-sexual descendants were capable of parthenogenesis. The alleles responsible for parthenogenesis can be propagated through both parthenogenesis and sexual reproduction. As diploidy is restored predominantly by gamete duplication, heterozygosity would be very low in parthenogenetic individuals. Hence, genetic variation in parthenogenetic genomes would result from sexual reproduction. The mating propensity of females after more than 20 years of isolation from males was decreased. If mutations reducing mating propensities could occur under male-limited conditions in natural populations, decreased mating propensity might accelerate tychoparthenogenesis through a positive feedback mechanism. This process provides an opportunity for the evolution of obligate parthenogenesis. Therefore, the persistence of facultative parthenogenesis may be an adaptive reproductive strategy in Drosophila when a few founders colonize a new niche or when small populations are distributed at the edge of a species' range, consistent with models of geographical parthenogenesis. PMID:25415200
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Nandi, Diptarup; Balakrishnan, Rohini
2016-01-01
Amount of calling activity (calling effort) is a strong determinant of male mating success in species such as orthopterans and anurans that use acoustic communication in the context of mating behaviour. While many studies in crickets have investigated the determinants of calling effort, patterns of variability in male calling effort in natural choruses remain largely unexplored. Within-individual variability in calling activity across multiple nights of calling can influence female mate search and mate choice strategies. Moreover, calling site fidelity across multiple nights of calling can also affect the female mate sampling strategy. We therefore investigated the spatio-temporal dynamics of acoustic signaling behaviour in a wild population of the field cricket species Plebeiogryllus guttiventris. We first studied the consistency of calling activity by quantifying variation in male calling effort across multiple nights of calling using repeatability analysis. Callers were inconsistent in their calling effort across nights and did not optimize nightly calling effort to increase their total number of nights spent calling. We also estimated calling site fidelity of males across multiple nights by quantifying movement of callers. Callers frequently changed their calling sites across calling nights with substantial displacement but without any significant directionality. Finally, we investigated trade-offs between within-night calling effort and energetically expensive calling song features such as call intensity and chirp rate. Calling effort was not correlated with any of the calling song features, suggesting that energetically expensive song features do not constrain male calling effort. The two key features of signaling behaviour, calling effort and call intensity, which determine the duration and spatial coverage of the sexual signal, are therefore uncorrelated and function independently.
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The role of ecology in speciation by sexual selection: a systematic empirical review.
Scordato, Elizabeth S C; Symes, Laurel B; Mendelson, Tamra C; Safran, Rebecca J
2014-01-01
Theoretical and empirical research indicates that sexual selection interacts with the ecological context in which mate choice occurs, suggesting that sexual and natural selection act together during the evolution of premating reproductive isolation. However, the relative importance of natural and sexual selection to speciation remains poorly understood. Here, we applied a recent conceptual framework for examining interactions between mate choice divergence and ecological context to a review of the empirical literature on speciation by sexual selection. This framework defines two types of interactions between mate choice and ecology: internal interactions, wherein natural and sexual selection jointly influence divergence in sexual signal traits and preferences, and external interactions, wherein sexual selection alone acts on traits and preferences but ecological context shapes the transmission efficacy of sexual signals. The objectives of this synthesis were 3-fold: to summarize the traits, ecological factors, taxa, and geographic contexts involved in studies of mate choice divergence; to analyze patterns of association between these variables; and to identify the most common types of interactions between mate choice and ecological factors. Our analysis revealed that certain traits are consistently associated with certain ecological factors. Moreover, among studies that examined a divergent sexually selected trait and an ecological factor, internal interactions were more common than external interactions. Trait-preference associations may thus frequently be subject to both sexual and natural selection in cases of divergent mate choice. Our results highlight the importance of interactions between sexual selection and ecology in mate choice divergence and suggest areas for future research. © The American Genetic Association. 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Schramm, B G; Casares, M; Lance, V A
1999-04-01
The Galápagos Islands are home to 11 subspecies of large terrestrial tortoises (Geochelone nigra). All Galápagos tortoises are considered endangered and approximately 12,000 animals still exist. Until now, the reproductive cycle of the Galápagos tortoise has been studied only in captive animals, and no data from free-ranging tortoises have been available. During a one-year period, blood samples were collected from male and female G. nigra living under seminatural conditions on Santa Cruz Island, Galápagos. Plasma steroid hormones were measured by radioimmunoassays (RIAs). In males, plasma testosterone and corticosterone increased a few months before the onset of the mating season. Peak levels were observed while most copulations occurred and environmental temperatures were highest. Both testosterone and corticosterone showed low levels during the cold and dry nesting season and high levels during the hot and rainy mating season. In females, testosterone and corticosterone also rose during the hot and rainy mating season. Both hormones peaked during the second half of the mating season and decreased during the cooler dry season. Female estradiol levels increased at the onset of the mating season, reaching the highest level at the peak of the mating season, which coincided with the highest annual temperatures measured. Estradiol slowly decreased within the next months and rapidly dropped at the onset of the nesting season when temperatures decreased. Progesterone levels were high close to the time of ovulation and showed clearly elevated levels at the beginning of the nesting season after some females had laid their first clutch. Progesterone decreased during the nesting season, when ambient temperatures began to decrease, and reached minimal levels in the postbreeding period shortly before the onset of the next mating season. There were significant annual variations in plasma testosterone in both males and females. Plasma corticosterone was generally higher in males than in females and varied throughout the year in both sexes. Copyright 1999 Academic Press.
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Mate value and self-esteem: evidence from eight cultural groups.
Goodwin, Robin; Marshall, Tara; Fülöp, Marta; Adonu, Joseph; Spiewak, Slawomir; Neto, Felix; Hernandez Plaza, Sonia
2012-01-01
This paper explores self-perceived mate value (SPMV), and its association with self-esteem, in eight cultures. 1066 participants, from 8 cultural groups in 7 countries, rated themselves on 24 SPMVs and completed a measure of self-esteem. Consistent with evolutionary theory, women were more likely to emphasise their caring and passionate romantic nature. In line with previous cross-cultural research, characteristics indicating passion and romance and social attractiveness were stressed more by respondents from individualistic cultures, and those higher on self-expression (rather than survival) values; characteristics indicative of maturity and confidence were more likely to be mentioned by those from Traditional, rather than Secular, cultures. Contrary to gender role theory, societal equality had only limited interactions with sex and SPMV, with honesty of greater significance for male self-esteem in societies with unequal gender roles. These results point to the importance of cultural and environmental factors in influencing self-perceived mate qualities, and are discussed in relation to broader debates about the impact of gender role equality on sex differences in personality and mating strategies.
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Ramos, Flavio Nunes; Zucchi, Maria Imaculada; Solferini, Vera Nisaka; Santos, Flavio A M
2008-02-01
The aim of this study was to determine and compare the mating systems among Psychotria tenuinervis populations at anthropogenic edges, natural edges, and the forest interior using allozyme electrophoresis of naturally pollinated progeny arrays. P. tenuinervis showed low outcrossing rates, varying from 37% to 50% of the mating attributable to outcrossing and 50% to 63% attributable to self-fertilization, in the three habitats. The forest interior had the highest outcrossing rate (t(m) = 0.50 and t(s) = 0.43) among the three habitats. However, there were no differences in either multilocus or single-locus rates among the three habitats, indicating that the contribution of biparental inbreeding to the apparent selfing rate in these populations was very low. The multilocus (t(m)) and single-locus (t(s)) outcrossing rates for the P. tenuinervis in the sample plots within each habitat showed great heterogeneity. In conclusion, edge creation seems not to influence its mating systems. Additionally, although P. tenuinervis is a distylous species, the population's inbreeding can be attributed almost entirely to self-fertilization.
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Male-induced costs of mating for females compensated by offspring viability benefits in an insect.
Garcia-Gonzalez, F; Simmons, L W
2010-10-01
Sexual conflict facilitates the evolution of traits that increase the reproductive success of males at the expense of components of female fitness. Theory suggests that indirect benefits are unlikely to offset the direct costs to females from antagonistic male adaptations, but empirical studies examining the net fitness pay-offs of the interaction between the sexes are scarce. Here, we investigate whether matings with males that invest intrinsically more into accessory gland tissue undermine female lifetime reproductive success (LRS) in the cricket Teleogryllus oceanicus. We found that females incur a longevity cost of mating that is proportional to the partner's absolute investment into the production of accessory gland products. However, male accessory gland weight positively influences embryo survival, and harmful ejaculate-induced effects are cancelled out when these are put in the context of female LRS. The direct costs of mating with males that sire offspring with higher viability are thus compensated by direct and possibly indirect genetic benefits in this species. © 2010 The Authors. Journal Compilation © 2010 European Society For Evolutionary Biology.
