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…

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

Overcoming statistical bias to estimate genetic mating systems in open populations: a comparison of Bateman's principles between the sexes in a sex-role-reversed pipefish.

PubMed

Mobley, Kenyon B; Jones, Adam G

2013-03-01

The genetic mating system is a key component of the sexual selection process, yet methods for the quantification of mating systems remain controversial. One approach involves metrics derived from Bateman's principles, which are based on variances in mating and reproductive success and the relationship between them. However, these measures are extremely difficult to measure for both sexes in open populations, because missing data can result in biased estimates. Here, we develop a novel approach for the estimation of mating system metrics based on Bateman's principles and apply it to a microsatellite-based parentage analysis of a natural population of the dusky pipefish, Syngnathus floridae. Our results show that both male and female dusky pipefish have significantly positive Bateman gradients. However, females exhibit larger values of the opportunity for sexual selection and the opportunity for selection compared to males. These differences translate into a maximum intensity of sexual selection (S'max) for females three times larger than that for males. Overall, this study identifies a critical source of bias that affects studies of mating systems in open populations, presents a novel method for overcoming this bias, and applies this method for the first time in a sex-role-reversed pipefish. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Feed-backs among inbreeding, inbreeding depression in sperm traits, and sperm competition can drive evolution of costly polyandry.

PubMed

Bocedi, Greta; Reid, Jane M

2017-12-01

Ongoing ambitions are to understand the evolution of costly polyandry and its consequences for species ecology and evolution. Emerging patterns could stem from feed-back dynamics between the evolving mating system and its genetic environment, defined by interactions among kin including inbreeding. However, such feed-backs are rarely considered in nonselfing systems. We use a genetically explicit model to demonstrate a mechanism by which inbreeding depression can select for polyandry to mitigate the negative consequences of mating with inbred males, rather than to avoid inbreeding, and to elucidate underlying feed-backs. Specifically, given inbreeding depression in sperm traits, costly polyandry evolved to ensure female fertility, without requiring explicit inbreeding avoidance. Resulting sperm competition caused evolution of sperm traits and further mitigated the negative effect of inbreeding depression on female fertility. The evolving mating system fed back to decrease population-wide homozygosity, and hence inbreeding. However, the net overall decrease was small due to compound effects on the variances in sex-specific reproductive success and paternity skew. Purging of deleterious mutations did not eliminate inbreeding depression in sperm traits or hence selection for polyandry. Overall, our model illustrates that polyandry evolution, both directly and through sperm competition, might facilitate evolutionary rescue for populations experiencing sudden increases in inbreeding. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

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.

Multiple convergent supergene evolution events in mating-type chromosomes.

PubMed

Branco, Sara; Carpentier, Fantin; Rodríguez de la Vega, Ricardo C; Badouin, Hélène; Snirc, Alodie; Le Prieur, Stéphanie; Coelho, Marco A; de Vienne, Damien M; Hartmann, Fanny E; Begerow, Dominik; Hood, Michael E; Giraud, Tatiana

2018-05-21

Convergent adaptation provides unique insights into the predictability of evolution and ultimately into processes of biological diversification. Supergenes (beneficial gene linkage) are striking examples of adaptation, but little is known about their prevalence or evolution. A recent study on anther-smut fungi documented supergene formation by rearrangements linking two key mating-type loci, controlling pre- and post-mating compatibility. Here further high-quality genome assemblies reveal four additional independent cases of chromosomal rearrangements leading to regions of suppressed recombination linking these mating-type loci in closely related species. Such convergent transitions in genomic architecture of mating-type determination indicate strong selection favoring linkage of mating-type loci into cosegregating supergenes. We find independent evolutionary strata (stepwise recombination suppression) in several species, with extensive rearrangements, gene losses, and transposable element accumulation. We thus show remarkable convergence in mating-type chromosome evolution, recurrent supergene formation, and repeated evolution of similar phenotypes through different genomic changes.

The Roles of Sexual and Viability Selection in the Evolution of Incomplete Reproductive Isolation: From Allopatry to Sympatry.

PubMed

Cotto, Olivier; Servedio, Maria R

2017-11-01

In recent years, theoretical models have introduced the concept that ongoing hybridization between "good" species can occur because incomplete reproductive isolation can be a selected optimum. They furthermore show that positive frequency-dependent sexual selection, which is naturally generated by some of the underlying processes that lead to assortative mating, plays a key role in the evolution of incomplete reproductive isolation. This occurs, however, through different mechanisms in sympatric versus allopatric scenarios. We investigate the evolution of incomplete reproductive isolation by sexual selection in scenarios ranging from sympatry to allopatry, to examine how these mechanisms interact. We consider an ecological scenario in which there are two habitats used during foraging and individuals can breed either within a habitat or in a common mating pool. We find that when trait divergence is maintained, sexual selection drives the evolution of choosiness in opposite ways in the common mating pool versus within each habitat. Specifically, strong choosiness is favored in the common mating pool, whereas intermediate choosiness is favored within habitat; the interaction of these forces determines whether intermediate reproductive isolation ultimately evolves in the system. We further find cases where the evolution of stronger choosiness occurs but leads to the loss of divergence. Overall, our study shows that contrasting forces on the evolution of reproductive isolation can occur in different mating areas, and we propose a new avenue for understanding the diversity in levels of reproductive isolation within and across species.

Mating system and the evolution of sex-specific mortality rates in two nymphalid butterflies.

PubMed

Wiklund, Christer; Gotthard, Karl; Nylin, Sören

2003-09-07

Life-history theory predicts that organisms should invest resources into intrinsic components of lifespan only to the degree that it pays off in terms of reproductive success. The benefit of a long life may differ between the sexes and different mating systems may therefore select for different sex-specific mortality rates. In insects with polyandrous mating systems, females mate throughout their lives and male reproductive success is likely to increase monotonously with lifespan. In monandrous systems, where the mating season is less protracted because receptive females are available only at the beginning of the flight season, male mating success should be less dependent on a long lifespan. Here, we show, in a laboratory experiment without predation, that the duration of the mating season is longer in the polyandrous comma butterfly, Polygonia c-album, than in the monandrous peacock butterfly, Inachis io, and that, in line with predictions, male lifespan is shorter than female lifespan in I. io, whereas male and female lifespans are similar in P. c-album.

Feed‐backs among inbreeding, inbreeding depression in sperm traits, and sperm competition can drive evolution of costly polyandry

PubMed Central

Bocedi, Greta; Reid, Jane M.

2017-01-01

Abstract Ongoing ambitions are to understand the evolution of costly polyandry and its consequences for species ecology and evolution. Emerging patterns could stem from feed‐back dynamics between the evolving mating system and its genetic environment, defined by interactions among kin including inbreeding. However, such feed‐backs are rarely considered in nonselfing systems. We use a genetically explicit model to demonstrate a mechanism by which inbreeding depression can select for polyandry to mitigate the negative consequences of mating with inbred males, rather than to avoid inbreeding, and to elucidate underlying feed‐backs. Specifically, given inbreeding depression in sperm traits, costly polyandry evolved to ensure female fertility, without requiring explicit inbreeding avoidance. Resulting sperm competition caused evolution of sperm traits and further mitigated the negative effect of inbreeding depression on female fertility. The evolving mating system fed back to decrease population‐wide homozygosity, and hence inbreeding. However, the net overall decrease was small due to compound effects on the variances in sex‐specific reproductive success and paternity skew. Purging of deleterious mutations did not eliminate inbreeding depression in sperm traits or hence selection for polyandry. Overall, our model illustrates that polyandry evolution, both directly and through sperm competition, might facilitate evolutionary rescue for populations experiencing sudden increases in inbreeding. PMID:28895138

Evolution of mating systems in coral reef gobies and constraints on mating system plasticity

NASA Astrophysics Data System (ADS)

Hernaman, V.; Munday, P. L.

2007-09-01

Social and mating systems can be influenced by the distribution, abundance, and economic defendability of breeding partners and essential resources. Polygyny is predicted where males can economically defend multiple females or essential resources used by females. In contrast, monogamy is predicted where neither sex can monopolise multiple partners, either directly or through resource control, but where one mate is economically defendable. The mating system and reproductive behaviour of five species of coral reef goby were investigated and contrasted with population density and individual mobility. The two most abundant species ( Asterropteryx semipunctatus and Istigobius goldmanni) were polygynous. In contrast, the less populous and more widely dispersed epibenthic species ( Amblygobius bynoensis, Amblygobius phalaena and Valenciennea muralis) were pair forming and monogamous. All five species had low mobility, mostly remaining within metres (3 epibenthic species) or centimetres (2 cryptobenthic species) of a permanent shelter site. Interspecific differences in the mating system may have been shaped by differences in population density and the ability of reproductive individuals to economically defend breeding partners/sites. However, in a test of mating system plasticity, males of the three monogamous species did not mate polygynously when given the opportunity to do so in experimental manipulations of density and sex ratio. Mate guarding and complex spawning characteristics, which have likely co-evolved with the monogamous mating system, could contribute to mating system inflexibility by making polygynous mating unprofitable for individuals of the pair forming species, even when presented with current-day ecological conditions that usually favour polygyny.

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.

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.

Origin and occurrence of sexual and mating systems in Crustacea: a progression towards communal living and eusociality.

PubMed

Subramoniam, T

2013-12-01

Crustaceans are known for their unrivalled diversity of sexual systems, as well as peculiar mating associations to achieve maximum mating success and fertilization accomplishment. Although sexes are separate in most species, various types of hermaphroditism characterize these predominantly aquatic arthropods. A low operational sex ratio between female and male, together with temporally limited receptivity of females towards males, imposes restrictions on the structuring of mating systems in crustaceans. The basic mating systems consist of monogamy, polygamy, mate guarding and pure searching. Understandably, ecological influences may also play a determinative role in the evolution of such sexual and mating systems in crustaceans. An important outcome of the crustacean sexual biology is the development of complex social structures in many aquatic species, in much the same way insects have established them in terrestrial conditions. In addition, groups like isopods and certain families of brachyuran crabs have shown terrestrial adaptation, exhibiting peculiar reproductive modes, sometimes reminiscent of their terrestrial counterparts, insects. Many caridean shrimps, living in symbiotic relationship with other marine invertebrates in the coral reef habitats, have reached pinnacle of complexity in sexuality and peculiar mating behaviours, resulting in communal living and establishing advanced social systems, such as eusociality.

Evolution of the Bipolar Mating System of the Mushroom Coprinellus disseminatus From Its Tetrapolar Ancestors Involves Loss of Mating-Type-Specific Pheromone Receptor Function

PubMed Central

James, Timothy Y.; Srivilai, Prayook; Kües, Ursula; Vilgalys, Rytas

2006-01-01

Mating incompatibility in mushroom fungi is controlled by the mating-type loci. In tetrapolar species, two unlinked mating-type loci exist (A and B), whereas in bipolar species there is only one locus. The A and B mating-type loci encode homeodomain transcription factors and pheromones and pheromone receptors, respectively. Most mushroom species have a tetrapolar mating system, but numerous transitions to bipolar mating systems have occurred. Here we determined the genes controlling mating type in the bipolar mushroom Coprinellus disseminatus. Through positional cloning and degenerate PCR, we sequenced both the transcription factor and pheromone receptor mating-type gene homologs from C. disseminatus. Only the transcription factor genes segregate with mating type, discounting the hypothesis of genetic linkage between the A and B mating-type loci as the causal origin of bipolar mating behavior. The mating-type locus of C. disseminatus is similar to the A mating-type locus of the model species Coprinopsis cinerea and encodes two tightly linked pairs of homeodomain transcription factor genes. When transformed into C. cinerea, the C. disseminatus A and B homologs elicited sexual reactions like native mating-type genes. Although mating type in C. disseminatus is controlled by only the transcription factor genes, cellular functions appear to be conserved for both groups of genes. PMID:16461425

The Evolution of Mutual Mate Choice under Direct Benefits.

PubMed

Courtiol, Alexandre; Etienne, Loïc; Feron, Romain; Godelle, Bernard; Rousset, François

2016-11-01

In nature, the intensity of mate choice (i.e., choosiness) is highly variable within and between sexes. Despite growing empirical evidence of male and/or mutual mate choice, theoretical investigations of the joint evolution of female and male choosiness are few. In addition, previous approaches have often assumed an absence of trade-off between the direct benefits per mating and the lower mating rate that results from being choosy. Here we model the joint evolution of female and male choosiness when it is solely ruled by this fundamental trade-off. We show that this trade-off can generate a diversity of stable combinations of choosiness. Mutual mate choice can evolve only if both females and males exhibit long latency after mating. Furthermore, we show that an increase in choosiness in one sex does not necessarily prevent the evolution of mutual mate choice; the outcome depends on details shaping the trade-off: the life history, the decision rule for mate choice, and how the fecundity of a pair is shaped by the quality of both individuals. Last, we discuss the power of the sensitivity of the relative searching time (i.e., of the proportion of a lifetime spent searching for mates) as a predictor of the joint evolution of choosiness.

Can preference for oviposition sites initiate reproductive isolation in Callosobruchus maculatus?

PubMed

Rova, Emma; Björklund, Mats

2011-01-31

Theory has identified a variety of evolutionary processes that may lead to speciation. Our study includes selection experiments using different host plants and test key predictions concerning models of speciation based on host plant choice, such as the evolution of host use (preference and performance) and assortative mating. This study shows that after only ten generations of selection on different resources/hosts in allopatry, strains of the seed beetle Callosobruchus maculatus develop new resource preferences and show resource-dependent assortative mating when given the possibility to choose mates and resources during secondary contact. The resulting reduced gene flow between the different strains remained for two generations after contact before being overrun by disassortative mating. We show that reduced gene flow can evolve in a population due to a link between host preference and assortative mating, although this result was not found in all lines. However, consistent with models of speciation, assortative mating alone is not sufficient to maintain reproductive isolation when individuals disperse freely between hosts. We conclude that the evolution of reproductive isolation in this system cannot proceed without selection against hybrids. Other possible factors facilitating the evolution of isolation would be longer periods of allopatry, the build up of local adaptation or reduced migration upon secondary contact.

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.

Comparative analyses of the influence of developmental mode on phenotypic diversification rates in shorebirds

PubMed Central

Thomas, Gavin H; Freckleton, Robert P; Székely, Tamás

2006-01-01

Phenotypic diversity is not evenly distributed across lineages. Here, we describe and apply a maximum-likelihood phylogenetic comparative method to test for different rates of phenotypic evolution between groups of the avian order Charadriiformes (shorebirds, gulls and alcids) to test the influence of a binary trait (offspring demand; semi-precocial or precocial) on rates of evolution of parental care, mating systems and secondary sexual traits. In semi-precocial species, chicks are reliant on the parents for feeding, but in precocial species the chicks feed themselves. Thus, where the parents are emancipated from feeding the young, we predict that there is an increased potential for brood desertion, and consequently for the divergence of mating systems. In addition, secondary sexual traits are predicted to evolve faster in groups with less demanding young. We found that precocial development not only allows rapid divergence of parental care and mating behaviours, but also promotes the rapid diversification of secondary sexual characters, most notably sexual size dimorphism (SSD) in body mass. Thus, less demanding offspring appear to facilitate rapid evolution of breeding systems and some sexually selected traits. PMID:16769632

Comparative analyses of the influence of developmental mode on phenotypic diversification rates in shorebirds.

PubMed

Thomas, Gavin H; Freckleton, Robert P; Székely, Tamás

2006-07-07

Phenotypic diversity is not evenly distributed across lineages. Here, we describe and apply a maximum-likelihood phylogenetic comparative method to test for different rates of phenotypic evolution between groups of the avian order Charadriiformes (shorebirds, gulls and alcids) to test the influence of a binary trait (offspring demand; semi-precocial or precocial) on rates of evolution of parental care, mating systems and secondary sexual traits. In semi-precocial species, chicks are reliant on the parents for feeding, but in precocial species the chicks feed themselves. Thus, where the parents are emancipated from feeding the young, we predict that there is an increased potential for brood desertion, and consequently for the divergence of mating systems. In addition, secondary sexual traits are predicted to evolve faster in groups with less demanding young. We found that precocial development not only allows rapid divergence of parental care and mating behaviours, but also promotes the rapid diversification of secondary sexual characters, most notably sexual size dimorphism (SSD) in body mass. Thus, less demanding offspring appear to facilitate rapid evolution of breeding systems and some sexually selected traits.

Through evolution's eyes: extracting mate preferences by linking visual attention to adaptive design.

PubMed

Krupp, Daniel Brian

2008-02-01

Information is crucial to decision-making, including mate choice decisions. Perceptual systems, such as attention, evolved in part to forage for reproductive information; consequently, these systems can be used to reveal mate preferences. Here, I consider the place of visual information in human mate choice and provide a rationale for pressing into service methods drawn from the attention literature for the study of mate choice decisions. Because visual attention is allocated automatically and selectively, it may be used to complement common methods of mate preference assessment, such as self-report questionnaires and measures of genital arousal, while avoiding some of the pitfalls of these methods. Beyond the utility of increasing confidence in extant research findings by employing relatively unobtrusive methods, visual attention paradigms can also allow researchers to explore a variety of questions that are rarely asked, such as those concerned with signal efficiency and tradeoffs in the assessment of mate value.

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

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

Mating system and the evolution of sex-specific mortality rates in two nymphalid butterflies.

PubMed Central

Wiklund, Christer; Gotthard, Karl; Nylin, Sören

2003-01-01

Life-history theory predicts that organisms should invest resources into intrinsic components of lifespan only to the degree that it pays off in terms of reproductive success. The benefit of a long life may differ between the sexes and different mating systems may therefore select for different sex-specific mortality rates. In insects with polyandrous mating systems, females mate throughout their lives and male reproductive success is likely to increase monotonously with lifespan. In monandrous systems, where the mating season is less protracted because receptive females are available only at the beginning of the flight season, male mating success should be less dependent on a long lifespan. Here, we show, in a laboratory experiment without predation, that the duration of the mating season is longer in the polyandrous comma butterfly, Polygonia c-album, than in the monandrous peacock butterfly, Inachis io, and that, in line with predictions, male lifespan is shorter than female lifespan in I. io, whereas male and female lifespans are similar in P. c-album. PMID:12964985

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.

Conflict and cooperation over sex: the consequences of social and genetic polyandry for reproductive success in dunnocks.

PubMed

Santos, Eduardo S A; Santos, Luana L S; Lagisz, Malgorzata; Nakagawa, Shinichi

2015-11-01

Conflict and cooperation within and between the sexes are among the driving forces that lead to the evolution of mating systems. Among mating strategies, female genetic polyandry and male reproductive cooperation pose challenging evolutionary questions regarding the maintenance of systems where one sex suffers from reduced fitness. Here, we investigate the consequences of social and genetic polyandry for reproductive success of females and males in a population of the dunnock, Prunella modularis. We show that female multiple mating ameliorates the negative effects of inbreeding. We, however, found little evidence that females engage in extra-group (pair) mating with less related or more heterozygous males. Breeding in socially polyandrous groups reduced the amount of paternity lost to extra-group males, such that, on average, cobreeding and monogamous males fledged a similar number of young. Importantly, c. 30% of cobreeding male dyads were related, suggesting they could gain indirect fitness benefits. Taken together, cobreeding males achieve equivalent reproductive success to monogamous counterparts under most circumstances. Our study has revealed unexpected complexities in the variable mating system of dunnocks in New Zealand. Our results differ from the well-known Cambridge dunnock study and can help our understanding of the evolution and maintenance of various breeding systems in the animal kingdom. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Dimorphic ejaculates and sperm release strategies associated with alternative mating behaviors in the squid.

PubMed

Apostólico, Lígia H; Marian, José E A R

2017-11-01

Sperm competition is a powerful postcopulatory selective force influencing male adaptations associated with increasing fertilization success, and it is usually related to the evolution of different strategies of ejaculate expenditure between individuals. Ejaculates may also be influenced by additional selective pressures associated with sperm competition, such as timing between insemination and fertilization, female reproductive tract morphology, and fertilization environment. Also, males that adopt alternative mating tactics may face distinct sperm competition pressures, which may lead to the evolution of intraspecific diversity in ejaculates. In loliginid squids, males with alternative reproductive tactics (sneakers and consorts) differ not only in mating behavior, but also transfer spermatophores into two distinct sites within the female. Here, we compared structure and functioning of spermatophores between sneakers and consorts in the squid Doryteuthis plei applying microscopy techniques and in vitro experiments. Sneakers and consorts exhibit differences in spermatophore structure that lead to distinct spermatophoric reactions and spermatangium morphologies. Moreover, in sneakers, sperm release lasts longer and their sperm show an aggregative behavior not detected in consorts. Slow sperm release may be a strategy to guarantee longer sperm provision, given the wide interval between sneaker mating and egg release. For consorts, in turn, intense and quick sperm discharge may be advantageous, as timing between mating and egg-laying is relatively short. Within the complex squid mating system, factors such as (i) different fertilization sites and (ii) interval between mating and egg release may also influence sperm competition, and ultimately shape the evolution of divergent ejaculates between dimorphic males. © 2017 Wiley Periodicals, Inc.

On the widespread capacity for, and functional significance of, extreme inbreeding in ferns.

PubMed

Sessa, Emily B; Testo, Weston L; Watkins, James E

2016-08-01

Homosporous vascular plants utilize three different mating systems, one of which, gametophytic selfing, is an extreme form of inbreeding only possible in homosporous groups. This mating system results in complete homozygosity in all progeny and has important evolutionary and ecological implications. Ferns are the largest group of homosporous land plants, and the significance of extreme inbreeding for fern evolution has been a subject of debate for decades. We cultured gametophytes in the laboratory and quantified the relative frequencies of sporophyte production from isolated and paired gametophytes, and examined associations between breeding systems and several ecological and evolutionary traits. The majority of fern species studied show a capacity for gametophytic selfing, producing sporophytes from both isolated and paired gametophytes. While we did not follow sporophytes to maturity to investigate potential detrimental effects of homozygosity at later developmental stages, our results suggest that gametophytic selfing may have greater significance for fern evolution and diversification than has previously been realized. We present evidence from the largest study of mating behavior in ferns to date that the capacity for extreme inbreeding is prevalent in this lineage, and we discuss its implications and relevance and make recommendations for future studies of fern mating systems. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

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.

Evolution of the hemiascomycete yeasts: on life styles and the importance of inbreeding.

PubMed

Knop, Michael

2006-07-01

The term 'breeding system' is used to describe the morphological and behavioural aspects of the sexual life cycle of a species. The yeast breeding system provides three alternatives that enable hapoids to return to the diploid state that is necessary for meiosis: mating of unrelated haploids (amphimixis), mating between spores from the same tetrad (intratetrad mating, automixis) and mother daughter mating upon mating type switching (haplo-selfing). The frequency of specific mating events affects the level of heterozygosity present in individuals and the genetic diversity of populations. This review discusses the reproductive strategies of yeasts, in particular S. cerevisiae (Bakers' or budding yeast). Emphasis is put on intratetrad mating, its implication for diversity, and how the particular genome structure could have evolved to ensure the preservation of a high degree of heterozygosity in conjunction with frequent intratetrad matings. I also discuss how the ability of yeast to control the number of spores that are formed accounts for high intratetrad mating rates and for enhanced transmission of genomic variation. I extend the discussion to natural genetic variation and propose that a high level of plasticity is inherent in the yeast breeding system, which may allow variation of the breeding behaviour in accordance with the needs imposed by the environment. (c) 2006 Wiley Periodicals, Inc.

Evolution of male and female genitalia following release from sexual selection.

PubMed

Cayetano, Luis; Maklakov, Alexei A; Brooks, Robert C; Bonduriansky, Russell

2011-08-01

Despite the key functions of the genitalia in sexual interactions and fertilization, the role of sexual selection and conflict in shaping genital traits remains poorly understood. Seed beetle (Callosobruchus maculatus) males possess spines on the intromittent organ, and females possess a thickened reproductive tract wall that also bears spines. We investigated the role of sexual selection and conflict by imposing monogamous mating on eight replicate populations of this naturally polygamous insect, while maintaining eight other populations under polygamy. To establish whether responses to mating system manipulation were robust to ecological context, we simultaneously manipulated life-history selection (early/late reproduction). Over 18-21 generations, male genital spines evolved relatively reduced length in large males (i.e., shallower static allometry) in monogamous populations. Two nonintromittent male genital appendages also evolved in response to the interaction of mating system and ecology. In contrast, no detectable evolution occurred in female genitalia, consistent with the expectation of a delayed response in defensive traits. Our results support a sexually antagonistic role for the male genital spines, and demonstrate the evolution of static allometry in response to variation in sexual selection opportunity. We argue that further advances in the study of genital coevolution will require a much more detailed understanding of the functions of male and female genital traits. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

The evolution of dominance in sporophytic self-incompatibility systems. II. Mate availability and recombination.

PubMed

Schoen, Daniel J; Busch, Jeremiah W

2009-08-01

Sporophytic self-incompatibility (SSI) is a self-pollen recognition system that enforces outcrossing in plants. Recognition in SSI systems is typically controlled by a complex locus (S-locus) with separate genes that determine pollen and stigma specificity. Experimental studies show that S-alleles can be dominant, recessive, or codominant, and that the dominance level of a given S-allele can depend upon whether pollen or stigma specificity is examined. Here and in the companion paper by Llaurens and colleagues, the evolution of dominance in single-locus SSI is explored using numerical models and simulation. Particular attention is directed at factors that can cause S-allele dominance to differ in pollen versus stigma. The effect of recombination between the S-locus and modifier locus is also examined. The models predict that limitation in the number of compatible mates is required for the evolution of S-allele dominance in the stigma but not in the pollen. Tight linkage between the S-locus and modifier promotes the evolution of S-allele dominance hierarchies. Model results are interpreted with respect to published information on the molecular basis of dominance in SSI systems, and reported S-allele dominance relationships in a variety of species. These studies show that dominant S-alleles are more common in the pollen than in the stigma, a pattern that when interpreted in light of model predictions, suggests that mate limitation may be relatively infrequent in natural populations with SSI.

Evolutionary consequence of a change in life cycle complexity: A link between precocious development and evolution toward female-biased sex allocation in a hermaphroditic parasite.

PubMed

Kasl, Emily L; McAllister, Chris T; Robison, Henry W; Connior, Matthew B; Font, William F; Criscione, Charles D

2015-12-01

The evolutionary consequences of changes in the complex life cycles of parasites are not limited to the traits that directly affect transmission. For instance, mating systems that are altered due to precocious sexual maturation in what is typically regarded as an intermediate host may impact opportunities for outcrossing. In turn, reproductive traits may evolve to optimize sex allocation. Here, we test the hypothesis that sex allocation evolved toward a more female-biased function in populations of the hermaphroditic digenean trematode Alloglossidium progeneticum that can precociously reproduce in their second hosts. In these precocious populations, parasites are forced to self-fertilize as they remain encysted in their second hosts. In contrast, parasites in obligate three-host populations have more opportunities to outcross in their third host. We found strong support that in populations with precocious development, allocation to male resources was greatly reduced. We also identified a potential phenotypically plastic response in a body size sex allocation relationship that may be driven by the competition for mates. These results emphasize how changes in life cycle patterns that alter mating systems can impact the evolution of reproductive traits in parasites. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

The Mating System of the Wild-to-Domesticated Complex of Gossypium hirsutum L. Is Mixed

PubMed Central

Velázquez-López, Rebeca; Wegier, Ana; Alavez, Valeria; Pérez-López, Javier; Vázquez-Barrios, Valeria; Arroyo-Lambaer, Denise; Ponce-Mendoza, Alejandro; Kunin, William E.

2018-01-01

The domestication syndrome of many plants includes changes in their mating systems. The evolution of the latter is shaped by ecological and genetic factors that are particular to an area. Thus, the reproductive biology of wild relatives must be studied in their natural distribution to understand the mating system of a crop species as a whole. Gossypium hirsutum (upland cotton) includes both domesticated varieties and wild populations of the same species. Most studies on mating systems describe cultivated cotton as self-pollinated, while studies on pollen dispersal report outcrossing; however, the mating system of upland cotton has not been described as mixed and little is known about its wild relatives. In this study we selected two wild metapopulations for comparison with domesticated plants and one metapopulation with evidence of recent gene flow between wild relatives and the crop to evaluate the mating system of cotton’s wild-to-domesticated complex. Using classic reproductive biology methods, our data demonstrate that upland cotton presents a mixed mating system throughout the complex. Given cotton’s capacity for outcrossing, differences caused by the domestication process in cultivated individuals can have consequences for its wild relatives. This characterization of the diversity of the wild relatives in their natural distribution, as well as their interactions with the crop, will be useful to design and implement adequate strategies for conservation and biosecurity. PMID:29868048

Organization and evolution of mating-type genes in three Stagonosporopsis species causing gummy stem blight of cucurbits and leaf spot and dry rot of papaya.

PubMed

Li, Hao-Xi; Gottilla, Thomas M; Brewer, Marin Talbot

2017-10-01

Population divergence and speciation of closely related lineages can result from reproductive differences leading to genetic isolation. An increasing number of fungal diseases of plants and animals have been determined to be caused by morphologically indistinguishable species that are genetically distinct, thereby representing cryptic species. We were interested in identifying if mating systems among three Stagonosporopsis species (S. citrulli, S. cucurbitacearum, and S. caricae) causing gummy stem blight (GSB) of cucurbits or leaf spot and dry rot of papaya differed, possibly underlying species divergence. Additionally, we were interested in identifying evolutionary pressures acting on the genes controlling mating in these fungi. The mating-type loci (MAT1) of three isolates from each of the three species were identified in draft genome sequences. For the three species, MAT1 was structurally identical and contained both mating-type genes necessary for sexual reproduction, which suggests that all three species are homothallic. However, both MAT1-1-1 and MAT1-2-1 were divergent among species showing rapid evolution with a much greater number of amino acid-changing substitutions detected for the reproductive genes compared with genes flanking MAT1. Positive selection was detected in MAT1-2-1, especially in the highly conserved high mobility group (MATA_HMG-box) domain. Thus, the mating-type genes are rapidly evolving in GSB fungi, but a difference in mating systems among the three species does not underlie their divergence. Copyright © 2017 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

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.

Fungal Sex: The Mucoromycota.

PubMed

Lee, Soo Chan; Idnurm, Alexander

2017-03-01

Although at the level of resolution of genes and molecules most information about mating in fungi is from a single lineage, the Dikarya, many fundamental discoveries about mating in fungi have been made in the earlier branches of the fungi. These are nonmonophyletic groups that were once classified into the chytrids and zygomycetes. Few species in these lineages offer the potential of genetic tractability, thereby hampering the ability to identify the genes that underlie those fundamental insights. Research performed during the past decade has now established the genes required for mating type determination and pheromone synthesis in some species in the phylum Mucoromycota, especially in the order Mucorales. These findings provide striking parallels with the evolution of mating systems in the Dikarya fungi. Other discoveries in the Mucorales provide the first examples of sex-cell type identity being driven directly by a gene that confers mating type, a trait considered more of relevance to animal sex determination but difficult to investigate in animals. Despite these discoveries, there remains much to be gleaned about mating systems from these fungi.

Evolution of male strategies with sex-ratio-dependent pay-offs: connecting pair bonds with grandmothering.

PubMed

Loo, Sara L; Hawkes, Kristen; Kim, Peter S

2017-09-19

Men's provisioning of mates and offspring has been central to ideas about human evolution because paternal provisioning is absent in our closest evolutionary cousins, the great apes, and is widely assumed to result in pair bonding, which distinguishes us from them. Yet mathematical modelling has shown that paternal care does not readily spread in populations where competition for multiple mates is the common male strategy. Here we add to models that point to the mating sex ratio as an explanation for pairing as pay-offs to mate guarding rise with a male-biased sex ratio. This is of interest for human evolution because our grandmothering life history shifts the mating sex ratio from female- to male-biased. Using a difference equation model, we explore the relative pay-offs for three competing male strategies (dependant care, multiple mating, mate guarding) in response to changing adult sex ratios. When fertile females are abundant, multiple mating prevails. As they become scarce, mate guarding triumphs. The threshold for this shift depends on guarding efficiency. Combined with mating sex ratios of hunter-gatherer and chimpanzee populations, these results strengthen the hypothesis that the evolution of our grandmothering life history propelled the shift to pair bonding in the human lineage.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'. © 2017 The Author(s).

Selection on pollen and pistil traits during pollen competition is affected by both sexual conflict and mixed mating in a self-compatible herb.

