Romantic preferences in Brazilian undergraduate students: from the short term to the long term.

PubMed

Castro, Felipe Nalon; de Araújo Lopes, Fívia

2011-09-01

A number of studies have described different preference patterns typically found for men and women when choosing romantic mates. These vary according to the involvement level expected in the relationship. Despite the number of investigations on the topic, one must be careful not to generalize because most studies use samples composed of North American university undergraduates. This study sought to determine if the preference patterns typically found in other countries also occur among Brazilian undergraduates. The importance of characteristics and modifications in preference patterns under gradually restrictive conditions was also investigated. In general, the results obtained suggest that the preferences found in a number of countries also occur in Brazil. In short-term relationships, men prioritize physical attributes, whereas personal traits gain importance when involvement increases. Women in short-term relationships value physical and personal traits, whereas in the long term, they emphasize personal characteristics and their mate's desire to acquire resources. Resource-related traits were less important than the other traits, and were more important for women than for men.

Testing synaptic plasticity in dynamic mate choice decisions: N-methyl d-aspartate receptor blockade disrupts female preference

PubMed Central

Ramsey, Mary E.; Vu, Wendy; Cummings, Molly E.

2014-01-01

Social behaviours such as mate choice require context-specific responses, often with evolutionary consequences. Increasing evidence indicates that the behavioural plasticity associated with mate choice involves learning. For example, poeciliids show age-dependent changes in female preference functions and express synaptic-plasticity-associated molecular markers during mate choice. Here, we test whether social cognition is necessary for female preference behaviour by blocking the central player in synaptic plasticity, NMDAR (N-methyl d-aspartate receptor), in a poeciliid fish, Xiphophorus nigrensis. After subchronic exposure to NMDAR antagonist MK-801, female preference behaviours towards males were dramatically reduced. Overall activity levels were unaffected, but there was a directional shift from ‘social’ behaviours towards neutral activity. Multivariate gene expression patterns significantly discriminated between females with normal versus disrupted plasticity processes and correlated with preference behaviours—not general activity. Furthermore, molecular patterns support a distinction between ‘preference’ (e.g. neuroserpin, neuroligin-3, NMDAR) and ‘sociality’ (isotocin and vasotocin) gene clusters, highlighting a possible conservation between NMDAR disruption and nonapeptides in modulating behaviour. Our results suggest that mate preference may involve greater social memory processing than overall sociality, and that poeciliid preference functions integrate synaptic-plasticity-oriented ‘preference’ pathways with overall sociality to invoke dynamic, context-specific responses towards favoured males and away from unfavoured males. PMID:24807251

The effect of time postexposure and sex on the horizontal transmission of Metarhizium brunneum conidia between Asian longhorned beetle (Coleoptera: Cerambycidae) mates.

PubMed

Ugine, Todd A; Peters, Kenlyn E; Gardescu, Sana; Hajek, Ann E

2014-12-01

A study using Metarhizium brunneum Petch fungal bands designed to improve delivery of conidia to adult Asian longhorned beetles, Anoplophora glabripennis (Motschulsky), was conducted to determine how a time delay between exposure to infective conidia and pairing of male and female beetles would affect the ability to successfully transfer lethal doses of conidia to a mate. We measured conidial load at the time of mate pairing (0, 4, 24, 48 h postexposure) and assessed its effect on beetle mortality. Conidial load per beetle decreased across the four sampling times, and there was no effect of beetle sex on conidial load. At all time periods postexposure, beetles that climbed across fungal bands carried enough conidia that at least some of their indirectly exposed mates died of mycosis. For indirectly exposed beetles, mortality decreased significantly as the time delay increased from 0 to 48 h, and this was independent of beetle sex. Median survival time was only 11.5 d for females indirectly exposed immediately after their mate had been exposed, but >3 wk when there was a 48-h delay before pairing. Generally, beetles exposed directly to fungal bands died faster than their indirectly exposed mates. In contrast to the pattern seen for indirectly exposed beetles, beetles exposed directly to fungal bands showed no change in survival times with a delay between exposure and pairing. Median survival times of exposed females and males were generally similar, at 10.5-12.5 d.

Patterns of mating in an insect-pollinated tree species in the Missouri Ozark Forest Ecosystem Project

Treesearch

Victoria J. Apsit; Rodney J. Dyer; Victoria L. Sork

2002-01-01

Contemporary gene flow is a major mechanism for the maintenance of genetic diversity. One component of gene flow is the mating system, which is a composite measure of selfing, mating with relatives, and outcrossing. Although both gene flow and mating patterns contribute to the ecological sustainability of populations, a focus of many forest management plans, these...

Mating patterns and post-mating isolation in three cryptic species of the Engystomops petersi species complex.

PubMed

Trillo, Paula A; Narvaez, Andrea E; Ron, Santiago R; Hoke, Kim L

2017-01-01

Determining the extent of reproductive isolation in cryptic species with dynamic geographic ranges can yield important insights into the processes that generate and maintain genetic divergence in the absence of severe geographic barriers. We studied mating patterns, propensity to hybridize in nature and subsequent fertilization rates, as well as survival and development of hybrid F1 offspring for three nominal species of the Engystomops petersi species complex in Yasuní National Park, Ecuador. We found at least two species in four out of six locations sampled, and 14.3% of the wild pairs genotyped were mixed-species (heterospecific) crosses. We also found reduced fertilization rates in hybrid crosses between E. petersi females and E. "magnus" males, and between E. "magnus" females and E. "selva" males but not in the reciprocal crosses, suggesting asymmetric reproductive isolation for these species. Larval development times decreased in F1 hybrid crosses compared to same species (conspecific) crosses, but we did not find significant reduction in larval survival or early metamorph survival. Our results show evidence of post-mating isolation for at least two hybrid crosses of the cryptic species we studied. The general decrease in fertilization rates in heterospecific crosses suggests that sexual selection and reinforcement might have not only contributed to the pattern of call variation and behavioral isolation we see between species today, but they may also contribute to further signal divergence and behavioral evolution, especially in locations where hybridization is common and fertilization success is diminished.

46 CFR 11.463 - General requirements for endorsements as master, mate (pilot), and apprentice mate (steersman) of...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false General requirements for endorsements as master, mate... Professional Requirements for Deck Officers § 11.463 General requirements for endorsements as master, mate... endorsements: (1) Master of towing vessels. (2) Master of towing vessels, limited. (3) Mate (pilot) of towing...

46 CFR 11.463 - General requirements for endorsements as master, mate (pilot), and apprentice mate (steersman) of...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false General requirements for endorsements as master, mate... Professional Requirements for Deck Officers § 11.463 General requirements for endorsements as master, mate... endorsements: (1) Master of towing vessels. (2) Master of towing vessels, limited. (3) Mate (pilot) of towing...

46 CFR 11.463 - General requirements for endorsements as master, mate (pilot), and apprentice mate (steersman) of...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false General requirements for endorsements as master, mate... Professional Requirements for Deck Officers § 11.463 General requirements for endorsements as master, mate... endorsements: (1) Master of towing vessels. (2) Master of towing vessels, limited. (3) Mate (pilot) of towing...

46 CFR 11.463 - General requirements for endorsements as master, mate (pilot), and apprentice mate (steersman) of...

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false General requirements for endorsements as master, mate... Professional Requirements for Deck Officers § 11.463 General requirements for endorsements as master, mate... endorsements: (1) Master of towing vessels. (2) Master of towing vessels, limited. (3) Mate (pilot) of towing...

Validation of Bateman's principles: a genetic study of sexual selection and mating patterns in the rough-skinned newt.

PubMed Central

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

On Variation of Polyandry in a Bush-Cricket, Metrioptera roeselii, in Northern Europe

PubMed Central

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.

Direct fitness benefits explain mate preference, but not choice, for similarity in heterozygosity levels.

PubMed

Zandberg, Lies; Gort, Gerrit; van Oers, Kees; Hinde, Camilla A

2017-10-01

Under sexual selection, mate preferences can evolve for traits advertising fitness benefits. Observed mating patterns (mate choice) are often assumed to represent preference, even though they result from the interaction between preference, sampling strategy and environmental factors. Correlating fitness with mate choice instead of preference will therefore lead to confounded conclusions about the role of preference in sexual selection. Here we show that direct fitness benefits underlie mate preferences for genetic characteristics in a unique experiment on wild great tits. In repeated mate preference tests, both sexes preferred mates that had similar heterozygosity levels to themselves, and not those with which they would optimise offspring heterozygosity. In a subsequent field experiment where we cross fostered offspring, foster parents with more similar heterozygosity levels had higher reproductive success, despite the absence of assortative mating patterns. These results support the idea that selection for preference persists despite constraints on mate choice. © 2017 The Authors Ecology Letters published by CNRS and John Wiley & Sons Ltd.

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.

Beyond magic traits: Multimodal mating cues in Heliconius butterflies.

PubMed

Mérot, Claire; Frérot, Brigitte; Leppik, Ene; Joron, Mathieu

2015-11-01

Species coexistence involves the evolution of reproductive barriers opposing gene flow. Heliconius butterflies display colorful patterns affecting mate choice and survival through warning signaling and mimicry. These patterns are called "magic traits" for speciation because divergent natural selection may promote mimicry shifts in pattern whose role as mating cue facilitates reproductive isolation. By contrast, between comimetic species, natural selection promotes pattern convergence. We addressed whether visual convergence interferes with reproductive isolation by testing for sexual isolation between two closely related species with similar patterns, H. timareta thelxinoe and H. melpomene amaryllis. Experiments with models confirmed visual attraction based on wing phenotype, leading to indiscriminate approach. Nevertheless, mate choice experiments showed assortative mating. Monitoring male behavior toward live females revealed asymmetry in male preference, H. melpomene males courting both species equally while H. timareta males strongly preferred conspecifics. Experiments with hybrid males suggested an important genetic component for such asymmetry. Behavioral observations support a key role for short-distance cues in determining male choice in H. timareta. Scents extracts from wings and genitalia revealed interspecific divergence in chemical signatures, and hybrid female scent composition was significantly associated with courtship intensity by H. timareta males, providing candidate chemical mating cues involved in sexual isolation. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Mating patterns and post-mating isolation in three cryptic species of the Engystomops petersi species complex

PubMed Central

Narvaez, Andrea E.; Ron, Santiago R.; Hoke, Kim L.

2017-01-01

Determining the extent of reproductive isolation in cryptic species with dynamic geographic ranges can yield important insights into the processes that generate and maintain genetic divergence in the absence of severe geographic barriers. We studied mating patterns, propensity to hybridize in nature and subsequent fertilization rates, as well as survival and development of hybrid F1 offspring for three nominal species of the Engystomops petersi species complex in Yasuní National Park, Ecuador. We found at least two species in four out of six locations sampled, and 14.3% of the wild pairs genotyped were mixed-species (heterospecific) crosses. We also found reduced fertilization rates in hybrid crosses between E. petersi females and E. “magnus” males, and between E. “magnus” females and E. “selva” males but not in the reciprocal crosses, suggesting asymmetric reproductive isolation for these species. Larval development times decreased in F1 hybrid crosses compared to same species (conspecific) crosses, but we did not find significant reduction in larval survival or early metamorph survival. Our results show evidence of post-mating isolation for at least two hybrid crosses of the cryptic species we studied. The general decrease in fertilization rates in heterospecific crosses suggests that sexual selection and reinforcement might have not only contributed to the pattern of call variation and behavioral isolation we see between species today, but they may also contribute to further signal divergence and behavioral evolution, especially in locations where hybridization is common and fertilization success is diminished. PMID:28388628

The evolution of sex roles in mate searching.

PubMed

Fromhage, Lutz; Jennions, Michael; Kokko, Hanna

2016-03-01

Searching for mates is a critical stage in the life cycle of most internally, and many externally, fertilizing species. Males usually invest more in this costly activity than females, but the reasons for this are poorly understood. Previous models have shown that female-biased parental investment, including anisogamy, does not by itself select for male-biased mate searching, so it requires additional explanations. Here, we correct and expand upon earlier models, and present two novel hypotheses that might explain the evolution of male-biased mate searching. The "carry-over hypothesis" states that females benefit less from searching if the associated costs affect other stages of the life cycle, rather than arising only while searching. It is relevant to the evolution of morphological traits that improve searching efficiency but are also expressed in other contexts. The "mating window hypothesis" states that females benefit less from searching if their life cycle includes intervals during which the exact timing of mating does not matter for the appropriate timing of reproduction (e.g., due to sperm storage or delayed embryo implantation). Such intervals are more likely to exist for females given the general pattern of greater female parental investment. Our models shed new light on classic arguments about sex role evolution. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Sperm competition games: the risk model can generate higher sperm allocation to virgin females.

PubMed

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.

A spatial genetic structure and effects of relatedness on mate choice in a wild bird population.

PubMed

Foerster, K; Valcu, M; Johnsen, A; Kempenaers, B

2006-12-01

Inbreeding depression, as commonly found in natural populations, should favour the evolution of inbreeding avoidance mechanisms. If natal dispersal, the first and probably most effective mechanism, does not lead to a complete separation of males and females from a common origin, a small-scale genetic population structure may result and other mechanisms to avoid inbreeding may exist. We studied the genetic population structure and individual mating patterns in blue tits (Parus caeruleus). The population showed a local genetic structure in two out of four years: genetic relatedness between individuals (estimated from microsatellite markers) decreased with distance. This pattern was mainly caused by immigrants to the study area; these, if paired with fellow immigrants, were more related than expected by chance. Since blue tits did not avoid inbreeding with their social partner, we examined if individuals preferred less related partners at later stages of the mate choice process. We found no evidence that females or males avoided inbreeding through extra-pair copulations or through mate desertion and postbreeding dispersal. Although the small-scale genetic population structure suggests that blue tits could use a simple rule of thumb to select less related mates, females did not generally prefer more distantly breeding extra-pair partners. However, the proportion of young fathered by an extra-pair male in mixed paternity broods depended on the genetic relatedness with the female. This suggests that there is a fertilization bias towards less related copulation partners and that blue tits are able to reduce the costs of inbreeding through a postcopulatory process.

Phylogenetic perspectives on the evolution of functional hermaphroditism in teleost fishes.

PubMed

Erisman, Brad E; Petersen, Christopher W; Hastings, Philip A; Warner, Robert R

2013-10-01

Hermaphroditism is taxonomically widespread among teleost fishes and takes on many forms including simultaneous, protogynous, and protandrous hermaphroditism, bidirectional sex change, and androdioecy. The proximate mechanisms that influence the timing, incidence, and forms of hermaphroditism in fishes are supported by numerous theoretical and empirical studies on their mating systems and sexual patterns, but few have examined aspects of sex-allocation theory or the evolution of hermaphroditism for this group within a strict phylogenetic context. Fortunately, species-level phylogenetic reconstructions of the evolutionary history of many lineages of fishes have emerged, providing opportunities for understanding fine-scale evolutionary pathways and transformations of sex allocation. Examinations of several families of fishes with adequate data on phylogeny, patterns of sex allocation, mating systems, and with some form of hermaphroditism reveal that the evolution and expression of protogyny and other forms of sex allocation show little evidence of phylogenetic inertia within specific lineages but rather are associated with particular mating systems in accordance with prevalent theories about sex allocation. Transformations from protogyny to gonochorism in groupers (Epinephelidae), seabasses (Serranidae), and wrasses and parrotfishes (Labridae) are associated with equivalent transformations in the structure of mating groups from spawning of pairs to group spawning and related increases in sperm competition. Similarly, patterns of protandry, androdioecy, simultaneous hermaphroditism, and bidirectional sex change in other lineages (Aulopiformes, Gobiidae, and Pomacentridae) match well with particular mating systems in accordance with sex-allocation theory. Unlike other animals and plants, we did not find evidence that transitions between hermaphroditism and gonochorism required functional intermediates. Two instances in which our general conclusions might not hold include the expression of protandry in the Sparidae and the distribution of simultaneous hermaphroditism. In the Sparidae, the association of hypothesized mating systems and patterns of sex allocation were not always consistent with the size-advantage model (SAM), in that certain protandric sparids show evidence of intense sperm competition that should favor the expression of gonochorism. In the other case, simultaneous hermaphroditism does not occur in some groups of monogamous fishes, which are similar in ecology to the hermaphroditic serranines, suggesting that this form of sex allocation may be more limited by phylogenetic inertia. Overall, this work strongly supports sexual lability within teleost fishes and confirms evolutionary theories of sex allocation in this group of vertebrates.

Population-level mating patterns and fluctuating asymmetry in swordtail hybrids

NASA Astrophysics Data System (ADS)

Culumber, Zachary W.; Rosenthal, Gil G.

2013-08-01

Morphological symmetry is a correlate of fitness-related traits or even a direct target of mate choice in a variety of taxa. In these taxa, when females discriminate among potential mates, increased selection on males should reduce fluctuating asymmetry (FA). Hybrid populations of the swordtails Xiphophorus birchmanni and Xiphophorus malinche vary from panmictic (unstructured) to highly structured, in which reproductive isolation is maintained among hybrids and parental species. We predicted that FA in flanking vertical bars used in sexual signalling should be lower in structured populations, where non-random mating patterns are observed. FA in vertical bars was markedly lower in structured populations than in parental and unstructured hybrid populations. There was no difference in FA between parentals and hybrids, suggesting that hybridisation does not directly affect FA. Rather, variation in FA likely results from contrasting mating patterns in unstructured and structured populations.

Genetic effects on mating success and partner choice in a social mammal

PubMed Central

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

Preferential Mating in Symmetric Multilocus Systems: Limits for Multiallelism and for Many Loci

PubMed Central

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

Mating system and early viability resistance to habitat fragmentation in a bird-pollinated eucalypt

PubMed Central

Breed, M F; Ottewell, K M; Gardner, M G; Marklund, M H K; Stead, M G; Harris, J B C; Lowe, A J

2015-01-01

Habitat fragmentation has been shown to disrupt ecosystem processes such as plant-pollinator mutualisms. Consequently, mating patterns in remnant tree populations are expected to shift towards increased inbreeding and reduced pollen diversity, with fitness consequences for future generations. However, mating patterns and phenotypic assessments of open-pollinated progeny have rarely been combined in a single study. Here, we collected seeds from 37 Eucalyptus incrassata trees from contrasting stand densities following recent clearance in a single South Australian population (intact woodland=12.6 trees ha−1; isolated pasture=1.7 trees ha−1; population area=10 km2). 649 progeny from these trees were genotyped at eight microsatellite loci. We estimated genetic diversity, spatial genetic structure, indirect contemporary pollen flow and mating patterns for adults older than the clearance events and open-pollinated progeny sired post-clearance. A proxy of early stage progeny viability was assessed in a common garden experiment. Density had no impact on mating patterns, adult and progeny genetic diversity or progeny growth, but was associated with increased mean pollen dispersal. Weak spatial genetic structure among adults suggests high historical gene flow. We observed preliminary evidence for inbreeding depression related to stress caused by fungal infection, but which was not associated with density. Higher observed heterozygosities in adults compared with progeny may relate to weak selection on progeny and lifetime-accumulated mortality of inbred adults. E. incrassata appears to be resistant to the negative mating pattern and fitness changes expected within fragmented landscapes. This pattern is likely explained by strong outcrossing and regular long-distance pollen flow. PMID:23188172

Drosophila Cuticular Hydrocarbons Revisited: Mating Status Alters Cuticular Profiles

PubMed Central

Cobb, Matthew; Ferveur, Jean-François

2010-01-01

Most living organisms use pheromones for inter-individual communication. In Drosophila melanogaster flies, several pheromones perceived either by contact/at a short distance (cuticular hydrocarbons, CHs), or at a longer distance (cis-vaccenyl acetate, cVA), affect courtship and mating behaviours. However, it has not previously been possible to precisely identify all potential pheromonal compounds and simultaneously monitor their variation on a time scale. To overcome this limitation, we combined Solid Phase Micro-Extraction with gas-chromatography coupled with mass-spectrometry. This allowed us (i) to identify 59 cuticular compounds, including 17 new CHs; (ii) to precisely quantify the amount of each compound that could be detected by another fly, and (iii) to measure the variation of these substances as a function of aging and mating. Sex-specific variation appeared with age, while mating affected cuticular compounds in both sexes with three possible patterns: variation was (i) reciprocal in the two sexes, suggesting a passive mechanical transfer during mating, (ii) parallel in both sexes, such as for cVA which strikingly appeared during mating, or (iii) unilateral, presumably as a result of sexual interaction. We provide a complete reassessment of all Drosophila CHs and suggest that the chemical conversation between male and female flies is far more complex than is generally accepted. We conclude that focusing on individual compounds will not provide a satisfactory understanding of the evolution and function of chemical communication in Drosophila. PMID:20231905

How multiple mating by females affects sexual selection

PubMed Central

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

Size-assortative mating and sexual size dimorphism are predictable from simple mechanics of mate-grasping behavior

PubMed Central

2010-01-01

Background A major challenge in evolutionary biology is to understand the typically complex interactions between diverse counter-balancing factors of Darwinian selection for size assortative mating and sexual size dimorphism. It appears that rarely a simple mechanism could provide a major explanation of these phenomena. Mechanics of behaviors can predict animal morphology, such like adaptations to locomotion in animals from various of taxa, but its potential to predict size-assortative mating and its evolutionary consequences has been less explored. Mate-grasping by males, using specialized adaptive morphologies of their forelegs, midlegs or even antennae wrapped around female body at specific locations, is a general mating strategy of many animals, but the contribution of the mechanics of this wide-spread behavior to the evolution of mating behavior and sexual size dimorphism has been largely ignored. Results Here, we explore the consequences of a simple, and previously ignored, fact that in a grasping posture the position of the male's grasping appendages relative to the female's body is often a function of body size difference between the sexes. Using an approach taken from robot mechanics we model coercive grasping of females by water strider Gerris gracilicornis males during mating initiation struggles. We determine that the male optimal size (relative to the female size), which gives the males the highest grasping force, properly predicts the experimentally measured highest mating success. Through field sampling and simulation modeling of a natural population we determine that the simple mechanical model, which ignores most of the other hypothetical counter-balancing selection pressures on body size, is sufficient to account for size-assortative mating pattern as well as species-specific sexual dimorphism in body size of G. gracilicornis. Conclusion The results indicate how a simple and previously overlooked physical mechanism common in many taxa is sufficient to account for, or importantly contribute to, size-assortative mating and its consequences for the evolution of sexual size dimorphism. PMID:21092131

46 CFR 11.463 - General requirements for national endorsements as master, mate (pilot), and apprentice mate...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 1 2014-10-01 2014-10-01 false General requirements for national endorsements as master... national endorsements as master, mate (pilot), and apprentice mate (steersman) of towing vessels. (a) The Coast Guard issues the following endorsements for towing vessels: (1) Master of towing vessels. (2...

Social pairing of Seychelles warblers under reduced constraints: MHC, neutral heterozygosity, and age.

PubMed

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.

Restricted mating dispersal and strong breeding group structure in a mid-sized marsupial mammal (Petrogale penicillata).

PubMed

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.

Feederism: an exaggeration of a normative mate selection preference?

PubMed

Terry, Lesley L; Suschinsky, Kelly D; Lalumière, Martin L; Vasey, Paul L

2012-02-01

Quinsey and Lalumière (1995) suggested that some, if not most, paraphilias are exaggerated manifestations of more normative and functional mate selection preferences. The present study tested whether Feederism, a fat fetish focused on erotic eating, feeding, and gaining weight, is an exaggeration of a sexual arousal pattern commonly seen in the general population. Thirty participants (15 men and 15 women) recruited from the general population were assessed using penile plethysmography and vaginal photoplethysmography, respectively. None of the participants were self-identified Feeders or Feedees. Participants were shown sexual, neutral, and feeding still images while listening to audio recordings of sexual, neutral, and feeding stories. Participants did not genitally respond to feeding stimuli. However, both men and women subjectively rated feeding stimuli as more sexually arousing than neutral stimuli. We discuss the discordance between physiological and self-reported sexual arousal in the context of sex differences in sexual concordance and implications for future research.

How universal are human mate choices? Size does not matter when Hadza foragers are choosing a mate

PubMed Central

Sear, Rebecca; Marlowe, Frank W.

2009-01-01

It has been argued that size matters on the human mate market: both stated preferences and mate choices have been found to be non-random with respect to height and weight. But how universal are these patterns? Most of the literature on human mating patterns is based on post-industrial societies. Much less is known about mating behaviour in more traditional societies. Here we investigate mate choice by analysing whether there is any evidence for non-random mating with respect to size and strength in a forager community, the Hadza of Tanzania. We test whether couples assort for height, weight, body mass index (BMI), per cent fat and grip strength. We test whether there is a male-taller norm. Finally, we test for an association between anthropometric variables and number of marriages. Our results show no evidence for assortative mating for height, weight, BMI or per cent fat; no evidence for a male-taller norm and no evidence that number of marriages is associated with our size variables. Hadza couples may assort positively for grip strength, but grip strength does not affect the number of marriages. Overall we conclude that, in contrast to post-industrial societies, mating appears to be random with respect to size in the Hadza. PMID:19570778

Seminal fluid protein depletion and replenishment in the fruit fly, Drosophila melanogaster: an ELISA-based method for tracking individual ejaculates

PubMed Central

Sirot, Laura K.; Wolfner, Mariana F.

2014-01-01

In many species, seminal fluid proteins (SFPs) affect female post-mating behavioral patterns, including sperm storage, egg laying, feeding, and remating. Yet, few studies have investigated the patterns of allocation, depletion, and replenishment of SFPs in male animals, despite the importance of these proteins to male and female reproductive success. To investigate such SFP dynamics, it is necessary to have a sensitive method for quantifying SFP levels in males and mated females. We developed such a method by adapting the enzyme-linked immunosorbent assay (ELISA) using anti-SFP antibodies. Here, we first use two Drosophila melanogaster SFPs (ovulin and sex peptide) to demonstrate that ELISAs provide accurate measures of SFP levels. We find that, consistent with previous data from Western blotting or immunofluorescence studies, levels of both ovulin and sex peptide decline in the mated female with time since mating, but they do so at different rates. We then use ELISAs to show that males become depleted of SFPs with repeated matings, but that previously mated males are able to transfer “virgin” levels of SFPs after 3 days of sexual inactivity. Finally, we demonstrate that ELISAs can detect SFPs from wild-caught D. melanogaster males and, thus, potentially can be used to track mating patterns in the wild. This method of measuring SFP dynamics can be used in a wide range of species to address questions related to male reproductive investment, female mating history, and variation in female post-mating behavioral changes. PMID:24733957

Disruptive ecological selection on a mating cue.

PubMed

Merrill, Richard M; Wallbank, Richard W R; Bull, Vanessa; Salazar, Patricio C A; Mallet, James; Stevens, Martin; Jiggins, Chris D

2012-12-22

Adaptation to divergent ecological niches can result in speciation. Traits subject to disruptive selection that also contribute to non-random mating will facilitate speciation with gene flow. Such 'magic' or 'multiple-effect' traits may be widespread and important for generating biodiversity, but strong empirical evidence is still lacking. Although there is evidence that putative ecological traits are indeed involved in assortative mating, evidence that these same traits are under divergent selection is considerably weaker. Heliconius butterfly wing patterns are subject to positive frequency-dependent selection by predators, owing to aposematism and Müllerian mimicry, and divergent colour patterns are used by closely related species to recognize potential mates. The amenability of colour patterns to experimental manipulation, independent of other traits, presents an excellent opportunity to test their role during speciation. We conducted field experiments with artificial butterflies, designed to match natural butterflies with respect to avian vision. These were complemented with enclosure trials with live birds and real butterflies. Our experiments showed that hybrid colour-pattern phenotypes are attacked more frequently than parental forms. For the first time, we demonstrate disruptive ecological selection on a trait that also acts as a mating cue.

Integration of Spectral Reflectance across the Plumage: Implications for Mating Patterns

PubMed Central

Laczi, Miklós; Török, János; Rosivall, Balázs; Hegyi, Gergely

2011-01-01

Background In complex sexual signaling systems such as plumage color, developmental or genetic links may occur among seemingly distinct traits. However, the interrelations of such traits and the functional significance of their integration rarely have been examined. Methodology/Principal Findings We investigated the parallel variation of two reflectance descriptors (brightness and UV chroma) across depigmented and melanized plumage areas of collared flycatchers (Ficedula albicollis), and the possible role of integrated color signals in mate acquisition. We found moderate integration in brightness and UV chroma across the plumage, with similar correlation structures in the two sexes despite the strong sexual dichromatism. Patterns of parallel color change across the plumage were largely unrelated to ornamental white patch sizes, but they all showed strong assortative mating between the sexes. Comparing different types of assortative mating patterns for individual spectral variables suggested a distinct role for plumage-level color axes in mate acquisition. Conclusions/Significance Our results indicate that the plumage-level, parallel variation of coloration might play a role in mate acquisition. This study underlines the importance of considering potential developmental and functional integration among apparently different ornaments in studies of sexual selection. PMID:21853088

Understanding Patterns of Evolution Acceptance--A New Implementation of the Measure of Acceptance of the Theory of Evolution (MATE) with Midwestern University Students

ERIC Educational Resources Information Center

Romine, William L.; Walter, Emily M.; Bosse, Ephiram; Todd, Amber N.

2017-01-01

We validate the Measure of Acceptance of the Theory of Evolution (MATE) on undergraduate students using the Rasch model and utilize the MATE to explore qualitatively how students express their acceptance of evolution. At least 24 studies have used the MATE, most with the assumption that it is unidimensional. However, we found that the MATE is best…

Behavior and Body Patterns of the Larger Pacific Striped Octopus.

PubMed

Caldwell, Roy L; Ross, Richard; Rodaniche, Arcadio; Huffard, Christine L

2015-01-01

Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

Behavior and Body Patterns of the Larger Pacific Striped Octopus

PubMed Central

Caldwell, Roy L.; Ross, Richard; Rodaniche, Arcadio; Huffard, Christine L.

2015-01-01

Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012–2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown. PMID:26266543

Social pairing of Seychelles warblers under reduced constraints: MHC, neutral heterozygosity, and age

PubMed Central

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

The unexpected but understandable dynamics of mating, paternity and paternal care in the ocellated wrasse

PubMed Central

Alonzo, Suzanne H.; Heckman, Kellie L.

2010-01-01

Although theory generally predicts that males should reduce paternal care in response to cues that predict increased sperm competition and decreased paternity, empirical patterns are equivocal. Some studies have found the predicted decrease in male care with increased sperm competition, while even more studies report no effect of paternity or sperm competition on male care. Here, we report the first example, to our knowledge, of paternal care increasing with the risk and intensity of sperm competition, in the ocellated wrasse (Symphodus ocellatus). Theory also predicts that if paternal care varies and is important to female fitness, female choice among males and male indicators traits of expected paternal care should evolve. Despite a non-random distribution of mating success among nests, we found no evidence for female choice among parental males. Finally, we document the highest published levels of extra-pair paternity for a species with exclusive and obligate male care: genetic paternity analyses revealed cuckoldry at 100 per cent of nests and 28 per cent of all offspring were not sired by the male caring for them. While not predicted by any existing theory, these unexpected reproductive patterns become understandable if we consider how male and female mating and parental care interact simultaneously in this and probably many other species. PMID:19812085

IMPLICATIONS OF MATING PATTERNS FOR CONSERVATION OF THE ENDANGERED PLANT ERIOGONUM OVALIFOLIUM VAR. VINEUM (POLYGONACEAE). (R826102)

EPA Science Inventory

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...

Chronic Social Isolation Enhances Reproduction in the Monogamous Prairie Vole (Microtus ochrogaster)

PubMed Central

Perry, Adam N.; Carter, C. Sue; Cushing, Bruce S.

2016-01-01

Chronic stressors are generally considered to disrupt reproduction and inhibit mating. Here we test the hypothesis that a chronic stressor, specifically social isolation, can facilitate adaptive changes that enhance/accelerate reproductive effort. In general, monogamous species display high levels of prosociality, delayed sexual maturation, and greater parental investment in fewer, higher quality offspring compared with closely related polygynous species. We predicted that chronic social isolation would promote behavioral and neurochemical patterns in prairie voles associated with polygyny. Male and female prairie voles were isolated for four weeks and changes in mating behavior, alloparental care, estrogen receptor (ER) α expression and tyrosine hydroxylase (TH) expression in brain regions regulating sociosexual behavior were examined. In males, isolation accelerated copulation, increased ERα in the medial amygdala (MEApd) and bed nucleus of the stria terminalis (BSTpm), and reduced TH expression in the MEApd and BSTpm, but had no effect on alloparental behavior. In females, isolation resulted in more rapid estrus induction and reduced TH expression in the MEApd and BSTpm, but had no effect on estradiol sensitivity or ERα expression. The results support the hypothesis that ERα expression in the MEApd and BSTpm is a critical determinant of male copulatory behavior and/or mating system. The lack of change in alloparental behavior suggests that changes in prosocial behavior are selective and regulated by different mechanisms. The results also suggest that TH in the MEApd and BSTpm may play a critical role in determining mating behavior in both sexes. PMID:26939085

Heart rate patterns during courtship and mating in rams and in estrous and nonestrous ewes ().

PubMed

Orihuela, A; Omaña, J C; Ungerfeld, R

2016-02-01

The aim of this study was to compare the heart rate (HR) patterns in rams mated with estrous or nonestrous ewes and in mated estrous and nonestrous ewes () during courtship and mating. For this purpose, HR and behavior were recorded using a radio telemetry recording system and a closed-circuit television system with video recording, respectively. Rams were joined with either an estrous ( = 10) or a nonestrous ( = 10) ewe that was restrained in a stanchion by the neck. Data were continuously recorded until each ram performed 3 ejaculations. Eight days later, the HR of the 10 estrous and 10 nonestrous ewes was recorded during mating. Although the time between entrance into the yard and the first ejaculation was similar across rams, rams that mounted estrous ewes were faster at attaining their second (3min5s ± 17 s vs. 5min28s ± 18 s) and third (7min58s ± 45 s vs. 12 min ± 1min14s) ejaculations (all < 0.05). By contrast, no differences in HR were observed between rams that interacted with estrous versus nonestrous ewes. In all cases, HR reached maximum values immediately after each ejaculation and the HR pattern was similar across ejaculations (first, second, and third). Although HR was similar between estrous and nonestrous ewes before mating, nonestrous ewes had higher HR ( < 0.05) during mating. In summary, 1) rams that mated estrous ewes displayed shorter interejaculation periods but HR did not differ between groups of rams during any ejaculation (first, second, or third), 2) HR for both groups of rams peaked shortly after each ejaculation, and 3) HR increased more in nonestrous than in estrous ewes while mating.

Choosy Wolves? Heterozygote Advantage But No Evidence of MHC-Based Disassortative Mating.

PubMed

Galaverni, Marco; Caniglia, Romolo; Milanesi, Pietro; Lapalombella, Silvana; Fabbri, Elena; Randi, Ettore

2016-03-01

A variety of nonrandom mate choice strategies, including disassortative mating, are used by vertebrate species to avoid inbreeding, maintain heterozygosity and increase fitness. Disassortative mating may be mediated by the major histocompatibility complex (MHC), an important gene cluster controlling immune responses to pathogens. We investigated the patterns of mate choice in 26 wild-living breeding pairs of gray wolf (Canis lupus) that were identified through noninvasive genetic methods and genotyped at 3 MHC class II and 12 autosomal microsatellite (STR) loci. We tested for deviations from random mating and evaluated the covariance of genetic variables at functional and STR markers with fitness proxies deduced from pedigree reconstructions. Results did not show evidences of MHC-based disassortative mating. Rather we found a higher peptide similarity between mates at MHC loci as compared with random expectations. Fitness values were positively correlated with heterozygosity of the breeders at both MHC and STR loci, whereas they decreased with relatedness at STRs. These findings may indicate fitness advantages for breeders that, while avoiding highly related mates, are more similar at the MHC and have high levels of heterozygosity overall. Such a pattern of MHC-assortative mating may reflect local coadaptation of the breeders, while a reduction in genetic diversity may be balanced by heterozygote advantages. © The American Genetic Association 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Oxytocin receptor density is associated with male mating tactics and social monogamy

PubMed Central

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

Measuring genomic pre-selection in theory and in practice

USDA-ARS?s Scientific Manuscript database

Potential biases from genomic pre-selection were estimated from actual selection and mating patterns of US Holsteins. Traditional models using only phenotypes and pedigrees do not adjust for average genomic merit of an animal’s parents, progeny, mates, or contemporaries. Positive assortative mating ...

Re-mating across years and intralineage polygyny are associated with greater than expected levels of inbreeding in wild red deer

PubMed Central

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

Oxytocin receptor density is associated with male mating tactics and social monogamy.

PubMed

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.

Airborne-pollen pool and mating pattern in a hybrid zone between Pinus pumila and P. parviflora var. pentaphylla.

PubMed

Ito, Megumi; Suyama, Yoshihisa; Ohsawa, Takeshi A; Watano, Yasuyuki

2008-12-01

The reproductive isolation barriers and the mating patterns among Pinus pumila, P. parviflora var. pentaphylla and their hybrids were examined by flowering phenology and genetic assays of three life stages: airborne-pollen grains, adults and seeds, in a hybrid zone on Mount Apoi, Hokkaido, Japan. Chloroplast DNA composition of the airborne-pollen was determined by single-pollen polymerase chain reaction. Mating patterns were analysed by estimating the molecular hybrid index of the seed parent, their seed embryos and pollen parents. The observation of flowering phenology showed that the flowering of P. pumila precedes that of P. parviflora var. pentaphylla by about 6 to 10 days within the same altitudinal ranges. Although this prezygotic isolation barrier is effective, the genetic assay of airborne-pollen showed that the two pine species, particularly P. pumila, still have chances to form F(1) hybrid seeds. Both parental species showed a strong assortative mating pattern; F(1) seeds were found in only 1.4% of seeds from P. pumila mother trees and not at all in P. parviflora var. pentaphylla. The assortative mating was concluded as the combined result of flowering time differentiation and cross-incompatibility. In contrast to the parental species, hybrids were fertilized evenly by the two parental species and themselves. The breakdown of prezygotic barriers (intermediate flowering phenology) and cross-incompatibility may account for the unselective mating. It is suggested that introgression is ongoing on Mount Apoi through backcrossing between hybrids and parental species, despite strong isolation barriers between the parental species.

Evolution of the mating system in colonizing plants.

PubMed

Pannell, John R

2015-05-01

Colonization is likely to be more successful for species with an ability to self-fertilize and thus to establish new populations as single individuals. As a result, self-compatibility should be common among colonizing species. This idea, labelled 'Baker's law', has been influential in discussions of sexual-system and mating-system evolution. However, its generality has been questioned, because models of the evolution of dispersal and the mating system predict an association between high dispersal rates and outcrossing rather than selfing, and because of many apparent counter examples to the law. The contrasting predictions made by models invoking Baker's law versus those for the evolution of the mating system and dispersal urges a reassessment of how we should view both these traits. Here, I review the literature on the evolution of mating and dispersal in colonizing species, with a focus on conceptual issues. I argue for the importance of distinguishing between the selfing or outcrossing rate and a simple ability to self-fertilize, as well as for the need for a more nuanced consideration of dispersal. Colonizing species will be characterized by different phases in their life pattern: dispersal to new habitat, implying an ecological sieve on dispersal traits; establishment and a phase of growth following colonization, implying a sieve on reproductive traits; and a phase of demographic stasis at high density, during which new trait associations can evolve through local adaptation. This dynamic means that the sorting of mating-system and dispersal traits should change over time, making simple predictions difficult. © 2015 John Wiley & Sons Ltd.

Global biogeography of mating system variation in seed plants.

PubMed

Moeller, David A; Briscoe Runquist, Ryan D; Moe, Annika M; Geber, Monica A; Goodwillie, Carol; Cheptou, Pierre-Olivier; Eckert, Christopher G; Elle, Elizabeth; Johnston, Mark O; Kalisz, Susan; Ree, Richard H; Sargent, Risa D; Vallejo-Marin, Mario; Winn, Alice A

2017-03-01

Latitudinal gradients in biotic interactions have been suggested as causes of global patterns of biodiversity and phenotypic variation. Plant biologists have long speculated that outcrossing mating systems are more common at low than high latitudes owing to a greater predictability of plant-pollinator interactions in the tropics; however, these ideas have not previously been tested. Here, we present the first global biogeographic analysis of plant mating systems based on 624 published studies from 492 taxa. We found a weak decline in outcrossing rate towards higher latitudes and among some biomes, but no biogeographic patterns in the frequency of self-incompatibility. Incorporating life history and growth form into biogeographic analyses reduced or eliminated the importance of latitude and biome in predicting outcrossing or self-incompatibility. Our results suggest that biogeographic patterns in mating system are more likely a reflection of the frequency of life forms across latitudes rather than the strength of plant-pollinator interactions. © 2017 John Wiley & Sons Ltd/CNRS.

Chronic social isolation enhances reproduction in the monogamous prairie vole (Microtus ochrogaster).

PubMed

Perry, Adam N; Carter, C Sue; Cushing, Bruce S

2016-06-01

Chronic stressors are generally considered to disrupt reproduction and inhibit mating. Here we test the hypothesis that a chronic stressor, specifically social isolation, can facilitate adaptive changes that enhance/accelerate reproductive effort. In general, monogamous species display high levels of prosociality, delayed sexual maturation, and greater parental investment in fewer, higher quality offspring compared with closely related polygynous species. We predicted that chronic social isolation would promote behavioral and neurochemical patterns in prairie voles associated with polygyny. Male and female prairie voles were isolated for four weeks and changes in mating behavior, alloparental care, estrogen receptor (ER) α expression and tyrosine hydroxylase (TH) expression in brain regions regulating sociosexual behavior were examined. In males, isolation accelerated copulation, increased ERα in the medial amygdala (MEApd) and bed nucleus of the stria terminalis (BSTpm), and reduced TH expression in the MEApd and BSTpm, but had no effect on alloparental behavior. In females, isolation resulted in more rapid estrus induction and reduced TH expression in the MEApd and BSTpm, but had no effect on estradiol sensitivity or ERα expression. The results support the hypothesis that ERα expression in the MEApd and BSTpm is a critical determinant of male copulatory behavior and/or mating system. The lack of change in alloparental behavior suggests that changes in prosocial behavior are selective and regulated by different mechanisms. The results also suggest that TH in the MEApd and BSTpm may play a critical role in determining mating behavior in both sexes. Copyright © 2016 Elsevier Ltd. All rights reserved.

SEXUAL BEHAVIOR IN MALE RODENTS

PubMed Central

Hull, Elaine M.; Dominguez, Juan M.

2007-01-01

The hormonal factors and neural circuitry that control copulation are similar across rodent species, although there are differences in specific behavior patterns. Both estradiol (E) and dihydrotestosterone (DHT) contribute to the activation of mating, although E is more important for copulation and DHT, for genital reflexes. Hormonal activation of the medial preoptic area (MPOA) is most effective, although implants in the medial amygdala (MeA) can also stimulate mounting in castrates. Chemosensory inputs from the main and accessory olfactory systems are the most important stimuli for mating in rodents, especially in hamsters, although genitosensory input also contributes. Dopamine agonists facilitate sexual behavior, and serotonin (5-HT) is generally inhibitory, though certain 5-HT receptor subtypes facilitate erection or ejaculation. Norepinephrine agonists and opiates have dose-dependent effects, with low doses facilitating and high doses inhibiting behavior. PMID:17499249

Alternative Mating Tactics in Male Chameleons (Chamaeleo chamaeleon) Are Evident in Both Long-Term Body Color and Short-Term Courtship Pattern

PubMed Central

Keren-Rotem, Tammy; Levy, Noga; Wolf, Lior; Bouskila, Amos; Geffen, Eli

2016-01-01

Alternative mating tactics in males of various taxa are associated with body color, body size, and social status. Chameleons are known for their ability to change body color following immediate environmental or social stimuli. In this study, we examined whether the differential appearance of male common chameleon during the breeding season is indeed an expression of alternative mating tactics. We documented body color of males and used computer vision techniques to classify images of individuals into discrete color patterns associated with seasons, individual characteristics, and social contexts. Our findings revealed no differences in body color and color patterns among males during the non-breeding season. However, during the breeding season males appeared in several color displays, which reflected body size, social status, and behavioral patterns. Furthermore, smaller and younger males resembled the appearance of small females. Consequently, we suggest that long-term color change in males during the breeding season reflects male alternative mating tactics. Upon encounter with a receptive female, males rapidly alter their appearance to that of a specific brief courtship display, which reflects their social status. The females, however, copulated indiscriminately in respect to male color patterns. Thus, we suggest that the differential color patterns displayed by males during the breeding season are largely aimed at inter-male signaling. PMID:27409771

Reproductive investment when mate quality varies: differential allocation versus reproductive compensation.

PubMed

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.

Social organization of sea otters in Prince William Sound, Alaska

USGS Publications Warehouse

Garshelis, David L.; Johnson, Ancel M.; Garshelis, Judith A.

1984-01-01

Sea otters in Prince William Sound. Alaska, were spatially segregated into predominantly (97%) male areas at the front of the expanding population and breeding areas with fewer (up to 33%) males. From 1975 to 1984 we captured and marked 267 otters with tags and (or) radio transmitters and investigated their reproductive strategies, social relationships, and patterns of sexual segregation. Mating occurred year-round, but peaked in September and October. Females first bred at 4 years of age and were capable of pupping annually; they generally separated from their pup before mating. Males established breeding territories that enabled prolonged precopulatory interactions that may have prompted female–pup separation and post-copulatory interactions that precluded females from mating with other males. Male mating success was related to age, weight, territory quality, and the length of time they maintained their territory. After the breeding season, territorial males returned to male areas where food was more abundant. Young, dispersing males also entered male areas and remained there until attaining breeding age. In male areas, otters commonly rested in groups of >50 individuals. Gregariousness promoted social interactions and likely enhanced food finding and (historically) predator protection. As food diminished, males moved into adjacent, unoccupied regions; females then occupied former male areas.

Sex roles and mutual mate choice matter during mate sampling.

PubMed

Myhre, Lise Cats; de Jong, Karen; Forsgren, Elisabet; Amundsen, Trond

2012-06-01

The roles of females and males in mating competition and mate choice have lately proven more variable, between and within species, than previously thought. In nature, mating competition occurs during mate search and is expected to be regulated by the numbers of potential mates and same-sex competitors. Here, we present the first study to test how a temporal change in sex roles affects mating competition and mate choice during mate sampling. Our model system (the marine fish Gobiusculus flavescens) is uniquely suitable because of its change in sex roles, from conventional to reversed, over the breeding season. As predicted from sex role theory, courtship was typically initiated by males and terminated by females early in the breeding season. The opposite pattern was observed late in the season, at which time several females often simultaneously courted the same male. Mate-searching females visited more males early than late in the breeding season. Our study shows that mutual mate choice and mating competition can have profound effects on female and male behavior. Future work needs to consider the dynamic nature of mating competition and mate choice if we aim to fully understand sexual selection in the wild.

Natal dispersal patterns are not associated with inbreeding avoidance in the Seychelles warbler.

PubMed

Eikenaar, C; Komdeur, J; Richardson, D S

2008-07-01

In this study, we test whether patterns of territory inheritance, social mate choice and female-biased natal dispersal act as inbreeding avoidance mechanisms in the cooperatively breeding Seychelles warbler. Our results show that Seychelles warblers do not reduce the likelihood of inbreeding by avoiding related individuals as mates. The occurrence of natural and experimentally induced territory inheritance did not depend on whether the remaining breeder was a parent of the potential inheritor or an unrelated breeder. Furthermore, dispersing individuals were no less related to their eventual mates than expected given the pool of candidates they could mate with. The female bias in natal dispersal distance observed in the Seychelles warbler does not facilitate inbreeding avoidance because, contrary to our prediction, there was no sex difference in the clustering of related opposite sex breeders around the natal territories of dispersers. As a result, the chance of females mating with relatives was not reduced by their greater dispersal distance compared with that of males.

Mating and Parental Care in Lake Tanganyika's Cichlids

PubMed Central

Sefc, Kristina M.

2011-01-01

Cichlid fishes of Lake Tanganyika display a variety of mating and parental care behaviors, including polygamous and monogamous mouthbrooding and substrate breeding, cooperative breeding, as well as various alternative reproductive tactics such as sneaking and piracy. Moreover, reproductive behaviors sometimes vary within species both in space and in time. Here, I survey reports on mating and parenting behaviors of Lake Tanganyika cichlid species and address the evolution of mating and parental care patterns and sexual dimorphism. Notes on measures of sexual selection intensity and the difficulties of defining mating systems and estimating selection intensities at species level conclude the essay. PMID:21822482

The genomic signature of sexual selection in the genetic diversity of the sex chromosomes and autosomes.

PubMed

Corl, Ammon; Ellegren, Hans

2012-07-01

Genomic levels of variation can help reveal the selective and demographic forces that have affected a species during its history. The relative amount of genetic diversity observed on the sex chromosomes as compared to the autosomes is predicted to differ among monogamous and polygynous species. Many species show departures from the expectation for monogamy, but it can be difficult to conclude that this pattern results from variation in mating system because forces other than sexual selection can act upon sex chromosome genetic diversity. As a critical test of the role of mating system, we compared levels of genetic diversity on the Z chromosome and autosomes of phylogenetically independent pairs of shorebirds that differed in their mating systems. We found general support for sexual selection shaping sex chromosome diversity because most polygynous species showed relatively reduced genetic variation on their Z chromosomes as compared to monogamous species. Differences in levels of genetic diversity between the sex chromosomes and autosomes may therefore contribute to understanding the long-term history of sexual selection experienced by a species. © 2012 The Author(s).

Reinforcement and a cline in mating behaviour evolve in response to secondary contact and hybridization in shield-back katydids (Orthoptera: Tettigoniidae).

PubMed

Cole, J A

2016-09-01

In a dispersal-limited species that has evolved reproductive character displacement at a contact zone, a cline in mating behaviour may result if gene flow diffuses alleles out of the contact zone into allopatric populations. Prior work has found such a clinal pattern in the shield-back katydid Aglaothorax morsei, in which the male calling songs in a sympatric population have a displaced, short interpulse interval that increases in length with increasing distance from the contact zone. In this study, molecular phylogenetic and female preference data show that (1) sympatric populations result from secondary contact, (2) hybridization in sympatry has resulted in unidirectional mitochondrial introgression and (3) female preferences are consistent with reproductive character displacement and could generate a cline in mating behaviour. These data together suggest a history of reinforcement, generally considered rare in acoustically communicating insects; thus, Aglaothorax represents an important example of a rarely documented evolutionary process. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Evolutionary Trade-Off between Secondary Sexual Traits and Ejaculates.

PubMed

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.

Mate choice for major histocompatibility complex genetic divergence as a bet-hedging strategy in the Atlantic salmon (Salmo salar).

PubMed

Evans, Melissa L; Dionne, Mélanie; Miller, Kristina M; Bernatchez, Louis

2012-01-22

Major histocompatibility complex (MHC)-dependent mating preferences have been observed across vertebrate taxa and these preferences are expected to promote offspring disease resistance and ultimately, viability. However, little empirical evidence linking MHC-dependent mate choice and fitness is available, particularly in wild populations. Here, we explore the adaptive potential of previously observed patterns of MHC-dependent mate choice in a wild population of Atlantic salmon (Salmo salar) in Québec, Canada, by examining the relationship between MHC genetic variation and adult reproductive success and offspring survival over 3 years of study. While Atlantic salmon choose their mates in order to increase MHC diversity in offspring, adult reproductive success was in fact maximized between pairs exhibiting an intermediate level of MHC dissimilarity. Moreover, patterns of offspring survival between years 0+ and 1+, and 1+ and 2+ and population genetic structure at the MHC locus relative to microsatellite loci indicate that strong temporal variation in selection is likely to be operating on the MHC. We interpret MHC-dependent mate choice for diversity as a likely bet-hedging strategy that maximizes parental fitness in the face of temporally variable and unpredictable natural selection pressures.

Mate choice for major histocompatibility complex genetic divergence as a bet-hedging strategy in the Atlantic salmon (Salmo salar)

PubMed Central

Evans, Melissa L.; Dionne, Mélanie; Miller, Kristina M.; Bernatchez, Louis

2012-01-01

Major histocompatibility complex (MHC)-dependent mating preferences have been observed across vertebrate taxa and these preferences are expected to promote offspring disease resistance and ultimately, viability. However, little empirical evidence linking MHC-dependent mate choice and fitness is available, particularly in wild populations. Here, we explore the adaptive potential of previously observed patterns of MHC-dependent mate choice in a wild population of Atlantic salmon (Salmo salar) in Québec, Canada, by examining the relationship between MHC genetic variation and adult reproductive success and offspring survival over 3 years of study. While Atlantic salmon choose their mates in order to increase MHC diversity in offspring, adult reproductive success was in fact maximized between pairs exhibiting an intermediate level of MHC dissimilarity. Moreover, patterns of offspring survival between years 0+ and 1+, and 1+ and 2+ and population genetic structure at the MHC locus relative to microsatellite loci indicate that strong temporal variation in selection is likely to be operating on the MHC. We interpret MHC-dependent mate choice for diversity as a likely bet-hedging strategy that maximizes parental fitness in the face of temporally variable and unpredictable natural selection pressures. PMID:21697172

Effects of Cyclic Feeding and Starvation, Mating, and Sperm Condition on Egg Production and Fertility in the Common Bed Bug (Hemiptera: Cimicidae).

PubMed

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.

Hybrid female mate choice as a species isolating mechanism: environment matters.

PubMed

Schmidt, E M; Pfennig, K S

2016-04-01

A fundamental goal of biology is to understand how new species arise and are maintained. Female mate choice is potentially critical to the speciation process: mate choice can prevent hybridization and thereby generate reproductive isolation between potentially interbreeding groups. Yet, in systems where hybridization occurs, mate choice by hybrid females might also play a key role in reproductive isolation by affecting hybrid fitness and contributing to patterns of gene flow between species. We evaluated whether hybrid mate choice behaviour could serve as such an isolating mechanism using spadefoot toad hybrids of Spea multiplicata and Spea bombifrons. We assessed the mate preferences of female hybrid spadefoot toads for sterile hybrid males vs. pure-species males in two alternative habitat types in which spadefoots breed: deep or shallow water. We found that, in deep water, hybrid females preferred the calls of sterile hybrid males to those of S. multiplicata males. Thus, maladaptive hybrid mate preferences could serve as an isolating mechanism. However, in shallow water, the preference for hybrid male calls was not expressed. Moreover, hybrid females did not prefer hybrid calls to those of S. bombifrons in either environment. Because hybrid female mate choice was context-dependent, its efficacy as a reproductive isolating mechanism will depend on both the environment in which females choose their mates as well as the relative frequencies of males in a given population. Thus, reproductive isolation between species, as well as habitat specific patterns of gene flow between species, might depend critically on the nature of hybrid mate preferences and the way in which they vary across environments. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Low reproductive skew despite high male-biased operational sex ratio in a glass frog with paternal care.

PubMed

Mangold, Alexandra; Trenkwalder, Katharina; Ringler, Max; Hödl, Walter; Ringler, Eva

2015-09-03

Reproductive skew, the uneven distribution of reproductive success among individuals, is a common feature of many animal populations. Several scenarios have been proposed to favour either high or low levels of reproductive skew. Particularly a male-biased operational sex ratio and the asynchronous arrival of females is expected to cause high variation in reproductive success among males. Recently it has been suggested that the type of benefits provided by males (fixed vs. dilutable) could also strongly impact individual mating patterns, and thereby affecting reproductive skew. We tested this hypothesis in Hyalinobatrachium valerioi, a Neotropical glass frog with prolonged breeding and paternal care. We monitored and genetically sampled a natural population in southwestern Costa Rica during the breeding season in 2012 and performed parentage analysis of adult frogs and tadpoles to investigate individual mating frequencies, possible mating preferences, and estimate reproductive skew in males and females. We identified a polygamous mating system, where high proportions of males (69 %) and females (94 %) reproduced successfully. The variance in male mating success could largely be attributed to differences in time spent calling at the reproductive site, but not to body size or relatedness. Female H. valerioi were not choosy and mated indiscriminately with available males. Our findings support the hypothesis that dilutable male benefits - such as parental care - can favour female polyandry and maintain low levels of reproductive skew among males within a population, even in the presence of direct male-male competition and a highly male-biased operational sex ratio. We hypothesize that low male reproductive skew might be a general characteristic in prolonged breeders with paternal care.

Context-dependent female mate choice maintains variation in male sexual activity

PubMed Central

Plath, Martin; Gismann, Jakob; Helfrich, Claudia; Bierbach, David

2017-01-01

The existence of individual variation in males' motivation to mate remains a conundrum as directional selection should favour high mating frequencies. Balancing selection resulting from (context-dependent) female mate choice could contribute to the maintenance of this behavioural polymorphism. In dichotomous choice tests, mosquitofish (Gambusia holbrooki) females preferred virtual males showing intermediate mating frequencies, reflecting females' tendencies to avoid harassment by highly sexually active males. When tested in the presence of a female shoal—which protects females from male harassment—focal females showed significantly stronger preferences for high sexual activity. A trade-off between (indirect) benefits and (direct) costs of mating with sexually active males probably explains context-dependent female mate choice, as costs depend on the social environment in which females choose their mates. No preference was observed when we tested virgin females, suggesting that the behavioural pattern described here is part of the learned behavioural repertoire of G. holbrooki females. PMID:28791157

Mate-choice copying in single and coupled women: the influence of mate acceptance and mate rejection decisions of other women.

PubMed

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.

Parenting across Racial and Class Lines: Assortative Mating Patterns of New Parents Who Are Married, Cohabiting, Dating or No Longer Romantically Involved

ERIC Educational Resources Information Center

Goldstein, Joshua R.; Harknett, Kristen

2006-01-01

We examine the assortative mating patterns of new parents who are married, cohabiting, romantically involved and no longer romantically involved. Using data from the Fragile Families and Child Wellbeing study, we find that relationship status at the time of a birth depends mainly on father's race rather than on whether mother and father's…

Variation in human mate choice: Simultaneously investigating heritability, parental influence, sexual imprinting, and assortative mating

PubMed Central

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

Variation in human mate choice: simultaneously investigating heritability, parental influence, sexual imprinting, and assortative mating.

PubMed

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.

Correlates of androgens in wild male Barbary macaques: Testing the challenge hypothesis.

PubMed

Rincon, Alan V; Maréchal, Laëtitia; Semple, Stuart; Majolo, Bonaventura; MacLarnon, Ann

2017-10-01

Investigating causes and consequences of variation in hormonal expression is a key focus in behavioral ecology. Many studies have explored patterns of secretion of the androgen testosterone in male vertebrates, using the challenge hypothesis (Wingfield, Hegner, Dufty, & Ball, 1990; The American Naturalist, 136(6), 829-846) as a theoretical framework. Rather than the classic association of testosterone with male sexual behavior, this hypothesis predicts that high levels of testosterone are associated with male-male reproductive competition but also inhibit paternal care. The hypothesis was originally developed for birds, and subsequently tested in other vertebrate taxa, including primates. Such studies have explored the link between testosterone and reproductive aggression as well as other measures of mating competition, or between testosterone and aspects of male behavior related to the presence of infants. Very few studies have simultaneously investigated the links between testosterone and male aggression, other aspects of mating competition and infant-related behavior. We tested predictions derived from the challenge hypothesis in wild male Barbary macaques (Macaca sylvanus), a species with marked breeding seasonality and high levels of male-infant affiliation, providing a powerful test of this theoretical framework. Over 11 months, 251 hr of behavioral observations and 296 fecal samples were collected from seven adult males in the Middle Atlas Mountains, Morocco. Fecal androgen levels rose before the onset of the mating season, during a period of rank instability, and were positively related to group mating activity across the mating season. Androgen levels were unrelated to rates of male-male aggression in any period, but higher ranked males had higher levels in both the mating season and in the period of rank instability. Lower androgen levels were associated with increased rates of male-infant grooming during the mating and unstable periods. Our results generally support the challenge hypothesis and highlight the importance of considering individual species' behavioral ecology when testing this framework. © 2017 Wiley Periodicals, Inc.