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Mate Value and Self-Esteem: Evidence from Eight Cultural Groups
Goodwin, Robin; Marshall, Tara; Fülöp, Marta; Adonu, Joseph; Spiewak, Slawomir; Neto, Felix; Hernandez Plaza, Sonia
2012-01-01
This paper explores self-perceived mate value (SPMV), and its association with self-esteem, in eight cultures. 1066 participants, from 8 cultural groups in 7 countries, rated themselves on 24 SPMVs and completed a measure of self-esteem. Consistent with evolutionary theory, women were more likely to emphasise their caring and passionate romantic nature. In line with previous cross-cultural research, characteristics indicating passion and romance and social attractiveness were stressed more by respondents from individualistic cultures, and those higher on self-expression (rather than survival) values; characteristics indicative of maturity and confidence were more likely to be mentioned by those from Traditional, rather than Secular, cultures. Contrary to gender role theory, societal equality had only limited interactions with sex and SPMV, with honesty of greater significance for male self-esteem in societies with unequal gender roles. These results point to the importance of cultural and environmental factors in influencing self-perceived mate qualities, and are discussed in relation to broader debates about the impact of gender role equality on sex differences in personality and mating strategies. PMID:22558347
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Montiglio, Pierre-Olivier; Wey, Tina W; Chang, Ann T; Fogarty, Sean; Sih, Andrew
2017-03-01
Despite a central line of research aimed at quantifying relationships between mating success and sexually dimorphic traits (e.g., ornaments), individual variation in sexually selected traits often explains only a modest portion of the variation in mating success. Another line of research suggests that a significant portion of the variation in mating success observed in animal populations could be explained by correlational selection, where the fitness advantage of a given trait depends on other components of an individual's phenotype and/or its environment. We tested the hypothesis that interactions between multiple traits within an individual (phenotype dependence) or between an individual's phenotype and its social environment (context dependence) can select for individual differences in behaviour (i.e., personality) and social plasticity. To quantify the importance of phenotype- and context-dependent selection on mating success, we repeatedly measured the behaviour, social environment and mating success of about 300 male stream water striders, Aquarius remigis. Rather than explaining individual differences in long-term mating success, we instead quantified how the combination of a male's phenotype interacted with the immediate social context to explain variation in hour-by-hour mating decisions. We suggest that this analysis captures more of the mechanisms leading to differences in mating success. Males differed consistently in activity, aggressiveness and social plasticity. The mating advantage of these behavioural traits depended on male morphology and varied with the number of rival males in the pool, suggesting mechanisms selecting for consistent differences in behaviour and social plasticity. Accounting for phenotype and context dependence improved the amount of variation in male mating success we explained statistically by 30-274%. Our analysis of the determinants of male mating success provides important insights into the evolutionary forces that shape phenotypic variation. In particular, our results suggest that sexual selection is likely to favour individual differences in behaviour, social plasticity (i.e., individuals adjusting their behaviour), niche preference (i.e., individuals dispersing to particular social conditions) or social niche construction (i.e., individuals modifying the social environment). The true effect of sexual traits can only be understood in interaction with the individual's phenotype and environment. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.
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Hurtado-Gonzales, Jorge L; Uy, J Albert C
2010-12-23
Intense competition for access to females can lead to males exploiting different components of sexual selection, and result in the evolution of alternative mating strategies (AMSs). Males of Poecilia parae, a colour polymorphic fish, exhibit five distinct phenotypes: drab-coloured (immaculata), striped (parae), structural-coloured (blue) and carotenoid-based red and yellow morphs. Previous work indicates that immaculata males employ a sneaker strategy, whereas the red and yellow morphs exploit female preferences for carotenoid-based colours. Mating strategies favouring the maintenance of the other morphs remain to be determined. Here, we report the role of agonistic male-male interactions in influencing female mating preferences and male mating success, and in facilitating the evolution of AMSs. Our study reveals variation in aggressiveness among P. parae morphs during indirect and direct interactions with sexually receptive females. Two morphs, parae and yellow, use aggression to enhance their mating success (i.e., number of copulations) by 1) directly monopolizing access to females, and 2) modifying female preferences after winning agonistic encounters. Conversely, we found that the success of the drab-coloured immaculata morph, which specializes in a sneak copulation strategy, relies in its ability to circumvent both male aggression and female choice when facing all but yellow males. Strong directional selection is expected to deplete genetic variation, yet many species show striking genetically-based polymorphisms. Most studies evoke frequency dependent selection to explain the persistence of such variation. Consistent with a growing body of evidence, our findings suggest that a complex form of balancing selection may alternatively explain the evolution and maintenance of AMSs in a colour polymorphic fish. In particular, this study demonstrates that intrasexual competition results in phenotypically distinct males exhibiting clear differences in their levels of aggression to exclude potential sexual rivals. By being dominant, the more aggressive males are able to circumvent female mating preferences for attractive males, whereas another male type incorporates subordinate behaviours that allow them to circumvent male aggression and female mating preferences. Together, these and previous results indicate that exploiting different aspects of social interactions may allow males to evolve distinct mating strategies and thus the long term maintenance of polymorphisms within populations.
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Miller, Lisa K; Brooks, Robert
2005-11-01
The traits thought to advertise genetic quality are often highly susceptible to environmental variation and prone to change with age. These factors may either undermine or reinforce the potential for advertisement traits to signal quality depending on the magnitude of age-dependent expression, environmental variation, and genotype-age and genotype-environment interaction. Measurements of the magnitude of these effects are thus a necessary step toward assessing the implications of age dependence and environmental variability for the evolution of signals of quality. We conducted a longitudinal study of male guppies (Poecilia reticulata) from 22 full-sibling families. Each fish was assigned at maturity to one of three treatments in order to manipulate his allocation of resources to reproduction: a control in which the male was kept alone, a courtship-only treatment in which he could see and court a female across a clear partition, and a mating treatment in which he interacted freely with a female. We measured each male's size, ornamental color patterns, courtship, attractiveness to females, and mating success at three ages. Size was influenced by treatment and age-treatment interactions, indicating that courtship and mating may impose costs on growth. Tail size and color patterns were influenced by age but not by treatment, suggesting fixed age-dependent trajectories in these advertisement traits. By contrast, display rate and attempted sneak copulation rate differed among treatments but not among ages, suggesting greater plasticity of these behavioral traits. As a result of the different patterns of variation in ornamentation and behavior, male attractiveness and mating success responded to male age, treatment, and the interaction between age and treatment. Neither age nor treatment obscured the presence of genetic variation, and the genetic relationship between male ornamentation and attractiveness remained the same among treatments. Our findings suggest that neither age-dependent variation nor environmentally induced variation in reproductive effort is likely to undermine the reliability of male signaling.
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Social factors modulate restraint stress induced hyperthermia in mice.
Watanabe, Shigeru
2015-10-22
Stress-induced hyperthermia (SIH) was examined in three different social conditions in mice by thermographic measurement of the body surface temperature. Placing animals in cylindrical holders induced restraint stress. I examined the effect of the social factors in SIH using the thermograph (body surface temperature). Mice restrained in the holders alone showed SIH. Mice restrained in the holders at the same time as other similarly restrained cage mates (social equality condition) showed less hyperthermia. Interestingly, restrained mice with free moving cage mates (social inequality condition) showed the highest hyperthermia. These results are consistent with a previous experiment measuring the memory-enhancing effects of stress and the stress-induced elevation of corticosterone, and suggest that social inequality enhances stress. Copyright © 2015 Elsevier B.V. All rights reserved.
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Zimmerman, John E.; Chan, May T.; Jackson, Nicholas; Maislin, Greg; Pack, Allan I.
2012-01-01
Study Objectives: To determine the effect of different genetic backgrounds on demographic and environmental interventions that affect sleep and evaluate variance of these measures; and to evaluate sleep and variance of sleep behaviors in 6 divergent laboratory strains of common origin. Design: Assessment of the effects of age, sex, mating status, food sources, and social experience using video analysis of sleep behavior in 2 different strains of Drosophila, white1118ex (w1118ex) and white Canton-S (wCS10). Sleep was also determined for 6 laboratory strains of Canton-S and 3 inbred lines. The variance of total sleep was determined for all groups and conditions. Measurements and Results: The circadian periods and the effects of age upon sleep were the same between w1118ex and wCS10 strains. However, the w1118ex and wCS10 strains demonstrated genotype-dependent differences in the effects upon sleep of sex, mating status, social experience, and being on different foods. Variance of total sleep was found to differ in a genotype dependent manner for interventions between the w1118ex and wCS10 strains. Six different laboratory Canton-S strains were found to have significantly different circadian periods (P < 0.001) and sleep phenotypes (P < 0.001). Three inbred lines showed reduced variance for sleep measurements. Conclusions: One must control environmental conditions in a rigorously consistent manner to ensure that sleep data may be compared between experiments. Genetic background has a significant impact upon changes in sleep behavior and variance of behavior due to demographic factors and environmental interventions. This represents an opportunity to discover new genes that modify sleep/wake behavior. Citation: Zimmerman JE; Chan MT; Jackson N; Maislin G; Pack AI. Genetic background has a major impact on differences in sleep resulting from environmental influences in Drosophila. SLEEP 2012;35(4):545-557. PMID:22467993
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An experimental test for indirect benefits in Drosophila melanogaster
Rundle, Howard D; Ödeen, Anders; Mooers, Arne Ø
2007-01-01
Background Despite much empirical attention, tests for indirect benefits of mate choice have rarely considered the major components of sexual and nonsexual offspring fitness relevant to a population. Here we use a novel experimental design to test for the existence of any indirect benefits in a laboratory adapted population of D. melanogaster. Our experiment compared the fitness (mating success, longevity, and productivity) of individuals possessing genomes that derived two generations previously from males that were either entirely successful (studs) or wholly unsuccessful (duds) at achieving mates in three subsequent rounds of mating trials. Results Males from the stud treatment were 30% more successful on average at securing mates than males from the dud treatment. In contrast, we found no difference between treatments in measures of productivity or of longevity when measured in a mixed-sex environment. In the absence of females, however, males in the stud treatment outlived males in the dud treatment. Conclusion Our results suggest that mating with successful males in this population provides an indirect benefit to females and that, at least in this environment, the benefit arises primarily through the production of more attractive male offspring. However, it is unclear whether this represents solely a traditional sexy sons benefit or whether there is an additional good genes component (with male offspring simply allocating their surplus condition to traits that enhance their mating success). The lack of any detectable differences in female fitness between the two treatments suggests the former, although the longevity advantage of males in the stud treatment when females were absent is consistent with the latter. Determining the effect of this indirect benefit on the evolution of female mate preferences (or resistance) will require comparable data on the direct costs of mating with various males, and an understanding of how these costs and benefits integrate across generations and vary among environments. PMID:17349042
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Viral Richness is Positively Related to Group Size, but Not Mating System, in Bats.