PubMed

Lankinen, Åsa; Smith, Henrik G; Andersson, Stefan; Madjidian, Josefin A

2016-03-01

Although much attention has focused on the diversity of plant mating systems, only a few studies have considered the joint effects of mating system and sexual conflict in plant evolution. In mixed-mating Collinsia heterophylla, a sexual conflict over timing of stigma receptivity is proposed: pollen with a capacity to induce early onset of stigma receptivity secures paternity for early-arriving pollen (at the expense of reduced maternal seed set), whereas late onset of stigma receptivity mitigates the negative effects of early-arriving pollen. Here we investigated whether selection on pollen and pistil traits involved in sexual conflict is affected by the presence of both outcross- and self-pollen (mixed mating) during pollen competition. We conducted two-donor crosses at different floral developmental stages to explore male fitness (siring ability) and female fitness (seed set) in relation to male and female identity, pollen and pistil traits, and type of competitor pollen (outcross vs. self). Late-fertilizing pollen rather than rapidly growing pollen tubes was most successful in terms of siring success, especially in competition with self-pollen after pollination at early floral stages. Late stigma receptivity increased seed set after early-stage pollinations, in agreement with selection against antagonistic pollen. Selection on pollen and pistil traits in C. heterophylla is affected by both sexual conflict and mixed mating, suggesting the importance of jointly considering these factors in plant evolution. © 2016 Botanical Society of America.

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.

Evolution of divergent female mating preference in response to experimental sexual selection.

PubMed

Debelle, Allan; Ritchie, Michael G; Snook, Rhonda R

2014-09-01

Sexual selection is predicted to drive the coevolution of mating signals and preferences (mating traits) within populations, and could play a role in speciation if sexual isolation arises due to mating trait divergence between populations. However, few studies have demonstrated that differences in mating traits between populations result from sexual selection alone. Experimental evolution is a promising approach to directly examine the action of sexual selection on mating trait divergence among populations. We manipulated the opportunity for sexual selection (low vs. high) in populations of Drosophila pseudoobscura. Previous studies on these experimental populations have shown that sexual selection manipulation resulted in the divergence between sexual selection treatments of several courtship song parameters, including interpulse interval (IPI) which markedly influences male mating success. Here, we measure female preference for IPI using a playback design to test for preference divergence between the sexual selection treatments after 130 generations of experimental sexual selection. The results suggest that female preference has coevolved with male signal, in opposite directions between the sexual selection treatments, providing direct evidence of the ability of sexual selection to drive the divergent coevolution of mating traits between populations. We discuss the implications in the context sexual selection and speciation. © 2014 The Authors. Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Runaway sexual selection leads to good genes.

PubMed

Chandler, Christopher H; Ofria, Charles; Dworkin, Ian

2013-01-01

Mate choice and sexual displays are widespread in nature, but their evolutionary benefits remain controversial. Theory predicts these traits can be favored by runaway sexual selection, in which preference and display reinforce one another due to genetic correlation; or by good genes benefits, in which mate choice is advantageous because extreme displays indicate a well-adapted genotype. However, these hypotheses are not mutually exclusive, and the adaptive benefits underlying mate choice can themselves evolve. In particular, examining how and why sexual displays become indicators of good genes is challenging in natural systems. Here, we use experimental evolution in "digital organisms" to demonstrate the origins of condition-dependent indicator displays following their spread due to a runaway process. Surprisingly, handicap-like costs are not necessary for displays to become indicators of male viability. Instead, a pleiotropic genetic architecture underlies both displays and viability. Runaway sexual selection and good genes benefits should thus be viewed as interacting mechanisms that reinforce one another. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Sex ratio and gamete size across eastern North America in Dictyostelium discoideum, a social amoeba with three sexes.

PubMed

Douglas, T E; Strassmann, J E; Queller, D C

2016-07-01

Theory indicates that numbers of mating types should tend towards infinity or remain at two. The social amoeba, Dictyostelium discoideum, however, has three mating types. It is therefore a mystery how this species has broken the threshold of two mating types, but has not increased towards a much higher number. Frequency-dependent selection on rare types in combination with isogamy, a form of reproduction involving gametes similar in size, could explain the evolution of multiple mating types in this system. Other factors, such as drift, may be preventing the evolution of more than three. We first looked for evidence of isogamy by measuring gamete size associated with each type. We found no evidence of size dissimilarities between gametes. We then looked for evidence of balancing selection, by examining mating type distributions in natural populations and comparing genetic differentiation at the mating type locus to that at more neutral loci. We found that mating type frequency varied among the three populations we examined, with only one of the three showing an even sex ratio, which does not support balancing selection. However, we found more population structure at neutral loci than the mating type locus, suggesting that the three mating types are indeed maintained at intermediate frequencies by balancing selection. Overall, the data are consistent with balancing selection acting on D. discoideum mating types, but with a sufficiently weak rare sex advantage to allow for drift, a potential explanation for why these amoebae have only three mating types. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

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

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.

Spatial distribution and male mating success of Anopheles gambiae swarms

PubMed Central

2011-01-01

Background Anopheles gambiae mates in flight at particular mating sites over specific landmarks known as swarm markers. The swarms are composed of males; females typically approach a swarm, and leave in copula. This mating aggregation looks like a lek, but appears to lack the component of female choice. To investigate the possible mechanisms promoting the evolution of swarming in this mosquito species, we looked at the variation in mating success between swarms and discussed the factors that structure it in light of the three major lekking models, known as the female preference model, the hotspot model, and the hotshot model. Results We found substantial variation in swarm size and in mating success between swarms. A strong correlation between swarm size and mating success was observed, and consistent with the hotspot model of lek formation, the per capita mating success of individual males did not increase with swarm size. For the spatial distribution of swarms, our results revealed that some display sites were more attractive to both males and females and that females were more attracted to large swarms. While the swarm markers we recognize help us in localizing swarms, they did not account for the variation in swarm size or in the swarm mating success, suggesting that mosquitoes probably are attracted to these markers, but also perceive and respond to other aspects of the swarming site. Conclusions Characterizing the mating system of a species helps understand how this species has evolved and how selective pressures operate on male and female traits. The current study looked at male mating success of An. gambiae and discussed possible factors that account for its variation. We found that swarms of An. gambiae conform to the hotspot model of lek formation. But because swarms may lack the female choice component, we propose that the An. gambiae mating system is a lek-like system that incorporates characteristics pertaining to other mating systems such as scramble mating competition. PMID:21711542

Variation in promiscuity and sexual selection drives avian rate of Faster-Z evolution.

PubMed

Wright, Alison E; Harrison, Peter W; Zimmer, Fabian; Montgomery, Stephen H; Pointer, Marie A; Mank, Judith E

2015-03-01

Higher rates of coding sequence evolution have been observed on the Z chromosome relative to the autosomes across a wide range of species. However, despite a considerable body of theory, we lack empirical evidence explaining variation in the strength of the Faster-Z Effect. To assess the magnitude and drivers of Faster-Z Evolution, we assembled six de novo transcriptomes, spanning 90 million years of avian evolution. Our analysis combines expression, sequence and polymorphism data with measures of sperm competition and promiscuity. In doing so, we present the first empirical evidence demonstrating the positive relationship between Faster-Z Effect and measures of promiscuity, and therefore variance in male mating success. Our results from multiple lines of evidence indicate that selection is less effective on the Z chromosome, particularly in promiscuous species, and that Faster-Z Evolution in birds is due primarily to genetic drift. Our results reveal the power of mating system and sexual selection in shaping broad patterns in genome evolution. © 2015 John Wiley & Sons Ltd.

Quantitative Trait Loci Differentiating the Outbreeding Mimulus Guttatus from the Inbreeding M. Platycalyx

PubMed Central

Lin, J. Z.; Ritland, K.

1997-01-01

Theoretical predictions about the evolution of selfing depend on the genetic architecture of loci controlling selfing (monogenic vs. polygenic determination, large vs. small effect of alleles, dominance vs. recessiveness), and studies of such architecture are lacking. We inferred the genetic basis of mating system differences between the outbreeding Mimulus guttatus and the inbreeding M. platycalyx by quantitative trait locus (QTL) mapping using random amplified polymorphic DNA and isozyme markers. One to three QTL were detected for each of five mating system characters, and each QTL explained 7.6-28.6% of the phenotypic variance. Taken together, QTL accounted for up to 38% of the variation in mating system characters, and a large proportion of variation was unaccounted for. Inferred QTL often affected more than one trait, contributing to the genetic correlation between those traits. These results are consistent with the hypothesis that quantitative variation in plant mating system characters is primarily controlled by loci with small effect. PMID:9215912

Addressing the Lack of Measurement Invariance for the Measure of Acceptance of the Theory of Evolution

ERIC Educational Resources Information Center

Wagler, Amy; Wagler, Ron

2013-01-01

The Measure of Acceptance of the Theory of Evolution (MATE) was constructed to be a single-factor instrument that assesses an individual's overall acceptance of evolutionary theory. The MATE was validated and the scores resulting from the MATE were found to be reliable for the population of inservice high school biology teachers. However, many…

Reliability of the Measure of Acceptance of the Theory of Evolution (MATE) Instrument with University Students

ERIC Educational Resources Information Center

Rutledge, Michael L.; Sadler, Kim C.

2007-01-01

The Measure of Acceptance of the Theory of Evolution (MATE) instrument was initially designed to assess high school biology teachers' acceptance of evolutionary theory. To determine if the MATE instrument is reliable with university students, it was administered to students in a non-majors biology course (n = 61) twice over a 3-week period.…

Artificial selection reveals sex differences in the genetic basis of sexual attractiveness.

PubMed

Gosden, Thomas P; Reddiex, Adam J; Chenoweth, Stephen F

2018-05-07

Mutual mate choice occurs when males and females base mating decisions on shared traits. Despite increased awareness, the extent to which mutual choice drives phenotypic change remains poorly understood. When preferences in both sexes target the same traits, it is unclear how evolution will proceed and whether responses to sexual selection from male choice will match or oppose responses to female choice. Answering this question is challenging, as it requires understanding, genetic relationships between the traits targeted by choice, mating success, and, ultimately, fitness for both sexes. Addressing this, we applied artificial selection to the cuticular hydrocarbons of the fly Drosophila serrata that are targeted by mutual choice and tracked evolutionary changes in males and females alongside changes in mating success. After 10 generations, significant trait evolution occurred in both sexes, but intriguingly there were major sex differences in the associated fitness consequences. Sexually selected trait evolution in males led to a genetically based increase in male mating success. By contrast, although trait evolution also occurred in females, there was no change in mating success. Our results suggest that phenotypic sexual selection on females from male choice is environmentally, rather than genetically, generated. Thus, compared with female choice, male choice is at best a weak driver of signal trait evolution in this species. Instead, the evolution of apparent female ornamentation seems more likely due to a correlated response to sexual selection on males and possibly other forms of natural selection.

The evolution of postpairing male mate choice.

PubMed

Lyu, Nan; Servedio, Maria R; Lloyd, Huw; Sun, Yue-Hua

2017-06-01

An increasing number of empirical studies in animals have demonstrated male mate choice. However, little is known about the evolution of postpairing male choice, specifically which occurs by differential allocation of male parental care in response to female signals. We use a population genetic model to examine whether such postpairing male mate choice can evolve when males face a trade-off between parental care and extra-pair copulations (EPCs). Specifically, we assume that males allocate more effort to providing parental care when mated to preferred (signaling) females, but they are then unable to allocate additional effort to seek EPCs. We find that both male preference and female signaling can evolve in this situation, under certain conditions. First, this evolution requires a relatively large difference in parental investment between males mated to preferred versus nonpreferred females. Second, whether male choice and female signaling alleles become fixed in a population versus cycle in their frequencies depends on the additional fecundity benefits from EPCs that are gained by choosy males. Third, less costly female signals enable both signaling and choice alleles to evolve under more relaxed conditions. Our results also provide a new insight into the evolution of sexual conflict over parental care. © 2017 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Experience of mating rivals causes males to modulate sperm transfer in the fly Drosophila pseudoobscura.

PubMed

Price, Tom A R; Lizé, Anne; Marcello, Marco; Bretman, Amanda

2012-12-01

Male responses to risk of sperm competition play an important role in sexual selection, sexual conflict, and the evolution of mating systems. Such responses can combine behavioural and physiological processes, and can be mediated through different components of the ejaculate such as sperm numbers and seminal proteins. An additional level of ejaculate complexity is sperm heteromorphism, with the inclusion of non-fertilising parasperm in the ejaculate. We now test the response to rivals in a sperm heteromorphic species, Drosophila pseudoobscura, measuring the behavioural response and sperm transfer and, crucially, relating these to short-term fitness. Males respond to exposure to conspecific rivals by increasing mating duration, but do not respond to heterospecific rivals. In addition, after exposure to a conspecific rival, males increased the transfer of fertilising eusperm, but not non-fertilising parasperm. Males exposed to a conspecific rival also achieve higher offspring production. This suggests that the evolution of parasperm in flies was not driven by sperm competition and adds to the increasing evidence that males can make extremely sophisticated responses to mating competition. Copyright © 2012. Published by Elsevier Ltd.

Genetic diversity promotes homeostasis in insect colonies.

PubMed

Oldroyd, Benjamin P; Fewell, Jennifer H

2007-08-01

Although most insect colonies are headed by a singly mated queen, some ant, wasp and bee taxa have evolved high levels of multiple mating or 'polyandry'. We argue here that a contributing factor towards the evolution of polyandry is that the resulting genetic diversity within colonies provides them with a system of genetically based task specialization, enabling them to respond resiliently to environmental perturbation. An alternate view is that genetic contributions to task specialization are a side effect of multiple mating, which evolved through other causes, and that genetically based task specialization now makes little or no contribution to colony fitness.

Mating system shifts and transposable element evolution in the plant genus Capsella.

PubMed

Agren, J Ågren; Wang, Wei; Koenig, Daniel; Neuffer, Barbara; Weigel, Detlef; Wright, Stephen I

2014-07-16

Despite having predominately deleterious fitness effects, transposable elements (TEs) are major constituents of eukaryote genomes in general and of plant genomes in particular. Although the proportion of the genome made up of TEs varies at least four-fold across plants, the relative importance of the evolutionary forces shaping variation in TE abundance and distributions across taxa remains unclear. Under several theoretical models, mating system plays an important role in governing the evolutionary dynamics of TEs. Here, we use the recently sequenced Capsella rubella reference genome and short-read whole genome sequencing of multiple individuals to quantify abundance, genome distributions, and population frequencies of TEs in three recently diverged species of differing mating system, two self-compatible species (C. rubella and C. orientalis) and their self-incompatible outcrossing relative, C. grandiflora. We detect different dynamics of TE evolution in our two self-compatible species; C. rubella shows a small increase in transposon copy number, while C. orientalis shows a substantial decrease relative to C. grandiflora. The direction of this change in copy number is genome wide and consistent across transposon classes. For insertions near genes, however, we detect the highest abundances in C. grandiflora. Finally, we also find differences in the population frequency distributions across the three species. Overall, our results suggest that the evolution of selfing may have different effects on TE evolution on a short and on a long timescale. Moreover, cross-species comparisons of transposon abundance are sensitive to reference genome bias, and efforts to control for this bias are key when making comparisons across species.

X-MATE: a flexible system for mapping short read data

PubMed Central

Pearson, John V.; Cloonan, Nicole; Grimmond, Sean M.

2011-01-01

Summary: Accurate and complete mapping of short-read sequencing to a reference genome greatly enhances the discovery of biological results and improves statistical predictions. We recently presented RNA-MATE, a pipeline for the recursive mapping of RNA-Seq datasets. With the rapid increase in genome re-sequencing projects, progression of available mapping software and the evolution of file formats, we now present X-MATE, an updated version of RNA-MATE, capable of mapping both RNA-Seq and DNA datasets and with improved performance, output file formats, configuration files, and flexibility in core mapping software. Availability: Executables, source code, junction libraries, test data and results and the user manual are available from http://grimmond.imb.uq.edu.au/X-MATE/. Contact: n.cloonan@uq.edu.au; s.grimmond@uq.edu.au Supplementary information: Supplementary data are available at Bioinformatics Online. PMID:21216778

Heterozygosity-based assortative mating in blue tits (Cyanistes caeruleus): implications for the evolution of mate choice

PubMed Central

García-Navas, Vicente; Ortego, Joaquín; Sanz, Juan José

2009-01-01

The general hypothesis of mate choice based on non-additive genetic traits suggests that individuals would gain important benefits by choosing genetically dissimilar mates (compatible mate hypothesis) and/or more heterozygous mates (heterozygous mate hypothesis). In this study, we test these hypotheses in a socially monogamous bird, the blue tit (Cyanistes caeruleus). We found no evidence for a relatedness-based mating pattern, but heterozygosity was positively correlated between social mates, suggesting that blue tits may base their mating preferences on partner's heterozygosity. We found evidence that the observed heterozygosity-based assortative mating could be maintained by both direct and indirect benefits. Heterozygosity reflected individual quality in both sexes: egg production and quality increased with female heterozygosity while more heterozygous males showed higher feeding rates during the brood-rearing period. Further, estimated offspring heterozygosity correlated with both paternal and maternal heterozygosity, suggesting that mating with heterozygous individuals can increase offspring genetic quality. Finally, plumage crown coloration was associated with male heterozygosity, and this could explain unanimous mate preferences for highly heterozygous and more ornamented individuals. Overall, this study suggests that non-additive genetic traits may play an important role in the evolution of mating preferences and offers empirical support to the resolution of the lek paradox from the perspective of the heterozygous mate hypothesis. PMID:19474042

Female Mate Choice Can Drive the Evolution of High Frequency Echolocation in Bats: A Case Study with Rhinolophus mehelyi

PubMed Central

Puechmaille, Sébastien J.; Borissov, Ivailo M.; Zsebok, Sándor; Allegrini, Benjamin; Hizem, Mohammed; Kuenzel, Sven; Schuchmann, Maike; Teeling, Emma C.

2014-01-01

Animals employ an array of signals (i.e. visual, acoustic, olfactory) for communication. Natural selection favours signals, receptors, and signalling behaviour that optimise the received signal relative to background noise. When the signal is used for more than one function, antagonisms amongst the different signalling functions may constrain the optimisation of the signal for any one function. Sexual selection through mate choice can strongly modify the effects of natural selection on signalling systems ultimately causing maladaptive signals to evolve. Echolocating bats represent a fascinating group in which to study the evolution of signalling systems as unlike bird songs or frog calls, echolocation has a dual role in foraging and communication. The function of bat echolocation is to generate echoes that the calling bat uses for orientation and food detection with call characteristics being directly related to the exploitation of particular ecological niches. Therefore, it is commonly assumed that echolocation has been shaped by ecology via natural selection. Here we demonstrate for the first time using a novel combined behavioural, ecological and genetic approach that in a bat species, Rhinolophus mehelyi: (1) echolocation peak frequency is an honest signal of body size; (2) females preferentially select males with high frequency calls during the mating season; (3) high frequency males sire more off-spring, providing evidence that echolocation calls may play a role in female mate choice. Our data refute the sole role of ecology in the evolution of echolocation and highlight the antagonistic interplay between natural and sexual selection in shaping acoustic signals. PMID:25075972

Female mate choice can drive the evolution of high frequency echolocation in bats: a case study with Rhinolophus mehelyi.

PubMed

Puechmaille, Sébastien J; Borissov, Ivailo M; Zsebok, Sándor; Allegrini, Benjamin; Hizem, Mohammed; Kuenzel, Sven; Schuchmann, Maike; Teeling, Emma C; Siemers, Björn M

2014-01-01

Animals employ an array of signals (i.e. visual, acoustic, olfactory) for communication. Natural selection favours signals, receptors, and signalling behaviour that optimise the received signal relative to background noise. When the signal is used for more than one function, antagonisms amongst the different signalling functions may constrain the optimisation of the signal for any one function. Sexual selection through mate choice can strongly modify the effects of natural selection on signalling systems ultimately causing maladaptive signals to evolve. Echolocating bats represent a fascinating group in which to study the evolution of signalling systems as unlike bird songs or frog calls, echolocation has a dual role in foraging and communication. The function of bat echolocation is to generate echoes that the calling bat uses for orientation and food detection with call characteristics being directly related to the exploitation of particular ecological niches. Therefore, it is commonly assumed that echolocation has been shaped by ecology via natural selection. Here we demonstrate for the first time using a novel combined behavioural, ecological and genetic approach that in a bat species, Rhinolophus mehelyi: (1) echolocation peak frequency is an honest signal of body size; (2) females preferentially select males with high frequency calls during the mating season; (3) high frequency males sire more off-spring, providing evidence that echolocation calls may play a role in female mate choice. Our data refute the sole role of ecology in the evolution of echolocation and highlight the antagonistic interplay between natural and sexual selection in shaping acoustic signals.

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

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.

Mating systems, reproductive success, and sexual selection in secretive species: a case study of the western diamond-backed rattlesnake, Crotalus atrox.

PubMed

Clark, Rulon W; Schuett, Gordon W; Repp, Roger A; Amarello, Melissa; Smith, Charles F; Herrmann, Hans-Werner

2014-01-01

Long-term studies of individual animals in nature contribute disproportionately to our understanding of the principles of ecology and evolution. Such field studies can benefit greatly from integrating the methods of molecular genetics with traditional approaches. Even though molecular genetic tools are particularly valuable for species that are difficult to observe directly, they have not been widely adopted. Here, we used molecular genetic techniques in a 10-year radio-telemetric investigation of the western diamond-backed rattlesnake (Crotalus atrox) for an analysis of its mating system and to measure sexual selection. Specifically, we used microsatellite markers to genotype 299 individuals, including neonates from litters of focal females to ascertain parentage using full-pedigree likelihood methods. We detected high levels of multiple paternity within litters, yet found little concordance between paternity and observations of courtship and mating behavior. Larger males did not father significantly more offspring, but we found evidence for size-specific male-mating strategies, with larger males guarding females for longer periods in the mating seasons. Moreover, the spatial proximity of males to mothers was significantly associated with reproductive success. Overall, our field observations alone would have been insufficient to quantitatively measure the mating system of this population of C. atrox, and we thus urge more widespread adoption of molecular tools by field researchers studying the mating systems and sexual selection of snakes and other secretive taxa.

Mating Systems, Reproductive Success, and Sexual Selection in Secretive Species: A Case Study of the Western Diamond-Backed Rattlesnake, Crotalus atrox

PubMed Central

Clark, Rulon W.; Schuett, Gordon W.; Repp, Roger A.; Amarello, Melissa; Smith, Charles F.; Herrmann, Hans-Werner

2014-01-01

Long-term studies of individual animals in nature contribute disproportionately to our understanding of the principles of ecology and evolution. Such field studies can benefit greatly from integrating the methods of molecular genetics with traditional approaches. Even though molecular genetic tools are particularly valuable for species that are difficult to observe directly, they have not been widely adopted. Here, we used molecular genetic techniques in a 10-year radio-telemetric investigation of the western diamond-backed rattlesnake (Crotalus atrox) for an analysis of its mating system and to measure sexual selection. Specifically, we used microsatellite markers to genotype 299 individuals, including neonates from litters of focal females to ascertain parentage using full-pedigree likelihood methods. We detected high levels of multiple paternity within litters, yet found little concordance between paternity and observations of courtship and mating behavior. Larger males did not father significantly more offspring, but we found evidence for size-specific male-mating strategies, with larger males guarding females for longer periods in the mating seasons. Moreover, the spatial proximity of males to mothers was significantly associated with reproductive success. Overall, our field observations alone would have been insufficient to quantitatively measure the mating system of this population of C. atrox, and we thus urge more widespread adoption of molecular tools by field researchers studying the mating systems and sexual selection of snakes and other secretive taxa. PMID:24598810

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.

EVOLUTION, PHYLOGENY, SEXUAL DIMORPHISM AND MATING SYSTEM IN THE GRACKLES (QUISCALUS SPP.: ICTERINAE).

PubMed

Björklund, Mats

1991-05-01

According to theory, two consequences of sexual selection are sexual dimorphism in size and secondary sexual characteristics, due to either intra- or intersexual selection. In this paper I suggest three criteria for the test of an evolutionary hypothesis involving quantitative morphological characters. First, the postulated change must be shown to have occurred in evolutionary time. Second, this change must be positively correlated with a change in the proposed selective agent. Third, given two taxa with different degrees of sexual size dimorphism and different mating system, the possible influence of drift must be rejected. If the hypothesis is not rejected by these three criteria, then we still have no proof of causality, but we can at least be more confident about its plausibility. This is applied to the particular hypothesis that sexual dimorphism in the Boat-tailed and Great-tailed grackles (Quiscalus spp; Icterinae; Aves) is caused by the highly polygynous mating system in these species. In relation to an outgroup, both species have increased disproportionately in male tarsus and tail size, creating an increased sexual dimorphism. This has cooccurred with the evolution of their particular mating system. However, the variance among species in male tarsus size can be accounted for by drift, and need not be a result of selection for increased size. In contrast, the variance among species in male tail size was much larger than expected under a null model of drift, indicating directional selection for long tails. The variance in female tail size was not larger than expected by drift, whereas the variance in female tarsus size was in fact lower than expected by drift, indicating stabilizing selection. The data are consistent with the hypothesis with regard to tail size, but not with regard to body size. © 1991 The Society for the Study of Evolution.

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

Cross-species correlation between queen mating numbers and worker ovary sizes suggests kin conflict may influence ovary size evolution in honeybees

NASA Astrophysics Data System (ADS)

Rueppell, Olav; Phaincharoen, Mananya; Kuster, Ryan; Tingek, Salim

2011-09-01

During social evolution, the ovary size of reproductively specialized honey bee queens has dramatically increased while their workers have evolved much smaller ovaries. However, worker division of labor and reproductive competition under queenless conditions are influenced by worker ovary size. Little comparative information on ovary size exists in the different honey bee species. Here, we report ovariole numbers of freshly dissected workers from six Apis species from two locations in Southeast Asia. The average number of worker ovarioles differs significantly among species. It is strongly correlated with the average mating number of queens, irrespective of body size. Apis dorsata, in particular, is characterized by numerous matings and very large worker ovaries. The relation between queen mating number and ovary size across the six species suggests that individual selection via reproductive competition plays a role in worker ovary size evolution. This indicates that genetic diversity, generated by multiple mating, may bear a fitness cost at the colony level.

Aesthetic evolution by mate choice: Darwin's really dangerous idea.

PubMed

Prum, Richard O

2012-08-19

Darwin proposed an explicitly aesthetic theory of sexual selection in which he described mate preferences as a 'taste for the beautiful', an 'aesthetic capacity', etc. These statements were not merely colourful Victorian mannerisms, but explicit expressions of Darwin's hypothesis that mate preferences can evolve for arbitrarily attractive traits that do not provide any additional benefits to mate choice. In his critique of Darwin, A. R. Wallace proposed an entirely modern mechanism of mate preference evolution through the correlation of display traits with male vigour or viability, but he called this mechanism natural selection. Wallace's honest advertisement proposal was stridently anti-Darwinian and anti-aesthetic. Most modern sexual selection research relies on essentially the same Neo-Wallacean theory renamed as sexual selection. I define the process of aesthetic evolution as the evolution of a communication signal through sensory/cognitive evaluation, which is most elaborated through coevolution of the signal and its evaluation. Sensory evaluation includes the possibility that display traits do not encode information that is being assessed, but are merely preferred. A genuinely Darwinian, aesthetic theory of sexual selection requires the incorporation of the Lande-Kirkpatrick null model into sexual selection research, but also encompasses the possibility of sensory bias, good genes and direct benefits mechanisms.

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.

Estimation of mating system parameters in an evolving gynodioecous population of cultivated sunflower (Helianthus annuus L.)

PubMed Central

Roumet, M; Ostrowski, M-F; David, J; Tollon, C; Muller, M-H

2012-01-01

Cultivated plants have been molded by human-induced selection, including manipulations of the mating system in the twentieth century. How these manipulations have affected realized parameters of the mating system in freely evolving cultivated populations is of interest for optimizing the management of breeding populations, predicting the fate of escaped populations and providing material for experimental evolution studies. To produce modern varieties of sunflower (Helianthus annuus L.), self-incompatibility has been broken, recurrent generations of selfing have been performed and male sterility has been introduced. Populations deriving from hybrid-F1 varieties are gynodioecious because of the segregation of a nuclear restorer of male fertility. Using both phenotypic and genotypic data at 11 microsatellite loci, we analyzed the consanguinity status of plants of the first three generations of such a population and estimated parameters related to the mating system. We showed that the resource reallocation to seed in male-sterile individuals was not significant, that inbreeding depression on seed production averaged 15–20% and that cultivated sunflower had acquired a mixed-mating system, with ∼50% of selfing among the hermaphrodites. According to theoretical models, the female advantage and the inbreeding depression at the seed production stage were too low to allow the persistence of male sterility. We discuss our methods of parameter estimation and the potential of such study system in evolutionary biology. PMID:21915147

Mainstreaming Caenorhabditis elegans in experimental evolution.

PubMed

Gray, Jeremy C; Cutter, Asher D

2014-03-07

Experimental evolution provides a powerful manipulative tool for probing evolutionary process and mechanism. As this approach to hypothesis testing has taken purchase in biology, so too has the number of experimental systems that use it, each with its own unique strengths and weaknesses. The depth of biological knowledge about Caenorhabditis nematodes, combined with their laboratory tractability, positions them well for exploiting experimental evolution in animal systems to understand deep questions in evolution and ecology, as well as in molecular genetics and systems biology. To date, Caenorhabditis elegans and related species have proved themselves in experimental evolution studies of the process of mutation, host-pathogen coevolution, mating system evolution and life-history theory. Yet these organisms are not broadly recognized for their utility for evolution experiments and remain underexploited. Here, we outline this experimental evolution work undertaken so far in Caenorhabditis, detail simple methodological tricks that can be exploited and identify research areas that are ripe for future discovery.

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.

Sexual selection and mate choice.

PubMed

Andersson, Malte; Simmons, Leigh W

2006-06-01

The past two decades have seen extensive growth of sexual selection research. Theoretical and empirical work has clarified many components of pre- and postcopulatory sexual selection, such as aggressive competition, mate choice, sperm utilization and sexual conflict. Genetic mechanisms of mate choice evolution have been less amenable to empirical testing, but molecular genetic analyses can now be used for incisive experimentation. Here, we highlight some of the currently debated areas in pre- and postcopulatory sexual selection. We identify where new techniques can help estimate the relative roles of the various selection mechanisms that might work together in the evolution of mating preferences and attractive traits, and in sperm-egg interactions.

Divergence and evolution of assortative mating in a polygenic trait model of speciation with gene flow.

PubMed

Sachdeva, Himani; Barton, Nicholas H

2017-06-01

Assortative mating is an important driver of speciation in populations with gene flow and is predicted to evolve under certain conditions in few-locus models. However, the evolution of assortment is less understood for mating based on quantitative traits, which are often characterized by high genetic variability and extensive linkage disequilibrium between trait loci. We explore this scenario for a two-deme model with migration, by considering a single polygenic trait subject to divergent viability selection across demes, as well as assortative mating and sexual selection within demes, and investigate how trait divergence is shaped by various evolutionary forces. Our analysis reveals the existence of sharp thresholds of assortment strength, at which divergence increases dramatically. We also study the evolution of assortment via invasion of modifiers of mate discrimination and show that the ES assortment strength has an intermediate value under a range of migration-selection parameters, even in diverged populations, due to subtle effects which depend sensitively on the extent of phenotypic variation within these populations. The evolutionary dynamics of the polygenic trait is studied using the hypergeometric and infinitesimal models. We further investigate the sensitivity of our results to the assumptions of the hypergeometric model, using individual-based simulations. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

SLE as a Mating of Trees in Euclidean Geometry

NASA Astrophysics Data System (ADS)

Holden, Nina; Sun, Xin

2018-05-01

The mating of trees approach to Schramm-Loewner evolution (SLE) in the random geometry of Liouville quantum gravity (LQG) has been recently developed by Duplantier et al. (Liouville quantum gravity as a mating of trees, 2014. arXiv:1409.7055). In this paper we consider the mating of trees approach to SLE in Euclidean geometry. Let {η} be a whole-plane space-filling SLE with parameter {κ > 4} , parameterized by Lebesgue measure. The main observable in the mating of trees approach is the contour function, a two-dimensional continuous process describing the evolution of the Minkowski content of the left and right frontier of {η} . We prove regularity properties of the contour function and show that (as in the LQG case) it encodes all the information about the curve {η} . We also prove that the uniform spanning tree on {Z^2} converges to SLE8 in the natural topology associated with the mating of trees approach.