Infants Prefer Female Body Phenotypes; Infant Girls Prefer They Have an Hourglass Shape

PubMed Central

Alexander, Gerianne M.; Hawkins, Laura B.; Wilcox, Teresa; Hirshkowitz, Amy

2016-01-01

Adolescents and adults show preferences for male and female body shapes consistent with evolutionary theories of reproductive fitness and mate selection. However, when these preferences for females with narrow waists (i.e., 0.7 waist-to-hip ratio) and men with broad shoulders (i.e., mesomorphic body shape) emerge during the lifespan is largely unknown. To address this knowledge gap, eye-movements were tracked in 146 infants (3–18 months of age) during computer presentation of three-dimensional human figures varying in body features thought relevant for reproductive success (e.g., secondary sex characteristics, waist-to-hip ratio). When presented with pairs of figures differing in apparent sex, male and female infants looked significantly longer at the female figure compared to the male figure, a new finding that extends previous research showing preferences for female faces in infancy. When presented with same-sex figures differing in characteristics associated with mate value, male and female infants looked longer at a low mate value male (i.e., an endomorphic body type) compared to a high mate value male (i.e., a mesomorphic body type), a finding that replicates the results of previous research. In addition, the novel use of high and low mate value female figures showed a sex difference in visual attention, such that female infants looked longer at the high mate value female figure compared to the low mate female figure whereas male infants showed the opposite pattern of results. In sum, these findings suggest that infants generally do not possess preferences for adult-defined attractive male body shapes. However, infant girls’ greater attention to a female figure with an adult-preferred waist-to-hip ratio raises the possibility that evolved preferences for 0.7 waist-to-hip ratio influence girls’ later preference for toys representing females with an hourglass shape, perhaps supporting elaboration of adult social behaviors that enhance reproductive success (e.g., cooperative breeding). PMID:27375509

The scent of inbreeding: a male sex pheromone betrays inbred males

PubMed Central

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

Effects of assortative mate choice on the genomic and morphological structure of a hybrid zone between two bird subspecies.

PubMed

Semenov, Georgy A; Scordato, Elizabeth S C; Khaydarov, David R; Smith, Chris C R; Kane, Nolan C; Safran, Rebecca J

2017-11-01

Phenotypic differentiation plays an important role in the formation and maintenance of reproductive barriers. In some cases, variation in a few key aspects of phenotype can promote and maintain divergence; hence, the identification of these traits and their associations with patterns of genomic divergence is crucial for understanding the patterns and processes of population differentiation. We studied hybridization between the alba and personata subspecies of the white wagtail (Motacilla alba), and quantified divergence and introgression of multiple morphological traits and 19,437 SNP loci on a 3,000 km transect. Our goal was to identify traits that may contribute to reproductive barriers and to assess how variation in these traits corresponds to patterns of genome-wide divergence. Variation in only one trait-head plumage patterning-was consistent with reproductive isolation. Transitions in head plumage were steep and occurred over otherwise morphologically and genetically homogeneous populations, whereas cline centres for other traits and genomic ancestry were displaced over 100 km from the head cline. Field observational data show that social pairs mated assortatively by head plumage, suggesting that these phenotypes are maintained by divergent mating preferences. In contrast, variation in all other traits and genetic markers could be explained by neutral diffusion, although weak ecological selection cannot be ruled out. Our results emphasize that assortative mating may maintain phenotypic differences independent of other processes shaping genome-wide variation, consistent with other recent findings that raise questions about the relative importance of mate choice, ecological selection and selectively neutral processes for divergent evolution. © 2017 John Wiley & Sons Ltd.

Sexual selection is influenced by both developmental and adult environments.

PubMed

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.

Frequency dependence in matings with water-borne sperm.

PubMed

Pemberton, A J; Noble, L R; Bishop, J D D

2003-03-01

Negative frequency-dependent mating success--the rare male effect--is a potentially powerful evolutionary force, but disagreement exists as to whether previous work, focusing on copulating species, has robustly demonstrated this phenomenon. Noncopulating sessile organisms that release male gametes into the environment but retain their eggs for fertilization may routinely receive unequal mixtures of sperm. Although promiscuity seems unavoidable it does not follow that the resulting paternity obeys 'fair raffle' expectations. This study investigates frequency dependence in the mating of one such species, the colonial ascidian Diplosoma listerianum. In competition with an alternative sperm source males fathered more progeny if previously mated to a particular female than if no mating history existed. This suggests positive frequency-dependent selection, but may simply result from a mate order effect involving sperm storage. With fewer acclimation matings, separated by longer intervals, this pattern was not found. When, in a different experimental design, virgin females were given simultaneous mixtures of gametes at widely divergent concentrations, sperm at the lower frequency consistently achieved a greater than expected share of paternity--a rare male effect. A convincing argument as to why D. listerianum should favour rare sperm has not been identified, as sperm rarity is expected to correlate very poorly with ecological or genetic male characteristics in this pattern of mating. The existence of nongenetic female preferences at the level of colony modules, analogous in effect to fixed female preferences, is proposed. If visible to selection, indirect benefits from increasing the genetic diversity of a sibship appear the only likely explanation of the rare male effect in this system as the life history presents virtually no costs to multiple mating, and a near absence of direct (resource) benefits, whereas less controversial hypotheses of female promiscuity (e.g. trade up, genetic incompatibility) do not seem appropriate.

Clarifying Baker's Law

PubMed Central

Cheptou, P.-O.

2012-01-01

Background Baker's Law states that colonization by self-compatible organisms is more likely to be successful than colonization by self-incompatible organisms because of the ability for self-compatible organisms to produce offspring without pollination agents. This simple model has proved very successful in plant ecology and has been applied to various contexts, including colonizing or ruderal species, islands colonizers, invasive species or mating system variation across distribution ranges. Moreover, it is one of the only models in population biology linking two traits of major importance in ecology, namely dispersal and mating system. Although Baker's Law has stimulated a large number of empirical studies reporting the association of self-fertilization and colonizing ability in various contexts, the data have not established a general pattern for the association of traits. Scope In this paper, a critical position is adopted to discuss and clarify Baker's Law. From the literature referring to Baker's Law, an analysis made regarding how mating success is considered in such studies and discrepancies with population genetics theory of mating systems are highlighted. The data reporting the association of self-fertilization and colonizing ability are also briefly reviewed and the potential bias in interpretation is discussed. Lastly, a recent theoretical model analysing the link between colonizing ability and self-fertilization is considered. Conclusions Evolutionary predictions are actually more complex than Baker's intuitive arguments. It appears that Baker's Law encompasses a variety of ecological scenarios, which cannot be considered a priori as equivalent. Questioning what has been considered as self-evident for more than 50 years seems a reasonable objective to analyse in-depth dispersal and mating system traits. PMID:21685434

Mate choice and body pattern variations in the Crown Butterfly fish Chaetodon paucifasciatus (Chaetodontidae)

PubMed Central

Levy, Keren; Lerner, Amit; Shashar, Nadav

2014-01-01

ABSTRACT Mate choice is an important ecological behavior in fish, and is often based on visual cues of body patterns. The Crown Butterfly fish Chaetodon paucifasciatus (Chaetodontidae) is a monogamist, territorial species; it swims in close proximity to its partner throughout most of its life. This species is characterized by a pattern of 6–8 vertical black stripes on a white background, on both sides of its body. Our aim was to define spatial features (variations) in body patterns by evaluating the level of dissimilarity between both sides of each individual fish, and the level of dissimilarity between patterns of different individuals. In addition, we tested whether the fish are attracted to or reject specific features of the body patterns. Features were defined and counted using photographs of body patterns. Attraction to or rejection of specific features were tested behaviorally using a dual-choice experiment of video animations of individuals swimming over a coral-reef background. We found that the patterns of each fish and sides of the body were no less dissimilar, compared intraspecificly to other fish, and that each side pattern was unique and distinguishable. Variations in the patterns occurred mostly in the last three posterior stripes. Individuals were mainly attracted to conspecifics with multiple crossing patterns (two or more consecutive crossings), and rejected patterns with holes. Our results suggest that in this species the unique body pattern of each fish is used for conspecific identification of mates and intruders. PMID:25432516

Size and competitive mating success in the yeast Saccharomyces cerevisiae.

PubMed

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.

Marriage-Market Constraints and Mate-Selection Behavior: Racial, Ethnic, and Gender Differences in Intermarriage

PubMed Central

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

ASSORTATIVE MATING CAN IMPEDE OR FACILITATE FIXATION OF UNDERDOMINANT ALLELES

PubMed Central

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

Intraspecific evidence from guppies for correlated patterns of male and female genital trait diversification

PubMed Central

Evans, Jonathan P.; Gasparini, Clelia; Holwell, Gregory I.; Ramnarine, Indar W.; Pitcher, Trevor E.; Pilastro, Andrea

2011-01-01

The role of sexual selection in fuelling genital evolution is becoming increasingly apparent from comparative studies revealing interspecific divergence in male genitalia and evolutionary associations between male and female genital traits. Despite this, we know little about intraspecific variance in male genital morphology, or how male and female reproductive traits covary among divergent populations. Here we address both topics using natural populations of the guppy, Poecilia reticulata, a livebearing fish that exhibits divergent patterns of male sexual behaviour among populations. Initially, we performed a series of mating trials on a single population to examine the relationship between the morphology of the male's copulatory organ (the gonopodium) and the success of forced matings. Using a combination of linear measurements and geometric morphometrics, we found that variation in the length and shape of the gonopodium predicted the success of forced matings in terms of the rate of genital contacts and insemination success, respectively. We then looked for geographical divergence in these traits, since the relative frequency of forced matings tends to be greater in high-predation populations. We found consistent patterns of variation in male genital size and shape in relation to the level of predation, and corresponding patterns of (co)variation in female genital morphology. Together, these data enable us to draw tentative conclusions about the underlying selective pressures causing correlated patterns of divergence in male and female genital traits, which point to a role for sexually antagonistic selection. PMID:21270040

The mate recognition protein gene mediates reproductive isolation and speciation in the Brachionus plicatilis cryptic species complex.

PubMed

Gribble, Kristin E; Mark Welch, David B

2012-08-01

Chemically mediated prezygotic barriers to reproduction likely play an important role in speciation. In facultatively sexual monogonont rotifers from the Brachionus plicatilis cryptic species complex, mate recognition of females by males is mediated by the Mate Recognition Protein (MRP), a globular glycoprotein on the surface of females, encoded by the mmr-b gene family. In this study, we sequenced mmr-b copies from 27 isolates representing 11 phylotypes of the B. plicatilis species complex, examined the mode of evolution and selection of mmr-b, and determined the relationship between mmr-b genetic distance and mate recognition among isolates. Isolates of the B. plicatilis species complex have 1-4 copies of mmr-b, each composed of 2-9 nearly identical tandem repeats. The repeats within a gene copy are generally more similar than are gene copies among phylotypes, suggesting concerted evolution. Compared to housekeeping genes from the same isolates, mmr-b has accumulated only half as many synonymous differences but twice as many non-synonymous differences. Most of the amino acid differences between repeats appear to occur on the outer face of the protein, and these often result in changes in predicted patterns of phosphorylation. However, we found no evidence of positive selection driving these differences. Isolates with the most divergent copies were unable to mate with other isolates and rarely self-crossed. Overall the degree of mate recognition was significantly correlated with the genetic distance of mmr-b. Discrimination of compatible mates in the B. plicatilis species complex is determined by proteins encoded by closely related copies of a single gene, mmr-b. While concerted evolution of the tandem repeats in mmr-b may function to maintain identity, it can also lead to the rapid spread of a mutation through all copies in the genome and thus to reproductive isolation. The mmr-b gene is evolving rapidly, and novel alleles may be maintained and increase in frequency via asexual reproduction. Our analyses indicate that mate recognition, controlled by MMR-B, may drive reproductive isolation and allow saltational sympatric speciation within the B. plicatilis cryptic species complex, and that this process may be largely neutral.

"Monogamy" in Primates: Variability, Trends, and Synthesis: Introduction to special issue on Primate Monogamy.

PubMed

Díaz-Muñoz, Samuel L; Bales, Karen L

2016-03-01

This paper is the introduction to a special issue on "'Monogamy' in Primates: Variability, Trends, and Synthesis." The term "monogamy" has undergone redefinition over the years, and is now generally understood to refer to certain social characteristics rather than to genetic monogamy. However, even the term "social monogamy" is used loosely to refer to species which exhibit a spectrum of social structures, mating patterns, and breeding systems. Papers in this volume address key issues including whether or not our definitions of monogamy should change in order to better represent the social and mating behaviors that characterize wild primates; whether or not primate groups traditionally considered monogamous are actually so (by any definition); ways in which captive studies can contribute to our understanding of monogamy; and what selective pressures might have driven the evolution of monogamous and non-monogamous single female breeding systems. © 2015 Wiley Periodicals, Inc.

“Monogamy” in Primates: Variability, Trends and Synthesis

PubMed Central

Díaz-Muñoz, Samuel L.; Bales, Karen

2017-01-01

This paper is the introduction to a special issue on “'Monogamy' in Primates: Variability, Trends, and Synthesis”. The term “monogamy” has undergone redefinition over the years, and is now generally understood to refer to certain social characteristics rather than to genetic monogamy. However, even the term “social monogamy” is used loosely to refer to species which exhibit a spectrum of social structures, mating patterns, and breeding systems. Papers in this volume address key issues including whether or not our definitions of monogamy should change in order to better represent the social and mating behaviors that characterize wild primates; whether or not primate groups traditionally considered monogamous are actually so (by any definition); ways in which captive studies can contribute to our understanding of monogamy; and what selective pressures might have driven the evolution of monogamous and nonmonogamous single female breeding systems. PMID:26317875

Limited genomic consequences of mixed mating in the recently derived sister species pair, Collinsia concolor and Collinsia parryi.

PubMed

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.

Mates but not sexes differ in migratory niche in a monogamous penguin species.

PubMed

Thiebot, Jean-Baptiste; Bost, Charles-André; Dehnhard, Nina; Demongin, Laurent; Eens, Marcel; Lepoint, Gilles; Cherel, Yves; Poisbleau, Maud

2015-09-01

Strong pair bonds generally increase fitness in monogamous organisms, but may also underlie the risk of hampering it when re-pairing fails after the winter season. We investigated whether partners would either maintain contact or offset this risk by exploiting sex-specific favourable niches during winter in a migratory monogamous seabird, the southern rockhopper penguin Eudyptes chrysocome. Using light-based geolocation, we show that although the spatial distribution of both sexes largely overlapped, pair-wise mates were located on average 595 ± 260 km (and up to 2500 km) apart during winter. Stable isotope data also indicated a marked overlap between sex-specific isotopic niches (δ¹³C and δ¹⁵N values) but a segregation of the feeding habitats (δ¹³C values) within pairs. Importantly, the tracked females remained longer (12 days) at sea than males, but all re-mated with their previous partners after winter. Our study provides multiple evidence that migratory species may well demonstrate pair-wise segregation even in the absence of sex-specific winter niches (spatial and isotopic). We suggest that dispersive migration patterns with sex-biased timings may be a sufficient proximal cause for generating such a situation in migratory animals.

Religious Attendance as Reproductive Support

PubMed Central

Weeden, Jason; Cohen, Adam B.; Kenrick, Douglas T.

2009-01-01

We argue that a central function of religious attendance in the contemporary U.S. is to support a high-fertility, monogamous mating strategy. Although religious attendance is correlated with many demographic, personality, moral, and behavioral variables, we propose that sexual and family variables are at the core of many of these relationships. Numerous researchers have assumed that religious socialization causes people to feel moral reactions and engage in behaviors promoted by religious groups. On our view, mating preferences are centrally involved in individual differences in attraction to religious groups. In a sample of 21,131 individuals who participated in the U.S. General Social Survey, sexual behaviors were the relatively strongest predictors of religious attendance, even after controlling for age and gender. Effects of age and gender on religious attendance were weaker, and substantially reduced when controlling for sexual and family patterns. A sample of 902 college students provided more detailed information on religious, moral, and sexual variables. Results suggest that 1) moral views about sexual behavior are more strongly linked to religious attendance than other moral issues, and 2) mating strategy is more powerful than standard personality variables in predicting religious attendance. These findings suggest that reproductive strategies are at the heart of variations in religious attendance. PMID:21874105

Spiral groove seal. [for hydraulic rotating shaft

NASA Technical Reports Server (NTRS)

Ludwig, L. P. (Inventor)

1973-01-01

Mating flat surfaces inhibit leakage of a fluid around a stationary shaft. A spiral groove pattern produces a pumping action toward the fluid when the shaft rotates which prevents leakage while a generated hydraulic lifting force separates the mating surfaces to minimize wear.

Sex and the single (-eared) female: leg function, limb autotomy and mating history trade-offs in field crickets (Gryllus bimaculatus)

PubMed Central

Bateman, Philip W; Fleming, Patricia A

2005-01-01

Both male and female field crickets (Gryllus bimaculatus) autotomize front (tympanal) limbs more slowly than hind limbs. Arguably, this pattern could reflect possible differences in the mechanism of limb autotomy. However, we demonstrate that, for females, limb autotomy is also dependent on their mating status: virgin females autotomize front legs significantly more slowly than mated females. This response suggests a central control for leg autotomy in these animals, and less readiness to autotomize a front leg, possibly because the tympanum is crucial for mate location. PMID:17148319

Aggregate age-at-marriage patterns from individual mate-search heuristics.

PubMed

Todd, Peter M; Billari, Francesco C; Simão, Jorge

2005-08-01

The distribution of age at first marriage shows well-known strong regularities across many countries and recent historical periods. We accounted for these patterns by developing agent-based models that simulate the aggregate behavior of individuals who are searching for marriage partners. Past models assumed fully rational agents with complete knowledge of the marriage market; our simulated agents used psychologically plausible simple heuristic mate search rules that adjust aspiration levels on the basis of a sequence of encounters with potential partners. Substantial individual variation must be included in the models to account for the demographically observed age-at-marriage patterns.

Understanding the genetic diversity, spatial genetic structure and mating system at the hierarchical levels of fruits and individuals of a continuous Theobroma cacao population from the Brazilian Amazon.

PubMed

Silva, C R S; Albuquerque, P S B; Ervedosa, F R; Mota, J W S; Figueira, A; Sebbenn, A M

2011-06-01

Understanding the mating patterns of populations of tree species is a key component of ex situ genetic conservation. In this study, we analysed the genetic diversity, spatial genetic structure (SGS) and mating system at the hierarchical levels of fruits and individuals as well as pollen dispersal patterns in a continuous population of Theobroma cacao in Pará State, Brazil. A total of 156 individuals in a 0.56 ha plot were mapped and genotyped for nine microsatellite loci. For the mating system analyses, 50 seeds were collected from nine seed trees by sampling five fruits per tree (10 seeds per fruit). Among the 156 individuals, 127 had unique multilocus genotypes, and the remaining were clones. The population was spatially aggregated; it demonstrated a significant SGS up to 15 m that could be attributed primarily to the presence of clones. However, the short seed dispersal distance also contributed to this pattern. Population matings occurred mainly via outcrossing, but selfing was observed in some seed trees, which indicated the presence of individual variation for self-incompatibility. The matings were also correlated, especially within (Ρ(p(m))=0.607) rather than among the fruits (Ρ(p(m))=0.099), which suggested that a small number of pollen donors fertilised each fruit. The paternity analysis suggested a high proportion of pollen migration (61.3%), although within the plot, most of the pollen dispersal encompassed short distances (28 m). The determination of these novel parameters provides the fundamental information required to establish long-term ex situ conservation strategies for this important tropical species.

The impact of mating systems and dispersal on fine-scale genetic structure at maternally, paternally and biparentally inherited markers.

PubMed

Shaw, Robyn E; Banks, Sam C; Peakall, Rod

2018-01-01

For decades, studies have focused on how dispersal and mating systems influence genetic structure across populations or social groups. However, we still lack a thorough understanding of how these processes and their interaction shape spatial genetic patterns over a finer scale (tens-hundreds of metres). Using uniparentally inherited markers may help answer these questions, yet their potential has not been fully explored. Here, we use individual-level simulations to investigate the effects of dispersal and mating system on fine-scale genetic structure at autosomal, mitochondrial and Y chromosome markers. Using genetic spatial autocorrelation analysis, we found that dispersal was the major driver of fine-scale genetic structure across maternally, paternally and biparentally inherited markers. However, when dispersal was restricted (mean distance = 100 m), variation in mating behaviour created strong differences in the comparative level of structure detected at maternally and paternally inherited markers. Promiscuity reduced spatial genetic structure at Y chromosome loci (relative to monogamy), whereas structure increased under polygyny. In contrast, mitochondrial and autosomal markers were robust to differences in the specific mating system, although genetic structure increased across all markers when reproductive success was skewed towards fewer individuals. Comparing males and females at Y chromosome vs. mitochondrial markers, respectively, revealed that some mating systems can generate similar patterns to those expected under sex-biased dispersal. This demonstrates the need for caution when inferring ecological and behavioural processes from genetic results. Comparing patterns between the sexes, across a range of marker types, may help us tease apart the processes shaping fine-scale genetic structure. © 2017 John Wiley & Sons Ltd.

Understanding the genetic diversity, spatial genetic structure and mating system at the hierarchical levels of fruits and individuals of a continuous Theobroma cacao population from the Brazilian Amazon

PubMed Central

Silva, C R S; Albuquerque, P S B; Ervedosa, F R; Mota, J W S; Figueira, A; Sebbenn, A M

2011-01-01

Understanding the mating patterns of populations of tree species is a key component of ex situ genetic conservation. In this study, we analysed the genetic diversity, spatial genetic structure (SGS) and mating system at the hierarchical levels of fruits and individuals as well as pollen dispersal patterns in a continuous population of Theobroma cacao in Pará State, Brazil. A total of 156 individuals in a 0.56 ha plot were mapped and genotyped for nine microsatellite loci. For the mating system analyses, 50 seeds were collected from nine seed trees by sampling five fruits per tree (10 seeds per fruit). Among the 156 individuals, 127 had unique multilocus genotypes, and the remaining were clones. The population was spatially aggregated; it demonstrated a significant SGS up to 15 m that could be attributed primarily to the presence of clones. However, the short seed dispersal distance also contributed to this pattern. Population matings occurred mainly via outcrossing, but selfing was observed in some seed trees, which indicated the presence of individual variation for self-incompatibility. The matings were also correlated, especially within (r̂p(m)=0.607) rather than among the fruits (r̂p(m)=0.099), which suggested that a small number of pollen donors fertilised each fruit. The paternity analysis suggested a high proportion of pollen migration (61.3%), although within the plot, most of the pollen dispersal encompassed short distances (28 m). The determination of these novel parameters provides the fundamental information required to establish long-term ex situ conservation strategies for this important tropical species. PMID:21139632

Dispersal and survival of a polygynandrous passerine

USGS Publications Warehouse

Craig, Heather R.; Kendall, Steve J.; Wild, Teri C.; Powell, Abby N.

2015-01-01

Although sex biases in survival and dispersal are thought to be linked to avian mating systems, little is known about these demographic patterns in less common mating strategies such as polygynandry. We investigated breeding-site fidelity, natal philopatry, and apparent survival of the polygynandrous Smith's Longspur (Calcarius pictus) over a 7-yr period at 2 areas in Alaska's Brooks Range. We used capture–recapture histories of 243 color-banded adults and 431 juveniles to estimate annual survival and determined dispersal patterns from 34 adults that were found breeding within the study areas over multiple years. Most adults (88%) returned to nest in the same breeding neighborhood as in previous years; mean dispersal distance was 300.9 ± 74.2 m and did not differ between sexes. Juveniles exhibited low natal philopatry; only 4% of banded hatch-year birds were resighted as adults during subsequent years. Those that did return dispersed, on average, 1,674.4 ± 465.8 m from their natal nests (n = 6). Model-averaged survival estimates indicated that annual survival of adult females (50–58%) was only slightly lower than that of males (60–63%); juvenile survival was 41% but was paired with a low (13%) encounter probability. We attribute the lack of sex bias in adult dispersal to this species' polygynandrous mating strategy. Within this system, there are multiple mates within a breeding neighborhood. We argue that natural selection may favor females that remain on the same, familiar breeding site, because they do not have to disperse to a new area to find a suitable mate. Dispersal among breeding populations most likely occurs by juveniles returning as adults. Our findings support hypotheses that suggest a relationship between dispersal and mating strategy and provide some of the first insight into the demographic patterns of a polygynandrous passerine.

Sexual size dimorphism, canine dimorphism, and male-male competition in primates: where do humans fit in?

PubMed

Plavcan, J Michael

2012-03-01

Sexual size dimorphism is generally associated with sexual selection via agonistic male competition in nonhuman primates. These primate models play an important role in understanding the origins and evolution of human behavior. Human size dimorphism is often hypothesized to be associated with high rates of male violence and polygyny. This raises the question of whether human dimorphism and patterns of male violence are inherited from a common ancestor with chimpanzees or are uniquely derived. Here I review patterns of, and causal models for, dimorphism in humans and other primates. While dimorphism in primates is associated with agonistic male mate competition, a variety of factors can affect male and female size, and thereby dimorphism. The causes of human sexual size dimorphism are uncertain, and could involve several non-mutually-exclusive mechanisms, such as mate competition, resource competition, intergroup violence, and female choice. A phylogenetic reconstruction of the evolution of dimorphism, including fossil hominins, indicates that the modern human condition is derived. This suggests that at least some behavioral similarities with Pan associated with dimorphism may have arisen independently, and not directly from a common ancestor.

Sperm competition games when males invest in paternal care.

PubMed

Requena, Gustavo S; Alonzo, Suzanne H

2017-08-16

Sperm competition games investigate how males partition limited resources between pre- and post-copulatory competition. Although extensive research has explored how various aspects of mating systems affect this allocation, male allocation between mating, fertilization and parental effort has not previously been considered. Yet, paternal care can be energetically expensive and males are generally predicted to adjust their parental effort in response to expected paternity. Here, we incorporate parental effort into sperm competition games, particularly exploring how the relationship between paternal care and offspring survival affects sperm competition and the relationship between paternity and paternal care. Our results support existing expectations that (i) fertilization effort should increase with female promiscuity and (ii) paternal care should increase with expected paternity. However, our analyses also reveal that the cost of male care can drive the strength of these patterns. When paternal behaviour is energetically costly, increased allocation to parental effort constrains allocation to fertilization effort. As paternal care becomes less costly, the association between paternity and paternal care weakens and may even be absent. By explicitly considering variation in sperm competition and the cost of male care, our model provides an integrative framework for predicting the interaction between paternal care and patterns of paternity. © 2017 The Author(s).

'Good genes as heterozygosity': the major histocompatibility complex and mate choice in Atlantic salmon (Salmo salar).

PubMed

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.

How females of chirping and trilling field crickets integrate the 'what' and 'where' of male acoustic signals during decision making.

PubMed

Gabel, Eileen; Gray, David A; Matthias Hennig, R

2016-11-01

In crickets acoustic communication serves mate selection. Female crickets have to perceive and integrate male cues relevant for mate choice while confronted with several different signals in an acoustically diverse background. Overall female decisions are based on the attractiveness of the temporal pattern (informative about the 'what') and on signal intensity (informative about the 'where') of male calling songs. Here, we investigated how the relevant cues for mate choice are integrated during the decision process by females of five different species of chirping and trilling field crickets. Using a behavioral design, female preferences in no-choice and choice situations for male calling songs differing in pulse rate, modulation depth, intensities, chirp/trill arrangements and temporal shifts were examined. Sensory processing underlying decisions in female field crickets is rather similar as combined evidence suggested that incoming song patterns were analyzed separately by bilaterally paired networks for pattern attractiveness and pattern intensity. A downstream gain control mechanism leads to a weighting of the intensity cue by pattern attractiveness. While remarkable differences between species were observed with respect to specific processing steps, closely related species exhibited more similar preferences than did more distantly related species.

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.

Female Choice Undermines the Emergence of Strong Sexual Isolation between Locally Adapted Populations of Atlantic Mollies (Poecilia mexicana)

PubMed Central

Zimmer, Claudia; Bierbach, David; Arias-Rodriguez, Lenin; Plath, Martin

2018-01-01

Divergent selection between ecologically dissimilar habitats promotes local adaptation, which can lead to reproductive isolation (RI). Populations in the Poecilia mexicana species complex have independently adapted to toxic hydrogen sulfide and show varying degrees of RI. Here, we examined the variation in the mate choice component of prezygotic RI. Mate choice tests across drainages (with stimulus males from another drainage) suggest that specific features of the males coupled with a general female preference for yellow color patterns explain the observed variation. Analyses of male body coloration identified the intensity of yellow fin coloration as a strong candidate to explain this pattern, and common-garden rearing suggested heritable population differences. Male sexual ornamentation apparently evolved differently across sulfide-adapted populations, for example because of differences in natural counterselection via predation. The ubiquitous preference for yellow color ornaments in poeciliid females likely undermines the emergence of strong RI, as female discrimination in favor of own males becomes weaker when yellow fin coloration in the respective sulfide ecotype increases. Our study illustrates the complexity of the (partly non-parallel) pathways to divergence among replicated ecological gradients. We suggest that future work should identify the genomic loci involved in the pattern reported here, making use of the increasing genomic and transcriptomic datasets available for our study system. PMID:29724050

Reproductive Incompatibility Involving Senegalese Aedes aegypti (L) Is Associated with Chromosome Rearrangements

PubMed Central

Dickson, Laura B.; Sharakhova, Maria V.; Timoshevskiy, Vladimir A.; Fleming, Karen L.; Caspary, Alex; Sylla, Massamba; Black, William C.

2016-01-01

Aedes aegypti, the primary vector of dengue, yellow fever and Zika flaviviruses, consists of at least two subspecies. Aedes aegypti (Aaa) is light in color, has pale scales on the first abdominal tergite, oviposits in artificial containers, and preferentially feeds on humans. Aedes aegypti formosus (Aaf), has a dark cuticle, is restricted to sub-Saharan Africa, has no pale scales on the first abdominal tergite and frequently oviposits in natural containers. Scale patterns correlate with cuticle color in East Africa but not in Senegal, West Africa where black cuticle mosquitoes display a continuum of scaling patterns and breed domestically indoors. An earlier laboratory study did not indicate any pre- or postzygotic barriers to gene flow between Aaa and Aaf in East Africa. However, similar attempts to construct F1 intercross families between Aaa laboratory strains and Senegal Ae. aegypti (SenAae) failed due to poor F1 oviposition and low F2 egg-to-adult survival. Insemination and assortative mating experiments failed to identify prezygotic mating barriers. Backcrosses were performed to test for postzygotic isolation patterns consistent with Haldane’s rule modified for species, like Aedes, that have an autosomal sex determining locus (SDL). Egg-pupal survival was predicted to be low in females mated to hybrid F1 males but average when a male mates with a hybrid F1 female. Survival was in fact significantly reduced when females mated to hybrid males but egg-pupal survival was significantly increased when males were mated to hybrid F1 females. These observations are therefore inconclusive with regards to Haldane’s rule. Basic cytogenetic analyses and Fluorescent In Situ Hybridization (FISH) experiments were performed to compare SenAae strains with the IB12 strain of Aaa that was used for genome sequencing and physical mapping. Some SenAae strains had longer chromosomes than IB12 and significantly different centromeric indices on chromosomes 1 and 3. DAPI staining was used to identify AT-rich regions, chromomycin A3 following pretreatment with barium hydroxide stained for GC-rich regions and stained the ribosomal RNA locus and YOYO-1 was used to test for differential staining. Chromosome patterns in SenAae strains revealed by these three stains differed from those in IB12. For FISH, 40 BAC clones previously physically mapped on Aaa chromosomes were used to test for chromosome rearrangements in SenAae relative to IB12. Differences in the order of markers identified two chromosomal rearrangements between IB12 and SenAae strains. The first rearrangement involves two overlapping pericentric (containing the centromere) inversions in chromosome 3 or an insertion of a large fragment into the 3q arm. The second rearrangement is close to the centromere on the p arm of chromosome 2. Linkage analysis of the SDL and the white-eye locus identified a likely chromosomal rearrangement on chromosome 1. The reproductive incompatibility observed within SenAae and between SenAae and Aaa may be generally associated with chromosome rearrangements on all three chromosomes and specifically caused by pericentric inversions on chromosomes 2 and 3. PMID:27105225

The evolution of mate choice: a dialogue between theory and experiment.

PubMed

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.

Mate Selection among Married and Cohabiting Couples.

ERIC Educational Resources Information Center

Blackwell, Debra L.; Lichter, Daniel T.

2000-01-01

Examines comparative patterns of educational and racial assortative mating or homogany among married and cohabiting couples, and evaluates whether women and men trade in socioeconomic status and racial caste prestige. Lists several findings, including married/cohabiting couples are highly homogenous with respect to race and education. Suggests…

General view of the Orbiter Discovery mated to the External ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of the Orbiter Discovery mated to the External Tank and Solid Rocket Booster assembly in the Vehicle Assembly Building at Kennedy Space Center - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Mate retention behavior of men and women in heterosexual and homosexual relationships.

PubMed

Vanderlaan, Doug P; Vasey, Paul L

2008-08-01

Comparing the behavior of heterosexual and homosexual persons can provide insight into the origins of heterosexual sex differences in psychology. Evidence indicates that, aside from sexual partner preference, the mating psychology of homosexual men is sex-typical whereas that of homosexual women tends to be more sex-atypical. The current study examined one aspect of mating psychology, mate retention behavior, and tested whether homosexual men and women were sex-typical or sex-atypical for those mate retention tactics where heterosexual men and women differed. Men and women in heterosexual and homosexual relationships were asked to provide information regarding their partners' mate retention behavior by using the Mate Retention Inventory Questionnaire. Heterosexual men and women differed significantly for six of the 19 mate retention tactics considered. With respect to the six mate retention tactics where heterosexual sex differences existed, homosexual men behaved in a sex-typical manner for five of the tactics, whereas homosexual women behaved in a sex-atypical manner for all six tactics. We discuss the significance of these findings for explaining the origins of the mate retention behavior of heterosexual men and women. In addition, we consider what the pattern of sex-typical and sex-atypical mating psychology among homosexual men and women, respectively, suggests in regard to sex differences in the development of mating psychology and the development of homosexual persons.

Negative-assortative mating for color in wolves.

PubMed

Hedrick, Philip W; Smith, Douglas W; Stahler, Daniel R

2016-04-01

There is strong negative-assortative mating for gray and black pelage color in the iconic wolves in Yellowstone National Park. This is the first documented case of significant negative-assortative mating in mammals and one of only a very few cases in vertebrates. Of 261 matings documented from 1995 to 2015, 63.6% were between gray and black wolves and the correlation between mates for color was -0.266. There was a similar excess of matings of both gray males × black females and black males × gray females. Using the observed frequency of negative-assortative mating in a model with both random and negative-assortative mating, the estimated proportion of negative-assortative mating was 0.430. The estimated frequency of black wolves in the population from 1996 to 2014 was 0.452 and these frequencies appear stable over this 19-year period. Using the estimated level of negative-assortative mating, the predicted equilibrium frequency of the dominant allele was 0.278, very close to the mean value of 0.253 observed. In addition, the patterns of genotype frequencies, that is, the observed proportion of black homozygotes and the observed excess of black heterozygotes, are consistent with negative-assortative mating. Importantly these results demonstrate that negative-assortative mating could be entirely responsible for the maintenance of this well-known color polymorphism. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Prioritization of Potential Mates' History of Sexual Fidelity During a Conjoint Ranking Task.

PubMed

Mogilski, Justin K; Wade, T Joel; Welling, Lisa L M

2014-07-01

This series of studies is the first to use conjoint analysis to examine how individuals make trade-offs during mate selection when provided information about a partner's history of sexual infidelity. Across three studies, participants ranked profiles of potential mates, with each profile varying across five attributes: financial stability, physical attractiveness, sexual fidelity, emotional investment, and similarity. They also rated each attribute separately for importance in an ideal mate. Overall, we found that for a long-term mate, participants prioritized a potential partner's history of sexual fidelity over other attributes when profiles were ranked conjointly. For a short-term mate, sexual fidelity, physical attractiveness, and financial stability were equally important, and each was more important than emotional investment and similarity. These patterns contrast with participants' self-reported importance ratings of each individual attribute. Our results are interpreted within the context of previous literature examining how making trade-offs affect mate selection. © 2014 by the Society for Personality and Social Psychology, Inc.

Assortative mating can impede or facilitate fixation of underdominant alleles.

PubMed

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.

When the difference is in the details: a critique of Zentner and Mitura (2012) "Stepping out of the caveman's shadow: Nations' gender gap predicts degree of sex differentiation in mate preferences".

PubMed

Schmitt, David P

2012-10-29

In a recent 10-nation study, Zentner and Mitura (2012) reported observing smaller sex differences in mate preferences within nations that have higher gender parity. As noted in previous research, and in a re-analysis of Zentner and Mitura's own data, sex differences in some mate preferences (e.g., long-term mate preferences for physical attractiveness) are either unrelated to or actually get larger with higher national gender parity. It is critically important to distinguish among mate preference domains when looking for patterns of sexual differentiation across nations. Indeed, for many psychological domains (e.g., attachment styles, Big Five traits, Dark Triad traits, self-esteem, personal values, depression, emotional expression, crying behavior, intimate partner violence, tested mental abilities, health indicators; see Schmitt, 2012), sex differences are demonstrably larger in nations with higher sociopolitical gender parity. By not distinguishing among mate preferences, Zentner and Mitura committed a form of the ecological fallacy-making false conclusions about individual mate preferences when looking only at associations among groups of mate preferences.

Mate replacement entails a fitness cost for a socially monogamous seabird.

PubMed

Ismar, Stefanie M H; Daniel, Claire; Stephenson, Brent M; Hauber, Mark E

2010-01-01

Studies of the selective advantages of divorce in socially monogamous bird species have unravelled extensive variation among different lineages with diverse ecologies. We quantified the reproductive correlates of mate retention, mate loss and divorce in a highly philopatric, colonially breeding biparental seabird, the Australasian gannet Morus serrator. Estimates of annual divorce rates varied between 40-43% for M. serrator and were high in comparison with both the closely related Morus bassanus and the range of divorce rates reported across monogamous avian breeding systems. Mate retention across seasons was related to consistently higher reproductive success compared with mate replacement, while divorce per se contributed significantly to lower reproductive output only in one of two breeding seasons. Prior reproductive success was not predictive of mate replacement overall or divorce in particular. These patterns are in accordance with the musical chairs hypothesis of adaptive divorce theory, which operates in systems characterised by asynchronous territorial establishment.

Mate replacement entails a fitness cost for a socially monogamous seabird

NASA Astrophysics Data System (ADS)

Ismar, Stefanie M. H.; Daniel, Claire; Stephenson, Brent M.; Hauber, Mark E.

2010-01-01

Studies of the selective advantages of divorce in socially monogamous bird species have unravelled extensive variation among different lineages with diverse ecologies. We quantified the reproductive correlates of mate retention, mate loss and divorce in a highly philopatric, colonially breeding biparental seabird, the Australasian gannet Morus serrator. Estimates of annual divorce rates varied between 40-43% for M. serrator and were high in comparison with both the closely related Morus bassanus and the range of divorce rates reported across monogamous avian breeding systems. Mate retention across seasons was related to consistently higher reproductive success compared with mate replacement, while divorce per se contributed significantly to lower reproductive output only in one of two breeding seasons. Prior reproductive success was not predictive of mate replacement overall or divorce in particular. These patterns are in accordance with the musical chairs hypothesis of adaptive divorce theory, which operates in systems characterised by asynchronous territorial establishment.

Shifts in reproductive assurance strategies and inbreeding costs associated with habitat fragmentation in Central American mahogany

PubMed Central

Breed, Martin F; Gardner, Michael G; Ottewell, Kym M; Navarro, Carlos M; Lowe, Andrew J

2012-01-01

The influence of habitat fragmentation on mating patterns and progeny fitness in trees is critical for understanding the long-term impact of contemporary landscape change on the sustainability of biodiversity. We examined the relationship between mating patterns, using microsatellites, and fitness of progeny, in a common garden trial, for the insect-pollinated big-leaf mahogany, Swietenia macrophylla King, sourced from forests and isolated trees in 16 populations across Central America. As expected, isolated trees had disrupted mating patterns and reduced fitness. However, for dry provenances, fitness was negatively related to correlated paternity, while for mesic provenances, fitness was correlated positively with outcrossing rate and negatively with correlated paternity. Poorer performance of mesic provenances is likely because of reduced effective pollen donor density due to poorer environmental suitability and greater disturbance history. Our results demonstrate a differential shift in reproductive assurance and inbreeding costs in mahogany, driven by exploitation history and contemporary landscape context. PMID:22381041

Analysis of the Mediterranean fruit fly [Ceratitis capitata (Wiedemann)] spatio-temporal distribution in relation to sex and female mating status for precision IPM.

PubMed

Sciarretta, Andrea; Tabilio, Maria Rosaria; Lampazzi, Elena; Ceccaroli, Claudio; Colacci, Marco; Trematerra, Pasquale

2018-01-01

The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), is a key pest of fruit crops in many tropical, subtropical and mild temperate areas worldwide. The economic importance of this fruit fly is increasing due to its invasion of new geographical areas. Efficient control and eradication efforts require adequate information regarding C. capitata adults in relation to environmental and physiological cues. This would allow effective characterisation of the population spatio-temporal dynamic of the C. capitata population at both the orchard level and the area-wide landscape. The aim of this study was to analyse population patterns of adult medflies caught using two trapping systems in a peach orchard located in central Italy. They were differentiated by adult sex (males or females) and mating status of females (unmated or mated females) to determine the spatio-temporal dynamic and evaluate the effect of cultivar and chemical treatments on trap catches. Female mating status was assessed by spermathecal dissection and a blind test was carried out to evaluate the reliability of the technique. Geostatistical methods, variogram and kriging, were used to produce distributional maps. Results showed a strong correlation between the distribution of males and unmated females, whereas males versus mated females and unmated females versus mated females showed a lower correlation. Both cultivar and chemical treatments had significant effects on trap catches, showing associations with sex and female mating status. Medfly adults showed aggregated distributions in the experimental field, but hot spots locations varied. The spatial pattern of unmated females reflected that of males, whereas mated females were largely distributed around ripening or ripe fruit. The results give relevant insights into pest management. Mated females may be distributed differently to unmated females and the identification of male hot spots through monitoring would allow localisation of virgin female populations. Based on our results, a more precise IPM strategy, coupled with effective sanitation practices, could represent a more effective approach to medfly control.

Sexual and reproductive behaviour of Drosophila melanogaster from a microclimatically interslope differentiated population of "Evolution Canyon" (Mount Carmel, Israel).

PubMed

Iliadi, K; Iliadi, N; Rashkovetsky, E; Minkov, I; Nevo, E; Korol, A

2001-11-22

The strong microscale interslope environmental differences in "Evolution Canyon" provide an excellent natural model for sympatric speciation. Our previous studies revealed significant slope-specific differences for a fitness complex of Drosophila. This complex involved either adaptation traits (tolerance to high temperature, different viability and longevity pattern) or behavioural differentiation, manifested in habitat choice and non-random mating. This remarkable differentiation has evolved despite a very small interslope distance (a few hundred metres only). Our hypothesis is that strong interslope microclimatic contrast caused differential selection for fitness-related traits accompanied by behavioural differentiation and reinforced by some sexual isolation, which started incipient speciation. Here we describe the results of a systematic analysis of sexual behaviour in a non-choice situation and several reproductive parameters of D. melanogaster populations from the opposite slopes of "Evolution Canyon". The evidence indicates that: (i) mate choice derives from differences in mating propensity and discrimination; (ii) females from the milder north-facing slope discriminate strongly against males of the opposite slope; (iii) both sexes of the south-facing slope display distinct reproductive and behavioural patterns with females showing increased fecundity, shorter time before remating and relatively higher receptivity, and males showing higher mating propensity. These patterns represent adaptive life strategies contributing to higher fitness.

General view of the interior of the Vehicle Assembly Building ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of the interior of the Vehicle Assembly Building showing the External Tank mated to the Solid Rocket Boosters awaiting the arrival and mating of the Orbiter Discovery. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Fungal Sex: The Basidiomycota.

PubMed

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.

Model-assisted template extraction SRAF application to contact holes patterns in high-end flash memory device fabrication

NASA Astrophysics Data System (ADS)

Seoud, Ahmed; Kim, Juhwan; Ma, Yuansheng; Jayaram, Srividya; Hong, Le; Chae, Gyu-Yeol; Lee, Jeong-Woo; Park, Dae-Jin; Yune, Hyoung-Soon; Oh, Se-Young; Park, Chan-Ha

2018-03-01

Sub-resolution assist feature (SRAF) insertion techniques have been effectively used for a long time now to increase process latitude in the lithography patterning process. Rule-based SRAF and model-based SRAF are complementary solutions, and each has its own benefits, depending on the objectives of applications and the criticality of the impact on manufacturing yield, efficiency, and productivity. Rule-based SRAF provides superior geometric output consistency and faster runtime performance, but the associated recipe development time can be of concern. Model-based SRAF provides better coverage for more complicated pattern structures in terms of shapes and sizes, with considerably less time required for recipe development, although consistency and performance may be impacted. In this paper, we introduce a new model-assisted template extraction (MATE) SRAF solution, which employs decision tree learning in a model-based solution to provide the benefits of both rule-based and model-based SRAF insertion approaches. The MATE solution is designed to automate the creation of rules/templates for SRAF insertion, and is based on the SRAF placement predicted by model-based solutions. The MATE SRAF recipe provides optimum lithographic quality in relation to various manufacturing aspects in a very short time, compared to traditional methods of rule optimization. Experiments were done using memory device pattern layouts to compare the MATE solution to existing model-based SRAF and pixelated SRAF approaches, based on lithographic process window quality, runtime performance, and geometric output consistency.

Evidence for Female-Biased Dispersal in the Protandrous Hermaphroditic Asian Seabass, Lates calcarifer

PubMed Central

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

Evidence for female-biased dispersal in the protandrous hermaphroditic Asian Seabass, Lates calcarifer.

PubMed

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.

Sexual signals and mating patterns in Syngnathidae.

PubMed

Rosenqvist, G; Berglund, A

2011-06-01

Male pregnancy in the family Syngnathidae (pipefishes, seahorses and seadragons) predisposes males to limit female reproductive success; sexual selection may then operate more strongly on females and female sexual signals may evolve (sex-role reversal). A bewildering array of female signals has evolved in Syngnathids, e.g. skin folds, large body size, colouration, markings on the body and elaborate courtship. These female sexual signals do not seem quantitatively or qualitatively different from those that evolve in males in species with conventional sex roles where males provide females or offspring with direct benefits. In several syngnathid species, males also evolve ornaments, females are choosy in addition to being competitive and males compete as well as choosing partners. Thus, sex roles form a continuum, spanning from conventional to reversed within this group of fishes. Cases are presented here suggesting that stronger sexual selection on females may be most extreme in species showing classical polyandry (one male mates with several females, such as many species where males brood their eggs on the trunk), intermediate in polygynandrous species (males and females both mate with more than one partner, as in many species where males brood their eggs on the tail) and least extreme, even exhibiting conventional sex roles, in monogamous species (one male mates solely with one female, as in many seahorses and tropical pipefishes). At the same time caution is needed before unanimously establishing this pattern: first, the connection between mating patterns, strength of sexual selection, sex roles and ornament expression is far from simple and straightforward, and second, knowledge of the actual morphology, ecology and behaviour of most syngnathid species is scanty. Basically only a few Nerophis, Syngnathus and Hippocampus species have been studied in any detail. It is known, however, that this group of fishes exhibits a remarkable variation in sex roles and ornamentation, making them an ideal group for the study of mating patterns, sexual selection and sexually selected signals. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

Maternal effects on offspring depend on female mating pattern and offspring environment in yellow dung flies.

PubMed

Tregenza, Tom; Wedell, Nina; Hosken, David J; Ward, Paul I

2003-02-01

Direct costs and benefits to females of multiple mating have been shown to have large effects on female fecundity and longevity in several species. However, with the exception of studies examining genetic benefits of polyandry, little attention has been paid to the possible effects on offspring of multiple mating by females. We propose that nongenetic effects of maternal matings on offspring fitness are best viewed in the same context as other maternal phenotype effects on offspring that are well known even in species lacking parental care. Hence, matings can exert effects on offspring in the same way as other maternal environment variables, and are likely to interact with such effects. We have conducted a study using yellow dung flies (Scathophaga stercoraria), in which we independently manipulated female mating rate, number of mates and maternal thermal environment and measured subsequent fecundity, hatching success, and offspring life-history traits. To distinguish between direct effects of matings and potential genetic benefits of polyandry we split broods and reared offspring at three different temperature regimes. This allowed us to demonstrate that although we could not detect any simple benefits or costs to matings, there are effects of maternal environment on offspring and these effects interact with female mating regime affecting offspring fitness. Such interactions between female phenotype and the costs and benefits of matings have potentially broad implications for understanding female behavior.

Self-Perceived Mate Value, Facial Attractiveness, and Mate Preferences: Do Desirable Men Want It All?

PubMed

Arnocky, Steven

2018-01-01

Ten years ago, Buss and Shackelford demonstrated that high mate value (i.e., physically attractive) women held more discerning mate preferences relative to lower mate value women. Since then, researchers have begun to consider the equally important role of men's sexual selectivity in human mate choice. Yet, little research has focused on whether high mate value men are similarly choosy in their mate preferences. In a sample of 139 undergraduate men, relationships between self-perceived mate value as well as female-rated facial attractiveness were examined in relation to men's expressed mate preferences. Results showed that self-perceived mate value was unrelated to men's facial attractiveness as rated by women. Men who believed they were of high mate value were more likely than lower mate value men to prefer to marry at a younger age; to have a spouse who was younger than them; and to have a partner who was sociable, ambitious, high in social status, with good financial prospects, a desire for children, health, good looks, and mutual attraction. Objective male facial attractiveness was generally unrelated to heightened mate preferences, with the exception of heightened preference for similar religious background and good physical health. Findings suggest that men who perceive themselves as high in overall mate value are selective in their mate choice in a manner similar to high mate value women.

A dynamic game-theoretic model of parental care.

PubMed

Mcnamara, J M; Székely, T; Webb, J N; Houston, A I

2000-08-21

We present a model in which members of a mated pair decide whether to care for their offspring or desert them. There is a breeding season of finite length during which it is possible to produce and raise several batches of offspring. On deserting its offspring, an individual can search for a new mate. The probability of finding a mate depends on the number of individuals of each sex that are searching, which in turn depends upon the previous care and desertion decisions of all population members. We find the evolutionarily stable pattern of care over the breeding season. The feedback between behaviour and mating opportunity can result in a pattern of stable oscillations between different forms of care over the breeding season. Oscillations can also arise because the best thing for an individual to do at a particular time in the season depends on future behaviour of all population members. In the baseline model, a pair splits up after a breeding attempt, even if they both care for the offspring. In a version of the model in which a pair stays together if they both care, the feedback between behaviour and mating opportunity can lead to more than one evolutionarily stable form of care. Copyright 2000 Academic Press.

Mate-sampling costs and sexy sons.

PubMed

Kokko, H; Booksmythe, I; Jennions, M D

2015-01-01

Costly female mating preferences for purely Fisherian male traits (i.e. sexual ornaments that are genetically uncorrelated with inherent viability) are not expected to persist at equilibrium. The indirect benefit of producing 'sexy sons' (Fisher process) disappears: in some models, the male trait becomes fixed; in others, a range of male trait values persist, but a larger trait confers no net fitness advantage because it lowers survival. Insufficient indirect selection to counter the direct cost of producing fewer offspring means that preferences are lost. The only well-cited exception assumes biased mutation on male traits. The above findings generally assume constant direct selection against female preferences (i.e. fixed costs). We show that if mate-sampling costs are instead derived based on an explicit account of how females acquire mates, an initially costly mating preference can coevolve with a male trait so that both persist in the presence or absence of biased mutation. Our models predict that empirically detecting selection at equilibrium will be difficult, even if selection was responsible for the location of the current equilibrium. In general, it appears useful to integrate mate sampling theory with models of genetic consequences of mating preferences: being explicit about the process by which individuals select mates can alter equilibria. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Male resource defense mating system in primates? An experimental test in wild capuchin monkeys.

PubMed

Tiddi, Barbara; Heistermann, Michael; Fahy, Martin K; Wheeler, Brandon C

2018-01-01

Ecological models of mating systems provide a theoretical framework to predict the effect of the defendability of both breeding resources and mating partners on mating patterns. In resource-based mating systems, male control over breeding resources is tightly linked to female mating preference. To date, few field studies have experimentally investigated the relationship between male resource control and female mating preference in mammals due to difficulties in manipulating ecological factors (e.g., food contestability). We tested the within-group male resource defense hypothesis experimentally in a wild population of black capuchin monkeys (Sapajus nigritus) in Iguazú National Park, Argentina. Sapajus spp. represent an ideal study model as, in contrast to most primates, they have been previously argued to be characterized by female mate choice and a resource-based mating system in which within-group resource monopolization by high-ranking males drives female mating preference for those males. Here, we examined whether females (N = 12) showed a weaker preference for alpha males during mating seasons in which food distribution was experimentally manipulated to be less defendable relative to those in which it was highly defendable. Results did not support the within-group male resource defense hypothesis, as female sexual preferences for alpha males did not vary based on food defendability. We discuss possible reasons for our results, including the possibility of other direct and indirect benefits females receive in exercising mate choice, the potential lack of tolerance over food directed towards females by alpha males, and phylogenetic constraints.

Genetic compatibility, mate choice and patterns of parentage: invited review.

PubMed

Tregenza, T; Wedell, N

2000-08-01

There is growing interest in the possibility that genetic compatibility may drive mate choice, including gamete choice, particularly from the perspective of understanding why females frequently mate with more than one male. Mate choice for compatibility differs from other forms of choice for genetic benefits (such as 'good genes') because individuals are expected to differ in their mate preferences, changing the evolutionary dynamics of sexual selection. Recent experiments designed to investigate genetic benefits of polyandry suggest that mate choice on the basis of genetic compatibility may be widespread. However, in most systems the mechanisms responsible for variation in compatibility are unknown. We review potential sources of variation in genetic compatibility and whether there is any evidence for mate choice driven by these factors. Selfish genetic elements appear to have the potential to drive mate compatibility mate choice, though as yet there is only one convincing example. There is abundant evidence for assortative mating between populations in hybrid zones, but very few examples where this is clearly a result of selection against mating with genetically less compatible individuals. There are also numerous cases of inbreeding avoidance, but little evidence that mate choice or differential fertilization success driven by genetic compatibility occurs between unrelated individuals. The exceptions to this are a handful of situations where both the alleles causing incompatibility and the alleles involved in mate choice are located in a chromosome region where recombination is suppressed. As yet there are only a few potential sources of genetic compatibility which have clearly been shown to drive mate choice. This may reflect limitations in the potential for the evolution of mate choice for genetic compatibility within populations, although the most promising sources of such incompatibilities have received relatively little research.

Population Structure, Movement Patterns, and Frequency of Multiple Matings in Tenodera sinensis (Mantodea: Mantidae).

PubMed

Christensen, Tyler; Brown, William D

2018-04-14

Models of the evolution of sexual cannibalism show that the frequency of male mating opportunities has significant impact on male choice and male risk aversion. In this study, we examined ecological components that should affect opportunities for multiple mating in wild populations of the Chinese mantid (Tenodera sinensis Saussure). While conducting mark-recapture studies of two field populations over the course of two seasons, along with Global Positioning System data on locations of individuals, we collected data on population densities, movement patterns, and individual ranges to estimate the overlap of adult males and female mantids. Our results show that local populations of mantids range from 89 to 161 individuals and occur at densities ranging from 10 to 39 mantids per 1,000 m2. Males move greater distances daily compared with females, giving males larger home range sizes. The ranges of male mantids overlapped with multiple females, thus offering the potential for multiple mating by males. We directly observed 11 encounters between male and female T. sinensis, including one multiple mating by an individual male. The overall mate encounter rate for males was 12.5%. We also provide additional observations of interspecific sexual attraction between T. sinensis and Mantis religiosa Linne (Mantodea: Mantidae). Mantids were most commonly found within the top 20% of two flowering plants, goldenrod (Solidago Linnaeus spp. (Asterales: Asteraceae)) and mugwort (Artemisia vulgaris Linnaeus (Asterales: Asteraceae)), which should place them in prime locations for capturing flying pollinators.

A molecular analysis of African lion (Panthera leo) mating structure and extra-group paternity in Etosha National Park.

PubMed

Lyke, M M; Dubach, J; Briggs, M B

2013-05-01

The recent incorporation of molecular methods into analyses of social and mating systems has provided evidence that mating patterns often differ from those predicted by group social organization. Based on field studies and paternity analyses at a limited number of sites, African lions are predicted to exhibit a strict within-pride mating system. Extra-group paternity has not been previously reported in African lions; however, observations of extra-group associations among lions inhabiting Etosha National Park in Namibia suggest deviation from the predicted within-pride mating pattern. We analysed variation in 14 microsatellite loci in a population of 164 African lions in Etosha National Park. Genetic analysis was coupled with demographic and observational data to examine pride structure, relatedness and extra-group paternity (EGP). EGP was found to occur in 57% of prides where paternity was analysed (n = 7), and the overall rate of EGP in this population was 41% (n = 34). Group sex ratio had a significant effect on the occurrence of EGP (P < 0.05), indicating that variation in pride-level social structure may explain intergroup variation in EGP. Prides with a lower male-to-female ratio were significantly more likely to experience EGP in this population. The results of this study challenge the current models of African lion mating systems and provide evidence that social structure may not reflect breeding structure in some social mammals. © 2013 Blackwell Publishing Ltd.

The mate recognition protein gene mediates reproductive isolation and speciation in the Brachionus plicatilis cryptic species complex

PubMed Central

2012-01-01

Background Chemically mediated prezygotic barriers to reproduction likely play an important role in speciation. In facultatively sexual monogonont rotifers from the Brachionus plicatilis cryptic species complex, mate recognition of females by males is mediated by the Mate Recognition Protein (MRP), a globular glycoprotein on the surface of females, encoded by the mmr-b gene family. In this study, we sequenced mmr-b copies from 27 isolates representing 11 phylotypes of the B. plicatilis species complex, examined the mode of evolution and selection of mmr-b, and determined the relationship between mmr-b genetic distance and mate recognition among isolates. Results Isolates of the B. plicatilis species complex have 1–4 copies of mmr-b, each composed of 2–9 nearly identical tandem repeats. The repeats within a gene copy are generally more similar than are gene copies among phylotypes, suggesting concerted evolution. Compared to housekeeping genes from the same isolates, mmr-b has accumulated only half as many synonymous differences but twice as many non-synonymous differences. Most of the amino acid differences between repeats appear to occur on the outer face of the protein, and these often result in changes in predicted patterns of phosphorylation. However, we found no evidence of positive selection driving these differences. Isolates with the most divergent copies were unable to mate with other isolates and rarely self-crossed. Overall the degree of mate recognition was significantly correlated with the genetic distance of mmr-b. Conclusions Discrimination of compatible mates in the B. plicatilis species complex is determined by proteins encoded by closely related copies of a single gene, mmr-b. While concerted evolution of the tandem repeats in mmr-b may function to maintain identity, it can also lead to the rapid spread of a mutation through all copies in the genome and thus to reproductive isolation. The mmr-b gene is evolving rapidly, and novel alleles may be maintained and increase in frequency via asexual reproduction. Our analyses indicate that mate recognition, controlled by MMR-B, may drive reproductive isolation and allow saltational sympatric speciation within the B. plicatilis cryptic species complex, and that this process may be largely neutral. PMID:22852831

Strangers With Benefits: Attraction to Outgroup Men Increases as Fertility Increases Across the Menstrual Cycle.