Webber, Quinn M R; Fletcher, Quinn E; Willis, Craig K R
2017-12-01
Characterizing host traits that influence viral richness and diversification is important for understanding wildlife pathogens affecting conservation and/or human health. Behaviors that affect contact rates among hosts could be important for viral diversification because more frequent intra- and inter-specific contacts among hosts should increase the potential for viral diversification within host populations. We used published data on bats to test the contact-rate hypothesis. We predicted that species forming large conspecific groups, that share their range with more heterospecifics (i.e., sympatry), and with mating systems characterized by high contact rates (polygynandry: multi-male/multi-female), would host higher viral richness than species with small group sizes, lower sympatry, or low contact-rate mating systems (polygyny: single male/multi-female). Consistent with our hypothesis and previous research, viral richness was positively correlated with conspecific group size although the relationship plateaued at group sizes of approximately several hundred thousand bats. This pattern supports epidemiological theory that, up to a point, larger groups have higher contact rates, greater likelihood of acquiring and transmitting viruses, and ultimately greater potential for viral diversification. However, contrary to our hypothesis, there was no effect of sympatry on viral richness and no difference in viral richness between mating systems. We also found no residual effect of host phylogeny on viral richness, suggesting that closely related species do not necessarily host similar numbers of viruses. Our results support the contact-rate hypothesis that intra-specific viral transmission can enhance viral diversification within species and highlight the influence of host group size on the potential of viruses to propagate within host populations.
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Exploitation of insect vibrational signals reveals a new method of pest management.
Eriksson, Anna; Anfora, Gianfranco; Lucchi, Andrea; Lanzo, Francesco; Virant-Doberlet, Meta; Mazzoni, Valerio
2012-01-01
Food production is considered to be the main source of human impact on the environment and the concerns about detrimental effects of pesticides on biodiversity and human health are likely to lead to an increasingly restricted use of chemicals in agriculture. Since the first successful field trial, pheromone based mating disruption enabled sustainable insect control, which resulted in reduced levels of pesticide use. Organic farming is one of the fastest growing segments of agriculture and with the continuously growing public concern about use of pesticides, the main remaining challenge in increasing the safety of the global food production is to identify appropriate alternative mating disruption approaches for the numerous insect pests that do not rely on chemical communication. In the present study, we show for the first time that effective mating disruption based on substrate-borne vibrational signals can be achieved in the field. When disruptive vibrational signals were applied to grapevine plants through a supporting wire, mating frequency of the leafhopper pest Scaphoideus titanus dropped to 9 % in semi-field conditions and to 4 % in a mature vineyard. The underlying mechanism of this environmentally friendly pest-control tactic is a masking of the vibrational signals used in mate recognition and location. Because vibrational communication is widespread in insects, mating disruption using substrate vibrations can transform many open field and greenhouse based farming systems.
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Co-Evolution of the Mating Position and Male Genitalia in Insects: A Case Study of a Hangingfly
Gao, Qionghua; Hua, Baozhen
2013-01-01
Hangingflies are unique for the male providing a nuptial gift to the female during mating and taking a face-to-face hanging copulation with the female. Their male genitalia are peculiar for an extremely elongated penisfilum, a pair of well-developed epandrial lobes (9th tergum), and a pair of degenerated gonostyli. However, the co-evolution of their face-to-face copulation behavior and the male genitalia has rarely been studied hitherto. In this paper the mating behavior of the hangingfly Bittacus planus Cheng, 1949 was observed under laboratory conditions, and the morphology of the male and female external genitalia was investigated using light and scanning electron microscopy. The male provides an insect prey as a nuptial gift to the female in courtship and mating process, and commits a face-to-face copulation. During copulation, the male abdomen twists temporarily about 180° to accommodate their face-to-face mating position. The aedeagal complex has an extremely elongated penisfilum, corresponding to the elongated spermathecal duct of the female. The well-developed epandrial lobes serve as claspers to grasp the female subgenital plate during copulation, replacing the function of gonostyli, which are greatly reduced in Bittacidae. The modified proctiger assists the penisfilum to stretch and to enter into the female spermathecal duct. The possible reasons why this species might mate face-to-face are briefly discussed. PMID:24312490
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Co-evolution of the mating position and male genitalia in insects: a case study of a hangingfly.
Gao, Qionghua; Hua, Baozhen
2013-01-01
Hangingflies are unique for the male providing a nuptial gift to the female during mating and taking a face-to-face hanging copulation with the female. Their male genitalia are peculiar for an extremely elongated penisfilum, a pair of well-developed epandrial lobes (9th tergum), and a pair of degenerated gonostyli. However, the co-evolution of their face-to-face copulation behavior and the male genitalia has rarely been studied hitherto. In this paper the mating behavior of the hangingfly Bittacus planus Cheng, 1949 was observed under laboratory conditions, and the morphology of the male and female external genitalia was investigated using light and scanning electron microscopy. The male provides an insect prey as a nuptial gift to the female in courtship and mating process, and commits a face-to-face copulation. During copulation, the male abdomen twists temporarily about 180° to accommodate their face-to-face mating position. The aedeagal complex has an extremely elongated penisfilum, corresponding to the elongated spermathecal duct of the female. The well-developed epandrial lobes serve as claspers to grasp the female subgenital plate during copulation, replacing the function of gonostyli, which are greatly reduced in Bittacidae. The modified proctiger assists the penisfilum to stretch and to enter into the female spermathecal duct. The possible reasons why this species might mate face-to-face are briefly discussed.
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Facial attractiveness judgements reflect learning of parental age characteristics.
Perrett, David I; Penton-Voak, Ian S; Little, Anthony C; Tiddeman, Bernard P; Burt, D Michael; Schmidt, Natalie; Oxley, Roz; Kinloch, Nicholas; Barrett, Louise
2002-05-07
Mate preferences are shaped by infant experience of parental characteristics in a wide variety of species. Similar processes in humans may lead to physical similarity between parents and mates, yet this possibility has received little attention. The age of parents is one salient physical characteristic that offspring may attend to. The current study used computer-graphic faces to examine how preferences for age in faces were influenced by parental age. We found that women born to 'old' parents (over 30) were less impressed by youth, and more attracted to age cues in male faces than women with 'young' parents (under 30). For men, preferences for female faces were influenced by their mother's age and not their father's age, but only for long-term relationships. These data indicate that judgements of facial attractiveness in humans reflect the learning of parental characteristics.
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A neuronal pathway that controls sperm ejection and storage in female Drosophila.
Lee, Kang-Min; Daubnerová, Ivana; Isaac, R Elwyn; Zhang, Chen; Choi, Sekyu; Chung, Jongkyeong; Kim, Young-Joon
2015-03-16
In polyandrous females, sperm storage permits competition between sperm of different mates, and in some species females influence the relative fertilization success of competing sperm in favor of a preferred mate [1, 2]. In female Drosophila melanogaster, sperm competition is strongly influenced by the timing of sperm ejection from the uterus [3, 4]. Understanding how female behavior influences sperm competition requires knowledge of the neuronal mechanisms controlling sperm retention and storage, which is currently lacking. Here, we show that D. melanogaster females eject male ejaculates from the uterus 1-6 hr after mating with a stereotypic behavior regulated by a brain signaling pathway composed of diuretic hormone 44 (Dh44), a neuropeptide related to vertebrate corticotropin-releasing factor (CRF), and its receptor, Dh44R1. Suppression of Dh44 signals in the brain expedites sperm ejection from the uterus, resulting in marked reduction of sperm in the storage organs and decreased fecundity, whereas enhancement of Dh44 signals delays sperm expulsion. The Dh44 function was mapped to six neurons located in the pars intercerebralis of the brain together with a small subset of Dh44R1 neurons that express the sex-specific transcription factor doublesex. This study identifies a neuronal pathway by which females can control sperm retention and storage and provides new insight into how the female might exercise post-copulatory sexual selection. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Foellmer, Matthias W; Fairbairn, Daphne J
2005-02-01
Mate search plays a central role in hypotheses for the adaptive significance of extreme female-biased sexual size dimorphism (SSD) in animals. Spiders (Araneae) are the only free-living terrestrial taxon where extreme SSD is common. The "gravity hypothesis" states that small body size in males is favoured during mate search in species where males have to climb to reach females, because body length is inversely proportional to achievable speed on vertical structures. However, locomotive performance of males may also depend on relative leg length. Here we examine selection on male body size and leg length during mate search in the highly dimorphic orb-weaving spider Argiope aurantia, using a multivariate approach to distinguish selection targeted at different components of size. Further, we investigate the scaling relationships between male size and energy reserves, and the differential loss of reserves. Adult males do not feed while roving, and a size-dependent differential energy storage capacity may thus affect male performance during mate search. Contrary to predictions, large body size was favoured in one of two populations, and this was due to selection for longer legs. Male size was not under selection in the second population, but we detected direct selection for longer third legs. Males lost energy reserves during mate search, but this was independent of male size and storage capacity scaled isometrically with size. Thus, mate search is unlikely to lead to selection for small male size, but the hypothesis that relatively longer legs in male spiders reflect a search-adapted morphology is supported.
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Ekechukwu, Nkiru E.; Baeshen, Rowida; Traorè, Sékou F.; Coulibaly, Mamadou; Diabate, Abdoulaye; Catteruccia, Flaminia; Tripet, Frédéric
2015-01-01
The success of vector control strategies aiming to decrease disease transmission via the release of sterile or genetically-modified male mosquitoes critically depends on mating between laboratory-reared males and wild females. Unfortunately, mosquito colonization, laboratory rearing, and genetic manipulations can all negatively affect male competitiveness. Heterosis is commonly used to produce domestic animals with enhanced vigor and homogenous genetic background and could therefore potentially improve the mating performance of mass-reared male mosquitoes. Here, we produced enhanced hybrid males of the malaria mosquito Anopheles coluzzii by crossing two strains colonized >35 and 8 years ago. We compared the amount of sperm and mating plug proteins they transferred to females, as well as their insemination rate, reproductive success and longevity under various experimental conditions. Across experiments, widespread adaptations to laboratory mating were detected in the older strain. In large-group mating experiments, no overall hybrid advantage in insemination rates and the amount of sperm and accessory gland proteins transferred to females was detected. Despite higher sperm activity, hybrid males did not appear more fecund. However, individual-male mating and laboratory-swarm experiments revealed that hybrid males, while inseminating fewer females than older inbred males, were significantly more fertile, producing larger mating plugs and drastically increasing female fecundity. Heterotic males also showed increased longevity. These results validate the use of heterosis for creating hybrid males with improved fitness from long-established inbred laboratory strains. Therefore, this simple approach could facilitate disease control strategies based on male mosquito releases with important ultimate benefits to human health. PMID:26497140
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Still and Moving Image Evidences for Mating of Echinococcus granulosus Reared in Culture Media.