The evolution of sex differences in mate searching when females benefit: new theory and a comparative test.

PubMed

McCartney, J; Kokko, H; Heller, K-G; Gwynne, D T

2012-03-22

Sexual selection is thought to have led to searching as a profitable, but risky way of males obtaining mates. While there is great variation in which sex searches, previous theory has not considered search evolution when both males and females benefit from multiple mating. We present new theory and link it with data to bridge this gap. Two different search protocols exist between species in the bush-cricket genus Poecilimon (Orthoptera): females search for calling males, or males search for calling females. Poecilimon males also transfer a costly nuptial food gift to their mates during mating. We relate variations in searching protocols to variation in nuptial gift size among 32 Poecilimon taxa. As predicted, taxa where females search produce significantly larger nuptial gifts than those where males search. Our model and results show that search roles can reverse when multiple mating brings about sufficiently strong material benefits to females.

Dangerous mating systems: signal complexity, signal content and neural capacity in spiders.

PubMed

Herberstein, M E; Wignall, A E; Hebets, E A; Schneider, J M

2014-10-01

Spiders are highly efficient predators in possession of exquisite sensory capacities for ambushing prey, combined with machinery for launching rapid and determined attacks. As a consequence, any sexually motivated approach carries a risk of ending up as prey rather than as a mate. Sexual selection has shaped courtship to effectively communicate the presence, identity, motivation and/or quality of potential mates, which help ameliorate these risks. Spiders communicate this information via several sensory channels, including mechanical (e.g. vibrational), visual and/or chemical, with examples of multimodal signalling beginning to emerge in the literature. The diverse environments that spiders inhabit have further shaped courtship content and form. While our understanding of spider neurobiology remains in its infancy, recent studies are highlighting the unique and considerable capacities of spiders to process and respond to complex sexual signals. As a result, the dangerous mating systems of spiders are providing important insights into how ecology shapes the evolution of communication systems, with future work offering the potential to link this complex communication with its neural processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Paternal care and litter size coevolution in mammals.

PubMed

Stockley, Paula; Hobson, Liane

2016-04-27

Biparental care of offspring occurs in diverse mammalian genera and is particularly common among species with socially monogamous mating systems. Despite numerous well-documented examples, however, the evolutionary causes and consequences of paternal care in mammals are not well understood. Here, we investigate the evolution of paternal care in relation to offspring production. Using comparative analyses to test for evidence of evolutionary associations between male care and life-history traits, we explore if biparental care is likely to have evolved because of the importance of male care to offspring survival, or if evolutionary increases in offspring production are likely to result from the evolution of biparental care. Overall, we find no evidence that paternal care has evolved in response to benefits of supporting females to rear particularly costly large offspring or litters. Rather, our findings suggest that increases in offspring production are more likely to follow the evolution of paternal care, specifically where males contribute depreciable investment such as provisioning young. Through coevolution with litter size, we conclude that paternal care in mammals is likely to play an important role in stabilizing monogamous mating systems and could ultimately promote the evolution of complex social behaviours. © 2016 The Authors.

Paternal care and litter size coevolution in mammals

PubMed Central

Hobson, Liane

2016-01-01

Biparental care of offspring occurs in diverse mammalian genera and is particularly common among species with socially monogamous mating systems. Despite numerous well-documented examples, however, the evolutionary causes and consequences of paternal care in mammals are not well understood. Here, we investigate the evolution of paternal care in relation to offspring production. Using comparative analyses to test for evidence of evolutionary associations between male care and life-history traits, we explore if biparental care is likely to have evolved because of the importance of male care to offspring survival, or if evolutionary increases in offspring production are likely to result from the evolution of biparental care. Overall, we find no evidence that paternal care has evolved in response to benefits of supporting females to rear particularly costly large offspring or litters. Rather, our findings suggest that increases in offspring production are more likely to follow the evolution of paternal care, specifically where males contribute depreciable investment such as provisioning young. Through coevolution with litter size, we conclude that paternal care in mammals is likely to play an important role in stabilizing monogamous mating systems and could ultimately promote the evolution of complex social behaviours. PMID:27097924

A key ecological trait drove the evolution of biparental care and monogamy in an amphibian.

PubMed

Brown, Jason L; Morales, Victor; Summers, Kyle

2010-04-01

Linking specific ecological factors to the evolution of parental care pattern and mating system is a difficult task of key importance. We provide evidence from comparative analyses that an ecological factor (breeding pool size) is associated with the evolution of parental care across all frogs. We further show that the most intensive form of parental care (trophic egg feeding) evolved in concert with the use of small pools for tadpole deposition and that egg feeding was associated with the evolution of biparental care. Previous research on two Peruvian poison frogs (Ranitomeya imitator and Ranitomeya variabilis) revealed similar life histories, with the exception of breeding pool size. This key ecological difference led to divergence in parental care patterns and mating systems. We present ecological field experiments that demonstrate that biparental care is essential to tadpole survival in small (but not large) pools. Field observations demonstrate social monogamy in R. imitator, the species that uses small pools. Molecular analyses demonstrate genetic monogamy in R. imitator, the first example of genetic monogamy in an amphibian. In total, this evidence constitutes the most complete documentation to date that a single ecological factor drove the evolution of biparental care and genetic and social monogamy in an animal.

The scope and strength of sex-specific selection in genome evolution

PubMed Central

Wright, A E; Mank, J E

2013-01-01

Males and females share the vast majority of their genomes and yet are often subject to different, even conflicting, selection. Genomic and transcriptomic developments have made it possible to assess sex-specific selection at the molecular level, and it is clear that sex-specific selection shapes the evolutionary properties of several genomic characteristics, including transcription, post-transcriptional regulation, imprinting, genome structure and gene sequence. Sex-specific selection is strongly influenced by mating system, which also causes neutral evolutionary changes that affect different regions of the genome in different ways. Here, we synthesize theoretical and molecular work in order to provide a cohesive view of the role of sex-specific selection and mating system in genome evolution. We also highlight the need for a combined approach, incorporating both genomic data and experimental phenotypic studies, in order to understand precisely how sex-specific selection drives evolutionary change across the genome. PMID:23848139

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.

Experimental evolution of female traits under different levels of intersexual conflict in Drosophila melanogaster.

PubMed

Nandy, B; Gupta, V; Udaykumar, N; Samant, M A; Sen, S; Prasad, N G

2014-02-01

A number of studies have documented the evolution of female resistance to mate-harm in response to the alteration of intersexual conflict in the populations. However, the life-history consequence of such evolution is still a subject of debate. In this study, we subjected replicate populations of Drosophila melanogaster to different levels of sexual conflict (generated by altering the operational sex ratio) for over 45 generations. Our results suggest that females from populations experiencing higher level of intersexual conflict evolved increased resistance to mate-harm, in terms of both longevity and progeny production. Females from the populations with low conflict were significantly heavier at eclosion and were more susceptible to mate-harm in terms of progeny production under continuous exposure to the males. However, these females produced more progeny upon single mating and had significantly higher longevity in absence of any male exposure-a potential evidence of trade-offs between resistance-related traits and other life-history traits, such as fecundity and longevity. We also report tentative evidence, suggesting an increased male cost of interacting with more resistant females. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Aesthetic evolution by mate choice: Darwin's really dangerous idea

PubMed Central

Prum, Richard O.

2012-01-01

Darwin proposed an explicitly aesthetic theory of sexual selection in which he described mate preferences as a ‘taste for the beautiful’, an ‘aesthetic capacity’, etc. These statements were not merely colourful Victorian mannerisms, but explicit expressions of Darwin's hypothesis that mate preferences can evolve for arbitrarily attractive traits that do not provide any additional benefits to mate choice. In his critique of Darwin, A. R. Wallace proposed an entirely modern mechanism of mate preference evolution through the correlation of display traits with male vigour or viability, but he called this mechanism natural selection. Wallace's honest advertisement proposal was stridently anti-Darwinian and anti-aesthetic. Most modern sexual selection research relies on essentially the same Neo-Wallacean theory renamed as sexual selection. I define the process of aesthetic evolution as the evolution of a communication signal through sensory/cognitive evaluation, which is most elaborated through coevolution of the signal and its evaluation. Sensory evaluation includes the possibility that display traits do not encode information that is being assessed, but are merely preferred. A genuinely Darwinian, aesthetic theory of sexual selection requires the incorporation of the Lande–Kirkpatrick null model into sexual selection research, but also encompasses the possibility of sensory bias, good genes and direct benefits mechanisms. PMID:22777014

Breeding systems, hybridization and continuing evolution in Avon Gorge Sorbus

PubMed Central

Ludwig, Shanna; Robertson, Ashley; Rich, Timothy C. G.; Djordjević, Milena; Cerović, Radosav; Houston, Libby; Harris, Stephen A.; Hiscock, Simon J.

2013-01-01

Background and Aims Interspecific hybridization and polyploidy are key processes in plant evolution and are responsible for ongoing genetic diversification in the genus Sorbus (Rosaceae). The Avon Gorge, Bristol, UK, is a world ‘hotspot’ for Sorbus diversity and home to diploid sexual species and polyploid apomictic species. This research investigated how mating system variation, hybridization and polyploidy interact to generate this biological diversity. Methods Mating systems of diploid, triploid and tetraploid Sorbus taxa were analysed using pollen tube growth and seed set assays from controlled pollinations, and parent–offspring genotyping of progeny from open and manual pollinations. Key Results Diploid Sorbus are outcrossing and self-incompatible (SI). Triploid taxa are pseudogamous apomicts and genetically invariable, but because they also display self-incompatibility, apomictic seed set requires pollen from other Sorbus taxa – a phenomenon which offers direct opportunities for hybridization. In contrast tetraploid taxa are pseudogamous but self-compatible, so do not have the same obligate requirement for intertaxon pollination. Conclusions The mating inter-relationships among Avon Gorge Sorbus taxa are complex and are the driving force for hybridization and ongoing genetic diversification. In particular, the presence of self-incompatibility in triploid pseudogamous apomicts imposes a requirement for interspecific cross-pollination, thereby facilitating continuing diversification and evolution through rare sexual hybridization events. This is the first report of naturally occurring pseudogamous apomictic SI plant populations, and we suggest that interspecific pollination, in combination with a relaxed endosperm balance requirement, is the most likely route to the persistence of these populations. We propose that Avon Gorge Sorbus represents a model system for studying the establishment and persistence of SI apomicts in natural populations. PMID:23408832

The role of sexual preferences in intrasexual female competition

PubMed Central

2012-01-01

Background While search costs have long been understood to affect the evolution of female preference, other costs associated with mating have been the focus of much less attention. Here I consider a novel mate choice cost: female-female intrasexual competition, that is, when females compete with each other for mates. This competition results in cost to female fecundity, such as a reduction in fertility due to decreased direct benefits, sperm limitation, or time and resources spent competing for a mate. I asked if female-female competition affects the evolution of preferences, and further, if the presence of multiple, different, preferences in a population can reduce competitive costs. Results Using population genetic models of preference and trait evolution, I found that intrasexual competition leads to direct selection against female preferences, and restricts the parameter space under which preference may evolve. I also examined how multiple, different, preferences affected preference evolution with female intrasexual competition. Conclusions Multiple preferences primarily serve to increase competitive costs and decrease the range of parameters under which preferences may evolve. PMID:23148567

Spatially heterogeneous environmental selection strengthens evolution of reproductively isolated populations in a Dobzhansky-Muller system of hybrid incompatibility

Treesearch

Samuel A. Cushman; Erin L. Landguth

2016-01-01

Within-species hybrid incompatibility can arise when combinations of alleles at more than one locus have low fitness but where possession of one of those alleles has little or no fitness consequence for the carriers. Limited dispersal with small numbers of mate potentials alone can lead to the evolution of clusters of reproductively isolated genotypes despite...

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.

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.

Use of noninvasive ‘bug-eggs’ to enable comparative inferences on genetic mating system with and without parental information: A study in a cattle egret colony

PubMed Central

de Souza, Elaine Dantas; Moralez-Silva, Emmanuel; Valdes, Talita Alvarenga; Cortiço Corrêa Rodrigues, Vera Lúcia

2017-01-01

Colonial waterbirds such as herons, egrets and spoonbills exhibit ecological characteristics that could have promoted the evolution of conspecific brood parasitism and extra-pair copulation. However, an adequate characterization of the genetic mating systems of this avian group has been hindered by the lack of samples of elusive candidate parents which precluded conducting conventional parentage allocation tests. Here, we investigate the genetic mating system of the invasive cattle egret using hematophagous insects contained in fake eggs to collect blood from incubating adults in a wild breeding colony. We tested a protocol with a previously unused Neotropical Triatominae, Panstrongylus megistus, obtained blood samples from males and females in 31 nests built on trees, drew blood from 89 nestlings at those nests, and genotyped all samples at 14 microsatellite loci, including six new species-specific loci. We comparatively addressed the performance of parentage allocation versus kinship classification of nestlings to infer the genetic mating system of cattle egrets. In line with previous behavioral observations, we found evidence in support of a non-monogamous genetic mating system, including extra-pair paternity (EPP) and conspecific brood parasitism (CBP). Parentage allocation tests detected a higher percentage of nests with alternative reproductive tactics (EPP: 61.7%; CBP: 64.5%) than the kinship classification method (EPP: 50.0%; CBP: 43.3%). Overall, these results indicate that rates of alternative reproductive tactics inferred in the absence of parental genetic information could be underestimated and should be interpreted with caution. This study highlights the importance of incorporating samples from candidate parents to adequately determine the genetic mating system of a species. We expand knowledge on the reproductive tactics of colonial waterbirds, contributing novel data on the genetic mating system of the cattle egret, valuable for the design of management strategies for this invasive bird. PMID:28854191

Use of noninvasive 'bug-eggs' to enable comparative inferences on genetic mating system with and without parental information: A study in a cattle egret colony.

PubMed

Miño, Carolina Isabel; de Souza, Elaine Dantas; Moralez-Silva, Emmanuel; Valdes, Talita Alvarenga; Cortiço Corrêa Rodrigues, Vera Lúcia; Del Lama, Sílvia Nassif

2017-01-01

Colonial waterbirds such as herons, egrets and spoonbills exhibit ecological characteristics that could have promoted the evolution of conspecific brood parasitism and extra-pair copulation. However, an adequate characterization of the genetic mating systems of this avian group has been hindered by the lack of samples of elusive candidate parents which precluded conducting conventional parentage allocation tests. Here, we investigate the genetic mating system of the invasive cattle egret using hematophagous insects contained in fake eggs to collect blood from incubating adults in a wild breeding colony. We tested a protocol with a previously unused Neotropical Triatominae, Panstrongylus megistus, obtained blood samples from males and females in 31 nests built on trees, drew blood from 89 nestlings at those nests, and genotyped all samples at 14 microsatellite loci, including six new species-specific loci. We comparatively addressed the performance of parentage allocation versus kinship classification of nestlings to infer the genetic mating system of cattle egrets. In line with previous behavioral observations, we found evidence in support of a non-monogamous genetic mating system, including extra-pair paternity (EPP) and conspecific brood parasitism (CBP). Parentage allocation tests detected a higher percentage of nests with alternative reproductive tactics (EPP: 61.7%; CBP: 64.5%) than the kinship classification method (EPP: 50.0%; CBP: 43.3%). Overall, these results indicate that rates of alternative reproductive tactics inferred in the absence of parental genetic information could be underestimated and should be interpreted with caution. This study highlights the importance of incorporating samples from candidate parents to adequately determine the genetic mating system of a species. We expand knowledge on the reproductive tactics of colonial waterbirds, contributing novel data on the genetic mating system of the cattle egret, valuable for the design of management strategies for this invasive bird.

Fungal genome and mating system transitions facilitated by chromosomal translocations involving intercentromeric recombination

PubMed Central

Yadav, Vikas; Billmyre, R. Blake; Cuomo, Christina A.; Nowrousian, Minou; Wang, Liuyang; Souciet, Jean-Luc; Boekhout, Teun; Porcel, Betina; Wincker, Patrick; Granek, Joshua A.; Sanyal, Kaustuv; Heitman, Joseph

2017-01-01

Species within the human pathogenic Cryptococcus species complex are major threats to public health, causing approximately 1 million annual infections globally. Cryptococcus amylolentus is the most closely known related species of the pathogenic Cryptococcus species complex, and it is non-pathogenic. Additionally, while pathogenic Cryptococcus species have bipolar mating systems with a single large mating type (MAT) locus that represents a derived state in Basidiomycetes, C. amylolentus has a tetrapolar mating system with 2 MAT loci (P/R and HD) located on different chromosomes. Thus, studying C. amylolentus will shed light on the transition from tetrapolar to bipolar mating systems in the pathogenic Cryptococcus species, as well as its possible link with the origin and evolution of pathogenesis. In this study, we sequenced, assembled, and annotated the genomes of 2 C. amylolentus isolates, CBS6039 and CBS6273, which are sexual and interfertile. Genome comparison between the 2 C. amylolentus isolates identified the boundaries and the complete gene contents of the P/R and HD MAT loci. Bioinformatic and chromatin immunoprecipitation sequencing (ChIP-seq) analyses revealed that, similar to those of the pathogenic Cryptococcus species, C. amylolentus has regional centromeres (CENs) that are enriched with species-specific transposable and repetitive DNA elements. Additionally, we found that while neither the P/R nor the HD locus is physically closely linked to its centromere in C. amylolentus, and the regions between the MAT loci and their respective centromeres show overall synteny between the 2 genomes, both MAT loci exhibit genetic linkage to their respective centromere during meiosis, suggesting the presence of recombinational suppressors and/or epistatic gene interactions in the MAT-CEN intervening regions. Furthermore, genomic comparisons between C. amylolentus and related pathogenic Cryptococcus species provide evidence that multiple chromosomal rearrangements mediated by intercentromeric recombination have occurred during descent of the 2 lineages from their common ancestor. Taken together, our findings support a model in which the evolution of the bipolar mating system was initiated by an ectopic recombination event mediated by similar repetitive centromeric DNA elements shared between chromosomes. This translocation brought the P/R and HD loci onto the same chromosome, and further chromosomal rearrangements then resulted in the 2 MAT loci becoming physically linked and eventually fusing to form the single contiguous MAT locus that is now extant in the pathogenic Cryptococcus species. PMID:28800596

Relative Effects of Juvenile and Adult Environmental Factors on Mate Attraction and Recognition in the Cricket, Allonemobius socius

PubMed Central

Olvido, Alexander E.; Fernandes, Pearl R.; Mousseau, Timothy A.

2010-01-01

Finding a mate is a fundamental aspect of sexual reproduction. To this end, specific-mate recognition systems (SMRS) have evolved that facilitate copulation between producers of the mating signal and their opposite-sex responders. Environmental variation, however, may compromise the efficiency with which SMRS operate. In this study, the degree to which seasonal climate experienced during juvenile and adult life-cycle stages affects the SMRS of a cricket, Allonemobius socius (Scudder) (Orthoptera: Gryllidae) was assessed. Results from two-choice behavioral trials suggest that adult ambient temperature, along with population and family origins, mediate variation in male mating call, and to a lesser extent directional response of females for those calls. Restricted maximum-likelihood estimates of heritability for male mating call components and for female response to mating call appeared statistically nonsignificant. However, appreciable “maternal genetic effects” suggest that maternal egg provisioning and other indirect maternal determinants of the embryonic environment significantly contributed to variation in male mating call and female response to mating calls. Thus, environmental factors can generate substantial variation in A. socius mating call, and, more importantly, their marginal effect on female responses to either fast-chirp or long-chirp mating calls suggest negative fitness consequences to males producing alternative types of calls. Future studies of sexual selection and SMRS evolution, particularly those focused on hybrid zone dynamics, should take explicit account of the loose concordance between signal producers and responders suggested by the current findings. PMID:20673114

Genetic determinants of mate recognition in Brachionus manjavacas (Rotifera)

PubMed Central

Snell, Terry W; Shearer, Tonya L; Smith, Hilary A; Kubanek, Julia; Gribble, Kristin E; Welch, David B Mark

2009-01-01

Background Mate choice is of central importance to most animals, influencing population structure, speciation, and ultimately the survival of a species. Mating behavior of male brachionid rotifers is triggered by the product of a chemosensory gene, a glycoprotein on the body surface of females called the mate recognition pheromone. The mate recognition pheromone has been biochemically characterized, but little was known about the gene(s). We describe the isolation and characterization of the mate recognition pheromone gene through protein purification, N-terminal amino acid sequence determination, identification of the mate recognition pheromone gene from a cDNA library, sequencing, and RNAi knockdown to confirm the functional role of the mate recognition pheromone gene in rotifer mating. Results A 29 kD protein capable of eliciting rotifer male circling was isolated by high-performance liquid chromatography. Two transcript types containing the N-terminal sequence were identified in a cDNA library; further characterization by screening a genomic library and by polymerase chain reaction revealed two genes belonging to each type. Each gene begins with a signal peptide region followed by nearly perfect repeats of an 87 to 92 codon motif with no codons between repeats and the final motif prematurely terminated by the stop codon. The two Type A genes contain four and seven repeats and the two Type B genes contain three and five repeats, respectively. Only the Type B gene with three repeats encodes a peptide with a molecular weight of 29 kD. Each repeat of the Type B gene products contains three asparagines as potential sites for N-glycosylation; there are no asparagines in the Type A genes. RNAi with Type A double-stranded RNA did not result in less circling than in the phosphate-buffered saline control, but transfection with Type B double-stranded RNA significantly reduced male circling by 17%. The very low divergence between repeat units, even at synonymous positions, suggests that the repeats are kept nearly identical through a process of concerted evolution. Information-rich molecules like surface glycoproteins are well adapted for chemical communication and aquatic animals may have evolved signaling systems based on these compounds, whereas insects use cuticular hydrocarbons. Conclusion Owing to its critical role in mating, the mate recognition pheromone gene will be a useful molecular marker for exploring the mechanisms and rates of selection and the evolution of reproductive isolation and speciation using rotifers as a model system. The phylogenetic variation in the mate recognition pheromone gene can now be studied in conjunction with the large amount of ecological and population genetic data being gathered for the Brachionus plicatilis species complex to understand better the evolutionary drivers of cryptic speciation. PMID:19740420

Genetic determinants of mate recognition in Brachionus manjavacas (Rotifera).

PubMed

Snell, Terry W; Shearer, Tonya L; Smith, Hilary A; Kubanek, Julia; Gribble, Kristin E; Welch, David B Mark

2009-09-09

Mate choice is of central importance to most animals, influencing population structure, speciation, and ultimately the survival of a species. Mating behavior of male brachionid rotifers is triggered by the product of a chemosensory gene, a glycoprotein on the body surface of females called the mate recognition pheromone. The mate recognition pheromone has been biochemically characterized, but little was known about the gene(s). We describe the isolation and characterization of the mate recognition pheromone gene through protein purification, N-terminal amino acid sequence determination, identification of the mate recognition pheromone gene from a cDNA library, sequencing, and RNAi knockdown to confirm the functional role of the mate recognition pheromone gene in rotifer mating. A 29 kD protein capable of eliciting rotifer male circling was isolated by high-performance liquid chromatography. Two transcript types containing the N-terminal sequence were identified in a cDNA library; further characterization by screening a genomic library and by polymerase chain reaction revealed two genes belonging to each type. Each gene begins with a signal peptide region followed by nearly perfect repeats of an 87 to 92 codon motif with no codons between repeats and the final motif prematurely terminated by the stop codon. The two Type A genes contain four and seven repeats and the two Type B genes contain three and five repeats, respectively. Only the Type B gene with three repeats encodes a peptide with a molecular weight of 29 kD. Each repeat of the Type B gene products contains three asparagines as potential sites for N-glycosylation; there are no asparagines in the Type A genes. RNAi with Type A double-stranded RNA did not result in less circling than in the phosphate-buffered saline control, but transfection with Type B double-stranded RNA significantly reduced male circling by 17%. The very low divergence between repeat units, even at synonymous positions, suggests that the repeats are kept nearly identical through a process of concerted evolution. Information-rich molecules like surface glycoproteins are well adapted for chemical communication and aquatic animals may have evolved signaling systems based on these compounds, whereas insects use cuticular hydrocarbons. Owing to its critical role in mating, the mate recognition pheromone gene will be a useful molecular marker for exploring the mechanisms and rates of selection and the evolution of reproductive isolation and speciation using rotifers as a model system. The phylogenetic variation in the mate recognition pheromone gene can now be studied in conjunction with the large amount of ecological and population genetic data being gathered for the Brachionus plicatilis species complex to understand better the evolutionary drivers of cryptic speciation.

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.

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.

EVOLUTION OF DIVERGENT FEMALE MATING PREFERENCE IN RESPONSE TO EXPERIMENTAL SEXUAL SELECTION

PubMed Central

Debelle, Allan; Ritchie, Michael G; Snook, Rhonda R

2014-01-01

Sexual selection is predicted to drive the coevolution of mating signals and preferences (mating traits) within populations, and could play a role in speciation if sexual isolation arises due to mating trait divergence between populations. However, few studies have demonstrated that differences in mating traits between populations result from sexual selection alone. Experimental evolution is a promising approach to directly examine the action of sexual selection on mating trait divergence among populations. We manipulated the opportunity for sexual selection (low vs. high) in populations of Drosophila pseudoobscura. Previous studies on these experimental populations have shown that sexual selection manipulation resulted in the divergence between sexual selection treatments of several courtship song parameters, including interpulse interval (IPI) which markedly influences male mating success. Here, we measure female preference for IPI using a playback design to test for preference divergence between the sexual selection treatments after 130 generations of experimental sexual selection. The results suggest that female preference has coevolved with male signal, in opposite directions between the sexual selection treatments, providing direct evidence of the ability of sexual selection to drive the divergent coevolution of mating traits between populations. We discuss the implications in the context sexual selection and speciation. PMID:24931497

Heritable determinants of male fertilization success in the nematode Caenorhabditis elegans

PubMed Central

2011-01-01

Background Sperm competition is a driving force in the evolution of male sperm characteristics in many species. In the nematode Caenorhabditis elegans, larger male sperm evolve under experimentally increased sperm competition and larger male sperm outcompete smaller hermaphrodite sperm for fertilization within the hermaphrodite reproductive tract. To further elucidate the relative importance of sperm-related traits that contribute to differential reproductive success among males, we quantified within- and among-strain variation in sperm traits (size, rate of production, number transferred, competitive ability) for seven male genetic backgrounds known previously to differ with respect to some sperm traits. We also quantified male mating ability in assays for rates of courtship and successful copulation, and then assessed the roles of these pre- and post-mating traits in first- and second-male fertilization success. Results We document significant variation in courtship ability, mating ability, sperm size and sperm production rate. Sperm size and production rate were strong indicators of early fertilization success for males that mated second, but male genetic backgrounds conferring faster sperm production make smaller sperm, despite virgin males of all genetic backgrounds transferring indistinguishable numbers of sperm to mating partners. Conclusions We have demonstrated that sperm size and the rate of sperm production represent dominant factors in determining male fertilization success and that C. elegans harbors substantial heritable variation for traits contributing to male reproductive success. C. elegans provides a powerful, tractable system for studying sexual selection and for dissecting the genetic basis and evolution of reproduction-related traits. PMID:21492473

Heritable determinants of male fertilization success in the nematode Caenorhabditis elegans.

PubMed

Murray, Rosalind L; Kozlowska, Joanna L; Cutter, Asher D

2011-04-14

Sperm competition is a driving force in the evolution of male sperm characteristics in many species. In the nematode Caenorhabditis elegans, larger male sperm evolve under experimentally increased sperm competition and larger male sperm outcompete smaller hermaphrodite sperm for fertilization within the hermaphrodite reproductive tract. To further elucidate the relative importance of sperm-related traits that contribute to differential reproductive success among males, we quantified within- and among-strain variation in sperm traits (size, rate of production, number transferred, competitive ability) for seven male genetic backgrounds known previously to differ with respect to some sperm traits. We also quantified male mating ability in assays for rates of courtship and successful copulation, and then assessed the roles of these pre- and post-mating traits in first- and second-male fertilization success. We document significant variation in courtship ability, mating ability, sperm size and sperm production rate. Sperm size and production rate were strong indicators of early fertilization success for males that mated second, but male genetic backgrounds conferring faster sperm production make smaller sperm, despite virgin males of all genetic backgrounds transferring indistinguishable numbers of sperm to mating partners. We have demonstrated that sperm size and the rate of sperm production represent dominant factors in determining male fertilization success and that C. elegans harbors substantial heritable variation for traits contributing to male reproductive success. C. elegans provides a powerful, tractable system for studying sexual selection and for dissecting the genetic basis and evolution of reproduction-related traits.

Effective size of density-dependent two-sex populations: the effect of mating systems.

PubMed

Myhre, A M; Engen, S; SAEther, B-E

2017-08-01

Density dependence in vital rates is a key feature affecting temporal fluctuations of natural populations. This has important implications for the rate of random genetic drift. Mating systems also greatly affect effective population sizes, but knowledge of how mating system and density regulation interact to affect random genetic drift is poor. Using theoretical models and simulations, we compare N e in short-lived, density-dependent animal populations with different mating systems. We study the impact of a fluctuating, density-dependent sex ratio and consider both a stable and a fluctuating environment. We find a negative relationship between annual N e /N and adult population size N due to density dependence, suggesting that loss of genetic variation is reduced at small densities. The magnitude of this decrease was affected by mating system and life history. A male-biased, density-dependent sex ratio reduces the rate of genetic drift compared to an equal, density-independent sex ratio, but a stochastic change towards male bias reduces the N e /N ratio. Environmental stochasticity amplifies temporal fluctuations in population size and is thus vital to consider in estimation of effective population sizes over longer time periods. Our results on the reduced loss of genetic variation at small densities, particularly in polygamous populations, indicate that density regulation may facilitate adaptive evolution at small population sizes. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Experimental evolution reveals trade-offs between mating and immunity.

PubMed

McNamara, Kathryn B; Wedell, Nina; Simmons, Leigh W

2013-08-23

Immune system maintenance and upregulation is costly. Sexual selection intensity, which increases male investment into reproductive traits, is expected to create trade-offs with immune function. We assayed phenoloxidase (PO) and lytic activity of individuals from populations of the Indian meal moth, Plodia interpunctella, which had been evolving under different intensities of sexual selection. We found significant divergence among populations, with males from female-biased populations having lower PO activity than males from balanced sex ratio or male-biased populations. There was no divergence in anti-bacterial lytic activity. Our data suggest that it is the increased male mating demands in female-biased populations that trades-off against immunity, and not the increased investment in sperm transfer per mating that characterizes male-biased populations.

Experimental evolution reveals trade-offs between mating and immunity

PubMed Central

McNamara, Kathryn B.; Wedell, Nina; Simmons, Leigh W.

2013-01-01

Immune system maintenance and upregulation is costly. Sexual selection intensity, which increases male investment into reproductive traits, is expected to create trade-offs with immune function. We assayed phenoloxidase (PO) and lytic activity of individuals from populations of the Indian meal moth, Plodia interpunctella, which had been evolving under different intensities of sexual selection. We found significant divergence among populations, with males from female-biased populations having lower PO activity than males from balanced sex ratio or male-biased populations. There was no divergence in anti-bacterial lytic activity. Our data suggest that it is the increased male mating demands in female-biased populations that trades-off against immunity, and not the increased investment in sperm transfer per mating that characterizes male-biased populations. PMID:23720521

Intrasexual competition facilitates the evolution of alternative mating strategies in a colour polymorphic fish.