PubMed

Salvatore, Joseph F; Meltzer, Andrea L; March, David S; Gaertner, Lowell

2017-02-01

Research typically reveals that outgroups are regarded with disinterest at best and hatred and enmity at worst. Working from an evolutionary framework, we identify a unique pattern of outgroup attraction. The small-group lifestyle of pre-human ancestors plausibly limited access to genetically diverse mates. Ancestral females may have solved the inbreeding dilemma while balancing parental investment pressures by mating with outgroup males either via converting to an outgroup or cuckolding the ingroup. A vestige of those mating strategies might manifest in human women as a cyclic pattern of attraction across the menstrual cycle, such that attraction to outgroup men increases as fertility increases across the cycle. Two studies, one using a longitudinal method and the other an experimental method, evidenced the hypothesized linear relationship between attraction to outgroup men and fertility in naturally cycling women.

Bateman's principles and human sex roles.

PubMed

Brown, Gillian R; Laland, Kevin N; Mulder, Monique Borgerhoff

2009-06-01

In 1948, Angus J. Bateman reported a stronger relationship between mating and reproductive success in male fruit flies compared with females, and concluded that selection should universally favour 'an undiscriminating eagerness in the males and a discriminating passivity in the females' to obtain mates. The conventional view of promiscuous, undiscriminating males and coy, choosy females has also been applied to our own species. Here, we challenge the view that evolutionary theory prescribes stereotyped sex roles in human beings, firstly by reviewing Bateman's principles and recent sexual selection theory and, secondly, by examining data on mating behaviour and reproductive success in current and historic human populations. We argue that human mating strategies are unlikely to conform to a single universal pattern.

MHC-correlated mate choice in humans: a review.

PubMed

Havlicek, Jan; Roberts, S Craig

2009-05-01

Extremely high variability in genes of the major histocompatibility complex (MHC) in vertebrates is assumed to be a consequence of frequency-dependent parasite-driven selection and mate preferences based on promotion of offspring heterozygosity at MHC, or potentially, genome-wide inbreeding avoidance. Where effects have been found, mate choice studies on rodents and other species usually find preference for MHC-dissimilarity in potential partners. Here we critically review studies on MHC-associated mate choice in humans. These are based on three broadly different aspects: (1) odor preferences, (2) facial preferences and (3) actual mate choice surveys. As in animal studies, most odor-based studies demonstrate disassortative preferences, although there is variation in the strength and nature of the effects. In contrast, facial attractiveness research indicates a preference for MHC-similar individuals. Results concerning MHC in actual couples show a bias towards similarity in one study, dissimilarity in two studies and random distribution in several other studies. These vary greatly in sample size and heterogeneity of the sample population, both of which may significantly bias the results. This pattern of mixed results across studies may reflect context-dependent and/or life history sensitive preference expression, in addition to higher level effects arising out of population differences in genetic heterogeneity or cultural and ethnic restrictions on random mating patterns. Factors of special relevance in terms of individual preferences are reproductive status and long- vs. short-term mating context. We discuss the idea that olfactory and visual channels may work in a complementary way (i.e. odor preference for MHC-dissimilarity and visual preference for MHC-similarity) to achieve an optimal level of genetic variability, methodological issues and interesting avenues for further research.

Results of oil flow visualization tests of an 0.010-scale model (52-OT) of the space shuttle orbiter-tank mated and orbiter configurations in the AEDC VKF tunnel B (IA17B)

NASA Technical Reports Server (NTRS)

Daileda, J. J.

1975-01-01

An 0.010-scale model of the space shuttle (orbiter-tank mated and orbiter configurations) was tested in the AEDC VKF Tunnel B to investigate aerodynamic flow patterns. The tests utilized oil flow techniques to visualize the flow patterns. Tunnel free stream Mach number was 7.95 and nominal unit Reynolds number was 3.7 million per foot. Model angle of attack was varied from -5 deg through 10 deg and angle of sideslip was 0 deg and 2 deg. Photographs of resulting oil flow patterns are presented.

Promiscuity resolves constraints on social mate choice imposed by population viscosity.

PubMed

While, Geoffrey M; Uller, Tobias; Bordogna, Genevieve; Wapstra, Erik

2014-02-01

Population viscosity can have major consequences for adaptive evolution, in particular for phenotypes involved in social interactions. For example, population viscosity increases the probability of mating with close kin, resulting in selection for mechanisms that circumvent the potential negative consequences of inbreeding. Female promiscuity is often suggested to be one such mechanism. However, whether avoidance of genetically similar partners is a major selective force shaping patterns of promiscuity remains poorly supported by empirical data. Here, we show (i) that fine-scale genetic structure constrains social mate choice in a pair-bonding lizard, resulting in individuals pairing with genetically similar individuals, (ii) that these constraints are circumvented by multiple mating with less related individuals and (iii) that this results in increased heterozygosity of offspring. Despite this, we did not detect any significant effects of heterozygosity on offspring or adult fitness or a strong relationship between pair relatedness and female multiple mating. We discuss these results within the context of incorporating the genetic context dependence of mating strategies into a holistic understanding of mating system evolution. © 2013 John Wiley & Sons Ltd.

Male mate choice influences female promiscuity in Soay sheep

PubMed Central

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

Male mate choice influences female promiscuity in Soay sheep.

PubMed

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.

Genetic evidence for polygynandry in the black-striped pipefish Syngnathus abaster: a microsatellite-based parentage analysis.

PubMed

Hübner, Kerstin; Gonzalez-Wanguemert, Mercedes; Diekmann, Onno E; Serrão, Ester A

2013-01-01

Sexual selection theory predicts that, in organisms with reversed sex roles, more polyandrous species exhibit higher levels of sexual dimorphism. In the family Syngnathidae (pipefish, seahorses, and seadragons), males provide all parental care by carrying developing embryos on their ventral surfaces, and females develop secondary sex characters. Syngnathids exhibit a variety of genetic mating patterns, making them an ideal group to test predictions of sexual selection theory. Here, we describe the mating system of the black-striped pipefish Syngnathus abaster, using 4 highly variable microsatellites to analyze parentage of 102 embryos. Results revealed that 1) both sexes mate multiple times over the course of a pregnancy (polygynandrous mating system), 2) eggs are spatially segregated by maternity within each brood pouch, and 3) larger females have higher mating success (Kolmogorov-Smirnov test; P < 0.05). Together with similar studies of other syngnathid species, our results support the hypothesis that the mating system is related to the intensity of sexual dimorphism.

Leaders are more attractive: birds with bigger yellow breast patches are followed by more group-mates in foraging groups.

PubMed

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.

General view of the Aft Rocket Motor mated with the ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of the Aft Rocket Motor mated with the External Tank Attach Ring and Aft Skirt Assembly in the process of being mounted onto the Mobile Launch Platform in the Vehicle Assembly Building at Kennedy Space Center. - Space Transportation System, Solid Rocket Boosters, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

General view of the Aft Rocket Motor mated with the ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of the Aft Rocket Motor mated with the External Tank Attach Ring and Aft Skirt Assembly being transported from the Rotation Processing and Surge Facility to the Vehicle Assembly Building at Kennedy Space Center. - Space Transportation System, Solid Rocket Boosters, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

SEXUAL SELECTION THROUGH FEMALE CHOICE IN LAWES' PAROTIA, A LEK-MATING BIRD OF PARADISE.

PubMed

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.

Pollen flow in fragmented landscapes maintains genetic diversity following stand-replacing disturbance in a neotropical pioneer tree, Vochysia ferruginea Mart.

PubMed

Davies, S J; Cavers, S; Finegan, B; White, A; Breed, M F; Lowe, A J

2015-08-01

In forests with gap disturbance regimes, pioneer tree regeneration is typically abundant following stand-replacing disturbances, whether natural or anthropogenic. Differences in pioneer tree density linked to disturbance regime can influence pollinator behaviour and impact on mating patterns and genetic diversity of pioneer populations. Such mating pattern shifts can manifest as higher selfing rates and lower pollen diversity in old growth forest populations. In secondary forest, where more closely related pollen donors occur, an increase in biparental inbreeding is a potential problem. Here, we investigate the consequences of secondary forest colonisation on the mating patterns and genetic diversity of open-pollinated progeny arrays for the long-lived, self-compatible pioneer tree, Vochysia ferruginea, at two Costa Rican sites. Five microsatellite loci were screened across adult and seed cohorts from old growth forest with lower density, secondary forest with higher density, and isolated individual trees in pasture. Progeny from both old growth and secondary forest contexts were predominantly outcrossed (tm=1.00) and experienced low levels of biparental inbreeding (tm-ts=0.00-0.04). In contrast to predictions, our results indicated that the mating patterns of V. ferruginea are relatively robust to density differences between old growth and secondary forest stands. In addition, we observed that pollen-mediated gene flow possibly maintained the genetic diversity of open-pollinated progeny arrays in stands of secondary forest adults. As part of a natural resource management strategy, we suggest that primary forest remnants should be prioritised for conservation to promote restoration of genetic diversity during forest regeneration.

Sex at the margins: parthenogenesis vs. facultative and obligate sex in a Neotropical ant.

PubMed

Kellner, K; Seal, J N; Heinze, J

2013-01-01

Geographic parthenogenesis is a distribution pattern, in which parthenogenetic populations tend to live in marginal habitats, at higher latitudes and altitudes and island-like habitats compared with the sexual forms. The facultatively parthenogenetic ant Platythyrea punctata is thought to exhibit this general pattern throughout its wide range in Central America and the Caribbean Islands. Workers of P. punctata from the Caribbean produce diploid female offspring from unfertilized eggs by thelytokous parthenogenesis, and mated females and males are rare. In contrast, workers in one colony from Costa Rica were incapable of thelytoky; instead mated workers produced all female offspring. Because sample sizes were very low in former studies, we here use microsatellite markers and explicit tests of thelytoky to examine the population genetic structure of ancestral and derived populations of P. punctata throughout the Caribbean and Central America. Populations from the Caribbean islands were fully capable of parthenogenesis, and population genetic signatures indicate that this is the predominant mode of reproduction, although males are occasionally produced. In contrast, the northernmost population on the mainland (Texas) showed signatures of sexual reproduction, and individuals were incapable of reproduction by thelytoky. Contrary to expectations from a geographic parthenogenesis distribution pattern, most parts of the mainland populations were found to be facultatively thelytokous, with population genetic signatures of both sexual and parthenogenetic reproduction. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Non-random pairing in American kestrels: mate choice versus intra-sexual competition

USGS Publications Warehouse

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.

An Alternative to Adaptation by Sexual Selection: Habitat Choice.

PubMed

Porter, Cody K; Akcali, Christopher K

2018-06-09

Adaptation in mating signals and preferences has generally been explained by sexual selection. We propose that adaptation in such mating traits might also arise via a non-mutually exclusive process wherein individuals preferentially disperse to habitats where they experience high mating performance. Here we explore the evolutionary implications of this process. Copyright © 2018 Elsevier Ltd. All rights reserved.

How does selfing affect the dynamics of selfish transposable elements?

PubMed

Boutin, Thibaud S; Le Rouzic, Arnaud; Capy, Pierre

2012-03-07

Many theoretical models predicting the dynamics of transposable elements (TEs) in genomes, populations, and species have already been proposed. However, most of them only focus on populations of sexual diploid individuals, and TE dynamics in populations partly composed by autogamous individuals remains poorly investigated. To estimate the impact of selfing on TE dynamics, the short- and long-term evolution of TEs was simulated in outcrossing populations with various proportions of selfing individuals. Selfing has a deep impact on TE dynamics: the higher the selfing rate, the lower the probability of invasion. Already known non-equilibrium dynamics (complete loss, domestication, cyclical invasion of TEs) can all be described whatever the mating system. However, their pattern and their respective frequencies greatly depend on the selfing rate. For instance, in cyclical dynamics resulting from interactions between autonomous and non-autonomous copies, cycles are faster when the selfing rate increases. Interestingly, an abrupt change in the mating system from sexuality to complete asexuality leads to the loss of all the elements over a few hundred generations. In general, for intermediate selfing rates, the transposition activity remains maintained. Our theoretical results evidence that a clear and systematic contrast in TE content according to the mating system is expected, with a smooth transition for intermediate selfing rates. Several parameters impact the TE copy number, and all dynamics described in allogamous populations can be also observed in partly autogamous species. This study thus provides new insights to understand the complex signal from empirical comparison of closely related species with different mating systems.

Male dominance rank and reproductive success in chimpanzees, Pan troglodytes schweinfurthii.

PubMed

Wroblewski, Emily E; Murray, Carson M; Keele, Brandon F; Schumacher-Stankey, Joann C; Hahn, Beatrice H; Pusey, Anne E

2009-01-01

Competition for fertile females determines male reproductive success in many species. The priority of access model predicts that male dominance rank determines access to females, but this model has been difficult to test in wild populations, particularly in promiscuous mating systems. Tests of the model have produced variable results, probably because of the differing socioecological circumstances of individual species and populations. We tested the predictions of the priority of access model in the chimpanzees of Gombe National Park, Tanzania. Chimpanzees are an interesting species in which to test the model because of their fission-fusion grouping patterns, promiscuous mating system and alternative male mating strategies. We determined paternity for 34 offspring over a 22-year period and found that the priority of access model was generally predictive of male reproductive success. However, we found that younger males had higher success per male than older males, and low-ranking males sired more offspring than predicted. Low-ranking males sired offspring with younger, less desirable females and by engaging in consortships more often than high-ranking fathers. Although alpha males never sired offspring with related females, inbreeding avoidance of high-ranking male relatives did not completely explain the success of low-ranking males. While our work confirms that male rank typically predicts male chimpanzee reproductive success, other factors are also important; mate choice and alternative male strategies can give low-ranking males access to females more often than would be predicted by the model. Furthermore, the success of younger males suggests that they are more successful in sperm competition.

Sex determination and gender expression: Reproductive investment in snails.

PubMed

Koene, Joris M

2017-02-01

Sex determination is generally seen as an issue of importance for separate-sexed organisms; however, when considering other sexual systems, such as hermaphroditism, sex allocation is a less-binary form of sex determination. As illustrated here, with examples from molluscs, this different vantage point can offer important evolutionary insights. After all, males and females produce only one type of gamete, whereas hermaphrodites produce both. In addition, sperm and accessory gland products are donated bidirectionally. For reciprocal mating, this is obvious since sperm are exchanged within one mating interaction; but even unilaterally mating species end up mating in both sexual roles, albeit not simultaneously. With this in mind, I highlight two factors that play an important role in how reproductive investment is divided in snails: First, the individual's motivation to preferentially donate rather than receive sperm (or vice versa) leads to flexible behavioral performance, and thereby investment, of either sex. Second, due to the presence of both sexual roles within the same individual, partners are potentially able to influence investment in both sexual functions of their partner to their own benefit. The latter has already led to novel insights into how accessory gland products may evolve. Moreover, the current evidence points towards different ways in which allocation to reproduction can be changed in simultaneous hermaphrodites. These often differ from the separate-sexed situation, highlighting that comparison across different sexual systems may help identify commonalities and differences in physiological, and molecular mechanisms as well as evolutionary patterns. Mol. Reprod. Dev. 84: 132-143, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Polyandry and sex-specific gene expression

PubMed Central

Mank, Judith E.; Wedell, Nina; Hosken, David J.

2013-01-01

Polyandry is widespread in nature, and has important evolutionary consequences for the evolution of sexual dimorphism and sexual conflict. Although many of the phenotypic consequences of polyandry have been elucidated, our understanding of the impacts of polyandry and mating systems on the genome is in its infancy. Polyandry can intensify selection on sexual characters and generate more intense sexual conflict. This has consequences for sequence evolution, but also for sex-biased gene expression, which acts as a link between mating systems, sex-specific selection and the evolution of sexual dimorphism. We discuss this and the remarkable confluence of sexual-conflict theory and patterns of gene expression, while also making predictions about transcription patterns, mating systems and sexual conflict. Gene expression is a key link in the genotype–phenotype chain, and although in its early stages, understanding the sexual selection–transcription relationship will provide significant insights into this critical association. PMID:23339238

Nest-mate recognition in Manuelia postica (Apidae: Xylocopinae): an eusocial trait is present in a solitary bee.

PubMed

Flores-Prado, Luis; Aguilera-Olivares, Daniel; Niemeyer, Hermann M

2008-02-07

In eusocial Hymenoptera, females are more tolerant towards nest-mate than towards non-nest-mate females. In solitary Hymenoptera, females are generally aggressive towards any conspecific female. Field observations of the nest biology of Manuelia postica suggested nest-mate recognition. Experiments were performed involving two live interacting females or one live female interacting with a dead female. Live females from different nests were more intolerant to each other than females from the same nest. Females were more intolerant towards non-nest-mate than towards nest-mate dead females. When dead females were washed with pentane, no differences in tolerant and intolerant behaviours were detected between non-nest-mate and nest-mate females. Females were more intolerant towards nest-mate female carcasses coated with the cuticular extract from a non-nest-mate than towards non-nest-mate female carcasses coated with the cuticular extract from a nest-mate. The compositions of the cuticular extracts was more similar between females from the same nest than between females from different nests. The results demonstrate for the first time nest-mate recognition mediated by cuticular chemicals in a largely solitary species of Apidae. The position of Manuelia at the base of the Apidae phylogeny suggests that nest-mate recognition in eusocial species apical to Manuelia represents the retention of a primitive capacity in Apidae.

Analysis of the Mediterranean fruit fly [Ceratitis capitata (Wiedemann)] spatio-temporal distribution in relation to sex and female mating status for precision IPM

PubMed Central

Tabilio, Maria Rosaria; Lampazzi, Elena; Ceccaroli, Claudio; Colacci, Marco; Trematerra, Pasquale

2018-01-01

The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), is a key pest of fruit crops in many tropical, subtropical and mild temperate areas worldwide. The economic importance of this fruit fly is increasing due to its invasion of new geographical areas. Efficient control and eradication efforts require adequate information regarding C. capitata adults in relation to environmental and physiological cues. This would allow effective characterisation of the population spatio-temporal dynamic of the C. capitata population at both the orchard level and the area-wide landscape. The aim of this study was to analyse population patterns of adult medflies caught using two trapping systems in a peach orchard located in central Italy. They were differentiated by adult sex (males or females) and mating status of females (unmated or mated females) to determine the spatio-temporal dynamic and evaluate the effect of cultivar and chemical treatments on trap catches. Female mating status was assessed by spermathecal dissection and a blind test was carried out to evaluate the reliability of the technique. Geostatistical methods, variogram and kriging, were used to produce distributional maps. Results showed a strong correlation between the distribution of males and unmated females, whereas males versus mated females and unmated females versus mated females showed a lower correlation. Both cultivar and chemical treatments had significant effects on trap catches, showing associations with sex and female mating status. Medfly adults showed aggregated distributions in the experimental field, but hot spots locations varied. The spatial pattern of unmated females reflected that of males, whereas mated females were largely distributed around ripening or ripe fruit. The results give relevant insights into pest management. Mated females may be distributed differently to unmated females and the identification of male hot spots through monitoring would allow localisation of virgin female populations. Based on our results, a more precise IPM strategy, coupled with effective sanitation practices, could represent a more effective approach to medfly control. PMID:29617420

Assortative mating without assortative preference

PubMed Central

Xie, Yu; Cheng, Siwei; Zhou, Xiang

2015-01-01

Assortative mating—marriage of a man and a woman with similar social characteristics—is a commonly observed phenomenon. In the existing literature in both sociology and economics, this phenomenon has mainly been attributed to individuals’ conscious preferences for assortative mating. In this paper, we show that patterns of assortative mating may arise from another structural source even if individuals do not have assortative preferences or possess complementary attributes: dynamic processes of marriages in a closed system. For a given cohort of youth in a finite population, as the percentage of married persons increases, unmarried persons who newly enter marriage are systematically different from those who married earlier, giving rise to the phenomenon of assortative mating. We use microsimulation methods to illustrate this dynamic process, using first the conventional deterministic Gale–Shapley model, then a probabilistic Gale–Shapley model, and then two versions of the encounter mating model. PMID:25918366

Optimal level of inbreeding in the common lizard.

PubMed

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.

Multivariate selection drives concordant patterns of pre- and postcopulatory sexual selection in a livebearing fish.

PubMed

Devigili, Alessandro; Evans, Jonathan P; Di Nisio, Andrea; Pilastro, Andrea

2015-09-15

In many species, females mate with multiple partners, meaning that sexual selection on male traits operates across a spectrum that encompasses the competition for mates (that is, before mating) and fertilizations (after mating). Despite being inextricably linked, pre- and postcopulatory sexual selection are typically studied independently, and we know almost nothing about how sexual selection operates across this divide. Here we bridge this knowledge gap using the livebearing fish Poecilia reticulata. We show that both selective episodes, as well as their covariance, explain a significant component of variance in male reproductive fitness. Moreover, linear and nonlinear selection simultaneously act on pre- and postcopulatory traits, and interact to generate multiple phenotypes with similar fitness.

Evaluation of the MoleMate training program for assessment of suspicious pigmented lesions in primary care.

PubMed

Wood, Annabel; Morris, Helen; Emery, Jon; Hall, Per N; Cotton, Symon; Prevost, A Toby; Walter, Fiona M

2008-01-01

Pigmented skin lesions or 'moles' are a common presenting problem in general practice consultations: while the majority are benign, a minority are malignant melanomas. The MoleMate system is a novel diagnostic tool which incorporates spectrophotometric intracutaneous analysis (SIAscopy) within a non-invasive scanning technique and utilises a diagnostic algorithm specifically developed for use in primary care. The MoleMate training program is a short, computer-based course developed to train primary care practitioners to operate the MoleMate diagnostic tool. This pre-trial study used mixed methods to assess the effectiveness and acceptability of a computer-based training program CD-ROM, developed to teach primary care practitioners to identify the seven features of suspicious pigmented lesions (SPLs) seen with the MoleMate system. Twenty-five practitioners worked through the MoleMate training program: data on feature recognition and time taken to conduct the assessment of each lesion were collected. Acceptability of the training program and the MoleMate system in general was assessed by questionnaire. The MoleMate training program improved users' feature recognition by 10% (pre-test median 73.8%, p<0.001), and reduced the time taken to complete assessment of 30 SPLs (pre-test median 21 minutes 53 seconds, median improvement 3 minutes 17 seconds, p<0.001). All practitioners' feature recognition improved (21/21), with most also improving their time (18/21). Practitioners rated the training program as effective and easy to use. The MoleMate training program is a potentially effective and acceptable informatics tool to teach practitioners to recognise the features of SPLs identified by the MoleMate system. It will be used as part of the intervention in a randomised controlled trial to compare the diagnostic accuracy and appropriate referral rates of practitioners using the MoleMate system with best practice in primary care.

Floral contrivances and specialised pollination mechanism strongly influence mixed mating in Wrightia tomentosa (Apocynaceae).

PubMed

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.

Mate-finding as an overlooked critical determinant of dispersal variation in sexually-reproducing animals.

PubMed

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.

Late Middle Paleolithic Adaptations and Their Possible Consequences

ERIC Educational Resources Information Center

Binford, Sally R.

1970-01-01

Correlates paleontological and archaeological data and proposes that evolutionary changes in the "Progressive Neanderthals resulted from changes in hunting patterns with accompanying changes in tool manufacture, social grouping, and mating patterns. (EB)

Personality differentially affects individual mate choice decisions in female and male Western mosquitofish (Gambusia affinis).

PubMed

Chen, Bo-Jian; Liu, Kai; Zhou, Lin-Jun; Gomes-Silva, Guilherme; Sommer-Trembo, Carolin; Plath, Martin

2018-01-01

Consistent individual differences in behavioral tendencies (animal personality) can affect individual mate choice decisions. We asked whether personality traits affect male and female mate choice decisions similarly and whether potential personality effects are consistent across different mate choice situations. Using western mosquitofish (Gambusia affinis) as our study organism, we characterized focal individuals (males and females) twice for boldness, activity, and sociability/shoaling and found high and significant behavioral repeatability. Additionally, each focal individual was tested in two different dichotomous mate choice tests in which it could choose between computer-animated stimulus fish of the opposite sex that differed in body size and activity levels, respectively. Personality had different effects on female and male mate choice: females that were larger than average showed stronger preferences for large-bodied males with increasing levels of boldness/activity (i.e., towards more proactive personality types). Males that were larger than average and had higher shoaling tendencies showed stronger preferences for actively swimming females. Size-dependent effects of personality on the strength of preferences for distinct phenotypes of potential mating partners may reflect effects of age/experience (especially in females) and social dominance (especially in males). Previous studies found evidence for assortative mate choice based on personality types or hypothesized the existence of behavioral syndromes of individuals' choosiness across mate choice criteria, possibly including other personality traits. Our present study exemplifies that far more complex patterns of personality-dependent mate choice can emerge in natural systems.

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.

MHC-disassortative mate choice and inbreeding avoidance in a solitary primate.

PubMed

Huchard, Elise; Baniel, Alice; Schliehe-Diecks, Susanne; Kappeler, Peter M

2013-08-01

Sexual selection theory suggests that choice for partners carrying dissimilar genes at the major histocompatibility complex (MHC) may play a role in maintaining genetic variation in animal populations by limiting inbreeding or improving the immunity of future offspring. However, it is often difficult to establish whether the observed MHC dissimilarity among mates drives mate choice or represents a by-product of inbreeding avoidance based on MHC-independent cues. Here, we used 454-sequencing and a 10-year study of wild grey mouse lemurs (Microcebus murinus), small, solitary primates from western Madagascar, to compare the relative importance on the mate choice of two MHC class II genes, DRB and DQB, that are equally variable but display contrasting patterns of selection at the molecular level, with DRB under stronger diversifying selection. We further assessed the effect of the genetic relatedness and of the spatial distance among candidate mates on the detection of MHC-dependent mate choice. Our results reveal inbreeding avoidance, along with disassortative mate choice at DRB, but not at DQB. DRB-disassortative mate choice remains detectable after excluding all related dyads (characterized by a relatedness coefficient r > 0), but varies slightly with the spatial distance among candidate mates. These findings suggest that the observed deviations from random mate choice at MHC are driven by functionally important MHC genes (like DRB) rather than passively resulting from inbreeding avoidance and further emphasize the need for taking into account the spatial and genetic structure of the population in correlative tests of MHC-dependent mate choice. © 2013 John Wiley & Sons Ltd.

Balancing in- and out-breeding by the predatory mite Phytoseiulus persimilis.

PubMed

Atalay, Demet; Schausberger, Peter

2018-02-01

In- and out-breeding depressions are commonly observed phenomena in sexually reproducing organisms with a patchy distribution pattern, and spatial segmentation and/or isolation of groups. At the genetic level, inbreeding depression is due to increased homozygosity, whereas outbreeding depression is due to inferior genetic compatibility of mates. Optimal outbreeding theory suggests that intermediate levels of mate relatedness should provide for the highest fitness gains. Here, we assessed the fitness consequences of genetic relatedness between mates in plant-inhabiting predatory mites Phytoseiulus persimilis, which are obligatory sexually reproducing but haplo-diploid. Both females and males arise from fertilized eggs but males lose the paternal chromosome set during embryogenesis, dubbed pseudo-arrhenotoky. Phytoseiulus persimilis are highly efficacious in reducing crop-damaging spider mite populations and widely used in biological control. Using iso-female lines of two populations, from Sicily and Greece, we assessed the fecundity of females, and sex ratio of their offspring, that mated with either a sibling, a male from the same population or a male from the other population. Additionally, we recorded mating latency and duration. Females mating with a male from the same population produced more eggs, with a lower female bias, over a longer time than females mating with a sibling or with a male from the other population. Mating latency was unaffected by mate relatedness; mating duration was disproportionally long in sibling couples, likely indicating female reluctance to mate and sub-optimal spermatophore transfer. Our study provides a rare example of in- and out-breeding depression in a haplo-diploid arthropod, supporting the optimal outbreeding theory.

Mating patterns in a savanna population of valley oak (Quercus labata Neé)

Treesearch

Victoria L. Sork; Frank W. Davis; Rodney J. Dyer; Peter E. Smouse

2002-01-01

California valley oak is threatened by landscape alteration and failing recruitment in remnant stands. Its reproductive ecology is a key element of the seedling recruitment process. We first examine the mating system, to determine the extent of inbreeding in a population at Sedgwick Reserve, in Santa Barbara County. We then quantify variation in germination success and...

Paced mating behavior is affected by clitoral-vaginocervical lidocaine application in combination with sexual experience.

PubMed

Meerts, Sarah H; Strnad, Helen K; Schairer, Rosemary S

2015-03-01

The present study tested the effects of lidocaine anesthetic ointment applied to the vaginocervical (Experiment 1) or clitoral-vaginocervical (Experiment 2) areas on the display of paced mating behavior over the course of five weekly tests in ovariectomized, hormone-primed, Long-Evans rats. Experiment 3 tested whether rats that acquired sexual experience without ointment application would exhibit altered paced mating behavior on a fifth test under clitoral-vaginocervical lidocaine or vehicle application. Although rats in Experiment 1 and Experiment 2 exhibited shorter contact-return latencies after intromission and reduced likelihood of leaving the male compartment following mounts and intromissions after gaining sexual experience, only rats that received clitoral-vaginocervical lidocaine exhibited altered paced mating behavior relative to vehicle. Specifically, clitoral-vaginocervical lidocaine resulted in shorter contact-return latency to ejaculation and greater percentage of time with the male. Paced mating behavior of sexually experienced rats in Experiment 3 was not disrupted when tested after clitoral-vaginocervical lidocaine treatment. Together, these studies suggest that the sensory input during repeated mating encounters affects the pattern of paced mating behavior that develops with sexual experience. Copyright © 2014 Elsevier Inc. All rights reserved.

Patterns of pair formation and mating in an ectoparasitic caligid copepod Lepeophtheirus salmonis (Krøyer 1837): implications for its sensory and mating biology

PubMed Central

Hull, M. Q.

1998-01-01

Non-invasive observations of single cohort and manipulated populations of the sealouse on laboratory-maintained salmon established the sequence of reproductive events and mating. Protandry occurs with adult male emergence synchronized with pre-adult II female emergence, the stage at which most pair formation and pre-copular guarding takes place. Male competence for pair formation and mating was achieved within 24 h of the final moult and pairing occurred according to the preference hierarchy, virgin adult females greater than pre-adult II females much greater than pre-adult I females. This hierarchy broke down when the adult male to unmated female ratio increased rapidly. Males mated successfully not only with newly moulted adult females, but also with older virgin females in which enlargement of the genital complex and premature extrusion of egg strings had occurred. Multiple mating by adult males was demonstrated and may be widespread. Significant inter-host transfer was also demonstrated. Adult males were more mobile than adult females and showed significantly more inter-host transfer. Ablation of the distal tip of the antennules significantly reduced the success of host-finding, pair formation and males' mating.

Social Mating System and Sex-Biased Dispersal in Mammals and Birds: A Phylogenetic Analysis

PubMed Central

Mabry, Karen E.; Shelley, Erin L.; Davis, Katie E.; Blumstein, Daniel T.; Van Vuren, Dirk H.

2013-01-01

The hypothesis that patterns of sex-biased dispersal are related to social mating system in mammals and birds has gained widespread acceptance over the past 30 years. However, two major complications have obscured the relationship between these two behaviors: 1) dispersal frequency and dispersal distance, which measure different aspects of the dispersal process, have often been confounded, and 2) the relationship between mating system and sex-biased dispersal in these vertebrate groups has not been examined using modern phylogenetic comparative methods. Here, we present a phylogenetic analysis of the relationship between mating system and sex-biased dispersal in mammals and birds. Results indicate that the evolution of female-biased dispersal in mammals may be more likely on monogamous branches of the phylogeny, and that females may disperse farther than males in socially monogamous mammalian species. However, we found no support for a relationship between social mating system and sex-biased dispersal in birds when the effects of phylogeny are taken into consideration. We caution that although there are larger-scale behavioral differences in mating system and sex-biased dispersal between mammals and birds, mating system and sex-biased dispersal are far from perfectly associated within these taxa. PMID:23483957

Molecular cloning and functional characterization of DkMATE1 involved in proanthocyanidin precursor transport in persimmon (Diospyros kaki Thunb.) fruit.

PubMed

Yang, Sichao; Jiang, Yun; Xu, Liqing; Shiratake, Katsuhiro; Luo, Zhengrong; Zhang, Qinglin

2016-11-01

Persimmon fruits accumulate a large amount of proanthocyanidins (PAs) in "tannin cells" during development that cause the sensation of astringency due to coagulation of oral proteins. Pollination-constant non-astringent (PCNA) is a spontaneous mutant persimmon phenotype that loses its astringency naturally on the tree at maturity; while the more common non-PCNA fruits remain rich in PAs until they are fully ripened. Here, we isolated a DkMATE1 gene encoding a Multidrug And Toxic Compound Extrusion (MATE) family protein from the Chinese PCNA (C-PCNA) 'Eshi 1'. Expression patterns of DkMATE1 were positively correlated with the accumulation of PAs in different types of persimmons fruits during fruit development. An analysis of the inferred amino acid sequences and phylogenetic relationships indicated that DkMATE1 is a putative PA precursor transporter, and subcellular localization assays revealed that DkMATE1 is localized in the vacuolar membrane. Ectopic expression of the DkMATE1 in Arabidopsis tt12 mutant supported that DkMATE1 could complement its biological function in transporting epicatechin 3'-O-glucoside as a PAs precursor from the cytoplasm to vacuole. Furthermore, the transient over-expression and silencing of DkMATE1 in 'Mopanshi' persimmon leaves resulted in a significant increase and a decrease in PA content, respectively. The analysis of cis-elements in DkMATE1 promoter regions indicated that DkMATE1 might be regulated by DkMYB4, another well-known structural gene in persimmon. Overall, our results show that DkMATE1 may be an essential PA precursor membrane transporter that plays an important role in PA biosynthesis in persimmon. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Optimal numbers of matings: the conditional balance between benefits and costs of mating for females of a nuptial gift-giving spider.

PubMed

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.

Competition between larvae in a butterfly Pieris napi and maintenance of different life-history strategies.

PubMed

Kivelä, Sami M; Välimäki, Panu

2008-05-01

1. In scramble competition all individuals suffer equally from competition, whereas in contest competition some individuals outperform the others. Generally, larger individuals gain asymmetric advantage in competition over smaller ones. Given the positive correlation between age and size, asynchronous birth may result in asymmetric competition among juveniles. 2. In Pieris napi (Lepidoptera: Pieridae), reproductive rate is determined by the females' intrinsic mating tactic. The early reproductive rate is high in females with a low mating frequency and low in females with a high mating frequency, whereas lifetime fecundity shows the opposite pattern. Thus, offspring of monandrous females start to develop in relatively low densities and they are relatively large when the offspring of highly polyandrous females start to hatch. 3. The purpose of this study was to explore if asymmetry in larval competition could outweigh the late-life benefits of polyandry. In a laboratory experiment, P. napi larvae of different ages were reared together in different densities. 4. Increasing density decreased both larval survival and reachable pupal mass, but had no effect on duration of larval period. Younger larvae suffered from high mortality and reduced size compared with the older larvae. Mortality decreased in the older cohort with increasing age difference between the cohorts, and the reverse occurred in the younger cohort. Increasing age difference between the cohorts was associated with increase in pupal mass in both cohorts. All the variables showed a lot of variation between broods of different females. 5. The results suggest that polyandrous females, or more generally females with a low early reproductive rate, may lose a great proportion of their late-life benefits, which may partly explain the maintenance of polymorphism in reproductive strategies within species.

Assortative Mating for Emotional Intelligence.

PubMed

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.

Density-dependent natal dispersal patterns in a leopard population recovering from over-harvest.

PubMed

Fattebert, Julien; Balme, Guy; Dickerson, Tristan; Slotow, Rob; Hunter, Luke

2015-01-01

Natal dispersal enables population connectivity, gene flow and metapopulation dynamics. In polygynous mammals, dispersal is typically male-biased. Classically, the 'mate competition', 'resource competition' and 'resident fitness' hypotheses predict density-dependent dispersal patterns, while the 'inbreeding avoidance' hypothesis posits density-independent dispersal. In a leopard (Panthera pardus) population recovering from over-harvest, we investigated the effect of sex, population density and prey biomass, on age of natal dispersal, distance dispersed, probability of emigration and dispersal success. Over an 11-year period, we tracked 35 subadult leopards using VHF and GPS telemetry. Subadult leopards initiated dispersal at 13.6 ± 0.4 months. Age at commencement of dispersal was positively density-dependent. Although males (11.0 ± 2.5 km) generally dispersed further than females (2.7 ± 0.4 km), some males exhibited opportunistic philopatry when the population was below capacity. All 13 females were philopatric, while 12 of 22 males emigrated. Male dispersal distance and emigration probability followed a quadratic relationship with population density, whereas female dispersal distance was inversely density-dependent. Eight of 12 known-fate females and 5 of 12 known-fate male leopards were successful in settling. Dispersal success did not vary with population density, prey biomass, and for males, neither between dispersal strategies (philopatry vs. emigration). Females formed matrilineal kin clusters, supporting the resident fitness hypothesis. Conversely, mate competition appeared the main driver for male leopard dispersal. We demonstrate that dispersal patterns changed over time, i.e. as the leopard population density increased. We conclude that conservation interventions that facilitated local demographic recovery in the study area also restored dispersal patterns disrupted by unsustainable harvesting, and that this indirectly improved connectivity among leopard populations over a larger landscape.

Spatial genetic structure in Beta vulgaris subsp. maritima and Beta macrocarpa reveals the effect of contrasting mating system, influence of marine currents, and footprints of postglacial recolonization routes.

PubMed

Leys, Marie; Petit, Eric J; El-Bahloul, Yasmina; Liso, Camille; Fournet, Sylvain; Arnaud, Jean-François

2014-05-01

Understanding the factors that contribute to population genetic divergence across a species' range is a long-standing goal in evolutionary biology and ecological genetics. We examined the relative importance of historical and ecological features in shaping the present-day spatial patterns of genetic structure in two related plant species, Beta vulgaris subsp. maritima and Beta macrocarpa. Using nuclear and mitochondrial markers, we surveyed 93 populations from Brittany (France) to Morocco - the southern limit of their species' range distribution. Whereas B. macrocarpa showed a genotypic structure and a high level of genetic differentiation indicative of selfing, the population genetic structure of B. vulgaris subsp. maritima was consistent with an outcrossing mating system. We further showed (1) a strong geographic clustering in coastal B. vulgaris subsp. maritima populations that highlighted the influence of marine currents in shaping different lineages and (2) a peculiar genetic structure of inland B. vulgaris subsp. maritima populations that could indicate the admixture of distinct evolutionary lineages and recent expansions associated with anthropogenic disturbances. Spatial patterns of nuclear diversity and differentiation also supported a stepwise recolonization of Europe from Atlantic-Mediterranean refugia after the last glacial period, with leading-edge expansions. However, cytoplasmic diversity was not impacted by postglacial recolonization: stochastic long-distance seed dispersal mediated by major oceanic currents may mitigate the common patterns of reduced cytoplasmic diversity observed for edge populations. Overall, the patterns we documented here challenge the general view of reduced genetic diversity at the edge of a species' range distribution and provide clues for understanding how life-history and major geographic features interact to shape the distribution of genetic diversity.

Spatial genetic structure in Beta vulgaris subsp. maritima and Beta macrocarpa reveals the effect of contrasting mating system, influence of marine currents, and footprints of postglacial recolonization routes

PubMed Central

Leys, Marie; Petit, Eric J; El-Bahloul, Yasmina; Liso, Camille; Fournet, Sylvain; Arnaud, Jean-François

2014-01-01

Understanding the factors that contribute to population genetic divergence across a species' range is a long-standing goal in evolutionary biology and ecological genetics. We examined the relative importance of historical and ecological features in shaping the present-day spatial patterns of genetic structure in two related plant species, Beta vulgaris subsp. maritima and Beta macrocarpa. Using nuclear and mitochondrial markers, we surveyed 93 populations from Brittany (France) to Morocco – the southern limit of their species' range distribution. Whereas B. macrocarpa showed a genotypic structure and a high level of genetic differentiation indicative of selfing, the population genetic structure of B. vulgaris subsp. maritima was consistent with an outcrossing mating system. We further showed (1) a strong geographic clustering in coastal B. vulgaris subsp. maritima populations that highlighted the influence of marine currents in shaping different lineages and (2) a peculiar genetic structure of inland B. vulgaris subsp. maritima populations that could indicate the admixture of distinct evolutionary lineages and recent expansions associated with anthropogenic disturbances. Spatial patterns of nuclear diversity and differentiation also supported a stepwise recolonization of Europe from Atlantic-Mediterranean refugia after the last glacial period, with leading-edge expansions. However, cytoplasmic diversity was not impacted by postglacial recolonization: stochastic long-distance seed dispersal mediated by major oceanic currents may mitigate the common patterns of reduced cytoplasmic diversity observed for edge populations. Overall, the patterns we documented here challenge the general view of reduced genetic diversity at the edge of a species' range distribution and provide clues for understanding how life-history and major geographic features interact to shape the distribution of genetic diversity. PMID:24963380

Density-Dependent Natal Dispersal Patterns in a Leopard Population Recovering from Over-Harvest

PubMed Central

Fattebert, Julien; Balme, Guy; Dickerson, Tristan; Slotow, Rob; Hunter, Luke

2015-01-01

Natal dispersal enables population connectivity, gene flow and metapopulation dynamics. In polygynous mammals, dispersal is typically male-biased. Classically, the ‘mate competition’, ‘resource competition’ and ‘resident fitness’ hypotheses predict density-dependent dispersal patterns, while the ‘inbreeding avoidance’ hypothesis posits density-independent dispersal. In a leopard (Panthera pardus) population recovering from over-harvest, we investigated the effect of sex, population density and prey biomass, on age of natal dispersal, distance dispersed, probability of emigration and dispersal success. Over an 11-year period, we tracked 35 subadult leopards using VHF and GPS telemetry. Subadult leopards initiated dispersal at 13.6 ± 0.4 months. Age at commencement of dispersal was positively density-dependent. Although males (11.0 ± 2.5 km) generally dispersed further than females (2.7 ± 0.4 km), some males exhibited opportunistic philopatry when the population was below capacity. All 13 females were philopatric, while 12 of 22 males emigrated. Male dispersal distance and emigration probability followed a quadratic relationship with population density, whereas female dispersal distance was inversely density-dependent. Eight of 12 known-fate females and 5 of 12 known-fate male leopards were successful in settling. Dispersal success did not vary with population density, prey biomass, and for males, neither between dispersal strategies (philopatry vs. emigration). Females formed matrilineal kin clusters, supporting the resident fitness hypothesis. Conversely, mate competition appeared the main driver for male leopard dispersal. We demonstrate that dispersal patterns changed over time, i.e. as the leopard population density increased. We conclude that conservation interventions that facilitated local demographic recovery in the study area also restored dispersal patterns disrupted by unsustainable harvesting, and that this indirectly improved connectivity among leopard populations over a larger landscape. PMID:25875293

General view of the Aft Skirt Assembly and the Aft ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of the Aft Skirt Assembly and the Aft Solid Rocket Motor Segment mated together in the Vehicle Assembly Building at Kennedy Space Center and being prepared for mounting onto the Mobile Launch Platform and mating with the other Solid Rocket Booster segments. - Space Transportation System, Solid Rocket Boosters, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Sex and Caste-Specific Variation in Compound Eye Morphology of Five Honeybee Species

PubMed Central

Streinzer, Martin; Brockmann, Axel; Nagaraja, Narayanappa; Spaethe, Johannes

2013-01-01

Ranging from dwarfs to giants, the species of honeybees show remarkable differences in body size that have placed evolutionary constrains on the size of sensory organs and the brain. Colonies comprise three adult phenotypes, drones and two female castes, the reproductive queen and sterile workers. The phenotypes differ with respect to tasks and thus selection pressures which additionally constrain the shape of sensory systems. In a first step to explore the variability and interaction between species size-limitations and sex and caste-specific selection pressures in sensory and neural structures in honeybees, we compared eye size, ommatidia number and distribution of facet lens diameters in drones, queens and workers of five species (Apis andreniformis, A. florea, A. dorsata, A. mellifera, A. cerana). In these species, male and female eyes show a consistent sex-specific organization with respect to eye size and regional specialization of facet diameters. Drones possess distinctly enlarged eyes with large dorsal facets. Aside from these general patterns, we found signs of unique adaptations in eyes of A. florea and A. dorsata drones. In both species, drone eyes are disproportionately enlarged. In A. dorsata the increased eye size results from enlarged facets, a likely adaptation to crepuscular mating flights. In contrast, the relative enlargement of A. florea drone eyes results from an increase in ommatidia number, suggesting strong selection for high spatial resolution. Comparison of eye morphology and published mating flight times indicates a correlation between overall light sensitivity and species-specific mating flight times. The correlation suggests an important role of ambient light intensities in the regulation of species-specific mating flight times and the evolution of the visual system. Our study further deepens insights into visual adaptations within the genus Apis and opens up future perspectives for research to better understand the timing mechanisms and sensory physiology of mating related signals. PMID:23460896

Dim artificial light at night affects mating, reproductive output, and reactive oxygen species in Drosophila melanogaster.

PubMed

McLay, Lucy Katherine; Nagarajan-Radha, Venkatesh; Green, Mark Philip; Jones, Therésa Melanie

2018-05-07

Humans are lighting the night-time environment with ever increasing extent and intensity, resulting in a variety of negative ecological effects in individuals and populations. Effects of light at night on reproductive fitness traits are demonstrated across taxa however, the mechanisms underlying these effects are largely untested. One possible mechanism is that light at night may result in perturbed reactive oxygen species (ROS) and oxidative stress levels. Here, we reared Drosophila melanogaster under either dim (10 lx) light or no light (0 lx) at night for three generations and then compared mating and lifetime oviposition patterns. In a second experiment, we explored whether exposure to light at night treatments resulted in variation in ROS levels in the heads and ovaries of six, 23- and 36-day-old females. We demonstrate that dim light at night affects mating and reproductive output: 10 lx flies courted for longer prior to mating, and female oviposition patterns differed to 0 lx females. ROS levels were lower in the ovaries but not heads, of 10 lx compared with 0 lx females. We suggest that reduced ROS levels may reflect changes in ovarian physiology and cell signaling, which may be related to the differences observed in oviposition patterns. Taken together, our results indicate negative consequences for invertebrates under more stressful, urban, lit conditions and further investigation into the mechanisms driving these changes is warranted to manage invertebrate communities in a brighter future. © 2018 Wiley Periodicals, Inc.

Reproductive behavior in the squid Sepioteuthis australis from South Australia: interactions on the spawning grounds.

PubMed

Jantzen, Troy M; Havenhand, Jon N

2003-06-01

Squid behavior is synonymous with distinctive body patterns, postures, and movements that constitute a complex visual communication system. These communications are particularly obvious during reproduction. They are important for sexual selection and have been identified as a potential means of species differentiation. Here we present a detailed account of copulation, mating, and egg deposition behaviors from in situ observations of the squid Sepioteuthis australis from South Australia. We identified four mating types from 85 separate mating attempts: "Male-upturned mating" (64% of mating attempts); "Sneaker mating" (33%); "Male-parallel" (2%); and "Head-to-head" (1%). Intervals between successive egg deposition behaviors were clearly bimodal, with modes at 2.5 s and 70.0 s. Ninety-three percent of egg capsules contained 3 or 4 eggs (mean = 3.54), and each egg cluster contained between 218 and 1922 egg capsules (mean = 893.9). The reproductive behavior of S. australis from South Australia was different from that described for other cephalopod species. More importantly, comparison between these results and those for other populations of S. australis suggests that behavior may differ from one population to another.

Mate choice trade-offs and women's preference for physically attractive men.

PubMed

Waynforth, D

2001-09-01

Researchers studying human sexuality have repeatedly concluded that men place more emphasis on the physical attractiveness of potential mates than women do, particularly in long-term sexual relationships. Evolutionary theorists have suggested that this is the case because male mate value (the total value of the characteristics that an individual possesses in terms of the potential contribution to his or her mate's reproductive success) is better predicted by social status and economic resources, whereas women's mate value hinges on signals conveyed by their physical appearance. This pattern may imply that women trade off attractiveness for resources in mate choice. Here I test whether a trade-off between resources and attractiveness seems to be occurring in the mate choice decisions of women in the United States. In addition, the possibility that the risk of mate desertion drives women to choose less attractive men as long-term mates is tested. The results were that women rated physically attractive men as more likely to cheat or desert a long-term relationship, whereas men did not consider attractive women to be more likely to cheat. However, women showed no aversion to the idea of forming long-term relationships with attractive men. Evidence for a trade-off between resources and attractiveness was found for women, who traded off attractiveness, but not other traits, for resources. The potential meaning of these findings, as well as how they relate to broader issues in the study of sex differences in the evolution of human mate choice for physical traits, is discussed.

Assortative mating for human height: A meta‐analysis

PubMed Central

Simons, Mirre J.P.; Grasman, Sara; Pollet, Thomas V.

2016-01-01

Abstract Objectives The study of assortative mating for height has a rich history in human biology. Although the positive correlation between the stature of spouses has often been noted in western populations, recent papers suggest that mating patterns for stature are not universal. The objective of this paper was to review the published evidence to examine the strength of and universality in assortative mating for height. Methods We conducted an extensive literature review and meta‐analysis. We started with published reviews but also searched through secondary databases. Our search led to 154 correlations of height between partners. We classified the populations as western and non‐western based on geography. These correlations were then analyzed via meta‐analytic techniques. Results 148 of the correlations for partner heights were positive and the overall analysis indicates moderate positive assortative mating (r = .23). Although assortative mating was slightly stronger in countries that can be described as western compared to non‐western, this difference was not statistically significant. We found no evidence for a change in assortative mating for height over time. There was substantial residual heterogeneity in effect sizes and this heterogeneity was most pronounced in western countries. Conclusions Positive assortative mating for height exists in human populations, but is modest in magnitude suggesting that height is not a major factor in mate choice. Future research is necessary to understand the underlying causes of the large amount of heterogeneity observed in the degree of assortative mating across human populations, which may stem from a combination of methodological and ecological differences. PMID:27637175

Synergistic selection between ecological niche and mate preference primes diversification.

PubMed

Boughman, Janette W; Svanbäck, Richard

2017-01-01

The ecological niche and mate preferences have independently been shown to be important for the process of speciation. Here, we articulate a novel mechanism by which ecological niche use and mate preference can be linked to promote speciation. The degree to which individual niches are narrow and clustered affects the strength of divergent natural selection and population splitting. Similarly, the degree to which individual mate preferences are narrow and clustered affects the strength of divergent sexual selection and assortative mating between diverging forms. This novel perspective is inspired by the literature on ecological niches; it also explores mate preferences and how they may contribute to speciation. Unlike much comparative work, we do not search for evolutionary patterns using proxies for adaptation and sexual selection, but rather we elucidate how ideas from niche theory relate to mate preference, and how this relationship can foster speciation. Recognizing that individual and population niches are conceptually and ecologically linked to individual and population mate preference functions will significantly increase our understanding of rapid evolutionary diversification in nature. It has potential to help solve the difficult challenge of testing the role of sexual selection in the speciation process. We also identify ecological factors that are likely to affect individual niche and individual mate preference in synergistic ways and as a consequence to promote speciation. The ecological niche an individual occupies can directly affect its mate preference. Clusters of individuals with narrow, differentiated niches are likely to have narrow, differentiated mate preference functions. Our approach integrates ecological and sexual selection research to further our understanding of diversification processes. Such integration may be necessary for progress because these processes seem inextricably linked in the natural world. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

General view of the Aft Solid Rocket Motor Segment mated ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of the Aft Solid Rocket Motor Segment mated with the Aft Skirt Assembly and External Tank Attach Ring in the Rotation Processing and Surge Facility at Kennedy Space Center and awaiting transfer to the Vehicle Assembly Building where it will be mounted onto the Mobile Launch Platform. - Space Transportation System, Solid Rocket Boosters, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

When not to avoid inbreeding.

PubMed

Kokko, Hanna; Ots, Indrek

2006-03-01

Avoidance of incestuous matings is widely reported across many animal taxa, and the adaptive value of such behavior is explained through inbreeding depression. However, an old and somewhat neglected theoretical result predicts that inbred matings offer another, positive effect on the inclusive fitness of parents: an individual who mates with a relative will help that relative to spread genes identical by descent. This benefit can be substantial, if the additional mating achieved by the relative does not harm his mating success otherwise, and in the context of selfing in plants the phenomenon is well known. Here, we develop a model that derives expected values of inbreeding tolerance, that is, the magnitude of inbreeding depression that is required to make individuals avoid inbreeding, for different animal life histories and parental investment patterns. We also distinguish between simultaneous and sequential mate choice, and show that inbreeding tolerance should often be remarkably high in the latter scenario in particular, although egalitarian parental care will lead to lower tolerance. There is a mismatch between theory and data: the almost complete lack of cases where individuals prefer to mate incestuously is at odds with a large overlap between the predicted range of inbreeding tolerance and estimates of inbreeding depression found in nature. We discuss four different solutions to this enigma, and suggest that inbreeding tolerance, where it is found, should not always be attributed to a simple constraint that has prevented finding any other mate.

The mitonuclear compatibility hypothesis of sexual selection

PubMed Central

Hill, Geoffrey E.; Johnson, James D.

2013-01-01

Why females assess ornaments when choosing mates remains a central question in evolutionary biology. We hypothesize that the imperative for a choosing female to find a mate with nuclear oxidative phosphorylation (OXPHOS) genes that are compatible with her mitochondrial OXPHOS genes drives the evolution of ornaments. Indicator traits are proposed to signal the efficiency of OXPHOS function thus enabling females to select mates with nuclear genes that are compatible with maternal mitochondrial genes in the formation of OXPHOS complexes. Species-typical pattern of ornamentation is proposed to serve as a marker of mitochondrial type ensuring that females assess prospective mates with a shared mitochondrial background. The mitonuclear compatibility hypothesis predicts that the production of ornaments will be closely linked to OXPHOS pathways, and that sexual selection for compatible mates will be strongest when genes for nuclear components of OXPHOS complexes are Z-linked. The implications of this hypothesis are that sexual selection may serve as a driver for the evolution of more efficient cellular respiration. PMID:23945683

Assortative mating among animals of captive and wild origin following experimental conservation releases

PubMed Central

Slade, Brendan; Parrott, Marissa L.; Paproth, Aleisha; Magrath, Michael J. L.; Gillespie, Graeme R.; Jessop, Tim S.

2014-01-01

Captive breeding is a high profile management tool used for conserving threatened species. However, the inevitable consequence of generations in captivity is broad scale and often-rapid phenotypic divergence between captive and wild individuals, through environmental differences and genetic processes. Although poorly understood, mate choice preference is one of the changes that may occur in captivity that could have important implications for the reintroduction success of captive-bred animals. We bred wild-caught house mice for three generations to examine mating patterns and reproductive outcomes when these animals were simultaneously released into multiple outdoor enclosures with wild conspecifics. At release, there were significant differences in phenotypic (e.g. body mass) and genetic measures (e.g. Gst and F) between captive-bred and wild adult mice. Furthermore, 83% of offspring produced post-release were of same source parentage, inferring pronounced assortative mating. Our findings suggest that captive breeding may affect mating preferences, with potentially adverse implications for the success of threatened species reintroduction programmes. PMID:25411380

Optimal level of inbreeding in the common lizard

PubMed Central

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

Phenotypic plasticity in female mate choice behavior is mediated by an interaction of direct and indirect genetic effects in Drosophila melanogaster.

PubMed

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.

Sexual conflicts in spotted hyenas: male and female mating tactics and their reproductive outcome with respect to age, social status and tenure.

PubMed Central

East, Marion L; Burke, Terry; Wilhelm, Kerstin; Greig, Carolyn; Hofer, Heribert

2003-01-01

We investigated the reproductive outcomes of male and female mating tactics in the spotted hyena, Crocuta crocuta, a female-dominated social carnivore with high maternal investment, an absence of paternal care and female control over copulation. Paternity was determined using microsatellite profiling of 236 offspring in 171 litters from three clans. We found little evidence that male tactics that sought to coerce or monopolize females were successful. Polyandry and sperm competition appeared to counter effectively pre-copulatory male tactics, such as harassment, monopolization and other tactics, such as infanticide, that were against the evolutionary interests of females, and may have contributed to the stability of the male dominance hierarchy, which operated as a social queue. At least 39% of 54 females mated multiply, and 35% of 75 twin litters were fathered by two sires. Polyandry may also serve to ensure fertilization, compensate for an initial poor-quality mate or ensure fertilization by genetically compatible mates. Female mate choice matched observed patterns of affiliative male-female behaviour, indicating that affiliative behaviour is a successful male mating tactic, and was consistent with the idea that male tenure may serve as an index of male quality, although male fertility may decline with extreme old age. PMID:12816637

Mate choice and human stature: homogamy as a unified framework for understanding mating preferences.

PubMed

Courtiol, Alexandre; Raymond, Michel; Godelle, Bernard; Ferdy, Jean-Baptiste

2010-08-01

Assortative mating for human height has long attracted interest in evolutionary biology, and the phenomenon has been demonstrated in numerous human populations. It is often argued that mating preferences generate this pattern, but other processes can also induce trait correlations between mates. Here, we present a methodology tailored to quantify continuous preferences based on choice experiments between pairs of stimuli. In particular, it is possible to explore determinants of interindividual variations in preferences, such as the height of the chooser. We collected data from a sample of 200 individuals from France. Measurements obtained show that the perception of attractiveness depends on both the height of the stimuli and the stature of the individual who judged them. Therefore, this study demonstrates that homogamy is present at the level of preferences for both sexes. We also show that measurements of the function describing this homogamy are concordant with several distinct mating rules proposed in the literature. In addition, the quantitative approach introduced here fulfills metrics that can be used to compare groups of individuals. In particular, our results reveal an important disagreement between sexes regarding height preferences in the context of mutual mate choice. Finally, both women and men prefer individuals who are significantly taller than average. All major findings are confirmed by a reanalysis of previously published data.

A Role for Ultrasonic Vocalisation in Social Communication and Divergence of Natural Populations of the House Mouse (Mus musculus domesticus)

PubMed Central

von Merten, Sophie; Hoier, Svenja

2014-01-01

It has long been known that rodents emit signals in the ultrasonic range, but their role in social communication and mating is still under active exploration. While inbred strains of house mice have emerged as a favourite model to study ultrasonic vocalisation (USV) patterns, studies in wild animals and natural situations are still rare. We focus here on two wild derived mouse populations. We recorded them in dyadic encounters for extended periods of time to assess possible roles of USVs and their divergence between allopatric populations. We have analysed song frequency and duration, as well as spectral features of songs and syllables. We show that the populations have indeed diverged in several of these aspects and that USV patterns emitted in a mating context differ from those emitted in same sex encounters. We find that females vocalize not less, in encounters with another female even more than males. This implies that the current focus of USVs being emitted mainly by males within the mating context needs to be reconsidered. Using a statistical syntax analysis we find complex temporal sequencing patterns that could suggest that the syntax conveys meaningful information to the receivers. We conclude that wild mice use USV for complex social interactions and that USV patterns can diverge fast between populations. PMID:24816836

Rapid evolution of cuticular hydrocarbons in a species radiation of acoustically diverse Hawaiian crickets (Gryllidae: trigonidiinae: Laupala).