Mohammadzadeh, Tahereh; Sadjjadi, Seyed Mahmoud; Rahimi, Hamidreza
2014-03-01
Echinococcus granulosus cultivation is very important for improvement of different aspect of medical and veterinary researches. Despite many advances in this case, there is a missing link for in vitro life cycle of adult worms and it is fertilization. Regarding the researchers' observations, self-fertilization can be done in worms living in dog intestine, but despite all sorts of experimental techniques, this phenomenon has never been observed in reared worms in culture media. Furthermore, cross fertilization has not been observed in vitro and even in parasites with dog intestinal origin; although it theoretically is possible. During a follow-up of cultivated adult worms, evidences of behaviors similar to self-mating (Type 2) and cross-mating were observed in our lab which will be presented here. Protoscoleces were aseptically removed from sheep hydatid cysts, washed twice with PBS and then cultivated in S.10E.H culture medium. The stages of parasite growth were observed using an inverted microscope for two months and all stages and behaviors were microscopically photographed. Different movies have also been made from these behavioral features. After around 55 days post cultivation, some evidences of behaviors similar to self-mating (Type 2) and cross-mating were observed in some of the mature adult worms. However, fertile eggs in these parasites have never been observed. Regarding the above observations, these parasites show tendency to unsuccessful self-mating/fertilization (type 2) which failure could be due to anatomical position and physiological maturation. Also lack of suitable conditions for self-fertilization causes the worms try to do unsuccessful cross- mating/fertilization in culture media.
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The efficiency of close inbreeding to reduce genetic adaptation to captivity
Theodorou, K; Couvet, D
2015-01-01
Although ex situ conservation is indispensable for thousands of species, captive breeding is associated with negative genetic changes: loss of genetic variance and genetic adaptation to captivity that is deleterious in the wild. We used quantitative genetic individual-based simulations to model the effect of genetic management on the evolution of a quantitative trait and the associated fitness of wild-born individuals that are brought to captivity. We also examined the feasibility of the breeding strategies under a scenario of a large number of loci subject to deleterious mutations. We compared two breeding strategies: repeated half-sib mating and a method of minimizing mean coancestry (referred to as gc/mc). Our major finding was that half-sib mating is more effective in reducing genetic adaptation to captivity than the gc/mc method. Moreover, half-sib mating retains larger allelic and adaptive genetic variance. Relative to initial standing variation, the additive variance of the quantitative trait increased under half-sib mating during the sojourn in captivity. Although fragmentation into smaller populations improves the efficiency of the gc/mc method, half-sib mating still performs better in the scenarios tested. Half-sib mating shows two caveats that could mitigate its beneficial effects: low heterozygosity and high risk of extinction when populations are of low fecundity and size and one of the following conditions are met: (i) the strength of selection in captivity is comparable with that in the wild, (ii) deleterious mutations are numerous and only slightly deleterious. Experimental validation of half-sib mating is therefore needed for the advancement of captive breeding programs. PMID:25052417
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A potential mate influences reproductive development in female, but not male, pine siskins.
Watts, Heather E; Edley, Bruce; Hahn, Thomas P
2016-04-01
The role of photoperiod in avian reproductive timing has been well studied, and we are increasingly recognizing the roles of other environmental cues such as social cues. However, few studies have evaluated the extent to which males and females of the same species respond similarly to the same type of cue. Moreover, previous studies have rarely examined how variation in the quality or nature of a given social cue might modulate its effect. Here, we examine the sensitivity of male and female pine siskins (Spinus pinus) to a potential mate as a stimulatory cue for gonadal recrudescence, and we investigate whether variation in the relationship between a bird and its potential mate modulates the effect of that potential mate. Birds were initially housed without opposite sex birds on a 12L:12D photoperiod with ad libitum food. After gonadal recrudescence had begun males and females were randomly paired with an opposite sex bird or housed alone. An additional group of males was paired with estradiol-implanted females. In males, these social treatments had no effect on testis length, cloacal protuberance length, luteinizing hormone (LH) levels, or testosterone levels. In females, presence of a potential mate had a significant and positive effect on ovary score, defeathering of the brood patch, and LH levels. Among paired birds, the degree of affiliation within a pair corresponded to the extent of reproductive development in females, but not males. Thus, reproductive timing in females appears to be sensitive to both the presence of a potential mate and her relationship with him. Copyright © 2016 Elsevier Inc. All rights reserved.
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A potential mate influences reproductive development in female, but not male, pine siskins
Watts, Heather E.; Edley, Bruce; Hahn, Thomas P.
2016-01-01
The role of photoperiod in avian reproductive timing has been well studied, and we are increasingly recognizing the roles of other environmental cues such as social cues. However, few studies have evaluated the extent to which males and females of the same species respond similarly to the same type of cue. Moreover, previous studies have rarely examined how variation in the quality or nature of a given social cue might modulate its effect. Here, we examine the sensitivity of male and female pine siskins (Spinus pinus) to a potential mate as a stimulatory cue for gonadal recrudescence, and we investigate whether variation in the relationship between a bird and its potential mate modulates the effect of that potential mate. Birds were initially housed without opposite sex birds on a 12L:12D photoperiod with ad libitum food. After gonadal recrudescence had begun males and females were randomly paired with an opposite sex bird or housed alone. An additional group of males was paired with estradiol-implanted females. In males, these social treatments had no effect on testis length, cloacal protuberance length, luteinizing hormone (LH) levels, or testosterone levels. In females, presence of a potential mate had a significant and positive effect on ovary score, defeathering of the brood patch, and LH levels. Among paired birds, the degree of affiliation within a pair corresponded to the extent of reproductive development in females, but not males. Thus, reproductive timing in females appears to be sensitive to both the presence of a potential mate and her relationship with him. PMID:26836771
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Reduced population size does not affect the mating strategy of a vulnerable and endemic seabird
NASA Astrophysics Data System (ADS)
Nava, Cristina; Neves, Verónica C.; Andris, Malvina; Dubois, Marie-Pierre; Jarne, Philippe; Bolton, Mark; Bried, Joël
2017-12-01
Bottleneck episodes may occur in small and isolated animal populations, which may result in decreased genetic diversity and increased inbreeding, but also in mating strategy adjustment. This was evaluated in the vulnerable and socially monogamous Monteiro's Storm-petrel Hydrobates monteiroi, a seabird endemic to the Azores archipelago which has suffered a dramatic population decline since the XVth century. To do this, we conducted a genetic study (18 microsatellite markers) in the population from Praia islet, which has been monitored over 16 years. We found no evidence that a genetic bottleneck was associated with this demographic decline. Monteiro's Storm-petrels paired randomly with respect to genetic relatedness and body measurements. Pair fecundity was unrelated to genetic relatedness between partners. We detected only two cases of extra-pair parentage associated with an extra-pair copulation (out of 71 offspring). Unsuccessful pairs were most likely to divorce the next year, but genetic relatedness between pair mates and pair breeding experience did not influence divorce. Divorce enabled individuals to improve their reproductive performances after re-mating only when the new partner was experienced. Re-pairing with an experienced partner occurred more frequently when divorcees changed nest than when they retained their nest. This study shows that even in strongly reduced populations, genetic diversity can be maintained, inbreeding does not necessarily occur, and random pairing is not risky in terms of pair lifetime reproductive success. Given, however, that we found no clear phenotypic mate choice criteria, the part played by non-morphological traits should be assessed more accurately in order to better understand seabird mating strategies.
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Prevalence and intensity of nematode parasites in Wisconsin ermine.
Dubay, Shelli; Buchholz, Matthew J; Lisiecki, Robert; Huspeni, Todd; Ginnett, Tim; Haen, Luke; Borsdorf, Phil
2014-10-01
In the midwestern United States, ermine ( Mustela erminea ) are economically important because they are legally harvested for pelts. Information on parasites of ermine is lacking, and the effects that nematode parasites have on body condition of ermine hosts are unknown. We identified Skrjabingylus nasicola and Filaroides martis in ermine trapped from 2007 to 2013 from 6 counties in Wisconsin. Small mammals, commonly consumed by ermine, serve as paratenic hosts for both parasites. Our goal was to identify how age and sex of ermine, along with year, influence nematode parasitism. We also investigated how infection affected body condition for male and female ermine using body mass standardized by length as an index of body condition. We commonly found S. nasicola and F. martis in male and female ermine, but both prevalence and intensity of infection were higher for males. Relative to juveniles (<1 yr), adult (>1 yr) male ermine did not exhibit significantly higher intensity or prevalence of either parasite. We found that body condition was not compromised by infection for either sex, and intensity of S. nasicola and prevalence of F. martis were highest during the 2010-2011 trapping season. Of the 6 yr studied, precipitation was highest during the summer before the 2010-2011 season, and increased precipitation can cause increases in populations of gastropod intermediate hosts. We think that several distinct natural history components, namely, mating structure, diet, and metabolic rate, influence nematode parasitism in ermine.
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An Overview of the Function and Maintenance of Sexual Reproduction in Dikaryotic Fungi
Wallen, R. M.; Perlin, Michael H.