PubMed

Hurtado-Gonzales, Jorge L; Uy, J Albert C

2010-12-23

Intense competition for access to females can lead to males exploiting different components of sexual selection, and result in the evolution of alternative mating strategies (AMSs). Males of Poecilia parae, a colour polymorphic fish, exhibit five distinct phenotypes: drab-coloured (immaculata), striped (parae), structural-coloured (blue) and carotenoid-based red and yellow morphs. Previous work indicates that immaculata males employ a sneaker strategy, whereas the red and yellow morphs exploit female preferences for carotenoid-based colours. Mating strategies favouring the maintenance of the other morphs remain to be determined. Here, we report the role of agonistic male-male interactions in influencing female mating preferences and male mating success, and in facilitating the evolution of AMSs. Our study reveals variation in aggressiveness among P. parae morphs during indirect and direct interactions with sexually receptive females. Two morphs, parae and yellow, use aggression to enhance their mating success (i.e., number of copulations) by 1) directly monopolizing access to females, and 2) modifying female preferences after winning agonistic encounters. Conversely, we found that the success of the drab-coloured immaculata morph, which specializes in a sneak copulation strategy, relies in its ability to circumvent both male aggression and female choice when facing all but yellow males. Strong directional selection is expected to deplete genetic variation, yet many species show striking genetically-based polymorphisms. Most studies evoke frequency dependent selection to explain the persistence of such variation. Consistent with a growing body of evidence, our findings suggest that a complex form of balancing selection may alternatively explain the evolution and maintenance of AMSs in a colour polymorphic fish. In particular, this study demonstrates that intrasexual competition results in phenotypically distinct males exhibiting clear differences in their levels of aggression to exclude potential sexual rivals. By being dominant, the more aggressive males are able to circumvent female mating preferences for attractive males, whereas another male type incorporates subordinate behaviours that allow them to circumvent male aggression and female mating preferences. Together, these and previous results indicate that exploiting different aspects of social interactions may allow males to evolve distinct mating strategies and thus the long term maintenance of polymorphisms within populations.

Assortative Mating: Encounter-Network Topology and the Evolution of Attractiveness

PubMed Central

Dipple, S.; Jia, T.; Caraco, T.; Korniss, G.; Szymanski, B. K.

2017-01-01

We model a social-encounter network where linked nodes match for reproduction in a manner depending probabilistically on each node’s attractiveness. The developed model reveals that increasing either the network’s mean degree or the “choosiness” exercised during pair formation increases the strength of positive assortative mating. That is, we note that attractiveness is correlated among mated nodes. Their total number also increases with mean degree and selectivity during pair formation. By iterating over the model’s mapping of parents onto offspring across generations, we study the evolution of attractiveness. Selection mediated by exclusion from reproduction increases mean attractiveness, but is rapidly balanced by skew in the offspring distribution of highly attractive mated pairs. PMID:28345625

Strong assortative mating between allopatric sticklebacks as a by-product of adaptation to different environments

PubMed Central

Vines, Timothy H; Schluter, Dolph

2005-01-01

Speciation involves the evolution of reproductive isolation between populations. One potentially important mechanism is the evolution of pre- or postzygotic isolation between populations as a by-product of adaptation to different environments. In this paper, we tested for assortative mating between allopatric stickleback populations adapted to different ecological niches. Our experimental design controlled for interpopulation interactions and non-adaptive explanations for assortative mating. We found that prezygotic isolation was surprisingly strong: when given a choice, the majority of matings occurred between individuals from similar environments. Our results indicate that the by-product mechanism is a potent source of reproductive isolation, and likely contributed to the origin of sympatric species of sticklebacks. PMID:16627275

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 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

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.

Evolution of Pre- and Post-Copulatory Traits in Male Drosophila melanogaster as a Correlated Response to Selection for Resistance to Cold Stress

PubMed Central

Singh, Karan; Samant, Manas Arun; Tom, Megha Treesa; Prasad, Nagaraj Guru

2016-01-01

Background In Drosophila melanogaster the fitness of males depends on a broad array of reproductive traits classified as pre- and post-copulatory traits. Exposure to cold stress, can reduce sperm number, male mating ability and courtship behavior. Therefore, it is expected that the adaptation to cold stress will involve changes in pre- and post-copulatory traits. Such evolution of reproductive traits in response to cold stress is not well studied. Methods We selected replicate populations of D. melanogaster for resistance to cold shock. Over 37–46 generations of selection, we investigated pre- and post-copulatory traits such as mating latency, copulation duration, mating frequency, male fertility, fitness (progeny production) and sperm competitive ability in male flies subjected to cold shock and those not subjected to cold shock. Results We found that post cold shock, the males from the selected populations had a significantly lower mating latency along with, higher mating frequency, fertility, sperm competitive ability and number of progeny relative to the control populations. Conclusion While most studies of experimental evolution of cold stress resistance have documented the evolution of survivorship in response to selection, our study clearly shows that adaptation to cold stress involves rapid changes in the pre- and post-copulatory traits. Additionally, improved performances under stressful conditions need not necessarily trade-off with performance under benign conditions. PMID:27093599

Lifetime inbreeding depression, purging, and mating system evolution in a simultaneous hermaphrodite tapeworm.

PubMed

Benesh, Daniel P; Weinreich, Friederike; Kalbe, Martin; Milinski, Manfred

2014-06-01

Classical theory on mating system evolution suggests that simultaneous hermaphrodites should either outcross if they have high inbreeding depression (ID) or self-fertilize if they have low ID. However, a mixture of selfing and outcrossing persists in many species. Previous studies with the tapeworm Schistocephalus solidus have found worms to self-fertilize some of their eggs despite ID. The probability for selfing to spread depends on the relative fitness of selfers, as well as the genetic basis for ID and whether it can be effectively purged. We bred S. solidus through two consecutive generations of selfing and recorded several fitness correlates over the whole life cycle. After one round of selfing, ID was pronounced, particularly in early-life traits, and the conservatively estimated lifetime fitness of selfed progeny was only 9% that of the outcrossed controls. After a second generation of selfing, ID remained high but was significantly reduced in several traits, which is consistent with the purging of deleterious recessive alleles (the estimated load of lethal equivalents dropped by 48%). Severe ID, even if it can be rapidly purged, likely prevents transitions toward pure selfing in this parasite, although we also cannot exclude the possibility that low-level selfing has undetected benefits. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Does paedomorphosis contribute to prairie vole monogamy?

PubMed Central

Bushyhead, Timothy; Curtis, J. Thomas

2015-01-01

We examined skull morphology in prairie voles (Microtus ochrogaster) and meadow voles (M. pennsylvanicus), two closely related species with fundamentally different mating systems, to test the hypothesis that paedomorphosis contributes to the evolution of monogamous mating systems. Using several skull measurements, we found that the overall length:width ratio of meadow vole skulls was greater than that of prairie voles suggesting that meadow vole have longer narrower skulls. We then examined which aspects of skull morphology differed between the species and found that the ratio difference was attributable primarily to longer snout length in meadow voles. Finally, we compared adult morphology in both species to that of pups and found the prairie vole, a monogamous species, displays a more juvenile-like skull morphology than does the meadow vole, a promiscuous species. These results suggest that monogamous vole species retain more juvenile-like morphology than do promiscuous species, and thus possibly retain juvenile-like behaviors that may contribute to a monogamous mating system. PMID:26594100

Does paedomorphosis contribute to prairie vole monogamy?

PubMed

Bushyhead, Timothy; Curtis, J Thomas

We examined skull morphology in prairie voles ( Microtus ochrogaster ) and meadow voles ( M. pennsylvanicus ), two closely related species with fundamentally different mating systems, to test the hypothesis that paedomorphosis contributes to the evolution of monogamous mating systems. Using several skull measurements, we found that the overall length:width ratio of meadow vole skulls was greater than that of prairie voles suggesting that meadow vole have longer narrower skulls. We then examined which aspects of skull morphology differed between the species and found that the ratio difference was attributable primarily to longer snout length in meadow voles. Finally, we compared adult morphology in both species to that of pups and found the prairie vole, a monogamous species, displays a more juvenile-like skull morphology than does the meadow vole, a promiscuous species. These results suggest that monogamous vole species retain more juvenile-like morphology than do promiscuous species, and thus possibly retain juvenile-like behaviors that may contribute to a monogamous mating system.

All Features Great and Small-the Potential Roles of the Baculum and Penile Spines in Mammals.

PubMed

Orr, Teri J; Brennan, Patricia L R

2016-10-01

Mammalian penises are morphologically diverse, including a highly variable and taxonomically informative baculum (os penis), and variable penile spines, both of which are possessed by many-but not all-species. To understand the evolution of genital morphologies, as well as the potential role of both the baculum, and penile spines that directly interact with female reproductive tract, we undertook a comparative study of male penile spines and their relationship with the baculum across all mammalian orders. Specifically, we investigated several factors that may explain the presence or absence of penile spines in mammals, including mating system, risk of sperm competition, female reproductive physiology, presence and width of the baculum, and phylogenetic history. We observed that the presence of both the baculum and penile spines is correlated with residual testes size, suggesting a potential role in sexual selection for these traits. We found no association between the presence of spines and mating system, or with the presence/width of the baculum, although relative testes mass was marginally associated with baculum width. We found no relationship between baculum presence or width and mating system. We also noted that spines presence or absence have an order-level distribution, and clear phylogenetic patterns of distribution across mammals. It is likely that spine morphology and distribution, not just presence, play an important role in genital evolution in mammals, but these features are poorly described in most groups. Quantitative data collection in most mammalian taxa would be useful to further elucidate the evolution of the complex genital morphology of this group. © The Author 2016. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Evolution of Inbreeding Avoidance and Inbreeding Preference through Mate Choice among Interacting Relatives.

PubMed

Duthie, A Bradley; Reid, Jane M

2016-12-01

While extensive population genetic theory predicts conditions favoring evolution of self-fertilization versus outcrossing, there is no analogous theory that predicts conditions favoring evolution of inbreeding avoidance or inbreeding preference enacted through mate choice given obligate biparental reproduction. Multiple interacting processes complicate the dynamics of alleles underlying such inbreeding strategies, including sexual conflict, distributions of kinship, genetic drift, purging of mutation load, direct costs, and restricted kin discrimination. We incorporated these processes into an individual-based model to predict conditions where selection should increase or decrease frequencies of alleles causing inbreeding avoidance or inbreeding preference when females or males controlled mating. Selection for inbreeding avoidance occurred given strong inbreeding depression when either sex chose mates, while selection for inbreeding preference occurred given very weak inbreeding depression when females chose but never occurred when males chose. Selection for both strategies was constrained by direct costs and restricted kin discrimination. Purging was negligible, but allele frequencies were strongly affected by drift in small populations, while selection for inbreeding avoidance was weak in larger populations because inbreeding risk decreased. Therefore, while selection sometimes favored alleles underlying inbreeding avoidance or preference, evolution of such strategies may be much more restricted and stochastic than is commonly presumed.

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

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).

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

Differentiating the evolution of female song and male-female duets in the New World blackbirds: can tropical natural history traits explain duet evolution?

PubMed

Odom, Karan J; Omland, Kevin E; Price, J Jordan

2015-03-01

Female bird song and combined vocal duets of mated pairs are both frequently associated with tropical, monogamous, sedentary natural histories. Little is known, however, about what selects for duetting behavior versus female song. Female song likely preceded duet evolution and could drive apparent relationships between duets and these natural histories. We compared the evolution of female song and male-female duets in the New World blackbirds (Icteridae) by investigating patterns of gains and losses of both traits and their relationships with breeding latitude, mating system, nesting pattern, and migratory behavior. We found that duets evolved only in lineages in which female song was likely ancestral. Both female song and duets were correlated with tropical breeding, social monogamy, territorial nesting, and sedentary behavior when all taxa were included; however, correlations between duets and these natural history traits disappeared when comparisons were limited to taxa with female song. Also, likelihood values supported stronger relationships between the natural history traits and female song than between these traits and duets. Our results suggest that the natural histories thought to favor the evolution of duetting may in fact be associated with female song and that additional selection pressures are responsible for the evolution of duets. © 2015 The Author(s).

Resistance evolution to Bt crops: predispersal mating of European corn borers.

PubMed

Dalecky, Ambroise; Ponsard, Sergine; Bailey, Richard I; Pélissier, Céline; Bourguet, Denis

2006-06-01

Over the past decade, the high-dose refuge (HDR) strategy, aimed at delaying the evolution of pest resistance to Bacillus thuringiensis (Bt) toxins produced by transgenic crops, became mandatory in the United States and is being discussed for Europe. However, precopulatory dispersal and the mating rate between resident and immigrant individuals, two features influencing the efficiency of this strategy, have seldom been quantified in pests targeted by these toxins. We combined mark-recapture and biogeochemical marking over three breeding seasons to quantify these features directly in natural populations of Ostrinia nubilalis, a major lepidopteran corn pest. At the local scale, resident females mated regardless of males having dispersed beforehand or not, as assumed in the HDR strategy. Accordingly, 0-67% of resident females mating before dispersal did so with resident males, this percentage depending on the local proportion of resident males (0% to 67.2%). However, resident males rarely mated with immigrant females (which mostly arrived mated), the fraction of females mating before dispersal was variable and sometimes substantial (4.8% to 56.8%), and there was no evidence for male premating dispersal being higher. Hence, O. nubilalis probably mates at a more restricted spatial scale than previously assumed, a feature that may decrease the efficiency of the HDR strategy under certain circumstances, depending for example on crop rotation practices.

The scope and strength of sex-specific selection in genome evolution.

PubMed

Wright, A E; Mank, J E

2013-09-01

Males and females share the vast majority of their genomes and yet are often subject to different, even conflicting, selection. Genomic and transcriptomic developments have made it possible to assess sex-specific selection at the molecular level, and it is clear that sex-specific selection shapes the evolutionary properties of several genomic characteristics, including transcription, post-transcriptional regulation, imprinting, genome structure and gene sequence. Sex-specific selection is strongly influenced by mating system, which also causes neutral evolutionary changes that affect different regions of the genome in different ways. Here, we synthesize theoretical and molecular work in order to provide a cohesive view of the role of sex-specific selection and mating system in genome evolution. We also highlight the need for a combined approach, incorporating both genomic data and experimental phenotypic studies, in order to understand precisely how sex-specific selection drives evolutionary change across the genome. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

Experimental evolution of a sexually selected display in yeast

PubMed Central

Rogers, David W.; Greig, Duncan

2008-01-01

The fundamental principle underlying sexual selection theory is that an allele conferring an advantage in the competition for mates will spread through a population. Remarkably, this has never been demonstrated empirically. We have developed an experimental system using yeast for testing genetic models of sexual selection. Yeast signal to potential partners by producing an attractive pheromone; stronger signallers are preferred as mates. We tested the effect of high and low levels of sexual selection on the evolution of a gene determining the strength of this signal. Under high sexual selection, an allele encoding a stronger signal was able to invade a population of weak signallers, and we observed a corresponding increase in the amount of pheromone produced. By contrast, the strong signalling allele failed to invade under low sexual selection. Our results demonstrate, for the first time, the spread of a sexually selected allele through a population, confirming the central assumption of sexual selection theory. Our yeast system is a powerful tool for investigating the genetics of sexual selection. PMID:18842545

The evolution of sex roles in birds is related to adult sex ratio.

PubMed

Liker, András; Freckleton, Robert P; Székely, Tamás

2013-01-01

Sex-role reversal represents a formidable challenge for evolutionary biologists, since it is not clear which ecological, life-history or social factors facilitated conventional sex roles (female care and male-male competition for mates) to be reversed (male care and female-female competition). Classic theories suggested ecological or life-history predictors of role reversal, but most studies failed to support these hypotheses. Recent theory however predicts that sex-role reversal should be driven by male-biased adult sex ratio (ASR). Here we test this prediction for the first time using phylogenetic comparative analyses. Consistent with theory, both mating system and parental care are strongly related to ASR in shorebirds: conventional sex roles are exhibited by species with female-biased ASR, whereas sex-role reversal is associated with male-biased ASR. These results suggest that social environment has a strong influence on breeding systems and therefore revealing the causes of ASR variation in wild populations is essential for understanding sex role evolution.

Genetic quality and sexual selection: an integrated framework for good genes and compatible genes.

PubMed

Neff, Bryan D; Pitcher, Trevor E

2005-01-01

Why are females so choosy when it comes to mating? This question has puzzled and marveled evolutionary and behavioral ecologists for decades. In mating systems in which males provide direct benefits to the female or her offspring, such as food or shelter, the answer seems straightforward--females should prefer to mate with males that are able to provide more resources. The answer is less clear in other mating systems in which males provide no resources (other than sperm) to females. Theoretical models that account for the evolution of mate choice in such nonresource-based mating systems require that females obtain a genetic benefit through increased offspring fitness from their choice. Empirical studies of nonresource-based mating systems that are characterized by strong female choice for males with elaborate sexual traits (like the large tail of peacocks) suggest that additive genetic benefits can explain only a small percentage of the variation in fitness. Other research on genetic benefits has examined nonadditive effects as another source of genetic variation in fitness and a potential benefit to female mate choice. In this paper, we review the sexual selection literature on genetic quality to address five objectives. First, we attempt to provide an integrated framework for discussing genetic quality. We propose that the term 'good gene' be used exclusively to refer to additive genetic variation in fitness, 'compatible gene' be used to refer to nonadditive genetic variation in fitness, and 'genetic quality' be defined as the sum of the two effects. Second, we review empirical approaches used to calculate the effect size of genetic quality and discuss these approaches in the context of measuring benefits from good genes, compatible genes and both types of genes. Third, we discuss biological mechanisms for acquiring and promoting offspring genetic quality and categorize these into three stages during breeding: (i) precopulatory (mate choice); (ii) postcopulatory, prefertilization (sperm utilization); and (iii) postcopulatory, postfertilization (differential investment). Fourth, we present a verbal model of the effect of good genes sexual selection and compatible genes sexual selection on population genetic variation in fitness, and discuss the potential trade-offs that might exist between mate choice for good genes and mate choice for compatible genes. Fifth, we discuss some future directions for research on genetic quality and sexual selection.

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.

Monogamy and haplodiploidy act in synergy to promote the evolution of eusociality.

PubMed

Fromhage, Lutz; Kokko, Hanna

2011-07-19

In eusocial species, some individuals sacrifice their own reproduction for the benefit of others. The evolutionary transition towards eusociality may have been facilitated by ancestral species having a monogamous mating system (the monogamy hypothesis) or a haplodiploid genetic system (the haplodiploidy hypothesis), or it may have been entirely driven by other (ecological) factors. Here we show, using a model that describes the dynamics of insect colony foundation, growth and death, that monogamy and haplodiploidy facilitate the evolution of eusociality in a novel, mutually reinforcing way. Our findings support the recently questioned importance of relatedness for the evolution of eusociality, and simultaneously highlight the importance of explicitly accounting for the ecological rules of colony foundation, growth and death in models of social 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.

Olfactory eavesdropping by a competitively foraging stingless bee, Trigona spinipes.

PubMed Central

Nieh, James C.; Barreto, Lillian S.; Contrera, Felipe A. L.; Imperatriz-Fonseca, Vera L.

2004-01-01

Signals that are perceived over long distances or leave extended spatial traces are subject to eavesdropping. Eavesdropping has therefore acted as a selective pressure in the evolution of diverse animal communication systems, perhaps even in the evolution of functionally referential communication. Early work suggested that some species of stingless bees (Hymenoptera, Apidae, Meliponini) may use interceptive olfactory eavesdropping to discover food sources being exploited by competitors, but it is not clear if any stingless bee can be attracted to the odour marks deposited by an interspecific competitor. We show that foragers of the aggressive meliponine bee, Trigona spinipes, can detect and orient towards odour marks deposited by a competitor, Melipona rufiventris, and then rapidly take over the food source, driving away or killing their competitors. When searching for food sources at new locations that they are not already exploiting, T. spinipes foragers strongly prefer M. rufiventris odour marks to odour marks deposited by their own nest-mates, whereas they prefer nest-mate odour marks over M. rufiventris odour marks at a location already occupied by T. spinipes nest-mates. Melipona rufiventris foragers flee from T. spinipes odour marks. This olfactory eavesdropping may have played a role in the evolution of potentially cryptic communication mechanisms such as shortened odour trails, point-source only odour marking and functionally referential communication concealed at the nest. PMID:15306311

Interspecific Sex in Grass Smuts and the Genetic Diversity of Their Pheromone-Receptor System

PubMed Central

Kellner, Ronny; Vollmeister, Evelyn; Feldbrügge, Michael; Begerow, Dominik

2011-01-01

The grass smuts comprise a speciose group of biotrophic plant parasites, so-called Ustilaginaceae, which are specifically adapted to hosts of sweet grasses, the Poaceae family. Mating takes a central role in their life cycle, as it initiates parasitism by a morphological and physiological transition from saprobic yeast cells to pathogenic filaments. As in other fungi, sexual identity is determined by specific genomic regions encoding allelic variants of a pheromone-receptor (PR) system and heterodimerising transcription factors. Both operate in a biphasic mating process that starts with PR–triggered recognition, directed growth of conjugation hyphae, and plasmogamy of compatible mating partners. So far, studies on the PR system of grass smuts revealed diverse interspecific compatibility and mating type determination. However, many questions concerning the specificity and evolutionary origin of the PR system remain unanswered. Combining comparative genetics and biological approaches, we report on the specificity of the PR system and its genetic diversity in 10 species spanning about 100 million years of mating type evolution. We show that three highly syntenic PR alleles are prevalent among members of the Ustilaginaceae, favouring a triallelic determination as the plesiomorphic characteristic of this group. Furthermore, the analysis of PR loci revealed increased genetic diversity of single PR locus genes compared to genes of flanking regions. Performing interspecies sex tests, we detected a high potential for hybridisation that is directly linked to pheromone signalling as known from intraspecies sex. Although the PR system seems to be optimised for intraspecific compatibility, the observed functional plasticity of the PR system increases the potential for interspecific sex, which might allow the hybrid-based genesis of newly combined host specificities. PMID:22242007

Banded mongooses avoid inbreeding when mating with members of the same natal group.

PubMed

Sanderson, Jennifer L; Wang, Jinliang; Vitikainen, Emma I K; Cant, Michael A; Nichols, Hazel J

2015-07-01

Inbreeding and inbreeding avoidance are key factors in the evolution of animal societies, influencing dispersal and reproductive strategies which can affect relatedness structure and helping behaviours. In cooperative breeding systems, individuals typically avoid inbreeding through reproductive restraint and/or dispersing to breed outside their natal group. However, where groups contain multiple potential mates of varying relatedness, strategies of kin recognition and mate choice may be favoured. Here, we investigate male mate choice and female control of paternity in the banded mongoose (Mungos mungo), a cooperatively breeding mammal where both sexes are often philopatric and mating between relatives is known to occur. We find evidence suggestive of inbreeding depression in banded mongooses, indicating a benefit to avoiding breeding with relatives. Successfully breeding pairs were less related than expected under random mating, which appeared to be driven by both male choice and female control of paternity. Male banded mongooses actively guard females to gain access to mating opportunities, and this guarding behaviour is preferentially directed towards less closely related females. Guard-female relatedness did not affect the guard's probability of gaining reproductive success. However, where mate-guards are unsuccessful, they lose paternity to males that are less related to the females than themselves. Together, our results suggest that both sexes of banded mongoose use kin discrimination to avoid inbreeding. Although this strategy appears to be rare among cooperative breeders, it may be more prominent in species where relatedness to potential mates is variable, and/or where opportunities for dispersal and mating outside of the group are limited. © 2015 John Wiley & Sons Ltd.

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.

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

Genetic architecture and evolution of the mating type locus in fusaria that cause soybean sudden death syndrome and bean root rot

USDA-ARS?s Scientific Manuscript database

Fusarium tucumaniae is the only known sexually reproducing species among the seven closely related fusaria that cause soybean sudden death syndrome (SDS) or bean root rot (BRR). Laboratory mating of F. tucumaniae required two mating-compatible strains, indicating that it is heterothallic. To assess ...

Direct detection of male quality can facilitate the evolution of female choosiness and indicators of good genes: Evolution across a continuum of indicator mechanisms.

PubMed

Dhole, Sumit; Stern, Caitlin A; Servedio, Maria R

2018-04-01

The evolution of mating displays as indicators of male quality has been the subject of extensive theoretical and empirical research for over four decades. Research has also addressed the evolution of female mate choice favoring such indicators. Yet, much debate still exists about whether displays can evolve through the indirect benefits of female mate choice. Here, we use a population genetic model to investigate how the extent to which females can directly detect male quality influences the evolution of female choosiness and male displays. We use a continuum framework that incorporates indicator mechanisms that are traditionally modeled separately. Counter to intuition, we find that intermediate levels of direct detection of male quality can facilitate, rather than impede, the evolution of female choosiness and male displays in broad regions of this continuum. We examine how this evolution is driven by selective forces on genetic quality and on the display, and find that direct detection of male quality results in stronger indirect selection favoring female choosiness. Our results imply that displays maybe more likely to evolve when female choosiness has already evolved to discriminate perceptible forms of male quality. They also highlight the importance of considering general female choosiness, as well as preference, in studies of "good genes." © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Behavioural divergence, interfertility and speciation: a review.

PubMed

Pillay, Neville; Rymer, Tasmin L

2012-11-01

Behavioural compatibility between mates is fundamental for maintaining species boundaries and is achieved through appropriate communication between males and females. A breakdown in communication will lead to behavioural divergence and reduced interfertility. In this review, we summarise the current knowledge on male signals and female perception of these signals, integrating the literature from several taxa. We advocate that signaller-perceiver coevolution, which is usually under strong stabilising selection to enable mating, forms the basis of species-specific mate recognition systems. The mechanisms (phylogeny, geography, ecology, biology) shaping signaller-perceiver systems are briefly discussed to demonstrate the factors underpinning the evolution of signaller-perceiver couplings. Since divergence and diversification of communication systems is driven by changes in the mechanical properties of sensory pathways and morphology of sensory organs, we highlight signal modalities (auditory, olfactory, visual, tactile) and their importance in communication, particularly in mate selection. Next, using available examples and generating a stylised model, we suggest how disruption (biological, ecological, stochastic) of signaller-perceiver systems drives behavioural divergence and consequently results in reduced interfertility and speciation. Future studies should adopt an integrative approach, combining multiple parameters (phylogeny, adaptive utility of communication systems, genetics and biomechanical/biochemical properties of signals and perception) to explore how disruption of signaller-perceiver systems results in behavioural divergence and reduced interfertility. Finally, we question the impact that rapid environmental change will have on disruption of communication systems, potentially interfering with signaller-perceiver couplings. Copyright © 2012 Elsevier B.V. All rights reserved.

Are sex ratio distorting endosymbionts responsible for mating system variation among dance flies (Diptera: Empidinae)?

PubMed Central

Herridge, Elizabeth J.; Ness, Rob W.; Bussière, Luc F.

2017-01-01

Maternally inherited bacterial endosymbionts are common in many arthropod species. Some endosymbionts cause female-biased sex ratio distortion in their hosts that can result in profound changes to a host’s mating behaviour and reproductive biology. Dance flies (Diptera: Empidinae) are well known for their unusual reproductive biology, including species with female-specific ornamentation and female-biased lek-like swarming behaviour. The cause of the repeated evolution of female ornaments in these flies remains unknown, but is probably associated with female-biased sex ratios in individual species. In this study we assessed whether dance flies harbour sex ratio distorting endosymbionts that might have driven these mating system evolutionary changes. We measured the incidence and prevalence of infection by three endosymbionts that are known to cause female-biased sex ratios in other insect hosts (Wolbachia, Rickettsia and Spiroplasma) across 20 species of dance flies. We found evidence of widespread infection by all three symbionts and variation in sex-specific prevalence across the taxa sampled. However, there was no relationship between infection prevalence and adult sex ratio measures and no evidence that female ornaments are associated with high prevalences of sex-biased symbiont infections. We conclude that the current distribution of endosymbiont infections is unlikely to explain the diversity in mating systems among dance fly species. PMID:28609446

Are sex ratio distorting endosymbionts responsible for mating system variation among dance flies (Diptera: Empidinae)?

PubMed

Murray, Rosalind L; Herridge, Elizabeth J; Ness, Rob W; Bussière, Luc F

2017-01-01

Maternally inherited bacterial endosymbionts are common in many arthropod species. Some endosymbionts cause female-biased sex ratio distortion in their hosts that can result in profound changes to a host's mating behaviour and reproductive biology. Dance flies (Diptera: Empidinae) are well known for their unusual reproductive biology, including species with female-specific ornamentation and female-biased lek-like swarming behaviour. The cause of the repeated evolution of female ornaments in these flies remains unknown, but is probably associated with female-biased sex ratios in individual species. In this study we assessed whether dance flies harbour sex ratio distorting endosymbionts that might have driven these mating system evolutionary changes. We measured the incidence and prevalence of infection by three endosymbionts that are known to cause female-biased sex ratios in other insect hosts (Wolbachia, Rickettsia and Spiroplasma) across 20 species of dance flies. We found evidence of widespread infection by all three symbionts and variation in sex-specific prevalence across the taxa sampled. However, there was no relationship between infection prevalence and adult sex ratio measures and no evidence that female ornaments are associated with high prevalences of sex-biased symbiont infections. We conclude that the current distribution of endosymbiont infections is unlikely to explain the diversity in mating systems among dance fly species.

Polyandrous females provide sons with more competitive sperm: Support for the sexy-sperm hypothesis in the rattlebox moth (Utetheisa ornatrix).

PubMed

Egan, Andrea L; Hook, Kristin A; Reeve, H Kern; Iyengar, Vikram K

2016-01-01

Given the costs of multiple mating, why has female polyandry evolved? Utetheisa ornatrix moths are well suited for studying multiple mating in females because females are highly polyandrous over their life span, with each male mate transferring a substantial spermatophore with both genetic and nongenetic material. The accumulation of resources might explain the prevalence of polyandry in this species, but another, not mutually exclusive, possibility is that females mate multiply to increase the probability that their sons will inherit more-competitive sperm. This latter "sexy-sperm" hypothesis posits that female multiple mating and male sperm competitiveness coevolve via a Fisherian runaway process. We tested the sexy-sperm hypothesis by using competitive double matings to compare the sperm competition success of sons of polyandrous versus monandrous females. In accordance with sexy-sperm theory, we found that in 511 offspring across 17 families, the male whose polyandrous mother mated once with each of three different males sired significantly more of all total offspring (81%) than did the male whose monandrous mother was mated thrice to a single male. Interestingly, sons of polyandrous mothers had a significantly biased sex ratio of their brood toward sons, also in support of the hypothesis. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

The evolution of female ornaments and weaponry: social selection, sexual selection and ecological competition

PubMed Central

Tobias, Joseph A.; Montgomerie, Robert; Lyon, Bruce E.

2012-01-01

Ornaments, weapons and aggressive behaviours may evolve in female animals by mate choice and intrasexual competition for mating opportunities—the standard forms of sexual selection in males. However, a growing body of evidence suggests that selection tends to operate in different ways in males and females, with female traits more often mediating competition for ecological resources, rather than mate acquisition. Two main solutions have been proposed to accommodate this disparity. One is to expand the concept of sexual selection to include all mechanisms related to fecundity; another is to adopt an alternative conceptual framework—the theory of social selection—in which sexual selection is one component of a more general form of selection resulting from all social interactions. In this study, we summarize the history of the debate about female ornaments and weapons, and discuss potential resolutions. We review the components of fitness driving ornamentation in a wide range of systems, and show that selection often falls outside the limits of traditional sexual selection theory, particularly in females. We conclude that the evolution of these traits in both sexes is best understood within the unifying framework of social selection. PMID:22777016

The evolution of female ornaments and weaponry: social selection, sexual selection and ecological competition.

PubMed

Tobias, Joseph A; Montgomerie, Robert; Lyon, Bruce E

2012-08-19

Ornaments, weapons and aggressive behaviours may evolve in female animals by mate choice and intrasexual competition for mating opportunities-the standard forms of sexual selection in males. However, a growing body of evidence suggests that selection tends to operate in different ways in males and females, with female traits more often mediating competition for ecological resources, rather than mate acquisition. Two main solutions have been proposed to accommodate this disparity. One is to expand the concept of sexual selection to include all mechanisms related to fecundity; another is to adopt an alternative conceptual framework-the theory of social selection-in which sexual selection is one component of a more general form of selection resulting from all social interactions. In this study, we summarize the history of the debate about female ornaments and weapons, and discuss potential resolutions. We review the components of fitness driving ornamentation in a wide range of systems, and show that selection often falls outside the limits of traditional sexual selection theory, particularly in females. We conclude that the evolution of these traits in both sexes is best understood within the unifying framework of social selection.