PubMed

Mullen, Sean P; Mendelson, Tamra C; Schal, Coby; Shaw, Kerry L

2007-01-01

Understanding the origin and maintenance of barriers to gene exchange is a central goal of speciation research. Hawaiian swordtail crickets (genus Laupala) represent one of the most rapidly speciating animal groups yet identified. Extensive acoustic diversity, strong premating isolation, and female preference for conspecific acoustic signals in laboratory phonotaxis trials have strongly supported divergence in mate recognition as the driving force behind the explosive speciation seen in this system. However, recent work has shown that female preference for conspecific male calling song does not extend to mate choice at close range among these crickets, leading to the hypothesis that additional sexual signals are involved in mate recognition and premating isolation. Here we examine patterns of variation in cuticular lipids among several species of Laupala from Maui and the Big Island of Hawaii. Results demonstrate (1) a rapid and dramatic evolution of cuticular lipid composition among species in this genus, (2) significant differences among males and females in cuticular lipid composition, and (3) a significant reduction in the complexity of cuticular lipid profiles in species from the Big Island of Hawaii as compared to two outgroup species from Maui. These results suggest that behavioral barriers to gene exchange in Laupala may be composed of multiple mate recognition signals, a pattern common in other cricket species.

The effects of genotype, age, and social environment on male ornamentation, mating behavior, and attractiveness.

PubMed

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.

Assortative mating and fragmentation within dog breeds.

PubMed

Björnerfeldt, Susanne; Hailer, Frank; Nord, Maria; Vilà, Carles

2008-01-28

There are around 400 internationally recognized dog breeds in the world today, with a remarkable diversity in size, shape, color and behavior. Breeds are considered to be uniform groups with similar physical characteristics, shaped by selection rooted in human preferences. This has led to a large genetic difference between breeds and a large extent of linkage disequilibrium within breeds. These characteristics are important for association mapping of candidate genes for diseases and therefore make dogs ideal models for gene mapping of human disorders. However, genetic uniformity within breeds may not always be the case. We studied patterns of genetic diversity within 164 poodles and compared it to 133 dogs from eight other breeds. Our analyses revealed strong population structure within poodles, with differences among some poodle groups as pronounced as those among other well-recognized breeds. Pedigree analysis going three generations back in time confirmed that subgroups within poodles result from assortative mating imposed by breed standards as well as breeder preferences. Matings have not taken place at random or within traditionally identified size classes in poodles. Instead, a novel set of five poodle groups was identified, defined by combinations of size and color, which is not officially recognized by the kennel clubs. Patterns of genetic diversity in other breeds suggest that assortative mating leading to fragmentation may be a common feature within many dog breeds. The genetic structure observed in poodles is the result of local mating patterns, implying that breed fragmentation may be different in different countries. Such pronounced structuring within dog breeds can increase the power of association mapping studies, but also represents a serious problem if ignored. In dog breeding, individuals are selected on the basis of morphology, behaviour, working or show purposes, as well as geographic population structure. The same processes which have historically created dog breeds are still ongoing, and create further subdivision within current dog breeds.

Assortative mating and fragmentation within dog breeds

PubMed Central

2008-01-01

Background There are around 400 internationally recognized dog breeds in the world today, with a remarkable diversity in size, shape, color and behavior. Breeds are considered to be uniform groups with similar physical characteristics, shaped by selection rooted in human preferences. This has led to a large genetic difference between breeds and a large extent of linkage disequilibrium within breeds. These characteristics are important for association mapping of candidate genes for diseases and therefore make dogs ideal models for gene mapping of human disorders. However, genetic uniformity within breeds may not always be the case. We studied patterns of genetic diversity within 164 poodles and compared it to 133 dogs from eight other breeds. Results Our analyses revealed strong population structure within poodles, with differences among some poodle groups as pronounced as those among other well-recognized breeds. Pedigree analysis going three generations back in time confirmed that subgroups within poodles result from assortative mating imposed by breed standards as well as breeder preferences. Matings have not taken place at random or within traditionally identified size classes in poodles. Instead, a novel set of five poodle groups was identified, defined by combinations of size and color, which is not officially recognized by the kennel clubs. Patterns of genetic diversity in other breeds suggest that assortative mating leading to fragmentation may be a common feature within many dog breeds. Conclusion The genetic structure observed in poodles is the result of local mating patterns, implying that breed fragmentation may be different in different countries. Such pronounced structuring within dog breeds can increase the power of association mapping studies, but also represents a serious problem if ignored. In dog breeding, individuals are selected on the basis of morphology, behaviour, working or show purposes, as well as geographic population structure. The same processes which have historically created dog breeds are still ongoing, and create further subdivision within current dog breeds. PMID:18226210

Multifactorial inheritance with cultural transmission and assortative mating. II. a general model of combined polygenic and cultural inheritance.

PubMed Central

Cloninger, C R; Rice, J; Reich, T

1979-01-01

A general linear model of combined polygenic-cultural inheritance is described. The model allows for phenotypic assortative mating, common environment, maternal and paternal effects, and genic-cultural correlation. General formulae for phenotypic correlation between family members in extended pedigrees are given for both primary and secondary assortative mating. A FORTRAN program BETA, available upon request, is used to provide maximum likelihood estimates of the parameters from reported correlations. American data about IQ and Burks' culture index are analyzed. Both cultural and genetic components of phenotypic variance are observed to make significant and substantial contributions to familial resemblance in IQ. The correlation between the environments of DZ twins is found to equal that of singleton sibs, not that of MZ twins. Burks' culture index is found to be an imperfect measure of midparent IQ rather than an index of home environment as previously assumed. Conditions under which the parameters of the model may be uniquely and precisely estimated are discussed. Interpretation of variance components in the presence of assortative mating and genic-cultural covariance is reviewed. A conservative, but robust, approach to the use of environmental indices is described. PMID:453202

Colour change in a structural ornament is related to individual quality, parasites and mating patterns in the blue tit

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.

Polymorphic nuclear markers for coastal plant species with dynamic geographic distributions, the rock samphire (Crithmum maritimum) and the vulnerable dune pansy (Viola tricolor subsp. curtisii).

PubMed

Latron, Mathilde; Arnaud, Jean-François; Ferla, Héloïse; Godé, Cécile; Duputié, Anne

2018-06-01

Identifying spatial patterns of genetic differentiation across a species range is critical to set up conservation and restoration decision-making. This is especially timely, since global change triggers shifts in species' geographic distribution and in the geographical variation of mating system and patterns of genetic differentiation, with varying consequences at the trailing and leading edges of a species' distribution. Using 454 pyrosequencing, we developed nuclear microsatellite loci for two plant species showing a strictly coastal geographical distribution and contrasting range dynamics: the expanding rock samphire (Crithmum maritimum, 21 loci) and the highly endangered and receding dune pansy (Viola tricolor subsp. curtisii, 12 loci). Population genetic structure was then assessed by genotyping more than 100 individuals from four populations of each of the two target species. Rock samphire displayed high levels of genetic differentiation (F ST  = 0.38), and a genetic structure typical of a mostly selfing species (F IS ranging from 0.16 to 0.58). Populations of dune pansy showed a less pronounced level of population structuring (F ST  = 0.25) and a genotypic structure more suggestive of a mixed-mating system when excluding two loci with heterozygote excess. These results demonstrate that the genetic markers developed here are useful to assess the mating system of populations of these two species. They will be tools of choice to investigate phylogeographical patterns and variation in mating system over the geographical distribution ranges for two coastal plant species that are subject to dynamic evolution due to rapid contemporary global change.

Colour change in a structural ornament is related to individual quality, parasites and mating patterns in the blue tit.

PubMed

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.

Costs of mate-guarding in wild male long-tailed macaques (Macaca fascicularis): physiological stress and aggression.

PubMed

Girard-Buttoz, Cédric; Heistermann, Michael; Rahmi, Erdiansyah; Agil, Muhammad; Fauzan, Panji Ahmad; Engelhardt, Antje

2014-09-01

Mate-guarding is an important determinant of male reproductive success in a number of species. However, it is known to potentially incur costs. The aim of the present study was to assess the effect of mate-guarding on male physiological stress and aggression in long-tailed macaques, a species in which males mate-guard females to a lesser extent than predicted by the Priority of Access model (PoA). The study was carried out during two mating periods on three groups of wild long-tailed macaques in Indonesia by combining behavioral observations with non-invasive measurements of fecal glucocorticoid (fGC) levels. Mate-guarding was associated with a general rise in male stress hormone levels but, from a certain threshold of mate-guarding onwards, increased vigilance time was associated with a decrease in stress hormone output. Mate-guarding also increased male-male aggression rate and male vigilance time. Overall, alpha males were more physiologically stressed than other males independently of mating competition. Increased glucocorticoid levels during mate-guarding are most likely adaptive since it may help males to mobilize extra-energy required for mate-guarding and ultimately maintain a balanced energetic status. However, repeated exposure to high levels of stress over an extended period is potentially deleterious to the immune system and thus may carry costs. This potential physiological cost together with the cost of increased aggression mate-guarding male face may limit the male's ability to mate-guard females, explaining the deviance from the PoA model observed in long-tailed macaques. Comparing our results to previous findings we discuss how ecological factors, reproductive seasonality and rank achievement may modulate the extent to which costs of mate-guarding limit male monopolization abilities. Copyright © 2014. Published by Elsevier Inc.

The evolution of monogamy in response to partner scarcity

PubMed Central

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

The evolution of monogamy in response to partner scarcity.

PubMed

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.

Aluminum-activated citrate and malate transporters from the MATE and ALMT families function independently to confer Arabidopsis aluminum tolerance.

PubMed

Liu, Jiping; Magalhaes, Jurandir V; Shaff, Jon; Kochian, Leon V

2009-02-01

Aluminum-activated root malate and citrate exudation play an important role in plant Al tolerance. This paper characterizes AtMATE, a homolog of the recently discovered sorghum and barley Al-tolerance genes, shown here to encode an Al-activated citrate transporter in Arabidopsis. Together with the previously characterized Al-activated malate transporter, AtALMT1, this discovery allowed us to examine the relationship in the same species between members of the two gene families for which Al-tolerance genes have been identified. AtMATE is expressed primarily in roots and is induced by Al. An AtMATE T-DNA knockdown line exhibited very low AtMATE expression and Al-activated root citrate exudation was abolished. The AtALMT1 AtMATE double mutant lacked both Al-activated root malate and citrate exudation and showed greater Al sensitivity than the AtALMT1 mutant. Therefore, although AtALMT1 is a major contributor to Arabidopsis Al tolerance, AtMATE also makes a significant but smaller contribution. The expression patterns of AtALMT1 and AtMATE and the profiles of Al-activated root citrate and malate exudation are not affected by the presence or absence of the other gene. These results suggest that AtALMT1-mediated malate exudation and AtMATE-mediated citrate exudation evolved independently to confer Al tolerance in Arabidopsis. However, a link between regulation of expression of the two transporters in response to Al was identified through work on STOP1, a transcription factor that was previously shown to be necessary for AtALMT1 expression. Here we show that STOP1 is also required for AtMATE expression and Al-activated citrate exudation.

Female mating preferences and offspring survival: testing hypotheses on the genetic basis of mate choice in a wild lekking bird.

PubMed

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.

Sperm precedence in a novel context: mating in a sessile marine invertebrate with dispersing sperm.

PubMed

Bishop, J D; Pemberton, A J; Noble, L R

2000-06-07

The compound ascidian Diplosoma listerianum releases aquatic sperm which are dispersed passively to potential mates as individual gametes prior to storage of sperm, internal fertilization and brooding of embryos. The storage of exogenous sperm enables D. listerianum to produce a lengthy series of progeny following a brief period of mating. Molecular paternity analysis following sequential mating of colonies in laboratory culture revealed a consistent pattern with a clear initial bias in paternity towards the first of two acting males. The sites of sperm storage and fertilization and the morphology of the ovary in D. listerianum suggest that this bias reflects first-in-first-out use of individual stored gametes. The proportion of second-male paternity subsequently increased with time within the progeny arrays. This may have reflected the ageing or passive loss of first-male sperm. It is also possible that the modular nature of the organism contributed to this temporal trend: any recently budded colony modules maturing in the interval between matings would have been available exclusively to second-male sperm as virgin zooids. Two sets of mating trials were run. In the first, the collection of progeny suffered an interruption of 13 days and each male gained a larger proportion of recorded paternity within the progeny analysed when mating first rather than when mating second. In one mating combination, the first male obtained almost 100% of recorded paternity. In the second set of trials, with different clonal combinations, the complete sequence of progeny was collected and the estimated overall proportion of second-male paternity (P2) was consistently > 0.5. Taken as a whole, the results suggest that the overall P2-value can vary widely within the population studied. Proposed mechanisms of mating-order effects in species with copulatory mating include several which can have no counterpart in indirect aquatic mating since they involve the active removal, sealing off, volumetric displacement or incapacitation of first-male ejaculates. It is nevertheless clear that mating-order effects can be pronounced during the type of non-copulatory mating examined here, which is widespread in marine invertebrates.

Sperm precedence in a novel context: mating in a sessile marine invertebrate with dispersing sperm.

PubMed Central

Bishop, J D; Pemberton, A J; Noble, L R

2000-01-01

The compound ascidian Diplosoma listerianum releases aquatic sperm which are dispersed passively to potential mates as individual gametes prior to storage of sperm, internal fertilization and brooding of embryos. The storage of exogenous sperm enables D. listerianum to produce a lengthy series of progeny following a brief period of mating. Molecular paternity analysis following sequential mating of colonies in laboratory culture revealed a consistent pattern with a clear initial bias in paternity towards the first of two acting males. The sites of sperm storage and fertilization and the morphology of the ovary in D. listerianum suggest that this bias reflects first-in-first-out use of individual stored gametes. The proportion of second-male paternity subsequently increased with time within the progeny arrays. This may have reflected the ageing or passive loss of first-male sperm. It is also possible that the modular nature of the organism contributed to this temporal trend: any recently budded colony modules maturing in the interval between matings would have been available exclusively to second-male sperm as virgin zooids. Two sets of mating trials were run. In the first, the collection of progeny suffered an interruption of 13 days and each male gained a larger proportion of recorded paternity within the progeny analysed when mating first rather than when mating second. In one mating combination, the first male obtained almost 100% of recorded paternity. In the second set of trials, with different clonal combinations, the complete sequence of progeny was collected and the estimated overall proportion of second-male paternity (P2) was consistently > 0.5. Taken as a whole, the results suggest that the overall P2-value can vary widely within the population studied. Proposed mechanisms of mating-order effects in species with copulatory mating include several which can have no counterpart in indirect aquatic mating since they involve the active removal, sealing off, volumetric displacement or incapacitation of first-male ejaculates. It is nevertheless clear that mating-order effects can be pronounced during the type of non-copulatory mating examined here, which is widespread in marine invertebrates. PMID:10885515

Kinship and mate choice in a historic eastern Blue Ridge community, Madison County, Virginia.

PubMed

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.

Biochemical identification of mallard-black duck hybrids through a breeding program and in nature

USGS Publications Warehouse

Morgan, R.P.; Meritt, D.W.; Block, S.B.; Cole, M.

1978-01-01

From 1974 to 1976, a breeding program was used to produce black duck-mallard hybrids for the evaluation of inheritance patterns of serum proteins and esterases. In addition to the initial crosses, a series of matings in 1975 and 1976 were designed to evaluate inheritance patterns in hybrid matings with either black duck or mallards. At the F1 level, hybrids were easily distinguished. However, mallard or black duck crosses with hybrids were detectable as hybrids in only 11.5 - 22.6% of the progeny using serum proteins, and 22.6 - 38.8% using serum esterases. Concurrent with the breeding program, a field survey indicated hybrid frequencies ranging from 4% to 28%.

Why do males choose heterospecific females in the red spider mite?

PubMed

Sato, Yukie; Staudacher, Heike; Sabelis, Maurice W

2016-01-01

In some species, males readily show courtship behaviour towards heterospecific females and even prefer them to females of their own species. This behaviour is generally explained by indiscriminate mating to acquire more mates, but may partly be explained by male mate preference mechanisms that have developed to choose among conspecific females, as male preference for larger females causes mating with larger heterospecific females. Recently, we found that males of the red spider mite, Tetranychus evansi collected from Spain (invasive population), prefer to mate with females of the two-spotted spider mite, T. urticae rather than with conspecific females. In spider mites, mate preference for non-kin individuals has been observed. Here, we investigated if T. evansi males collected from the area of its origin (Brazil) also show preference for heterospecific females. Secondly, we investigated if mate preference of T. evansi males for heterospecific females is affected by their relatedness to conspecific females which are offered together with heterospecific females. We found that mate preference for heterospecific females exists in Brazilian T. evansi, suggesting that the preference for heterospecific females is not a lack of evolved premating isolation with an allopatric species. We found that T. evansi males showed lower propensity to mate with heterospecific females when alternative females were non-kin in the two iso-female lines collected from Brazil. However, the effect of relatedness on male mate preference was not significant. We discuss alternative hypotheses explaining why T. evansi males prefer to mate with T. urticae females.

Effects of range-wide variation in climate and isolation on floral traits and reproductive output of Clarkia pulchella.

PubMed

Bontrager, Megan; Angert, Amy L

2016-01-01

Plant mating systems and geographic range limits are conceptually linked by shared underlying drivers, including landscape-level heterogeneity in climate and in species' abundance. Studies of how geography and climate interact to affect plant traits that influence mating system and population dynamics can lend insight to ecological and evolutionary processes shaping ranges. Here, we examined how spatiotemporal variation in climate affects reproductive output of a mixed-mating annual, Clarkia pulchella. We also tested the effects of population isolation and climate on mating-system-related floral traits across the range. We measured reproductive output and floral traits on herbarium specimens collected across the range of C. pulchella. We extracted climate data associated with specimens and derived a population isolation metric from a species distribution model. We then examined how predictors of reproductive output and floral traits vary among populations of increasing distance from the range center. Finally, we tested whether reproductive output and floral traits vary with increasing distance from the center of the range. Reproductive output decreased as summer precipitation decreased, and low precipitation may contribute to limiting the southern and western range edges of C. pulchella. High spring and summer temperatures are correlated with low herkogamy, but these climatic factors show contrasting spatial patterns in different quadrants of the range. Limiting factors differ among different parts of the range. Due to the partial decoupling of geography and environment, examining relationships between climate, reproductive output, and mating-system-related floral traits reveals spatial patterns that might be missed when focusing solely on geographic position. © 2016 Botanical Society of America.

Experimental hybridization and backcrossing reveal forces of reproductive isolation in Microbotryum

PubMed Central

2013-01-01

Background Hybridization and reproductive isolation are central to the origin and maintenance of species, and especially for sympatric species, gene flow is often inhibited through barriers that depend upon mating compatibility factors. The anther-smut fungi (genus Microbotryum) serve as models for speciation in the face of sympatry, and previous studies have tested for but not detected assortative mating. In addition, post-mating barriers are indicated by reduced fitness of hybrids, but sources of those barriers (i.e. ecological maladaptation or genetic incompatibilities) have not yet been detected. Here, backcrossing experiments, specifically controlling for the fungal species origins of the mating compatibility factors, were used to investigate reproductive isolation in the recently-derived species Microbotryum lychnidis-dioicae and Microbotryum silenes-dioicae. Results Assortative mating was detected during backcrossing and was manifested by the preferential conjugation of the hybrid-produced gametes with non-hybrid gametes containing mating compatibility factors from the same parental species. Patterns of post-mating performance supported either a level of extrinsic isolation mechanism, where backcross progeny with a higher proportion of the pathogen genome adapted to the particular host environment were favored, or an infection advantage attributed to greater genetic contribution to the hybrid from the M. lychnidis-dioicae genome. Conclusion The use of controlled backcrossing experiments reveals significant species-specific mating type effects on conjugations between recently-derived sister species, which are likely to play important roles in both maintaining species separation and the nature of hybrids lineages that emerge in sympatry between Microbotryum species. PMID:24112452

Intrasexual competition in females: evidence for sexual selection?

PubMed

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.

Intrasexual competition in females: evidence for sexual selection?

PubMed Central

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

Mating-related behaviour of grizzly bears inhabiting marginal habitat at the periphery of their North American range.

PubMed

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.

Selection on male sex pheromone composition contributes to butterfly reproductive isolation

PubMed Central

Bacquet, P. M. B.; Brattström, O.; Wang, H.-L.; Allen, C. E.; Löfstedt, C.; Brakefield, P. M.; Nieberding, C. M.

2015-01-01

Selection can facilitate diversification by inducing character displacement in mate choice traits that reduce the probability of maladaptive mating between lineages. Although reproductive character displacement (RCD) has been demonstrated in two-taxa case studies, the frequency of this process in nature is still debated. Moreover, studies have focused primarily on visual and acoustic traits, despite the fact that chemical communication is probably the most common means of species recognition. Here, we showed in a large, mostly sympatric, butterfly genus, a strong pattern of recurrent RCD for predicted male sex pheromone composition, but not for visual mate choice traits. Our results suggest that RCD is not anecdotal, and that selection for divergence in male sex pheromone composition contributed to reproductive isolation within the Bicyclus genus. We propose that selection may target olfactory mate choice traits as a more common sensory modality to ensure reproductive isolation among diverging lineages than previously envisaged. PMID:25740889

Multiple Mating, Paternity and Complex Fertilisation Patterns in the Chokka Squid Loligo reynaudii

PubMed Central

Naud, Marie-Jose; Sauer, Warwick H. H.; McKeown, Niall J.; Shaw, Paul W.

2016-01-01

Polyandry is widespread and influences patterns of sexual selection, with implications for sexual conflict over mating. Assessing sperm precedence patterns is a first step towards understanding sperm competition within a female and elucidating the roles of male- and female-controlled factors. In this study behavioural field data and genetic data were combined to investigate polyandry in the chokka squid Loligo reynaudii. Microsatellite DNA-based paternity analysis revealed multiple paternity to be the norm, with 79% of broods sired by at least two males. Genetic data also determined that the male who was guarding the female at the moment of sampling was a sire in 81% of the families tested, highlighting mate guarding as a successful male tactic with postcopulatory benefits linked to sperm deposition site giving privileged access to extruded egg strings. As females lay multiple eggs in capsules (egg strings) wherein their position is not altered during maturation it is possible to describe the spatial / temporal sequence of fertilisation / sperm precedence There were four different patterns of fertilisation found among the tested egg strings: 1) unique sire; 2) dominant sire, with one or more rare sires; 3) randomly mixed paternity (two or more sires); and 4) a distinct switch in paternity occurring along the egg string. The latter pattern cannot be explained by a random use of stored sperm, and suggests postcopulatory female sperm choice. Collectively the data indicate multiple levels of male- and female-controlled influences on sperm precedence, and highlights squid as interesting models to study the interplay between sexual and natural selection. PMID:26872354

Weighing costs and benefits of mating in bushcrickets (Insecta: Orthoptera: Tettigoniidae), with an emphasis on nuptial gifts, protandry and mate density

PubMed Central

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

The complex interplay between macronutrient intake, cuticular hydrocarbon expression and mating success in male decorated crickets.

PubMed

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.

Both Geography and Ecology Contribute to Mating Isolation in Guppies

PubMed Central

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

A Twin-Family Study of General IQ

ERIC Educational Resources Information Center

van Leeuwen, Marieke; van den Berg, Stephanie M.; Boomsma, Dorret I.

2008-01-01

In this paper we assess the presence of assortative mating, gene-environment interaction and the heritability of intelligence in childhood using a twin family design with twins, their siblings and parents from 112 families. We evaluate two competing hypotheses about the cause of assortative mating in intelligence: social homogamy and phenotypic…

Associating sex-biased and seasonal behaviour with contact patterns and transmission risk in Gopherus agassizii

USGS Publications Warehouse

Aiello, Christina M.; Esque, Todd; Nussear, K. E.; Emblidge, P. G.; Hudson, P. J.

2018-01-01

Interactions between wildlife hosts act as transmission routes for directly transmitted pathogens and vary in ways that affect transmission efficiency. Identifying drivers of contact variation can allow both contact inference and estimation of transmission dynamics despite limited data. In desert tortoises, mating strategy, burrow use and seasonal change influence numerous behaviours and likely shape contact patterns. In this study, we ask to what extent tortoise contact behaviour varies between sexes and seasons, and whether space or burrow-use data can be used to infer contact characteristics consistent with those recorded by proximity loggers. We identified sex and season-biased contact behaviour in both wild and captive populations indicative of female-female avoidance and seasonal male mate-seeking behaviour. Space and burrow-use patterns were informative, but did not always predict the extent of sex or seasonal biases on contact. We discuss the implications these findings have for transmission patterns and disease mitigation in tortoise populations.

Pleiotropic Effects of DDT Resistance on Male Size and Behaviour.

PubMed

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.

Computational mate choice: theory and empirical evidence.

PubMed

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.

RNA-sequencing elucidates the regulation of behavioural transitions associated with the mating process in honey bee queens.

PubMed

Manfredini, Fabio; Brown, Mark J F; Vergoz, Vanina; Oldroyd, Benjamin P

2015-07-31

Mating is a complex process, which is frequently associated with behavioural and physiological changes. However, understanding of the genetic underpinnings of these changes is limited. Honey bees are both a model system in behavioural genomics, and the dominant managed pollinator of human crops; consequently understanding the mating process has both pure and applied value. We used next-generation transcriptomics to probe changes in gene expression in the brains of honey bee queens, as they transition from virgin to mated reproductive status. In addition, we used CO2-narcosis, which induces oviposition without mating, to isolate the process of reproductive maturation. The mating process produced significant changes in the expression of vision, chemo-reception, metabolic, and immune-related genes. Differential expression of these genes maps clearly onto known behavioural and physiological changes that occur during the transition from being a virgin queen to a newly-mated queen. A subset of these changes in gene expression were also detected in CO2-treated queens, as predicted from previous physiological studies. In addition, we compared our results to previous studies that used microarray techniques across a range of experimental time-points. Changes in expression of immune- and vision-related genes were common to all studies, supporting an involvement of these groups of genes in the mating process. Our study is an important step in understanding the molecular mechanisms regulating post-mating behavioural transitions in a natural system. The weak overlap in patterns of gene expression with previous studies demonstrates the high sensitivity of genome-wide approaches. Thus, while we build on previous microarray studies that explored post-mating changes in honey bees, the broader experimental design, use of RNA-sequencing, and focus on Australian honey bees, which remain free from the devastating parasite Varroa destructor, in the current study, provide unique insights into the biology of the mating process in honey bees.

Cytonuclear Theory for Haplodiploid Species and X-Linked Genes. I. Hardy-Weinberg Dynamics and Continent-Island, Hybrid Zone Models

PubMed Central

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

Parental conflict in birds: comparative analyses of offspring development, ecology and mating opportunities.

PubMed

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.

Does Higher Education Expansion Promote Educational Homogamy? Evidence from Married Couples of the Post-80s Generation in Shanghai, China

PubMed Central

Hu, Anning; Qian, Zhenchao

2017-01-01

The expansion of higher education witnessed in many societies influences the pattern of educational assortative mating. Structural transition theory predicts growing educational homogamy due to increasing preference for highly-educated partners who become more widely available. In contrast, social closure theory suggests depressed educational homogamy because the inflation of the education elite circle fosters the openness of marriage market, reducing the preference for a highly-educated mate and increasing the penetrability across social-status boundaries. Capitalizing the survey data that are representative of the post-80s one-child generation collected in Shanghai, China, we test the hypotheses derived from the two theories. Empirical results suggest that, with increasing availability of highly educated individuals, the extent of educational homogamy by birth cohort reveals a U-shaped pattern. This U-shaped pattern demonstrates increasing levels of educational homogamy and lends support to structural transition theory. PMID:27712675

An integrative mating system assessment of a nonmodel, economically important Pacific rockfish (Sebastes melanops) reveals nonterritorial polygamy and conservation implications for a large species flock.

PubMed

Karageorge, Kurt W; Wilson, Raymond R

2017-12-01

Characterizing the mating systems of long-lived, economically important Pacific rockfishes comprising the viviparous Sebastes species flock is crucial for their conservation. However, direct assignment of mating success to sires is precluded by open, offshore populations and high female fecundity. We addressed this challenge by integrating paternity-assigned mating success of females with the adult sex ratio (ASR) of the population, male evolutionary responses to receptive females, and reproductive life history traits-in the framework of sexual selection theory-to assess the mating system of Sebastes melanops . Microsatellite parentage analysis of 17 pregnant females, 1,256 of their progeny, and 106 adults from the population yielded one to four sires per brood, a mean of two sires, and a female mate frequency distribution with a truncated normal (random) pattern. The 11 multiple paternity broods all contained higher median allele richness than the six single paternity broods (Wilcoxon test: W  = 0, p  < .001), despite similar levels of average heterozygosity. By sampling sperm and alleles from different males, polyandrous females gain opportunities to enhance their sperm supply and to lower the cost of mating with genetically incompatible males through reproductive compensation. A mean of two mates per mated female with a variance of one, an ASR = 1.2 females per male, and the expected population mean of 2.4 mates for mated males (and the estimated 35 unavailable sires), fits polygamous male mate frequency distributions that distinguish polygynandry and polyandrogyny mating systems, that is, variations of polygamy, but not polyandry. Inference for polygamy is consistent with weak premating sexual selection on males, expected in mid-water, schooling S. melanops , owing to polyandrous mating, moderately aggregated receptive females, an even ASR, and no territories and nests used for reproduction. Each of these characteristics facilitates more mating males and erodes conspicuous sexual dimorphism. Evaluation of male evolutionary responses of demersal congeners that express reproductively territorial behavior revealed they have more potential mechanisms for producing premating sexual selection, greater variation in reproductive success, and a reduced breeding effective population size of adults and annual effective size of a cohort, compared to S. melanops modeled with two mates per adult. Such divergence in behavior and mating system by territorial species may differentially lower their per capita birth rates, subsequent population growth, and slow their recovery from exploitation.

The impact of sex-role reversal on the diversity of the major histocompatibility complex: insights from the seahorse (Hippocampus abdominalis).

PubMed

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.

LC-UV assay method and UPLC/Q-TOF-MS characterisation of saponins from Ilex paraguariensis A. St. Hil. (mate) unripe fruits.

PubMed

Peixoto, Maria Paula Garofo; Kaiser, Samuel; Verza, Simone Gasparin; de Resende, Pedro Ernesto; Treter, Janine; Pavei, Cabral; Borré, Gustavo Luís; Ortega, George González

2012-01-01

Ilex paraguariensis A. St. Hil. (mate) is known in several South American countries because of the use of its leaves in stimulant herbal beverages. High saponin contents were reported in mate leaves and unripe fruits that possess a dissimilar composition. Two LC-UV methods previously reported for mate saponins assay focused on mate leaves and the quantification of the less polar saponin fraction in mate fruits. To develop and validate a LC-UV method to assay the total content of saponins in unripe mate fruits and characterise the chemical structure of triterpenic saponins by UPLC/Q-TOF-MS. From unripe fruits of mate a crude ethanolic extract was prepared (EX40) and the mate saponin fraction (MSF) purified by solid phase extraction. The LC-UV method was validated using ilexoside II as external standard. UPLC/Q-TOF-MS was adjusted from the LC-UV method to obtain the fragmentation patterns of the main saponins present in unripe fruits. Both LC-UV and UPLC/Q-TOF-MS methods indicate a wide range of Ilex saponins polarity. The ilexoside II and total saponin content of EX40 were 8.20% (w/w) and 47.60% (w/w), respectively. The total saponin content in unripe fruits was 7.28% (w/w). The saponins present in MSF characterised by UPLC/Q-TOF-MS are derived mainly from ursolic/oleanolic, acetyl ursolic or pomolic acid. The validated LC-UV method was shown to be linear, precise, accurate and to cover several saponins previously isolated from Ilex species and could be applied for the quality control of unripe fruit saponins. Copyright © 2011 John Wiley & Sons, Ltd.

Social biases determine spatiotemporal sparseness of ciliate mating heuristics.

PubMed

Clark, Kevin B

2012-01-01

Ciliates become highly social, even displaying animal-like qualities, in the joint presence of aroused conspecifics and nonself mating pheromones. Pheromone detection putatively helps trigger instinctual and learned courtship and dominance displays from which social judgments are made about the availability, compatibility, and fitness representativeness or likelihood of prospective mates and rivals. In earlier studies, I demonstrated the heterotrich Spirostomum ambiguum improves mating competence by effecting preconjugal strategies and inferences in mock social trials via behavioral heuristics built from Hebbian-like associative learning. Heuristics embody serial patterns of socially relevant action that evolve into ordered, topologically invariant computational networks supporting intra- and intermate selection. S. ambiguum employs heuristics to acquire, store, plan, compare, modify, select, and execute sets of mating propaganda. One major adaptive constraint over formation and use of heuristics involves a ciliate's initial subjective bias, responsiveness, or preparedness, as defined by Stevens' Law of subjective stimulus intensity, for perceiving the meaningfulness of mechanical pressures accompanying cell-cell contacts and additional perimating events. This bias controls durations and valences of nonassociative learning, search rates for appropriate mating strategies, potential net reproductive payoffs, levels of social honesty and deception, successful error diagnosis and correction of mating signals, use of insight or analysis to solve mating dilemmas, bioenergetics expenditures, and governance of mating decisions by classical or quantum statistical mechanics. I now report this same social bias also differentially affects the spatiotemporal sparseness, as measured with metric entropy, of ciliate heuristics. Sparseness plays an important role in neural systems through optimizing the specificity, efficiency, and capacity of memory representations. The present findings indicate sparseness performs a similar function in single aneural cells by tuning the size and density of encoded computational architectures useful for decision making in social contexts.

Social biases determine spatiotemporal sparseness of ciliate mating heuristics

PubMed Central

2012-01-01

Ciliates become highly social, even displaying animal-like qualities, in the joint presence of aroused conspecifics and nonself mating pheromones. Pheromone detection putatively helps trigger instinctual and learned courtship and dominance displays from which social judgments are made about the availability, compatibility, and fitness representativeness or likelihood of prospective mates and rivals. In earlier studies, I demonstrated the heterotrich Spirostomum ambiguum improves mating competence by effecting preconjugal strategies and inferences in mock social trials via behavioral heuristics built from Hebbian-like associative learning. Heuristics embody serial patterns of socially relevant action that evolve into ordered, topologically invariant computational networks supporting intra- and intermate selection. S. ambiguum employs heuristics to acquire, store, plan, compare, modify, select, and execute sets of mating propaganda. One major adaptive constraint over formation and use of heuristics involves a ciliate’s initial subjective bias, responsiveness, or preparedness, as defined by Stevens’ Law of subjective stimulus intensity, for perceiving the meaningfulness of mechanical pressures accompanying cell-cell contacts and additional perimating events. This bias controls durations and valences of nonassociative learning, search rates for appropriate mating strategies, potential net reproductive payoffs, levels of social honesty and deception, successful error diagnosis and correction of mating signals, use of insight or analysis to solve mating dilemmas, bioenergetics expenditures, and governance of mating decisions by classical or quantum statistical mechanics. I now report this same social bias also differentially affects the spatiotemporal sparseness, as measured with metric entropy, of ciliate heuristics. Sparseness plays an important role in neural systems through optimizing the specificity, efficiency, and capacity of memory representations. The present findings indicate sparseness performs a similar function in single aneural cells by tuning the size and density of encoded computational architectures useful for decision making in social contexts. PMID:22482001

REINFORCEMENT OF STICKLEBACK MATE PREFERENCES: SYMPATRY BREEDS CONTEMPT.

PubMed

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.

A Novel Quantitative Approach to Women’s Reproductive Strategies

PubMed Central

Milne, Fritha H.; Judge, Debra S.

2012-01-01

The patterned way in which individuals allocate finite resources to various components of reproduction (e.g. mating effort, reproductive timing and parental investment) is described as a reproductive strategy. As energy is limited, trade-offs between and within aspects of reproductive strategies are expected. The first aim of this study was to derive aspects of reproductive strategies using complete reproductive histories from 718 parous Western Australian women. Factor analysis using a subset of these participants resulted in six factors that represented ‘short-term mating strategy’, ‘early onset of sexual activity’, ‘reproductive output’, ‘timing of childbearing’, ‘breastfeeding’, and ‘child spacing’. This factor structure was internally validated by replication using a second independent subset of the data. The second aim of this study examined trade-offs between aspects of reproductive strategies derived from aim one. Factor scores calculated for each woman were incorporated in generalised linear models and interaction terms were employed to examine the effect of mating behaviour on the relationships between reproductive timing, parental investment and overall reproductive success. Early sexual activity correlates with early reproductive onset for women displaying more long-term mating strategies. Women with more short-term mating strategies exhibit a trade-off between child quantity and child quality not observed in women with a long-term mating strategy. However, women with a short-term mating strategy who delay reproductive timing exhibit levels of parental investment (measured as breastfeeding duration per child) similar to that of women with long-term mating strategies. Reproductive delay has fitness costs (fewer births) for women displaying more short-term mating strategies. We provide empirical evidence that reproductive histories of contemporary women reflect aspects of reproductive strategies, and associations between these strategic elements, as predicted from life history theory. PMID:23056440

Consequences of mating and predation risk for longevity in a freshwater snail: abstinence makes the heart beat longer.

PubMed

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.

Inbreeding in Southeastern Spain : The Impact of Geography and Demography on Marital Mobility and Marital Distance Patterns (1900-1969).

PubMed

Calderón, R; Hernández, C L; García-Varela, G; Masciarelli, D; Cuesta, P

2018-03-01

In this paper, the structure of a southeastern Spanish population was studied for the first time with respect to its inbreeding patterns and its relationship with demographic and geographic factors. Data on consanguineous marriages (up to second cousins) from 1900 to 1969 were taken from ecclesiastic dispensations. Our results confirm that the patterns and trends of inbreeding in the study area are consistent with those previously observed in most non-Cantabrian Spanish populations. The rate of consanguineous marriages was apparently stable between 1900 and 1935 and then sharply decreased since 1940, which coincides with industrialization in Spain. A marked departure from Hardy-Weinberg expectations (0.25) in the ratio of first cousin (M22) to second cousin (M33) marriages in the study population (0.88) was observed. The high levels of endogamy (>80%) and its significant steadiness throughout the twentieth century is noteworthy. Accordingly, our results show that exogamous marriages were not only poorly represented but also that this reduced mobility (<6 km) suggests that the choice of a mate was preferentially local. We found higher mobility in M22 with respect to M33 cousin mating. The relationships between population size and consanguinity rates and inbreeding fit power-law distributions. A significant positive correlation was observed between inbreeding and elevation. Many Spanish populations have experienced a prolonged and considerable isolation across generations, which has led to high proportions of historical and local endogamy that is associated, in general, with high [Formula: see text] values. Thus, assessing genomic inbreeding using runs of homozygosity (ROH) in current Spanish populations could be an additional pertinent strategy for obtaining a more refined perspective regarding the population history inferred from the extent and frequency of ROH regions.

Evolution of premating reproductive isolation among conspecific populations of the sea rock-pool beetle Ochthebius urbanelliae driven by reinforcing natural selection.

PubMed

Porretta, Daniele; Urbanelli, Sandra

2012-04-01

How natural selection might be involved in speciation remains a fundamental question in evolutionary biology. When two or more species co-occur in the same areas, natural selection may favor divergence in mating traits. By acting in sympatric but not allopatric populations, natural selection can also affect mate choice within species and ultimately initiate speciation among conspecific populations. Here, we address this potential effect in the sea rock-pool beetles Ochthebius quadricollis and O. urbanelliae. The two species, which inhabit the Mediterranean coasts, co-occurr syntopically in an area along the Italian Tyrrhenian coast and completed reproductive isolation by reinforcement. In this article, through mating trials under laboratory conditions between conspecific populations, we found in O. quadricollis no deviations from random mating. Conversely, in O. urbanelliae, we found a clear pattern of premating isolation between the reinforced populations sympatric with O. quadricollis and those nonreinforced allopatric. This pattern is consistent with the view that natural selection, which completed the reproductive isolation between the two species in sympatry, led incidentally also to partial premating reproductive isolation (I(PSI) estimator from 0.683 to 0.792) between conspecific populations of O. urbanelliae. This case study supports an until recently underappreciated role of natural selection resulting from species interactions in initiating speciation. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

The causes of variation in the presence of genetic covariance between sexual traits and preferences.

PubMed

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.

Mate choice for major histocompatibility complex complementarity in a strictly monogamous bird, the grey partridge (Perdix perdix).

PubMed

Rymešová, Dana; Králová, Tereza; Promerová, Marta; Bryja, Josef; Tomášek, Oldřich; Svobodová, Jana; Šmilauer, Petr; Šálek, Miroslav; Albrecht, Tomáš

2017-01-01

Sexual selection has been hypothesised as favouring mate choice resulting in production of viable offspring with genotypes providing high pathogen resistance. Specific pathogen recognition is mediated by genes of the major histocompatibility complex (MHC) encoding proteins fundamental for adaptive immune response in jawed vertebrates. MHC genes may also play a role in odour-based individual recognition and mate choice, aimed at avoiding inbreeding. MHC genes are known to be involved in mate choice in a number of species, with 'good genes' (absolute criteria) and 'complementary genes' (self-referential criteria) being used to explain MHC-based mating. Here, we focus on the effect of morphological traits and variation and genetic similarity between individuals in MHC class IIB (MHCIIB) exon 2 on mating in a free-living population of a monogamous bird, the grey partridge. We found no evidence for absolute mate choice criteria as regards grey partridge MHCIIB genotypes, i.e., number and occurrence of amino acid variants, though red chroma of the spot behind eyes was positively associated with male pairing success. On the other hand, mate choice at MHCIIB was based on relative criteria as females preferentially paired with more dissimilar males having a lower number of shared amino acid variants. This observation supports the 'inbreeding avoidance' and 'complementary genes' hypotheses. Our study provides one of the first pieces of evidence for MHC-based mate choice for genetic complementarity in a strictly monogamous bird. The statistical approach employed can be recommended for testing mating preferences in cases where availability of potential mates (recorded with an appropriate method such as radio-tracking) shows considerable temporal variation. Additional genetic analyses using neutral markers may detect whether MHC-based mate choice for complementarity emerges as a by-product of general inbreeding avoidance in grey partridges.

The Evolution of Autistic-Like and Schizotypal Traits: A Sexual Selection Hypothesis

PubMed Central

Del Giudice, Marco; Angeleri, Romina; Brizio, Adelina; Elena, Marco R.

2010-01-01

In this paper we present a new hypothesis on the evolution of autistic-like and schizotypal personality traits. We argue that autistic-like and schizotypal traits contribute in opposite ways to individual differences in reproductive and mating strategies, and have been maintained – at least in part – by sexual selection through mate choice. Whereas positive schizotypy can be seen as a psychological phenotype oriented to high-mating effort and good genes displays in both sexes, autistic-like traits in their non-pathological form contribute to a male-typical strategy geared toward high parental investment, low-mating effort, and long-term resource allocation. At the evolutionary-genetic level, this sexual selection hypothesis is consistent with Crespi and Badcock's “imprinted brain” theory of autism and psychosis; the effect of offspring mating behavior on resource flow within the family connects sexual selection with genomic imprinting in the context of human biparental care. We conclude by presenting the results of an empirical study testing one of the predictions derived from our hypothesis. In a sample of 199 college students, autistic-like traits predicted lower interest in short-term mating, higher partner-specific investment, and stronger commitment to long-term romantic relations, whereas positive schizotypy showed the opposite pattern of effects. PMID:21833210

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

Ovule positions within linear fruit are correlated with nonrandom mating in Robinia pseudoacacia

PubMed Central

Yuan, Cunquan; Sun, Yuhan; Sun, Peng; Li, Yunfei; Hu, Ruiyang; Zhao, Keqi; Wang, Jinxing; Li, Yun

2016-01-01

Post-pollination processes can lead to nonrandom mating among compatible pollen donors. Moreover, morphological patterns of ovule development within linear fruits are reportedly nonrandom and depend on ovule position. However, little is known about the relationship between nonrandom mating and ovule position within linear fruit. Here, we combined controlled pollen competition experiments and paternity analyses on R. pseudoacacia to better understand nonrandom mating and its connection with ovule position. Molecular determination of siring success showed a significant departure from the expected ratio based on each kind of pollen mixture, suggesting a nonrandom mating. Outcrossed pollen grains, which were strongly favored, produced significantly more progeny than other pollen grains. Paternity analyses further revealed that the distribution of offspring produced by one specific pollen source was also nonrandom within linear fruit. The stylar end, which has a higher probability of maturation, produced a significantly higher number of outcrossed offspring than other offspring, suggesting a correlation between pollen source and ovule position. Our results suggested that a superior ovule position exists within the linear fruit in R. pseudoacacia, and the pollen that was strongly favored often preferentially occupies the ovules that were situated in a superior position, which ensured siring success and facilitated nonrandom mating. PMID:27819357

Patterns of racial and educational assortative mating in Brazil.

PubMed

Gullickson, Aaron; Torche, Florencia

2014-06-01

Exchange of racial for educational status has been documented for black/white marriages in the United States. Exchange may be an idiosyncratic feature of U.S. society, resulting from unusually strong racial boundaries historically developed there. We examine status exchange across racial lines in Brazil. In contrast to the United States, Brazil features greater fluidity of racial boundaries and a middle tier of "brown" individuals. If exchange is contingent on strong racial boundaries, it should be weak or non-existent in Brazilian society. Contrary to this expectation, we find strong evidence of status exchange. However, this pattern results from a generalized penalty for darkness, which induces a negative association between higher education and marrying darker spouses ("market exchange") rather than from a direct trading of resources by partners ("dyadic exchange"). The substantive and methodological distinction between market and dyadic exchange helps clarify and integrate prior findings in the status exchange literature.

Multiple mating and clutch size in invertebrate brooders versus pregnant vertebrates

PubMed Central

Avise, John C.; Tatarenkov, Andrey; Liu, Jin-Xian

2011-01-01

We summarize the genetic literature on polygamy rates and sire numbers per clutch in invertebrate animals that brood their offspring and then compare findings with analogous data previously compiled for vertebrate species displaying viviparity or other pregnancy-like syndromes. As deduced from molecular parentage analyses of several thousand broods from more than 100 “pregnant” species, invertebrate brooders had significantly higher mean incidences of multiple mating than pregnant vertebrates, a finding generally consistent with the postulate that clutch size constrains successful mate numbers in species with extended parental care. However, we uncovered no significant correlation in invertebrates between brood size and genetically deduced rates of multiple mating by the incubating sex. Instead, in embryo-gestating animals otherwise as different as mammals and mollusks, polygamy rates and histograms of successful mates per brooder proved to be strikingly similar. Most previous studies have sought to understand why gestating parents have so many mates and such high incidences of successful multiple mating; an alternative perspective based on logistical constraints turns the issue on its head by asking why mate numbers and polygamy rates are much lower than they theoretically could be, given the parentage-resolving power of molecular markers and the huge sizes of many invertebrate broods. PMID:21709247

Mating experience and food deprivation modulate odor preference and dispersal in Drosophila melanogaster males

PubMed Central

Wang, Shu-Ping; Guo, Wei-Yan; Muhammad, Shahid Arain; Chen, Rui-Rui; Mu, Li-Li; Li, Guo-Qing

2014-01-01

Abstract Rotting fruits offer all of the known resources required for the livelihood of Drosophila melanogaster Meigen (Diptera: Drosophilidae). During fruit fermentation, carbohydrates and proteins are decomposed to produce volatile alcohols and amines, respectively. It is hypothesized that D. melanogaster adults can detect these chemical cues at a distance to identify and locate the decaying fruits. In the present paper, we compared the olfactory responses and movement of male flies varying in mating status and nutritional state to methanol, ethanol, and ammonia sources using a glass Y-tube olfactometer. In general, ethanol vapor at low to moderate concentrations repelled more hungry mated males than satiated ones. In contrast, methanol showed little difference in the attractiveness to males at different nutritional states and mating status. Moreover, ammonia attracted more hungry mated males. The attractiveness increased almost linearly with ammonia concentration from lowest to highest. When ammonia and artificial diet were put together in the odor arm, the responses of male flies to mixed odor mimicked the response to ammonia. Furthermore, odorant concentration, mating status, and nutritional state affected the flies’ dispersal. Mated and starved males dispersed at a higher rate than virgin and satiated ones. Thus, our results showed that starved, mated males increased dispersal and preferred ammonia that originated from protein. PMID:25368075

Sexual conflict arising from extrapair matings in birds.

PubMed

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.

Sexual selection and the risk of extinction in birds.

PubMed Central

Morrow, Edward H; Pitcher, Trevor E

2003-01-01

The relationship between sexual selection and extinction risk has rarely been investigated. This is unfortunate because extinction plays a key role in determining the patterns of species richness seen in extant clades, which form the basis of comparative studies into the role that sexual selection may play in promoting speciation. We investigate the extent to which the perceived risk of extinction relates to four different estimates of sexual selection in 1030 species of birds. We find no evidence that the number of threatened species is distributed unevenly according to a social mating system, and neither of our two measures of pre-mating sexual selection (sexual dimorphism and dichromatism) was related to extinction risk, after controlling for phylogenetic inertia. However, threatened species apparently experience more intense post-mating sexual selection, measured as testis size, than non-threatened species. These results persisted after including body size as a covariate in the analysis, and became even stronger after controlling for clutch size (two known correlates of extinction risk). Sexual selection may therefore be a double-edged process-promoting speciation on one hand but promoting extinction on the other. Furthermore, we suggest that it is post-mating sexual selection, in particular, that is responsible for the negative effect of sexual selection on clade size. Why this might be is unclear, but the mean population fitness of species with high intensities of post-mating sexual selection may be especially low if costs associated with multiple mating are high or if the selection load imposed by post-mating selection is higher relative to that of pre-mating sexual selection. PMID:12964981

Sexual Conflict Arising from Extrapair Matings in Birds

PubMed Central

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

Paternity analysis reveals wide pollen dispersal and high multiple paternity in a small isolated population of the bird-pollinated Eucalyptus caesia (Myrtaceae).

PubMed

Bezemer, N; Krauss, S L; Phillips, R D; Roberts, D G; Hopper, S D

2016-12-01

Optimal foraging behaviour by nectavores is expected to result in a leptokurtic pollen dispersal distribution and predominantly near-neighbour mating. However, complex social interactions among nectarivorous birds may result in different mating patterns to those typically observed in insect-pollinated plants. Mating system, realised pollen dispersal and spatial genetic structure were examined in the bird-pollinated Eucalyptus caesia, a species characterised by small, geographically disjunct populations. Nine microsatellite markers were used to genotype an entire adult stand and 181 seeds from 28 capsules collected from 6 trees. Mating system analysis using MLTR revealed moderate to high outcrossing (t m =0.479-0.806) and low estimates of correlated paternity (r p =0.136±s.e. 0.048). Paternity analysis revealed high outcrossing rates (mean=0.72) and high multiple paternity, with 64 different sires identified for 181 seeds. There was a significant negative relationship between the frequency of outcross mating and distance between mating pairs. Realised mating events were more frequent than expected with random mating for plants <40 m apart. The overall distribution of pollen dispersal distances was platykurtic. Despite extensive pollen dispersal within the stand, three genetic clusters were detected by STRUCTURE analysis. These genetic clusters were strongly differentiated yet geographically interspersed, hypothesised to be a consequence of rare recruitment events coupled with extreme longevity. We suggest that extensive polyandry and pollen dispersal is a consequence of pollination by highly mobile honeyeaters and may buffer E. caesia against the loss of genetic diversity predicted for small and genetically isolated populations.

Paternity analysis reveals wide pollen dispersal and high multiple paternity in a small isolated population of the bird-pollinated Eucalyptus caesia (Myrtaceae)

PubMed Central

Bezemer, N; Krauss, S L; Phillips, R D; Roberts, D G; Hopper, S D

2016-01-01

Optimal foraging behaviour by nectavores is expected to result in a leptokurtic pollen dispersal distribution and predominantly near-neighbour mating. However, complex social interactions among nectarivorous birds may result in different mating patterns to those typically observed in insect-pollinated plants. Mating system, realised pollen dispersal and spatial genetic structure were examined in the bird-pollinated Eucalyptus caesia, a species characterised by small, geographically disjunct populations. Nine microsatellite markers were used to genotype an entire adult stand and 181 seeds from 28 capsules collected from 6 trees. Mating system analysis using MLTR revealed moderate to high outcrossing (tm=0.479–0.806) and low estimates of correlated paternity (rp=0.136±s.e. 0.048). Paternity analysis revealed high outcrossing rates (mean=0.72) and high multiple paternity, with 64 different sires identified for 181 seeds. There was a significant negative relationship between the frequency of outcross mating and distance between mating pairs. Realised mating events were more frequent than expected with random mating for plants <40 m apart. The overall distribution of pollen dispersal distances was platykurtic. Despite extensive pollen dispersal within the stand, three genetic clusters were detected by STRUCTURE analysis. These genetic clusters were strongly differentiated yet geographically interspersed, hypothesised to be a consequence of rare recruitment events coupled with extreme longevity. We suggest that extensive polyandry and pollen dispersal is a consequence of pollination by highly mobile honeyeaters and may buffer E. caesia against the loss of genetic diversity predicted for small and genetically isolated populations. PMID:27530908

Dispersal, mating events and fine-scale genetic structure in the lesser flat-headed bats.

PubMed

Hua, Panyu; Zhang, Libiao; Guo, Tingting; Flanders, Jon; Zhang, Shuyi

2013-01-01

Population genetic structure has important consequences in evolutionary processes and conservation genetics in animals. Fine-scale population genetic structure depends on the pattern of landscape, the permanent movement of individuals, and the dispersal of their genes during temporary mating events. The lesser flat-headed bat (Tylonycteris pachypus) is a nonmigratory Asian bat species that roosts in small groups within the internodes of bamboo stems and the habitats are fragmented. Our previous parentage analyses revealed considerable extra-group mating in this species. To assess the spatial limits and sex-biased nature of gene flow in the same population, we used 20 microsatellite loci and mtDNA sequencing of the ND2 gene to quantify genetic structure among 54 groups of adult flat-headed bats, at nine localities in South China. AMOVA and F(ST) estimates revealed significant genetic differentiation among localities. Alternatively, the pairwise F(ST) values among roosting groups appeared to be related to the incidence of associated extra-group breeding, suggesting the impact of mating events on fine-scale genetic structure. Global spatial autocorrelation analyses showed positive genetic correlation for up to 3 km, indicating the role of fragmented habitat and the specialized social organization as a barrier in the movement of individuals among bamboo forests. The male-biased dispersal pattern resulted in weaker spatial genetic structure between localities among males than among females, and fine-scale analyses supported that relatedness levels within internodes were higher among females than among males. Finally, only females were more related to their same sex roost mates than to individuals from neighbouring roosts, suggestive of natal philopatry in females.

The dynamics of male brooding, mating patterns, and sex roles in pipefishes and seahorses (family Syngnathidae).

PubMed

Wilson, Anthony B; Ahnesjö, Ingrid; Vincent, Amanda C J; Meyer, Axel

2003-06-01

Modern theory predicts that relative parental investment of the sexes in their young is a key factor responsible for sexual selection. Seahorses and pipefishes (family Syngnathidae) are extraordinary among fishes in their remarkable adaptations for paternal care and frequent occurrences of sex-role reversals (i.e., female-female competition for mates), offering exceptional opportunities to test predictions of sexual selection theory. During mating, the female transfers eggs into or onto specialized egg-brooding structures that are located on either the male's abdomen or its tail, where they are osmoregulated, aerated, and nourished by specially adapted structures. All syngnathid males exhibit this form of parental care but the brooding structures vary, ranging from the simple ventral gluing areas of some pipefishes to the completely enclosed pouches found in seahorses. We present a molecular phylogeny that indicates that the diversification of pouch types is positively correlated with the major evolutionary radiation of the group, suggesting that this extreme development and diversification of paternal care may have been an important evolutionary innovation of the Syngnathidae. Based on recent studies that show that the complexity of brooding structures reflects the degree of paternal investment in several syngnathid species, we predicted sex-role reversals to be more common among species with more complex brooding structures. In contrast to this prediction, however, both parsimony- and likelihood-based reconstructions of the evolution of sex-role reversal in pipefishes and seahorses suggest multiple shifts in sex roles in the group, independent from the degree of brood pouch development. At the same time, our data demonstrate that sex-role reversal is positively associated with polygamous mating patterns, whereas most nonreversed species mate monogamously, suggesting that selection for polygamy or monogamy in pipefishes and seahorses may strongly influence sex roles in the wild.

Inbreeding in Gredos mountain range (Spain): contribution of multiple consanguinity and intervalley variation.

PubMed

Fuster, V; Jiménez, A M; Colantonio, S E

2001-04-01

The present paper examines consanguineous marriages occurring between 1874 and 1975 in three valleys (Tormes, Alberche, and Tiétar) in the Sierra de Gredos mountain range, Avila province, Spain. Information was obtained from parish registers of 42 localities, corresponding to a total of 41,696 weddings. Consanguineous marriages were defined as those up to the third degree of consanguinity (second cousins). From 1874 to 1975 the percentage of related mates was 4.45% and the inbreeding coefficient was 0.0011868 (for 1874 to 1917 corresponding figures up to the fourth degree were 16.44% and 0.00 19085, respectively). In order to ascertain the characteristics and evolution of mating patterns in Gredos, the contribution of each degree of kinship was analyzed as a whole and then for each valley separately. Regarding total consanguineous marriages in Gredos, there is a low frequency of uncle-niece matings (0.21%) and a first-second cousin mating ratio (C22/C33) of 0.23 (up to the third degree of consanguinity). Before 1918 multiple matings (i.e., those involving more than a single relationship) accounted for 19.16% of consanguineous marriages (up to the fourth degree). The observed frequencies of multiple consanguineous marriages was, on average, about twice that expected at random, and the proportion of such marriages to total inbreeding was 34.65%. The temporal change of the Gredos inbreeding pattern was characterized by a recent decrease; the highest inbreeding levels correspond to the period from 1915 to 1944. Finally, intervalley differences (maximum inbreeding coefficient in the Tormes, minimum in the Tiétar) are interpreted considering the geography, population size, and population mobility for each valley

Short term, repeated exposure to rams during the transition into the breeding season improves the synchrony of mating in the breeding season.

PubMed

Hawken, P A R; Evans, A C O; Beard, A P

2008-07-01

The ram effect is widely used in Mediterranean breeds of sheep but its use in temperate genotypes is restricted by breed seasonality. However, ewes from these highly seasonal genotypes are sensitive to stimulation by rams close to the onset of the natural breeding season. In this study we developed a pre-mating protocol of repeated, short-term exposure to rams (fence-line contact or vasectomised rams) beginning during late anoestrus and continuing into the breeding season. We hypothesised that this pre-mating protocol would synchronise the distribution of mating of North of England Mule ewes during the breeding season above that observed in ewes isolated from rams prior to mating. Ram-exposed ewes were given contact with rams (Experiment 1: fence-line; FR, n=94 and Experiment 2: vasectomised rams; VR; n=103) for 24h on Days 0 (10 September), 17 and 34 of the experiment. Control ewes (Experiment 1; FC, n=98 and Experiment 2; VC; n=106) remained isolated from rams prior to mating. In Experiment 2, a subset of VR (n=35) and VC ewes (n=35) were blood sampled twice weekly to monitor their pre-mating progesterone profiles. At mating, harnessed entire rams were introduced, 17 or 16 days after the last ram exposure (Experiments 1 and 2) and raddle marks were recorded daily. The median time from ram introduction to mating was reduced in ewes given both fence-line and vasectomised ram contact (P<0.001), leading to a more compact distribution of mating and lambing (At least P<0.01). In the blood sampled VR ewes, there was a progressive decline in the number of days from ram exposure to the onset of dioestrus (at least P<0.05). This observation indicates that the cycles in VR ewes became increasingly synchronised over the pre-mating period, a pattern not evident in VC ewes. In conclusion, repeated, short-term exposure of ewes to rams during the transition into the breeding season is an effective method of synchronising the distribution of mating during the breeding season.