2018-01-01
Sexual reproduction likely evolved as protection from environmental stresses, specifically, to repair DNA damage, often via homologous recombination. In higher eukaryotes, meiosis and the production of gametes with allelic combinations different from parental type provides the side effect of increased genetic variation. In fungi it appears that while the maintenance of meiosis is paramount for success, outcrossing is not a driving force. In the subkingdom Dikarya, fungal members are characterized by existence of a dikaryon for extended stages within the life cycle. Such fungi possess functional or, in some cases, relictual, loci that govern sexual reproduction between members of their own species. All mating systems identified so far in the Dikarya employ a pheromone/receptor system for haploid organisms to recognize a compatible mating partner, although the paradigm in the Ascomycota, e.g., Saccharomyces cerevisiae, is that genes for the pheromone precursor and receptor are not found in the mating-type locus but rather are regulated by its products. Similarly, the mating systems in the Ascomycota are bipolar, with two non-allelic idiomorphs expressed in cells of opposite mating type. In contrast, for the Basidiomycota, both bipolar and tetrapolar mating systems have been well characterized; further, at least one locus directly encodes the pheromone precursor and the receptor for the pheromone of a different mating type, while a separate locus encodes proteins that may regulate the first locus and/or additional genes required for downstream events. Heterozygosity at both of two unlinked loci is required for cells to productively mate in tetrapolar systems, whereas in bipolar systems the two loci are tightly linked. Finally, a trade-off exists in wild fungal populations between sexual reproduction and the associated costs, with adverse conditions leading to mating. For fungal mammal pathogens, the products of sexual reproduction can be targets for the host immune system. The opposite appears true for phytopathogenic fungi, where mating and pathogenicity are inextricably linked. Here, we explore, compare, and contrast different strategies used among the Dikarya, both saprophytic and pathogenic fungi, and highlight differences between pathogens of mammals and pathogens of plants, providing context for selective pressures acting on this interesting group of fungi. PMID:29619017
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Context matters: sexual signaling loss in digital organisms
Weigel, Emily G; Testa, Nicholas D; Peer, Alex; Garnett, Sara C
2015-01-01
Sexual signals are important in attracting and choosing mates; however, these signals and their associated preferences are often costly and frequently lost. Despite the prevalence of signaling system loss in many taxa, the factors leading to signal loss remain poorly understood. Here, we test the hypothesis that complexity in signal loss scenarios is due to the context-dependent nature of the many factors affecting signal loss itself. Using the Avida digital life platform, we evolved 50 replicates of ∼250 lineages, each with a unique combination of parameters, including whether signaling is obligate or facultative; genetic linkage between signaling and receiving genes; population size; and strength of preference for signals. Each of these factors ostensibly plays a crucial role in signal loss, but was found to do so only under specific conditions. Under obligate signaling, genetic linkage, but not population size, influenced signal loss; under facultative signaling, genetic linkage does not have significant influence. Somewhat surprisingly, only a total loss of preference in the obligate signaling populations led to total signal loss, indicating that even a modest amount of preference is enough to maintain signaling systems. Strength of preference proved to be the strongest single force preventing signal loss, as it consistently overcame the potential effects of drift within our study. Our findings suggest that signaling loss is often dependent on not just preference for signals, population size, and genetic linkage, but also whether signals are required to initiate mating. These data provide an understanding of the factors (and their interactions) that may facilitate the maintenance of sexual signals. PMID:26380700
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Janes, J K; Roe, A D; Rice, A V; Gorrell, J C; Coltman, D W; Langor, D W; Sperling, F A H
2016-01-01
An understanding of mating systems and fine-scale spatial genetic structure is required to effectively manage forest pest species such as Dendroctonus ponderosae (mountain pine beetle). Here we used genome-wide single-nucleotide polymorphisms to assess the fine-scale genetic structure and mating system of D. ponderosae collected from a single stand in Alberta, Canada. Fine-scale spatial genetic structure was absent within the stand and the majority of genetic variation was best explained at the individual level. Relatedness estimates support previous reports of pre-emergence mating. Parentage assignment tests indicate that a polygamous mating system better explains the relationships among individuals within a gallery than the previously reported female monogamous/male polygynous system. Furthermore, there is some evidence to suggest that females may exploit the galleries of other females, at least under epidemic conditions. Our results suggest that current management models are likely to be effective across large geographic areas based on the absence of fine-scale genetic structure. PMID:26286666
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Ovarian fluid allows directional cryptic female choice despite external fertilization
Alonzo, Suzanne H.; Stiver, Kelly A.; Marsh-Rollo, Susan E.
2016-01-01
In species with internal fertilization, females can favour certain males over others, not only before mating but also within the female's reproductive tract after mating. Here, we ask whether such directional post-mating (that is, cryptic) female mate choice can also occur in species with external fertilization. Using an in vitro sperm competition experiment, we demonstrate that female ovarian fluid (ovarian fluid) changes the outcome of sperm competition by decreasing the importance of sperm number thereby increasing the relative importance of sperm velocity. We further show that ovarian fluid does not differentially affect sperm from alternative male phenotypes, but generally enhances sperm velocity, motility, straightness and chemoattraction. Under natural conditions, female ovarian fluid likely increases the paternity of the preferred parental male phenotype, as these males release fewer but faster sperm. These results imply females have greater control over fertilization and potential to exert selection on males in species with external fertilization than previously thought possible. PMID:27529581
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Frye, Cheryl A.; Rhodes, Madeline E.
2013-01-01
Background The progesterone (P4 ) metabolite, 5α-pregnan-3α-ol-20-one (3α,5α-THP), acts in the midbrain ventral tegmental area (VTA) to modulate the intensity and duration of lordosis. 3α,5α-THP can also have anti-anxiety and anti-stress effects in part through actions in the hippocampus. Separate reports indicate that manipulating 3α,5α-THP levels in the VTA or hippocampus respectively can influence lordosis and affective behavior. 3α,5α-THP levels can also be altered by behavioral experiences, such as mating or swim stress. Whether endogenous levels of 3α,5α-THP modulate and/or are increased in response to affective and/or reproductively-relevant behaviors was investigated. Methods In Experiment 1, rats in behavioral estrus or diestrus were individually tested sequentially in the open field, elevated plus maze, partner preference, social interaction, and paced mating tasks and levels of 17 β-estradiol (E2), P4, dihydroprogesterone (DHP), and 3α,5α-THP in serum, midbrain, hippocampus, diencephalon, and cortex were examined. In Experiments 2 and 3, rats in behavioral estrus or diestrus, were individually tested in the battery indicated above, with, or without, paced mating and tissues were collected immediately after testing for later assessment of endocrine measures. Results In Experiment 1, behavioral estrous, compared to diestrous, rats demonstrated more exploratory, anti-anxiety, social, and reproductive behaviors, and had higher levels of E2 and progestins in serum, midbrain, hippocampus, diencephalon, and cortex. In Experiment 2, in midbrain and hippocampus, levels of 3α,5α-THP and its precursor DHP were increased among rats in behavioral estrus that were mated. In diencephalon, and cortex, DHP levels were increased by mating. In Experiment 3, in midbrain, levels of 3α,5α-THP and its precursor DHP were increased among diestrous rats that were tested in the behavioral battery with mating as compared to those tested in the behavioral battery without mating. Conclusions Increased levels of 3α,5α-THP in behavioral estrus versus diestrous rats are associated with enhanced exploratory, anti-anxiety, social, and reproductive behaviors. Rats in behavioral estrus that are mated have further increases in 3α,5α-THP and/or DHP levels in midbrain, hippocampus, diencephalon, and cortex than do non-mated rats in behavioral estrus, whereas diestrous rats only show 3α,5α-THP increases in midbrain in response to behavioral testing that included mating. PMID:17028418
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The truthful signalling hypothesis: an explicit general equilibrium model.
Hausken, Kjell; Hirshleifer, Jack
2004-06-21
In mating competition, the truthful signalling hypothesis (TSH), sometimes known as the handicap principle, asserts that higher-quality males signal while lower-quality males do not (or else emit smaller signals). Also, the signals are "believed", that is, females mate preferentially with higher-signalling males. Our analysis employs specific functional forms to generate analytic solutions and numerical simulations that illuminate the conditions needed to validate the TSH. Analytic innovations include: (1) A Mating Success Function indicates how female mating choices respond to higher and lower signalling levels. (2) A congestion function rules out corner solutions in which females would mate exclusively with higher-quality males. (3) A Malthusian condition determines equilibrium population size as related to per-capita resource availability. Equilibria validating the TSH are achieved over a wide range of parameters, though not universally. For TSH equilibria it is not strictly necessary that the high-quality males have an advantage in terms of lower per-unit signalling costs, but a cost difference in favor of the low-quality males cannot be too great if a TSH equilibrium is to persist. And although the literature has paid less attention to these points, TSH equilibria may also fail if: the quality disparity among males is too great, or the proportion of high-quality males in the population is too large, or if the congestion effect is too weak. Signalling being unprofitable in aggregate, it can take off from a no-signalling equilibrium only if the trait used for signalling is not initially a handicap, but instead is functionally useful at low levels. Selection for this trait sets in motion a bandwagon, whereby the initially useful indicator is pushed by male-male competition into the domain where it does indeed become a handicap.
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Juan-Blasco, M; Sabater-Muñoz, B; Pla, I; Argilés, R; Castañera, P; Jacas, J A; Ibáñez-Gual, M V; Urbaneja, A
2014-04-01
Area-wide sterile insect technique (SIT) programs assume that offspring reduction of the target population correlates with the mating success of the sterile males released. However, there is a lack of monitoring tools to prove the success of these programs in real-time. Field-cage tests were conducted under the environmental conditions of the Mediterranean coast of Spain to estimate: (a) the mating success of sterile Vienna-8 (V8) Ceratitis capitata males using molecular markers and (b) their efficacy to reduce C. capitata populations under six release ratios of wild females to wild males to V8 males (1:0:0, 1:1:0, 1:1:1, 1:1:5, 1:1:10, and 1:1:20). Statistical models were developed to predict: (a) the number of females captured in traps, (b) sperm ID (sterile or not) in spermathecae of the trapped females, and (c) the viable offspring produced, using release ratio and temperature as predictors. The number of females captured was affected by relative humidity. However, its influence in the model was low. Female captures were significantly higher in ratios 1:0:0 compared to ratios where V8 males were released. The proportion of V8 sperm in spermathecae increased with temperature and with the number of V8 males released, but leveled off between ratios 1:1:10 and 1:1:20. In all seasons, except winter (no offspring), viable offspring increased with temperature and was lowest for ratio 1:1:20. For the first time, a strong negative relationship between proportion of V8 sperm detected by molecular tools and C. capitata offspring was established. The models obtained should contribute to enhance the efficacy of SIT programs against this pest.