How sexual selection can drive the evolution of costly sperm ornamentation

NASA Astrophysics Data System (ADS)

Lüpold, Stefan; Manier, Mollie K.; Puniamoorthy, Nalini; Schoff, Christopher; Starmer, William T.; Luepold, Shannon H. Buckley; Belote, John M.; Pitnick, Scott

2016-05-01

Post-copulatory sexual selection (PSS), fuelled by female promiscuity, is credited with the rapid evolution of sperm quality traits across diverse taxa. Yet, our understanding of the adaptive significance of sperm ornaments and the cryptic female preferences driving their evolution is extremely limited. Here we review the evolutionary allometry of exaggerated sexual traits (for example, antlers, horns, tail feathers, mandibles and dewlaps), show that the giant sperm of some Drosophila species are possibly the most extreme ornaments in all of nature and demonstrate how their existence challenges theories explaining the intensity of sexual selection, mating-system evolution and the fundamental nature of sex differences. We also combine quantitative genetic analyses of interacting sex-specific traits in D. melanogaster with comparative analyses of the condition dependence of male and female reproductive potential across species with varying ornament size to reveal complex dynamics that may underlie sperm-length evolution. Our results suggest that producing few gigantic sperm evolved by (1) Fisherian runaway selection mediated by genetic correlations between sperm length, the female preference for long sperm and female mating frequency, and (2) longer sperm increasing the indirect benefits to females. Our results also suggest that the developmental integration of sperm quality and quantity renders post-copulatory sexual selection on ejaculates unlikely to treat male-male competition and female choice as discrete processes.

Sexy sons from re-mating do not recoup the direct costs of harmful male interactions in the Drosophila melanogaster laboratory model system.

PubMed

Orteiza, N; Linder, J E; Rice, W R

2005-09-01

The empirical foundation for sexual conflict theory is the data from many different taxa demonstrating that females are harmed while interacting with males. However, the interpretation of this keystone evidence has been challenged because females may more than counterbalance the direct costs of interacting with males by the indirect benefits of obtaining higher quality genes for their offspring. A quantification of this trade-off is critical to resolve the controversy and is presented here. A multi-generation fitness assay in the Drosophila melanogaster laboratory model system was used to quantify both the direct costs to females due to interactions with males and indirect benefits via sexy sons. We specifically focus on the interactions that occur between males and nonvirgin females. In the laboratory environment of our base population, females mate soon after eclosion and store sufficient sperm for their entire lifetime, yet males persistently court these nonvirgin females and frequently succeed in re-mating them. Females may benefit from these interactions despite direct costs to their lifetime fecundity if re-mating allows them to trade-up to mates of higher genetic quality and thereby secure indirect benefits for their offspring. We found that direct costs of interactions between males and nonvirgin females substantially exceeded indirect benefits through sexy sons. These data, in combination with past studies of the good genes route of indirect benefits, demonstrate that inter-sexual interactions drive sexually antagonistic co-evolution in this model system.

Sexual selection accelerates signal evolution during speciation in birds.

PubMed

Seddon, Nathalie; Botero, Carlos A; Tobias, Joseph A; Dunn, Peter O; Macgregor, Hannah E A; Rubenstein, Dustin R; Uy, J Albert C; Weir, Jason T; Whittingham, Linda A; Safran, Rebecca J

2013-09-07

Sexual selection is proposed to be an important driver of diversification in animal systems, yet previous tests of this hypothesis have produced mixed results and the mechanisms involved remain unclear. Here, we use a novel phylogenetic approach to assess the influence of sexual selection on patterns of evolutionary change during 84 recent speciation events across 23 passerine bird families. We show that elevated levels of sexual selection are associated with more rapid phenotypic divergence between related lineages, and that this effect is restricted to male plumage traits proposed to function in mate choice and species recognition. Conversely, we found no evidence that sexual selection promoted divergence in female plumage traits, or in male traits related to foraging and locomotion. These results provide strong evidence that female choice and male-male competition are dominant mechanisms driving divergence during speciation in birds, potentially linking sexual selection to the accelerated evolution of pre-mating reproductive isolation.

Changes of sex pheromone communication systems associated with tebufenozide and abamectin resistance in diamondback moth, Plutella xylostella (L.).

PubMed

Xu, Zhen; Cao, Guang-Chun; Dong, Shuang-Lin

2010-05-01

Many insect pests have evolved resistance to insecticides. Along with this evolution, the sex pheromone communication system of insects also may change, and subsequently reproductive isolation may occur between resistant and susceptible populations. In this study of the diamondback moth, we found that resistant females (especially Abamectin resistant females) produced less sex pheromone and displayed a lower level of calling behavior. Resistant males showed higher EAG responsiveness to the sex pheromone mixture of females, and responded to a broader range of ratios between the two major components compared to the responses of susceptible moths. In addition, wind tunnel experiments indicated that changes associated with insecticide resistance in the Abamectin resistant strain (Aba-R) significantly reduced female attractiveness to susceptible males. Furthermore, mating choice experiments confirmed that non-random mating occurred between the two different strains. Aba-R females with an abnormal pheromone production and blend ratio exhibited significantly lower mating percentages with males from either their own strain or other strains, which corroborates the results obtained by the wind tunnel experiments. The implications of this non-random mating for insect speciation and insecticide resistance management are discussed.

Beyond promiscuity: mate-choice commitments in social breeding

PubMed Central

Boomsma, Jacobus J.

2013-01-01

Obligate eusociality with distinct caste phenotypes has evolved from strictly monogamous sub-social ancestors in ants, some bees, some wasps and some termites. This implies that no lineage reached the most advanced form of social breeding, unless helpers at the nest gained indirect fitness values via siblings that were identical to direct fitness via offspring. The complete lack of re-mating promiscuity equalizes sex-specific variances in reproductive success. Later, evolutionary developments towards multiple queen-mating retained lifetime commitment between sexual partners, but reduced male variance in reproductive success relative to female's, similar to the most advanced vertebrate cooperative breeders. Here, I (i) discuss some of the unique and highly peculiar mating system adaptations of eusocial insects; (ii) address ambiguities that remained after earlier reviews and extend the monogamy logic to the evolution of soldier castes; (iii) evaluate the evidence for indirect fitness benefits driving the dynamics of (in)vertebrate cooperative breeding, while emphasizing the fundamental differences between obligate eusociality and cooperative breeding; (iv) infer that lifetime commitment is a major driver towards higher levels of organization in bodies, colonies and mutualisms. I argue that evolutionary informative definitions of social systems that separate direct and indirect fitness benefits facilitate transparency when testing inclusive fitness theory. PMID:23339241

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.

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.

Evolution of mating system and the genetic covariance between male and female investment in Clarkia (onagraceae): selfing opposes the evolution of trade-offs.

PubMed

Mazer, Susan J; Delesalle, Véronique A; Paz, Horacio

2007-01-01

Sex allocation theory has assumed that hermaphroditic species exhibit strong genetically based trade-offs between investment in male and female function. The potential effects of mating system on the evolution of this genetic covariance, however, have not been explored. We have challenged the assumption of a ubiquitous trade-off between male and female investment by arguing that in highly self-fertilizing species, stabilizing natural selection should favor highly efficient ratios of male to female gametes. In flowering plants, the result of such selection would be similar pollen:ovule (P:O) ratios across selfing genotypes, precluding a negative genetic correlation (r(g)) between pollen and ovule production per flower. Moreover, if selfing genotypes with similar P:O ratios differ in total gametic investment per flower, a positive r(g) between pollen and ovule production would be observed. In outcrossers, by contrast, male- and female-biased flowers and genotypes may have equal fitness and coexist at evolutionary equilibrium. In the absence of strong stabilizing selection on the P:O ratio, selection on this trait will be relaxed, resulting in independence or resource-based trade-offs between male and female investment. To test this prediction, we conducted artificial selection on pollen and ovule production per flower in two sister species with contrasting mating systems. The predominantly self-fertilizing species (Clarkia exilis) consistently exhibited a significant positive r(g) between pollen and ovule production while the outcrossing species (C. unguiculata) exhibited either a trade-off or independence between these traits. Clarkia exilis also exhibited much more highly canalized gender expression than C. unguiculata. Selection on pollen and ovule production resulted in little correlated change in the P:O ratio in the selfing exilis, while dramatic changes in the P:O ratio were observed in unguiculata. To test the common prediction that floral attractiveness should be positively genetically correlated with investment in male function, we examined the response of petal area to selection on pollen and ovule production and found that petal area was not consistently genetically correlated with gender expression in either species. Our results suggest that the joint evolutionary trajectory of primary sexual traits in hermaphroditic species will be affected by their mating systems; this should be taken into account in future theoretical and comparative empirical investigations.

Multiple mating and its relationship to alternative modes of gestation in male-pregnant versus female-pregnant fish species

PubMed Central

Avise, John C.; Liu, Jin-Xian

2010-01-01

We construct a verbal and graphical theory (the “fecundity-limitation hypothesis”) about how constraints on the brooding space for embryos probably truncate individual fecundity in male-pregnant and female-pregnant species in ways that should differentially influence selection pressures for multiple mating by males or by females. We then review the empirical literature on genetically deduced rates of multiple mating by the embryo-brooding parent in various fish species with three alternative categories of pregnancy: internal gestation by males, internal gestation by females, and external gestation (in nests) by males. Multiple mating by the brooding gender was common in all three forms of pregnancy. However, rates of multiple mating as well as mate numbers for the pregnant parent averaged higher in species with external as compared with internal male pregnancy, and also for dams in female-pregnant species versus sires in male-pregnant species. These outcomes are all consistent with the theory that different types of pregnancy have predictable consequences for a parent's brood space, its effective fecundity, its opportunities and rewards for producing half-sib clutches, and thereby its exposure to selection pressures for seeking multiple mates. Overall, we try to fit these fecundity-limitation phenomena into a broader conceptual framework for mating-system evolution that also includes anisogamy, sexual-selection gradients, parental investment, and other selective factors that can influence the relative proclivities of males versus females to seek multiple sexual partners. PMID:20956296

Monogamy in marine fishes.

PubMed

Whiteman, E A; Côte, I M

2004-05-01

The formation of long-term pair bonds in marine fish has elicited much empirical study. However, the evolutionary mechanisms involved remain contested and previous theoretical frameworks developed to explain monogamy in birds and mammals are not applicable to many cases of monogamy in marine fish. In this review, we summarise all reported occurrences of social monogamy in marine fish, which has so far been observed in 18 fish families. We test quantitatively the role of ecological and behavioural traits previously suggested to be important for the evolution of monogamy and show that monogamous species occur primarily in the tropics and are associated with coral reef environments in which territory defence and site attachment is facilitated. However, there is little evidence that obligately monogamous species are smaller in body size than species that can adopt a polygynous mating system. We review the evidence pertaining to six hypotheses suggested for the evolution of monogamous pair bonds: (1) biparental care, (2) habitat limitation, (3) low population density/low mate availability/low mobility, (4) increased reproductive efficiency, (5) territory defence, and (6) net benefit of single mate sequestration. We outline predictions and associated empirical tests that can distinguish between these hypotheses, and assess how generally each hypothesis explains monogamy within and between breeding periods for species with different types of territories (i.e. feeding only or feeding and breeding). Hypotheses (1) and (2) have limited applicability to marine fishes, while hypotheses (3)-(5) have little empirical support beyond the species for which they were designed. However, the role of paternal care in promoting monogamous pair bonds is not explicit in these hypotheses, yet paternal care has been reported in more than 70 monogamous marine fish. We show that paternal care may act to increase the likelihood of monogamy in combination with each of the proposed hypotheses through decreased benefits to males from searching for additional mates or increased advantages to females from sequestering a single high-quality mate. Among species defending breeding and feeding territories, the benefits, both within and between reproductive periods, of sequestering a single high-quality mate (hypothesis 6) appear to be the best explanation for socially monogamous pairs. For species without parental care (i.e. holding only feeding territories), territory defence (hypothesis 5) in combination with the benefits of guarding a large mate (hypothesis 6) could potentially explain most instances of monogamy. Empirical studies of marine fishes over the past two decades are therefore slowly changing the view of monogamy from a mating system imposed upon species by environmental constraints to one with direct benefits to both sexes.

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

Reconstruction of parental microsatellite genotypes reveals female polyandry and philopatry in the lemon shark, Negaprion brevirostris.

PubMed

Feldheim, Kevin A; Gruber, Samuel H; Ashley, Mary V

2004-10-01

Because sharks possess an unusual suite of reproductive characteristics, including internal fertilization, sperm storage, relatively low fecundity, and reproductive modes that range from oviparity to viviparity, they can provide important insight into the evolution of mating systems and sexual selection. Yet, to date, few studies have characterized behavioral and genetic mating systems in natural populations of sharks or other elasmobranchs. In this study, highly polymorphic microsatellite loci were used to examine breeding biology of a large coastal shark, the lemon shark, Negaprion brevirostris, at a tropical lagoon nursery. Over six years, 910 lemon sharks were sampled and genotyped. Young were assigned into sibling groups that were then used to reconstruct genotypes of unsampled adults. We assigned 707 of 735 young sharks to one of 45 female genotypes (96.2%), and 485 (66.0%) were assigned to a male genotype. Adult female sharks consistently returned to Bimini on a biennial cycle to give birth. Over 86% of litters had multiple sires. Such high levels of polyandry raise the possibility that polyandry evolved in viviparous sharks to reduce genetic incompatibilities between mother and embryos. We did not find a relationship between relatedness of mates and the number of offspring produced, indicating that inbreeding avoidance was probably not driving pre- or postcopulatory mate choice. Adult male sharks rarely sired more than one litter at Bimini and may mate over a broader geographic area.

Effects of polygamy on the activity/rest rhythm of male fruit flies Drosophila melanogaster

NASA Astrophysics Data System (ADS)

Vartak, Vivek Rohidas; Varma, Vishwanath; Sharma, Vijay Kumar

2015-02-01

Although polygamy is common in insects, its extent varies enormously among natural populations. Mating systems influence the evolution of reproductive traits and the difference in extent of polygamy between males and females may be a key factor in determining traits which come under the influence of sexual selection. Fruit flies Drosophila melanogaster are promiscuous as both males and females mate with multiple partners. Mating has severe consequences on the physiology and behaviour of flies, and it affects their activity/rest rhythm in a sex-specific manner. In this study, we attempted to discern the effects of mating with multiple partners as opposed to a single partner, or of remaining unmated, on the activity/rest rhythm of flies under cyclic semi-natural (SN) and constant dark (DD) conditions. The results revealed that while evening activity of mated flies was significantly reduced compared to virgins, polygamous males showed a more severe reduction compared to monogamous males. In contrast, though mated females showed reduction in evening activity compared to virgins, activity levels were not different between polygamous and monogamous females. Although there was no detectable effect of mating on clock period, power of the activity/rest rhythm was significantly reduced in mated females with no difference seen between polygamous and monogamous individuals. These results suggest that courtship motivation, represented by evening activity, is successively reduced in males due to mating with one or more partners, while in females, it does not depend on the number of mating partners. Based on these results we conclude that polygamy affects the activity/rest rhythm of fruit flies D. melanogaster in a sex-dependent manner.

Evolution of Life-History Trade-Offs in Mate Attractiveness and Health: Comment on Weeden and Sabini

ERIC Educational Resources Information Center

Geary, David C.

2005-01-01

J. Weeden and J. Sabini's finding of small to no relation between traits rated as attractive in a mate and health of that mate might be interpreted as consistent with C. Darwin's (1859) proposal that these traits are arbitrary signs of beauty. However, such a conclusion would be premature. A combination of consistent empirical findings with…

Not all sex ratios are equal: the Fisher condition, parental care and sexual selection.

PubMed

Jennions, Michael D; Fromhage, Lutz

2017-09-19

The term 'sex roles' encapsulates male-female differences in mate searching, competitive traits that increase mating/fertilization opportunities, choosiness about mates and parental care. Theoretical models suggest that biased sex ratios drive the evolution of sex roles. To model sex role evolution, it is essential to note that in most sexually reproducing species (haplodiploid insects are an exception), each offspring has one father and one mother. Consequently, the total number of offspring produced by each sex is identical, so the mean number of offspring produced by individuals of each sex depends on the sex ratio (Fisher condition). Similarly, the total number of heterosexual matings is identical for each sex. On average, neither sex can mate nor breed more often when the sex ratio is even. But equally common in which sex ratio? The Fisher condition only applies to some reproductive measures (e.g. lifetime offspring production or matings) for certain sex ratios (e.g. operational or adult sex ratio; OSR, ASR). Here, we review recent models that clarify whether a biased OSR, ASR or sex ratio at maturation (MSR) have a causal or correlational relationship with the evolution of sex differences in parental care and competitive traits-two key components of sex roles. We suggest that it is more fruitful to understand the combined effect of the MSR and mortality rates while caring and competing than that of the ASR itself. In short, we argue that the ASR does not have a causal role in the evolution of parental care. We point out, however, that the ASR can be a cue for adaptive phenotypic plasticity in how each sex invests in parental care.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'. © 2017 The Author(s).

KSC-97PC1109

NASA Image and Video Library

1997-07-22

Flight mechanics from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., inspect their work after mating the Cassini spacecraft to its launch vehicle adapter in KSC’s Payload Hazardous Servicing Facility. The adapter will later be mated to a Titan IV/Centaur expendable launch vehicle that will lift Cassini into space. Scheduled for launch in October, the Cassini mission, a joint US-European four-year orbital surveillance of Saturn's atmosphere and magnetosphere, its rings, and its moons, seeks insight into the origins and evolution of the early solar system. It will take seven years for the spacecraft to reach Saturn. JPL is managing the Cassini project for NASA

Social and behavioral barriers to pathogen transmission in wild animal populations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loehle, C.S.

Disease and pathogens have been studied as regulators of animal populations but not really as selective forces. The authors propose that pathogens can be major selective forces influencing social behaviors when these are successful at reducing disease transmission. The behaviors whose evolution could have been influenced by pathogen effects include group size, group isolation, mixed species flocking, migration, seasonal sociality, social avoidance, and dominance behaviors. Mate choice, mating system, and sexual selection are put in a new light when examined in terms of disease transmission. It is concluded that pathogen avoidance is a more powerful selective force than has heretoforemore » been recognized.« less

Darwin's legacy: the forms, function and sexual diversity of flowers

PubMed Central

Barrett, Spencer C. H.

2010-01-01

Charles Darwin studied floral biology for over 40 years and wrote three major books on plant reproduction. These works have provided the conceptual foundation for understanding floral adaptations that promote cross-fertilization and the mechanisms responsible for evolutionary transitions in reproductive systems. Many of Darwin's insights, gained from careful observations and experiments on diverse angiosperm species, remain remarkably durable today and have stimulated much current research on floral function and the evolution of mating systems. Here I review Darwin's seminal contributions to reproductive biology and provide an overview of the current status of research on several of the main topics to which he devoted considerable effort, including the consequences to fitness of cross- versus self-fertilization, the evolution and function of stylar polymorphisms, the adaptive significance of heteranthery, the origins of dioecy and related gender polymorphisms, and the transition from animal pollination to wind pollination. Post-Darwinian perspectives on floral function now recognize the importance of pollen dispersal and male outcrossed siring success in shaping floral adaptation. This has helped to link work on pollination biology and mating systems, two subfields of reproductive biology that remained largely isolated during much of the twentieth century despite Darwin's efforts towards integration. PMID:20047864

Addressing the Lack of Measurement Invariance for the Measure of Acceptance of the Theory of Evolution

NASA Astrophysics Data System (ADS)

Wagler, Amy; Wagler, Ron

2013-09-01

The Measure of Acceptance of the Theory of Evolution (MATE) was constructed to be a single-factor instrument that assesses an individual's overall acceptance of evolutionary theory. The MATE was validated and the scores resulting from the MATE were found to be reliable for the population of inservice high school biology teachers. However, many studies have utilized the MATE for different populations, such as university students enrolled in a biology or genetics course, high school students, and preservice teachers. This is problematic because the dimensionality and reliability of the MATE may not be consistent across populations. It is not uncommon in science education research to find examples where scales are applied to novel populations without proper assessment of the validity and reliability. In order to illustrate this issue, a case study is presented where the dimensionality of the MATE is evaluated for a population of non-science major preservice elementary teachers. With this objective in mind, factor analytic and item response models are fit to the observed data to provide evidence for or against a one-dimensional latent structure and to detect which items do not conform to the theoretical construct for this population. The results of this study call into question any findings and conclusions made using the MATE for a Hispanic population of preservice teachers and point out the error of assuming invariance across substantively different populations.

Molecular clocks and the early evolution of metazoan nervous systems.

PubMed

Wray, Gregory A

2015-12-19

The timing of early animal evolution remains poorly resolved, yet remains critical for understanding nervous system evolution. Methods for estimating divergence times from sequence data have improved considerably, providing a more refined understanding of key divergences. The best molecular estimates point to the origin of metazoans and bilaterians tens to hundreds of millions of years earlier than their first appearances in the fossil record. Both the molecular and fossil records are compatible, however, with the possibility of tiny, unskeletonized, low energy budget animals during the Proterozoic that had planktonic, benthic, or meiofaunal lifestyles. Such animals would likely have had relatively simple nervous systems equipped primarily to detect food, avoid inhospitable environments and locate mates. The appearance of the first macropredators during the Cambrian would have changed the selective landscape dramatically, likely driving the evolution of complex sense organs, sophisticated sensory processing systems, and diverse effector systems involved in capturing prey and avoiding predation. © 2015 The Author(s).

How Are Mate Preferences Linked with Actual Mate Selection? Tests of Mate Preference Integration Algorithms Using Computer Simulations and Actual Mating Couples

PubMed Central

Conroy-Beam, Daniel; Buss, David M.

2016-01-01

Prior mate preference research has focused on the content of mate preferences. Yet in real life, people must select mates among potentials who vary along myriad dimensions. How do people incorporate information on many different mate preferences in order to choose which partner to pursue? Here, in Study 1, we compare seven candidate algorithms for integrating multiple mate preferences in a competitive agent-based model of human mate choice evolution. This model shows that a Euclidean algorithm is the most evolvable solution to the problem of selecting fitness-beneficial mates. Next, across three studies of actual couples (Study 2: n = 214; Study 3: n = 259; Study 4: n = 294) we apply the Euclidean algorithm toward predicting mate preference fulfillment overall and preference fulfillment as a function of mate value. Consistent with the hypothesis that mate preferences are integrated according to a Euclidean algorithm, we find that actual mates lie close in multidimensional preference space to the preferences of their partners. Moreover, this Euclidean preference fulfillment is greater for people who are higher in mate value, highlighting theoretically-predictable individual differences in who gets what they want. These new Euclidean tools have important implications for understanding real-world dynamics of mate selection. PMID:27276030

How Are Mate Preferences Linked with Actual Mate Selection? Tests of Mate Preference Integration Algorithms Using Computer Simulations and Actual Mating Couples.

PubMed

Conroy-Beam, Daniel; Buss, David M

2016-01-01

Prior mate preference research has focused on the content of mate preferences. Yet in real life, people must select mates among potentials who vary along myriad dimensions. How do people incorporate information on many different mate preferences in order to choose which partner to pursue? Here, in Study 1, we compare seven candidate algorithms for integrating multiple mate preferences in a competitive agent-based model of human mate choice evolution. This model shows that a Euclidean algorithm is the most evolvable solution to the problem of selecting fitness-beneficial mates. Next, across three studies of actual couples (Study 2: n = 214; Study 3: n = 259; Study 4: n = 294) we apply the Euclidean algorithm toward predicting mate preference fulfillment overall and preference fulfillment as a function of mate value. Consistent with the hypothesis that mate preferences are integrated according to a Euclidean algorithm, we find that actual mates lie close in multidimensional preference space to the preferences of their partners. Moreover, this Euclidean preference fulfillment is greater for people who are higher in mate value, highlighting theoretically-predictable individual differences in who gets what they want. These new Euclidean tools have important implications for understanding real-world dynamics of mate selection.

Female sea lamprey shift orientation toward a conspecific chemical cue to escape a sensory trap

USGS Publications Warehouse

Brant, Cory O.; Johnson, Nicholas; Li, Ke; Buchinger, Tyler J.; Li, Weiming

2016-01-01

The sensory trap model of signal evolution hypothesizes that signalers adapt to exploit a cue used by the receiver in another context. Although exploitation of receiver biases can result in conflict between the sexes, deceptive signaling systems that are mutually beneficial drive the evolution of stable communication systems. However, female responses in the nonsexual and sexual contexts may become uncoupled if costs are associated with exhibiting a similar response to a trait in both contexts. Male sea lamprey (Petromyzon marinus) signal with a mating pheromone, 3-keto petromyzonol sulfate (3kPZS), which may be a match to a juvenile cue used by females during migration. Upstream movement of migratory lampreys is partially guided by 3kPZS, but females only move toward 3kPZS with proximal accuracy during spawning. Here, we use in-stream behavioral assays paired with gonad histology to document the transition of female preference for juvenile- and male-released 3kPZS that coincides with the functional shift of 3kPZS as a migratory cue to a mating pheromone. Females became increasingly biased toward the source of synthesized 3kPZS as their maturation progressed into the reproductive phase, at which point, a preference for juvenile odor (also containing 3kPZS naturally) ceased to exist. Uncoupling of female responses during migration and spawning makes the 3kPZS communication system a reliable means of synchronizing mate search. The present study offers a rare example of a transition in female responses to a chemical cue between nonsexual and sexual contexts, provides insights into the origins of stable communication signaling systems.

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

Direct benefits of choosing a high-fitness mate can offset the indirect costs associated with intralocus sexual conflict.

PubMed

Pischedda, Alison; Chippindale, Adam K

2017-06-01

Intralocus sexual conflict generates a cost to mate choice: high-fitness partners transmit genetic variation that confers lower fitness to offspring of the opposite sex. Our earlier work in the fruit fly, Drosophila melanogaster, revealed that these indirect genetic costs were sufficient to reverse potential "good genes" benefits of sexual selection. However, mate choice can also confer direct fitness benefits by inducing larger numbers of progeny. Here, we consider whether direct benefits through enhanced fertility could offset the costs associated with intralocus sexual conflict in D. melanogaster. Using hemiclonal analysis, we found that females mated to high-fitness males produced 11% more offspring compared to those mated to low-fitness males, and high-fitness females produced 34% more offspring than low-fitness females. These direct benefits more than offset the reduction in offspring fitness caused by intralocus sexual conflict, creating a net fitness benefit for each sex to pairing with a high-fitness partner. Our findings highlight the need to consider both direct and indirect effects when investigating the fitness impacts of mate choice. Direct fitness benefits may shelter sexually antagonistic alleles from selection, suggesting a novel mechanism for the maintenance of fitness variation. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Evolution of mate-harm, longevity and behaviour in male fruit flies subjected to different levels of interlocus conflict.

PubMed

Nandy, Bodhisatta; Gupta, Vanika; Sen, Sharmi; Udaykumar, Niveda; Samant, Manas Arun; Ali, Syed Zeeshan; Prasad, Nagaraj Guru

2013-09-28

Interlocus conflict predicts (a) evolution of traits, beneficial to males but detrimental to females and (b) evolution of aging and life-span under the influence of the cost of bearing these traits. However, there are very few empirical investigations shedding light on these predictions. Those that do address these issues, mostly reported response of male reproductive traits or the lack of it and do not address the life-history consequence of such evolution. Here, we test both the above mentioned predictions using experimental evolution on replicate populations of Drosophila melanogaster. We present responses observed after >45 generations of altered levels of interlocus conflict (generated by varying the operational sex ratio). Males from the male biased (high conflict, M-regime) regime evolved higher spontaneous locomotor activity and courtship frequency. Females exposed to these males were found to have higher mortality rate. Males from the female biased regime (low conflict, F-regime) did not evolve altered courtship frequency and activity. However, progeny production of females continuously exposed to F-males was significantly higher than the progeny production of females exposed to M-males indicating that the F-males are relatively benign towards their mates. We found that males from male biased regime lived shorter compared to males from the female biased regime. F-males (evolving under lower levels of sexual conflict) evolved decreased mate harming ability indicating the cost of maintenance of the suit of traits that cause mate-harm. The M-males (evolving under higher levels sexual conflict) caused higher female mortality indicating that they had evolved increased mate harming ability, possibly as a by product of increased reproduction related activity. There was a correlated evolution of life-history of the M and F-males. M-regime males lived shorter compared to the males from F-regime, possibly due to the cost of investing more in reproductive traits. In combination, these results suggest that male reproductive traits and life-history traits can evolve in response to the altered levels of interlocus sexual conflict.

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

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.

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.

Egg Viability, Mating Frequency and Male Mating Ability Evolve in Populations of Drosophila melanogaster Selected for Resistance to Cold Shock

PubMed Central

Singh, Karan; Kochar, Ekta; Prasad, N. G.

2015-01-01

Background Ability to resist temperature shock is an important component of fitness of insects and other ectotherms. Increased resistance to temperature shock is known to affect life-history traits. Temperature shock is also known to affect reproductive traits such as mating ability and viability of gametes. Therefore selection for increased temperature shock resistance can affect the evolution of reproductive traits. Methods We selected replicate populations of Drosophila melanogaster for resistance to cold shock. We then investigated the evolution of reproductive behavior along with other components of fitness- larval survivorship, adult mortality, fecundity, egg viability in these populations. Results We found that larval survivorship, adult mortality and fecundity post cold shock were not significantly different between selected and control populations. However, compared to the control populations, the selected populations laid significantly higher percentage of fertile eggs (egg viability) 24 hours post cold shock. The selected populations had higher mating frequency both with and without cold shock. After being subjected to cold shock, males from the selected populations successfully mated with significantly more non-virgin females and sired significantly more progeny compared to control males. Conclusions A number of studies have reported the evolution of survivorship in response to selection for temperature shock resistance. Our results clearly indicate that adaptation to cold shock can involve changes in components of reproductive fitness. Our results have important implications for our understanding of how reproductive behavior can evolve in response to thermal stress. PMID:26065704

Genetic caste polymorphism and the evolution of polyandry in Atta leaf-cutting ants

NASA Astrophysics Data System (ADS)

Evison, Sophie Elizabeth Frances; Hughes, William O. H.

2011-08-01

Multiple mating by females with different males (polyandry) is difficult to explain in many taxa because it carries significant costs to females, yet benefits are often hard to identify. Polyandry is a derived trait in social insects, the evolutionary origins of which remain unclear. One of several leading hypotheses for its evolution is that it improves division of labour by increasing intra-colonial genetic diversity. Division of labour is a key player in the ecological success of social insects, and in many successful species of ants is based on morphologically distinct castes of workers, each with their own task specialisations. Atta leaf-cutting ants exhibit one of the most extreme and complicated forms of morphologically specialised worker castes and have been reported to be polyandrous but with relatively low mating frequencies (~2.5 on average). Here, we show for the first time that there is a significant genetic influence on worker size in Atta colombica leaf-cutting ants. We also provide the first estimate of the mating frequency of Atta cephalotes (four matings) and, by analysing much higher within-colony sample sizes, find that Atta are more polyandrous than previously thought (approximately six to seven matings). The results show that high polyandry and a genetic influence on worker caste are present in both genera of leaf-cutting ants and add weight to the hypothesis that division of labour is a potential driver of the evolution of polyandry in this clade of ants.

Biased learning affects mate choice in a butterfly.

PubMed

Westerman, Erica L; Hodgins-Davis, Andrea; Dinwiddie, April; Monteiro, Antónia

2012-07-03

Early acquisition of mate preferences or mate-preference learning is associated with signal diversity and speciation in a wide variety of animal species. However, the diversity of mechanisms of mate-preference learning across taxa remains poorly understood. Using the butterfly Bicyclus anynana we uncover a mechanism that can lead to directional sexual selection via mate-preference learning: a bias in learning enhanced ornamentation, which is independent of preexisting mating biases. Naïve females mated preferentially with wild-type males over males with enhanced wing ornamentation, but females briefly exposed to enhanced males mated significantly more often with enhanced males. In contrast, females exposed to males with reduced wing ornamentation did not learn to prefer drab males. Thus, we observe both a learned change of a preexisting mating bias, and a bias in ability to learn enhanced male ornaments over reduced ornaments. Our findings demonstrate that females are able to change their preferences in response to a single social event, and suggest a role for biased learning in the evolution of visual sexual ornamentation.

Coy Males and Seductive Females in the Sexually Cannibalistic Colonial Spider, Cyrtophora citricola.