Neural correlates of frog calling: production by two semi-independent generators.

PubMed

Schmidt, R S

1992-09-28

The anterior preoptic nuclei of the isolated brainstem of male, Northern leopard frogs (Rana p. pipiens) were stimulated electrically and neural correlates of mating calling recorded from the rhombencephalic mating calling pattern generator. Lesions of discrete areas of the brainstem showed that the mating calling generator is separable into two generators, the pretrigeminal nucleus and the classical pulmonary respiration generator (which is approximately co-extensive with the motor nuclei IX-X). Each of these still can produce pulses when isolated from the other. Their interaction changes the expiratory phase of breathing into the vocal phase of calling. All stages of intermediates between these phases could be seen. An updated and simplified model of call production and evolution is presented.

The eunuch phenomenon: adaptive evolution of genital emasculation in sexually dimorphic spiders.

PubMed

Kuntner, Matjaž; Agnarsson, Ingi; Li, Daiqin

2015-02-01

Under natural and sexual selection traits often evolve that secure paternity or maternity through self-sacrifice to predators, rivals, offspring, or partners. Emasculation-males removing their genitals-is an unusual example of such behaviours. Known only in insects and spiders, the phenomenon's adaptiveness is difficult to explain, yet its repeated origins and association with sexual size dimorphism (SSD) and sexual cannibalism suggest an adaptive significance. In spiders, emasculation of paired male sperm-transferring organs - secondary genitals - (hereafter, palps), results in 'eunuchs'. This behaviour has been hypothesized to be adaptive because (i) males plug female genitals with their severed palps (plugging hypothesis), (ii) males remove their palps to become better fighters in male-male contests (better-fighter hypothesis), perhaps reaching higher agility due to reduced total body mass (gloves-off hypothesis), and (iii) males achieve prolonged sperm transfer through severed genitals (remote-copulation hypothesis). Prior research has provided evidence in support of these hypotheses in some orb-weaving spiders but these explanations are far from general. Seeking broad macroevolutionary patterns of spider emasculation, we review the known occurrences, weigh the evidence in support of the hypotheses in each known case, and redefine more precisely the particular cases of emasculation depending on its timing in relation to maturation and mating: 'pre-maturation', 'mating', and 'post-mating'. We use a genus-level spider phylogeny to explore emasculation evolution and to investigate potential evolutionary linkage between emasculation, SSD, lesser genital damage (embolic breakage), and sexual cannibalism (females consuming their mates). We find a complex pattern of spider emasculation evolution, all cases confined to Araneoidea: emasculation evolved at least five and up to 11 times, was lost at least four times, and became further modified at least once. We also find emasculation, as well as lesser genital damage and sexual cannibalism, to be significantly associated with SSD. These behavioural and morphological traits thus likely co-evolve in spiders. Emasculation can be seen as an extreme form of genital mutilation, or even a terminal investment strategy linked to the evolution of monogyny. However, as different emasculation cases in araneoid spiders are neither homologous nor biologically identical, and may or may not serve as paternity protection, the direct link to monogyny is not clear cut. Understanding better the phylogenetic patterns of emasculation and its constituent morphologies and behaviours, a clearer picture of the intricate interplay of natural and sexual selection may arise. With the here improved evolutionary resolution of spider eunuch behaviour, we can more specifically tie the evidence from adaptive hypotheses to independent cases, and propose promising avenues for further research of spider eunuchs, and of the evolution of monogyny. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical Society.

Not Only Single Mating in Stingless Bees

NASA Astrophysics Data System (ADS)

Paxton, Robert J.; Weißschuh, Nicole; Engels, Wolf; Hartfelder, Klaus; Quezada-Euan, J. Javier G.

Queens of the large, pantropical and fully eusocial taxon Meliponinae (stingless bees) are generally considered to be singly mated. We indirectly estimated queen mating frequency in two meliponids, Melipona beecheii and Scaptotrigona postica, by examining genotypes of workers at microsatellite DNA loci. Microsatellites were highly variable, providing suitable markers with which to assign patrilinial origin of workers within colonies headed by single queens. Queen mating frequency varied between 1 and 3 (M. beecheii) and 1 and 6 (S. postica), representing the first clear documentation of polyandry in the Meliponinae. Effective paternity frequency, me, was lower, although above 2 for S. postica. Stingless bees may provide suitable subjects for the testing of recent inclusive fitness arguments describing intracolony kin conflict in social Hymenoptera.

Mating Plugs in Polyandrous Giants: Which Sex Produces Them, When, How and Why?

PubMed Central

Kuntner, Matjaž; Kralj-Fišer, Simona; Li, Daiqin

2012-01-01

Background Males usually produce mating plugs to reduce sperm competition. However, females can conceivably also produce mating plugs in order to prevent unwanted, superfluous and energetically costly matings. In spiders–appropriate models for testing plugging biology hypotheses–mating plugs may consist of male genital parts and/or of amorphous covers consisting of glandular or sperm secretions. In the giant wood spider Nephila pilipes, a highly sexually dimorphic and polygamous species, males are known to produce ineffective embolic plugs through genital damage, but nothing is known about the origin and function of additional conspicuous amorphous plugs (AP) covering female genitals. Methodology We tested alternative hypotheses of the nature and function of AP in N. pilipes by staging mating trials with varying degrees of polyandry. No APs were ever formed during mating trials, which rules out the possibility of male AP formation. Instead, those females that oviposited produced the AP from a liquid secreted during egg sac formation. Polyandrous females were more likely to lay eggs and to produce the AP, as were those that mated longer and with more total insertions. Our further tests revealed that, in spite of being a side product of egg sac production, AP, when hardened, prevented any subsequent copulation. Conclusions We conclude that in the giant wood spider (Nephila pilipes), the amorphous mating plugs are not produced by the males, that repeated copulations (most likely polyandrous) are necessary for egg fertilization and AP formation, and that the AP represents a female adaptation to sexual conflict through prevention of unwanted, excessive copulations. Considering the largely unknown origin of amorphous plugs in spiders, we predict that a similar pattern might be detected in other clades, which would help elucidate the evolutionary interplay of various selection pressures responsible for the origin and maintenance of mating plugs. PMID:22829900

Evolution of uni- and bifactorial sexual compatibility systems in fungi

PubMed Central

Nieuwenhuis, B P S; Billiard, S; Vuilleumier, S; Petit, E; Hood, M E; Giraud, T

2013-01-01

Mating systems, that is, whether organisms give rise to progeny by selfing, inbreeding or outcrossing, strongly affect important ecological and evolutionary processes. Large variations in mating systems exist in fungi, allowing the study of their origin and consequences. In fungi, sexual incompatibility is determined by molecular recognition mechanisms, controlled by a single mating-type locus in most unifactorial fungi. In Basidiomycete fungi, however, which include rusts, smuts and mushrooms, a system has evolved in which incompatibility is controlled by two unlinked loci. This bifactorial system probably evolved from a unifactorial system. Multiple independent transitions back to a unifactorial system occurred. It is still unclear what force drove evolution and maintenance of these contrasting inheritance patterns that determine mating compatibility. Here, we give an overview of the evolutionary factors that might have driven the evolution of bifactoriality from a unifactorial system and the transitions back to unifactoriality. Bifactoriality most likely evolved for selfing avoidance. Subsequently, multiallelism at mating-type loci evolved through negative frequency-dependent selection by increasing the chance to find a compatible mate. Unifactoriality then evolved back in some species, possibly because either selfing was favoured or for increasing the chance to find a compatible mate in species with few alleles. Owing to the existence of closely related unifactorial and bifactorial species and the increasing knowledge of the genetic systems of the different mechanisms, Basidiomycetes provide an excellent model for studying the different forces that shape breeding systems. PMID:23838688

Mixed messages: wild female bonobos show high variability in the timing of ovulation in relation to sexual swelling patterns.

PubMed

Douglas, Pamela Heidi; Hohmann, Gottfried; Murtagh, Róisín; Thiessen-Bock, Robyn; Deschner, Tobias

2016-06-30

The evolution of primate sexual swellings and their influence on mating strategies have captivated the interest of biologists for over a century. Across the primate order, variability in the timing of ovulation with respect to females' sexual swelling patterns differs greatly. Since sexual swellings typically function as signals of female fecundity, the temporal relation between ovulation and sexual swellings can impact the ability of males to pinpoint ovulation and thereby affect male mating strategies. Here, we used endocrine parameters to detect ovulation and examined the temporal relation between the maximum swelling phase (MSP) and ovulation in wild female bonobos (Pan paniscus). Data were collected at the Luikotale field site, Democratic Republic of Congo, spanning 36 months. Observational data from 13 females were used to characterise female swelling cycles (N = 70). Furthermore, we measured urinary oestrone and pregnanediol using liquid chromatography-tandem mass spectrometry, and used pregnanediol to determine the timing of ovulation in 34 cycles (N = 9 females). We found that the duration of females' MSP was highly variable, ranging from 1 to 31 days. Timing of ovulation varied considerably in relation to the onset of the MSP, resulting in a very low day-specific probability of ovulation and fecundity across female cycles. Ovulation occurred during the MSP in only 52.9 % of the analysed swelling cycles, and females showed regular sexual swelling patterns in N = 8 swelling cycles where ovulation did not occur. These findings reveal that sexual swellings of bonobos are less reliable indicators of ovulation compared to other species of primates. Female bonobos show unusual variability in the duration of the MSP and in the timing of ovulation relative to the sexual swelling signal. These data are important for understanding the evolution of sexual signals, how they influence male and female mating strategies, and how decoupling visual signals of fecundity from the periovulatory period may affect intersexual conflict. By prolonging the period during which males would need to mate guard females to ascertain paternity, the temporal variability of this signal may constrain mate-guarding efforts by male bonobos.

Female Choice or Male Sex Drive? The Advantages of Male Body Size during Mating in Drosophila Melanogaster.

PubMed

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.

Chimpanzees breed with genetically dissimilar mates

PubMed Central

Rudicell, Rebecca S.; Li, Yingying; Hahn, Beatrice H.; Wroblewski, Emily; Pusey, Anne E.

2017-01-01

Inbreeding adversely affects fitness, whereas heterozygosity often augments it. Therefore, mechanisms to avoid inbreeding and increase genetic distance between mates should be advantageous in species where adult relatives reside together. Here we investigate mate choice for genetic dissimilarity in chimpanzees, a species in which many females avoid inbreeding through dispersal, but where promiscuous mating and sexual coercion can limit choice when related adults reside together. We take advantage of incomplete female dispersal in Gombe National Park, Tanzania to compare mate choice for genetic dissimilarity among immigrant and natal females in two communities using pairwise relatedness measures in 135 genotyped chimpanzees. As expected, natal females were more related to adult males in their community than were immigrant females. However, among 62 breeding events, natal females were not more related to the sires of their offspring than immigrant females, despite four instances of close inbreeding. Moreover, females were generally less related to the sires of their offspring than to non-sires. These results demonstrate that chimpanzees may be capable of detecting relatedness and selecting mates on the basis of genetic distance. PMID:28280546

Chimpanzees breed with genetically dissimilar mates.

PubMed

Walker, Kara K; Rudicell, Rebecca S; Li, Yingying; Hahn, Beatrice H; Wroblewski, Emily; Pusey, Anne E

2017-01-01

Inbreeding adversely affects fitness, whereas heterozygosity often augments it. Therefore, mechanisms to avoid inbreeding and increase genetic distance between mates should be advantageous in species where adult relatives reside together. Here we investigate mate choice for genetic dissimilarity in chimpanzees, a species in which many females avoid inbreeding through dispersal, but where promiscuous mating and sexual coercion can limit choice when related adults reside together. We take advantage of incomplete female dispersal in Gombe National Park, Tanzania to compare mate choice for genetic dissimilarity among immigrant and natal females in two communities using pairwise relatedness measures in 135 genotyped chimpanzees. As expected, natal females were more related to adult males in their community than were immigrant females. However, among 62 breeding events, natal females were not more related to the sires of their offspring than immigrant females, despite four instances of close inbreeding. Moreover, females were generally less related to the sires of their offspring than to non-sires. These results demonstrate that chimpanzees may be capable of detecting relatedness and selecting mates on the basis of genetic distance.

Icebox, a recessive X-linked mutation in Drosophila causing low sexual receptivity.

PubMed

Kerr, C; Ringo, J; Dowse, H; Johnson, E

1997-11-01

The X-linked recessive mutation icebox (ibx; 1-23, 7F1) of Drosophila melanogaster lowers the sexual receptivity of females. The probability of mating with mature wild-type males is reduced in ibx homozygotes, and the frequency of rejection behavior (rate per minute) towards courting males is increased. ibx fails to complement In(1)RA35, which is a lethal allele of Neuroglian (Nrg, which encodes a transmembrane protein found in embryonic tissues including the nervous system) due to a breakpoint in that gene; however, both l(1)B4 and l(1)VA142, other lethal mutations of Nrg, do complement ibx. 12-h ibx embryos exhibit a normal pattern of staining for the Neuroglian-specific antibody, Mab BP104. Males and females mutant for ibx have normal egg-to-adult survival and appear normal in several "general" behavioral traits including olfaction, phototaxis, locomotor activity, and heartbeat. ibx males court normally, and are successful in mating. These characteristics suggest that ibx does not cause sensory or motor defects. Ovarian growth and sperm storage are wild-type in ibx/ibx females. Treatment with the JH analog methoprene increases the receptivity of ibx/ibx females.

Mating tactics determine patterns of condition dependence in a dimorphic horned beetle.

PubMed

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.

A longitudinal study of the sociosexual dynamics in a captive family group of wolves: the University of Connecticut wolf project.

PubMed

Jenks, Susan M

2011-11-01

An interest in the role of the social environment on the evolution of behavior led Professor Benson Ginsburg to studies of wolf social behavior. He initiated the University of Connecticut wolf project with a family group of wolves housed in a protected enclosure in an isolated area of campus. One aim of this project was to conduct a longitudinal study of a family group of wolves in order to understand the proximate behavioral mechanisms underlying mating dynamics with a degree of control and opportunistic observation that could not be achieved through field studies. The development of social relationships and the dynamics of mating were observed for 9 years. As in nature, agonistic relationships strongly influenced reproductive success, successful breeding was limited to a single pair each season, and the behavioral dynamics included status transitions with breeder rotations. Our work, when combined with the results of other captive wolf studies, has contributed valuable information to the general understanding of wolf social behavior, especially regarding the proximate behavior patterns underlying group social interactions and reproduction. This understanding has broadened perspectives on the dynamic interplay between social behavior and evolutionary processes.

Evolution of fungal sexual reproduction.

PubMed

Heitman, Joseph; Sun, Sheng; James, Timothy Y

2013-01-01

We review here recent advances in our understanding of the genetic, molecular and genomic basis of sex determination and sexual reproduction in the fungal kingdom as a window on the evolution of sex in eukaryotes more generally. In particular, we focus on the evolution of the mating-type locus and transitions in modes of sexual reproduction using examples from throughout the kingdom. These examples illustrate general principles of the origins of mating-type loci/sex chromosomes and the balance between inbreeding and outcrossing afforded by different modes of sexual reproduction involving tetrapolar, bipolar and unipolar sexual cycles.

Geography, assortative mating, and the effects of sexual selection on speciation with gene flow.

PubMed

Servedio, Maria R

2016-01-01

Theoretical and empirical research on the evolution of reproductive isolation have both indicated that the effects of sexual selection on speciation with gene flow are quite complex. As part of this special issue on the contributions of women to basic and applied evolutionary biology, I discuss my work on this question in the context of a broader assessment of the patterns of sexual selection that lead to, versus inhibit, the speciation process, as derived from theoretical research. In particular, I focus on how two factors, the geographic context of speciation and the mechanism leading to assortative mating, interact to alter the effect that sexual selection through mate choice has on speciation. I concentrate on two geographic contexts: sympatry and secondary contact between two geographically separated populations that are exchanging migrants and two mechanisms of assortative mating: phenotype matching and separate preferences and traits. I show that both of these factors must be considered for the effects of sexual selection on speciation to be inferred.

Armed Service Vocational Aptitude Battery Scores and Aviation Electrician's Mate Class "A" School Attrition Rate.

ERIC Educational Resources Information Center

Miller, Hershel M.

A study investigated the use of the Armed Services Vocational Aptitude Battery (ASVAB) subtests and combinations of subtest composites as placement qualifiers for the Aviation Electrician's Mate AEA(A1) school. It examined the relationship of the independent variables Arithmetic Reasoning; Math Knowledge; General Science; and Composite ASVAB score…

Parental care improves immunity in the seahorse (Hippocampus erectus).

PubMed

Lin, Tingting; Zhang, Dong; Liu, Xin; Xiao, Dongxue

2016-11-01

In the present study, the sexual dimorphism in immune response in the seahorse Hippocampus erectus in which males compete for mates and invest heavily in parental care was assessed. Variability in immunocompetence in virginal seahorses with differing levels of sexual maturity (i.e., immaturity, early maturity and maturity) and with different mating statuses (i.e., virginal, experienced mating failure and experienced mating success) were analyzed by evaluating immune parameters in the plasma. Additionally, ultrastructural characteristics of the inner epithelium of the brood pouch were compared between males that had experienced mating failure and those that had succeeded. Generally, immunity in sexually mature virgin males was greater than in females, and mating competition significantly reduced males' immunity. However, parental care gave males stronger immune and metabolic abilities and resulted in their immunity significantly rebounding after a successful mating. The present study quantitatively clarifies, for the first time, how parental care and mating competition jointly affect immunity. Moreover, previous findings that females display more efficient immune defenses than males in conventional species (i.e., males are as competitor and females as care giver) and that males' immunity is higher than females' in the pipefish (i.e., females are as competitor and males as care giver) in combination with the present results indicate that parental care is a key factor for sexual dimorphism in immunity. The care-giving sex has strong immunity regardless of the sex in charge of mating competition or not. Copyright © 2016 Elsevier Ltd. All rights reserved.

Non-random mate choice in humans: insights from a genome scan.

PubMed

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.

Selection on an antagonistic behavioral trait can drive rapid genital coevolution in the burying beetle, Nicrophorus vespilloides

PubMed Central

Hopwood, Paul E.; Head, Megan L.; Jordan, Eleanor J.; Carter, Mauricio J.; Davey, Emma; Moore, Allen J.; Royle, Nick J.

2016-01-01

Male and female genital morphology varies widely across many taxa, and even among populations. Disentangling potential sources of selection on genital morphology is problematic because each sex is predicted to respond to adaptations in the other due to reproductive conflicts of interest. To test how variation in this sexual conflict trait relates to variation in genital morphology we used our previously developed artificial selection lines for high and low repeated mating rates. We selected for high and low repeated mating rates using monogamous pairings to eliminate contemporaneous female choice and male–male competition. Male and female genital shape responded rapidly to selection on repeated mating rate. High and low mating rate lines diverged from control lines after only 10 generations of selection. We also detected significant patterns of male and female genital shape coevolution among selection regimes. We argue that because our selection lines differ in sexual conflict, these results support the hypothesis that sexually antagonistic coevolution can drive the rapid divergence of genital morphology. The greatest divergence in morphology corresponded with lines in which the resolution of sexual conflict over mating rate was biased in favor of male interests. PMID:27144373

Parental conflict in birds: comparative analyses of offspring development, ecology and mating opportunities

PubMed Central

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

Population genetics of sporophytic self-incompatibility in Senecio squalidus L. (Asteraceae) II: a spatial autocorrelation approach to determining mating behaviour in the presence of low S allele diversity.

PubMed

Brennan, A C; Harris, S A; Hiscock, S J

2003-11-01

We recently estimated that as few as six S alleles represent the extent of S locus diversity in a British population of the self-incompatible (SI) coloniser Senecio squalidus (Oxford Ragwort). Despite the predicted constraints to mating imposed by such a low number of S alleles, S. squalidus maintains a strong sporophytic self-incompatibility (SSI) system and there is no evidence for a breakdown of SSI or any obvious negative reproductive consequences for this highly successful coloniser. The present paper assesses mating behaviour in an Oxford S. squalidus population through observations of its effect on spatial patterns of genetic diversity and thus the extent to which it is responsible for ameliorating the potentially detrimental reproductive consequences of low S allele diversity in British S. squalidus. A spatial autocorrelation (SA) treatment of S locus and allozyme polymorphism data for four loci indicates that mating events regularly occur at all the distance classes examined from 60 to 480 m throughout the entire sample population. Less SA is observed for S locus data than for allozyme data in accordance with the hypothesis that SSI and low diversity at the S locus are driving these large-scale mating events. The limited population structure at small distances of 60 m and less observed for SA analysis of the Me-2 locus and by F-statistics for all the allozyme data, is evidence of some local relatedness due to limited seed and pollen dispersal in S. squalidus. However, the overall impression of mating dynamics in this S. squalidus population is that of ample potential mating opportunities with many individuals at large population scales, indicating that reproductive success is not seriously affected by few S alleles available for mating interactions.

All God's Chillun Got a Mama and a Papa?

ERIC Educational Resources Information Center

Hollander, Willard F.

1972-01-01

Describes alternate methods of schematically representing genetic lines of descent, and illustrates the different patterns obtained with random mating, line breeding, parthanogentic males, cloning, and grafting. (AL)

Integrating Competition for Food, Hosts, or Mates via Experimental Evolution.

PubMed

Rodrigues, Leonor R; Duncan, Alison B; Clemente, Salomé H; Moya-Laraño, Jordi; Magalhães, Sara

2016-02-01

Competitive interactions shape the evolution of organisms. However, often it is not clear whether competition is the driving force behind the patterns observed. The recent use of experimental evolution in competitive environments can help establish such causality. Unfortunately, this literature is scattered, as competition for food, mates, and hosts are subject areas that belong to different research fields. Here, we group these bodies of literature, extract common processes and patterns concerning the role of competition in shaping evolutionary trajectories, and suggest perspectives stemming from an integrative view of competition across these research fields. This review reinstates the power of experimental evolution in addressing the evolutionary consequences of competition, but highlights potential pitfalls in the design of such experiments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Discrimination of face-like patterns in the giant panda (Ailuropoda melanoleuca).

PubMed

Dungl, Eveline; Schratter, Dagmar; Huber, Ludwig

2008-11-01

The black-and-white pattern of the giant panda's (Ailuropoda melanoleuca) fur is a conspicuous signal and may be used for mate-choice and intraspecific communication. Here the authors examined whether they have the perceptual and cognitive potential to make use of this information. Two juvenile subjects were trained on several discrimination problems in steps of increasing difficulty, whereby the stimuli required to discriminate ranged from geometric figures to pairs of differently orientated ellipses, pairs of ellipses with the same orientation but different angles, and finally discrimination of panda-like eye-mask patterns that differed only subtly in shape. Not only did both subjects achieve significant levels of discrimination in all these tasks, they also remembered discriminations for 6 months or even 1 year after the first presentation. Thus this study provided the first solid evidence of sufficient visual and cognitive potential in the giant panda to use the fur pattern or the facial masks for individual recognition, social communication, and perhaps, mate choice. (PsycINFO Database Record (c) 2008 APA, all rights reserved).

An introgressed wing pattern acts as a mating cue.

PubMed

Sánchez, Angela P; Pardo-Diaz, Carolina; Enciso-Romero, Juan; Muñoz, Astrid; Jiggins, Chris D; Salazar, Camilo; Linares, Mauricio

2015-06-01

Heliconius butterflies provide good examples of both homoploid hybrid speciation and ecological speciation. In particular, examples of adaptive introgression have been detected among the subspecies of Heliconius timareta, which acquired red color pattern elements from H. melpomene. We tested whether the introgression of red wing pattern elements into H. timareta florencia might also be associated with incipient reproductive isolation (RI) from its close relative, H. timareta subsp. nov., found in the eastern Andes. No choice experiments show a 50% reduction in mating between females of H. t. subsp. nov. and males of H .t. florencia, but not in the reciprocal direction. In choice experiments using wing models, males of H. timareta subsp. nov. approach and court red phenotypes less than their own, whereas males of H. t. florencia prefer models with a red phenotype. Intrinsic postzygotic isolation was not detected in crosses between these H. timareta races. These results suggest that a color pattern trait gained by introgression is triggering RI between H. timareta subsp. nov. and H. t. florencia. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Is incest common in gray wolf packs?

USGS Publications Warehouse

Smith, Deborah E; Meier, Thomas J.; Geffen, Eli; Mech, L. David; Burch, John W.; Adams, Layne G.; Wayne, Robert K.

1997-01-01

Wolf packs generally consist of a breeding pair and their maturing offspring that help provision and protect pack young. Because the reproductive tenure in wolves is often short, reproductively mature offspring might replace their parents, resulting in sibling or parent-offspring matings. To determine the extent of incestuous pairings, we measured relatedness based on variability in 20 microsatellite loci of mated pairs, parent-offspring pairs, and siblings in two populations of gray wolves. Our 16 sampled mated pairs had values of relatedness not overlapping those of known parent-offspring or sibling dyads, which is consistent with their being unrelated or distantly related. These results suggest that full siblings or a parent and its offspring rarely mate and that incest avoidance is an important constraint on gray wolf behavioral ecology.

Reproductive performance of cows mated to and preweaning performance of calves sired by Brahman vs alternative subtropically adapted breeds.

PubMed

Thrift, F A

1997-10-01

Comparisons involving Brahman and Brahman-derivative (Brangus, Santa Gertrudis, Beef-master, Simbrah, Braford) sires indicate the following: 1) cows mated to Brangus and Santa Gertrudis bulls had a shorter gestation length than cows mated to Brahman bulls, 2) calves sired by Brangus and Beefmaster bulls were lighter at birth and weaning than calves sired by Brahman bulls, and 3) birth and weaning weights were similar for calves sired by Santa Gertrudis and Brahman bulls and for calves sired by Simbrah and Brahman bulls. Comparisons involving Brahman and other Zebu (Sahiwal, Nellore, Gir, Indu-Brazil, Boran, Romana Red) sires indicate that gestation length was slightly longer for cows mated to Sahiwal and Nellore bulls and that, relative to the Brahman, birth and weaning weights were similar to or lighter for calves sired by bulls of the other Zebu breeds. The only exception to this pattern was birth weight of Indu-Brazil-sired calves, which were heavier than calves sired by Brahman bulls. Comparisons involving Brahman and non-Zebu subtropically adapted (Tuli, Senepol) sires indicate that cows mated to Tuli bulls had a slightly shorter gestation length than cows mated to Brahman bulls and that birth and weaning weights of calves sired by Tuli and Senepol bulls were lighter than those of calves sired by Brahman bulls.

Development of programmable artificial neural networks

NASA Technical Reports Server (NTRS)

Meade, Andrew J.

1993-01-01

Conventionally programmed digital computers can process numbers with great speed and precision, but do not easily recognize patterns or imprecise or contradictory data. Instead of being programmed in the conventional sense, artificial neural networks are capable of self-learning through exposure to repeated examples. However, the training of an ANN can be a time consuming and unpredictable process. A general method is being developed to mate the adaptability of the ANN with the speed and precision of the digital computer. This method was successful in building feedforward networks that can approximate functions and their partial derivatives from examples in a single iteration. The general method also allows the formation of feedforward networks that can approximate the solution to nonlinear ordinary and partial differential equations to desired accuracy without the need of examples. It is believed that continued research will produce artificial neural networks that can be used with confidence in practical scientific computing and engineering applications.

Mate attraction, retention and expulsion.

PubMed

Miner, Emily J; Shackelford, Todd K

2010-02-01

Sexual selection theory and parental investment theory have guided much of the evolutionary psychological research on human mating. Based on these theories, researchers have predicted and found sex differences in mating preferences and behaviors. Men generally prefer that their long-term partners are youthful and physically attractive. Women generally prefer that their long-term partners have existing resources or clear potential for securing resources and display a willingness to invest those resources in children the relationship might produce. Both men and women, however, desire long-term partners who are kind and intelligent. Once a partner is obtained, men and women act in sex-specific ways to ensure the continuation and exclusivity of the relationship. Men, in particular, engage in behaviors designed to prevent, correct, and anticipate their partner's sexual infidelity. Relationships dissolve for evolutionarily-relevant reasons: infidelity, childlessness, and infertility. The discussion addresses directions for future research.

Is male rhesus macaque red color ornamentation attractive to females?

PubMed Central

Dubuc, Constance; Allen, William L.; Maestripieri, Dario; Higham, James P.

2014-01-01

Male sexually-selected traits can evolve through different mechanisms: conspicuous and colorful ornaments usually evolve through inter-sexual selection, while weapons usually evolve through intra-sexual selection. Male ornaments are rare among mammals in comparison to birds, leading to the notion that female mate choice generally plays little role in trait evolution in this taxon. Supporting this view, when ornaments are present in mammals they typically indicate social status and are products of male-male competition. This general mammalian pattern, however, may not apply to rhesus macaques (Macaca mulatta). Males of this species display conspicuous skin coloration, but this expression is not correlated to dominance rank, and is therefore unlikely to have evolved due to male-male competition. Here, we investigate whether male color expression influences female proceptivity towards males in the Cayo Santiago free-ranging rhesus macaque population. We collected face images of 24 adult males varying in dominance rank and age at the peak of the mating season, and modeled these to rhesus macaque visual perception. We also recorded female socio-sexual behaviors towards these males. Results show that dark red males received more sexual solicitations, by more females, than pale pink ones. Together with previous results, our study suggests that male color ornaments are more likely to be a product of inter- rather than intra-sexual selection. This may especially be the case in rhesus macaques due to the particular characteristics of male-male competition in this species. PMID:25246728

Variation in pre- and post-copulatory sexual selection on male genital size in two species of lygaeid bug.

PubMed

Dougherty, Liam R; Shuker, David M

Sexual selection has been shown to be the driving force behind the evolution of the sometimes extreme and elaborate genitalia of many species. Sexual selection may arise before and/or after mating, or vary according to other factors such as the social environment. However, bouts of selection are typically considered in isolation. We measured the strength and pattern of selection acting on the length of the male intromittent organ (or processus) in two closely related species of lygaeid seed bug: Lygaeus equestris and Lygaeus simulans . In both species, we measured both pre- and post-copulatory selection. For L. equestris , we also varied the experimental choice design used in mating trials. We found contrasting pre- and post-copulatory selection on processus length in L. equestris . Furthermore, significant pre-copulatory selection was only seen in mating trials in which two males were present. This selection likely arises indirectly due to selection on a correlated trait, as the processus does not interact with the female prior to copulation. In contrast, we were unable to detect significant pre- or post-copulatory selection on processus length in L. simulans . However, a formal meta-analysis of previous estimates of post-copulatory selection on processus length in L. simulans suggests that there is significant stabilising selection across studies, but the strength of selection varies between experiments. Our results emphasise that the strength and direction of sexual selection on genital traits may be multifaceted and can vary across studies, social contexts and different stages of reproduction. Animal genitalia vary greatly in size and complexity across species, and selection acting on genital size and shape can be complex. In this study, we show that the length of the penis in two species of seed bug is subject to complex patterns of selection, varying depending on the social context and whether selection is measured before or after mating. In one of the species, we show unexpectedly that penis length is correlated with male mating success, despite the fact that the penis does not interact with the female prior to mating. Our results highlight the fact that genitalia may be subject to both direct and indirect selection at different stages of mating and that to fully understand the evolution of such traits we should combine estimates of selection arising from these multiple episodes.

Female Drosophila melanogaster gene expression and mate choice: the X chromosome harbours candidate genes underlying sexual isolation.

PubMed

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.

QTLs Regulating the Contents of Antioxidants, Phenolics, and Flavonoids in Soybean Seeds Share a Common Genomic Region.

PubMed

Li, Man-Wah; Muñoz, Nacira B; Wong, Chi-Fai; Wong, Fuk-Ling; Wong, Kwong-Sen; Wong, Johanna Wing-Hang; Qi, Xinpeng; Li, Kwan-Pok; Ng, Ming-Sin; Lam, Hon-Ming

2016-01-01

Soybean seeds are a rich source of phenolic compounds, especially isoflavonoids, which are important nutraceuticals. Our study using 14 wild- and 16 cultivated-soybean accessions shows that seeds from cultivated soybeans generally contain lower total antioxidants compared to their wild counterparts, likely an unintended consequence of domestication or human selection. Using a recombinant inbred population resulting from a wild and a cultivated soybean parent and a bin map approach, we have identified an overlapping genomic region containing major quantitative trait loci (QTLs) that regulate the seed contents of total antioxidants, phenolics, and flavonoids. The QTL for seed antioxidant content contains 14 annotated genes based on the Williams 82 reference genome (Gmax1.01). None of these genes encodes functions that are related to the phenylpropanoid pathway of soybean. However, we found three putative Multidrug And Toxic Compound Extrusion (MATE) transporter genes within this QTL and one adjacent to it (GmMATE1-4). Moreover, we have identified non-synonymous changes between GmMATE1 and GmMATE2, and that GmMATE3 encodes an antisense transcript that expresses in pods. Whether the polymorphisms in GmMATE proteins are major determinants of the antioxidant contents, or whether the antisense transcripts of GmMATE3 play important regulatory roles, awaits further functional investigations.

Biogeography predicts macro‐evolutionary patterning of gestural display complexity in a passerine family

PubMed Central

Miles, Meredith C.; Cheng, Samantha; Fuxjager, Matthew J.

2017-01-01

Gestural displays are incorporated into the signaling repertoire of numerous animal species. These displays range from complex signals that involve impressive and challenging maneuvers, to simpler displays or no gesture at all. The factors that drive this evolution remain largely unclear, and we therefore investigate this issue in New World blackbirds by testing how factors related to a species’ geographical distribution and social mating system predict macro‐evolutionary patterns of display elaboration. We report that species inhabiting temperate regions produce more complex displays than species living in tropical regions, and we attribute this to (i) ecological factors that increase the competitiveness of the social environment in temperate regions, and (ii) different evolutionary and geological contexts under which species in temperate and tropical regions evolved. Meanwhile, we find no evidence that social mating system predicts species differences in display complexity, which is consistent with the idea that gestural displays evolve independently of social mating system. Together, these results offer some of the first insight into the role played by geographic factors and evolutionary context in the evolution of the remarkable physical displays of birds and other vertebrates. PMID:28240772

Inferred Paternity and Male Reproductive Success in a Killer Whale (Orcinus orca) Population.

PubMed

Ford, Michael J; Hanson, M Bradley; Hempelmann, Jennifer A; Ayres, Katherine L; Emmons, Candice K; Schorr, Gregory S; Baird, Robin W; Balcomb, Kenneth C; Wasser, Samuel K; Parsons, Kim M; Balcomb-Bartok, Kelly

2011-01-01

We used data from 78 individuals at 26 microsatellite loci to infer parental and sibling relationships within a community of fish-eating ("resident") eastern North Pacific killer whales (Orcinus orca). Paternity analysis involving 15 mother/calf pairs and 8 potential fathers and whole-pedigree analysis of the entire sample produced consistent results. The variance in male reproductive success was greater than expected by chance and similar to that of other aquatic mammals. Although the number of confirmed paternities was small, reproductive success appeared to increase with male age and size. We found no evidence that males from outside this small population sired any of the sampled individuals. In contrast to previous results in a different population, many offspring were the result of matings within the same "pod" (long-term social group). Despite this pattern of breeding within social groups, we found no evidence of offspring produced by matings between close relatives, and the average internal relatedness of individuals was significantly less than expected if mating were random. The population's estimated effective size was <30 or about 1/3 of the current census size. Patterns of allele frequency variation were consistent with a population bottleneck.

Singing behavior of fin whales in the Davis Strait with implications for mating, migration and foraging.

PubMed

Simon, Malene; Stafford, Kathleen M; Beedholm, Kristian; Lee, Craig M; Madsen, Peter T

2010-11-01

Most baleen whales undertake migrations between low-latitude breeding grounds and high-latitude feeding grounds. Though little is known about the timing of their migration from the Arctic, fin whales are assumed to undertake a similar migratory pattern. To address questions about habitat use and migrations, the acoustic activity of fin whales in Davis Strait, between Greenland and Canada, was monitored continuously for two years using three bottom-moored acoustic recorders. The acoustic power in the fin whale call frequencies peaked in November-December, showing that fin whales are present in Davis Strait much later in the year than previously expected. The closely timed peaks in song activity and conception time imply that not all fin whales migrate south to mate, but rather start mating at high latitudes rather than or before migrating. Singing activity was strongly linked to daylight hours, suggesting that fin whales might feed during the few daylight hours of the late fall and early Arctic winter. A negative correlation between the advancing sea ice front and power in fin whale frequencies indicates that future changes in sea ice conditions from global warming might change the distribution and migratory patterns of fin whales near the poles.

Assortative Mating by Education and Hukou in Shanghai

PubMed Central

Qian, Yue; Qian, Zhenchao

2018-01-01

Previous research on Hukou-based stratification mostly focuses on Hukou-derived labor market outcomes, with growing attention paid to the role of Hukou locality (local vs. nonlocal) as an increasingly important agent of social stratification in urban China. Few studies have, however, examined how Hukou shapes the patterns of who marries whom in geographically-defined marriage markets, despite the far-reaching implications of assortative mating for migrant integration into the host society, economic inequality among families, and intergenerational transmissions of social traits. In this paper, using a most recent, representative sample of the post-’80s generation living in Shanghai, we evaluate how Hukou locality intersects with educational attainment to shape assortative marriage patterns. We find that highly-educated Hukou residents and non-Hukou migrants are both more likely than their less-educated counterparts to marry a Hukou resident, suggesting that Shanghai Hukou is a valuable attribute in Shanghai marriage market. In addition, Hukou intermarriage seldom occurs when Hukou residents marry a non-Hukou migrant with less education than themselves. The results indicate that Hukou locality is an important stratifier in contemporary China that shapes marriage market conditions and individual mating choices. PMID:29564190

Beauty is in the efficient coding of the beholder.

PubMed

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.

Does higher education expansion promote educational homogamy? Evidence from married couples of the post-80s generation in Shanghai, China.

PubMed

Hu, Anning; Qian, Zhenchao

2016-11-01

The expansion of higher education witnessed in many societies influences the pattern of educational assortative mating. Structural transition theory predicts growing educational homogamy due to increasing preference for highly-educated partners who become more widely available. In contrast, social closure theory suggests depressed educational homogamy because the inflation of the education elite circle fosters the openness of marriage market, reducing the preference for a highly-educated mate and increasing the penetrability across social-status boundaries. Capitalizing the survey data that are representative of the post-80s one-child generation collected in Shanghai, China, we test the hypotheses derived from the two theories. Empirical results suggest that, with increasing availability of highly educated individuals, the extent of educational homogamy by birth cohort reveals a U-shaped pattern. This U-shaped pattern demonstrates increasing levels of educational homogamy and lends support to structural transition theory. Copyright © 2016 Elsevier Inc. All rights reserved.

Fertilisation and early developmental barriers to hybridisation in field crickets.

PubMed

Tyler, Frances; Rodríguez-Muñoz, Rolando; Tregenza, Tom

2013-02-15

Post-mating interactions between the reproductive traits and gametes of mating individuals and among their genes within zygotes are invariably complex, providing multiple opportunities for reproduction to go awry. These interactions have the potential to act as barriers to gene flow between species, and may be important in the process of speciation. There are multiple post-mating barriers to interbreeding between the hybridising field crickets Gryllus bimaculatus and G. campestris. Female G. bimaculatus preferentially store sperm from conspecific males when mated to both conspecific and heterospecific partners. Additionally, conspecific males sire an even greater proportion of offspring than would be predicted from their sperm's representation in the spermatheca. The nature of these post-sperm-storage barriers to hybridisation are unknown. We use a fluorescent staining technique to determine whether barriers occur prior to, or during embryo development. We show that eggs laid by G. bimaculatus females mated to G. campestris males are less likely to begin embryogenesis than eggs from conspecific mating pairs. Of the eggs that are successfully fertilised and start to develop, those from heterospecific mating pairs are more likely to arrest early, prior to blastoderm formation. We find evidence for bimodal variation among egg clutches in the number of developing embryos that subsequently arrest, indicating that there is genetic variation for incompatibility between mating individuals. In contrast to the pattern of early embryonic mortality, those hybrids reaching advanced stages of embryogenesis have survival rates equal to that of embryos from conspecific mating pairs. Post-sperm-storage barriers to hybridisation show evidence of genetic polymorphism. They are sufficiently large, that if the species interbreed where they are sympatric, these barriers could play a role in the maintenance of reproductive isolation between them. The number of eggs that fail to develop represents a substantial cost of hybridization to G. bimaculatus females, and this cost could reinforce the evolution of barriers occurring earlier in the reproductive process.

Mate choice for genetic compatibility in the house mouse

PubMed Central

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

Terminal Investment Strategies and Male Mate choice: Extreme Tests of Bateman.

PubMed

Andrade, Maydianne C B; Kasumovic, Michael M

2005-11-01

Bateman's principle predicts the intensity of sexual selection depends on rates of increase of fecundity with mating success for each sex (Bateman slopes). The sex with the steeper increase (usually males) is under more intense sexual selection and is expected to compete for access to the sex under less intense sexual selection (usually females). Under Bateman and modern refinements of his ideas, differences in parental investment are key to defining Bateman slopes and thus sex roles. Other theories predict sex differences in mating investment, or any expenditures that reduce male potential reproductive rate, can also control sex roles. We focus on sexual behaviour in systems where males have low paternal investment but frequently mate only once in their lifetimes, after which they are often killed by the female. Mating effort (=terminal investment) is high for these males, and many forms of investment theory might predict sex role reversal. We find no qualitative evidence for sex role reversal in a sample of spiders that show this extreme male investment pattern. We also present new data for terminally-investing redback spiders (Latrodectus hasselti). Bateman slopes are relatively steep for male redbacks, and, as predicted by Bateman, there is little evidence for role reversal. Instead, males are competitive and show limited choosiness despite wide variation in female reproductive value. This study supports the proposal that high male mating investment coupled with low parental investment may predispose males to choosiness but will not lead to role reversal. We support the utility of using Bateman slopes to predict sex roles, even in systems with extreme male mating investment.

Mating regulates neuromodulator ensembles at nerve termini innervating the Drosophila reproductive tract.

PubMed

Heifetz, Yael; Lindner, Moshe; Garini, Yuval; Wolfner, Mariana F

2014-03-31

Upon mating, regions of the female reproductive tract mature and alter their function [1-3], for example to facilitate storage of sperm or control the release of eggs [4-6]. The female's nervous system and neuromodulators play important roles in her responses to mating [7-13]. However, it is difficult to reconcile the reproductive tract's many changing but coordinated events with the small set of neuromodulators present [14-18]. We hypothesized that each part of the reproductive tract contains a characteristic combination of neuromodulators that confer unique identities on each region and that postmating changes in these combinations coordinate subsequent actions. We examined the presence, locations, and levels of neuromodulators and related molecules ("signaling molecules") in the reproductive tract of Drosophila melanogaster females before and after mating: the biogenic amine octopamine, which regulates ovulation rate in Drosophila and locusts [7, 14-20]; serotonin, which regulates muscle contraction in locust oviducts [21]; and the FMRF amide dromyosuppressin, which regulates contraction of Drosophila heart muscle [22] and may regulate muscle contractions in the reproductive tract, if it is expressed there. We find that separate aspects of mating (sperm, seminal proteins, and physical effects) independently modulate the release of signaling molecules. Each reproductive tract subregion displays a characteristic combination of signaling molecule release, resulting in a unique functional identity. These patterns, and thus functions, change reproducibly after mating. Thus, one event (mating) promotes new combinations of signaling molecules that endow different parts of the reproductive tract with unique temporal and spatial identities that facilitate many aspects of fertilization. Copyright © 2014 Elsevier Ltd. All rights reserved.

The impact of plant and flower age on mating patterns

PubMed Central

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

Genetic structure and breeding system in a social wasp and its social parasite

PubMed Central

2008-01-01

Background Social insects dominate ecological communities because of their sophisticated group behaviors. However, the intricate behaviors of social insects may be exploited by social parasites, which manipulate insect societies for their own benefit. Interactions between social parasites and their hosts lead to unusual coevolutionary dynamics that ultimately affect the breeding systems and population structures of both species. This study represents one of the first attempts to understand the population and colony genetic structure of a parasite and its host in a social wasp system. Results We used DNA microsatellite markers to investigate gene flow, genetic variation, and mating behavior of the facultative social parasite Vespula squamosa and its primary host, V. maculifrons. Our analyses of genetic variability uncovered that both species possessed similar amounts of genetic variation and failed to show genetic structure over the sampling area. Our analysis of mating system of V. maculifrons and V. squamosa revealed high levels of polyandry and no evidence for inbreeding in the two species. Moreover, we found no significant differences between estimates of worker relatedness in this study and a previous investigation conducted over two decades ago, suggesting that the selective pressures operating on queen mate number have remained constant. Finally, the distribution of queen mate number in both species deviated from simple expectations suggesting that mate number may be under stabilizing selection. Conclusion The general biology of V. squamosa has not changed substantially from that of a typical, nonparasitic Vespula wasp. For example, population sizes of the host and its parasite appear to be similar, in contrast to other social parasites, which often display lower population sizes than their hosts. In addition, parasitism has not caused the mating behavior of V. squamosa queens to deviate from the high levels of multiple mating that typify Vespula wasps. This stands in contrast to some socially parasitic ants, which revert to mating with few males. Overall, the general similarity of the genetic structure of V. maculifrons and V. squamosa presumably reflects the fact that V. squamosa is still capable of independent colony founding and thus reflects an intermediate stage in the evolution of social parasitism. PMID:18715511

A contact anti-aphrodisiac pheromone supplied by the spermatophore in the rove beetle Aleochara curtula: mode of transfer and evolutionary significance

NASA Astrophysics Data System (ADS)

Schlechter-Helas, Jerry; Schmitt, Thomas; Peschke, Klaus

2011-10-01

By reducing the attractiveness of their mating partner via an anti-aphrodisiac pheromone, males can prevent a remating of the female and thus reduce the risk of sperm competition. For females, the main benefit from allowing the chemical manipulation of their attractiveness is probably the avoidance of sexual harassments from rival males. While mating plugs generally constitute a physical barrier which hinders male mating attempts, chemical manipulations must trustfully inform the responding male of the female's reluctance to mate; otherwise, it would be beneficial to ignore the repellent information. In our experiments, males of the polyandrous rove beetle Aleochara curtula chemically manipulated the attractiveness of their mating partner. Coincident with the deposition of a spermatophore into the female genital chamber, an anti-aphrodisiac pheromone was transferred and readily spread onto the female surface, where it was subsequently perceived by rival males via parameres, the claspers of the male genitalia. Males aborted contact with the mated female to avoid further time- and energy-consuming elements of the mating sequence. The chemical mode of action was demonstrated inter alia by spicing virgin females with spermatophore extracts. The action of the anti-aphrodisiac correlated with the persistence of the spermatophore in the female genital chamber and corresponded to the length of stay of the mated female at a carcass, where the density of rival males is highest. The ensuing benefits for all three parties involved in this communication system, which render this post-copulatory mate guarding strategy evolutionary stable, are discussed.

The impact of sex-role reversal on the diversity of the major histocompatibility complex: Insights from the seahorse (Hippocampus abdominalis)

PubMed Central

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

Interracial and Intraracial Patterns of Mate Selection among America's Diverse Black Populations

ERIC Educational Resources Information Center

Batson, Christie D.; Qian, Zhenchao; Lichter, Daniel T.

2006-01-01

Despite recent immigration from Africa and the Caribbean, Blacks in America are still viewed as a monolith in many previous studies. In this paper, we use newly released 2000 census data to estimate log-linear models that highlight patterns of interracial and intraracial marriage and cohabitation among African Americans, West Indians, Africans,…

Testing for Non-Random Mating: Evidence for Ancestry-Related Assortative Mating in the Framingham Heart Study

PubMed Central

Sebro, Ronnie; Hoffman, Thomas J.; Lange, Christoph; Rogus, John J.; Risch, Neil J.

2013-01-01

Population stratification leads to a predictable phenomenon—a reduction in the number of heterozygotes compared to that calculated assuming Hardy-Weinberg Equilibrium (HWE). We show that population stratification results in another phenomenon—an excess in the proportion of spouse-pairs with the same genotypes at all ancestrally informative markers, resulting in ancestrally related positive assortative mating. We use principal components analysis to show that there is evidence of population stratification within the Framingham Heart Study, and show that the first principal component correlates with a North-South European cline. We then show that the first principal component is highly correlated between spouses (r=0.58, p=0.0013), demonstrating that there is ancestrally related positive assortative mating among the Framingham Caucasian population. We also show that the single nucleotide polymorphisms loading most heavily on the first principal component show an excess of homozygotes within the spouses, consistent with similar ancestry-related assortative mating in the previous generation. This nonrandom mating likely affects genetic structure seen more generally in the North American population of European descent today, and decreases the rate of decay of linkage disequilibrium for ancestrally informative markers. PMID:20842694

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.

Assessing implicit mate preferences among Chinese and Japanese women by providing love, sex, or money cues.

PubMed

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.

HOW MATE AVAILABILITY INFLUENCES FILIAL CANNIBALISM.

PubMed

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.

Female guppies agree to differ: phenotypic and genetic variation in mate-choice behavior and the consequences for sexual selection.

PubMed

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.

Reproductive Biology and Mating System Estimates of Two Andean Melocacti, Melocactus schatzlii and M. andinus (Cactaceae)

PubMed Central

Nassar, Jafet M.; Ramírez, Nelson; Lampo, Margarita; González, José Antonio; Casado, Roberto; Nava, Francisco

2007-01-01

Background and Aims The genus Melocactus comprises 36 species of globose cacti with the most derived traits in the Cereeae tribe. It is the proper study system to examine what are the most derived reproductive strategies within that tribe. This study aims to characterize the reproductive biology and to estimate the mating system parameters of two Andean melocacti, Melocactus schatzlii and M. andinus. Methods The reproductive attributes of the two species were described, including floral morphology, anthesis patterns, floral rewards, floral visitors and visitation patterns. Levels of self-compatibility and autonomous self-pollination were estimated by hand-pollination experiments. Mating system estimates were obtained by conducting progeny array analyses using isozymes. Key Results The flowers of the two species present the typical hummingbird-pollination syndrome. Despite their morphological resemblance, the two species differ in flower size, pollen and ovule production and anthesis pattern. Their main pollinator agents are hummingbirds, four species in M. schatzlii and one species in M. andinus. Both cacti are self-compatible and capable of self-pollination without the aid of pollen vectors. Population-level outcrossing rate was higher for M. schatzlii (tm=0·9) than for M. andinus (tm=0·4). At the family level, outcrossing rates for most mothers of M. schatzlii were higher (tm>0·8) than for M. andinus (tm<0·5). Conclusions Although the two cacti are capable of selfing, M. schatzlii is a predominantly outcrossing species, while M. andinus behaves as a mixed-mating cactus. Hummingbirds are the only pollinators responsible for outcrossing and gene flow events in these species. In their absence, both melocacti set seeds by selfing. Based on its low population size, restricted distribution in Venezuela, low rates of floral visits, and high levels of inbreeding, M. andinus is considered to be an endangered species deserving further study to define its conservation status. PMID:17085474

Reproductive biology and mating system estimates of two Andean melocacti, Melocactus schatzlii and M. andinus (Cactaceae).

PubMed

Nassar, Jafet M; Ramírez, Nelson; Lampo, Margarita; González, José Antonio; Casado, Roberto; Nava, Francisco

2007-01-01

The genus Melocactus comprises 36 species of globose cacti with the most derived traits in the Cereeae tribe. It is the proper study system to examine what are the most derived reproductive strategies within that tribe. This study aims to characterize the reproductive biology and to estimate the mating system parameters of two Andean melocacti, Melocactus schatzlii and M. andinus. The reproductive attributes of the two species were described, including floral morphology, anthesis patterns, floral rewards, floral visitors and visitation patterns. Levels of self-compatibility and autonomous self-pollination were estimated by hand-pollination experiments. Mating system estimates were obtained by conducting progeny array analyses using isozymes. The flowers of the two species present the typical hummingbird-pollination syndrome. Despite their morphological resemblance, the two species differ in flower size, pollen and ovule production and anthesis pattern. Their main pollinator agents are hummingbirds, four species in M. schatzlii and one species in M. andinus. Both cacti are self-compatible and capable of self-pollination without the aid of pollen vectors. Population-level outcrossing rate was higher for M. schatzlii (t(m)=0.9) than for M. andinus (t(m)=0.4). At the family level, outcrossing rates for most mothers of M. schatzlii were higher (t(m)>0.8) than for M. andinus (t(m)<0.5). Although the two cacti are capable of selfing, M. schatzlii is a predominantly outcrossing species, while M. andinus behaves as a mixed-mating cactus. Hummingbirds are the only pollinators responsible for outcrossing and gene flow events in these species. In their absence, both melocacti set seeds by selfing. Based on its low population size, restricted distribution in Venezuela, low rates of floral visits, and high levels of inbreeding, M. andinus is considered to be an endangered species deserving further study to define its conservation status.

Sources of variation in plasma corticosterone and dehydroepiandrosterone in the male northern cardinal (Cardinalis cardinalis): II. Effects of urbanization, food supplementation and social stress.

PubMed

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.

The orbiter mate/demate device

NASA Technical Reports Server (NTRS)

Miller, A. J.; Binkley, W. H.

1985-01-01

The numerous components and systems of the space shuttle orbiter mate/demate device (MDD) are discussed. Special emphasis is given, mechanisms and mechanical systems to discuss in general their requirements, functions, and design; and, where applicable, to relate any unusual problems encountered during the initial concept studies, final design, and construction are discussed. The MDD and its electrical, machinery, and mechanical systems, including the main hoisting system, power operated access service platform, wind restrain and adjustment mechanism, etc., were successfully designed and constructed. The MDD was used routinely during the initial orbiter-747 approach and landing test and the more recent orbiter flight tests recovery and mate operations.

Endocrinology of human female sexuality, mating, and reproductive behavior.

PubMed

Motta-Mena, Natalie V; Puts, David A

2017-05-01

Hormones orchestrate and coordinate human female sexual development, sexuality, and reproduction in relation to three types of phenotypic changes: life history transitions such as puberty and childbirth, responses to contextual factors such as caloric intake and stress, and cyclical patterns such as the ovulatory cycle. Here, we review the endocrinology underlying women's reproductive phenotypes, including sexual orientation and gender identity, mate preferences, competition for mates, sex drive, and maternal behavior. We highlight distinctive aspects of women's sexuality such as the possession of sexual ornaments, relatively cryptic fertile windows, extended sexual behavior across the ovulatory cycle, and a period of midlife reproductive senescence-and we focus on how hormonal mechanisms were shaped by selection to produce adaptive outcomes. We conclude with suggestions for future research to elucidate how hormonal mechanisms subserve women's reproductive phenotypes. Copyright © 2016 Elsevier Inc. All rights reserved.

Neural bases of human mate choice: multiple value dimensions, sex difference, and self-assessment system.

PubMed

Funayama, Risa; Sugiura, Motoaki; Sassa, Yuko; Jeong, Hyeonjeong; Wakusawa, Keisuke; Horie, Kaoru; Sato, Shigeru; Kawashima, Ryuta

2012-01-01

Mate choice is an example of sophisticated daily decision making supported by multiple componential processes. In mate-choice literature, different characteristics of the value dimensions, including the sex difference in the value dimensions, and the involvement of self-assessment due to the mutual nature of the choice, have been suggested. We examined whether the brain-activation pattern during virtual mate choice would be congruent with these characteristics in terms of stimulus selectivity and activated brain regions. In measuring brain activity, young men and women were shown two pictures of either faces or behaviors, and they indicated which person they would choose either as a spouse or as a friend. Activation selective to spouse choice was observed face-selectively in men's amygdala and behavior-selectively in women's motor system. During both partner-choice conditions, behavior-selective activation was observed in the temporoparietal regions. Taking the available knowledge of these regions into account, these results are congruent with the suggested characteristics of value dimensions for physical attractiveness, parenting resources, and beneficial personality traits for a long-lasting relationship, respectively. The medial prefrontal and posterior cingulate cortices were nonselectively activated during the partner choices, suggesting the involvement of a self-assessment process. The results thus provide neuroscientific support for the multi-component mate-choice mechanism.

Selection on an antagonistic behavioral trait can drive rapid genital coevolution in the burying beetle, Nicrophorus vespilloides.

PubMed

Hopwood, Paul E; Head, Megan L; Jordan, Eleanor J; Carter, Mauricio J; Davey, Emma; Moore, Allen J; Royle, Nick J

2016-06-01

Male and female genital morphology varies widely across many taxa, and even among populations. Disentangling potential sources of selection on genital morphology is problematic because each sex is predicted to respond to adaptations in the other due to reproductive conflicts of interest. To test how variation in this sexual conflict trait relates to variation in genital morphology we used our previously developed artificial selection lines for high and low repeated mating rates. We selected for high and low repeated mating rates using monogamous pairings to eliminate contemporaneous female choice and male-male competition. Male and female genital shape responded rapidly to selection on repeated mating rate. High and low mating rate lines diverged from control lines after only 10 generations of selection. We also detected significant patterns of male and female genital shape coevolution among selection regimes. We argue that because our selection lines differ in sexual conflict, these results support the hypothesis that sexually antagonistic coevolution can drive the rapid divergence of genital morphology. The greatest divergence in morphology corresponded with lines in which the resolution of sexual conflict over mating rate was biased in favor of male interests. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

The Role of Bioacoustic Signals in Koala Sexual Selection: Insights from Seasonal Patterns of Associations Revealed with GPS-Proximity Units.

PubMed

Ellis, William; FitzGibbon, Sean; Pye, Geoff; Whipple, Bill; Barth, Ben; Johnston, Stephen; Seddon, Jenny; Melzer, Alistair; Higgins, Damien; Bercovitch, Fred

2015-01-01

Despite being a charismatic and well-known species, the social system of the koala (Phascolarctos cinereus--the only extant member of the family Phascolarctidae) is poorly known and much of the koala's sociality and mating behaviors remain un-quantified. We evaluated these using proximity logging-GPS enabled tracking collars on wild koalas and discuss their implications for the mating system of this species. The frequency and duration of male-female encounters increased during the breeding season, with male-male encounters quite uncommon, suggesting little direct mating competition. By comparison, female-female interactions were very common across both seasons. Body mass of males was not correlated with their interactions with females during the breeding season, although male size is associated with a variety of acoustic parameters indicating individuality. We hypothesise that vocal advertising reduces the likelihood of male-male encounters in the breeding season while increasing the rate of male-female encounters. We suggest that male mating-season bellows function to reduce physical confrontations with other males allowing them to space themselves apart, while, at the same time, attracting females. We conclude that indirect male-male competition, female mate choice, and possibly female competition, mediate sexual selection in koalas.

Interspecific aggression, not interspecific mating, drives character displacement in the wing coloration of male rubyspot damselflies (Hetaerina)

PubMed Central

Drury, J. P.; Grether, G. F.