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Host mating system and the spread of a disease-resistant allele in a population
DeAngelis, D.L.; Koslow, Jennifer M.; Jiang, J.; Ruan, S.
2008-01-01
The model presented here modifies a susceptible-infected (SI) host-pathogen model to determine the influence of mating system on the outcome of a host-pathogen interaction. Both deterministic and stochastic (individual-based) versions of the model were used. This model considers the potential consequences of varying mating systems on the rate of spread of both the pathogen and resistance alleles within the population. We assumed that a single allele for disease resistance was sufficient to confer complete resistance in an individual, and that both homozygote and heterozygote resistant individuals had the same mean birth and death rates. When disease invaded a population with only an initial small fraction of resistant genes, inbreeding (selfing) tended to increase the probability that the disease would soon be eliminated from a small population rather than become endemic, while outcrossing greatly increased the probability that the population would become extinct due to the disease.
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Sperm as moderators of environmentally induced paternal effects in a livebearing fish.
Evans, Jonathan P; Lymbery, Rowan A; Wiid, Kyle S; Rahman, Md Moshiur; Gasparini, Clelia
2017-04-01
Until recently, paternal effects-the influence of fathers on their offspring due to environmental factors rather than genes-were largely discarded or assumed to be confined to species exhibiting paternal care. It is now recognized that paternal effects can be transmitted through the ejaculate, but unambiguous evidence for them is scarce, because it is difficult to isolate effects operating via changes to the ejaculate from maternal effects driven by female mate assessment. Here, we use artificial insemination to disentangle mate assessment from fertilization in guppies, and show that paternal effects can be transmitted to offspring exclusively via ejaculates. We show that males fed reduced diets produce poor-quality sperm and that offspring sired by such males (via artificial insemination) exhibit reduced body size at birth. These findings may have important implications for the many mating systems in which environmentally induced changes in ejaculate quality have been reported. © 2017 The Author(s).
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Lietze, Verena-Ulrike; Geden, Christopher J.; Blackburn, Patrick; Boucias, Drion G.
2007-01-01
Pathological studies demonstrated that the salivary gland hypertrophy virus of houseflies (MdSGHV) shuts down reproduction in infected females. The mechanism that underlay the disruption of reproduction functioned on several levels. Females infected at the previtellogenic stage did not produce eggs, reflecting a block in the gonadotropic cycle. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis of hemolymph samples demonstrated that MdSGHV infection reduced the levels of both the female-specific hexamerin and egg yolk proteins. Furthermore, reverse transcriptase quantitative real-time PCR data demonstrated that infection blocked hexamerin and yolk protein gene transcription. When females were allowed to develop eggs prior to infection (postvitellogenic stage), the outcome of mating attempts depended upon when mating took place. If egg-containing, virus-infected females were mated within 24 h of infection, they copulated and deposited a single batch of fertilized eggs. However, if mating was delayed for a longer period, the egg-containing females refused to copulate with healthy males. Both of these results suggested that a virus-induced signal influenced the central nervous system, shutting down female receptivity and egg production. All experiments demonstrated that MdSGHV-infected males did not display azoospermia and were fertile. Both healthy females mated with infected males, and the resulting F1 progeny were free of salivary gland hypertrophy symptoms, which suggests that the virus is not sexually or vertically transmitted. PMID:17827327
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High estradiol and low progesterone are associated with high assertiveness in women.
Blake, Khandis R; Bastian, Brock; O'Dean, Siobhan M; Denson, Thomas F
2017-01-01
Sexual selection theory posits that women are more selective than men are when choosing a mate. This evolutionary theory suggests that "choosiness" increases during the fertile window because the costs and benefits of mate selection are highest when women are likely to conceive. Little research has directly investigated reproductive correlates of choice assertion. To address this gap, in the present research we investigated whether fertility, estradiol, and progesterone influenced general assertiveness in women. We recruited 98 naturally cycling, ethnically diverse women. Using a within-subjects design and ovarian hormone concentrations at fertile and non-fertile menstrual cycle phases, we measured implicit assertiveness and self-reported assertive behavior. To see if fertility-induced high assertiveness was related to increased sexual motivation, we also measured women's implicit sexual availability and interest in buying sexy clothes. Results showed that high estradiol and low progesterone predicted higher assertiveness. Sexual availability increased during periods of high fertility. Low progesterone combined with high estradiol predicted greater interest in buying sexy clothes. Results held when controlling for individual differences in mate value and sociosexual orientation. Our findings support the role of fluctuating ovarian hormones in the expression and magnitude of women's assertiveness. High assertiveness during the fertile window may be a psychological adaptation that promotes mate selectivity and safeguards against indiscriminate mate choice when conception risk is highest. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Cryptic sexual conflict in gift-giving insects: chasing the chase-away.
Sakaluk, Scott K; Avery, Rachel L; Weddle, Carie B
2006-01-01
The chase-away model of sexual selection posits that elaborate male sexual displays arise because they exploit preexisting biases in females' sensory systems and induce females to mate in a suboptimal manner. An essential element of this hypothesis is that such manipulation should quickly lead to female resistance to male displays. Nuptial food gifts may be a frequent conduit by which males attempt to influence the mating behavior of females against females' own reproductive interests. In decorated crickets Gryllodes sigillatus, such inducements come in the form of a spermatophylax, a gelatinous mass forming part of the male's spermatophore and consumed by the female after mating. We conducted experiments in which spermatophylaxes obtained from male G. sigillatus were offered as novel food gifts to females of a non-gift-giving species (Acheta domesticus) having no evolutionary history of spermatophylax consumption. Female A. domesticus that were allowed to consume the spermatophylax took significantly longer to remate than when given no such opportunity. In contrast, when female G. sigillatus were prevented from consuming their partners' nuptial gifts, there was no difference in their propensity to remate relative to females permitted to consume a food gift after mating. These results suggest that the spermatophylax synthesized by male G. sigillatus contains substances designed to inhibit the sexual receptivity of their mates but that female G. sigillatus have evolved reduced responsiveness to these substances.
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Olson, V.A; Liker, A; Freckleton, R.P; Székely, T
2007-01-01
Parents often conflict over how much care to provide to their offspring. This conflict is expected to produce a negative relationship between male and female parental care, the strength of which may be mediated by both ecological and life-history variables. Previous studies have observed such trade-offs, but it is not known how generally they occur. Traditional views of sexual conflict place great importance on ecological factors in determining levels of parental care, whereas alternative views propose that the key determinant is mating opportunity. We carried out a broad-scale comparative study of parental conflict using 193 species from 41 families of birds. Using phylogenetic comparative analysis, we establish the generality of intersexual parental care conflict. We also show that parental conflict, as indicated by the disparity in care between the male and the female, depends on offspring development and mating opportunities, since in precocial species both males and females responded to increased mating opportunities. Altricial birds, however, failed to show these relationships. We also found little influence of breeding climate on parental conflict. Taken together, our results suggest that sexual conflict is a key element in the evolution of parental care systems. They also support the view that the major correlates of the intersexual conflict are mating opportunities for both sexes, rather than the breeding environment. PMID:18029303
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Clark, Ann S; Kelton, Megan C; Guarraci, Fay A; Clyons, Erika Q
2004-05-01
A series of experiments was conducted to determine the contributions of hormonal status, test condition, and sexual experience to the display of partner preference by female rats. Preference for a sexually active male rat over a sexually receptive female rat was assessed in independent groups of female rats tested in a condition limiting physical contact (No Contact) and a condition allowing for sexual interaction (Contact). Although hormonal status and test condition influenced the preference for a sexually active male, repeated testing and sexual experience had no effect. Experiment 1 demonstrated that independent of test condition, preference for the male is stronger in estrogen- and progesterone-primed rats than in rats receiving the vehicle. Moreover, independent of hormone condition, rats tested in the No Contact condition exhibit a stronger preference for the male than rats tested in the Contact condition, reflecting in part the active pacing of mating stimulation by sexually receptive rats tested in the Contact condition. Experiment 2 showed that the overall pattern of partner preference in proestrous and diestrous rats was similar to that observed in ovariectomized, estrogen- and progesterone-primed, and oil-treated rats, respectively. In Experiment 3, rats primed with estrogen alone did not exhibit a preference for the male even though fully receptive. Experiments 4 and 5 demonstrated that sexual experience does not affect the expression of preference for the male in estrogen- and progesterone-primed rats. The present findings demonstrate that the female rat's preference for the male is stable across repeated tests and is not affected by sexual experience. Our results also confirm that gonadal hormones influence the expression of a preference for a sexually active male versus a sexually receptive female and demonstrate that the magnitude of preference is modulated by test conditions.
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USDA-ARS?s Scientific Manuscript database
In an effort to determine whether tropical adaptation influences circulating concentrations of the growth-related hormone, insulin-like growth factor-I (IGF-I), 3-breed diallel matings were conducted using temperate Bos taurus (A; Angus), tropical Bos indicus (B; Brahman), and tropical Bos taurus (R...