PubMed

Yip, Eric C; Berner-Aharon, Na'ama; Smith, Deborah R; Lubin, Yael

2016-01-01

The abundance of sperm relative to eggs selects for males that maximize their number of mates and for females that choose high quality males. However, in many species, males exercise mate choice, even when they invest little in their offspring. Sexual cannibalism may promote male choosiness by limiting the number of females a male can inseminate and by biasing the sex ratio toward females because, while females can reenter the mating pool, cannibalized males cannot. These effects may be insufficient for male choosiness to evolve, however, if males face low sequential encounter rates with females. We hypothesized that sexual cannibalism should facilitate the evolution of male choosiness in group living species because a male is likely to encounter multiple receptive females simultaneously. We tested this hypothesis in a colonial orb-weaving spider, Cyrtophora citricola, with a high rate of sexual cannibalism. We tested whether mated females would mate with multiple males, and thereby shift the operational sex ratio toward females. We also investigated whether either sex chooses mates based on nutritional state and age, and whether males choose females based on reproductive state. We found that females are readily polyandrous and exhibit no mate choice related to male feeding or age. Males courted more often when the male was older and the female was younger, and males copulated more often with well-fed females. The data show that males are choosier than females for the traits we measured, supporting our hypothesis that group living and sexual cannibalism may together promote the evolution of male mate choice.

Coy Males and Seductive Females in the Sexually Cannibalistic Colonial Spider, Cyrtophora citricola

PubMed Central

Yip, Eric C.; Berner-Aharon, Na’ama; Smith, Deborah R.; Lubin, Yael

2016-01-01

The abundance of sperm relative to eggs selects for males that maximize their number of mates and for females that choose high quality males. However, in many species, males exercise mate choice, even when they invest little in their offspring. Sexual cannibalism may promote male choosiness by limiting the number of females a male can inseminate and by biasing the sex ratio toward females because, while females can reenter the mating pool, cannibalized males cannot. These effects may be insufficient for male choosiness to evolve, however, if males face low sequential encounter rates with females. We hypothesized that sexual cannibalism should facilitate the evolution of male choosiness in group living species because a male is likely to encounter multiple receptive females simultaneously. We tested this hypothesis in a colonial orb-weaving spider, Cyrtophora citricola, with a high rate of sexual cannibalism. We tested whether mated females would mate with multiple males, and thereby shift the operational sex ratio toward females. We also investigated whether either sex chooses mates based on nutritional state and age, and whether males choose females based on reproductive state. We found that females are readily polyandrous and exhibit no mate choice related to male feeding or age. Males courted more often when the male was older and the female was younger, and males copulated more often with well-fed females. The data show that males are choosier than females for the traits we measured, supporting our hypothesis that group living and sexual cannibalism may together promote the evolution of male mate choice. PMID:27249787

The evolution of social monogamy in mammals.

PubMed

Lukas, D; Clutton-Brock, T H

2013-08-02

The evolution of social monogamy has intrigued biologists for over a century. Here, we show that the ancestral condition for all mammalian groups is of solitary individuals and that social monogamy is derived almost exclusively from this social system. The evolution of social monogamy does not appear to have been associated with a high risk of male infanticide, and paternal care is a consequence rather than a cause of social monogamy. Social monogamy has evolved in nonhuman mammals where breeding females are intolerant of each other and female density is low, suggesting that it represents a mating strategy that has developed where males are unable to defend access to multiple females.

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.

Evolution of synthetic signaling scaffolds by recombination of modular protein domains.

PubMed

Lai, Andicus; Sato, Paloma M; Peisajovich, Sergio G

2015-06-19

Signaling scaffolds are proteins that interact via modular domains with multiple partners, regulating signaling networks in space and time and providing an ideal platform from which to alter signaling functions. However, to better exploit scaffolds for signaling engineering, it is necessary to understand the full extent of their modularity. We used a directed evolution approach to identify, from a large library of randomly shuffled protein interaction domains, variants capable of rescuing the signaling defect of a yeast strain in which Ste5, the scaffold in the mating pathway, had been deleted. After a single round of selection, we identified multiple synthetic scaffold variants with diverse domain architectures, able to mediate mating pathway activation in a pheromone-dependent manner. The facility with which this signaling network accommodates changes in scaffold architecture suggests that the mating signaling complex does not possess a single, precisely defined geometry into which the scaffold has to fit. These relaxed geometric constraints may facilitate the evolution of signaling networks, as well as their engineering for applications in synthetic biology.

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.

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.

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, strongly bonded groups, and the evolution of human social structure.

PubMed

Chapais, Bernard

2013-01-01

Human social evolution has most often been treated in a piecemeal fashion, with studies focusing on the evolution of specific components of human society such as pair-bonding, cooperative hunting, male provisioning, grandmothering, cooperative breeding, food sharing, male competition, male violence, sexual coercion, territoriality, and between-group conflicts. Evolutionary models about any one of those components are usually concerned with two categories of questions, one relating to the origins of the component and the other to its impact on the evolution of human cognition and social life. Remarkably few studies have been concerned with the evolution of the entity that integrates all components, the human social system itself. That social system has as its core feature human social structure, which I define here as the common denominator of all human societies in terms of group composition, mating system, residence patterns, and kinship structures. The paucity of information on the evolution of human social structure poses substantial problems because that information is useful, if not essential, to assess both the origins and impact of any particular aspect of human society. Copyright © 2013 Wiley Periodicals, Inc.

Variance-based selection may explain general mating patterns in social insects.

PubMed

Rueppell, Olav; Johnson, Nels; Rychtár, Jan

2008-06-23

Female mating frequency is one of the key parameters of social insect evolution. Several hypotheses have been suggested to explain multiple mating and considerable empirical research has led to conflicting results. Building on several earlier analyses, we present a simple general model that links the number of queen matings to variance in colony performance and this variance to average colony fitness. The model predicts selection for multiple mating if the average colony succeeds in a focal task, and selection for single mating if the average colony fails, irrespective of the proximate mechanism that links genetic diversity to colony fitness. Empirical support comes from interspecific comparisons, e.g. between the bee genera Apis and Bombus, and from data on several ant species, but more comprehensive empirical tests are needed.

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.

Are relationships between pollen-ovule ratio and pollen and seed size explained by sex allocation?

PubMed

Burd, Martin

2011-10-01

Positive correlations between pollen-ovule ratio and seed size, and negative correlations between pollen-ovule ratio and pollen grain size have been noted frequently in a wide variety of angiosperm taxa. These relationships are commonly explained as a consequence of sex allocation on the basis of a simple model proposed by Charnov. Indeed, the theoretical expectation from the model has been the basis for interest in the empirical pattern. However, the predicted relationship is a necessary consequence of the mathematics of the model, which therefore has little explanatory power, even though its predictions are consistent with empirical results. The evolution of pollen-ovule ratios is likely to depend on selective factors affecting mating system, pollen presentation and dispensing, patterns of pollen receipt, pollen tube competition, female mate choice through embryo abortion, as well as genetic covariances among pollen, ovule, and seed size and other reproductive traits. To the extent the empirical correlations involving pollen-ovule ratios are interesting, they will need explanation in terms of a suite of selective factors. They are not explained simply by sex allocation trade-offs. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

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.

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.

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.

Mating System Evolution under Strong Pollen Limitation: Evidence of Disruptive Selection through Male and Female Fitness in Clarkia xantiana.

PubMed

Briscoe Runquist, Ryan D; Geber, Monica A; Pickett-Leonard, Michael; Moeller, David A

2017-05-01

Selection on floral traits in hermaphroditic plants is determined by both male and female reproductive success. However, predictions regarding floral trait and mating system evolution are often based solely on female fitness. Selection via male fitness has the potential to affect the outcomes of floral evolution. In this study, we used paternity analysis to assess individual selfing rates and selection on floral traits via male and female fitness in an experimental population of Clarkia xantiana where pollen limitation of seed set was strong. We detected selection through both female and male fitness with reinforcing or noninterfering patterns of selection through the two sex functions. For female fitness, selection favored reduced herkogamy and protandry, traits that promote increased autonomous selfing. For male fitness, selection on petal area was disruptive, with higher trait values conferring greater pollinator attraction and outcross siring success and smaller trait values leading to higher selfed siring success. Combining both female and male fitness, selection on petal area and protandry was disruptive because intermediate phenotypes were less successful as both males and females. Finally, functional relationships among male and female fertility components indicated that selfing resulted in seed discounting and pollen discounting. Under these functional relationships, the evolutionarily stable selfing rate can be intermediate or predominantly selfing or outcrossing, depending on the segregating load of deleterious mutations.

Estimating selection through male fitness: three complementary methods illuminate the nature and causes of selection on flowering time

PubMed Central

Austen, Emily J.; Weis, Arthur E.

2016-01-01

Our understanding of selection through male fitness is limited by the resource demands and indirect nature of the best available genetic techniques. Applying complementary, independent approaches to this problem can help clarify evolution through male function. We applied three methods to estimate selection on flowering time through male fitness in experimental populations of the annual plant Brassica rapa: (i) an analysis of mating opportunity based on flower production schedules, (ii) genetic paternity analysis, and (iii) a novel approach based on principles of experimental evolution. Selection differentials estimated by the first method disagreed with those estimated by the other two, indicating that mating opportunity was not the principal driver of selection on flowering time. The genetic and experimental evolution methods exhibited striking agreement overall, but a slight discrepancy between the two suggested that negative environmental covariance between age at flowering and male fitness may have contributed to phenotypic selection. Together, the three methods enriched our understanding of selection on flowering time, from mating opportunity to phenotypic selection to evolutionary response. The novel experimental evolution method may provide a means of examining selection through male fitness when genetic paternity analysis is not possible. PMID:26911957

Environmental change mediates mate choice for an extended phenotype, but not for mate quality.

PubMed

Head, Megan L; Fox, Rebecca J; Barber, Iain

2017-01-01

Sexual cues, including extended phenotypes, are expected to be reliable indicators of male genetic quality and/or provide information on parental quality. However, the reliability of these cues may be dependent on stability of the environment, with heterogeneity affecting how selection acts on such traits. Here, we test how environmental change mediates mate choice for multiple sexual traits, including an extended phenotype--the structure of male-built nests - in stickleback fish. First, we manipulated the dissolved oxygen (DO) content of water to create high or low DO environments in which male fish built nests. Then we recorded the mate choice of females encountering these males (and their nests), under either the same or reversed DO conditions. Males in high DO environments built more compact nests than those in low DO conditions and males adjusted their nest structure in response to changing conditions. Female mate choice for extended phenotype (male nests) was environmentally dependent (females chose more compact nests in high DO conditions), while female choice for male phenotype was not (females chose large, vigorous males regardless of DO level). Examining mate choice in this dynamic context suggests that females evaluate the reliability of multiple sexual cues, taking into account environmental heterogeneity. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Co-Evolution of the Mating Position and Male Genitalia in Insects: A Case Study of a Hangingfly

PubMed Central

Gao, Qionghua; Hua, Baozhen

2013-01-01

Hangingflies are unique for the male providing a nuptial gift to the female during mating and taking a face-to-face hanging copulation with the female. Their male genitalia are peculiar for an extremely elongated penisfilum, a pair of well-developed epandrial lobes (9th tergum), and a pair of degenerated gonostyli. However, the co-evolution of their face-to-face copulation behavior and the male genitalia has rarely been studied hitherto. In this paper the mating behavior of the hangingfly Bittacus planus Cheng, 1949 was observed under laboratory conditions, and the morphology of the male and female external genitalia was investigated using light and scanning electron microscopy. The male provides an insect prey as a nuptial gift to the female in courtship and mating process, and commits a face-to-face copulation. During copulation, the male abdomen twists temporarily about 180° to accommodate their face-to-face mating position. The aedeagal complex has an extremely elongated penisfilum, corresponding to the elongated spermathecal duct of the female. The well-developed epandrial lobes serve as claspers to grasp the female subgenital plate during copulation, replacing the function of gonostyli, which are greatly reduced in Bittacidae. The modified proctiger assists the penisfilum to stretch and to enter into the female spermathecal duct. The possible reasons why this species might mate face-to-face are briefly discussed. PMID:24312490

Co-evolution of the mating position and male genitalia in insects: a case study of a hangingfly.

PubMed

Gao, Qionghua; Hua, Baozhen

2013-01-01

Hangingflies are unique for the male providing a nuptial gift to the female during mating and taking a face-to-face hanging copulation with the female. Their male genitalia are peculiar for an extremely elongated penisfilum, a pair of well-developed epandrial lobes (9th tergum), and a pair of degenerated gonostyli. However, the co-evolution of their face-to-face copulation behavior and the male genitalia has rarely been studied hitherto. In this paper the mating behavior of the hangingfly Bittacus planus Cheng, 1949 was observed under laboratory conditions, and the morphology of the male and female external genitalia was investigated using light and scanning electron microscopy. The male provides an insect prey as a nuptial gift to the female in courtship and mating process, and commits a face-to-face copulation. During copulation, the male abdomen twists temporarily about 180° to accommodate their face-to-face mating position. The aedeagal complex has an extremely elongated penisfilum, corresponding to the elongated spermathecal duct of the female. The well-developed epandrial lobes serve as claspers to grasp the female subgenital plate during copulation, replacing the function of gonostyli, which are greatly reduced in Bittacidae. The modified proctiger assists the penisfilum to stretch and to enter into the female spermathecal duct. The possible reasons why this species might mate face-to-face are briefly discussed.

Neural mechanisms of mother-infant bonding and pair bonding: Similarities, differences, and broader implications.

PubMed

Numan, Michael; Young, Larry J

2016-01-01

This article is part of a Special Issue "Parental Care". Mother-infant bonding is a characteristic of virtually all mammals. The maternal neural system may have provided the scaffold upon which other types of social bonds in mammals have been built. For example, most mammals exhibit a polygamous mating system, but monogamy and pair bonding between mating partners occur in ~5% of mammalian species. In mammals, it is plausible that the neural mechanisms that promote mother-infant bonding have been modified by natural selection to establish the capacity to develop a selective bond with a mate during the evolution of monogamous mating strategies. Here we compare the details of the neural mechanisms that promote mother-infant bonding in rats and other mammals with those that underpin pair bond formation in the monogamous prairie vole. Although details remain to be resolved, remarkable similarities and a few differences between the mechanisms underlying these two types of bond formation are revealed. For example, amygdala and nucleus accumbens-ventral pallidum (NA-VP) circuits are involved in both types of bond formation, and dopamine and oxytocin actions within NA appear to promote the synaptic plasticity that allows either infant or mating partner stimuli to persistently activate NA-VP attraction circuits, leading to an enduring social attraction and bonding. Further, although the medial preoptic area is essential for maternal behavior, its role in pair bonding remains to be determined. Our review concludes by examining the broader implications of this comparative analysis, and evidence is provided that the maternal care system may have also provided the basic neural foundation for other types of strong social relationships, beyond pair bonding, in mammals, including humans. Copyright © 2015 Elsevier Inc. All rights reserved.

Neural mechanisms of mother-infant bonding and pair bonding: Similarities, differences, and broader implications

PubMed Central

Numan, Michael; Young, Larry J.

2015-01-01

Mother-infant bonding is a characteristic of virtually all mammals. The maternal neural system may have provided the scaffold upon which other types of social bonds in mammals have been built. For example, most mammals exhibit a polygamous mating system, but monogamy and pair bonding between mating partners occurs in ∼5% of mammalian species. In mammals, it is plausible that the neural mechanisms that promote mother-infant bonding have been modified by natural selection to establish the capacity to develop a selective bond with a mate during the evolution of monogamous mating strategies. Here we compare the details of the neural mechanisms that promote mother-infant bonding in rats and other mammals with those that underpin pair bond formation in the monogamous prairie vole. Although details remain to be resolved, remarkable similarities and a few differences between the mechanisms underlying these two types of bond formation are revealed. For example, amygdala and nucleus accumbens-ventral pallidum (NA-VP) circuits are involved in both types of bond formation, and dopamine and oxytocin action within NA appears to promote the synaptic plasticity that allows either infant or mating partner stimuli to persistently activate NA-VP attraction circuits, leading to an enduring social attraction and bonding. Further, although the medial preoptic area is essential for maternal behavior, its role in pair bonding remains to be determined. Our review concludes by examining the broader implications of this comparative analysis, and evidence is provided that the maternal care system may have also provided the basic neural foundation for other types of strong social relationships, beyond pair bonding, in mammals, including humans. PMID:26062432

Knockdown of a metathoracic scent gland desaturase enhances the production of (E)-4-oxo-2-hexenal and suppresses female sexual attraction in the plant bug, Adelphocoris suturalis

USDA-ARS?s Scientific Manuscript database

Insect sex pheromones (SPs) are central to mate-finding behavior, and play an essential role in the survival and reproduction of organisms. Understanding the roles, biosynthetic pathways, and evolution of insect chemical communication systems has been an exciting challenge for biologists. Compared w...

The evolutionary history of colour polymorphism in Ischnura damselflies.

PubMed

Sánchez-Guillén, Rosa A; Cordero-Rivera, Adolfo; Rivas-Torres, Anais; Wellenreuther, Maren; Bybee, Seth; Hansson, Bengt; Velasquez-Vélez, María I; Realpe, Emilio; Chávez-Ríos, Jesús R; Villalobos, Fabricio; Dumont, Henri

2018-05-10

A major challenge in evolutionary biology consists of understanding how genetic and phenotypic variation is created and maintained. In the present study, we investigated the origin(s) and evolutionary patterns of the female-limited colour polymorphism in ischnuran damselflies. These consist of the presence of one to three colour morphs: one androchrome morph with a colouration that is similar to the male, and two gynochrome morphs (infuscans and aurantiaca) with female-specific colouration. We (i) documented the colour and mating system of 44 of the 75 taxa within the genus Ischnura, (ii) reconstructed the evolutionary history of colour and mating system to identify the ancestral state, (iii) evaluated the stability of the colour morph status over time, and (iv) tested for a correlation between colour and mating system. We found that the ances tral female colour of Ischnura was monomorphic and aurantiaca and that colour morph status changed over time; characterised by many gains and losses across the species tree. Our results further showed that colour polymorphism is significantly more frequent among polyandric species, whereas monandric species tend to be monomorphic. Research on some Ischnura species has shown that colour morphs have evolved to reduce male mating harassment, and our finding that the same phenotypic morphs have evolved multiple times (convergent evolution) suggests that several species in this genus might be experiencing similar selective pressures. This article is protected by copyright. All rights reserved. This article is protected by copyright. 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.

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.

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.

Sperm Bindin Divergence under Sexual Selection and Concerted Evolution in Sea Stars.

PubMed

Patiño, Susana; Keever, Carson C; Sunday, Jennifer M; Popovic, Iva; Byrne, Maria; Hart, Michael W

2016-08-01

Selection associated with competition among males or sexual conflict between mates can create positive selection for high rates of molecular evolution of gamete recognition genes and lead to reproductive isolation between species. We analyzed coding sequence and repetitive domain variation in the gene encoding the sperm acrosomal protein bindin in 13 diverse sea star species. We found that bindin has a conserved coding sequence domain structure in all 13 species, with several repeated motifs in a large central region that is similar among all sea stars in organization but highly divergent among genera in nucleotide and predicted amino acid sequence. More bindin codons and lineages showed positive selection for high relative rates of amino acid substitution in genera with gonochoric outcrossing adults (and greater expected strength of sexual selection) than in selfing hermaphrodites. That difference is consistent with the expectation that selfing (a highly derived mating system) may moderate the strength of sexual selection and limit the accumulation of bindin amino acid differences. The results implicate both positive selection on single codons and concerted evolution within the repetitive region in bindin divergence, and suggest that both single amino acid differences and repeat differences may affect sperm-egg binding and reproductive compatibility. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Experimental evolution: Assortative mating and sexual selection, independent of local adaptation, lead to reproductive isolation in the nematode Caenorhabditis remanei.

PubMed

Castillo, Dean M; Burger, Melissa K; Lively, Curtis M; Delph, Lynda F

2015-12-01

Using experimental evolution, we investigated the contributions of ecological divergence, sexual selection, and genetic drift to the evolution of reproductive isolation in Caenorhabditis remanei. The nematodes were reared on two different environments for 100 generations. They were assayed for fitness on both environments after 30, 64, and 100 generations, and hybrid fitness were analyzed after 64 and 100 generations. Mating propensity within and between populations was also analyzed. The design allowed us to determine whether local adaptation was synchronous with pre- and postzygotic reproductive isolation. Prezygotic isolation evolved quickly but was unconnected with adaptation to the divergent environments. Instead, prezygotic isolation was driven by mate preferences favoring individuals from the same replicate population. A bottleneck treatment, meant to enhance the opportunity for genetic drift, had no effect on prezygotic isolation. Postzygotic isolation occurred in crosses where at least one population had a large fitness advantage in its "home" environment. Taken together, our results suggest that prezygotic isolation did not depend on drift or adaptation to divergent environments, but instead resulted from differences in sexual interactions within individual replicates. Furthermore, our results suggest that postzygotic isolation can occur between populations even when only one population has greater fitness in its home environment. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Nuptial feeding of spermless spermatophores in the Hawaiian swordtail cricket, Laupala pacifica (Gryllidae: Triginodiinae)

NASA Astrophysics Data System (ADS)

Decarvalho, Tagide N.; Shaw, Kerry L.

2005-10-01

Crickets in the genus Laupala (subfamily Trigonidiinae) have an elaborate courtship system, defined by a highly ritualized serial transfer of multiple spermatophores. Males produce multiple “micro” spermatophores followed by a final “macro” spermatophore during a single mating bout. Remarkably, the microspermatophores of L. cerasina, the first species whose mating system was studied in detail, were discovered to be spermless. However, in a study of another species, L. pacifica, sperm transfer was reported after every copulation suggesting that L. pacifica microspermatophores contain sperm. The presence or absence of sperm in the microspermatophore has important implications for the evolution of this exaggerated courtship system and the origin of nuptial gifts. In this study, we systematically examined L. pacifica spermatophore contents for sperm using a fluorescent nuclear stain. We detected sperm only in macrospermatophores. This finding suggests that spermless microspermatophores are typical for Laupala; thus, to determine the origin of this highly modified phenotype will require comparative analyses with closely related outgroups that exhibit less exaggerated courtship systems.

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.

KSC-03PD-1090

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- The port fairing closes in on the Galaxy Evolution Explorer (GALEX). The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

Ecological context of the evolution of self-pollination in Clarkia xantiana: population size, plant communities, and reproductive assurance.

PubMed

Moeller, David A; Geber, Monica A

2005-04-01

The repeated evolutionary transition from outcrossing to self-pollination in flowering plants has been suggested to occur because selfing provides reproductive assurance. Reports from biogeographical and ecological surveys indicate that selfing taxa are often associated with stressful and ephemeral environments, situations in which plant abundance is low (e.g., Baker's law) and with novel plant communities, however experimental tests of ecological hypotheses are few. In this study, we examined the ecological context of selection on mating system traits (herkogamy and protandry) in a California annual, Clarkia xantiana, where natural selfing populations differ from outcrossing populations in that they are often of small size or low density and occur mainly outside the range of pollinator-sharing congeners. We constructed artificial populations of plants with broad genetic variation in floral traits and manipulated two ecological factors, plant population size, and the presence versus absence of pollinator-sharing congeners, in the center of the geographic range of outcrossing populations. We found evidence for context-dependent selection on herkogamy and protandry via female fitness in which reduced traits, which promote autonomous selfing, were favored in small populations isolated from congeners whereas selection was comparatively weak in large populations or when congeners were present. In small, isolated populations, the fertility of plants with low herkogamy or protandry was elevated by 66% and 58%, respectively, compared to those with high herkogamy or protandry. The presence of pollinator-sharing congeners augmented bee visitation rates to C. xantiana flowers by 47% for all bees and by 93% for pollen specialists. By facilitating pollinator visitation, congeners mitigated selection on mating system traits in small populations, where outcross mating success is often low (the Allee effect). We also found support for the hypothesis that pollinator availability directly influenced variation in the strength of selection on herkogamy among populations. The striking parallels between our experimental results and patterns of variation in ecological factors across the geographic range of outcrossing and selfing populations suggest that reproductive assurance may play a central role in directing mating system evolution in C. xantiana.

Cross-generational effects of sexual harassment on female fitness in the guppy.

PubMed

Gasparini, Clelia; Devigili, Alessandro; Pilastro, Andrea

2012-02-01

Sexual harassment is a common outcome of sexual conflict over mating rate. A large number of studies have identified several direct costs to females of sexual harassment including energy expenditure and reduced foraging ability. However, the fitness consequences of sexual harassment for descendants have rarely been investigated. Here, we manipulated the level of sexual harassment and mating rate in two groups of female guppies, Poecilia reticulata, a live-bearing fish in which sexual conflict over mating rate is particularly pronounced. Each female was allowed to interact with three males for one day (low sexual harassment, LSH) or for eight days (high sexual harassment, HSH) during each breeding cycle throughout their life. Female lifetime fecundity did not differ between the groups, but we found a strong effect on offspring fitness. HSH females produced (1) daughters with smaller bodies and (2) sons with shorter gonopodia, which were less attractive to females and less successful in coercive matings than their LSH counterparts. Although these results may be influenced by the indirect effects of sex ratio differences between treatments, they suggest that sexual harassment and elevated mating rate can have negative cross-generational fitness effects and more profound evolutionary consequences than currently thought. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

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.

Sperm competition games: a general model for precopulatory male-male competition.

PubMed

Parker, Geoff A; Lessells, Catherine M; Simmons, Leigh W

2013-01-01

Reproductive males face a trade-off between expenditure on precopulatory male-male competition--increasing the number of females that they secure as mates--and sperm competition--increasing their fertilization success with those females. Previous sperm allocation models have focused on scramble competition in which males compete by searching for mates and the number of matings rises linearly with precopulatory expenditure. However, recent studies have emphasized contest competition involving precopulatory expenditure on armaments, where winning contests may be highly dependent on marginal increases in relative armament level. Here, we develop a general model of sperm allocation that allows us to examine the effect of all forms of precopulatory competition on sperm allocation patterns. The model predicts that sperm allocation decreases if either the "mate-competition loading,"a, or the number of males competing for each mating, M, increases. Other predictions remain unchanged from previous models: (i) expenditure per ejaculate should increase and then decrease, and (ii) total postcopulatory expenditure should increase, as the level of sperm competition increases. A negative correlation between a and M is biologically plausible, and may buffer deviations from the previous models. There is some support for our predictions from comparative analyses across dung beetle species and frog populations. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Rapid loss of behavioral plasticity and immunocompetence under intense sexual selection.

PubMed

van Lieshout, Emile; McNamara, Kathryn B; Simmons, Leigh W

2014-09-01

Phenotypic plasticity allows animals to maximize fitness by conditionally expressing the phenotype best adapted to their environment. Although evidence for such adjustment in reproductive tactics is common, little is known about how phenotypic plasticity evolves in response to sexual selection. We examined the effect of sexual selection intensity on phenotypic plasticity in mating behavior using the beetle Callosobruchus maculatus. Male genital spines harm females during mating and females exhibit copulatory kicking, an apparent resistance trait aimed to dislodge mating males. After exposing individuals from male- and female-biased experimental evolution lines to male- and female-biased sociosexual environments, we examined behavioral plasticity in matings with standard partners. While females from female-biased lines kicked sooner after exposure to male-biased sociosexual contexts, in male-biased lines this plasticity was lost. Ejaculate size did not diverge in response to selection history, but males from both treatments exhibited plasticity consistent with sperm competition intensity models, reducing size as the number of competitors increased. Analysis of immunocompetence revealed reduced immunity in both sexes in male-biased lines, pointing to increased reproductive costs under high sexual selection. These results highlight how male and female reproductive strategies are shaped by interactions between phenotypically plastic and genetic mechanisms of sexual trait expression. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

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.

Cooperative breeding and monogamy in mammalian societies

PubMed Central

Lukas, Dieter; Clutton-Brock, Tim

2012-01-01

Comparative studies of social insects and birds show that the evolution of cooperative and eusocial breeding systems has been confined to species where females mate completely or almost exclusively with a single male, indicating that high levels of average kinship between group members are necessary for the evolution of reproductive altruism. In this paper, we show that in mammals, the evolution of cooperative breeding has been restricted to socially monogamous species which currently represent 5 per cent of all mammalian species. Since extra-pair paternity is relatively uncommon in socially monogamous and cooperatively breeding mammals, our analyses support the suggestion that high levels of average kinship between group members have played an important role in the evolution of cooperative breeding in non-human mammals, as well as in birds and insects. PMID:22279167

PARTIAL REPRODUCTIVE ISOLATION OF A RECENTLY DERIVED RESIDENT-FRESHWATER POPULATION OF THREESPINE STICKLEBACK (GASTEROSTEUS ACULEATUS) FROM ITS PUTATIVE ANADROMOUS ANCESTOR

PubMed Central

Furin, Christoff G.; Von Hippel, Frank A.; Bell, Michael A.

2012-01-01

We used no-choice mating trials to test for assortative mating between a newly derived resident-freshwater population (8 – 22 generations since founding) of threespine stickleback (Gasterosteus aculeatus) in Loberg Lake, Alaska and its putative anadromous ancestor as well as a morphologically convergent but distantly related resident-freshwater population. Partial reproductive isolation has evolved between the Loberg Lake population and its ancestor within a remarkably short time period. However, Loberg stickleback readily mate with morphologically similar, but distantly related resident-freshwater stickleback. Partial pre-mating isolation is asymmetrical; anadromous females and smaller, resident-freshwater males from Loberg Lake readily mate, but the anadromous males and smaller Loberg females do not. Our results indicate that pre-mating isolation can begin to evolve in allopatry within a few generations after isolation as a correlated effect of evolution of reduced body size. PMID:23025615

Comparative Genomics of the Mating-Type Loci of the Mushroom Flammulina velutipes Reveals Widespread Synteny and Recent Inversions

PubMed Central

van Peer, Arend F.; Park, Soon-Young; Shin, Pyung-Gyun; Jang, Kab-Yeul; Yoo, Young-Bok; Park, Young-Jin; Lee, Byoung-Moo; Sung, Gi-Ho; James, Timothy Y.; Kong, Won-Sik

2011-01-01

Background Mating-type loci of mushroom fungi contain master regulatory genes that control recognition between compatible nuclei, maintenance of compatible nuclei as heterokaryons, and fruiting body development. Regions near mating-type loci in fungi often show adapted recombination, facilitating the generation of novel mating types and reducing the production of self-compatible mating types. Compared to other fungi, mushroom fungi have complex mating-type systems, showing both loci with redundant function (subloci) and subloci with many alleles. The genomic organization of mating-type loci has been solved in very few mushroom species, which complicates proper interpretation of mating-type evolution and use of those genes in breeding programs. Methodology/Principal Findings We report a complete genetic structure of the mating-type loci from the tetrapolar, edible mushroom Flammulina velutipes mating type A3B3. Two matB3 subloci, matB3a that contains a unique pheromone and matB3b, were mapped 177 Kb apart on scaffold 1. The matA locus of F. velutipes contains three homeodomain genes distributed over 73 Kb distant matA3a and matA3b subloci. The conserved matA region in Agaricales approaches 350 Kb and contains conserved recombination hotspots showing major rearrangements in F. velutipes and Schizophyllum commune. Important evolutionary differences were indicated; separation of the matA subloci in F. velutipes was diverged from the Coprinopsis cinerea arrangement via two large inversions whereas separation in S. commune emerged through transposition of gene clusters. Conclusions/Significance In our study we determined that the Agaricales have very large scale synteny at matA (∼350 Kb) and that this synteny is maintained even when parts of this region are separated through chromosomal rearrangements. Four conserved recombination hotspots allow reshuffling of large fragments of this region. Next to this, it was revealed that large distance subloci can exist in matB as well. Finally, the genes that were linked to specific mating types will serve as molecular markers in breeding. PMID:21799803

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

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.

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.

Brain size evolution in pipefishes and seahorses: the role of feeding ecology, life history and sexual selection.