2014-01-01

Traits that mediate intraspecific social interactions may overlap in closely related sympatric species, resulting in costly between-species interactions. Such interactions have principally interested investigators studying the evolution of reproductive isolation via reproductive character displacement (RCD) or reinforcement, yet in addition to reproductive interference, interspecific trait overlap can lead to costly between-species aggression. Previous research on rubyspot damselflies (Hetaerina spp.) demonstrated that sympatric shifts in male wing colour patterns and competitor recognition reduce interspecific aggression, supporting the hypothesis that agonistic character displacement (ACD) drove trait shifts. However, a recent theoretical model shows that RCD overshadows ACD if the same male trait is used for both female mate recognition and male competitor recognition. To determine whether female mate recognition is based on male wing coloration in Hetaerina, we conducted a phenotype manipulation experiment. Compared to control males, male H. americana with wings manipulated to resemble a sympatric congener (H. titia) suffered no reduction in mating success. Thus, female mate recognition is not based on species differences in male wing coloration. Experimental males did, however, experience higher interspecific fighting rates and reduced survival compared to controls. These results greatly strengthen the case for ACD and highlight the mechanistic distinction between ACD and RCD. PMID:25339724

Effects of male fecundity, interindividual distance and anisotropic pollen dispersal on mating success in a Scots pine (Pinus sylvestris) seed orchard

PubMed Central

Torimaru, T; Wennström, U; Lindgren, D; Wang, X-R

2012-01-01

Quantifying the effect of pollen dispersal and flowering traits on mating success is essential for understanding evolutionary responses to changing environments and establishing strategies for forest tree breeding. This study examined, quantitatively, the effects of male fecundity, interindividual distance and anisotropic pollen dispersal on the mating success of Scots pine (Pinus sylvestris), utilizing a well-mapped Scots pine seed orchard. Paternity analysis of 1021 seeds sampled from 87 trees representing 28 clones showed that 53% of the seeds had at least one potential pollen parent within the orchard. Pronounced variation in paternal contribution was observed among clones. Variations in pollen production explained up to 78% of the variation in mating success, which was 11.2 times greater for clones producing the largest amount of pollen than for clones producing the least pollen. Mating success also varied with intertree distance and direction, which explained up to 28% of the variance. Fertilization between neighboring trees 2.3 m apart was 2.4 times more frequent than between trees 4.6 m apart, and up to 12.4 times higher for trees downwind of the presumed prevailing wind direction than for upwind trees. The effective number of pollen donors recorded in the seed orchard (12.2) was smaller than the theoretical expectation (19.7). Based on the empirical observations, a mating model that best describes the gene dispersal pattern in clonal seed orchards was constructed. PMID:21897440

Convergent evolution of a fused sexual cycle promotes the haploid lifestyle

NASA Astrophysics Data System (ADS)

Sherwood, Racquel Kim; Scaduto, Christine M.; Torres, Sandra E.; Bennett, Richard J.

2014-02-01

Sexual reproduction is restricted to eukaryotic species and involves the fusion of haploid gametes to form a diploid cell that subsequently undergoes meiosis to generate recombinant haploid forms. This process has been extensively studied in the unicellular yeast Saccharomyces cerevisiae, which exhibits separate regulatory control over mating and meiosis. Here we address the mechanism of sexual reproduction in the related hemiascomycete species Candida lusitaniae. We demonstrate that, in contrast to S. cerevisiae, C. lusitaniae exhibits a highly integrated sexual program in which the programs regulating mating and meiosis have fused. Profiling of the C. lusitaniae sexual cycle revealed that gene expression patterns during mating and meiosis were overlapping, indicative of co-regulation. This was particularly evident for genes involved in pheromone MAPK signalling, which were highly induced throughout the sexual cycle of C. lusitaniae. Furthermore, genetic analysis showed that the orthologue of IME2, a `diploid-specific' factor in S. cerevisiae, and STE12, the master regulator of S. cerevisiae mating, were each required for progression through both mating and meiosis in C. lusitaniae. Together, our results establish that sexual reproduction has undergone significant rewiring between S. cerevisiae and C. lusitaniae, and that a concerted sexual cycle operates in C. lusitaniae that is more reminiscent of the distantly related ascomycete, Schizosaccharomyces pombe. We discuss these results in light of the evolution of sexual reproduction in yeast, and propose that regulatory coupling of mating and meiosis has evolved multiple times as an adaptation to promote the haploid lifestyle.

Judging a man by the width of his face: the role of facial ratios and dominance in mate choice at speed-dating events.

PubMed

Valentine, Katherine A; Li, Norman P; Penke, Lars; Perrett, David I

2014-03-01

Previous research has shown that men with higher facial width-to-height ratios (fWHRs) have higher testosterone and are more aggressive, more powerful, and more financially successful. We tested whether they are also more attractive to women in the ecologically valid mating context of speed dating. Men's fWHR was positively associated with their perceived dominance, likelihood of being chosen for a second date, and attractiveness to women for short-term, but not long-term, relationships. Perceived dominance (by itself and through physical attractiveness) mediated the relationship between fWHR and attractiveness to women for short-term relationships. Furthermore, men's perceptions of their own dominance showed patterns of association with mating desirability similar to those of fWHR. These results support the idea that fWHR is a physical marker of dominance. This is the first study to show that male dominance and higher fWHRs are attractive to women for short-term relationships in a controlled and interactive situation that could actually lead to mating and dating.

Identification and molecular characterization of a novel circular single-stranded DNA virus associated with yerba mate in Argentina.

PubMed

Bejerman, Nicolás; de Breuil, Soledad; Nome, Claudia

2018-06-06

A single-stranded DNA (ssDNA) virus was detected in Yerba mate samples showing chlorotic linear patterns, chlorotic rings and vein yellowing. The full-genome sequences of six different isolates of this ssDNA circular virus were obtained, which share > 99% sequence identity with each other. The newly identified virus has been tentatively named as yerba mate-associated circular DNA virus (YMaCV). The 2707 nt-long viral genome has two and three open reading frame on its complementary and virion-sense strands, respectively. The coat protein is more similar to that of mastreviruses (44% identity), whereas the replication-associated protein of YMaCV is more similar (49% identity) to that encoded by a recently described, unclassified ssDNA virus isolated on trees in Brazil. This is the first report of a circular DNA virus associated with yerba mate. Its unique genome organization and phylogenetic relationships indicates that YMaCV represents a distinct evolutionary lineage within the ssDNA viruses and therefore this virus should be classified as a member of a new species within an unassigned genus or family.

Genetic variation and population structure of the mixed-mating cactus, Melocactus curvispinus (Cactaceae).

PubMed

Nassar, J M; Hamrick, J L; Fleming, T H

2001-07-01

Genetic diversity was measured in the mixed-mating cactus, Melocactus curvispinus, in Venezuela. Allozyme diversity was surveyed in 19 putative loci over 18 populations. Compared to other plant taxa, this cactus is rich in polymorphic loci (Ps=89.5%), with high numbers of alleles per polymorphic locus (APs=3.82), but moderate levels of heterozygosity (Hes=0.145). Substantial levels of inbreeding were detected across loci and populations at macrogeographic (FIS=0.348) and regional levels (FIS=0.194-0.402). Moderate levels of genetic differentiation among populations were detected at macrogeographical (FST=0.193) and regional (FST=0.084-0.187) scales, suggesting that gene flow is relatively restricted, but increases within regions without topographic barriers. The population genetic structure observed for this cactus was attributed to, at least, three factors: short-distance pollination and seed dispersal, the mixed-mating condition of the species, and genetic drift. High genetic identities between populations (I=0.942) supported the conspecific nature of all populations surveyed. The levels and patterns of genetic structure observed for M. curvispinus were consistent with its mating system and gene dispersal mechanisms.

Beyond sex allocation: the role of mating systems in sexual selection in parasitoid wasps

PubMed Central

Boulton, Rebecca A; Collins, Laura A; Shuker, David M

2015-01-01

Despite the diverse array of mating systems and life histories which characterise the parasitic Hymenoptera, sexual selection and sexual conflict in this taxon have been somewhat overlooked. For instance, parasitoid mating systems have typically been studied in terms of how mating structure affects sex allocation. In the past decade, however, some studies have sought to address sexual selection in the parasitoid wasps more explicitly and found that, despite the lack of obvious secondary sexual traits, sexual selection has the potential to shape a range of aspects of parasitoid reproductive behaviour and ecology. Moreover, various characteristics fundamental to the parasitoid way of life may provide innovative new ways to investigate different processes of sexual selection. The overall aim of this review therefore is to re-examine parasitoid biology with sexual selection in mind, for both parasitoid biologists and also researchers interested in sexual selection and the evolution of mating systems more generally. We will consider aspects of particular relevance that have already been well studied including local mating structure, sex allocation and sperm depletion. We go on to review what we already know about sexual selection in the parasitoid wasps and highlight areas which may prove fruitful for further investigation. In particular, sperm depletion and the costs of inbreeding under chromosomal sex determination provide novel opportunities for testing the role of direct and indirect benefits for the evolution of mate choice. PMID:24981603

The Putative Son's Attractiveness Alters the Perceived Attractiveness of the Putative Father.

PubMed

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.

The evolution of human reproduction: a primatological perspective.

PubMed

Martin, Robert D

2007-01-01

Successful reconstruction of any aspect of human evolution ideally requires broad-based comparisons with other primates, as recognition of general principles provides a more reliable foundation for inference. Indeed, in many cases it is necessary to conduct comparisons with other placental mammals to test interpretations. This review considers comparative evidence with respect to the following topics relating to human reproduction: (1) size of the testes, sperm, and baculum; (2) ovarian processes and mating cyclicity; (3) placentation and embryonic membranes; (4) gestation period and neonatal condition; (5) brain development in relation to reproduction; and (6) suckling and age at weaning. Relative testis size, the size of the sperm midpiece, and perhaps the absence of a baculum indicate that humans are adapted for a mating system in which sperm competition was not a major factor. Because sizes of mammalian gametes do not increase with body size, they are increasingly dwarfed by the size of the female reproductive tract as body size increases. The implications of this have yet to be explored. Primates have long ovarian cycles and humans show an average pattern. Menstruation is completely lacking in strepsirrhine primates, possibly weakly present in tarsiers and variably expressed in simians. The only other mammals reliably reported to show menstruation are bats. Three hypotheses have been proposed to explain the evolution of menstruation (eliminating sperm-borne pathogens; reducing the metabolic cost of a prepared uterine lining; occurrence as a side-effect of physiological changes), but no consensus has emerged. Copulation at times other than the periovulatory period is not unique to humans, and its occurrence during pregnancy is widespread among mammals. Although the human condition is extreme, extended copulation during the ovarian cycle is the norm among simian primates, in stark contrast to prosimians, in which mating is typically restricted to a few days when the female is in oestrus. The model of regular mid-cycle ovulation in simians is questionable. Gestation periods calculated on that basis show greater variability than in other mammals, and evidence from laboratory breeding colonies indicates that an extended mating period is matched by an extended period in which conception can occur. New evidence indicates that the noninvasive placentation found in strepsirrhine primates is not primitive after all. Furthermore, comparative studies reveal that such noninvasive placentation is not "inefficient". Evolution of highly invasive placentation in haplorhine primates is probably linked instead to immunological factors. Primates have relatively long gestation periods, and humans are average in this respect. However, there is evidence that humans show greater maternal investment during pregnancy in comparison with apes. Although the human neonate matches the typical precocial pattern of primates in most respects, a fetal pattern of brain growth continues for a year after birth, such that the human infant is "secondarily altricial" in terms of its dependence on parental care. Nevertheless, the "natural" lactation period of humans is probably about 3 years, fitting the expectation in comparison to other hominoids. (c) 2007 Wiley-Liss, Inc.

Twelve Transmembrane Helices Form the Functional Core of Mammalian MATE1 (Multidrug and Toxin Extruder 1) Protein*

PubMed Central

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

Effects of sodium puddling on male mating success, courtship and flight in a swallowtail butterfly

PubMed Central

Mitra, Chandreyee; Reynoso, Edgar; Davidowitz, Goggy; Papaj, Daniel

2016-01-01

In many Lepidoptera species usually only males puddle for sodium. Two explanations have been offered for this: (1) neuromuscular activity: males need increased sodium for flight because they are more active flyers than females; and (2) direct benefits: sodium is a type of direct benefit provided by males to females via ejaculate during mating. Surprisingly, there is little direct experimental evidence for either of these. In this study, we examined both explanations using the pipevine swallowtail butterfly, Battus philenor L. If sodium increases neuromuscular activity, males consuming sodium should be better fliers than males without sodium. If males collect sodium for nuptial gifts that benefit their mates, males consuming sodium may have greater mating success than males without sodium. In that case, females then need an honest cue/signal of the quality of male-provided direct benefits that they can assess before mating. If sodium affects male courtship flight by increasing neuromuscular activity, how a male courts could serve as such a premating cue/signal of male benefit quality. Therefore, sodium may benefit males in terms of obtaining mates by increasing their neuromuscular activity. In this study we found that males that consumed sodium courted more vigorously and had greater mating success than males that consumed water. In addition, the courtship displays of males consuming sodium were significantly different from those of males consuming water, providing a possible honest cue/signal of male benefit quality that females can assess. Interestingly, we did not find evidence that sodium consumption affects male flight outside of courtship. That only aspects of male flight related to mating were affected by sodium, while aspects of general flight were not, is consistent with the idea that sodium may benefit males in terms of obtaining mates via effects on neuromuscular activity. PMID:27103748

Spatio-Temporal Dynamics of Field Cricket Calling Behaviour: Implications for Female Mate Search and Mate Choice.

PubMed

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.

Disrupting Mating Behavior of Diaphorina citri (Liviidae).

PubMed

Lujo, S; Hartman, E; Norton, K; Pregmon, E A; Rohde, B B; Mankin, R W

2016-12-01

Severe economic damage from citrus greening disease, caused by 'Candidatus Liberibacter asiaticus' bacteria, has stimulated development of methods to reduce mating and reproduction in populations of its insect vector, Diaphorina citri (Hemiptera: Liviidae). Male D. citri find mating partners by walking on host plants, intermittently producing vibrational calls that stimulate duetting replies by receptive females. The replies provide orientational feedback, assisting the search process. To test a hypothesis that D. citri mating can be disrupted using vibrational signals that compete with and/or mask female replies, courtship bioassays were conducted in citrus trees with or without interference from female reply mimics produced by a vibrating buzzer. Statistically significant reductions occurred in the rates and proportions of mating when the buzzer produced reply mimics within 0.4 s after male courtship calls compared with undisturbed controls. Observations of courtship behaviors in the two bioassays revealed activity patterns that likely contributed to the reductions. In both disruption and control tests, males reciprocated frequently between structural bifurcations and other transition points where signal amplitudes changed. Males in the disruption bioassay had to select among vibrational signals combined from the buzzer and the female at each transition point. They often turned towards the buzzer instead of the female. There was a statistically significant reduction in the proportion of males mating if they contacted the buzzer, possibly due to its higher vibration amplitude and duration in comparison with female replies. Potential applications of D. citri mating disruption technology in citrus groves are discussed. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.

Urinary C-peptide levels in male bonobos (Pan paniscus) are related to party size and rank but not to mate competition.

PubMed

Surbeck, Martin; Deschner, Tobias; Behringer, Verena; Hohmann, Gottfried

2015-05-01

Within- and between-species variation in male mating strategies has been attributed to a multitude of factors including male competitive ability and the distribution of fertile females across space and time. Differences in energy balance across and within males allow for the identification of some of the trade-offs associated with certain social and mating strategies. Bonobos live in groups with a high degree of fission-fusion dynamics, there is co-dominance between the sexes and a linear dominance hierarchy among males. Males compete over access to females, breeding is aseasonal, and females exhibit sexual swellings over extended time periods. In this study we use urinary C-peptide (UCP) levels in male bonobos (Pan paniscus) obtained from 260 urine samples from a wild bonobo community, to quantify male energy balance during mate competition and levels of gregariousness in the species. Although high ranking males are more aggressive, spend more time in proximity to maximally tumescent females, and have higher mating frequencies, we found no indication that mate guarding or mate competition affected male energy balance. Our results showed a positive correlation between monthly mean UCP levels and mean party size. When traveling in large parties, high ranking males had higher UCP levels than those of the low ranking males. These results support the hypothesis that patterns of fission-fusion dynamics in bonobos are either linked to energy availability in the environment or to the energetic costs of foraging. The finding of a rank-bias in UCP levels in larger parties could also reflect an increase in contest competition among males over access to food. Copyright © 2015. Published by Elsevier Inc.

The post-pollination ethylene burst and the continuation of floral advertisement are harbingers of non-random mate selection in Nicotiana attenuata.

PubMed

Bhattacharya, Samik; Baldwin, Ian T

2012-08-01

The self-compatible plant Nicotiana attenuata grows in genetically diverse populations after fires, and produces flowers that remain open for 3 days and are visited by assorted pollinators. To determine whether and when post-pollination non-random mate selection occurs among self and non-self pollen, seed paternity and semi-in vivo pollen tube growth were determined in controlled single/mixed pollinations. Despite all pollen sources being equally proficient in siring seeds in single-genotype pollinations, self pollen was consistently selected in mixed pollinations, irrespective of maternal genotype. However, clear patterns of mate discrimination occurred amongst non-self pollen when mixed pollinations were performed soon after corollas open, including selection against hygromycin B resistance (transformation selectable marker) in wild-type styles and for it in transformed styles. However, mate choice among pollen genotypes was completely shut down in plants transformed to be unable to produce (irACO) or perceive (ETR1) ethylene. The post-pollination ethylene burst, which originates primarily from the stigma and upper style, was strongly correlated with mate selection in single and mixed hand-pollinations using eight pollen donors in two maternal ecotypes. The post-pollination ethylene burst was also negatively correlated with the continuation of emission of benzylacetone, the most abundant pollinator-attracting corolla-derived floral volatile. We conclude that ethylene signaling plays a pivotal role in mate choice, and the post-pollination ethylene burst and the termination of benzylacetone release are accurate predictors, both qualitatively and quantitatively, of pre-zygotic mate selection and seed paternity. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

Female mate choice in convict cichlids is transitive and consistent with a self-referent directional preference

PubMed Central

2013-01-01

Introduction One of the most important decisions that an animal has to make in its life is choosing a mate. Although most studies in sexual selection assume that mate choice is rational, this assumption has not been tested seriously. A crucial component of rationality is that animals exhibit transitive choices: if an individual prefers option A over B, and B over C, then it also prefers A over C. Results We assessed transitivity in mate choice: 40 female convict cichlids had to make a series of binary choices between males of varying size. Ninety percent of females showed transitive choices. The mean preference index was significantly higher when a female chose between their most preferred and least preferred male (male 1 vs. male 3) compared to when they chose between males of adjacent ranks (1 vs. 2 or 2 vs. 3). The results are consistent with a simple underlying preference function leading to transitive choice: females preferred males about one third larger than themselves. This rule of thumb correctly predicted which male was preferred in 67% of the cases and the ordering in binary choices in 78% of cases. Conclusions This study provides the first evidence for strong stochastic transitivity in a context of mate choice. The females exhibited ordinal preferences and the direction and magnitude of these preferences could be predicted from a simple rule. The females do not necessarily compare two males to choose the best; it is sufficient to use a self-referent evaluation. Such a simple decision rule has important implications for the evolution of the mating strategies and it is consistent with patterns of assortative mating repeatedly observed at population level. PMID:24216003

The role of ecology in speciation by sexual selection: a systematic empirical review.

PubMed

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.

Decision making and preferences for acoustic signals in choice situations by female crickets.

PubMed

Gabel, Eileen; Kuntze, Janine; Hennig, R Matthias

2015-08-01

Multiple attributes usually have to be assessed when choosing a mate. Efficient choice of the best mate is complicated if the available cues are not positively correlated, as is often the case during acoustic communication. Because of varying distances of signalers, a female may be confronted with signals of diverse quality at different intensities. Here, we examined how available cues are weighted for a decision by female crickets. Two songs with different temporal patterns and/or sound intensities were presented in a choice paradigm and compared with female responses from a no-choice test. When both patterns were presented at equal intensity, preference functions became wider in choice situations compared with a no-choice paradigm. When the stimuli in two-choice tests were presented at different intensities, this effect was counteracted as preference functions became narrower compared with choice tests using stimuli of equal intensity. The weighting of intensity differences depended on pattern quality and was therefore non-linear. A simple computational model based on pattern and intensity cues reliably predicted female decisions. A comparison of processing schemes suggested that the computations for pattern recognition and directionality are performed in a network with parallel topology. However, the computational flow of information corresponded to serial processing. © 2015. Published by The Company of Biologists Ltd.

What shapes the continuum of reproductive isolation? Lessons from Heliconius butterflies.

PubMed

Mérot, C; Salazar, C; Merrill, R M; Jiggins, C D; Joron, M

2017-06-14

The process by which species evolve can be illuminated by investigating barriers that limit gene flow between taxa. Recent radiations, such as Heliconius butterflies, offer the opportunity to compare isolation between pairs of taxa at different stages of ecological, geographical, and phylogenetic divergence. Here, we report a comparative analysis of existing and novel data in order to quantify the strength and direction of isolating barriers within a well-studied clade of Heliconius Our results highlight that increased divergence is associated with the accumulation of stronger and more numerous barriers to gene flow. Wing pattern is both under natural selection for Müllerian mimicry and involved in mate choice, and therefore underlies several isolating barriers. However, pairs which share a similar wing pattern also display strong reproductive isolation mediated by traits other than wing pattern. This suggests that, while wing pattern is a key factor for early stages of divergence, it may become facultative at later stages of divergence. Additional factors including habitat partitioning, hybrid sterility, and chemically mediated mate choice are associated with complete speciation. Therefore, although most previous work has emphasized the role of wing pattern, our comparative results highlight that speciation is a multi-dimensional process, whose completion is stabilized by many factors. © 2017 The Author(s).

Patterns of testicular activity in captive and wild Canada lynx (Lynx canadensis)

Treesearch

Kerry Fanson; Nadja C. Wielebnowski; Tanya M. Shenk; Walter J. Jakubas; John R. Squires; Jeffrey R. Lucas

2010-01-01

Canada lynx are listed as a threatened species in the contiguous US. Understanding the reproductive characteristics (i.e., mating system, behavior, physiology) of a species is useful for ensuring effective in situ and ex situ management plans. The goal of this study was to describe patterns of androgen expression in both captive and wild male Canada lynx using...

Do extra-group fertilizations increase the potential for sexual selection in male mammals?

PubMed

Isvaran, Kavita; Sankaran, Sumithra

2017-10-01

Fertilizations by males outside the social breeding group (extra-group paternity, EGP) are widespread in birds and mammals. EGP is generally proposed to increase male reproductive skew and thereby increase the potential for sexual selection, but the generality of this relationship is unclear. We extracted data from 27 mammals in seven orders and used phylogenetic comparative methods to investigate the influence of EGP and social mating system on measures of inequality in male fertilization success, which are indices of the potential for sexual selection. We find that EGP and social mating system can predict the potential for sexual selection in mammalian populations, but only when considered jointly and not individually. EGP appears to increase the potential for sexual selection but only when the degree of social polygyny is relatively low. When social polygyny is high, EGP appears to result in a more uniform distribution of reproduction and a decrease in the potential for sexual selection. A possible explanation to be investigated is that the phenotype of extra-group fathers differs systematically across social mating systems. Our findings have implications for the use of EGP and social mating system as indices of sexual selection in comparative analyses of trait evolution under sexual selection. © 2017 The Author(s).

Mate desertion in the snail kite

USGS Publications Warehouse

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.

Male accessory gland substances from Aedes albopictus affect the locomotor activity of Aedes aegypti females

PubMed Central

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

Mate choice for genetic quality when environments vary: suggestions for empirical progress.

PubMed

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?

A general stochastic model for sporophytic self-incompatibility.

PubMed

Billiard, Sylvain; Tran, Viet Chi

2012-01-01

Disentangling the processes leading populations to extinction is a major topic in ecology and conservation biology. The difficulty to find a mate in many species is one of these processes. Here, we investigate the impact of self-incompatibility in flowering plants, where several inter-compatible classes of individuals exist but individuals of the same class cannot mate. We model pollen limitation through different relationships between mate availability and fertilization success. After deriving a general stochastic model, we focus on the simple case of distylous plant species where only two classes of individuals exist. We first study the dynamics of such a species in a large population limit and then, we look for an approximation of the extinction probability in small populations. This leads us to consider inhomogeneous random walks on the positive quadrant. We compare the dynamics of distylous species to self-fertile species with and without inbreeding depression, to obtain the conditions under which self-incompatible species can be less sensitive to extinction while they can suffer more pollen limitation. © Springer-Verlag 2011

Inter-genomic sexual conflict drives antagonistic coevolution in harvester ants

PubMed Central

Herrmann, Michael; Cahan, Sara Helms

2014-01-01

The reproductive interests of males and females are not always aligned, leading to sexual conflict over parental investment, rate of reproduction and mate choice. Traits that increase the genetic interests of one sex often occur at the expense of the other, selecting for counter-adaptations leading to antagonistic coevolution. Reproductive conflict is not limited to intraspecific interactions; interspecific hybridization can produce pronounced sexual conflict between males and females of different species, but it is unclear whether such conflict can drive sexually antagonistic coevolution between reproductively isolated genomes. We tested for hybridization-driven sexually antagonistic adaptations in queens and males of the socially hybridogenetic ‘J’ lineages of Pogonomyrmex harvester ants, whose mating system promotes hybridization in queens but selects against it in males. We conducted no-choice mating assays to compare patterns of mating behaviour and sperm transfer between inter- and intra-lineage pairings. There was no evidence for mate discrimination on the basis of pair type, and the total quantity of sperm transferred did not differ between intra- and inter-lineage pairs; however, further dissection of the sperm transfer process into distinct mechanistic components revealed significant, and opposing, cryptic manipulation of copulatory investment by both sexes. Males of both lineages increased their rate of sperm transfer to high-fitness intra-lineage mates, with a stronger response in the rarer lineage for whom mating mistakes are the most likely. By contrast, the total duration of copulation for intra-lineage mating pairs was significantly shorter than for inter-lineage crosses, suggesting that queens respond to prevent excessive sperm loading by prematurely terminating copulation. These findings demonstrate that sexual conflict can lead to antagonistic coevolution in both intra-genomic and inter-genomic contexts. Indeed, the resolution of sexual conflict may be a key determinant of the long-term evolutionary potential of host-dependent reproductive strategies, counteracting the inherent instabilities arising from such systems. PMID:25355474

Density drives polyandry and relatedness influences paternal success in the Pacific gooseneck barnacle, Pollicipes elegans.

PubMed

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.

Social pairing and female mating fidelity predicted by restriction fragment length polymorphism similarity at the major histocompatibility complex in a songbird.

PubMed

Freeman-Gallant, Corey R; Meguerdichian, Michael; Wheelwright, Nathaniel T; Sollecito, Suzanne V

2003-11-01

Female birds often copulate outside the pair-bond to produce broods of mixed paternity, but despite much recent attention the adaptive significance of this behaviour remains elusive. Although several studies support the idea that extra-pair copulations (EPCs) allow females to obtain 'good genes' for their offspring, many others have found no relationship between female mating fidelity and traits likely to reflect male quality. A corollary to the good genes hypothesis proposes that females do use EPCs to increase the quality of young, but it is the interaction between maternal and paternal genomes - and not male quality per se - that is the target of female choice. We tested this 'genetic compatibility' hypothesis in a free-living population of Savannah sparrows (Passerculus sandwichensis) by determining whether females mated nonrandomly with respect to the major histocompatibility complex (Mhc). During both the 1994 and 1995 breeding seasons, female yearlings (but not older birds) avoided pairing with Mhc-similar males (P < 0.005). The Mhc similarity between mates also predicted the occurrence of extra-pair young in first broods (P < 0.007) and covaried with estimates of genome-wide levels of similarity derived from multilocus DNA fingerprinting profiles (P = 0.007). The overall genetic similarity between adults tended to predict female mating fidelity, but with less precision than their Mhc similarity (P = 0.09). In contrast, females appeared insensitive to the size, weight or age of males, none of which explained variation in female mating fidelity. Taken together, these results are consistent with the hypothesis that females sought complementary genes for their offspring and suggest either that the benefits of heterozygosity (at the Mhc) drive female mating patterns or that the avoidance of inbreeding is an ultimate cause of social and genetic mate choice in Savannah sparrows.

Mating Disruption as a Suppression Tactic in Programs Targeting Regulated Lepidopteran Pests in US.

PubMed

Lance, David R; Leonard, Donna S; Mastro, Victor C; Walters, Michelle L

2016-07-01

Mating disruption, the broadcast application of sex-attractant pheromone to reduce the ability of insects to locate mates, has proven to be an effective method for suppressing populations of numerous moth pests. Since the conception of mating disruption, the species-specificity and low toxicity of pheromone applications has led to their consideration for use in area-wide programs to manage invasive moths. Case histories are presented for four such programs where the tactic was used in the United States: Pectinophora gossypiella (pink bollworm), Lymantria dispar (gypsy moth), Epiphyas postvittana (light brown apple moth), and Lobesia botrana (European grapevine moth). Use of mating disruption against P. gossypiella and L. botrana was restricted primarily to agricultural areas and relied in part (P. gossypiella) or wholly (L. botrana) on hand-applied dispensers. In those programs, mating disruption was integrated with other suppression tactics and considered an important component of overall efforts that are leading toward eradication of the invasive pests from North America. By contrast, L. dispar and E. postvittana are polyphagous pests, where pheromone formulations have been applied aerially as stand-alone treatments across broad areas, including residential neighborhoods. For L. dispar, mating disruption has been a key component in the program to slow the spread of the infestation of this pest, and the applications generally have been well tolerated by the public. For E. postvittana, public outcry halted the use of aerially applied mating disruption after an initial series of treatments, effectively thwarting an attempt to eradicate this pest from California. Reasons for the discrepancies between these two programs are not entirely clear.

Does the Earth's Magnetic Field Serve as a Reference for Alignment of the Honeybee Waggle Dance?

PubMed Central

Lambinet, Veronika; Hayden, Michael E.; Bieri, Marco; Gries, Gerhard

2014-01-01

The honeybee (Apis mellifera) waggle dance, which is performed inside the hive by forager bees, informs hive mates about a potent food source, and recruits them to its location. It consists of a repeated figure-8 pattern: two oppositely directed turns interspersed by a short straight segment, the “waggle run”. The waggle run consists of a single stride emphasized by lateral waggling motions of the abdomen. Directional information pointing to a food source relative to the sun's azimuth is encoded in the angle between the waggle run line and a reference line, which is generally thought to be established by gravity. Yet, there is tantalizing evidence that the local (ambient) geomagnetic field (LGMF) could play a role. We tested the effect of the LGMF on the recruitment success of forager bees by placing observation hives inside large Helmholtz coils, and then either reducing the LGMF to 2% or shifting its apparent declination. Neither of these treatments reduced the number of nest mates that waggle dancing forager bees recruited to a feeding station located 200 m north of the hive. These results indicate that the LGMF does not act as the reference for the alignment of waggle-dancing bees. PMID:25541731

Mechanisms and Evidence of Genital Coevolution: The Roles of Natural Selection, Mate Choice, and Sexual Conflict

PubMed Central

Brennan, Patricia L.R.; Prum, Richard O.

2015-01-01

Genital coevolution between the sexes is expected to be common because of the direct interaction between male and female genitalia during copulation. Here we review the diverse mechanisms of genital coevolution that include natural selection, female mate choice, male–male competition, and how their interactions generate sexual conflict that can lead to sexually antagonistic coevolution. Natural selection on genital morphology will result in size coevolution to allow for copulation to be mechanically possible, even as other features of genitalia may reflect the action of other mechanisms of selection. Genital coevolution is explicitly predicted by at least three mechanisms of genital evolution: lock and key to prevent hybridization, female choice, and sexual conflict. Although some good examples exist in support of each of these mechanisms, more data on quantitative female genital variation and studies of functional morphology during copulation are needed to understand more general patterns. A combination of different approaches is required to continue to advance our understanding of genital coevolution. Knowledge of the ecology and behavior of the studied species combined with functional morphology, quantitative morphological tools, experimental manipulation, and experimental evolution have been provided in the best-studied species, all of which are invertebrates. Therefore, attention to vertebrates in any of these areas is badly needed. PMID:26134314

Coding the Meaning of Sounds: Contextual Modulation of Auditory Responses in the Basolateral Amygdala

PubMed Central

Grimsley, Jasmine M. S.; Hazlett, Emily G.

2013-01-01

Female mice emit a low-frequency harmonic (LFH) call in association with distinct behavioral contexts: mating and physical threat or pain. Here we report the results of acoustic, behavioral, and neurophysiological studies of the contextual analysis of these calls in CBA/CaJ mice. We first show that the acoustical features of the LFH call do not differ between contexts. We then show that male mice avoid the LFH call in the presence of a predator cue (cat fur) but are more attracted to the same exemplar of the call in the presence of a mating cue (female urine). The males thus use nonauditory cues to determine the meaning of the LFH call, but these cues do not generalize to noncommunication sounds, such as noise bursts. We then characterized neural correlates of contextual meaning of the LFH call in responses of basolateral amygdala (BLA) neurons from awake, freely moving mice. There were two major findings. First, BLA neurons typically displayed early excitation to all tested behaviorally aversive stimuli. Second, the nonauditory context modulates the BLA population response to the LFH call but not to the noncommunication sound. These results suggest that the meaning of communication calls is reflected in the spike discharge patterns of BLA neurons. PMID:24174686

The evolution of males: support for predictions from sex allocation theory using mating arrays of sagittaria latifolia (alismataceae).

PubMed

Perry, Laura E; Dorken, Marcel E

2011-10-01

Investment in male function should often yield diminishing fitness returns, subjecting the evolution of male phenotypes to substantial constraints. In plants, the subdivision of male function via the gradual presentation of pollen might minimize these constraints by preventing the saturation of receptive stigmas. Here, we report on an investigation of (1) patterns of investment in male function by plants in hermaphroditic (monoecious) and dioecious populations of Sagittaria latifolia, and (2) patterns of siring success by males versus hermaphrodites in experimental mating arrays. We show that in natural populations, males from dioecious populations had greater investment in male function than hermaphrodites in monoecious populations. However, as a proportion of total flower production, males presented substantially fewer flowers at once than hermaphrodites. In comparison with hermaphrodites, therefore, males prolonged the period over which they presented pollen. In mating arrays comprised of females, males, and hermaphrodites, siring success by males increased linearly with flower production. This finding is consistent with the existence of a linear gain curve for male function in S. latifolia and supports the idea that the gradual deployment of male function enables plants to avoid diminishing returns on the investment in male function. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Turtle mating patterns buffer against disruptive effects of climate change

PubMed Central

Wright, Lucy I.; Stokes, Kimberley L.; Fuller, Wayne J.; Godley, Brendan J.; McGowan, Andrew; Snape, Robin; Tregenza, Tom; Broderick, Annette C.

2012-01-01

For organisms with temperature-dependent sex determination (TSD), skewed offspring sex ratios are common. However, climate warming poses the unique threat of producing extreme sex ratio biases that could ultimately lead to population extinctions. In marine turtles, highly female-skewed hatchling sex ratios already occur and predicted increases in global temperatures are expected to exacerbate this trend, unless species can adapt. However, it is not known whether offspring sex ratios persist into adulthood, or whether variation in male mating success intensifies the impact of a shortage of males on effective population size. Here, we use parentage analysis to show that in a rookery of the endangered green turtle (Chelonia mydas), despite an offspring sex ratio of 95 per cent females, there were at least 1.4 reproductive males to every breeding female. Our results suggest that male reproductive intervals may be shorter than the 2–4 years typical for females, and/or that males move between aggregations of receptive females, an inference supported by our satellite tracking, which shows that male turtles may visit multiple rookeries. We suggest that male mating patterns have the potential to buffer the disruptive effects of climate change on marine turtle populations, many of which are already seriously threatened. PMID:22279164

Biogeography predicts macro-evolutionary patterning of gestural display complexity in a passerine family.

PubMed

Miles, Meredith C; Cheng, Samantha; Fuxjager, Matthew J

2017-05-01

Gestural displays are incorporated into the signaling repertoire of numerous animal species. These displays range from complex signals that involve impressive and challenging maneuvers, to simpler displays or no gesture at all. The factors that drive this evolution remain largely unclear, and we therefore investigate this issue in New World blackbirds by testing how factors related to a species' geographical distribution and social mating system predict macro-evolutionary patterns of display elaboration. We report that species inhabiting temperate regions produce more complex displays than species living in tropical regions, and we attribute this to (i) ecological factors that increase the competitiveness of the social environment in temperate regions, and (ii) different evolutionary and geological contexts under which species in temperate and tropical regions evolved. Meanwhile, we find no evidence that social mating system predicts species differences in display complexity, which is consistent with the idea that gestural displays evolve independently of social mating system. Together, these results offer some of the first insight into the role played by geographic factors and evolutionary context in the evolution of the remarkable physical displays of birds and other vertebrates. © 2017 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Family feuds: social competition and sexual conflict in complex societies

PubMed Central

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

Family feuds: social competition and sexual conflict in complex societies.

PubMed

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.

NOAA-L satellite is mated to Apogee Kick Motor at Vandenberg AFB

NASA Technical Reports Server (NTRS)

2000-01-01

Inside the B16-10 spacecraft processing hangar at Vandenberg Air Force Base, Calif., workers oversee the mating of the Apogee Kick Motor (below) to the National Oceanic and Atmospheric Administration (NOAA-L) satellite above. NOAA-L is part of the Polar-Orbiting Operational Environmental Satellite (POES) program that provides atmospheric measurements of temperature, humidity, ozone and cloud images, tracking weather patterns that affect the global weather and climate. The launch of the NOAA-L satellite is scheduled no earlier than Sept. 12 aboard a Lockheed Martin Titan II rocket. Marriage and its transition in Bangladesh.

PubMed

Ahmed, A U

1986-01-01

The author examines developments in marriage patterns in Bangladesh in light of social, cultural, and economic conditions. Previous literature on the subject is used to discuss Muslim marriage, Hindu marriage, child marriage, mate selection and social mobility, and the question of a marriage squeeze. "The analysis presents evidence that the society is experiencing a change in its family formation, mating process and family type. This transition is to some extent towards the characteristics of [the] Western World, but in a poor economy. Part of this transition is due to the effect of modernization and part due to increasing poverty." excerpt

Using the satellite-derived normalized difference vegetation index (NDVI) to explain ranging patterns in a lek-breeding antelope: the importance of scale.

PubMed

Bro-Jørgensen, Jakob; Brown, Molly E; Pettorelli, Nathalie

2008-11-01

Lek-breeding species are characterized by a negative association between territorial resource availability and male mating success; however, the impact of resources on the overall distribution patterns of the two sexes in lek systems is not clear. The normalized difference vegetation index (NDVI) has recently emerged as a powerful proxy measure for primary productivity, allowing the links between the distributions of animals and resources to be explored. Using NDVI at four spatial resolutions, we here investigate how the distribution of the two sexes in a lek-breeding population of topi antelopes relates to resource abundance before and during the rut. We found that in the dry season preceding the rut, topi density correlated positively with NDVI at the large, but not the fine, scale. This suggests that before the rut, when resources were relatively scant, topi preferred pastures where green grass was widely abundant. The pattern was less pronounced in males, suggesting that the need for territorial attendance prevents males from tracking resources as freely as females do. During the rut, which occurs in the wet season, both male and female densities correlated negatively with NDVI at the fine scale. At this time, resources were generally plentiful and the results suggest that, rather than by resource maximization, distribution during the rut was determined by benefits of aggregating on relatively resource-poor leks for mating, and possibly antipredator, purposes. At the large scale, no correlation between density and NDVI was found during the rut in either sex, which can be explained by leks covering areas too small to be reflected at this resolution. The study illustrates that when investigating spatial organization, it is important: (1) to choose the appropriate analytic scale, and (2) to consider behavioural as well as strictly ecological factors.

Personality Trait Similarity Between Spouses in Four Cultures

PubMed Central

Martin, Thomas A.; H⊆ebí ková, Martina; Urbánek, Tomáš; Boomsma, Dorret I.; Willemsen, Gonneke; Costa, Paul T.

2008-01-01

We examined patterns of trait similarity (assortative mating) in married couples in four cultures, using both self-reports and spouse ratings on versions of the Revised NEO Personality Inventory. There was evidence of a subtle but pervasive perceived contrast bias in the spouse rating data. However, there was strong agreement across methods of assessment and moderate agreement across cultures in the pattern of results. Most assortment effects were small, but correlations exceeding .40 were seen for a subset of traits, chiefly from the Openness and Agreeableness domains. Except in Russia, where more positive assortment was seen for younger couples, comparisons of younger and older cohorts showed little systematic difference. This suggested that mate selection, rather than convergence over time, accounted for similarity. Future research on personality similarity in dyads can utilize different designs, but should assess personality at both domain and the facet levels. PMID:18665894

Rapid Range Expansion Is Not Restricted by Inbreeding in a Sexually Cannibalistic Spider

PubMed Central

Zimmer, Stefanie M.; Krehenwinkel, Henrik; Schneider, Jutta M.

2014-01-01

Few studies investigated whether rapid range expansion is associated with an individual's short-term fitness costs due to an increased risk of inbred mating at the front of expansion. In mating systems with low male mating rates both sexes share potential inbreeding costs and general mechanisms to avoid or reduce these costs are expected. The spider Argiope bruennichi expanded its range recently and we asked whether rapid settlement of new sites exposes individuals to a risk of inbreeding. We sampled four geographically separated subpopulations, genotyped individuals, arranged matings and monitored hatching success. Hatching success was lowest in egg-sacs derived from sibling pairs and highest in egg-sacs derived from among-population crosses, while within-population crosses were intermediate. This indicates that inbreeding might affect hatching success in the wild. Unlike expected, differential hatching success of within- and among-population crosses did not correlate with genetic distance of mating pairs. In contrast, we found high genetic diversity based on 16 microsatellite markers and a fragment of the mitochondrial COI gene in all populations. Our results suggest that even a very recent settlement secures the presence of genetically different mating partners. This leads to costs of inbreeding since the population is not inbred. PMID:24759976

Intense Sperm-Mediated Sexual Conflict Promotes Reproductive Isolation in Caenorhabditis Nematodes

PubMed Central

Leung, Gemma; Shin, Na-Ra; Cutter, Asher D.; Haag, Eric S.

2014-01-01

Conflict between the sexes over reproductive interests can drive rapid evolution of reproductive traits and promote speciation. Here we show that inter-species mating between Caenorhabditis nematodes sterilizes maternal individuals. The principal effectors of male-induced harm are sperm cells, which induce sterility and shorten lifespan by displacing conspecific sperm, invading the ovary, and sometimes breaching the gonad to infiltrate other tissues. This sperm-mediated harm is pervasive across species, but idiosyncrasies in its magnitude implicate both independent histories of sexually antagonistic coevolution within species and differences in reproductive mode (self-fertilizing hermaphrodites versus females) in determining its severity. Consistent with this conclusion, in androdioecious species the hermaphrodites are more vulnerable, the males more benign, or both. Patterns of assortative mating and a low incidence of invasive sperm occurring with conspecific mating are indicative of ongoing intra-specific sexual conflict that results in inter-species reproductive incompatibility. PMID:25072732

I'm hot, so i'd say you're not: the influence of objective physical attractiveness on mate selection.

PubMed

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.

Long-term movement patterns of a coral reef predator

NASA Astrophysics Data System (ADS)

Heupel, M. R.; Simpfendorfer, C. A.

2015-06-01

Long-term monitoring is required to fully define periodicity and patterns in animal movement. This is particularly relevant for defining what factors are driving the presence, location, and movements of individuals. The long-term movement and space use patterns of grey reef sharks, Carcharhinus amblyrhynchos, were examined on a whole of reef scale in the southern Great Barrier Reef to define whether movement and activity space varied through time. Twenty-nine C. amblyrhynchos were tracked for over 2 years to define movement patterns. All individuals showed high residency within the study site, but also had high roaming indices. This indicated that individuals remained in the region and used all of the monitored habitat (i.e., the entire reef perimeter). Use of space was consistent through time with high reuse of areas most of the year. Therefore, individuals maintained discrete home ranges, but undertook broader movements around the reef at times. Mature males showed greatest variation in movement with larger activity spaces and movement into new regions during the mating season (August-September). Depth use patterns also differed, suggesting behaviour or resource requirements varied between sexes. Examination of the long-term, reef-scale movements of C. amblyrhynchos has revealed that reproductive activity may play a key role in space use and activity patterns. It was unclear whether mating behaviour or an increased need for food to sustain reproductive activity and development played a greater role in these patterns. Reef shark movement patterns are becoming more clearly defined, but research is still required to fully understand the biological drivers for the observed patterns.

Effects of partner beauty on opposite-sex attractiveness judgments.

PubMed

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.

Temporal Genetic Dynamics of an Experimental, Biparental Field Population of Phytophthora capsici

PubMed Central

Carlson, Maryn O.; Gazave, Elodie; Gore, Michael A.; Smart, Christine D.

2017-01-01

Defining the contributions of dispersal, reproductive mode, and mating system to the population structure of a pathogenic organism is essential to estimating its evolutionary potential. After introduction of the devastating plant pathogen, Phytophthora capsici, into a grower’s field, a lack of aerial spore dispersal restricts migration. Once established, coexistence of both mating types results in formation of overwintering recombinant oospores, engendering persistent pathogen populations. To mimic these conditions, in 2008, we inoculated a field with two P. capsici isolates of opposite mating type. We analyzed pathogenic isolates collected in 2009–2013 from this experimental population, using genome-wide single-nucleotide polymorphism markers. By tracking heterozygosity across years, we show that the population underwent a generational shift; transitioning from exclusively F1 in 2009–2010, to multi-generational in 2011, and ultimately all inbred in 2012–2013. Survival of F1 oospores, characterized by heterozygosity excess, coupled with a low rate of selfing, delayed declines in heterozygosity due to inbreeding and attainment of equilibrium genotypic frequencies. Large allele and haplotype frequency changes in specific genomic regions accompanied the generational shift, representing putative signatures of selection. Finally, we identified an approximately 1.6 Mb region associated with mating type determination, constituting the first detailed genomic analysis of a mating type region (MTR) in Phytophthora. Segregation patterns in the MTR exhibited tropes of sex-linkage, where maintenance of allele frequency differences between isolates of opposite mating type was associated with elevated heterozygosity despite inbreeding. Characterizing the trajectory of this experimental system provides key insights into the processes driving persistent, sexual pathogen populations. PMID:28348576

The messenger matters: Pollinator functional group influences mating system dynamics.

PubMed

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.

Female mating preferences determine system-level evolution in a gene network model.

PubMed

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.

Camouflaging moving objects: crypsis and masquerade.

PubMed

Hall, Joanna R; Baddeley, Roland; Scott-Samuel, Nicholas E; Shohet, Adam J; Cuthill, Innes C

2017-01-01

Motion is generally assumed to "break" camouflage. However, although camouflage cannot conceal a group of moving animals, it may impair a predator's ability to single one out for attack, even if that discrimination is not based on a color difference. Here, we use a computer-based task in which humans had to detect the odd one out among moving objects, with "oddity" based on shape. All objects were either patterned or plain, and either matched the background or not. We show that there are advantages of matching both group-mates and the background. However, when patterned objects are on a plain background (i.e., no background matching), the advantage of being among similarly patterned distractors is only realized when the group size is larger (10 compared to 5). In a second experiment, we present a paradigm for testing how coloration interferes with target-distractor discrimination, based on an adaptive staircase procedure for establishing the threshold. We show that when the predator only has a short time for decision-making, displaying a similar pattern to the distractors and the background affords protection even when the difference in shape between target and distractors is large. We conclude that, even though motion breaks camouflage, being camouflaged could help group-living animals reduce the risk of being singled out for attack by predators.

Camouflaging moving objects: crypsis and masquerade

PubMed Central

Hall, Joanna R; Baddeley, Roland; Scott-Samuel, Nicholas E; Shohet, Adam J; Cuthill, Innes C

2017-01-01

Abstract Motion is generally assumed to “break” camouflage. However, although camouflage cannot conceal a group of moving animals, it may impair a predator’s ability to single one out for attack, even if that discrimination is not based on a color difference. Here, we use a computer-based task in which humans had to detect the odd one out among moving objects, with “oddity” based on shape. All objects were either patterned or plain, and either matched the background or not. We show that there are advantages of matching both group-mates and the background. However, when patterned objects are on a plain background (i.e., no background matching), the advantage of being among similarly patterned distractors is only realized when the group size is larger (10 compared to 5). In a second experiment, we present a paradigm for testing how coloration interferes with target-distractor discrimination, based on an adaptive staircase procedure for establishing the threshold. We show that when the predator only has a short time for decision-making, displaying a similar pattern to the distractors and the background affords protection even when the difference in shape between target and distractors is large. We conclude that, even though motion breaks camouflage, being camouflaged could help group-living animals reduce the risk of being singled out for attack by predators. PMID:29622927

Patterns of reproductive isolation in a haplodiploid - strong post-mating, prezygotic barriers among three forms of a social spider mite.

PubMed

Sato, Yukie; Sakamoto, Hironori; Gotoh, Tetsuo; Saito, Yutaka; Chao, Jung-Tai; Egas, Martijn; Mochizuki, Atsushi

2018-06-01

In speciation research, much attention is paid to the evolution of reproductive barriers, preventing diverging groups from hybridizing back into one gene pool. The prevalent view is that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection and genetic drift in groups that are segregated spatially and/or temporally. Reproductive barriers, however, can also be reinforced by natural selection against maladaptive hybridization. These mutually compatible theories are both empirically supported by studies, analysing relationships between intensity of reproductive isolation and genetic distance in sympatric taxa and allopatric taxa. Here, we present the - to our knowledge - first comparative study in a haplodiploid organism, the social spider mite Stigmaeopsis miscanthi, by measuring premating and post-mating, pre- and post-zygotic components of reproductive isolation, using three recently diverged forms of the mite that partly overlap in home range. We carried out cross-experiments and measured genetic distances (mitochondrial DNA and nuclear DNA) among parapatric and allopatric populations of the three forms. Our results show that the three forms are reproductively isolated, despite the absence of premating barriers, and that the post-mating, prezygotic component contributes most to reproductive isolation. As expected, the strength of post-mating reproductive barriers positively correlated with genetic distance. We did not find a clear pattern of prezygotic barriers evolving faster in parapatry than in allopatry, although one form did show a trend in line with the ecological and behavioural relationships between the forms. Our study advocates the versatility of haplodiploid animals for investigating the evolution of reproductive barriers. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

Behaviour of Arctic charr Salvelinus alpinus during an induced mating season in captivity: how male relative size influences male behavioural investment and female preference over time.

PubMed

Bolgan, M; O'Brien, J; Picciulin, M; Manning, L; Gammell, M

2017-04-01

The behaviour of sexually mature Arctic charr Salvelinus alpinus specimens (fifth farm generation) was observed in captivity for four consecutive days. Only agonistic interactions between males of different size were facilitated on the first 2 days, while both agonistic and courtship interactions were possible from the third day up to the end of the experiment. The reliability of behavioural analysis was assessed in order to reduce the possibility of observer errors within the generated datasets. The behavioural investment of big males, small males and females was analysed using general linear models (two-way repeated measures ANOVAs with time and male size as factors). A peak in the agonistic interactions between males occurred during the first day of interactions, where the agonistic investment of big males was significantly higher than that of small males. This resulted in an increased investment in submissive behaviour by the small males, who consistently performed submissive behaviours from the second day of interactions up to the end of the trial. Big males were found to invest significantly more than small males in courtship behaviours for the duration of the trial. Even though females performed inter-sexual behaviours towards both big and small males for the entire observation period, female interaction rate towards big males was higher than towards small males. This study suggests that both male investment in mating behaviour and female preference might be related to male characteristics such as body length and that S. alpinus behavioural patterns and mate choice cues might be strongly context-related and characterized by high levels of behavioural plasticity (i.e. presence-absence of certain behavioural units or potential reversal of a mate choice cue) within the same species. Finally, in light of this, some conservation measures are discussed. In particular, effective management plans should take into account the high level of behavioural plasticity likely to be occurring in this species. © 2016 The Fisheries Society of the British Isles.

The evolution of resistance to two-toxin pyramid transgenic crops.

PubMed

Ives, Anthony R; Glaum, Paul R; Ziebarth, Nicolas L; Andow, David A

2011-03-01

Pyramid transgenic crops that express two Bacillus thuringiensis (Bt) toxins hold great potential for reducing insect damage and slowing the evolution of resistance to the toxins. Here, we analyzed a suite of models for pyramid Bt crops to illustrate factors that should be considered when implementing the high dose-refuge strategy for resistance management; this strategy involves the high expression of toxins in Bt plants and use of non-Bt plants as refuges. Although resistance evolution to pyramid Bt varieties should in general be slower, resistance to pyramid Bt varieties is nonetheless driven by the same evolutionary processes as single Bt-toxin varieties. The main advantage of pyramid varieties is the low survival of insects heterozygous for resistance alleles. We show that there are two modes of resistance evolution. When populations of purely susceptible insects persist, leading to density dependence, the speed of resistance evolution changes slowly with the proportion of refuges. However, once the proportion of non-Bt plants crosses the threshold below which a susceptible population cannot persist, the speed of resistance evolution increases rapidly. This suggests that adaptive management be used to guarantee persistence of susceptible populations. We compared the use of seed mixtures in which Bt and non-Bt plants are sown in the same fields to the use of spatial refuges. As found for single Bt varieties, seed mixtures can speed resistance evolution if larvae move among plants. Devising optimal management plans for deploying spatial refuges is difficult because they depend on crop rotation patterns, whether males or females have limited dispersal, and other characteristics. Nonetheless, the effects of spatial refuges on resistance evolution can be understood by considering the three mechanisms determining the rate of resistance evolution: the force of selection (the proportion of insects killed by Bt), assortative mating (deviations of the proportion of heterozygotes from Hardy-Weinberg equilibrium at the total population level), and male mating success (when males carrying resistance alleles find fewer mates). Of these three, assortative mating is often the least important, even though this mechanism is the most frequently cited explanation for the efficacy of the high dose-refuge strategy.

Trading up: the fitness consequences of divorce in monogamous birds.

PubMed

Culina, Antica; Radersma, Reinder; Sheldon, Ben C

2015-11-01

Social and genetic mating systems play an important role in natural and sexual selection, as well as in the dynamics of populations. In socially monogamous species different genetic mating patterns appear when individuals mate outside the breeding pair within a breeding season (extra-pair mating) or when they change partners between two breeding seasons (widowing or divorce). Divorce can be defined as having occurred when two previously paired individuals are alive during the next breeding season and at least one of them has re-mated with a new partner. In socially monogamous birds divorce is widespread, but it is not clear whether it is a behavioural adaptation to improve the quality of a mating decision or whether, alternatively, it results as a non-selected consequence of other processes: existing studies suggest a heterogeneous set of results with respect to this central question. This heterogeneity could result from a number of factors, ranging from the methodological approaches used, to population- or species-specific characters. In this review we use phylogenetic meta-analyses to assess the evidence that divorce is adaptive (in terms of breeding success) across 64 species of socially monogamous birds. Second, we explore biological and methodological reasons for the heterogeneity in the results of previous studies. Results of our analyses supported the hypothesis that divorce is, in general, an adaptive behavioural strategy as: (1) divorce is triggered by relatively low breeding success; (2) there is a positive change in breeding success as a result of divorce. More specifically, while controlling for methodological moderators, we show that: (i) earlier stages of breeding are better predictors of divorce than later stages (r = 0.231; 95% CI: 0.061-0.391 for clutch size; similar for laying date); (ii) females benefited from divorce more than males in terms of increasing breeding success between successive breeding attempts, with different stages of the breeding cycle improving at different rates (e.g. r = 0.637; 95% CI: 0.328-0.817 for brood-level measures). We show that the effect size was dependent on the methodological approach used across studies and argue that research on the adaptive nature of divorce should be cautious when designing the study and interpreting the results. Altogether, by providing strong evidence that divorce is an adaptive strategy across monogamous birds, the results of our analysis provide a firm ground for further exploration of external covariates of divorce (e.g. demographic factors) and the mechanisms underlying the differences in the effect sizes of the proximal fitness causes and consequences of divorce. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical Society.

Numerical solution of differential equations by artificial neural networks

NASA Technical Reports Server (NTRS)

Meade, Andrew J., Jr.

1995-01-01

Conventionally programmed digital computers can process numbers with great speed and precision, but do not easily recognize patterns or imprecise or contradictory data. Instead of being programmed in the conventional sense, artificial neural networks (ANN's) are capable of self-learning through exposure to repeated examples. However, the training of an ANN can be a time consuming and unpredictable process. A general method is being developed by the author to mate the adaptability of the ANN with the speed and precision of the digital computer. This method has been successful in building feedforward networks that can approximate functions and their partial derivatives from examples in a single iteration. The general method also allows the formation of feedforward networks that can approximate the solution to nonlinear ordinary and partial differential equations to desired accuracy without the need of examples. It is believed that continued research will produce artificial neural networks that can be used with confidence in practical scientific computing and engineering applications.

Colour assortative pairing in a colour polymorphic lizard is independent of population morph diversity

NASA Astrophysics Data System (ADS)

Pérez i de Lanuza, Guillem; Font, Enrique; Carretero, Miguel Ángel

2016-10-01

Previous work with a colour polymorphic population of Podarcis muralis (Lacertidae) revealed that lizards pair by ventral colour, favouring the same colour (i.e. homomorphic) pairs. Such assortative pairing, which probably results in colour assortative mating, can have consequences for the genetic structure of the population and potentially promote speciation. The population previously studied, located in the Pyrenees, encompasses white, yellow and orange animals, as well as intermediate white-orange and yellow-orange morphs. However, other Pyrenean populations of P. muralis have less ventral colour morphs. Our aim in this study is to test the generality of the assortative colour pairing system, extending our previous analyses to populations with different morph compositions and frequencies. The results show that the assortative pattern of pairing is similar in all the populations analysed and, hence, independent of morph composition and not restricted to pentamorphic populations. This suggests that assortative pairing by colour is a general phenomenon for colour polymorphic populations of P. muralis.

Female homosexual behavior and inter-sexual mate competition in Japanese macaques: possible implications for sexual selection theory.

PubMed

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.

Odour-based discrimination of similarity at the major histocompatibility complex in birds

PubMed Central

Strandh, Maria; Mardon, Jérôme; Westerdahl, Helena; Bonadonna, Francesco

2017-01-01

Many animals are known to preferentially mate with partners that are dissimilar at the major histocompatibility complex (MHC) in order to maximize the antigen binding repertoire (or disease resistance) in their offspring. Although several mammals, fish or lizards use odour cues to assess MHC similarity with potential partners, the ability of birds to assess MHC similarity using olfactory cues has not yet been explored. Here we used a behavioural binary choice test and high-throughput-sequencing of MHC class IIB to determine whether blue petrels can discriminate MHC similarity based on odour cues alone. Blue petrels are seabirds with particularly good sense of smell, they have a reciprocal mate choice and are known to preferentially mate with MHC-dissimilar partners. Incubating males preferentially approached the odour of the more MHC-dissimilar female, whereas incubating females showed opposite preferences. Given their mating pattern, females were, however, expected to show preference for the odour of the more MHC-dissimilar male. Further studies are needed to determine whether, as in women and female mice, the preference varies with the reproductive cycle in blue petrel females. Our results provide the first evidence that birds can use odour cues only to assess MHC dissimilarity. PMID:28077776

Equilibrium population dynamics when mating is by mutual choice based on age.

PubMed

Alpern, Steve; Katrantzi, Ioanna; Ramsey, David

2014-06-01

We consider a steady state model of mutual mate choice in which an individual's mate preferences depend on his/her age, and the preferences are over the ages of prospective mates of the opposite sex. We present a discrete time (and age) model corresponding to successive mating seasons. Males are fertile for m periods (corresponding to 'age' i=1 to m) and females for n≤m periods (they have ages j=1 to n), which is all that distinguishes the sexes. Although we can deal with arbitrary preferences, we concentrate on a simple fertility model where the common utility to a male age i and female age j who mate is the number K=min(m-i+1,n-j+1) of future periods of joint fertility. The incoming sex ratio R of age 1 males to age 1 females is given exogenously. In each period individuals are randomly (non assortatively) matched and form a mated couple by mutual consent; otherwise they go into the next period unmated and older. We derive properties of equilibrium threshold acceptance strategies and establish the existence of time-invariant age distributions. Our methods determine the age distribution of couples at marriage (mating) and the population sex ratio (OSR) at equilibrium. Since this can be determined empirically in a population, our model can be used to rule out most systems of age preferences (those not consistent with the observed distribution). This extends earlier models of mutual choice with one dimensional types of Alpern and Reyniers [1999. Strategic mating with homotypic preferences. J. Theor. Biol. 198, 71-88; 2005. Strategic mating with common preferences. J. Theor. Biol. 237, 337-354] where individuals sought, respectively, individuals with similar or high types, but in those models an individual's type was fixed over time. Under the simple fertility model, at equilibrium the maximum age of an acceptable partner is increasing in the age of the searcher. Our results relate to discussions in the literature regarding optimal parental age differences, age-related mate preferences, and to mate choice in general. We believe our model will be used as a tool in future investigations in these areas. Copyright © 2013 Elsevier Inc. All rights reserved.