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Martínez-Rivera, Carlos César; Gerhardt, H. Carl
2009-01-01
Senders and receivers influence dynamic characteristics of the signals used for mate attraction over different time scales. On a moment-to-moment basis, interactions among senders competing for a mate influence dynamic characteristics, whereas the preferences of receivers of the opposite gender exert an influence over evolutionary time. We observed and recorded the calling patterns of the bird-voiced treefrog Hyla avivoca, to assess how the dynamic characters of calls vary during interactions among groups of males in a chorus. This question was also addressed using playback experiments with males. Playback experiments with females showed how changes in dynamic call properties are likely to affect male mating success. Frogs calling in pairs, groups, or in response to playbacks produced longer calls than did isolated males. During call overlap, males often increased the duration of the silent interval (gaps) between the pulses of their calls so that the pulses of the calls of two neighbors interdigitated. This change resulted in increased variability of pulse rate, a traditionally static acoustic property; however, males also produced high proportions of non-overlapped calls in which variability in pulse rate was low and had species-typical values. Females preferred long calls to short and average-duration calls, and non-overlapped calls to overlapped calls. Given a choice between pairs of overlapped calls, females preferred pairs in which the proportion of overlap was low and pairs in which the pulses of such calls interdigitated completely. The observed patterns of vocal competition thus reflect the preferences of conspecific females, which have influenced the evolution of the calling behavior of H. avivoca. PMID:19789730
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Genetic determinants of mate recognition in Brachionus manjavacas (Rotifera)
Snell, Terry W; Shearer, Tonya L; Smith, Hilary A; Kubanek, Julia; Gribble, Kristin E; Welch, David B Mark
2009-01-01
Background Mate choice is of central importance to most animals, influencing population structure, speciation, and ultimately the survival of a species. Mating behavior of male brachionid rotifers is triggered by the product of a chemosensory gene, a glycoprotein on the body surface of females called the mate recognition pheromone. The mate recognition pheromone has been biochemically characterized, but little was known about the gene(s). We describe the isolation and characterization of the mate recognition pheromone gene through protein purification, N-terminal amino acid sequence determination, identification of the mate recognition pheromone gene from a cDNA library, sequencing, and RNAi knockdown to confirm the functional role of the mate recognition pheromone gene in rotifer mating. Results A 29 kD protein capable of eliciting rotifer male circling was isolated by high-performance liquid chromatography. Two transcript types containing the N-terminal sequence were identified in a cDNA library; further characterization by screening a genomic library and by polymerase chain reaction revealed two genes belonging to each type. Each gene begins with a signal peptide region followed by nearly perfect repeats of an 87 to 92 codon motif with no codons between repeats and the final motif prematurely terminated by the stop codon. The two Type A genes contain four and seven repeats and the two Type B genes contain three and five repeats, respectively. Only the Type B gene with three repeats encodes a peptide with a molecular weight of 29 kD. Each repeat of the Type B gene products contains three asparagines as potential sites for N-glycosylation; there are no asparagines in the Type A genes. RNAi with Type A double-stranded RNA did not result in less circling than in the phosphate-buffered saline control, but transfection with Type B double-stranded RNA significantly reduced male circling by 17%. The very low divergence between repeat units, even at synonymous positions, suggests that the repeats are kept nearly identical through a process of concerted evolution. Information-rich molecules like surface glycoproteins are well adapted for chemical communication and aquatic animals may have evolved signaling systems based on these compounds, whereas insects use cuticular hydrocarbons. Conclusion Owing to its critical role in mating, the mate recognition pheromone gene will be a useful molecular marker for exploring the mechanisms and rates of selection and the evolution of reproductive isolation and speciation using rotifers as a model system. The phylogenetic variation in the mate recognition pheromone gene can now be studied in conjunction with the large amount of ecological and population genetic data being gathered for the Brachionus plicatilis species complex to understand better the evolutionary drivers of cryptic speciation. PMID:19740420
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Genetic determinants of mate recognition in Brachionus manjavacas (Rotifera).
Snell, Terry W; Shearer, Tonya L; Smith, Hilary A; Kubanek, Julia; Gribble, Kristin E; Welch, David B Mark
2009-09-09
Mate choice is of central importance to most animals, influencing population structure, speciation, and ultimately the survival of a species. Mating behavior of male brachionid rotifers is triggered by the product of a chemosensory gene, a glycoprotein on the body surface of females called the mate recognition pheromone. The mate recognition pheromone has been biochemically characterized, but little was known about the gene(s). We describe the isolation and characterization of the mate recognition pheromone gene through protein purification, N-terminal amino acid sequence determination, identification of the mate recognition pheromone gene from a cDNA library, sequencing, and RNAi knockdown to confirm the functional role of the mate recognition pheromone gene in rotifer mating. A 29 kD protein capable of eliciting rotifer male circling was isolated by high-performance liquid chromatography. Two transcript types containing the N-terminal sequence were identified in a cDNA library; further characterization by screening a genomic library and by polymerase chain reaction revealed two genes belonging to each type. Each gene begins with a signal peptide region followed by nearly perfect repeats of an 87 to 92 codon motif with no codons between repeats and the final motif prematurely terminated by the stop codon. The two Type A genes contain four and seven repeats and the two Type B genes contain three and five repeats, respectively. Only the Type B gene with three repeats encodes a peptide with a molecular weight of 29 kD. Each repeat of the Type B gene products contains three asparagines as potential sites for N-glycosylation; there are no asparagines in the Type A genes. RNAi with Type A double-stranded RNA did not result in less circling than in the phosphate-buffered saline control, but transfection with Type B double-stranded RNA significantly reduced male circling by 17%. The very low divergence between repeat units, even at synonymous positions, suggests that the repeats are kept nearly identical through a process of concerted evolution. Information-rich molecules like surface glycoproteins are well adapted for chemical communication and aquatic animals may have evolved signaling systems based on these compounds, whereas insects use cuticular hydrocarbons. Owing to its critical role in mating, the mate recognition pheromone gene will be a useful molecular marker for exploring the mechanisms and rates of selection and the evolution of reproductive isolation and speciation using rotifers as a model system. The phylogenetic variation in the mate recognition pheromone gene can now be studied in conjunction with the large amount of ecological and population genetic data being gathered for the Brachionus plicatilis species complex to understand better the evolutionary drivers of cryptic speciation.
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Ladich, Friedrich
2014-10-01
Bony fishes have evolved a diversity of sound generating mechanisms and produce a variety of sounds. By contrast to sound generating mechanisms, which are lacking in several taxa, all fish species possess inner ears for sound detection. Fishes may also have various accessory structures such as auditory ossicles to improve hearing. The distribution of sound generating mechanisms and accessory hearing structures among fishes indicates that acoustic communication was not the driving force in their evolution. It is proposed here that different constraints influenced hearing and sound production during fish evolution, namely certain life history traits (territoriality, mate attraction) in the case of sound generating mechanisms, and adaptation to different soundscapes (ambient noise conditions) in accessory hearing structures (Ecoacoustical constraints hypothesis). Copyright © 2014 Elsevier Ltd. All rights reserved.
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Family feuds: social competition and sexual conflict in complex societies
Rubenstein, Dustin R.
2012-01-01
Darwin was initially puzzled by the processes that led to ornamentation in males—what he termed sexual selection—and those that led to extreme cooperation and altruism in complex animal societies—what was later termed kin selection. Here, I explore the relationships between sexual and kin selection theory by examining how social competition for reproductive opportunities—particularly in females—and sexual conflict over mating partners are inherent and critical parts of complex altruistic societies. I argue that (i) patterns of reproductive sharing within complex societies can drive levels of social competition and reproductive conflict not only in males but also in females living in social groups, and ultimately the evolution of female traits such as ornaments and armaments; (ii) mating conflict over female choice of sexual partners can influence kin structure within groups and drive the evolution of complex societies; and (iii) patterns of reproductive sharing and conflict among females may also drive the evolution of complex societies by influencing kin structure within groups. Ultimately, complex societies exhibiting altruistic behaviour appear to have only arisen in taxa where social competition over reproductive opportunities and sexual conflict over mating partners were low. Once such societies evolved, there were important selective feedbacks on traits used to regulate and mediate intra-sexual competition over reproductive opportunities, particularly in females. PMID:22777018
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Presenting Your Best Self(ie): The Influence of Gender on Vertical Orientation of Selfies on Tinder
Sedgewick, Jennifer R.; Flath, Meghan E.; Elias, Lorin J.
2017-01-01
When taking a self-portrait or “selfie” to display in an online dating profile, individuals may intuitively manipulate the vertical camera angle to embody how they want to be perceived by the opposite sex. Concepts from evolutionary psychology and grounded cognition suggest that this manipulation can provide cues of physical height and impressions of power to the viewer which are qualities found to influence mate-selection. We predicted that men would orient selfies more often from below to appear taller (i.e., more powerful) than the viewer, and women, from an above perspective to appear shorter (i.e., less powerful). A content analysis was conducted which coded the vertical orientation of 557 selfies from profile pictures on the popular mobile dating application, Tinder. In general, selfies were commonly used by both men (54%) and women (90%). Consistent with our predictions, a gender difference emerged; men's selfies were angled significantly more often from below, whereas women's were angled more often from above. Our findings suggest that selfies presented in a mate-attraction context are intuitively or perhaps consciously selected to adhere to ideal mate qualities. Further discussion proposes that biological or individual differences may also facilitate vertical compositions of selfies. PMID:28484408
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Caddigan, Sara C; Pfenning, Alaina C; Sparkes, Timothy C
2017-01-01
The acanthocephalan Acanthocephalus dirus is a trophically transmitted parasite that modifies both the physiology and behavior of its intermediate host (isopod) prior to transmission to its definitive host (fish). Infected isopods often contain multiple A. dirus individuals and we examined the relationships between host sharing, body size, energy content, and host modification to determine if host sharing was costly and if these costs could influence the modification of host behavior (mating behavior). Using field-based measures of parasite energy content (glycogen, lipid) and parasite body size (volume), we showed that host sharing was costly in terms of energy content but not in terms of body size. Analysis of the predictors of host behavior revealed that energy content, and body size, were not predictors of host behavior. Of the variables examined, parasite intensity was the only predictor of host behavior. Hosts that contained more parasites were less likely to be modified (i.e., less likely to undergo mating suppression). We suggest that intraspecific competition influenced parasite energy content and that the costs associated with competition are likely to shape the strategy of growth and energy allocation adopted by the parasites. These costs did not appear to have a direct effect on the modification of host mating behavior.
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Family feuds: social competition and sexual conflict in complex societies.