PubMed

Tsuboi, M; Lim, A C O; Ooi, B L; Yip, M Y; Chong, V C; Ahnesjö, I; Kolm, N

2017-01-01

Brain size varies greatly at all taxonomic levels. Feeding ecology, life history and sexual selection have been proposed as key components in generating contemporary diversity in brain size across vertebrates. Analyses of brain size evolution have, however, been limited to lineages where males predominantly compete for mating and females choose mates. Here, we present the first original data set of brain sizes in pipefishes and seahorses (Syngnathidae) a group in which intense female mating competition occurs in many species. After controlling for the effect of shared ancestry and overall body size, brain size was positively correlated with relative snout length. Moreover, we found that females, on average, had 4.3% heavier brains than males and that polyandrous species demonstrated more pronounced (11.7%) female-biased brain size dimorphism. Our results suggest that adaptations for feeding on mobile prey items and sexual selection in females are important factors in brain size evolution of pipefishes and seahorses. Most importantly, our study supports the idea that sexual selection plays a major role in brain size evolution, regardless of on which sex sexual selection acts stronger. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

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

Universality in a Neutral Evolution Model

NASA Astrophysics Data System (ADS)

King, Dawn; Scott, Adam; Maric, Nevena; Bahar, Sonya

2013-03-01

Agent-based models are ideal for investigating the complex problems of biodiversity and speciation because they allow for complex interactions between individuals and between individuals and the environment. Presented here is a ``null'' model that investigates three mating types - assortative, bacterial, and random - in phenotype space, as a function of the percentage of random death δ. Previous work has shown phase transition behavior in an assortative mating model with variable fitness landscapes as the maximum mutation size (μ) was varied (Dees and Bahar, 2010). Similarly, this behavior was recently presented in the work of Scott et al. (submitted), on a completely neutral landscape, for bacterial-like fission as well as for assortative mating. Here, in order to achieve an appropriate ``null'' hypothesis, the random death process was changed so each individual, in each generation, has the same probability of death. Results show a continuous nonequilibrium phase transition for the order parameters of the population size and the number of clusters (analogue of species) as δ is varied for three different mutation sizes of the system. The system shows increasing robustness as μ increases. Universality classes and percolation properties of this system are also explored. This research was supported by funding from: University of Missouri Research Board and James S. McDonnell Foundation

"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

The response to selection for broad male response to female sex pheromone and its implications for divergence in close-range mating behavior in the European corn borer moth, Ostrinia nubilalis.

PubMed

Droney, David C; Musto, Callie J; Mancuso, Katie; Roelofs, Wendell L; Linn, Charles E

2012-12-01

Coordinated sexual communication systems, seen in many species of moths, are hypothesized to be under strong stabilizing natural selection. Stabilized communication systems should be resistant to change, but there are examples of species/populations that show great diversification. A possible solution is that it is directional sexual selection on variation in male response that drives evolution. We tested a component of this model by asking whether 'rare' males (ca. 5 % of all males in a population) of the European corn borer moth (ECB), Ostrinia nubilalis, that respond to the sex pheromones of both ECB and a different Ostrinia species (O. furnacalis, the Asian corn borer, ACB), might play an important role in diversification. We specifically tested, via artificial selection, whether this broad male response has an evolvable genetic component. We increased the frequency of broad male response from 5 to 70 % in 19 generations, showing that broad-responding males could be important for the evolution of novel communication systems in ECB. We did not find a broader range of mating acceptance of broad males by females of the base population, however, suggesting that broad response would be unlikely to increase in frequency without the involvement of other factors. However, we found that ECB selection-line females accepted a broader range of courting males, including those of ACB, than did females of the base population. Thus, a genetic correlation exists between broad, long-range response to female sex pheromone and the breadth of female acceptance of males at close range. These results are discussed in the context of evolution of novel communication systems in Ostrinia.

Pair-bonding, romantic love, and evolution: the curious case of Homo sapiens.

PubMed

Fletcher, Garth J O; Simpson, Jeffry A; Campbell, Lorne; Overall, Nickola C

2015-01-01

This article evaluates a thesis containing three interconnected propositions. First, romantic love is a "commitment device" for motivating pair-bonding in humans. Second, pair-bonding facilitated the idiosyncratic life history of hominins, helping to provide the massive investment required to rear children. Third, managing long-term pair bonds (along with family relationships) facilitated the evolution of social intelligence and cooperative skills. We evaluate this thesis by integrating evidence from a broad range of scientific disciplines. First, consistent with the claim that romantic love is an evolved commitment device, our review suggests that it is universal; suppresses mate-search mechanisms; has specific behavioral, hormonal, and neuropsychological signatures; and is linked to better health and survival. Second, we consider challenges to this thesis posed by the existence of arranged marriage, polygyny, divorce, and infidelity. Third, we show how the intimate relationship mind seems to be built to regulate and monitor relationships. Fourth, we review comparative evidence concerning links among mating systems, reproductive biology, and brain size. Finally, we discuss evidence regarding the evolutionary timing of shifts to pair-bonding in hominins. We conclude there is interdisciplinary support for the claim that romantic love and pair-bonding, along with alloparenting, played critical roles in the evolution of Homo sapiens. © The Author(s) 2014.

Birds Do It, Bees Do It: Evolution and the Comparative Psychology of Mate Choice

ERIC Educational Resources Information Center

Boothroyd, Lynda G.; McLaughlin, Edward

2011-01-01

The primary theoretical framework for the study of human physical attraction is currently Darwinian sexual selection. Not only has this perspective enabled the discovery of what appear to be strong universals in human mate choice but it has also facilitated our understanding of systematic variation in preferences both between and within…

KSC-03PD-1094

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- Workers in the Multi-Payload Processing Facility close the fairing around the Galaxy Evolution Explorer (GALEX). The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

KSC-03PD-1043

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. - Workers in the Multi-Payload Processing Facility prepare the Galaxy Evolution Explorer (GALEX) for encapsulation. The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

KSC-03PD-1044

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- Workers in the Multi-Payload Processing Facility prepare the Galaxy Evolution Explorer (GALEX) for encapsulation. The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

Why do female Callosobruchus maculatus kick their mates?

PubMed

van Lieshout, Emile; McNamara, Kathryn B; Simmons, Leigh W

2014-01-01

Sexual conflict is now recognised as an important driver of sexual trait evolution. However, due to their variable outcomes and effects on other fitness components, the detection of sexual conflicts on individual traits can be complicated. This difficulty is exemplified in the beetle Callosobruchus maculatus, where longer matings increase the size of nutritious ejaculates but simultaneously reduce female future receptivity. While previous studies show that females gain direct benefits from extended mating duration, females show conspicuous copulatory kicking behaviour, apparently to dislodge mating males prematurely. We explore the potential for sexual conflict by comparing several fitness components and remating propensity in pairs of full sibling females where each female mated with a male from an unrelated pair of full sibling males. For one female, matings were terminated at the onset of kicking, whereas the other's matings remained uninterrupted. While fecundity (number of eggs) was similar between treatments, uninterrupted matings enhanced adult offspring numbers and fractionally also longevity. However, females whose matings were interrupted at the onset of kicking exhibited an increased propensity to remate. Since polyandry can benefit female fitness in this species, we argue that kicking, rather than being maladaptive, may indicate that females prefer remating over increased ejaculate size. It may thus be difficult to assess the presence of sexual conflict over contested traits such as mating duration when females face a trade off between direct benefits gained from one mating and indirect benefits from additional matings.

Evolution of the IBDM Structural Latch Development into a Generic Simplified Design

NASA Technical Reports Server (NTRS)

DeVriendt, K.; Dittmer, H.; Vrancken, D.; Urmston, P.; Gracia, O.

2010-01-01

This paper presents the evolution in the development of the structural latch for the International Berthing Docking Mechanism (IBDM, see Figure 1). It reports on the lessons learned since completion of the test program on the engineering development unit of the first generation latching system in 2007. The initial latch design has been through a second generation concept in 2008, and now evolved into a third generation of this mechanism. Functional and structural testing on the latest latch hardware has recently been completed with good results. The IBDM latching system will provide the structural connection between two mated space vehicles after berthing or docking. The mechanism guarantees that the interface seals become compressed to form a leak-tight pressure system that creates a passageway for the astronauts.

Synergy from reproductive division of labor and genetic complexity drive the evolution of sex.

PubMed

Jaffe, Klaus

2018-04-16

Computer experiments that mirror the evolutionary dynamics of sexual and asexual organisms as they occur in nature were used to test features proposed to explain the evolution of sexual recombination. Results show that this evolution is better described as a network of interactions between possible sexual forms, including diploidy, thelytoky, facultative sex, assortation, bisexuality, and division of labor between the sexes, rather than a simple transition from parthenogenesis to sexual recombination. Diploidy was shown to be fundamental for the evolution of sex; bisexual reproduction emerged only among anisogamic diploids with a synergistic division of reproductive labor; and facultative sex was more likely to evolve among haploids practicing assortative mating. Looking at the evolution of sex as a complex system through individual-based simulations explains better the diversity of sexual strategies known to exist in nature, compared to classical analytical models.

Real-time divergent evolution in plants driven by pollinators

PubMed Central

Gervasi, Daniel D. L.; Schiestl, Florian P

2017-01-01

Pollinator-driven diversification is thought to be a major source of floral variation in plants. Our knowledge of this process is, however, limited to indirect assessments of evolutionary changes. Here, we employ experimental evolution with fast cycling Brassica rapa plants to demonstrate adaptive evolution driven by different pollinators. Our study shows pollinator-driven divergent selection as well as divergent evolution in plant traits. Plants pollinated by bumblebees evolved taller size and more fragrant flowers with increased ultraviolet reflection. Bumblebees preferred bumblebee-pollinated plants over hoverfly-pollinated plants at the end of the experiment, showing that plants had adapted to the bumblebees' preferences. Plants with hoverfly pollination became shorter, had reduced emission of some floral volatiles, but increased fitness through augmented autonomous self-pollination. Our study demonstrates that changes in pollinator communities can have rapid consequences on the evolution of plant traits and mating system. PMID:28291771

The Development and Validation of the Measure of Acceptance of the Theory of Evolution Instrument.

ERIC Educational Resources Information Center

Rutledge, Michael L.; Warden, Melissa A.

1999-01-01

Describes the development and validation of the Measure of Acceptance of the Theory of Evolution (MATE), a 20-item, Likert-scaled instrument that assesses teachers' overall acceptance of evolutionary theory. (Author/CCM)

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.

Correlated evolution between male ejaculate allocation and female remating behaviour in seed beetles (Bruchidae).

PubMed

Katvala, M; Rönn, J L; Arnqvist, G

2008-03-01

Sperm competition theory suggests that female remating rate determines the selective regime that dictates the evolution of male ejaculate allocation. To test for correlated evolution between female remating behaviour and male ejaculate traits, we subjected detailed experimental data on female and male reproductive traits in seven-seed beetle species to phylogenetic comparative analyses. The evolution of a larger first ejaculate was positively correlated with the evolution of a more rapid decline in ejaculate size over successive matings. Further, as predicted by theory, an increase in female remating rate correlated with the evolution of larger male testes but smaller ejaculates. However, an increase in female remating was associated with the evolution of a less even allocation of ejaculate resources over successive matings, contrary to classic sperm competition theory. We failed to find any evidence for coevolution between the pattern of male ejaculate allocation and variation in female quality and we conclude that some patterns of correlated evolution are congruent with current theory, whereas some are not. We suggest that this may reflect the fact that much sperm competition theory does not fully incorporate other factors that may affect the evolution of male and female traits, such as trade-offs between ejaculate expenditure and other competing demands and the evolution of resource acquisition.

Low-Impact Mating System for Docking Spacecraft

NASA Technical Reports Server (NTRS)

Lewis, James L.; Robertson, Brandan; Carroll, Monty B.; Le, Thang; Morales, Ray

2008-01-01

A document describes a low-impact mating system suitable for both docking (mating of two free-flying spacecraft) and berthing (in which a robot arm in one spacecraft positions an object for mating with either spacecraft). The low-impact mating system is fully androgynous: it mates with a copy of itself, i.e., all spacecraft and other objects to be mated are to be equipped with identical copies of the system. This aspect of the design helps to minimize the number of unique parts and to standardize and facilitate mating operations. The system includes a closed-loop feedback control subsystem that actively accommodates misalignments between mating spacecraft, thereby attenuating spacecraft dynamics and mitigating the need for precise advance positioning of the spacecraft. The operational characteristics of the mating system can be easily configured in software, during operation, to enable mating of spacecraft having various masses, center-of-gravity offsets, and closing velocities. The system design provides multi-fault tolerance for critical operations: for example, to ensure unmating at a critical time, a redundant unlatching mechanism and two independent pyrotechnic release subsystems are included.

Mating behavior and the evolution of sperm design

PubMed Central

Schärer, Lukas; Littlewood, D. Timothy J.; Waeschenbach, Andrea; Yoshida, Wataru; Vizoso, Dita B.

2011-01-01

Sperm are the most diverse of all animal cell types, and much of the diversity in sperm design is thought to reflect adaptations to the highly variable conditions under which sperm function and compete to achieve fertilization. Recent work has shown that these conditions often evolve rapidly as a consequence of multiple mating, suggesting a role for sexual selection and sexual conflict in the evolution of sperm design. However, very little of the striking diversity in sperm design is understood functionally, particularly in internally fertilizing organisms. We use phylogenetic comparative analyses covering 16 species of the hermaphroditic flatworm genus Macrostomum to show that a complex sperm design is associated with reciprocal mating and that this complexity is lost secondarily when hypodermic insemination—sperm injection through the epidermis—evolves. Specifically, the complex sperm design, which includes stiff lateral bristles, is likely a male persistence trait associated with sexual conflicts over the fate of received ejaculates and linked to female resistance traits, namely an intriguing postcopulatory sucking behavior and a thickened epithelium of the sperm-receiving organ. Our results suggest that the interactions between sperm donor, sperm, and sperm recipient can change drastically when hypodermic insemination evolves, involving convergent evolution of a needle-like copulatory organ, a simpler sperm design, and a simpler female genital morphology. Our study documents that a shift in the mating behavior may alter fundamentally the conditions under which sperm compete and thereby lead to a drastic change in sperm design. PMID:21220334

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.

KSC-03PD-1091

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- Workers in the Multi-Payload Processing Facility maneuver the port fairing into place around the Galaxy Evolution Explorer (GALEX). The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

KSC-03PD-1092

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- Workers in the Multi-Payload Processing Facility maneuver the port fairing into place around the Galaxy Evolution Explorer (GALEX). The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

KSC-03PD-1048

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- Workers watch as the first part of the fairing closes in on the Galaxy Evolution Explorer (GALEX) for encapsulation. The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined. .

KSC-03PD-1088

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- Workers in the Multi-Payload Processing Facility prepare to install the port fairing on the Galaxy Evolution Explorer (GALEX). The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

KSC-03PD-1089

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- -- Workers in the Multi-Payload Processing Facility prepare to install the port fairing on the Galaxy Evolution Explorer (GALEX). The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

KSC-03PD-1087

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. - Workers in the Multi-Payload Processing Facility prepare to install the port fairing on the Galaxy Evolution Explorer (GALEX). The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

Climate change alters reproductive isolation and potential gene flow in an annual plant.

PubMed

Franks, Steven J; Weis, Arthur E

2009-11-01

Climate change will likely cause evolution due not only to selection but also to changes in reproductive isolation within and among populations. We examined the effects of a natural drought on the timing of flowering in two populations of Brassica rapa and the consequences for predicted reproductive isolation and potential gene flow. Seeds were collected before and after a 5-year drought in southern California from two populations varying in soil moisture. Lines derived from these seeds were raised in the greenhouse under wet and drought conditions. We found that the natural drought caused changes in reproductive timing and that the changes were greater for plants from the wet than from the dry site. This differential shift caused the populations to become more phenological similar, which should lead to less reproductive isolation and increased gene flow. We estimated a high level of assortative mating by flowering time, which potentially contributed to the rapid evolution of phenological traits following the drought. Estimates of assortative mating were higher for the wet site population, and assortative mating was reduced following the drought. This study shows that climate change can potentially alter gene flow and reproductive isolation within and among populations, strongly influencing evolution.

The sexual selection paradigm: have we overlooked other mechanisms in the evolution of male ornaments?

PubMed

Candolin, Ulrika; Tukiainen, Iina

2015-10-07

Extravagant male ornaments expressed during reproduction are almost invariably assumed to be sexually selected and evolve through competition for mating opportunities. Yet in species where male reproductive success depends on the defence of offspring, male ornaments could also evolve through social competition for offspring survival. However, in contrast to female ornaments, this possibility has received little attention in males. We show that a male ornament that is traditionally assumed to be sexually selected--the red nuptial coloration of the three-spined stickleback--is under stronger selection for offspring survival than for mating success. Males express most coloration during parenting, when they no longer attract females, and the colour correlates with nest retention and hatching success but not with attractiveness to females. This contradicts earlier assumptions and suggests that social selection for offspring survival rather than for sexual selection for mating success is the main mechanism maintaining the ornament in the population. These results suggest that we should consider other forms of social selection beyond sexual selection when seeking to explain the function and evolution of male ornaments. An incorrect assignment of selection pressures could hamper our understanding of evolution. © 2015 The Author(s).

Low-impact mating system

NASA Technical Reports Server (NTRS)

Lewis, James L. (Inventor); Carroll, Monty B. (Inventor); Le, Thang D. (Inventor); Morales, Ray H. (Inventor); Robertson, Brandan R. (Inventor)

2009-01-01

An androgynous mating system for mating two exoatmospheric space modules comprising a first mating assembly capable of mating with a second mating assembly; a second mating assembly structurally identical to said first mating assembly, said first mating assembly comprising; a load ring; a plurality of load cell subassemblies; a plurality of actuators; a base ring; a tunnel; a closed loop control system; one or more electromagnets; and one or more striker plates, wherein said one or more electomagnets on said second mating assembly are capable of mating with said one or more striker plates on said first mating assembly, and wherein said one or more striker plates is comprised of a plate of predetermined shape and a 5-DOF mechanism capable of maintaining predetermined contact requirements during said mating of said one or more electromagnets and said one or more striker plates.

VARIATION AND EVOLUTION OF BREEDING SYSTEMS IN THE TURNERA ULMIFOLIA L. COMPLEX (TURNERACEAE).

PubMed

Barrett, Spencer C H; Shore, Joel S

1987-03-01

The evolutionary and functional relationships among breeding systems and floral morphology were investigated in the Turnera ulmifolia complex. Predictions of a model of breeding system evolution among distylous and homostylous varieties were tested. Chromosome counts of 73 accessions revealed an association between breeding system and chromosome number. Diploid and tetraploid populations of five taxonomic varieties are distylous and self-incompatible, whereas hexaploid populations of three varieties are homostylous and self-compatible. The latter occur at different margins of the geographical range of the complex. Crossing studies and analyses of pollen and ovule fertility in F 1 's revealed that the three homostylous varieties are intersterile. To test the prediction that, homostylous varieties are long homostyles that have originated by crossing over within the distyly supergene, a crossing program was undertaken among distylous and homostylous plants. Residual incompatibility was observed in styles and pollen of each homostylous variety with patterns consistent with predictions of the cross-over model. The intersterility of hexaploid varieties suggests that long homostyly has arisen on at least three occasions in the complex by recombination within the supergene controlling distyly. Deviation from expected compatibility behavior occurs in populations of var. angustifolia that have the longest styles. These phenotypes displayed the greatest separation between anthers and stigmas (herkogamy) and set little seed in crosses with long- or short-styled plants. This suggests that they are derived from long homostyles with shorter length styles. It is proposed that selection for increased outcrossing has favored the evolution of herkogamy in long homostyles. Estimates of outcrossing rate in a distylous population using allozyme markers confirmed that dimorphic incompatibility enforces complete outcrossing. Significant genetic variation for floral traits likely to influence the mating system, such as stigma-anther separation, occurs within and among homostylous populations of var. angustifolia on Jamaica. Estimates of the mating system of families from a population with varying degrees of stigma-anther separation, using five isozyme loci, were heterogeneous and ranged from t = 0.04-0.79. Families exhibiting the largest mean stigma-anther separation have higher outcrossing rates than those with little separation. © 1987 The Society for the Study of Evolution.

From kissing to belly stridulation: comparative analysis reveals surprising diversity, rapid evolution, and much homoplasy in the mating behaviour of 27 species of sepsid flies (Diptera: Sepsidae).

PubMed

Puniamoorthy, N; Ismail, M R B; Tan, D S H; Meier, R

2009-11-01

Our understanding of how fast mating behaviour evolves in insects is rather poor due to a lack of comparative studies among insect groups for which phylogenetic relationships are known. Here, we present a detailed study of the mating behaviour of 27 species of Sepsidae (Diptera) for which a well-resolved and supported phylogeny is available. We demonstrate that mating behaviour is extremely diverse in sepsids with each species having its own mating profile. We define 32 behavioural characters and document them with video clips. Based on sister species comparisons, we provide several examples where mating behaviour evolves faster than all sexually dimorphic morphological traits. Mapping the behaviours onto the molecular tree reveals much homoplasy, comparable to that observed for third positions of mitochondrial protein-encoding genes. A partitioned Bremer support (PBS) analysis reveals conflict between the molecular and behavioural data, but behavioural characters have higher PBS values per parsimony-informative character than DNA sequence characters.

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.

Two HAP2-GCS1 homologs responsible for gamete interactions in the cellular slime mold with multiple mating types: Implication for common mechanisms of sexual reproduction shared by plants and protozoa and for male-female differentiation.

PubMed

Okamoto, Marina; Yamada, Lixy; Fujisaki, Yukie; Bloomfield, Gareth; Yoshida, Kentaro; Kuwayama, Hidekazu; Sawada, Hitoshi; Mori, Toshiyuki; Urushihara, Hideko

2016-07-01

Fertilization is a central event in sexual reproduction, and understanding its molecular mechanisms has both basic and applicative biological importance. Recent studies have uncovered the molecules that mediate this process in a variety of organisms, making it intriguing to consider conservation and evolution of the mechanisms of sexual reproduction across phyla. The social amoeba Dictyostelium discoideum undergoes sexual maturation and forms gametes under dark and humid conditions. It exhibits three mating types, type-I, -II, and -III, for the heterothallic mating system. Based on proteome analyses of the gamete membranes, we detected expression of two homologs of the plant fertilization protein HAP2-GCS1. When their coding genes were disrupted in type-I and type-II strains, sexual potency was completely lost, whereas disruption in the type-III strain did not affect mating behavior, suggesting that the latter acts as female in complex organisms. Our results demonstrate the highly conserved function of HAP2-GCS1 in gamete interactions and suggest the presence of additional allo-recognition mechanisms in D. discoideum gametes. Copyright © 2016 Elsevier Inc. All rights reserved.

Why Do Female Callosobruchus maculatus Kick Their Mates?

PubMed Central

van Lieshout, Emile; McNamara, Kathryn B.; Simmons, Leigh W.

2014-01-01

Sexual conflict is now recognised as an important driver of sexual trait evolution. However, due to their variable outcomes and effects on other fitness components, the detection of sexual conflicts on individual traits can be complicated. This difficulty is exemplified in the beetle Callosobruchus maculatus, where longer matings increase the size of nutritious ejaculates but simultaneously reduce female future receptivity. While previous studies show that females gain direct benefits from extended mating duration, females show conspicuous copulatory kicking behaviour, apparently to dislodge mating males prematurely. We explore the potential for sexual conflict by comparing several fitness components and remating propensity in pairs of full sibling females where each female mated with a male from an unrelated pair of full sibling males. For one female, matings were terminated at the onset of kicking, whereas the other’s matings remained uninterrupted. While fecundity (number of eggs) was similar between treatments, uninterrupted matings enhanced adult offspring numbers and fractionally also longevity. However, females whose matings were interrupted at the onset of kicking exhibited an increased propensity to remate. Since polyandry can benefit female fitness in this species, we argue that kicking, rather than being maladaptive, may indicate that females prefer remating over increased ejaculate size. It may thus be difficult to assess the presence of sexual conflict over contested traits such as mating duration when females face a trade off between direct benefits gained from one mating and indirect benefits from additional matings. PMID:24752530

Discovery of a modified tetrapolar sexual cycle in Cryptococcus amylolentus and the evolution of MAT in the Cryptococcus species complex.

PubMed

Findley, Keisha; Sun, Sheng; Fraser, James A; Hsueh, Yen-Ping; Averette, Anna Floyd; Li, Wenjun; Dietrich, Fred S; Heitman, Joseph

2012-01-01

Sexual reproduction in fungi is governed by a specialized genomic region called the mating-type locus (MAT). The human fungal pathogenic and basidiomycetous yeast Cryptococcus neoformans has evolved a bipolar mating system (a, α) in which the MAT locus is unusually large (>100 kb) and encodes >20 genes including homeodomain (HD) and pheromone/receptor (P/R) genes. To understand how this unique bipolar mating system evolved, we investigated MAT in the closely related species Tsuchiyaea wingfieldii and Cryptococcus amylolentus and discovered two physically unlinked loci encoding the HD and P/R genes. Interestingly, the HD (B) locus sex-specific region is restricted (∼2 kb) and encodes two linked and divergently oriented homeodomain genes in contrast to the solo HD genes (SXI1α, SXI2a) of C. neoformans and Cryptococcus gattii. The P/R (A) locus contains the pheromone and pheromone receptor genes but has expanded considerably compared to other outgroup species (Cryptococcus heveanensis) and is linked to many of the genes also found in the MAT locus of the pathogenic Cryptococcus species. Our discovery of a heterothallic sexual cycle for C. amylolentus allowed us to establish the biological roles of the sex-determining regions. Matings between two strains of opposite mating-types (A1B1×A2B2) produced dikaryotic hyphae with fused clamp connections, basidia, and basidiospores. Genotyping progeny using markers linked and unlinked to MAT revealed that meiosis and uniparental mitochondrial inheritance occur during the sexual cycle of C. amylolentus. The sexual cycle is tetrapolar and produces fertile progeny of four mating-types (A1B1, A1B2, A2B1, and A2B2), but a high proportion of progeny are infertile, and fertility is biased towards one parental mating-type (A1B1). Our studies reveal insights into the plasticity and transitions in both mechanisms of sex determination (bipolar versus tetrapolar) and sexual reproduction (outcrossing versus inbreeding) with implications for similar evolutionary transitions and processes in fungi, plants, and animals.

KSC-99pp0653

NASA Image and Video Library

1999-06-04

At Launch Pad 17A, Cape Canaveral Air Station (CCAS), the launch tower again encircles the Boeing Delta II rocket after being mated with its solid rocket boosters. The rocket is targeted to launch NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) on June 23 at CCAS. Developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., FUSE will investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum

KSC-99pp0649

NASA Image and Video Library

1999-06-04

A solid rocket booster arrives at Launch Pad 17A, Cape Canaveral Air Station (CCAS), where it will be mated with the Boeing Delta II rocket in the background. The rocket is targeted to launch NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) on June 23 at CCAS. Developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., FUSE will investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum

KSC-99pp0651

NASA Image and Video Library

1999-06-04

Two solid rocket boosters are lifted up the tower on Launch Pad 17A, Cape Canaveral Air Station (CCAS), to be mated with a Boeing Delta II rocket. The rocket is targeted to launch NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) on June 23 at CCAS. Developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., FUSE will investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum

KSC-99pp0652

NASA Image and Video Library

1999-06-04

At Launch Pad 17A, Cape Canaveral Air Station (CCAS), workers check the solid rocket boosters overhead being mated with the Boeing Delta II rocket already in place. The rocket is targeted to launch NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) on June 23 at CCAS. Developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., FUSE will investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum

KSC-99pp0650

NASA Image and Video Library

1999-06-04

A Boeing Delta II rocket sits on Launch Pad 17A, Cape Canaveral Air Station (CCAS), waiting to be mated with its solid rocket boosters. The rocket is targeted to launch NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) on June 23 at CCAS. Developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., FUSE will investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum

A sex-specific trade-off between mating preferences for genetic compatibility and body size in a cichlid fish with mutual mate choice.

PubMed

Thünken, Timo; Meuthen, Denis; Bakker, Theo C M; Baldauf, Sebastian A

2012-08-07

Mating preferences for genetic compatibility strictly depend on the interplay of the genotypes of potential partners and are therein fundamentally different from directional preferences for ornamental secondary sexual traits. Thus, the most compatible partner is on average not the one with most pronounced ornaments and vice versa. Hence, mating preferences may often conflict. Here, we present a solution to this problem while investigating the interplay of mating preferences for relatedness (a compatibility criterion) and large body size (an ornamental or quality trait). In previous experiments, both sexes of Pelvicachromis taeniatus, a cichlid fish with mutual mate choice, showed preferences for kin and large partners when these criteria were tested separately. In the present study, test fish were given a conflicting choice between two potential mating partners differing in relatedness as well as in body size in such a way that preferences for both criteria could not simultaneously be satisfied. We show that a sex-specific trade-off occurs between mating preferences for body size and relatedness. For females, relatedness gained greater importance than body size, whereas the opposite was true for males. We discuss the potential role of the interplay between mating preferences for relatedness and body size for the evolution of inbreeding preference.

A sex-specific trade-off between mating preferences for genetic compatibility and body size in a cichlid fish with mutual mate choice

PubMed Central

Thünken, Timo; Meuthen, Denis; Bakker, Theo C. M.; Baldauf, Sebastian A.

2012-01-01

Mating preferences for genetic compatibility strictly depend on the interplay of the genotypes of potential partners and are therein fundamentally different from directional preferences for ornamental secondary sexual traits. Thus, the most compatible partner is on average not the one with most pronounced ornaments and vice versa. Hence, mating preferences may often conflict. Here, we present a solution to this problem while investigating the interplay of mating preferences for relatedness (a compatibility criterion) and large body size (an ornamental or quality trait). In previous experiments, both sexes of Pelvicachromis taeniatus, a cichlid fish with mutual mate choice, showed preferences for kin and large partners when these criteria were tested separately. In the present study, test fish were given a conflicting choice between two potential mating partners differing in relatedness as well as in body size in such a way that preferences for both criteria could not simultaneously be satisfied. We show that a sex-specific trade-off occurs between mating preferences for body size and relatedness. For females, relatedness gained greater importance than body size, whereas the opposite was true for males. We discuss the potential role of the interplay between mating preferences for relatedness and body size for the evolution of inbreeding preference. PMID:22513859

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

Within-season variability of fighting behaviour in an Australian alpine grasshopper

PubMed Central

Muschett, Giselle; Umbers, Kate D. L.; Herberstein, Marie E.

2017-01-01

Throughout the breeding season, changing environmental and biological conditions can lead to variation in the reproductive landscape of many species. In alpine environments temperature is a key driver of behaviour for small ectotherms such as insects, but variable biotic factors such as mate quality and availability can also influence behaviour. Kosicuscola tristis is a small semelparous grasshopper of the Australian alpine region. In a rare behaviour among grasshoppers, K. tristis males engage in vigorous fights over access to females, involving mandible displays, kicking, biting and grappling. In this study we describe the variation in fighting behaviour of K. tristis throughout the breeding season and test several hypotheses related to temperature, body size, mating behaviour, and female quality. We show that K. tristis males are more aggressive toward each other at the end of the breeding season than at the beginning. This increased aggression is associated with decreased daily average temperatures (from ~20°C to ~9°C), decreased mating activity, increased female fecundity, and an unexpected trend toward an increase in female-to-male aggression. These results suggest that K. tristis is likely under increased selective pressure to time key life cycle events with favourable biological and climatic conditions. The stochastic nature of alpine environments combined with a relatively short life span and breeding season, as well as limited mating opportunities toward the end of the season may have contributed to the evolution of this extraordinary mating system. PMID:28403243

Genotype-by-Environment Interactions for Female Mate Choice of Male Cuticular Hydrocarbons in Drosophila simulans

PubMed Central

Ingleby, Fiona C.; Hunt, John; Hosken, David J.

2013-01-01

Recent research has highlighted the potential importance of environmental and genotype-by-environment (G×E) variation in sexual selection, but most studies have focussed on the expression of male sexual traits. Consequently, our understanding of genetic variation for plasticity in female mate choice is extremely poor. In this study we examine the genetics of female mate choice in Drosophila simulans using isolines reared across two post-eclosion temperatures. There was evidence for G×Es in female choosiness and preference, which suggests that the evolution of female mate choice behaviour could differ across environments. However, the ranked order of preferred males was consistent across females and environments, so the same males are favoured by mate choice in spite of G×Es. Our study highlights the importance of taking cross-environment perspectives in order to gain a more comprehensive understanding of the operation of sexual selection. PMID:23825675

Monogamy in the maternally mouthbrooding Lake Tanganyika cichlid fish Tropheus moorii

PubMed Central

Egger, Bernd; Obermüller, Beate; Phiri, Harris; Sturmbauer, Christian; Sefc, Kristina M

2006-01-01

Supported by evidence for assortative mating and polygynandry, sexual selection through mate choice was suggested as the main force driving the evolution of colour diversity of haplochromine cichlids in Lakes Malawi and Victoria. The phylogenetically closely related tribe Tropheini of Lake Tanganyika includes the genus Tropheus, which comprises over 100 colour variants currently classified into six morphologically similar, polyphyletic species. To assess the potential for sexual selection in this sexually monochromatic maternal mouthbrooder, we used microsatellite-based paternity inference to investigate the mating system of Tropheus moorii. In contrast to haplochromines in Lake Malawi, multiple paternity is rare or even absent in broods of T. moorii. Eighteen of the 19 analysed families were consistent with genetic monogamy, while either a mutation or more than one sire explained the genotype of one offspring in another brood. We discuss the differences in breeding behaviour between T. moorii and the Lake Malawi haplochromines, and evaluate additional factors or alternatives to sexual selection as promoters of colour diversification. A preliminary survey of other Tropheini species suggested that multiple paternity is infrequent in the entire tribe. PMID:16790413

Flash signal evolution in Photinus fireflies: character displacement and signal exploitation in a visual communication system.