Sex in Millipedes: Laboratory Studies on Sexual Selection.

ERIC Educational Resources Information Center

Telford, S. R.; Dangerfield, J. M.

1990-01-01

Activities that consider the courtship behavior and mating patterns of millipedes are presented. The functional significance of a behavior that has evolved through indirect competition between males is discussed. The procedures for seven experiments, results, and interpretations are included. (KR)

Sexual Cannibalism as a Manifestation of Sexual Conflict

PubMed Central

Schneider, Jutta M.

2014-01-01

Sexual cannibalism is a well-known example for sexual conflict and has many facets that determine the costs and benefits for the cannibal and the victim. Here, I focus on species in which sexual cannibalism is a general component of a mating system in which males invest maximally in mating with a single (monogyny) or two (bigyny) females. Sexual cannibalism can be a male strategy to maximize paternity and a female strategy to prevent paternity monopolization by any or a particular male. Considerable variation exists between species (1) in the potential of males to monopolize females, and (2) in the success of females in preventing monopolization by males. This opens up exciting future possibilities to investigate sexually antagonistic coevolution in a largely unstudied mating system. PMID:25213095

Genetic Compatibility Underlies Benefits of Mate Choice in an External Fertilizer.

PubMed

Aguirre, J David; Blows, Mark W; Marshall, Dustin J

2016-05-01

Mate choice is a common feature of sexually reproducing species. In sessile or sedentary external fertilizers, however, direct interactions between reproductive partners are minimal, and instead mate recognition and choice must occur at the level of gametes. It is common for some sperm and egg combinations to have higher fertilization success than others, but it remains unclear whether differences in fertilization reflect gamete-level mate choice (GMC) for paternal quality or parental compatibility. Here, we examine the mechanisms underlying GMC in an externally fertilizing ascidian. A manipulative mate-choice assay confirmed that offspring viability was greater in clutches where we allowed GMC than in clutches where we precluded GMC. A complementary quantitative genetic experiment then revealed that paternal quality effects were generally weaker than parental compatibility effects, particularly for the trait combination underlying the benefits of GMC. Overall, our data suggest that gametes that are more compatible at fertilization produce more viable offspring than gametes that are less compatible at fertilization. Therefore, although the regalia we typically associate with sexual selection are absent in external fertilizers, mechanisms that allow females to bias fertilization in favor of some males over others produce significant fitness benefits in organisms reproducing via the ancestral strategy.

Polyandry: the history of a revolution

PubMed Central

Parker, Geoff A.; Birkhead, Tim R.

2013-01-01

We give a historic overview and critical perspective of polyandry in the context of sexual selection. Early approaches tended to obfuscate the fact that the total matings (copulations) by the two sexes is equal, neglecting female interests and that females often mate with (or receive ejaculates from) more than one male (polyandry). In recent years, we have gained much more insight into adaptive reasons for polyandry, particularly from the female perspective. However, costs and benefits of multiple mating are unlikely to be equal for males and females. These must be assessed for each partner at each potential mating between male i and female j, and will often be highly asymmetric. Interests of i and j may be in conflict, with (typically, ultimately because of primordial sex differences) i benefitting and j losing from mating, although theoretically the reverse can also obtain. Polyandry reduces the sex difference in Bateman gradients, and the probability of sexual conflict over mating by: (i) reducing the potential expected value of each mating to males in inverse proportion to the number of mates per female per clutch, and also often by (ii) increasing ejaculate costs through increased sperm allocation. It can nevertheless create conflict over fertilization and increase conflict over parental investment. The observed mean mating frequency for the population (and hence the degree of polyandry) is likely, at least in part, to reflect a resolution of sexual conflict. Immense diversity exists across and within taxa in the extent of polyandry, and views on its significance have changed radically, as we illustrate using avian polyandry as a case study. Despite recent criticisms, the contribution of the early pioneers of sexual selection, Darwin and Bateman, remains generally valid, and should not, therefore, be negated; as with much in science, pioneering advances are more often amplified and refined, rather than replaced with entirely new paradigms. PMID:23339245

Examining the possible functions of kissing in romantic relationships.

PubMed

Wlodarski, Rafael; Dunbar, Robin I M

2013-11-01

Recent research suggests that romantic kissing may be utilized in human sexual relationships to evaluate aspects of a potential mate's suitability, to mediate feelings of attachment between pair-bonded individuals, or to facilitate arousal and initiate sexual relations. This study explored these potential functions of romantic kissing by examining attitudes towards the importance of kissing in the context of various human mating situations. The study involved an international online questionnaire, which was completed by 308 male and 594 female participants aged 18-63 years. Support was found for the hypothesis that kissing serves a useful mate-assessment function: women, high mate-value participants, and participants high in sociosexual orientation placed greater importance on kissing in romantic relationships and stated that an initial kiss was more likely to affect their attraction to a potential mate than did men, low-mate value participants or low sociosexual orientation participants. Kissing also seemed to be utilized in the mediation of pair-bond attachments: kissing was seen to be more important at established stages of relationships by low sociosexual participants, kissing was generally seen as more important in long-term relationship contexts (but particularly so by women), and kissing frequency was found to be related to relationship satisfaction. The findings of this research showed very little evidence to support the hypothesis that the primary function of kissing is to elevate levels of arousal.

Unexpected Strong Polygyny in the Brown-Throated Three-Toed Sloth

PubMed Central

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

Role of social interactions in dynamic patterns of resource patches and forager aggregation.

PubMed

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.

Isolating Spermathecae and Determining Mating Status of Drosophila suzukii: A Protocol for Tissue Dissection and Its Applications

PubMed Central

Avanesyan, Alina; Jaffe, Benjamin D.; Guédot, Christelle

2017-01-01

The spotted wing drosophila, Drosophila suzukii (Diptera: Drosophilidae), is an emerging invasive pest, which attacks a wide variety of fruits and berries. Although previous studies have focused on different aspects of D. suzukii reproductive biology, there are no protocols available for determining the mating status of D. suzukii females and drosophilids in general. In this study, a step-by-step protocol for tissue dissection, isolating spermathecae, and determining the mating status of females was developed specifically for D. suzukii. This protocol is an effective and relatively quick method for determining female mating status. It has important applications from exploring reproductive output of D. suzukii females to understanding the biology of D. suzukii winter morph, which presumably plays the main role in the overwintering of this invasive species. We demonstrated applicability of this protocol for both field collected flies and flies reared in the lab, including fly specimens stored on a long-term basis. PMID:28287438

Grandmothering life histories and human pair bonding.

PubMed

Coxworth, James E; Kim, Peter S; McQueen, John S; Hawkes, Kristen

2015-09-22

The evolution of distinctively human life history and social organization is generally attributed to paternal provisioning based on pair bonds. Here we develop an alternative argument that connects the evolution of human pair bonds to the male-biased mating sex ratios that accompanied the evolution of human life history. We simulate an agent-based model of the grandmother hypothesis, compare simulated sex ratios to data on great apes and human hunter-gatherers, and note associations between a preponderance of males and mate guarding across taxa. Then we explore a recent model that highlights the importance of mating sex ratios for differences between birds and mammals and conclude that lessons for human evolution cannot ignore mammalian reproductive constraints. In contradiction to our claim that male-biased sex ratios are characteristically human, female-biased ratios are reported in some populations. We consider the likelihood that fertile men are undercounted and conclude that the mate-guarding hypothesis for human pair bonds gains strength from explicit links with our grandmothering life history.

Ovarian fluid allows directional cryptic female choice despite external fertilization

PubMed Central

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

Direct reciprocity stabilizes simultaneous hermaphroditism at high mating rates: A model of sex allocation with egg trading.

PubMed

Henshaw, Jonathan M; Kokko, Hanna; Jennions, Michael D

2015-08-01

Simultaneous hermaphroditism is predicted to be unstable at high mating rates given an associated increase in sperm competition. The existence of reciprocal egg trading, which requires both hermaphroditism and high mating rates to evolve, is consequently hard to explain. We show using mathematical models that the presence of a trading economy creates an additional fitness benefit to egg production, which selects for traders to bias their sex allocation toward the female function. This female-biased sex allocation prevents pure females from invading a trading population, thereby allowing simultaneous hermaphroditism to persist stably at much higher levels of sperm competition than would otherwise be expected. More generally, our model highlights that simultaneous hermaphroditism can persist stably when mating opportunities are abundant, as long as sperm competition remains low. It also predicts that reciprocity will select for heavier investment in the traded resource. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Population cage experiments with a vertebrate: The temporal demography and cytonuclear genetics of hybridization on Gambusia fishes

USGS Publications Warehouse

Scribner, Kim T.; Avise, John C.

1994-01-01

The dynamics of mitochondrial and multilocus nuclear genotypic frequencies were monitored for 2 yr in experimental populations established with equal numbers of two poeciliid fishes (Gambusia affinis and Gambusia holbrooki) that hybridize naturally in the southeastern United States. In replicated "small-pool" populations (experiment I), 1018 sampled individuals at six time periods revealed an initial flush of hybridization, followed by a rapid decline in frequencies of G. affinis nuclear and mitochondrial alleles over 64 wk. Decay of gametic and cytonuclear disequilibria differed from expectations under random mating as well as under a model of assortative mating involving empirically estimated mating propensities. In two replicate "large-pond" populations (experiment II), 841 sampled individuals across four reproductive cohorts revealed lower initial frequencies of F1 hybrids than in experiment I, but again G. holbrooki alleles achieved high frequencies over four generations (72 wk). Thus, evolution within experimental Gambusia hybrid populations can be extremely rapid, resulting in consistent loss of G. affinis nuclear and cytoplasmic alleles. Concordance in results between experiments and across genetic markers suggests strong directional selection favoring G. holbrooki genotypes. Results are interpreted in light of previous reports of genotype-specific differences in life-history traits, reproductive ecology, patterns of recruitment, and size-specific mortality, and in the context of patterns of introgression previously studied indirectly from spatial observations on cytonuclear genotypes in natural Gambusia populations.

Men With a Terminal Illness Relax Their Criteria for Facial Attractiveness

PubMed Central

Danel, Dariusz P.; Siennicka, Agnieszka E.; Fedurek, Pawel; Frackowiak, Tomasz; Sorokowski, Piotr; Jankowska, Ewa A.; Pawlowski, Boguslaw

2017-01-01

According to the life history paradigm, in life-threatening conditions, sexual selection criteria are relaxed in order to increase the probability of a last resort reproduction, ultimately contributing to reproductive success. This should be reflected in loosened mating preferences — a process observed in nonhuman animals. Studies investigating this aspect in humans, however, are scarce. This study explored the aesthetic preferences towards facial and nonfacial stimuli in terminally ill patients with heart failure (HF) and their healthy, same-sex peers. The aim was to examine if these two groups of men demonstrate different patterns of aesthetic judgments. Using a 7-point scale, 65 male patients with HF and 143 healthy men evaluated the perceived attractiveness of 15 photographs (five adult male faces, five adult female faces, and five nonfacial pictures). A mixed-design analysis of variance was run to assess group differences in aesthetic preferences. Compared to healthy controls, stimuli. HF patients rated the pictures using significantly higher scores, but this applied only to male and female, but not nonfacial, stimuli. We propose that lower criteria for facial attractiveness in HF patients are linked to relaxation of mate preferences as a result of a life-threatening conditions, and that this process can be an adaptive mating strategy from an ultimate, evolutionary perspective. However, other mechanisms (e.g., seeking social support) may be also responsible for the observed patterns. PMID:28625113

Men With a Terminal Illness Relax Their Criteria for Facial Attractiveness.

PubMed

Danel, Dariusz P; Siennicka, Agnieszka E; Fedurek, Pawel; Frackowiak, Tomasz; Sorokowski, Piotr; Jankowska, Ewa A; Pawlowski, Boguslaw

2017-07-01

According to the life history paradigm, in life-threatening conditions, sexual selection criteria are relaxed in order to increase the probability of a last resort reproduction, ultimately contributing to reproductive success. This should be reflected in loosened mating preferences - a process observed in nonhuman animals. Studies investigating this aspect in humans, however, are scarce. This study explored the aesthetic preferences towards facial and nonfacial stimuli in terminally ill patients with heart failure (HF) and their healthy, same-sex peers. The aim was to examine if these two groups of men demonstrate different patterns of aesthetic judgments. Using a 7-point scale, 65 male patients with HF and 143 healthy men evaluated the perceived attractiveness of 15 photographs (five adult male faces, five adult female faces, and five nonfacial pictures). A mixed-design analysis of variance was run to assess group differences in aesthetic preferences. Compared to healthy controls, stimuli. HF patients rated the pictures using significantly higher scores, but this applied only to male and female, but not nonfacial, stimuli. We propose that lower criteria for facial attractiveness in HF patients are linked to relaxation of mate preferences as a result of a life-threatening conditions, and that this process can be an adaptive mating strategy from an ultimate, evolutionary perspective. However, other mechanisms (e.g., seeking social support) may be also responsible for the observed patterns.

Does Sex Trade with Violence among Genotypes in Drosophila melanogaster?

PubMed Central

Cabral, Larry G.; Foley, Brad R.; Nuzhdin, Sergey V.

2008-01-01

The evolutionary forces shaping the ability to win competitive interactions, such as aggressive encounters, are still poorly understood. Given a fitness advantage for competitive success, variance in aggressive and sexual display traits should be depleted, but a great deal of variation in these traits is consistently found. While life history tradeoffs have been commonly cited as a mechanism for the maintenance of variation, the variability of competing strategies of conspecifics may mean there is no single optimum strategy. We measured the genetically determined outcomes of aggressive interactions, and the resulting effects on mating success, in a panel of diverse inbred lines representing both natural variation and artificially selected genotypes. Males of one genotype which consistently lost territorial encounters with other genotypes were nonetheless successful against males that were artificially selected for supernormal aggression and dominated all other lines. Intransitive patterns of territorial success could maintain variation in aggressive strategies if there is a preference for territorial males. Territorial success was not always associated with male mating success however and females preferred ‘winners’ among some male genotypes, and ‘losers’ among other male genotypes. This suggests that studying behaviour from the perspective of population means may provide limited evolutionary and genetic insight. Overall patterns of competitive success among males and mating transactions between the sexes are consistent with mechanisms proposed for the maintenance of genetic variation due to nonlinear outcomes of competitive interactions. PMID:18414669

Does sex trade with violence among genotypes in Drosophila melanogaster?

PubMed

Cabral, Larry G; Foley, Brad R; Nuzhdin, Sergey V

2008-04-16

The evolutionary forces shaping the ability to win competitive interactions, such as aggressive encounters, are still poorly understood. Given a fitness advantage for competitive success, variance in aggressive and sexual display traits should be depleted, but a great deal of variation in these traits is consistently found. While life history tradeoffs have been commonly cited as a mechanism for the maintenance of variation, the variability of competing strategies of conspecifics may mean there is no single optimum strategy. We measured the genetically determined outcomes of aggressive interactions, and the resulting effects on mating success, in a panel of diverse inbred lines representing both natural variation and artificially selected genotypes. Males of one genotype which consistently lost territorial encounters with other genotypes were nonetheless successful against males that were artificially selected for supernormal aggression and dominated all other lines. Intransitive patterns of territorial success could maintain variation in aggressive strategies if there is a preference for territorial males. Territorial success was not always associated with male mating success however and females preferred 'winners' among some male genotypes, and 'losers' among other male genotypes. This suggests that studying behaviour from the perspective of population means may provide limited evolutionary and genetic insight. Overall patterns of competitive success among males and mating transactions between the sexes are consistent with mechanisms proposed for the maintenance of genetic variation due to nonlinear outcomes of competitive interactions.

Who's My Daddy? Considerations for the influence of sexual selection on multiple paternity in elasmobranch mating systems.

PubMed

Lyons, Kady; Chabot, Chris L; Mull, Christopher G; Paterson Holder, Corinne N; Lowe, Christopher G

2017-08-01

Polyandry resulting in multiply-sired litters has been documented in the majority of elasmobranch species examined to date. Although commonly observed, reasons for this mating system remain relatively obscure, especially in batoids. The round stingray ( Urobatis halleri ) is an abundant, well-studied elasmobranch distributed throughout the northeastern Pacific that we used to explore hypotheses regarding multiple paternity in elasmobranchs. Twenty mid- to late-term pregnant females were sampled off the coast of southern California and their litters analyzed for the occurrence of multiple paternity using five nuclear microsatellite loci. In addition, embryo sizes and their position within the female reproductive system (i.e., right or left uterus) were recorded and used to make inferences for patterns of ovulation. Multiple paternity was observed in 90% of litters and male reproductive success within litters was relatively even among sires. High variability in testes mass was observed suggesting that sperm competition is high in this species, although male reproductive success per litter appeared to be relatively even. Using embryo size as a proxy for fertilization, females were found to exhibit a variety of ovulation patterns that could function to limit a male's access to eggs and possibly promote high rates of multiple paternity. Our study highlights that elasmobranch mating systems may be more varied and complex than presumed and further investigation is warranted.

Mating asymmetry and the direction of evolution in the Hawaiian cricket genus Laupala.

PubMed

Shaw, K L; Lugo, E

2001-03-01

Based on studies from native Hawaiian Drosophila, a model was proposed to explain sexual isolation and mating asymmetry, from which one could potentially infer the 'direction of evolution'. We examined sexual isolation between allopatric cricket species of the genus Laupala, another endemic Hawaiian insect with an elaborate mating system, to begin to explore the nature of sexual isolation and mating asymmetry in closely related Hawaiian organisms. We studied sexual isolation and mating asymmetry in two contrasts. First, an inter-island comparison, including L. makaio from the older island of Maui and L. paranigra from the younger island of Hawaii, and second, an intra-island (Hawaii) comparison, including L. nigra from the older volcano of Mauna Kea and L. paranigra with a primary distribution on the younger volcanoes of Mauna Loa and Kilauea. We used a 'no-choice' experimental design, pairing individual males and females in homospecific or heterospecific combinations. Several behavioural aspects of courtship (proportion of male singing, latency to male singing, production of spermatophores and courtship initiation speed) were quantified as well as the success or failure of matings. We demonstrate asymmetry in sexual isolation between reciprocal combinations of L. makaio and L. paranigra. This result is examined in light of the differences in courtship behaviour manifest in the experiments with these two species. We did not find evidence of asymmetry in sexual isolation between L. nigra and L. paranigra, although differences in courtship initiation speed were evident between reciprocal combinations of these two species. In addition to the geological argument that species on older islands and older volcanoes give rise to species on younger islands and younger volcanoes, we discuss phylogenetic evidence consistent with these biogeographic hypotheses of relationships among the focal taxa. The patterns of asymmetrical sexual isolation and mating asymmetry are consistent with those found in the native Hawaiian Drosophila.

Moderate Multiple Parentage and Low Genetic Variation Reduces the Potential for Genetic Incompatibility Avoidance Despite High Risk of Inbreeding

PubMed Central

Tuni, Cristina; Goodacre, Sara; Bechsgaard, Jesper; Bilde, Trine

2012-01-01

Background Polyandry is widespread throughout the animal kingdom. In the absence of direct benefits of mating with different males, the underlying basis for polyandry is enigmatic because it can carry considerable costs such as elevated exposure to sexual diseases, physical injury or other direct fitness costs. Such costs may be balanced by indirect genetic benefits to the offspring of polyandrous females. We investigated polyandry and patterns of parentage in the spider Stegodyphus lineatus. This species experiences relatively high levels of inbreeding as a result of its spatial population structure, philopatry and limited male mating dispersal. Polyandry may provide an opportunity for post mating inbreeding avoidance that reduces the risk of genetic incompatibilities arising from incestuous matings. However, multiple mating carries direct fitness costs to females suggesting that genetic benefits must be substantial to counter direct costs. Methodology/Principal Findings Genetic parentage analyses in two populations from Israel and a Greek island, showed mixed-brood parentage in approximately 50% of the broods. The number of fathers ranged from 1–2 indicating low levels of multiple parentage and there was no evidence for paternity bias in mixed-broods from both populations. Microsatellite loci variation suggested limited genetic variation within populations, especially in the Greek island population. Relatedness estimates among females in the maternal generation and potentially interacting individuals were substantial indicating full-sib and half-sib relationships. Conclusions/Significance Three lines of evidence indicate limited potential to obtain substantial genetic benefits in the form of reduced inbreeding. The relatively low frequency of multiple parentage together with low genetic variation among potential mates and the elevated risk of mating among related individuals as corroborated by our genetic data suggest that there are limited actual outbreeding opportunities for polyandrous females. Polyandry in S. lineatus is thus unlikely to be maintained through adaptive female choice. PMID:22235316

Extensive long-distance pollen dispersal and highly outcrossed mating in historically small and disjunct populations of Acacia woodmaniorum (Fabaceae), a rare banded iron formation endemic.

PubMed

Millar, Melissa A; Coates, David J; Byrne, Margaret

2014-10-01

Understanding patterns of pollen dispersal and variation in mating systems provides insights into the evolutionary potential of plant species and how historically rare species with small disjunct populations persist over long time frames. This study aims to quantify the role of pollen dispersal and the mating system in maintaining contemporary levels of connectivity and facilitating persistence of small populations of the historically rare Acacia woodmaniorum. Progeny arrays of A. woodmaniorum were genotyped with nine polymorphic microsatellite markers. A low number of fathers contributed to seed within single pods; therefore, sampling to remove bias of correlated paternity was implemented for further analysis. Pollen immigration and mating system parameters were then assessed in eight populations of varying size and degree of isolation. Pollen immigration into small disjunct populations was extensive (mean minimum estimate 40 % and mean maximum estimate 57 % of progeny) and dispersal occurred over large distances (≤1870m). Pollen immigration resulted in large effective population sizes and was sufficient to ensure adaptive and inbreeding connectivity in small disjunct populations. High outcrossing (mean tm = 0·975) and a lack of apparent inbreeding suggested that a self-incompatibility mechanism is operating. Population parameters, including size and degree of geographic disjunction, were not useful predictors of pollen dispersal or components of the mating system. Extensive long-distance pollen dispersal and a highly outcrossed mating system are likely to play a key role in maintaining genetic diversity and limiting negative genetic effects of inbreeding and drift in small disjunct populations of A. woodmaniorum. It is proposed that maintenance of genetic connectivity through habitat and pollinator conservation will be a key factor in the persistence of this and other historically rare species with similar extensive long-distance pollen dispersal and highly outcrossed mating systems. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company.

Protein modification in the post-mating spermatophore of the signal crayfish Pacifastacus leniusculus: insight into the tyrosine phosphorylation in a non-motile spermatozoon.

PubMed

Niksirat, Hamid; Vancová, Marie; Andersson, Liselotte; James, Peter; Kouba, Antonín; Kozák, Pavel

2016-09-01

After mating, spermatophores of signal crayfish are stored on the body of the female for a period before fertilization. This study compared the post-mating protein profile and pattern of protein tyrosine phosphorylation of the signal crayfish spermatophore to that of the freshly ejaculated spermatophore and found substantial differences. Two major bands of tyrosine-phosphorylated proteins of molecular weights 10 and 50kDa were observed in the freshly ejaculated spermatophore of the signal crayfish. While the tyrosine-phosphorylated protein band with molecular weight 10kDa was formed by protein(s) of similar pH, the band with molecular weight of 50kDa consisted of proteins of varying pH. In the post-mating spermatophore, the band with molecular weight of 50kDa was not detected, and an increase in the level of protein tyrosine phosphorylation was observed in the 10kDa band. The microtubular radial arms of the spermatozoon showed a positive reaction to an anti-tyrosine antibody conjugated with gold particles in both the freshly ejaculated and post-mating spermatophores. In conclusion, the male gamete of the signal crayfish undergoes molecular modification during post-mating storage on the body of the female including changes in the level of protein expression and protein tyrosine phosphorylation. Structural similarity of the radial arms in the crayfish immotile spermatozoon with flagellum, which is the main site of protein tyrosine phosphorylation in the mammalian motile spermatozoa, raises questions regarding evolution and function of such organelles across the animal kingdom that must be addressed in the future studies. Copyright © 2016 Elsevier B.V. All rights reserved.

The genetic basis of traits regulating sperm competition and polyandry: can selection favour the evolution of good- and sexy-sperm?

PubMed

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.

Short amplexus duration in a territorial anuran: a possible adaptation in response to male-male competition.

PubMed

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.

Testosterone positively associated with both male mating effort and paternal behavior in savanna baboons (Papio cynocephalus)

PubMed Central

Onyango, Patrick Ogola; Gesquiere, Laurence R.; Altmann, Jeanne; Alberts, Susan C.

2012-01-01

Testosterone (T) is often positively associated with male sexual behavior and negatively associated with paternal care. These associations have primarily been demonstrated in species where investment in paternal care begins well after mating activity is complete, when offspring are hatched or born. Different patterns may emerge in studies of species where investment in mating and paternal care overlap temporally, for instance in non-seasonal breeders in which males mate with multiple females sequentially and may simultaneously have multiple offspring of different ages. In a 9-year data set on levels of T in male baboons, fecal concentrations of T (fT) were positively associated with both mate guarding (“consortship”) – a measure of current reproductive activity – and with the number of immature offspring a male had in his social group – a measure of past reproductive activity and an indicator of likely paternal behavior. To further examine the relationship between T and potential paternal behavior, we next drew on an intensive 8-month study of male behavior, and found that fathers were more likely to be in close proximity to their offspring than expected by chance. Because male baboons are known to provide paternal care, and because time in proximity to offspring would facilitate such care, this suggests that T concentrations in wild male baboons may be associated with both current reproductive activity and with current paternal behavior. These results are consistent with the predicted positive association between T a mating effort but not nd with a negative association between T a paternal care; in male baboons, high levels of nd T occur in males that are differentially associating with their offspring. PMID:23206991

Effects of tree architecture on pollen dispersal and mating patterns in Abies pinsapo Boiss. (Pinaceae).

PubMed

Sánchez-Robles, Jose M; García-Castaño, Juan L; Balao, Francisco; Terrab, Anass; Navarro-Sampedro, Laura; Tremetsberger, Karin; Talavera, Salvador

2014-12-01

Plant architecture is crucial to pollination and mating in wind-pollinated species. We investigated the effect of crown architecture on pollen dispersal, mating system and offspring quality, combining phenotypic and genotypic analyses in a low-density population of the endangered species Abies pinsapo. A total of 598 embryos from three relative crown height levels (bottom, middle and top) in five mother plants were genotyped using eleven nuclear microsatellite markers (nSSRs). Paternity analysis and mating system models were used to infer mating and pollen dispersal parameters. In addition, seeds were weighed (N = 16 110) and germinated (N = 736), and seedling vigour was measured to assess inbreeding depression. Overall, A. pinsapo shows a fat-tailed dispersal kernel, with an average pollen dispersal distance of 113-227 m, an immigration rate of 0.84-26.92%, and a number of effective pollen donors (Nep ) ranging between 3.5 and 11.9. We found an effect of tree height and relative crown height levels on mating parameters. A higher proportion of seeds with embryo (about 50%) and a higher rate of self-fertilization (about 60%) were found at the bottom level in comparison with the top level. Seed weight and seedling vigour are positively related. Nevertheless, no differences were found in seed weight or in seedling-related variables such as weight and length of aerial and subterranean parts among the different relative crown height levels, suggesting that seeds from the more strongly inbred bottom level are not affected by inbreeding depression. Our results point to vertical isotropy for outcross-pollen and they suggest that self-pollen may ensure fertilization when outcross-pollen is not available in low-density population. © 2014 John Wiley & Sons Ltd.

Temporal variation in the mating structure of Sanday, Orkney Islands.

PubMed

Brennan, E R; Relethford, J H

1983-01-01

Pedigree and vital statistics data from the population of Sanday, Orkney Islands, Scotland, were used to assess temporal changes in population structure. Secular trends in patterns of mate choice were analysed for three separate birth cohorts of spouses: 1855-1884, 1885-1924 and 1925-1964. The degree to which mating was random or assortative with respect to both genealogical and geographic distance was determined by comparing average characteristics of all potential mates of married males with those of actual wives. We integrated this procedure, originally developed by Dyke (1971), into a three-fold investigation of population structure: (1) comparison of random and non-random components of relatedness as measured from pedigree data; (2) an analysis of marital distance distributions for actual and potential mates of married males; and (3) the relationship between genealogical relatedness and geographic distance. As population size decreased from 1881 to the present, total kinship and spatial distances between spouses increased. Whereas the random component of relatedness increased over time, consanguinity avoidance was sufficient to decrease the total coefficient of kinship over time. Part of the increase in consanguinity avoidance was associated with isolate breakdown, as distances between island-born spouses, as well as the total amount of off-island migration, increased from the mid-nineteenth century to the present. Mate choice was influenced by geographic distance for all time periods, although this effect diminished over time. Since decreases in population size, concomitant with increases in consanguinity avoidance and community exogamy, have probably occurred quite frequently in small human populations, as well as in rural Western communities in the past century, observed secular trends illustrate the potential for change in population structure characteristic of isolate breakdown.

Pollen, wind and fire: how to investigate genetic effects of disturbance-induced change in forest trees.

PubMed

Bacles, Cecile F E

2014-01-01

Understanding the consequences of habitat disturbance on mating patterns although pollen and seed dispersal in forest trees has been a long-standing theme of forest and conservation genetics. Forest ecosystems face global environmental pressures from timber exploitation to genetic pollution and climate change, and it is therefore essential to comprehend how disturbances may alter the dispersal of genes and their establishment in tree populations in order to formulate relevant recommendations for sustainable resource management practices and realistic predictions of potential adaptation to climate change by means of range shift or expansion (Kremer et al. 2012). However, obtaining reliable evidence of disturbance-induced effects on gene dispersal processes from empirical evaluation of forest tree populations is difficult. Indeed, tree species share characteristics such as high longevity, long generation time and large reproductive population size, which may impede the experimenter's ability to assess parameters at the spatial and time scales at which any change may occur (Petit and Hampe 2006). It has been suggested that appropriate study designs should encompass comparison of populations before and after disturbance as well as account for demonstrated variation in conspecific density, that is, the spatial distribution of mates, and forest density, including all species and relating to alteration in landscape openness (Bacles & Jump 2011). However, more often than not, empirical studies aiming to assess the consequences of habitat disturbance on genetic processes in tree populations assume rather than quantify a change in tree densities in forests under disturbance and generally fail to account for population history, which may lead to inappropriate interpretation of a causal relationship between population genetic structure and habitat disturbance due to effects of unmonitored confounding variables (Gauzere et al. 2013). In this issue, Shohami and Nathan (2014) take advantage of the distinctive features of the fire-adapted wind-pollinated Aleppo pine Pinus halepensis (Fig. 1) to provide an elegant example of best practice. Thanks to long-term monitoring of the study site, a natural stand in Israel, Shohami and Nathan witnessed the direct impact of habitat disturbance, here taking the shape of fire, on conspecific and forest densities and compared pre- and postdisturbance mating patterns estimated from cones of different ages sampled on the same surviving maternal individuals (Fig. 2). This excellent study design is all the more strong that Shohami and Nathan took further analytical steps to account for confounding variables, such as historical population genetic structure and possible interannual variation in wind conditions, thus giving high credibility to their findings of unequivocal fire-induced alteration of mating patterns in P. halepensis. Most notably, the authors found, at the pollen pool level, a disruption of local genetic structure which, furthermore, they were able to attribute explicitly to enhanced pollen-mediated gene immigration into the low-density fire-disturbed stand. This cleverly designed research provides a model approach to be followed if we are to advance our understanding of disturbance-induced dispersal and genetic change in forest trees. © 2013 John Wiley & Sons Ltd.

Density drives polyandry and relatedness influences paternal success in the Pacific gooseneck barnacle, Pollicipes elegans

PubMed Central

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

Genomics and Transcriptomics Analyses of the Oil-Accumulating Basidiomycete Yeast Trichosporon oleaginosus: Insights into Substrate Utilization and Alternative Evolutionary Trajectories of Fungal Mating Systems

PubMed Central

Bracharz, Felix; Lorenzen, Jan; Kracht, Octavia N.; Chovatia, Mansi; Daum, Chris; Deshpande, Shweta; Lipzen, Anna; Nolan, Matt; Ohm, Robin A.; Grigoriev, Igor V.; Sun, Sheng; Heitman, Joseph

2015-01-01

ABSTRACT Microbial fermentation of agro-industrial waste holds great potential for reducing the environmental impact associated with the production of lipids for industrial purposes from plant biomass. However, the chemical complexity of many residues currently prevents efficient conversion into lipids, creating a high demand for strains with the ability to utilize all energy-rich components of agricultural residues. Here, we present results of genome and transcriptome analyses of Trichosporon oleaginosus. This oil-accumulating yeast is able to grow on a wide variety of substrates, including pentoses and N-acetylglucosamine, making it an interesting candidate for biotechnological applications. Transcriptomics shows specific changes in gene expression patterns under lipid-accumulating conditions. Furthermore, gene content and expression analyses indicate that T. oleaginosus is well-adapted for the utilization of chitin-rich biomass. We also focused on the T. oleaginosus mating type, because this species is a member of the Tremellomycetes, a group that has been intensively analyzed as a model for the evolution of sexual development, the best-studied member being Cryptococcus neoformans. The structure of the T. oleaginosus mating-type regions differs significantly from that of other Tremellomycetes and reveals a new evolutionary trajectory paradigm. Comparative analysis shows that recruitment of developmental genes to the ancestral tetrapolar mating-type loci occurred independently in the Trichosporon and Cryptococcus lineages, supporting the hypothesis of a trend toward larger mating-type regions in fungi. PMID:26199329

The vibrational signals that male fiddler crabs ( Uca lactea) use to attract females into their burrows

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.

Dynamics of sperm transfer in the ant Leptothorax gredleri

NASA Astrophysics Data System (ADS)

Oppelt, Angelika; Heinze, Jürgen

2007-09-01

Mating tactics differ remarkably between and within species of social Hymenoptera (bees, wasps, ants) concerning, e.g., mating frequencies, sperm competition, and the degree of male sperm limitation. Although social Hymenoptera might, therefore, potentially be ideal model systems for testing sexual selection theory, the dynamics of mating and sperm transfer have rarely been studied in species other than social bees, and basic information needed to draw conclusions about possible sperm competition and female choice is lacking. We investigated sperm transfer in the ant Leptothorax gredleri, a species in which female sexuals attract males by “female calling.” The analysis of 38 female sexuals fixed immediately or up to 7 days after copulation with a single male each revealed that the sperm is transferred into the female bursa copulatrix embedded in a gelatinous mass, presumably a spermatophore. Sperm cells rapidly start to migrate from the tip of the spermatophore towards the spermatheca, but transfer is drastically slowed down by an extreme constriction of the spermathecal duct, through which sperm cells have to pass virtually one by one. This results in the spermatheca being filled only between one and several hours after mating. During this time, the posterior part of the spermatophore seals the junction between bursa copulatrix and spermathecal duct and prevents sperm loss. The prolonged duration of sperm transfer might allow female sexuals to chose between ejaculates and explain previously reported patterns of single paternity of the offspring of multiply mated queens.

Using time-dependent models to investigate body condition and growth rate of the giant gartersnake

USGS Publications Warehouse

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.

Experimental evidence for asymmetric mate preference and aggression: behavioral interactions in a woodrat (Neotoma) hybrid zone

PubMed Central

2013-01-01

Background Female mate preferences may be under strong selection in zones of contact between closely related species because of greater variation in available mates and the potential costs of hybridization. We studied female mate preferences experimentally in a zone of secondary contact between Desert and Bryant’s Woodrat (Neotoma lepida and N. bryanti) in the southern foothills of the Sierra Nevada of California. We tested female preference for conspecific versus heterospecific males in paired choice trials in which females could interact freely with males, but males could not interact directly with each other. We compared preferences of females from both allopatric and sympatric sites. Results We did not find evidence of the process of reinforcement as assortative preferences were not stronger in sympatry than in allopatry. Mate preferences, however, were asymmetric, with N. lepida females mating preferentially with conspecifics and N. bryanti females showing no preference by species. Sympatric females were less likely to mate than allopatric females, due in part to an increase in aggressive interactions. However, even in the absence of aggression, courtship led to mating less often in sympatric females, suggesting they were choosier or had lower sexual motivation than allopatric females. Conclusions Patterns of mate choice in this woodrat system appear to be strongly impacted by body size and aggressive behavior. In particular, females of the smaller-bodied species rarely interact with the relatively large heterospecific males. In contrast females of the larger-bodied species accept the relatively small heterospecific males. For sympatric animals, rates of aggression were markedly higher than for allopatric animals and reduced affiliative and reproductive behavior in our trials. Sympatric animals are larger and more aggressive, traits that are likely under strong ecological selection across the sharp resource gradient that characterizes the contact zone. However, our results suggest that these traits that are likely favored in competitive interactions between the species also impact reproductive interactions. Combined with our previous findings of post-zygotic isolation in this system, this study suggests that multiple isolating mechanisms contribute to the rate of genetic exchange between these species when they come into contact, and that these mechanisms are the result of selection on traits that are important in a range of ecological and reproductive interactions. PMID:24093823

Genetic mating systems and reproductive natural histories of fishes: lessons for ecology and evolution.

PubMed

Avise, John C; Jones, Adam G; Walker, DeEtte; DeWoody, J Andrew

2002-01-01

Fish species have diverse breeding behaviors that make them valuable for testing theories on genetic mating systems and reproductive tactics. Here we review genetic appraisals of paternity and maternity in wild fish populations. Behavioral phenomena quantified by genetic markers in various species include patterns of multiple mating by both sexes; frequent cuckoldry by males and rare cuckoldry by females in nest-tending species; additional routes to surrogate parentage via nest piracy and egg-thievery; egg mimicry by nest-tending males; brood parasitism by helper males in cooperative breeders; clutch mixing in oral brooders; kinship in schooling fry of broadcast spawners; sperm storage by dams in female-pregnant species; and sex-role reversal, polyandry, and strong sexual selection on females in some male-pregnant species. Additional phenomena addressed by genetic parentage analyses in fishes include clustered mutations, filial cannibalism, and local population size. All results are discussed in the context of relevant behavioral and evolutionary theory.

Correlated evolution in parental care in females but not males in response to selection on paternity assurance behaviour.

PubMed

Head, Megan L; Hinde, Camilla A; Moore, Allen J; Royle, Nick J

2014-07-01

According to classical parental care theory males are expected to provide less parental care when offspring in a brood are less likely to be their own, but empirical evidence in support of this relationship is equivocal. Recent work predicts that social interactions between the sexes can modify co-evolution between traits involved in mating and parental care as a result of costs associated with these social interactions (i.e. sexual conflict). In burying beetles (Nicrophorus vespilloides), we use artificial selection on a paternity assurance trait, and crosses within and between selection lines, to show that selection acting on females, not males, can drive the co-evolution of paternity assurance traits and parental care. Males do not care more in response to selection on mating rate. Instead, patterns of parental care change as an indirect response to costs of mating for females. © 2014 The Authors. Ecology Letters published by John Wiley & Sons Ltd and CNRS.

Going All In: Unfavorable Sex Ratios Attenuate Choice Diversification.

PubMed

Ackerman, Joshua M; Maner, Jon K; Carpenter, Stephanie M

2016-06-01

When faced with risky decisions, people typically choose to diversify their choices by allocating resources across a variety of options and thus avoid putting "all their eggs in one basket." The current research revealed that this tendency is reversed when people face an important cue to mating-related risk: skew in the operational sex ratio, or the ratio of men to women in the local environment. Counter to the typical strategy of choice diversification, findings from four studies demonstrated that the presence of romantically unfavorable sex ratios (those featuring more same-sex than opposite-sex individuals) led heterosexual people to diversify financial resources less and instead concentrate investment in high-risk/high-return options when making lottery, stock-pool, retirement-account, and research-funding decisions. These studies shed light on a key process by which people manage risks to mating success implied by unfavorable interpersonal environments. These choice patterns have important implications for mating behavior as well as other everyday forms of decision making. © The Author(s) 2016.

The genetic basis for fruit odor discrimination in Rhagoletis flies and its significance for sympatric host shifts.

PubMed

Dambroski, Hattie R; Linn, Charles; Berlocher, Stewart H; Forbes, Andrew A; Roelofs, Wendell; Feder, Jeffrey L

2005-09-01

Rhagoletis pomonella (Diptera: Tephritidae) use volatile compounds emitted from the surface of ripening fruit as important chemosensory cues for recognizing and distinguishing among alternative host plants. Host choice is of evolutionary significance in Rhagoletis because these flies mate on or near the fruit of their respective host plants. Differences in host choice based on fruit odor discrimination therefore result in differential mate choice and prezygotic reproductive isolation, facilitating sympatric speciation in the absence of geographic isolation. We test for a genetic basis for host fruit odor discrimination through an analysis of F2 and backcross hybrids constructed between apple-, hawthorn-, and flowering dogwood-infesting Rhagoletis flies. We recovered a significant proportion (30-65%) of parental apple, hawthorn, and dogwood fly response phenotypes in F2 hybrids, despite the general failure of F1 hybrids to reach odor source spheres. Segregation patterns in F2 and backcross hybrids suggest that only a modest number of allelic differences at a few loci may underlie host fruit odor discrimination. In addition, a strong bias was observed for F2 and backcross flies to orient to the natal fruit blend of their maternal grandmother, implying the existence of cytonuclear gene interactions. We explore the implications of our findings for the evolutionary dynamics of sympatric host race formation and speciation.

Mechanisms and Evidence of Genital Coevolution: The Roles of Natural Selection, Mate Choice, and Sexual Conflict.

PubMed

Brennan, Patricia L R; Prum, Richard O

2015-07-01

Genital coevolution between the sexes is expected to be common because of the direct interaction between male and female genitalia during copulation. Here we review the diverse mechanisms of genital coevolution that include natural selection, female mate choice, male-male competition, and how their interactions generate sexual conflict that can lead to sexually antagonistic coevolution. Natural selection on genital morphology will result in size coevolution to allow for copulation to be mechanically possible, even as other features of genitalia may reflect the action of other mechanisms of selection. Genital coevolution is explicitly predicted by at least three mechanisms of genital evolution: lock and key to prevent hybridization, female choice, and sexual conflict. Although some good examples exist in support of each of these mechanisms, more data on quantitative female genital variation and studies of functional morphology during copulation are needed to understand more general patterns. A combination of different approaches is required to continue to advance our understanding of genital coevolution. Knowledge of the ecology and behavior of the studied species combined with functional morphology, quantitative morphological tools, experimental manipulation, and experimental evolution have been provided in the best-studied species, all of which are invertebrates. Therefore, attention to vertebrates in any of these areas is badly needed. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

Learning and discrimination of cuticular hydrocarbons in a social insect

PubMed Central

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

Homosexual mating preferences from an evolutionary perspective: sexual selection theory revisited.

PubMed

Gobrogge, Kyle L; Perkins, Patrick S; Baker, Jessica H; Balcer, Kristen D; Breedlove, S Marc; Klump, Kelly L

2007-10-01

Studies in evolutionary psychology and sexual selection theory show that heterosexual men prefer younger mating partners than heterosexual women in order to ensure reproductive success. However, previous research has generally not examined differences in mating preferences as a function of sexual orientation or the type of relationship sought in naturalistic settings. Given that homosexual men seek partners for reasons other than procreation, they may exhibit different mating preferences than their heterosexual counterparts. Moreover, mating preferences may show important differences depending on whether an individual is seeking a long-term versus a short-term relationship. The purpose of the present study was to examine these issues by comparing partner preferences in terms of age and relationship type between homosexual and heterosexual men placing internet personal advertisements. Participants included 439 homosexual and 365 heterosexual men who placed internet ads in the U.S. or Canada. Ads were coded for the participant's age, relationship type (longer-term or short-term sexual encounter) sought, and partner age preferences. Significantly more homosexual than heterosexual men sought sexual encounters, although men (regardless of sexual orientation) seeking sexual encounters preferred a significantly wider age range of partners than men seeking longer-term relationships. These findings suggest that partner preferences are independent of evolutionary drives to procreate, since both types of men preferred similar ages in their partners. In addition, they highlight the importance of examining relationship type in evolutionary studies of mating preferences, as men's partner preferences show important differences depending upon the type of relationship sought.

Socially transmitted mate preferences in a monogamous bird: a non-genetic mechanism of sexual selection.

PubMed

Swaddle, John P; Cathey, Mark G; Correll, Maureen; Hodkinson, Brendan P

2005-05-22

There is increasing evidence that animals can acquire mate preferences through the use of public information, notably by observing (and copying) the mate preferences of others in the population. If females acquire preferences through social mechanisms, sexual selection could act very rapidly to spread the preference and drive elaboration of the preferred trait(s). Although there are reports of 'mate-choice copying' in polygynous species, there is no clear evidence for this process in monogamous species. Here, we investigated whether adult female zebra finches Taeniopygia guttata can socially acquire sexual preferences for individual males and, in a separate study, for a generalized trait (coloured leg bands) of males. In both studies, test females observed males in two simultaneous conditions: a ('chosen') mixed-sex situation in which a male was paired with a (model) female, and a ('unchosen') same-sex situation in which a male was paired with another male. In the first experiment, after two weeks of females observing males, test females significantly preferred individual males who had been paired with another female (i.e. chosen males). In the second experiment, test females significantly preferred novel males that were wearing the same leg band colour as the apparently chosen males. Our findings are consistent with the conclusion that female zebra finches' mate preferences are altered by public information. Our study implies that mate preferences can spread rapidly through populations by social mechanisms, affecting the strength of sexual selection in a monogamous species.

The evolution of phenotypes and genetic parameters under preferential mating

PubMed Central

Roff, Derek A; Fairbairn, Daphne J

2014-01-01

This article extends and adds more realism to Lande's analytical model for evolution under mate choice by using individual-based simulations in which females sample a finite number of males and the genetic architecture of the preference and preferred trait evolves. The simulations show that the equilibrium heritabilities of the preference and preferred trait and the genetic correlation between them (rG), depend critically on aspects of the mating system (the preference function, mode of mate choice, choosiness, and number of potential mates sampled), the presence or absence of natural selection on the preferred trait, and the initial genetic parameters. Under some parameter combinations, preferential mating increased the heritability of the preferred trait, providing a possible resolution for the lek paradox. The Kirkpatrick–Barton approximation for rG proved to be biased downward, but the realized genetic correlations were also low, generally <0.2. Such low values of rG indicate that coevolution of the preference and preferred trait is likely to be very slow and subject to significant stochastic variation. Lande's model accurately predicted the incidence of runaway selection in the simulations, except where preferences were relative and the preferred trait was subject to natural selection. In these cases, runaways were over- or underestimated, depending on the number of males sampled. We conclude that rapid coevolution of preferences and preferred traits is unlikely in natural populations, but that the parameter combinations most conducive to it are most likely to occur in lekking species. PMID:25077025

Conspicuous female ornamentation and tests of male mate preference in threespine sticklebacks (Gasterosteus aculeatus).

PubMed

Wright, Daniel Shane; Pierotti, Michele E R; Rundle, Howard D; McKinnon, Jeffrey S

2015-01-01

Sexual selection drives the evolution of exaggerated male ornaments in many animal species. Female ornamentation is now acknowledged also to be common but is generally less well understood. One example is the recently documented red female throat coloration in some threespine stickleback (Gasterosteus aculeatus) populations. Although female sticklebacks often exhibit a preference for red male throat coloration, the possibility of sexual selection on female coloration has been little studied. Using sequential and simultaneous mate choice trials, we examined male mate preferences for female throat color, as well as pelvic spine color and standard length, using wild-captured threespine sticklebacks from the Little Campbell River, British Columbia. In a multivariate analysis, we found no evidence for a population-level mate preference in males, suggesting the absence of directional sexual selection on these traits arising from male mate choice. Significant variation was detected among males in their preference functions, but this appeared to arise from differences in their mean responsiveness across mating trials and not from variation in the strength (i.e., slope) of their preference, suggesting the absence of individual-level preferences as well. When presented with conspecific intruder males, male response decreased as intruder red throat coloration increased, suggesting that males can discriminate color and other aspects of phenotype in our experiment and that males may use these traits in intrasexual interactions. The results presented here are the first to explicitly address male preference for female throat color in threespine sticklebacks.

Conspicuous Female Ornamentation and Tests of Male Mate Preference in Threespine Sticklebacks (Gasterosteus aculeatus)

PubMed Central

Wright, Daniel Shane; Pierotti, Michele E. R.; Rundle, Howard D.; McKinnon, Jeffrey S.

2015-01-01

Sexual selection drives the evolution of exaggerated male ornaments in many animal species. Female ornamentation is now acknowledged also to be common but is generally less well understood. One example is the recently documented red female throat coloration in some threespine stickleback (Gasterosteus aculeatus) populations. Although female sticklebacks often exhibit a preference for red male throat coloration, the possibility of sexual selection on female coloration has been little studied. Using sequential and simultaneous mate choice trials, we examined male mate preferences for female throat color, as well as pelvic spine color and standard length, using wild-captured threespine sticklebacks from the Little Campbell River, British Columbia. In a multivariate analysis, we found no evidence for a population-level mate preference in males, suggesting the absence of directional sexual selection on these traits arising from male mate choice. Significant variation was detected among males in their preference functions, but this appeared to arise from differences in their mean responsiveness across mating trials and not from variation in the strength (i.e., slope) of their preference, suggesting the absence of individual-level preferences as well. When presented with conspecific intruder males, male response decreased as intruder red throat coloration increased, suggesting that males can discriminate color and other aspects of phenotype in our experiment and that males may use these traits in intrasexual interactions. The results presented here are the first to explicitly address male preference for female throat color in threespine sticklebacks. PMID:25806520

Knockout mutations of insulin-like peptide genes enhance sexual receptivity in Drosophila virgin females.

PubMed

Watanabe, Kazuki; Sakai, Takaomi

2016-01-01

In the fruitfly Drosophila melanogaster, females take the initiative to mate successfully because they decide whether to mate or not. However, little is known about the molecular and neuronal mechanisms regulating sexual receptivity in virgin females. Genetic tools available in Drosophila are useful for identifying molecules and neural circuits involved in the regulation of sexual receptivity. We previously demonstrated that insulin-producing cells (IPCs) in the female brain are critical to the regulation of female sexual receptivity. Ablation and inactivation of IPCs enhance female sexual receptivity, suggesting that neurosecretion from IPCs inhibits female sexual receptivity. IPCs produce and release insulin-like peptides (Ilps) that modulate various biological processes such as metabolism, growth, lifespan and behaviors. Here, we report a novel role of the Ilps in sexual behavior in Drosophila virgin females. Compared with wild-type females, females with knockout mutations of Ilps showed a high mating success rate toward wild-type males, whereas wild-type males courted wild-type and Ilp-knockout females to the same extent. Wild-type receptive females retard their movement during male courtship and this reduced female mobility allows males to copulate. Thus, it was anticipated that knockout mutations of Ilps would reduce general locomotion. However, the locomotor activity in Ilp-knockout females was significantly higher than that in wild-type females. Thus, our findings indicate that the high mating success rate in Ilp-knockout females is caused by their enhanced sexual receptivity, but not by improvement of their sex appeal or by general sluggishness.

Nonlinear and correlational sexual selection on 'honest' female ornamentation.

PubMed Central

LeBas, Natasha R; Hockham, Leon R; Ritchie, Michael G

2003-01-01

Female ornamentation has long been overlooked because of the greater prevalence of elaborate displays in males. However, the circumstances under which females would benefit from honestly signalling their quality are limited. Females are not expected to invest in ornamentation unless the fitness benefits of the ornament exceed those derived from investing the resources directly into offspring. It has been proposed that when females gain direct benefits from mating, females may instead be selected for ornamentation that deceives males about their reproductive state. In the empidid dance flies, males frequently provide nuptial gifts and it is usually only the female that is ornamented. Female traits in empidids, such as abdominal sacs and enlarged pinnate leg scales, have been proposed to 'deceive' males into matings by disguising egg maturity. We quantified sexual selection in the dance fly Rhamphomyia tarsata and found escalating, quadratic selection on pinnate scales and that pinnate scales honestly reflect female fecundity. Mated females had a larger total number and more mature eggs than unmated females, highlighting a potential benefit rather than a cost of male mate choice. We also show correlational selection on female pinnate scales and fecundity. Correlational selection, equivalent investment patterns or increased nutrition from nuptial gifts may all maintain honesty in female ornamentation. PMID:14561280

The contrasting role of male relatedness in different mechanisms of sexual selection in red junglefowl

PubMed Central

Tan, Cedric Kai Wei; Doyle, Philippa; Bagshaw, Emma; Richardson, David S.; Wigby, Stuart; Pizzari, Tommaso

2017-01-01

In structured populations, competition for reproductive opportunities should be relaxed among related males. The few tests of this prediction often neglect the fact that sexual selection acts through multiple mechanisms, both before and after mating. We performed experiments to study the role of within‐group male relatedness across pre‐ and postcopulatory mechanisms of sexual selection in social groups of red junglefowl, Gallus gallus, in which two related males and one unrelated male competed over females unrelated to all the males. We confirm theoretical expectations that, after controlling for male social status, competition over mating was reduced among related males. However, this effect was contrasted by other sexual selection mechanisms. First, females biased male mating in favor of the unrelated male, and might also favor his inseminations after mating. Second, males invested more—rather than fewer—sperm in postcopulatory competition with relatives. A number of factors may contribute to explain this counterintuitive pattern of sperm allocation, including trade‐offs between male investment in pre‐ versus postcopulatory competition, differences in the relative relatedness of pre‐ versus postcopulatory competitors, and female bias in sperm utilization in response to male relatedness. Collectively, these results reveal that within‐group male relatedness may have contrasting effects in different mechanisms of sexual selection. PMID:27925168

Populations of weedy crop–wild hybrid beets show contrasting variation in mating system and population genetic structure

PubMed Central

Arnaud, Jean-François; Fénart, Stéphane; Cordellier, Mathilde; Cuguen, Joël

2010-01-01

Reproductive traits are key parameters for the evolution of invasiveness in weedy crop–wild hybrids. In Beta vulgaris, cultivated beets hybridize with their wild relatives in the seed production areas, giving rise to crop–wild hybrid weed beets. We investigated the genetic structure, the variation in first-year flowering and the variation in mating system among weed beet populations occurring within sugar beet production fields. No spatial genetic structure was found for first-year populations composed of F1 crop–wild hybrid beets. In contrast, populations composed of backcrossed weed beets emerging from the seed bank showed a strong isolation-by-distance pattern. Whereas gametophytic self-incompatibility prevents selfing in wild beet populations, all studied weed beet populations had a mixed-mating system, plausibly because of the introgression of the crop-derived Sf gene that disrupts self-incompatibility. No significant relationship between outcrossing rate and local weed beet density was found, suggesting no trends for a shift in the mating system because of environmental effects. We further reveal that increased invasiveness of weed beets may stem from positive selection on first-year flowering induction depending on the B gene inherited from the wild. Finally, we discuss the practical and applied consequences of our findings for crop-weed management. PMID:25567926

The effects of quantitative fecundity in the haploid stage on reproductive success and diploid fitness in the aquatic peat moss Sphagnum macrophyllum

PubMed Central

Johnson, M G; Shaw, A J

2016-01-01

A major question in evolutionary biology is how mating patterns affect the fitness of offspring. However, in animals and seed plants it is virtually impossible to investigate the effects of specific gamete genotypes. In bryophytes, haploid gametophytes grow via clonal propagation and produce millions of genetically identical gametes throughout a population. The main goal of this research was to test whether gamete identity has an effect on the fitness of their diploid offspring in a population of the aquatic peat moss Sphagnum macrophyllum. We observed a heavily male-biased sex ratio in gametophyte plants (ramets) and in multilocus microsatellite genotypes (genets). There was a steeper relationship between mating success (number of different haploid mates) and fecundity (number of diploid offspring) for male genets compared with female genets. At the sporophyte level, we observed a weak effect of inbreeding on offspring fitness, but no effect of brood size (number of sporophytes per maternal ramet). Instead, the identities of the haploid male and haploid female parents were significant contributors to variance in fitness of sporophyte offspring in the population. Our results suggest that intrasexual gametophyte/gamete competition may play a role in determining mating success in this population. PMID:26905464

The effects of quantitative fecundity in the haploid stage on reproductive success and diploid fitness in the aquatic peat moss Sphagnum macrophyllum.

PubMed

Johnson, M G; Shaw, A J

2016-06-01

A major question in evolutionary biology is how mating patterns affect the fitness of offspring. However, in animals and seed plants it is virtually impossible to investigate the effects of specific gamete genotypes. In bryophytes, haploid gametophytes grow via clonal propagation and produce millions of genetically identical gametes throughout a population. The main goal of this research was to test whether gamete identity has an effect on the fitness of their diploid offspring in a population of the aquatic peat moss Sphagnum macrophyllum. We observed a heavily male-biased sex ratio in gametophyte plants (ramets) and in multilocus microsatellite genotypes (genets). There was a steeper relationship between mating success (number of different haploid mates) and fecundity (number of diploid offspring) for male genets compared with female genets. At the sporophyte level, we observed a weak effect of inbreeding on offspring fitness, but no effect of brood size (number of sporophytes per maternal ramet). Instead, the identities of the haploid male and haploid female parents were significant contributors to variance in fitness of sporophyte offspring in the population. Our results suggest that intrasexual gametophyte/gamete competition may play a role in determining mating success in this population.

Extra-Pair Mating and Evolution of Cooperative Neighbourhoods

PubMed Central

Eliassen, Sigrunn; Jørgensen, Christian

2014-01-01

A striking but unexplained pattern in biology is the promiscuous mating behaviour in socially monogamous species. Although females commonly solicit extra-pair copulations, the adaptive reason has remained elusive. We use evolutionary modelling of breeding ecology to show that females benefit because extra-pair paternity incentivizes males to shift focus from a single brood towards the entire neighbourhood, as they are likely to have offspring there. Male-male cooperation towards public goods and dear enemy effects of reduced territorial aggression evolve from selfish interests, and lead to safer and more productive neighbourhoods. The mechanism provides adaptive explanations for the common empirical observations that females engage in extra-pair copulations, that neighbours dominate as extra-pair sires, and that extra-pair mating correlates with predation mortality and breeding density. The models predict cooperative behaviours at breeding sites where males cooperate more towards public goods than females. Where maternity certainty makes females care for offspring at home, paternity uncertainty and a potential for offspring in several broods make males invest in communal benefits and public goods. The models further predict that benefits of extra-pair mating affect whole nests or neighbourhoods, and that cuckolding males are often cuckolded themselves. Derived from ecological mechanisms, these new perspectives point towards the evolution of sociality in birds, with relevance also for mammals and primates including humans. PMID:24987839

Odour-based discrimination of similarity at the major histocompatibility complex in birds.