Rubenstein, Dustin R
2012-08-19
Darwin was initially puzzled by the processes that led to ornamentation in males-what he termed sexual selection-and those that led to extreme cooperation and altruism in complex animal societies-what was later termed kin selection. Here, I explore the relationships between sexual and kin selection theory by examining how social competition for reproductive opportunities-particularly in females-and sexual conflict over mating partners are inherent and critical parts of complex altruistic societies. I argue that (i) patterns of reproductive sharing within complex societies can drive levels of social competition and reproductive conflict not only in males but also in females living in social groups, and ultimately the evolution of female traits such as ornaments and armaments; (ii) mating conflict over female choice of sexual partners can influence kin structure within groups and drive the evolution of complex societies; and (iii) patterns of reproductive sharing and conflict among females may also drive the evolution of complex societies by influencing kin structure within groups. Ultimately, complex societies exhibiting altruistic behaviour appear to have only arisen in taxa where social competition over reproductive opportunities and sexual conflict over mating partners were low. Once such societies evolved, there were important selective feedbacks on traits used to regulate and mediate intra-sexual competition over reproductive opportunities, particularly in females.
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Roulin, Alexandre
2016-05-01
The signalling function of melanin-based colouration is debated. Sexual selection theory states that ornaments should be costly to produce, maintain, wear or display to signal quality honestly to potential mates or competitors. An increasing number of studies supports the hypothesis that the degree of melanism covaries with aspects of body condition (e.g. body mass or immunity), which has contributed to change the initial perception that melanin-based colour ornaments entail no costs. Indeed, the expression of many (but not all) melanin-based colour traits is weakly sensitive to the environment but strongly heritable suggesting that these colour traits are relatively cheap to produce and maintain, thus raising the question of how such colour traits could signal quality honestly. Here I review the production, maintenance and wearing/displaying costs that can generate a correlation between melanin-based colouration and body condition, and consider other evolutionary mechanisms that can also lead to covariation between colour and body condition. Because genes controlling melanic traits can affect numerous phenotypic traits, pleiotropy could also explain a linkage between body condition and colouration. Pleiotropy may result in differently coloured individuals signalling different aspects of quality that are maintained by frequency-dependent selection or local adaptation. Colouration may therefore not signal absolute quality to potential mates or competitors (e.g. dark males may not achieve a higher fitness than pale males); otherwise genetic variation would be rapidly depleted by directional selection. As a consequence, selection on heritable melanin-based colouration may not always be directional, but mate choice may be conditional to environmental conditions (i.e. context-dependent sexual selection). Despite the interest of evolutionary biologists in the adaptive value of melanin-based colouration, its actual role in sexual selection is still poorly understood. © 2015 Cambridge Philosophical Society.
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Weber, Emanuel; Pinkse, Martijn W. H.; Bener-Aksam, Eda; Vellekoop, Michael J.; Verhaert, Peter D. E. M.
2012-01-01
We present a fully automated setup for performing in-line mass spectrometry (MS) analysis of conditioned media in cell cultures, in particular focusing on the peptides therein. The goal is to assess peptides secreted by cells in different culture conditions. The developed system is compatible with MS as analytical technique, as this is one of the most powerful analysis methods for peptide detection and identification. Proof of concept was achieved using the well-known mating-factor signaling in baker's yeast, Saccharomyces cerevisiae. Our concept system holds 1 mL of cell culture medium and allows maintaining a yeast culture for, at least, 40 hours with continuous supernatant extraction (and medium replenishing). The device's small dimensions result in reduced costs for reagents and open perspectives towards full integration on-chip. Experimental data that can be obtained are time-resolved peptide profiles in a yeast culture, including information about the appearance of mating-factor-related peptides. We emphasize that the system operates without any manual intervention or pipetting steps, which allows for an improved overall sensitivity compared to non-automated alternatives. MS data confirmed previously reported aspects of the physiology of the yeast-mating process. Moreover, matingfactor breakdown products (as well as evidence for a potentially responsible protease) were found. PMID:23091722
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Diller, Carolina; Fenster, Charles B
2016-07-01
Corolla chirality, the pinwheel arrangement of petals within a flower, is found throughout the core eudicots. In 15 families, different chiral type flowers (i.e., right or left rotated corolla) exist on the same plant, and this condition is referred to as unfixed/enantiomorphic corolla chirality. There are no investigations on the significance of unfixed floral chirality on directed pollen movement even though analogous mirror image floral designs, for example, enantiostyly, has evolved in response to selection to direct pollinator and pollen movement. Here, we examine the role of corolla chirality on directing pollen transfer, pollinator behavior, and its potential influence on disassortative mating. We quantified pollen transfer and pollinator behavior and movement for both right and left rotated flowers in two populations of Hypericum perforatum. In addition, we quantified the number of right and left rotated flowers at the individual level. Pollinators were indifferent to corolla chirality resulting in no difference in pollen deposition between right and left flowers. Corolla chirality had no effect on pollinator and pollen movement between and within chiral morphs. Unlike other mirror image floral designs, corolla chirality appears to play no role in promoting disassortative mating in this species.
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Preston, B T; Stevenson, I R; Pemberton, J M; Coltman, D W; Wilson, K
2003-03-22
Male contests for access to receptive females are thought to have selected for the larger male body size and conspicuous weaponry frequently observed in mammalian species. However, when females copulate with multiple males within an oestrus, male reproductive success is a function of both pre- and postcopulatory strategies. The relative importance of these overt and covert forms of sexual competition has rarely been assessed in wild populations. The Soay sheep mating system is characterized by male contests for mating opportunities and high female promiscuity. We find that greater horn length, body size and good condition each independently influence a male's ability to monopolize receptive females. For males with large horns at least, this behavioural success translates into greater siring success. Consistent with sperm-competition theory, we also find that larger testes are independently associated with both higher copulation rates and increased siring success. This advantage of larger testes emerges, and strengthens, as the number of oestrous females increases, as dominant males can no longer control access to them all. Our results thus provide direct quantitative evidence that male reproductive success in wild populations of mammals is dependent upon the relative magnitude of both overt contest competition and covert sperm competition.
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Zhang, Wei; Zhao, Fei; Hoffmann, Ary A.; Ma, Chun-Sen
2013-01-01
Extremely hot events (usually involving a few hours at extreme high temperatures in summer) are expected to increase in frequency in temperate regions under global warming. The impact of these events is generally overlooked in insect population prediction, since they are unlikely to cause widespread mortality, however reproduction may be affected by them. In this study, we examined such stress effects in the diamondback moth, Plutella xylostella. We simulated a single extreme hot day (maximum of 40°C lasting for 3, 4 or 5 h) increasingly experienced under field conditions. This event had no detrimental effects on immediate mortality, copulation duration, mating success, longevity or lifetime fecundity, but stressed females produced 21% (after 3 or 4 h) fewer hatched eggs because of a decline in the number and hatching success of eggs laid on the first two days. These negative effects on reproduction were no longer evident in the following days. Male heat exposure led to a similar but smaller effect on fertile egg production, and exposure extended pre-mating period in both sexes. Our results indicate that a single hot day can have detrimental effects on reproduction, particularly through maternal effects on egg hatching, and thereby influence the population dynamics of diamondback moth. PMID:24116081
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Bates, M L Shawn; Hofford, Rebeca S; Emery, Michael A; Wellman, Paul J; Eitan, Shoshana
2018-07-01
The association with opioid-abusing individuals or even the perception of opioid abuse by peers are risk factors for the initiation and escalation of abuse. Similarly, we demonstrated that morphine-treated animals housed with only morphine-treated animals (referred to as morphine only) acquire morphine conditioned place-preference (CPP) more readily than morphine-treated animals housed with drug-naïve animals (referred to as morphine cage-mates). However, the molecular mechanisms underlying these effects are still elusive. Mice received repeated morphine or saline while housed as saline only, morphine only, or cage-mates. Then, they were examined for the expression levels of D1 dopamine receptor (D1DR), D2 dopamine receptor (D2DR), dopamine transporter (DAT), oxytocin, and Arginine-vasopressin (AVP) in the striatum using qPCR. Additionally, we examined the effects of the AVP-V1b receptor antagonist, SSR149415, on the acquisition of morphine conditioned place-preference (CPP). Increased striatal expression of D1DR and AVP was observed in morphine only animals, but not morphine cage-mates. No significant effects were observed on the striatal expression of D2DR, DAT, or oxytocin. Antagonizing the AVP-V1b receptors decreased the acquisition of morphine CPP in the morphine only mice, but did not alter the acquisition of morphine CPP in the morphine cage-mate mice. Housing with drug-naïve animals protects against the increase in striatal expression of D1DR and AVP elicited by morphine exposure. Moreover, our studies suggest that the protective effect of housing with drug-naïve animals on the acquisition of morphine reward might be, at least partially, mediated by AVP. Copyright © 2018 Elsevier B.V. All rights reserved.
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Environmental Factors Can Influence Mitochondrial Inheritance in the Saccharomyces Yeast Hybrids
Hsu, Yu-Yi; Chou, Jui-Yu
2017-01-01
Mitochondria play a critical role in the generation of metabolic energy and are crucial for eukaryotic cell survival and proliferation. In most sexual eukaryotes, mitochondrial DNA (mtDNA) is inherited from only one parent in non-Mendelian inheritance in contrast to the inheritance of nuclear DNA. The model organism Saccharomyces cerevisiae is commonly used to study mitochondrial biology. It has two mating types: MATa and MATα. Previous studies have suggested that the mtDNA inheritance patterns in hybrid diploid cells depend on the genetic background of parental strains. However, the underlying mechanisms remain unclear. To elucidate the mechanisms, we examined the effects of environmental factors on the mtDNA inheritance patterns in hybrids obtained by crossing S. cerevisiae with its close relative S. paradoxus. The results demonstrated that environmental factors can influence mtDNA transmission in hybrid diploids, and that the inheritance patterns are strain dependent. The fitness competition assay results showed that the fitness differences can explain the mtDNA inheritance patterns under specific conditions. However, in this study, we found that fitness differences cannot fully be explained by mitochondrial activity in hybrids under stress conditions. PMID:28081193