PubMed

Leclaire, Sarah; Strandh, Maria; Mardon, Jérôme; Westerdahl, Helena; Bonadonna, Francesco

2017-01-11

Many animals are known to preferentially mate with partners that are dissimilar at the major histocompatibility complex (MHC) in order to maximize the antigen binding repertoire (or disease resistance) in their offspring. Although several mammals, fish or lizards use odour cues to assess MHC similarity with potential partners, the ability of birds to assess MHC similarity using olfactory cues has not yet been explored. Here we used a behavioural binary choice test and high-throughput-sequencing of MHC class IIB to determine whether blue petrels can discriminate MHC similarity based on odour cues alone. Blue petrels are seabirds with particularly good sense of smell, they have a reciprocal mate choice and are known to preferentially mate with MHC-dissimilar partners. Incubating males preferentially approached the odour of the more MHC-dissimilar female, whereas incubating females showed opposite preferences. Given their mating pattern, females were, however, expected to show preference for the odour of the more MHC-dissimilar male. Further studies are needed to determine whether, as in women and female mice, the preference varies with the reproductive cycle in blue petrel females. Our results provide the first evidence that birds can use odour cues only to assess MHC dissimilarity. © 2017 The Author(s).

Individual differences in boldness influence patterns of social interactions and the transmission of cuticular bacteria among group-mates

PubMed Central

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

Individual differences in boldness influence patterns of social interactions and the transmission of cuticular bacteria among group-mates.

PubMed

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).

Inbreeding depresses sperm competitiveness, but not fertilization or mating success in male Tribolium castaneum

PubMed Central

Michalczyk, Łukasz; Martin, Oliver Y.; Millard, Anna L.; Emerson, Brent C.; Gage, Matthew J. G.

2010-01-01

As populations decline to levels where reproduction among close genetic relatives becomes more probable, subsequent increases in homozygous recessive deleterious expression and/or loss of heterozygote advantage can lead to inbreeding depression. Here, we measure how inbreeding across replicate lines of the flour beetle Tribolium castaneum impacts on male reproductive fitness in the absence or presence of male–male competition. Effects on male evolution from mating pattern were removed by enforcing monogamous mating throughout. After inbreeding across eight generations, we found that male fertility in the absence of competition was unaffected. However, we found significant inbreeding depression of sperm competitiveness: non-inbred males won 57 per cent of fertilizations in competition, while inbred equivalents only sired 42 per cent. We also found that the P2 ‘offence’ role in sperm competition was significantly more depressed under inbreeding than sperm ‘defence’ (P1). Mating behaviour did not explain these differences, and there was no difference in the viability of offspring sired by inbred or non-inbred males. Sperm length variation was significantly greater in the ejaculates of inbred males. Our results show that male ability to achieve normal fertilization success was not depressed under strong inbreeding, but that inbreeding depression in these traits occurred when conditions of sperm competition were generated. PMID:20554548

Inbreeding depresses sperm competitiveness, but not fertilization or mating success in male Tribolium castaneum.

PubMed

Michalczyk, Lukasz; Martin, Oliver Y; Millard, Anna L; Emerson, Brent C; Gage, Matthew J G

2010-11-22

As populations decline to levels where reproduction among close genetic relatives becomes more probable, subsequent increases in homozygous recessive deleterious expression and/or loss of heterozygote advantage can lead to inbreeding depression. Here, we measure how inbreeding across replicate lines of the flour beetle Tribolium castaneum impacts on male reproductive fitness in the absence or presence of male-male competition. Effects on male evolution from mating pattern were removed by enforcing monogamous mating throughout. After inbreeding across eight generations, we found that male fertility in the absence of competition was unaffected. However, we found significant inbreeding depression of sperm competitiveness: non-inbred males won 57 per cent of fertilizations in competition, while inbred equivalents only sired 42 per cent. We also found that the P(2) 'offence' role in sperm competition was significantly more depressed under inbreeding than sperm 'defence' (P(1)). Mating behaviour did not explain these differences, and there was no difference in the viability of offspring sired by inbred or non-inbred males. Sperm length variation was significantly greater in the ejaculates of inbred males. Our results show that male ability to achieve normal fertilization success was not depressed under strong inbreeding, but that inbreeding depression in these traits occurred when conditions of sperm competition were generated.

Mating systems and sexual selection in male-pregnant pipefishes and seahorses: insights from microsatellite-based studies of maternity.

PubMed

Jones, A G; Avise, J C

2001-01-01

In pipefishes and seahorses (family Syngnathidae), the males provide all postzygotic care of offspring by brooding embryos on their ventral surfaces. In some species, this phenomenon of male "pregnancy" results in a reversal of the usual direction of sexual selection, such that females compete more than males for access to mates, and secondary sexual characteristics evolve in females. Thus the syngnathids can provide critical tests of theories related to the evolution of sex differences and sexual selection. Microsatellite-based studies of the genetic mating systems of several species of pipefishes and seahorses have provided insights into important aspects of the natural history and evolution of these fishes. First, males of species with completely enclosed pouches have complete confidence of paternity, as might be predicted from parental investment theory for species in which males invest so heavily in offspring. Second, a wide range of genetic mating systems have been documented in nature, including genetic monogamy in a seahorse, polygynandry in two species of pipefish, and polyandry in a third pipefish species. The genetic mating systems appear to be causally related to the intensity of sexual selection, with secondary sex characters evolving most often in females of the more polyandrous species. Third, genetic studies of captive-breeding pipefish suggest that the sexual selection gradient (or Bateman gradient) may be a substantially better method for characterizing the mating system than previously available techniques. Finally, these genetic studies of syngnathid mating systems have led to some general insights into the occurrence of clustered mutations at microsatellite loci, the utility of linked loci in studies of parentage, and the use of parentage data for direct estimation of adult population size.

Correlates of genetic monogamy in socially monogamous mammals: insights from Azara's owl monkeys

PubMed Central

Huck, Maren; Fernandez-Duque, Eduardo; Babb, Paul; Schurr, Theodore

2014-01-01

Understanding the evolution of mating systems, a central topic in evolutionary biology for more than 50 years, requires examining the genetic consequences of mating and the relationships between social systems and mating systems. Among pair-living mammals, where genetic monogamy is extremely rare, the extent of extra-group paternity rates has been associated with male participation in infant care, strength of the pair bond and length of the breeding season. This study evaluated the relationship between two of those factors and the genetic mating system of socially monogamous mammals, testing predictions that male care and strength of pair bond would be negatively correlated with rates of extra-pair paternity (EPP). Autosomal microsatellite analyses provide evidence for genetic monogamy in a pair-living primate with bi-parental care, the Azara's owl monkey (Aotus azarae). A phylogenetically corrected generalized least square analysis was used to relate male care and strength of the pair bond to their genetic mating system (i.e. proportions of EPP) in 15 socially monogamous mammalian species. The intensity of male care was correlated with EPP rates in mammals, while strength of pair bond failed to reach statistical significance. Our analyses show that, once social monogamy has evolved, paternal care, and potentially also close bonds, may facilitate the evolution of genetic monogamy. PMID:24648230

Correlates of genetic monogamy in socially monogamous mammals: insights from Azara's owl monkeys.

PubMed

Huck, Maren; Fernandez-Duque, Eduardo; Babb, Paul; Schurr, Theodore

2014-05-07

Understanding the evolution of mating systems, a central topic in evolutionary biology for more than 50 years, requires examining the genetic consequences of mating and the relationships between social systems and mating systems. Among pair-living mammals, where genetic monogamy is extremely rare, the extent of extra-group paternity rates has been associated with male participation in infant care, strength of the pair bond and length of the breeding season. This study evaluated the relationship between two of those factors and the genetic mating system of socially monogamous mammals, testing predictions that male care and strength of pair bond would be negatively correlated with rates of extra-pair paternity (EPP). Autosomal microsatellite analyses provide evidence for genetic monogamy in a pair-living primate with bi-parental care, the Azara's owl monkey (Aotus azarae). A phylogenetically corrected generalized least square analysis was used to relate male care and strength of the pair bond to their genetic mating system (i.e. proportions of EPP) in 15 socially monogamous mammalian species. The intensity of male care was correlated with EPP rates in mammals, while strength of pair bond failed to reach statistical significance. Our analyses show that, once social monogamy has evolved, paternal care, and potentially also close bonds, may facilitate the evolution of genetic monogamy.

Discrete two-sex models of population dynamics: On modelling the mating function

NASA Astrophysics Data System (ADS)

Bessa-Gomes, Carmen; Legendre, Stéphane; Clobert, Jean

2010-09-01

Although sexual reproduction has long been a central subject of theoretical ecology, until recently its consequences for population dynamics were largely overlooked. This is now changing, and many studies have addressed this issue, showing that when the mating system is taken into account, the population dynamics depends on the relative abundance of males and females, and is non-linear. Moreover, sexual reproduction increases the extinction risk, namely due to the Allee effect. Nevertheless, different studies have identified diverse potential consequences, depending on the choice of mating function. In this study, we investigate the consequences of three alternative mating functions that are frequently used in discrete population models: the minimum; the harmonic mean; and the modified harmonic mean. We consider their consequences at three levels: on the probability that females will breed; on the presence and intensity of the Allee effect; and on the extinction risk. When we consider the harmonic mean, the number of times the individuals of the least abundant sex mate exceeds their mating potential, which implies that with variable sex-ratios the potential reproductive rate is no longer under the modeller's control. Consequently, the female breeding probability exceeds 1 whenever the sex-ratio is male-biased, which constitutes an obvious problem. The use of the harmonic mean is thus only justified if we think that this parameter should be re-defined in order to represent the females' breeding rate and the fact that females may reproduce more than once per breeding season. This phenomenon buffers the Allee effect, and reduces the extinction risk. However, when we consider birth-pulse populations, such a phenomenon is implausible because the number of times females can reproduce per birth season is limited. In general, the minimum or modified harmonic mean mating functions seem to be more suitable for assessing the impact of mating systems on population dynamics.

Mate choice, sexual imprinting, and speciation: a test of a one-allele isolating mechanism in sympatric sticklebacks.

PubMed

Albert, Arianne Y K

2005-04-01

One-allele isolating mechanisms should make the evolution of reproductive isolation between potentially hybridizing taxa easier than two-allele mechanisms, but the generality of one-allele mechanisms in nature has yet to be established. A potentially important one-allele mechanism is sexual imprinting, where the mate preferences of individuals are based on the phenotype of their parents. Here I test the possibility that sexual imprinting promotes reproductive isolation using sympatric species of threespine sticklebacks (Gasterosteus aculeatus). Sympatric species of sticklebacks consist of large benthic species and small limnetic species that are reproductively isolated and adapted to feeding in different environments. I fostered families of F1 hybrids between the species to males of both species. Preferences of these fostered females for males of either type revealed little or no effect of sexual imprinting on assortative mating. However, F1 females showed preferences for males that were similar to themselves in length, suggesting that size-assortative mating may be more important than sexual imprinting for promoting reproductive isolation between species pairs of threespine sticklebacks.

Multiple Convergent Origins of Workerlessness and Inbreeding in the Socially Parasitic Ant Genus Myrmoxenus.

PubMed

Heinze, Jürgen; Buschinger, Alfred; Poettinger, Theo; Suefuji, Masaki

2015-01-01

The socially parasitic ant genus Myrmoxenus varies strongly in fundamental life history traits, such as queen-worker ratio, the timing of sexual production, and mating behavior. Myrmoxenus queens generally take over nests of Temnothorax ants, kill the resident queen by throttling, and force the workers to take care of the social parasite's brood. Young queens of M. ravouxi and other species produce large numbers of workers, which during "slave-raids" pillage host pupae from neighboring Temnothorax colonies to increase the workforce in their own nests. Other species, such as M. corsicus, have lost caste polyphenism and rear only male and female sexual offspring. Using sequences of the genes CO I/CO II and wingless we reconstruct the phylogeny of Myrmoxenus and document that the worker caste was lost convergently at least three times. Furthermore, mating in the nest and inbreeding obviously also evolved in parallel from ancestors whose sexuals presumably mated during nuptial flights. Myrmoxenus might thus provide a suitable model to investigate caste differentiation and the plasticity of mating behavior in Hymenoptera.

Polymorphism at a mimicry supergene maintained by opposing frequency-dependent selection pressures.

PubMed

Chouteau, Mathieu; Llaurens, Violaine; Piron-Prunier, Florence; Joron, Mathieu

2017-08-01

Explaining the maintenance of adaptive diversity within populations is a long-standing goal in evolutionary biology, with important implications for conservation, medicine, and agriculture. Adaptation often leads to the fixation of beneficial alleles, and therefore it erodes local diversity so that understanding the coexistence of multiple adaptive phenotypes requires deciphering the ecological mechanisms that determine their respective benefits. Here, we show how antagonistic frequency-dependent selection (FDS), generated by natural and sexual selection acting on the same trait, maintains mimicry polymorphism in the toxic butterfly Heliconius numata Positive FDS imposed by predators on mimetic signals favors the fixation of the most abundant and best-protected wing-pattern morph, thereby limiting polymorphism. However, by using mate-choice experiments, we reveal disassortative mate preferences of the different wing-pattern morphs. The resulting negative FDS on wing-pattern alleles is consistent with the excess of heterozygote genotypes at the supergene locus controlling wing-pattern variation in natural populations of H. numata The combined effect of positive and negative FDS on visual signals is sufficient to maintain a diversity of morphs displaying accurate mimicry with other local prey, although some of the forms only provide moderate protection against predators. Our findings help understand how alternative adaptive phenotypes can be maintained within populations and emphasize the need to investigate interactions between selective pressures in other cases of puzzling adaptive polymorphism.

Polymorphism at a mimicry supergene maintained by opposing frequency-dependent selection pressures

PubMed Central

Chouteau, Mathieu; Llaurens, Violaine; Piron-Prunier, Florence; Joron, Mathieu

2017-01-01

Explaining the maintenance of adaptive diversity within populations is a long-standing goal in evolutionary biology, with important implications for conservation, medicine, and agriculture. Adaptation often leads to the fixation of beneficial alleles, and therefore it erodes local diversity so that understanding the coexistence of multiple adaptive phenotypes requires deciphering the ecological mechanisms that determine their respective benefits. Here, we show how antagonistic frequency-dependent selection (FDS), generated by natural and sexual selection acting on the same trait, maintains mimicry polymorphism in the toxic butterfly Heliconius numata. Positive FDS imposed by predators on mimetic signals favors the fixation of the most abundant and best-protected wing-pattern morph, thereby limiting polymorphism. However, by using mate-choice experiments, we reveal disassortative mate preferences of the different wing-pattern morphs. The resulting negative FDS on wing-pattern alleles is consistent with the excess of heterozygote genotypes at the supergene locus controlling wing-pattern variation in natural populations of H. numata. The combined effect of positive and negative FDS on visual signals is sufficient to maintain a diversity of morphs displaying accurate mimicry with other local prey, although some of the forms only provide moderate protection against predators. Our findings help understand how alternative adaptive phenotypes can be maintained within populations and emphasize the need to investigate interactions between selective pressures in other cases of puzzling adaptive polymorphism. PMID:28673971

Role of social interactions in dynamic patterns of resource patches and forager aggregation

PubMed Central

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

Stability and value of male care for offspring: is it worth only half the trouble?

PubMed

Fromhage, Lutz; McNamara, John M; Houston, Alasdair I

2007-06-22

Models of parental investment often assume a trade-off for males between providing care and seeking additional mating opportunities. It is not obvious, however, how such additional matings should be accounted for in a consistent population model, because deserting males might increase their fertilization success at the cost of either caring males, other deserting males or both. Here, we present a game theory model that addresses all of these possibilities in a general way. In contrast to earlier work, we find that the source of deserting males' additional matings is irrelevant to the evolutionary stability of male care. We reject the claim that fitness gains through male care are intrinsically less valuable than those through desertion, and that the former must therefore be down-weighted by 1/2 when compared with the latter.

Sexual cannibalism as a manifestation of sexual conflict.

PubMed

Schneider, Jutta M

2014-09-11

Sexual cannibalism is a well-known example for sexual conflict and has many facets that determine the costs and benefits for the cannibal and the victim. Here, I focus on species in which sexual cannibalism is a general component of a mating system in which males invest maximally in mating with a single (monogyny) or two (bigyny) females. Sexual cannibalism can be a male strategy to maximize paternity and a female strategy to prevent paternity monopolization by any or a particular male. Considerable variation exists between species (1) in the potential of males to monopolize females, and (2) in the success of females in preventing monopolization by males. This opens up exciting future possibilities to investigate sexually antagonistic coevolution in a largely unstudied mating system. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

Mating system and gene flow in the red seaweed Gracilaria gracilis: effect of haploid-diploid life history and intertidal rocky shore landscape on fine-scale genetic structure.

PubMed

Engel, C R; Destombe, C; Valero, M

2004-04-01

The impact of haploid-diploidy and the intertidal landscape on a fine-scale genetic structure was explored in a red seaweed Gracilaria gracilis. The pattern of genetic structure was compared in haploid and diploid stages at a microgeographic scale (< 5 km): a total of 280 haploid and 296 diploid individuals located in six discrete, scattered rock pools were genotyped using seven microsatellite loci. Contrary to the theoretical expectation of predominantly endogamous mating systems in haploid-diploid organisms, G. gracilis showed a clearly allogamous mating system. Although within-population allele frequencies were similar between haploids and diploids, genetic differentiation among haploids was more than twice that of diploids, suggesting that there may be a lag between migration and (local) breeding due to the long generation times in G. gracilis. Weak, but significant, population differentiation was detected in both haploids and diploids and varied with landscape features, and not with geographic distance. Using an assignment test, we establish that effective migration rates varied according to height on the shore. In this intertidal species, biased spore dispersal may occur during the transport of spores and gametes at low tide when small streams flow from high- to lower-shore pools. The longevity of both haploid and diploid free-living stages and the long generation times typical of G. gracilis populations may promote the observed pattern of high genetic diversity within populations relative to that among populations.

On the role of individual differences in female odor and ultrasonic vocalizations for male's choice of partner.

PubMed

Snoeren, Eelke M; Helander, Lars R; Iversen, Eric E; Ågmo, Anders

2014-06-10

Intrasexual competition for access to a female mate is believed to be unusual in wild male rats, which suggests that female choosiness could be important. Even if competition is unusual, males still have to inevitably approach one partner first for copulation. In females, it has been shown that females spend longer time with one male compared to the others when tested in a multiple partner paradigm. The male mate preference was investigated in this study. In addition, the role of ultrasonic vocalizations (USVs) and female odors in the male's initial choice to approach one female instead of another was studied in this experiment. Male rats could choose between three different sexually receptive females. The experiment started with a 15-minute period with inaccessible females followed by a 15-minute period with accessible females in which the males could copulate with the females of his choice. The results showed that male rats spent more time with the female of 1st entry over the second or third females visited. No differences were found in USV subtype patterns emitted by the different females or the number of sniff episodes towards the different female chambers. Thus, the present experiments did not offer any evidence suggesting that USVs or individual differences in female odors play any role in male mate choice. Other factors that were not investigated in this study might be involved in male mate selection, but it should also be considered that mate selection could be random. Copyright © 2014 Elsevier Inc. All rights reserved.

Postpollination discrimination between self and outcross pollen covaries with the mating system of a self-compatible flowering plant.

PubMed

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.

Socio-sexuality and episodic memory function in women: further evidence of an adaptive "mating mode".

PubMed

Smith, David S; Jones, Benedict C; Allan, Kevin

2013-08-01

The functionalist memory perspective predicts that information of adaptive value may trigger specific processing modes. It was recently demonstrated that women's memory is sensitive to cues of male sexual dimorphism (i.e., masculinity) that convey information of adaptive value for mate choice because they signal health and genetic quality, as well as personality traits important in relationship contexts. Here, we show that individual differences in women's mating strategies predict the effect of facial masculinity cues upon memory, strengthening the case for functional design within memory. Using the revised socio-sexual orientation inventory, Experiment 1 demonstrates that women pursuing a short-term, uncommitted mating strategy have enhanced source memory for men with exaggerated versus reduced masculine facial features, an effect that reverses in women who favor long-term committed relationships. The reversal in the direction of the effect indicates that it does not reflect the sex typicality of male faces per se. The same pattern occurred within women's source memory for women's faces, implying that the memory bias does not reflect the perceived attractiveness of faces per se. In Experiment 2, we reran the experiment using men's faces to establish the reliability of the core finding and replicated Experiment 1's results. Masculinity cues may therefore trigger a specific mode within women's episodic memory. We discuss why this mode may be triggered by female faces and its possible role in mate choice. In so doing, we draw upon the encoding specificity principle and the idea that episodic memory limits the scope of stereotypical inferences about male behavior.

Effect of season on reproductive behaviors and fertilization success in cavies (Cavia aperea).

PubMed

Hribal, Romy; Rübensam, Kathrin; Bernhardt, Sandra; Jewgenow, Katarina; Guenther, Anja

2018-04-05

Finding the optimal timing for breeding is crucial for small mammals to ensure survival and maximize lifetime reproductive success. Species living in temperate regions therefore often restrict breeding to seasons with favorable food and weather conditions. Although caviomorph rodents such as guinea pigs are described as non-seasonal breeders, a series of recent publications has shown seasonal adaptations in litter size, offspring birth mass and maternal investment. Here, we aim to test if seasonal patterns of litter size variation found in earlier studies, are mediated by seasonal differences in female estrus length, fertilization rate and mating behavior. The female estrus period was longer in fall compared to all other seasons (p < 0.001), frequently lasting 7-9 days while estrus in spring usually lasted less than 2 days. In fall, females mated later during estrus (p < 0.001), resulting in reduced fertilization rates (p < 0.001). Fertilization rate was well above 95% in summer while it dropped to less than 85% in fall and winter. While none of the male mating characteristics such as number and duration of copulations differed across seasons, the number of mating bouts was reduced in fall (p = 0.04). Finally, the developmental stages of flushed embryos were more diverse in spring and summer compared to fall and winter. These results suggest that seasonal differences in fertilization rate and quality of implanted embryos are mediated by female estrus length and timing and intensity of mating behavior. Together, these effects contribute to the observed differences in litter size across seasons. Copyright © 2018 Elsevier Inc. All rights reserved.

Male motion coordination in swarming Anopheles gambiae and Anopheles coluzzii

USDA-ARS?s Scientific Manuscript database

The Anopheles gambiae species complex comprises the primary vectors of malaria in much of sub-Saharan Africa; most of the mating in these species occurs in swarms composed almost entirely of males. Intermittent, parallel flight patterns in such swarms have been observed, but a detailed description o...

Frequency-dependent sexual selection.

PubMed

O'Donald, P; Majerus, M E

1988-07-06

Sexual selection by female choice is expected to give rise to a frequency-dependent sexual advantage in favour of preferred male phenotypes: the rarer the preferred phenotypes, the more often they are chosen as mates. This 'rare-male advantage' can maintain a polymorphism when two or more phenotypes are mated preferentially: each phenotype gains an advantage when it is rarer than the others; no preferred phenotype can then be lost from the population. Expression of preference may be complete or partial. In models of complete preference, females with a preference always mate preferentially. Models of partial preference are more realistic: in these models, the probability that a female mates preferentially depends on the frequency with which she encounters the males she prefers. Two different 'encounter models' of partial preference have been derived: the O'Donald model and the Charlesworth model. The encounter models contain the complete preference model as a limiting case. In this paper, the Charlesworth model is generalized to allow for female preference of more than one male phenotype. Levels of frequency dependence can then be compared in the O'Donald and Charlesworth models. The complete preference model and both encounter models are formulated in the same genetical terms of preferences for dominant and recessive male phenotypes. Polymorphic equilibria and conditions for stability are derived for each of the three models. The models are then fitted to data of frequencies of matings observed in experiments with the two-spot ladybird. The complete preference model gives as good a fit as the encounter models to the data of these and other experiments. The O'Donald and Charlesworth encounter models are shown to produce a very similar frequency-dependent relation. Generally, as females become less choosy, they express their preference with more dependence on male frequency, whereas the resulting selection of the males becomes less frequency dependent. More choosy females are more constant in expressing their preference, producing greater frequency dependence in the selection of the males.

A Rare-Male Advantage in the Housefly Induced by Wing Clipping and Some General Considerations for Drosophila

PubMed Central

Bryant, Edwin H.; Kence, Aykut; Kimball, Kay T.

1980-01-01

Multiple-choice crosses among five geographic strains of the housefly, Musca domestica L., were carried out in equal (10:10) and low-frequency (4:16) ratios. Initially, a low-frequency-male mating advantage was apparent, but further analyses related this minority advantage to a reduction of male mating success during marking by wing clipping. When there are fluctuating differences in the level of sexual vigor between competing male types over replicate trials of a cross, a mating advantage will accrue to the minority type. Even if males from the two competing strains are equally vigorous, such fluctuating differences will occur during sampling of flies. Harming the flies during marking will serve to enhance this effect and make significant departures toward greater mating success of rare males highly likely. This statistical bias in favor of minority males was substantiated in simulations of the Kence-Bryant model of mating success and compared with our results of a minority advantage in the housefly and with published results of a minority advantage in Drosophila. Our evidence, though circumstantial, that an advantage to minority males could have been induced by such an experimental bias suggests that a re-examination of existing data, as well as new experimentation, is necessary to discern whether or not a real rare-male advantage exists. PMID:7262546

High estradiol and low progesterone are associated with high assertiveness in women.

PubMed

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.

Sociosexuality from Argentina to Zimbabwe: a 48-nation study of sex, culture, and strategies of human mating.

PubMed

Schmitt, David P

2005-04-01

The Sociosexual Orientation Inventory (SOI; Simpson & Gangestad 1991) is a self-report measure of individual differences in human mating strategies. Low SOI scores signify that a person is sociosexually restricted, or follows a more monogamous mating strategy. High SOI scores indicate that an individual is unrestricted, or has a more promiscuous mating strategy. As part of the International Sexuality Description Project (ISDP), the SOI was translated from English into 25 additional languages and administered to a total sample of 14,059 people across 48 nations. Responses to the SOI were used to address four main issues. First, the psychometric properties of the SOI were examined in cross-cultural perspective. The SOI possessed adequate reliability and validity both within and across a diverse range of modem cultures. Second, theories concerning the systematic distribution of sociosexuality across cultures were evaluated. Both operational sex ratios and reproductively demanding environments related in evolutionary-predicted ways to national levels of sociosexuality. Third, sex differences in sociosexuality were generally large and demonstrated cross-cultural universality across the 48 nations of the ISDP, confirming several evolutionary theories of human mating. Fourth, sex differences in sociosexuality were significantly larger when reproductive environments were demanding but were reduced to more moderate levels in cultures with more political and economic gender equality. Implications for evolutionary and social role theories of human sexuality are discussed.

Mating system and ploidy influence levels of inbreeding depression in Clarkia (Onagraceae).

PubMed

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.

Phenotypic plasticity in sex allocation for a simultaneously hermaphroditic coral reef fish

NASA Astrophysics Data System (ADS)

Hart, M. K.; Svoboda, A.; Mancilla Cortez, D.

2011-06-01

Phenotypic plasticity can facilitate reproductive strategies that maximize mating success in variable environments and lead to differences in sex allocation among populations. For simultaneous hermaphrodites with sperm competition, including Serranus tortugarum a small coral reef fish, proportional male allocation (testis in total gonad) is often greater where local density or mating group size is higher. We tested whether S. tortugarum reduced male allocation when transplanted from a higher density site to a lower density site. After 4 months, transplants mirrored the sex-allocation patterns of the resident population on their new reef. Transplants had significantly lower male allocation than representatives from their source population, largely as a result of reduced testis mass relative to body size.

Is there an own-race preference in attractiveness?

PubMed

Burke, Darren; Nolan, Caroline; Hayward, William Gordon; Russell, Robert; Sulikowski, Danielle

2013-08-15

Even in multicultural nations interracial relationships and marriages are quite rare, one reflection of assortative mating. A relatively unexplored factor that could explain part of this effect is that people may find members of their own racial group more attractive than members of other groups. We tested whether there is an own-race preference in attractiveness judgments, and also examined the effect of familiarity by comparing the attractiveness ratings given by participants of different ancestral and geographic origins to faces of European, East Asian and African origin. We did not find a strong own-race bias in attractiveness judgments, but neither were the data consistent with familiarity, suggesting an important role for other factors determining the patterns of assortative mating observed.

Mating Behaviour in Laevicaudatan Clam Shrimp (Crustacea, Branchiopoda) and Functional Morphology of Male Claspers in a Phylogenetic Context: A Video-Based Analysis

PubMed Central

Sigvardt, Zandra M. S.; Olesen, Jørgen

2014-01-01

Clam shrimps are freshwater branchiopod crustaceans which often present complicated breeding systems including asexual reproduction (parthenogenesis) and mixed mating systems (in androdioecious species both selfing and outcrossing occurs due to the co-presence of hermaphrodites and males). Reproductive patterns of Spinicaudata, which contains most clam shrimp species, have received much attention. Another group of clam shrimps, Laevicaudata, which holds a key position in branchiopod phylogeny, has practically not been studied. As a part of the mating process, males clasp to the carapace margin of the females with a pair (or two pairs) of anterior trunk limbs modified as claspers. Previous studies have shown that clasper morphology is important in a phylogenetic context, and that some parts of the claspers in Spinicaudata and Laevicaudata may have undergone a remarkable parallel evolution. Here we have used video microscopy to study aspects of the mating behaviour, egg extrusion, and fertilization in Lynceus brachyurus (Laevicaudata). It is shown that fertilization is likely to be external and that the peculiar tri-lobed lateral lamellae of female's hind body assist in guiding the egg mass to the exopodal egg carriers where they are collected by their distal setation. The functional morphology of the male claspers was studied in detail by close-up video recordings. The movable “finger” of the clasper bends around the female's carapace edge and serves to hold the female during mating. The larger palp grasps around the female carapace margin in a way very similar to the movable “finger”, possibly indirectly providing sensory input on the “finger” position. A brief comparative study of the claspers of a spinicaudatan clam shrimp showed both similarities and differences to the laevicaudatan claspers. The presence of two pairs of claspers in Spinicaudata seems to give males a better hold of the female which may play a role during extended mate guarding. PMID:24392104

Mating behaviour in laevicaudatan clam shrimp (Crustacea, Branchiopoda) and functional morphology of male claspers in a phylogenetic context: a video-based analysis.

PubMed

Sigvardt, Zandra M S; Olesen, Jørgen

2014-01-01

Clam shrimps are freshwater branchiopod crustaceans which often present complicated breeding systems including asexual reproduction (parthenogenesis) and mixed mating systems (in androdioecious species both selfing and outcrossing occurs due to the co-presence of hermaphrodites and males). Reproductive patterns of Spinicaudata, which contains most clam shrimp species, have received much attention. Another group of clam shrimps, Laevicaudata, which holds a key position in branchiopod phylogeny, has practically not been studied. As a part of the mating process, males clasp to the carapace margin of the females with a pair (or two pairs) of anterior trunk limbs modified as claspers. Previous studies have shown that clasper morphology is important in a phylogenetic context, and that some parts of the claspers in Spinicaudata and Laevicaudata may have undergone a remarkable parallel evolution. Here we have used video microscopy to study aspects of the mating behaviour, egg extrusion, and fertilization in Lynceus brachyurus (Laevicaudata). It is shown that fertilization is likely to be external and that the peculiar tri-lobed lateral lamellae of female's hind body assist in guiding the egg mass to the exopodal egg carriers where they are collected by their distal setation. The functional morphology of the male claspers was studied in detail by close-up video recordings. The movable "finger" of the clasper bends around the female's carapace edge and serves to hold the female during mating. The larger palp grasps around the female carapace margin in a way very similar to the movable "finger", possibly indirectly providing sensory input on the "finger" position. A brief comparative study of the claspers of a spinicaudatan clam shrimp showed both similarities and differences to the laevicaudatan claspers. The presence of two pairs of claspers in Spinicaudata seems to give males a better hold of the female which may play a role during extended mate guarding.

Oxytocin reduces alcohol consumption in prairie voles.

PubMed

Stevenson, J R; Wenner, S M; Freestone, D M; Romaine, C C; Parian, M C; Christian, S M; Bohidar, A E; Ndem, J R; Vogel, I R; O'Kane, C M

2017-10-01

Alcohol use disorder (AUD) negatively affects millions of people every year in the United States, and effective treatments for AUD are still needed. The neuropeptide oxytocin has shown promise for reducing alcohol drinking in mice and rats. Because oxytocin also plays a key role in complex prosocial behaviors like bonding and attachment, we tested the effect of oxytocin on alcohol drinking in prairie voles, a species that both consumes high amounts of alcohol and forms oxytocin dependent social bonds in a manner similar to humans. Oxytocin treatment (1.0, 3.0, and 10.0mg/kg, i.p.) reduced alcohol consumption in male and female prairie voles in animals that had access to 15% ethanol vs water every other day for 12 alcohol drinking sessions. In animals with continuous access to 15% alcohol and water, oxytocin (3.0mg/kg) reduced alcohol consumption only in the first hour of access after treatment, with no significant effects on consumption over the 24-hr period. In an open field locomotor test, oxytocin (1.0, 3.0, and 10.0mg/kg, i.p.) did not affect overall locomotor activity; however, ethanol (2g/kg, i.p.) increased locomotor activity in males and females, and produced anxiolytic effects (increased time in the center of an open field) in females only. Because prairie voles have been shown to match the alcohol consumption of their cage mate, we evaluated the relationship between cage mates' alcohol drinking. There was an overall pattern of social facilitation (consumption by one cage mate predicted consumption by the other cage mate); however, we found significant individual differences across cages in which many cages did not show significant matching, and, in some cases one cage mate's consumption negatively predicted the other cage mate's consumption. Overall, our data provide support for the potential of oxytocin as a treatment to reduce alcohol consumption. Copyright © 2017 Elsevier Inc. All rights reserved.

Genome-Wide Identification, Characterization and Expression Analysis of the Solute Carrier 6 Gene Family in Silkworm (Bombyx mori)

PubMed Central

Tang, Xin; Liu, Huawei; Chen, Quanmei; Wang, Xin; Xiong, Ying; Zhao, Ping

2016-01-01

The solute carrier 6 (SLC6) gene family, initially known as the neurotransmitter transporters, plays vital roles in the regulation of neurotransmitter signaling, nutrient absorption and motor behavior. In this study, a total of 16 candidate genes were identified as SLC6 family gene homologs in the silkworm (Bombyx mori) genome. Spatio-temporal expression patterns of silkworm SLC6 gene transcripts indicated that these genes were highly and specifically expressed in midgut, brain and gonads; moreover, these genes were expressed primarily at the feeding stage or adult stage. Levels of expression for most midgut-specific and midgut-enriched gene transcripts were down-regulated after starvation but up-regulated after re-feeding. In addition, we observed that expression levels of these genes except for BmSLC6-15 and BmGT1 were markedly up-regulated by a juvenile hormone analog. Moreover, brain-enriched genes showed differential expression patterns during wandering and mating processes, suggesting that these genes may be involved in modulating wandering and mating behaviors. Our results improve our understanding of the expression patterns and potential physiological functions of the SLC6 gene family, and provide valuable information for the comprehensive functional analysis of the SLC6 gene family. PMID:27706106

Genome-Wide Identification, Characterization and Expression Analysis of the Solute Carrier 6 Gene Family in Silkworm (Bombyx mori).

PubMed

Tang, Xin; Liu, Huawei; Chen, Quanmei; Wang, Xin; Xiong, Ying; Zhao, Ping

2016-10-03

The solute carrier 6 (SLC6) gene family, initially known as the neurotransmitter transporters, plays vital roles in the regulation of neurotransmitter signaling, nutrient absorption and motor behavior. In this study, a total of 16 candidate genes were identified as SLC6 family gene homologs in the silkworm (Bombyx mori) genome. Spatio-temporal expression patterns of silkworm SLC6 gene transcripts indicated that these genes were highly and specifically expressed in midgut, brain and gonads; moreover, these genes were expressed primarily at the feeding stage or adult stage. Levels of expression for most midgut-specific and midgut-enriched gene transcripts were down-regulated after starvation but up-regulated after re-feeding. In addition, we observed that expression levels of these genes except for BmSLC6-15 and BmGT1 were markedly up-regulated by a juvenile hormone analog. Moreover, brain-enriched genes showed differential expression patterns during wandering and mating processes, suggesting that these genes may be involved in modulating wandering and mating behaviors. Our results improve our understanding of the expression patterns and potential physiological functions of the SLC6 gene family, and provide valuable information for the comprehensive functional analysis of the SLC6 gene family.

Divergence in genital morphology may contribute to mechanical reproductive isolation in a millipede

PubMed Central

Wojcieszek, Janine M; Simmons, Leigh W

2013-01-01

Genitalia appear to evolve rapidly and divergently in taxa with internal fertilization. The current consensus is that intense directional sexual selection drives the rapid evolution of genitalia. Recent research on the millipede Antichiropus variabilis suggests that the male genitalia are currently experiencing stabilizing selection – a pattern of selection expected for lock-and-key structures that enforce mate recognition and reproductive isolation. Here, we investigate how divergence in genital morphology affects reproductive compatibility among isolated populations of A. variabilis. Females from a focal population were mated first to a male from their own population and, second, to a male from one of two populations with divergent genital morphology. We observed variation in mating behavior that might indicate the emergence of precopulatory reproductive barriers: males from one divergent population took significantly longer to recognize females and exhibited mechanical difficulty in genital insertion. Moreover, we observed very low paternity success for extra-population males who were successful in copulating. Our data suggest that divergence in genital shape may be contributing to reproductive isolation, and incipient speciation among isolated populations of A. variabilis. PMID:23467632

Masculine men articulate less clearly.

PubMed

Kempe, Vera; Puts, David A; Cárdenas, Rodrigo A

2013-12-01

In previous research, acoustic characteristics of the male voice have been shown to signal various aspects of mate quality and threat potential. But the human voice is also a medium of linguistic communication. The present study explores whether physical and vocal indicators of male mate quality and threat potential are linked to effective communicative behaviors such as vowel differentiation and use of more salient phonetic variants of consonants. We show that physical and vocal indicators of male threat potential, height and formant position, are negatively linked to vowel space size, and that height and levels of circulating testosterone are negatively linked to the use of the aspirated variant of the alveolar stop consonant /t/. Thus, taller, more masculine men display less clarity in their speech and prefer phonetic variants that may be associated with masculine attributes such as toughness. These findings suggest that vocal signals of men's mate quality and/or dominance are not confined to the realm of voice acoustics but extend to other aspects of communicative behavior, even if this means a trade-off with speech patterns that are considered communicatively advantageous, such as clarity and indexical cues to higher social class.

The contrasting role of male relatedness in different mechanisms of sexual selection in red junglefowl.

PubMed

Tan, Cedric Kai Wei; Doyle, Philippa; Bagshaw, Emma; Richardson, David S; Wigby, Stuart; Pizzari, Tommaso

2017-02-01

In structured populations, competition for reproductive opportunities should be relaxed among related males. The few tests of this prediction often neglect the fact that sexual selection acts through multiple mechanisms, both before and after mating. We performed experiments to study the role of within-group male relatedness across pre- and postcopulatory mechanisms of sexual selection in social groups of red junglefowl, Gallus gallus, in which two related males and one unrelated male competed over females unrelated to all the males. We confirm theoretical expectations that, after controlling for male social status, competition over mating was reduced among related males. However, this effect was contrasted by other sexual selection mechanisms. First, females biased male mating in favor of the unrelated male, and might also favor his inseminations after mating. Second, males invested more-rather than fewer-sperm in postcopulatory competition with relatives. A number of factors may contribute to explain this counterintuitive pattern of sperm allocation, including trade-offs between male investment in pre- versus postcopulatory competition, differences in the relative relatedness of pre- versus postcopulatory competitors, and female bias in sperm utilization in response to male relatedness. Collectively, these results reveal that within-group male relatedness may have contrasting effects in different mechanisms of sexual selection. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Ecological segregation in a small mammal hybrid zone: habitat-specific mating opportunities and selection against hybrids restrict gene flow on a fine spatial scale.

PubMed

Shurtliff, Quinn R; Murphy, Peter J; Matocq, Marjorie D

2014-03-01

The degree to which closely related species interbreed is determined by a complex interaction of ecological, behavioral, and genetic factors. We examine the degree of interbreeding between two woodrat species, Neotoma bryanti and N. lepida, at a sharp ecological transition. We identify the ecological association of each genotypic class, assess the opportunity for mating between these groups, and test whether they have similar patterns of year-to-year persistence on our study site. We find that 13% of individuals have a hybrid signature but that the two parental populations and backcrosses are highly segregated by habitat type and use. Also, we find that adult hybrids are comparable to parental types in terms of year-to-year persistence on our site but that, among juveniles, significantly fewer hybrids reach adulthood on site compared to their purebred counterparts. Our analyses show that this hybrid zone is maintained by occasional nonassortative mating coupled with hybrid fertility, but that these factors are balanced by lower apparent survival of juvenile hybrids and habitat-based preference or selection that limits heterospecific mating while promoting backcrossing to habitat-specific genotypes. This system presents a novel example of the role that sharp resource gradients play in reproductive isolation and the potential for genetic introgression. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Adaptations to sexual selection and sexual conflict: insights from experimental evolution and artificial selection.

PubMed

Edward, Dominic A; Fricke, Claudia; Chapman, Tracey

2010-08-27

Artificial selection and experimental evolution document natural selection under controlled conditions. Collectively, these techniques are continuing to provide fresh and important insights into the genetic basis of evolutionary change, and are now being employed to investigate mating behaviour. Here, we focus on how selection techniques can reveal the genetic basis of post-mating adaptations to sexual selection and sexual conflict. Alteration of the operational sex ratio of adult Drosophila over just a few tens of generations can lead to altered ejaculate allocation patterns and the evolution of resistance in females to the costly effects of elevated mating rates. We provide new data to show how male responses to the presence of rivals can evolve. For several traits, the way in which males responded to rivals was opposite in lines selected for male-biased, as opposed to female-biased, adult sex ratio. This shows that the manipulation of the relative intensity of intra- and inter-sexual selection can lead to replicable and repeatable effects on mating systems, and reveals the potential for significant contemporary evolutionary change. Such studies, with important safeguards, have potential utility for understanding sexual selection and sexual conflict across many taxa. We discuss how artificial selection studies combined with genomics will continue to deepen our knowledge of the evolutionary principles first laid down by Darwin 150 years ago.

Mating Signals Indicating Sexual Receptiveness Induce Unique Spatio-Temporal EEG Theta Patterns in an Anuran Species

PubMed Central

Fang, Guangzhan; Yang, Ping; Cui, Jianguo; Yao, Dezhong; Brauth, Steven E.; Tang, Yezhong

2012-01-01

Female mate choice is of importance for individual fitness as well as a determining factor in genetic diversity and speciation. Nevertheless relatively little is known about how females process information acquired from males during mate selection. In the Emei music frog, Babina daunchina, males normally call from hidden burrows and females in the reproductive stage prefer male calls produced from inside burrows compared with ones from outside burrows. The present study evaluated changes in electroencephalogram (EEG) power output in four frequency bands induced by male courtship vocalizations on both sides of the telencephalon and mesencephalon in females. The results show that (1) both the values of left hemispheric theta relative power and global lateralization in the theta band are modulated by the sexual attractiveness of the acoustic stimulus in the reproductive stage, suggesting the theta oscillation is closely correlated with processing information associated with mate choice; (2) mean relative power in the beta band is significantly greater in the mesencephalon than the left telencephalon, regardless of reproductive status or the biological significance of signals, indicating it is associated with processing acoustic features and (3) relative power in the delta and alpha bands are not affected by reproductive status or acoustic stimuli. The results imply that EEG power in the theta and beta bands reflect different information processing mechanisms related to vocal recognition and auditory perception in anurans. PMID:23285010

Increased frequency of self-fertile isolates in Phytophthora infestans may attribute to their higher fitness relative to the A1 isolates

PubMed Central

Zhu, Wen; Shen, Lin-Lin; Fang, Zhi-Guo; Yang, Li-Na; Zhang, Jia-Feng; Sun, Dan-Li; Zhan, Jiasui

2016-01-01

Knowledge of population dynamics of mating types is important for better understanding pathogen’s evolutionary potential and sustainable management of natural and chemical resources such as host resistances and fungicides. In this study, 2250 Phytophthora infestans isolates sampled from 61 fields across China were assayed for spatiotemporal dynamics of mating type frequency. Self-fertile isolates dominated in ~50% of populations and all but one cropping region with an average frequency of 0.64 while no A2 isolates were detected. Analyses of 140 genotypes consisting of 82 self-fertile and 58 A1 isolates indicated that on average self-fertile isolates grew faster, demonstrated higher aggressiveness and were more tolerant to fungicides than A1 isolates; Furthermore, pattern of association between virulence complexity (defined as the number of differential cultivars on which an isolate can induce disease) and frequency was different in the two mating types. In A1 isolates, virulence complexity was negatively correlated (r = −0.515, p = 0.043) with frequency but this correlation was positive (r = 0.532, p = 0.037) in self-fertile isolates. Our results indicate a quick increase of self-fertile isolates possibly attributable to their higher fitness relative to A1 mating type counterpart in the field populations of P. infestans in China. PMID:27384813

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.

Mating and male pheromone kill Caenorhabditis males through distinct mechanisms.

PubMed

Shi, Cheng; Runnels, Alexi M; Murphy, Coleen T

2017-03-14

Differences in longevity between sexes is a mysterious yet general phenomenon across great evolutionary distances. To test the roles of responses to environmental cues and sexual behaviors in longevity regulation, we examined Caenorhabditis male lifespan under solitary, grouped, and mated conditions. We find that neurons and the germline are required for male pheromone-dependent male death. Hermaphrodites with a masculinized nervous system secrete male pheromone and are susceptible to male pheromone killing. Male pheromone-mediated killing is unique to androdioecious Caenorhabditis , and may reduce the number of males in hermaphroditic populations; neither males nor females of gonochoristic species are susceptible to male pheromone killing. By contrast, mating-induced death, which is characterized by germline-dependent shrinking, glycogen loss, and ectopic vitellogenin expression, utilizes distinct molecular pathways and is shared between the sexes and across species. The study of sex- and species-specific regulation of aging reveals deeply conserved mechanisms of longevity and population structure regulation.

Glass Effect in Inbreeding-Avoidance Systems: Minimum Viable Population for Outbreeders

NASA Astrophysics Data System (ADS)

Tainaka, Kei-ichi; Itoh, Yoshiaki

1996-10-01

Many animals, birds and plants have evolved mechanisms to avoid inbreeding between close relatives.Such mating systems may have developed several methods for restricting mate choice.If fragmentation of habitats becomes serious, these methods may lead to a lack of acceptable mates. We call this “glass effect”which is a generalization of the so-called Allee effect.We present two inbreeding-avoidance (outbreeding) models.Both models show that outbreeders have a high risk infragmented environments.We thus obtain the minimum viable population (MVP). It is found that the value of MVP amounts to the range from several hundred to several thousand individuals.While this value is much larger than thoseobtained by the previous demographic theories,it is consistent with recent empirical estimations.Moreover, we find that the glass effect is caused bydynamically induced clusters of relatives.This suggests that genetic variation will be decreased by the outbreeding in a highly fragmented environment.

Body Weight and Matching with a Physically Attractive Romantic Partner

ERIC Educational Resources Information Center

Carmalt, Julie H.; Cawley, John; Joyner, Kara; Sobal, Jeffery

2008-01-01

Matching and attribute trade are two perspectives used to explain mate selection. We investigated patterns of matching and trade, focusing on obesity, using Add Health Romantic Pair data (N = 1,405 couples). Obese individuals, relative to healthy weight individuals, were less likely to have physically attractive partners, with this disadvantage…

Spectrally tuned structural and pigmentary coloration of birdwing butterfly wing scales.

PubMed

Wilts, Bodo D; Matsushita, Atsuko; Arikawa, Kentaro; Stavenga, Doekele G

2015-10-06

The colourful wing patterns of butterflies play an important role for enhancing fitness; for instance, by providing camouflage, for interspecific mate recognition, or for aposematic display. Closely related butterfly species can have dramatically different wing patterns. The phenomenon is assumed to be caused by ecological processes with changing conditions, e.g. in the environment, and also by sexual selection. Here, we investigate the birdwing butterflies, Ornithoptera, the largest butterflies of the world, together forming a small genus in the butterfly family Papilionidae. The wings of these butterflies are marked by strongly coloured patches. The colours are caused by specially structured wing scales, which act as a chirped multilayer reflector, but the scales also contain papiliochrome pigments, which act as a spectral filter. The combined structural and pigmentary effects tune the coloration of the wing scales. The tuned colours are presumably important for mate recognition and signalling. By applying electron microscopy, (micro-)spectrophotometry and scatterometry we found that the various mechanisms of scale coloration of the different birdwing species strongly correlate with the taxonomical distribution of Ornithoptera species. © 2015 The Author(s).

Spectrally tuned structural and pigmentary coloration of birdwing butterfly wing scales

PubMed Central

Wilts, Bodo D.; Matsushita, Atsuko; Arikawa, Kentaro; Stavenga, Doekele G.

2015-01-01

The colourful wing patterns of butterflies play an important role for enhancing fitness; for instance, by providing camouflage, for interspecific mate recognition, or for aposematic display. Closely related butterfly species can have dramatically different wing patterns. The phenomenon is assumed to be caused by ecological processes with changing conditions, e.g. in the environment, and also by sexual selection. Here, we investigate the birdwing butterflies, Ornithoptera, the largest butterflies of the world, together forming a small genus in the butterfly family Papilionidae. The wings of these butterflies are marked by strongly coloured patches. The colours are caused by specially structured wing scales, which act as a chirped multilayer reflector, but the scales also contain papiliochrome pigments, which act as a spectral filter. The combined structural and pigmentary effects tune the coloration of the wing scales. The tuned colours are presumably important for mate recognition and signalling. By applying electron microscopy, (micro-)spectrophotometry and scatterometry we found that the various mechanisms of scale coloration of the different birdwing species strongly correlate with the taxonomical distribution of Ornithoptera species. PMID:26446560

Home range and territoriality of two Hawaiian honeycreepers, the 'Akohekohe and Maui Parrotbill

USGS Publications Warehouse

Pratt, Thane K.; Simon, John C.; Farm, Brian P.; Berlin, Kim E.; Kowalsky, James R.

2001-01-01

Hawaiian honeycreepers have radiated into a diversity of trophic niches and patterns of space-use. We investigated space-use in two honeycreeper species, the ‘Ākohekohe (Palmeria dolei), an endangered nectarivore, and Maui Parrotbill (Pseudonestor xanthophrys), an endangered wood excavator, by mapping the home ranges and dispersion of color-banded individuals at a study site in relatively undisturbed montane cloud forest on Maui Island, Hawai‘i. With 20% of outlying points excluded, home-range size averaged much smaller for adult male ‘Ākohekohe (0.56 ha) than for male Maui Parrotbill (2.26 ha). In both species, a female's home range mostly overlapped that of her mate. Adult male Maui Parrotbill defended year-round home ranges from which they excluded conspecifics except for their mates and dependent offspring. Although our data suggest that ‘Ākohekohe also maintained all-purpose territories, the evidence is less convincing because these birds were seen feeding in the home ranges of other individuals. By defending all-purpose territories, these two species depart from the more common honeycreeper pattern of sharing large, undefended home ranges.

Counter-perfume: using pheromones to prevent female remating.

PubMed

Malouines, Clara

2017-08-01

Strong selection to secure paternity in polyandrous species leads to the evolution of numerous chemicals in the male's seminal content. These include antiaphrodisiac pheromones, which are transmitted from the male to the female during mating to render her unattractive to subsequent males. An increasing number of species have been shown to use these chemicals. Herein, I examine the taxonomic distribution of species using antiaphrodisiac pheromones, the selection pressures driving their evolution in both males and females, and the ecological interactions in which these pheromones are involved. The literature review shows a highly skewed distribution of antiaphrodisiac use; all species currently known to use them are insects with the exception of the garter snakes Thamnophis sirtalis parietalis and T. radix. Nonetheless, many taxa have not yet been tested for the presence of antiaphrodisiacs, in groups both closely and distantly related to species known to express them. Within the Insecta, there have been multiple cases of convergent evolution of antiaphrodisiac pheromones using different chemical compounds and methods of transmission. Antiaphrodisiacs usually benefit males, but their effect on females is variable as they can either prevent them from mating multiple times or help them reduce male harassment when they are unreceptive. Some indirect costs of antiaphrodisiacs also impact both males and females, but more research is needed to determine how general this pattern is. Additional research is also important to understand how antiaphrodisiacs interact with the reproductive biology and sexual communication in different species. © 2016 Cambridge Philosophical Society.

Utilization of pheromones in the population management of moth pests.

PubMed Central

Cardé, R T

1976-01-01

Pheromones are substances emitted by one individual of a species and eliciting a specific response in a second individual of the same species. In moths (Lepidoptera) generally females lure males for mating by emission of a sex attractant pheromone comprised of either one or more components. Since 1966 the identification of the pheromone blends of many moth pests has allowed investigations into the use of these messengers for population manipulation. Pheromone-baited traps may be used both to detect pest presence and to estimate population density, so that conventional control tactics can be employed only as required and timed precisely for maximum effectiveness. Attractant traps also can be utilized for direct population suppression when the traps are deployed at a density effective in reducing mating success sufficiently to achieve control. A third use pattern of pheromones and related compounds is disruption of pheromone communication via atmospheric permeation with synthetic disruptants. The behavioral modifications involved in disruption of communication may include habituation of the normal response sequence (alteration of the pheromone response threshold) and "confusion" (inability of the organism to perceive and orient to the naturally emitted lure). Disruption of communication employing the natural pheromone components as the disruptant has been most successful, although nonattractant behavioral modifiers structurally similar to the pheromone components also may prove useful. Possible future resistance to direct pheromone manipulation may be expected to involve the evolution of behavioral and sensory changes that minimize the informational overlap between the natural pheromone system and the pheromone control technique. PMID:789060

Ascent heat transfer rate distribution on the North American Rockwell delta wing orbiter and the General Dynamics/Convair booster at a Mach number of 8 (mated)

NASA Technical Reports Server (NTRS)

Matthews, R. K.; Martindale, W. R.; Warmbrod, J. D.

1972-01-01

A wind tunnel test program to determine aerodynamic interference heating on the North American Rockwell orbiter mated with the General Dynamics Convair booster is discussed. The tests were conducted at the Arnold Engineering Development Center (AEDC) in Tunnel B of the von Karman Gas Dynamics Facility (VKF). The test period was June 1971. Heat-transfer rates were determined by the phase-change paint technique on 0.013-scale Stycast models using Tempilaq as the surface temperature indicator. The nominal test conditions were: Mach 8, free-stream unit length Reynolds numbers of 1.25 x one million and 2.55 x one million angles of attack of -5, 0, +5 deg. Model details, test conditions, phase-change paint photographs and reduced heat-transfer coefficients are presented.

Reconstructing the regulatory circuit of cell fate determination in yeast mating response.

PubMed

Shao, Bin; Yuan, Haiyu; Zhang, Rongfei; Wang, Xuan; Zhang, Shuwen; Ouyang, Qi; Hao, Nan; Luo, Chunxiong

2017-07-01

Massive technological advances enabled high-throughput measurements of proteomic changes in biological processes. However, retrieving biological insights from large-scale protein dynamics data remains a challenging task. Here we used the mating differentiation in yeast Saccharomyces cerevisiae as a model and developed integrated experimental and computational approaches to analyze the proteomic dynamics during the process of cell fate determination. When exposed to a high dose of mating pheromone, the yeast cell undergoes growth arrest and forms a shmoo-like morphology; however, at intermediate doses, chemotropic elongated growth is initialized. To understand the gene regulatory networks that control this differentiation switch, we employed a high-throughput microfluidic imaging system that allows real-time and simultaneous measurements of cell growth and protein expression. Using kinetic modeling of protein dynamics, we classified the stimulus-dependent changes in protein abundance into two sources: global changes due to physiological alterations and gene-specific changes. A quantitative framework was proposed to decouple gene-specific regulatory modes from the growth-dependent global modulation of protein abundance. Based on the temporal patterns of gene-specific regulation, we established the network architectures underlying distinct cell fates using a reverse engineering method and uncovered the dose-dependent rewiring of gene regulatory network during mating differentiation. Furthermore, our results suggested a potential crosstalk between the pheromone response pathway and the target of rapamycin (TOR)-regulated ribosomal biogenesis pathway, which might underlie a cell differentiation switch in yeast mating response. In summary, our modeling approach addresses the distinct impacts of the global and gene-specific regulation on the control of protein dynamics and provides new insights into the mechanisms of cell fate determination. We anticipate that our integrated experimental and modeling strategies could be widely applicable to other biological systems.

Asymmetric Hybridization in Cattails (Typha spp.) and Its Implications for the Evolutionary Maintenance of Native Typha latifolia.

PubMed

Pieper, Sara J; Nicholls, Allison A; Freeland, Joanna R; Dorken, Marcel E

2017-07-01

Cattails (Typha spp.) have become an increasingly dominant component of wetlands in eastern North America and this dominance is largely attributable to the high frequency of Typha × glauca, the hybrid of native Typha latifolia and putatively introduced Typha angustifolia. Hybridization in this group is asymmetric, with T. angustifolia nearly always the maternal parent of F1 hybrids. However, the magnitude of hybrid infertility and whether mating asymmetries extend to the formation of advanced-generation hybrids have not been examined. We used hand-crosses to measure seed set and germination success. We found that mating asymmetries extend to the formation of back-crosses, with ~0 seeds set when T. latifolia was pollinated by hybrid cattails. Seed set was unaffected by pollen source for T. × glauca or T. angustifolia. However, seed production by T. angustifolia was consistently high while that of T. × glauca was variable and when pollinated by other T. × glauca more than 75% lower than for any other intraspecific cross indicating reduced hybrid fertility. We used these results to parameterize a model of hybrid zone evolution in which mating patterns and fertility were governed by interactions between alleles at nuclear and cytoplasmic loci. The model revealed that asymmetric mating and reduced hybrid fertility should favor the maintenance of T. latifolia over T. angustifolia compared to null expectations. However, the model also indicated restrictive conditions for the long-term maintenance of T. latifolia within populations, indicating that asymmetric mating might only stall rather than prevent the displacement of native cattails by hybrids. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Transitions in Sexuality: Recapitulation of an Ancestral Tri- and Tetrapolar Mating System in Cryptococcus neoformans▿ †

PubMed Central

Hsueh, Yen-Ping; Fraser, James A.; Heitman, Joseph

2008-01-01

Sex is orchestrated by the mating-type locus (MAT) in fungi and by sex chromosomes in plants and animals. In fungi, two patterns of sexuality occur: bipolar with a single, typically biallelic sex determinant that promotes inbreeding, and tetrapolar with two unlinked, often multiallelic sex determinants that restrict inbreeding. Multiallelism in either bipolar or tetrapolar mating systems promotes outcrossing. Cryptococcus neoformans is a pathogenic bipolar yeast with two unusually large MAT alleles (a/α) spanning >100 kb, ∼100-fold larger than many other fungal MAT loci. Based on comparative genomic analysis, this unusual MAT locus is hypothesized to have evolved from an ancestral tetrapolar system. In this model, the unlinked homeodomain (HD) transcription factor and pheromone/receptor tetrapolar loci acquired additional sex-related genes and then fused via chromosomal translocation, forming an intermediate transitional mating system (which we term tripolar), which then underwent recombination and gene conversion to fashion the extant bipolar MAT alleles. To experimentally validate this model, C. neoformans was engineered to have a tetrapolar mating system by relocating the MAT SXI1α and SXI2a HD genes to an unlinked genomic locale. Genetic and molecular analyses revealed that this modified organism could complete a tetrapolar sexual cycle. Analysis of progeny generated from bipolar, tripolar, and tetrapolar crosses provides direct experimental evidence that the tripolar state confers decreased fertility and therefore may represent an unstable evolutionary intermediate. These findings illustrate how transitions between outcrossing and inbreeding preference occur by involving sex determinant linkage and collapse from multiallelic to biallelic sex determination, providing insights into both fungal sex evolution and early steps in sex chromosome evolution. PMID:18723606