PubMed

Stanger-Hall, Kathrin F; Lloyd, James E

2015-03-01

Animal communication is an intriguing topic in evolutionary biology. In this comprehensive study of visual signal evolution, we used a phylogenetic approach to study the evolution of the flash communication system of North American fireflies. The North American firefly genus Photinus contains 35 described species with simple ON-OFF visual signals, and information on habitat types, sympatric congeners, and predators. This makes them an ideal study system to test hypotheses on the evolution of male and female visual signal traits. Our analysis of 34 Photinus species suggests two temporal pattern generators: one for flash duration and one for flash intervals. Reproductive character displacement was a main factor for signal divergence in male flash duration among sympatric Photinus species. Male flash pattern intervals (i.e., the duration of the dark periods between signals) were positively correlated with the number of sympatric Photuris fireflies, which include predators of Photinus. Females of different Photinus species differ in their response preferences to male traits. As in other communication systems, firefly male sexual signals seem to be a compromise between optimizing mating success (sexual selection) and minimizing predation risk (natural selection). An integrative model for Photinus signal evolution is proposed. © 2015 The Author(s).

A Z-linked sterility locus causes sexual abstinence in hybrid females and facilitates speciation in Spodoptera frugiperda.

PubMed

Kost, Silvia; Heckel, David G; Yoshido, Atsuo; Marec, František; Groot, Astrid T

2016-06-01

In the fall armyworm, Spodoptera frugiperda (Lepidoptera, Noctuidae), two sympatric strains have been recognized that have been termed corn strain (C) and rice strain (R), referring to their most common host plants. Both strains are reproductively isolated via a distinct prezygotic barrier as well as via an intriguing postzygotic phenomenon: when R females have mated with C males, the resulting RC hybrid females exhibit dramatically reduced fertility independent of their mating partner. Here, we demonstrate that the reduced fertility is caused by the fact that these females refrain from mating, that is, females are behaviorally sterile. We identified a Z-chromosomally linked sterility locus that is most likely incompatible with yet to be identified autosomal (or cytoplasmic) factors, leading to the observed sexual abstinence. Within-chromosome mapping revealed the sterility locus to be located in an area of strongly reduced interstrain recombination. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Evolution of sociality in spiders leads to depleted genomic diversity at both population and species levels.

PubMed

Settepani, V; Schou, M F; Greve, M; Grinsted, L; Bechsgaard, J; Bilde, T

2017-08-01

Across several animal taxa, the evolution of sociality involves a suite of characteristics, a "social syndrome," that includes cooperative breeding, reproductive skew, primary female-biased sex ratio, and the transition from outcrossing to inbreeding mating system, factors that are expected to reduce effective population size (Ne). This social syndrome may be favoured by short-term benefits but come with long-term costs, because the reduction in Ne amplifies loss of genetic diversity by genetic drift, ultimately restricting the potential of populations to respond to environmental change. To investigate the consequences of this social life form on genetic diversity, we used a comparative RAD-sequencing approach to estimate genomewide diversity in spider species that differ in level of sociality, reproductive skew and mating system. We analysed multiple populations of three independent sister-species pairs of social inbreeding and subsocial outcrossing Stegodyphus spiders, and a subsocial outgroup. Heterozygosity and within-population diversity were sixfold to 10-fold lower in social compared to subsocial species, and demographic modelling revealed a tenfold reduction in Ne of social populations. Species-wide genetic diversity depends on population divergence and the viability of genetic lineages. Population genomic patterns were consistent with high lineage turnover, which homogenizes the genetic structure that builds up between inbreeding populations, ultimately depleting genetic diversity at the species level. Indeed, species-wide genetic diversity of social species was 5-8 times lower than that of subsocial species. The repeated evolution of species with this social syndrome is associated with severe loss of genomewide diversity, likely to limit their evolutionary potential. © 2017 John Wiley & Sons Ltd.

Cis-Regulatory Changes Associated with a Recent Mating System Shift and Floral Adaptation in Capsella

PubMed Central

Steige, Kim A.; Reimegård, Johan; Koenig, Daniel; Scofield, Douglas G.; Slotte, Tanja

2015-01-01

The selfing syndrome constitutes a suite of floral and reproductive trait changes that have evolved repeatedly across many evolutionary lineages in response to the shift to selfing. Convergent evolution of the selfing syndrome suggests that these changes are adaptive, yet our understanding of the detailed molecular genetic basis of the selfing syndrome remains limited. Here, we investigate the role of cis-regulatory changes during the recent evolution of the selfing syndrome in Capsella rubella, which split from the outcrosser Capsella grandiflora less than 200 ka. We assess allele-specific expression (ASE) in leaves and flower buds at a total of 18,452 genes in three interspecific F1 C. grandiflora x C. rubella hybrids. Using a hierarchical Bayesian approach that accounts for technical variation using genomic reads, we find evidence for extensive cis-regulatory changes. On average, 44% of the assayed genes show evidence of ASE; however, only 6% show strong allelic expression biases. Flower buds, but not leaves, show an enrichment of cis-regulatory changes in genomic regions responsible for floral and reproductive trait divergence between C. rubella and C. grandiflora. We further detected an excess of heterozygous transposable element (TE) insertions near genes with ASE, and TE insertions targeted by uniquely mapping 24-nt small RNAs were associated with reduced expression of nearby genes. Our results suggest that cis-regulatory changes have been important during the recent adaptive floral evolution in Capsella and that differences in TE dynamics between selfing and outcrossing species could be important for rapid regulatory divergence in association with mating system shifts. PMID:26318184

Male dimorphism and alternative reproductive tactics in harvestmen (Arachnida: Opiliones).

PubMed

Buzatto, Bruno A; Machado, Glauco

2014-11-01

Strong sexual selection may lead small males or males in poor condition to adopt alternative reproductive tactics (ARTs) as a way to avoid the risk of being completely excluded from the mating pool. ARTs, sometimes accompanying morphological dimorphism among males, are taxonomically widespread, especially common in arthropods. Here we review the current knowledge on ARTs and male dimorphism in a diverse but relatively overlooked group of arachnids, the order Opiliones, popularly known as harvestmen or daddy long-legs. We begin with a summary of harvestman mating systems, followed by a review of the two lines of evidence for the presence of ARTs in the group: (1) morphological data from natural populations and museum collections; and (2) behavioral information from field studies. Despite receiving less attention than spiders, scorpions and insects, our review shows that harvestmen are an exciting group of organisms that are potentially great models for sexual selection studies focused on ARTs. We also suggest that investigating the proximate mechanisms underlying male dimorphism in the order would be especially important. New research on ARTs and male dimorphism will have implications for our understanding of the evolution of mating systems, sperm competition, and polyandry. This article is part of a Special Issue entitled: Neotropical Behaviour. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

The effects of rival seminal plasma on sperm velocity in the alternative reproductive tactics of Chinook salmon.

PubMed

Lewis, Jason A; Pitcher, Trevor E

2017-04-01

Sperm competition is prevalent and intense in many animal mating systems, and is a major force driving evolution of such mating systems. The objective of this study was to determine the effect of seminal plasma on sperm velocity of male Chinook salmon (Onchorhynchus tshawytscha), which possesses a mating system with male alternative reproductive tactics and intense sperm competition. Male Chinook salmon either adopt a small, precocious sneaking tactic (jack) or a large, dominant tactic (hooknose). To test whether the seminal plasma can effect sperm velocity amongst sperm competitors, two experiments were done whereby males were paired based upon the alternative tactic each male adopted, with the first experiment consisting of jack-hooknose pairs (N = 16) and the second experiment consisting of jack-jack and hooknose-hooknose pairs (N = 12 and 14, respectively). Within each pair, milt of each male was manipulated such that seminal plasma was removed and swapped between the males in each pair and sperm velocity was measured. Jack seminal plasma caused a significant decrease (∼11.9%) in hooknose sperm velocity while causing a significant increase in jack sperm velocity (∼7%), while alternatively, hooknose seminal plasma had no affect on sperm velocity of jack or other hooknose males. This study shows that rival seminal plasma may affect the outcome of sperm competition between males; males adopting a sneaking tactic, that spawn in a disadvantageous mating position, may be able to compensate for this deficit by being more competitive through the effects of their seminal plasma on their competitor's sperm velocity. Copyright © 2016. Published by Elsevier Inc.

Roles of Female and Male Genotype in Post-Mating Responses in Drosophila melanogaster.

PubMed

Delbare, Sofie Y N; Chow, Clement Y; Wolfner, Mariana F; Clark, Andrew G

2017-10-30

Mating induces a multitude of changes in female behavior, physiology, and gene expression. Interactions between female and male genotype lead to variation in post-mating phenotypes and reproductive success. So far, few female molecules responsible for these interactions have been identified. Here, we used Drosophila melanogaster from 5 geographically dispersed populations to investigate such female × male genotypic interactions at the female transcriptomic and phenotypic levels. Females from each line were singly-mated to males from the same 5 lines, for a total of 25 combinations. Reproductive output and refractoriness to re-mating were assayed in females from the 25 mating combinations. Female × male genotypic interactions resulted in significant differences in these post-mating phenotypes. To assess whether female × male genotypic interactions affect the female post-mating transcriptome, next-generation RNA sequencing was performed on virgin and mated females at 5 to 6 h post-mating. Seventy-seven genes showed strong variation in mating-induced expression changes in a female × male genotype-dependent manner. These genes were enriched for immune response and odorant-binding functions, and for expression exclusively in the head. Strikingly, variation in post-mating transcript levels of a gene encoding a spermathecal endopeptidase was correlated with short-term egg production. The transcriptional variation found in specific functional classes of genes might be a read-out of female × male compatibility at a molecular level. Understanding the roles these genes play in the female post-mating response will be crucial to better understand the evolution of post-mating responses and related conflicts between the sexes. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Genome-Wide Responses of Female Fruit Flies Subjected to Divergent Mating Regimes

PubMed Central

Gerrard, Dave T.; Fricke, Claudia; Edward, Dominic A.; Edwards, Dylan R.; Chapman, Tracey

2013-01-01

Elevated rates of mating and reproduction cause decreased female survival and lifetime reproductive success across a wide range of taxa from flies to humans. These costs are fundamentally important to the evolution of life histories. Here we investigate the potential mechanistic basis of this classic life history component. We conducted 4 independent replicated experiments in which female Drosophila melanogaster were subjected to ‘high’ and ‘low’ mating regimes, resulting in highly significant differences in lifespan. We sampled females for transcriptomic analysis at day 10 of life, before the visible onset of ageing, and used Tiling expression arrays to detect differential gene expression in two body parts (abdomen versus head+thorax). The divergent mating regimes were associated with significant differential expression in a network of genes showing evidence for interactions with ecdysone receptor. Preliminary experimental manipulation of two genes in that network with roles in post-transcriptional modification (CG11486, eyegone) tended to enhance sensitivity to mating costs. However, the subtle nature of those effects suggests substantial functional redundancy or parallelism in this gene network, which could buffer females against excessive responses. There was also evidence for differential expression in genes involved in germline maintenance, cell proliferation and in gustation / odorant reception. Interestingly, we detected differential expression in three specific genes (EcR, keap1, lbk1) and one class of genes (gustation / odorant receptors) with previously reported roles in determining lifespan. Our results suggest that high and low mating regimes that lead to divergence in lifespan are associated with changes in the expression of genes such as reproductive hormones, that influence resource allocation to the germ line, and that may modify post-translational gene expression. This predicts that the correct signalling of nutrient levels to the reproductive system is important for maintaining organismal integrity. PMID:23826372

Using probability modelling and genetic parentage assignment to test the role of local mate availability in mating system variation.

PubMed

Blyton, Michaela D J; Banks, Sam C; Peakall, Rod; Lindenmayer, David B

2012-02-01

The formal testing of mating system theories with empirical data is important for evaluating the relative importance of different processes in shaping mating systems in wild populations. Here, we present a generally applicable probability modelling framework to test the role of local mate availability in determining a population's level of genetic monogamy. We provide a significance test for detecting departures in observed mating patterns from model expectations based on mate availability alone, allowing the presence and direction of behavioural effects to be inferred. The assessment of mate availability can be flexible and in this study it was based on population density, sex ratio and spatial arrangement. This approach provides a useful tool for (1) isolating the effect of mate availability in variable mating systems and (2) in combination with genetic parentage analyses, gaining insights into the nature of mating behaviours in elusive species. To illustrate this modelling approach, we have applied it to investigate the variable mating system of the mountain brushtail possum (Trichosurus cunninghami) and compared the model expectations with the outcomes of genetic parentage analysis over an 18-year study. The observed level of monogamy was higher than predicted under the model. Thus, behavioural traits, such as mate guarding or selective mate choice, may increase the population level of monogamy. We show that combining genetic parentage data with probability modelling can facilitate an improved understanding of the complex interactions between behavioural adaptations and demographic dynamics in driving mating system variation. © 2011 Blackwell Publishing Ltd.

Evolution under monogamy feminizes gene expression in Drosophila melanogaster.

PubMed

Hollis, Brian; Houle, David; Yan, Zheng; Kawecki, Tadeusz J; Keller, Laurent

2014-03-18

Many genes have evolved sexually dimorphic expression as a consequence of divergent selection on males and females. However, because the sexes share a genome, the extent to which evolution can shape gene expression independently in each sex is controversial. Here, we use experimental evolution to reveal suboptimal sex-specific expression for much of the genome. By enforcing a monogamous mating system in populations of Drosophila melanogaster for over 100 generations, we eliminated major components of selection on males: female choice and male-male competition. If gene expression is subject to sexually antagonistic selection, relaxed selection on males should cause evolution towards female optima. Monogamous males and females show this pattern of feminization in both the whole-body and head transcriptomes. Genes with male-biased expression patterns evolved decreased expression under monogamy, while genes with female-biased expression evolved increased expression, relative to polygamous populations. Our results demonstrate persistent and widespread evolutionary tension between male and female adaptation.

Natural search algorithms as a bridge between organisms, evolution, and ecology

PubMed Central

Hein, Andrew M.; Carrara, Francesco; Brumley, Douglas R.; Stocker, Roman; Levin, Simon A.

2016-01-01

The ability to navigate is a hallmark of living systems, from single cells to higher animals. Searching for targets, such as food or mates in particular, is one of the fundamental navigational tasks many organisms must execute to survive and reproduce. Here, we argue that a recent surge of studies of the proximate mechanisms that underlie search behavior offers a new opportunity to integrate the biophysics and neuroscience of sensory systems with ecological and evolutionary processes, closing a feedback loop that promises exciting new avenues of scientific exploration at the frontier of systems biology. PMID:27496324

Evolution of external female genital mutilation: why do males harm their mates?

PubMed

Mouginot, Pierick; Uhl, Gabriele; Fromhage, Lutz

2017-11-01

Sperm competition may select for male reproductive traits that influence female mating or oviposition rate. These traits may induce fitness costs to the female; however, they may be costly for the males as well as any decrease in female fitness also affects male fitness. Male adaptations to sperm competition manipulate females by altering not only female behaviour or physiology, but also female morphology. In orb-weaving spiders, mating may entail mutilation of external structures of the female genitalia, which prevents genital coupling with subsequent males. Here, we present a game theoretical model showing that external female genital mutilation is favoured even under relatively high costs of mutilation, and that it is favoured by a high number of mate encounters per female and last-male sperm precedence.

Evolution of external female genital mutilation: why do males harm their mates?

PubMed Central

Uhl, Gabriele

2017-01-01

Sperm competition may select for male reproductive traits that influence female mating or oviposition rate. These traits may induce fitness costs to the female; however, they may be costly for the males as well as any decrease in female fitness also affects male fitness. Male adaptations to sperm competition manipulate females by altering not only female behaviour or physiology, but also female morphology. In orb-weaving spiders, mating may entail mutilation of external structures of the female genitalia, which prevents genital coupling with subsequent males. Here, we present a game theoretical model showing that external female genital mutilation is favoured even under relatively high costs of mutilation, and that it is favoured by a high number of mate encounters per female and last-male sperm precedence. PMID:29291104

The Problem with Paradigms: Bateman's Worldview as a Case Study.

PubMed

Tang-Martinez, Zuleyma; Ryder, T Brandt

2005-11-01

Bateman's principles, their corollaries and predictions constitute a paradigm for the study of sexual selection theory, evolution of mating systems, parental investment theory, and sexual dimorphism in male and female behavior. Some aspects of this paradigm have been challenged in recent years, while others have been supported by empirical and theoretical research. We re-examine Bateman's 1948 paper in detail, including some methodological problems. Additionally, we review three areas in which an over-reliance on Bateman's predictions about sexual dynamics hindered our ability to understand the potential importance of certain behaviors: 1) male mate choice and sperm allocation; 2) the role of females in initiating and soliciting extra-pair copulations and fertilizations; and 3) the role of females in lekking systems, in which recent evidence suggests that copulations with multiple males (polyandrous behavior) may be common. We conclude this introduction to the symposium by emphasizing the heuristic value of Bateman's contributions, as well as the problems that arise when Bateman's paradigm is viewed through the lens of modern behavioral ecology and evolutionary theory.

Crowding, sex ratio and horn evolution in a South African beetle community.

PubMed

Pomfret, Joanne C; Knell, Robert J

2008-02-07

Sexually selected ornaments and weapons are exceptionally variable, even between closely related species. It has long been recognized that some of this diversity can be explained by differences in mating systems between species, but there remains substantial variation between species with similar mating systems. We investigated the roles of sex ratio (measured as operational sex ratio, OSR) and population density (measured as mean male crowding, a measure indicating the average number of conspecific males that an individual male animal will encounter) in determining horn presence in a community of South African dung beetles. Analysis of data from 14 species using a generalized least-squares model incorporating phylogenetic influences found that both OSR and mean crowding were significant predictors of horn presence, with hornless species tending to show female-biased sex ratios and high levels of crowding. The influence of mean crowding on horn diversity between species probably reflects the difficulty of guarding and monopolizing females when many competitors are present, meaning that males who adopt 'scramble' tactics tend to be favoured.

KSC-03PD-1047

NASA Technical Reports Server (NTRS)

2003-01-01

KENNEDY SPACE CENTER, FLA. -- A worker in the Multi-Payload Processing Facility gestures toward the Galaxy Evolution Explorer (GALEX) being prepared for encapsulation. The first part of the fairing is behind him. The spacecraft is already mated to the Pegasus launch vehicle. After encapsulation, the GALEX/Pegasus will be transported to Cape Canaveral Air Force Station and mated to the L-1011 about four days before launch. A new launch date has not been determined.

Genome differentiation of Drosophila melanogaster from a microclimate contrast in Evolution Canyon, Israel

PubMed Central

Hübner, Sariel; Rashkovetsky, Eugenia; Kim, Young Bun; Oh, Jung Hun; Michalak, Katarzyna; Weiner, Dmitry; Korol, Abraham B.; Nevo, Eviatar; Michalak, Pawel

2013-01-01

The opposite slopes of “Evolution Canyon” in Israel have served as a natural model system of adaptation to a microclimate contrast. Long-term studies of Drosophila melanogaster populations inhabiting the canyon have exhibited significant interslope divergence in thermal and drought stress resistance, candidate genes, mobile elements, habitat choice, mating discrimination, and wing-shape variation, all despite close physical proximity of the contrasting habitats, as well as substantial interslope migration. To examine patterns of genetic differentiation at the genome-wide level, we used high coverage sequencing of the flies’ genomes. A total of 572 genes were significantly different in allele frequency between the slopes, 106 out of which were associated with 74 significantly overrepresented gene ontology (GO) terms, particularly so with response to stimulus and developmental and reproductive processes, thus corroborating previous observations of interslope divergence in stress response, life history, and mating functions. There were at least 37 chromosomal “islands” of interslope divergence and low sequence polymorphism, plausible signatures of selective sweeps, more abundant in flies derived from one (north-facing) of the slopes. Positive correlation between local recombination rate and the level of nucleotide polymorphism was also found. PMID:24324170

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

Polyandry as a mediator of sexual selection before and after mating

PubMed Central

Kvarnemo, Charlotta; Simmons, Leigh W.

2013-01-01

The Darwin–Bateman paradigm recognizes competition among males for access to multiple mates as the main driver of sexual selection. Increasingly, however, females are also being found to benefit from multiple mating so that polyandry can generate competition among females for access to multiple males, and impose sexual selection on female traits that influence their mating success. Polyandry can reduce a male's ability to monopolize females, and thus weaken male focused sexual selection. Perhaps the most important effect of polyandry on males arises because of sperm competition and cryptic female choice. Polyandry favours increased male ejaculate expenditure that can affect sexual selection on males by reducing their potential reproductive rate. Moreover, sexual selection after mating can ameliorate or exaggerate sexual selection before mating. Currently, estimates of sexual selection intensity rely heavily on measures of male mating success, but polyandry now raises serious questions over the validity of such approaches. Future work must take into account both pre- and post-copulatory episodes of selection. A change in focus from the products of sexual selection expected in males, to less obvious traits in females, such as sensory perception, is likely to reveal a greater role of sexual selection in female evolution. PMID:23339234

The biosynthetic gene cluster for the cyanogenic glucoside dhurrin in Sorghum bicolor contains its co-expressed vacuolar MATE transporter

PubMed Central

Darbani, Behrooz; Motawia, Mohammed Saddik; Olsen, Carl Erik; Nour-Eldin, Hussam H.; Møller, Birger Lindberg; Rook, Fred

2016-01-01

Genomic gene clusters for the biosynthesis of chemical defence compounds are increasingly identified in plant genomes. We previously reported the independent evolution of biosynthetic gene clusters for cyanogenic glucoside biosynthesis in three plant lineages. Here we report that the gene cluster for the cyanogenic glucoside dhurrin in Sorghum bicolor additionally contains a gene, SbMATE2, encoding a transporter of the multidrug and toxic compound extrusion (MATE) family, which is co-expressed with the biosynthetic genes. The predicted localisation of SbMATE2 to the vacuolar membrane was demonstrated experimentally by transient expression of a SbMATE2-YFP fusion protein and confocal microscopy. Transport studies in Xenopus laevis oocytes demonstrate that SbMATE2 is able to transport dhurrin. In addition, SbMATE2 was able to transport non-endogenous cyanogenic glucosides, but not the anthocyanin cyanidin 3-O-glucoside or the glucosinolate indol-3-yl-methyl glucosinolate. The genomic co-localisation of a transporter gene with the biosynthetic genes producing the transported compound is discussed in relation to the role self-toxicity of chemical defence compounds may play in the formation of gene clusters. PMID:27841372

Polyandry as a mediator of sexual selection before and after mating.

PubMed

Kvarnemo, Charlotta; Simmons, Leigh W

2013-03-05

The Darwin-Bateman paradigm recognizes competition among males for access to multiple mates as the main driver of sexual selection. Increasingly, however, females are also being found to benefit from multiple mating so that polyandry can generate competition among females for access to multiple males, and impose sexual selection on female traits that influence their mating success. Polyandry can reduce a male's ability to monopolize females, and thus weaken male focused sexual selection. Perhaps the most important effect of polyandry on males arises because of sperm competition and cryptic female choice. Polyandry favours increased male ejaculate expenditure that can affect sexual selection on males by reducing their potential reproductive rate. Moreover, sexual selection after mating can ameliorate or exaggerate sexual selection before mating. Currently, estimates of sexual selection intensity rely heavily on measures of male mating success, but polyandry now raises serious questions over the validity of such approaches. Future work must take into account both pre- and post-copulatory episodes of selection. A change in focus from the products of sexual selection expected in males, to less obvious traits in females, such as sensory perception, is likely to reveal a greater role of sexual selection in female evolution.

Mate-choice copying: A fitness-enhancing behavior that evolves by indirect selection.

PubMed

Santos, Mauro; Sapage, Manuel; Matos, Margarida; Varela, Susana A M

2017-06-01

A spatially explicit, individual-based simulation model is used to study the spread of an allele for mate-choice copying (MCC) through horizontal cultural transmission when female innate preferences do or do not coevolve with a male viability-increasing trait. Evolution of MCC is unlikely when innate female preferences coevolve with the trait, as copier females cannot express a higher preference than noncopier females for high-fitness males. However, if a genetic polymorphism for innate preference persists in the population, MCC can evolve by indirect selection through hitchhiking: the copying allele hitchhikes on the male trait. MCC can be an adaptive behavior-that is, a behavior that increases a population's average fitness relative to populations without MCC-even though the copying allele itself may be neutral or mildly deleterious. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Sexual selection favours male parental care, when females can choose

PubMed Central

Alonzo, Suzanne H.

2012-01-01

Explaining the evolution of male care has proved difficult. Recent theory predicts that female promiscuity and sexual selection on males inherently disfavour male care. In sharp contrast to these expectations, male-only care is often found in species with high extra-pair paternity and striking variation in mating success, where current theory predicts female-only care. Using a model that examines the coevolution of male care, female care and female choice; I show that inter-sexual selection can drive the evolution of male care when females are able to bias mating or paternity towards parental males. Surprisingly, female choice for parental males allows male care to evolve despite low relatedness between the male and the offspring in his care. These results imply that predicting how sexual selection affects parental care evolution will require further understanding of why females, in many species, either do not prefer or cannot favour males that provide care. PMID:22171082

When does female multiple mating evolve to adjust inbreeding? Effects of inbreeding depression, direct costs, mating constraints, and polyandry as a threshold trait.

PubMed

Duthie, A Bradley; Bocedi, Greta; Reid, Jane M

2016-09-01

Polyandry is often hypothesized to evolve to allow females to adjust the degree to which they inbreed. Multiple factors might affect such evolution, including inbreeding depression, direct costs, constraints on male availability, and the nature of polyandry as a threshold trait. Complex models are required to evaluate when evolution of polyandry to adjust inbreeding is predicted to arise. We used a genetically explicit individual-based model to track the joint evolution of inbreeding strategy and polyandry defined as a polygenic threshold trait. Evolution of polyandry to avoid inbreeding only occurred given strong inbreeding depression, low direct costs, and severe restrictions on initial versus additional male availability. Evolution of polyandry to prefer inbreeding only occurred given zero inbreeding depression and direct costs, and given similarly severe restrictions on male availability. However, due to its threshold nature, phenotypic polyandry was frequently expressed even when strongly selected against and hence maladaptive. Further, the degree to which females adjusted inbreeding through polyandry was typically very small, and often reflected constraints on male availability rather than adaptive reproductive strategy. Evolution of polyandry solely to adjust inbreeding might consequently be highly restricted in nature, and such evolution cannot necessarily be directly inferred from observed magnitudes of inbreeding adjustment. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Sexual conflict and the evolution of asexuality at low population densities.

PubMed

Gerber, Nina; Kokko, Hanna

2016-10-26

Theories for the evolution of sex rarely include facultatively sexual reproduction. Sexual harassment by males is an underappreciated factor: it should at first sight increase the relative advantage of asexual reproduction by increasing the cost of sex. However, if the same females can perform either sexual or asexual life cycles, then females trying to reproduce asexually may not escape harassment. If resisting male harassment is costly, it might be beneficial for a female to accept a mating and undertake a sexual life cycle rather than 'insist' on an asexual one. We investigate the effects of sexual harassment on the maintenance of sex under different population densities. Our model shows that resisting matings pays off at low population densities, which leads to the complete extinction of males, and thus to the evolution of completely asexual populations. Facultative sex persists in a narrow range of slightly higher densities. At high densities, selection favours giving up resisting male mating attempts and thus sexual reproduction takes over. These interactions between the outcomes of sexual conflict and population density suggest an explanation for the rarity of facultative sex and also patterns of geographical parthenogenesis, where marginal environments with potentially low densities are associated with asexuality. © 2016 The Author(s).

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

Fitness cost of pheromone production in signaling female moths.

PubMed

Harari, Ally R; Zahavi, Tirtza; Thiéry, Denis

2011-06-01

A secondary sexual character may act as an honest signal of the quality of the individual if the trait bears a cost and if its expression is phenotypically condition dependent. The cost of increasing the trait should be tolerable for individuals in good condition but not for those in a poor condition. The trait thus provides an honest signal of quality that enables the receiver to choose higher quality mates. Evidence for sex pheromones, which play a major role in shaping sexual evolution, inflicting a signaling cost is scarce. Here, we demonstrate that the amount of the major component of the pheromone in glands of Lobesia botrana (Lepidoptera) females at signaling time was significantly greater in large than in small females, that male moths preferred larger females as mates when responding to volatile signals, and small virgin females, but not large ones, exposed to conspecific pheromone, produced, when mated, significantly fewer eggs than nonexposed females. The latter indicates a condition-dependent cost of signaling. These results are in accordance with the predictions of condition-dependent honest signals. We therefore suggest that female signaling for males using sex pheromones bears a cost and thus calling may serve as honest advertisement for female quality. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

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.

Life-history differences favor evolution of male dimorphism in competitive games.

PubMed

Smallegange, Isabel M; Johansson, Jacob

2014-02-01

Many species exhibit two discrete male morphs: fighters and sneakers. Fighters are large and possess weapons but may mature slowly. Sneakers are small and have no weapons but can sneak matings and may mature quickly to start mating earlier in life than fighters. However, how differences in competitive ability and life history interact to determine male morph coexistence has not yet been investigated within a single framework. Here we integrate demography and game theory into a two-sex population model to study the evolution of strategies that result in the coexistence of fighters and sneakers. We incorporate differences in maturation time between the morphs and use a mating-probability matrix analogous to the classic hawk-dove game. Using adaptive dynamics, we show that male dimorphism evolves more easily in our model than in classic game theory approaches. Our results also revealed an interaction between life-history differences and sneaker competitiveness, which shows that demography and competitive games should be treated as interlinked mechanisms to understand the evolution of male dimorphism. Applying our approach to empirical data on bulb mites (Rhizoglyphus robini), coho salmon (Oncorhynchus kisutch), and bullhorned dung beetles (Onthophagus taurus) indicates that observed occurrences of male dimorphism are in general agreement with model predictions.

When does female multiple mating evolve to adjust inbreeding? Effects of inbreeding depression, direct costs, mating constraints, and polyandry as a threshold trait

PubMed Central

Duthie, A. Bradley; Bocedi, Greta; Reid, Jane M.

2016-01-01

Polyandry is often hypothesized to evolve to allow females to adjust the degree to which they inbreed. Multiple factors might affect such evolution, including inbreeding depression, direct costs, constraints on male availability, and the nature of polyandry as a threshold trait. Complex models are required to evaluate when evolution of polyandry to adjust inbreeding is predicted to arise. We used a genetically explicit individual‐based model to track the joint evolution of inbreeding strategy and polyandry defined as a polygenic threshold trait. Evolution of polyandry to avoid inbreeding only occurred given strong inbreeding depression, low direct costs, and severe restrictions on initial versus additional male availability. Evolution of polyandry to prefer inbreeding only occurred given zero inbreeding depression and direct costs, and given similarly severe restrictions on male availability. However, due to its threshold nature, phenotypic polyandry was frequently expressed even when strongly selected against and hence maladaptive. Further, the degree to which females adjusted inbreeding through polyandry was typically very small, and often reflected constraints on male availability rather than adaptive reproductive strategy. Evolution of polyandry solely to adjust inbreeding might consequently be highly restricted in nature, and such evolution cannot necessarily be directly inferred from observed magnitudes of inbreeding adjustment. PMID:27464756

The evolution of costly mate choice against segregation distorters.

PubMed

Manser, Andri; Lindholm, Anna K; Weissing, Franz J

2017-12-01

The evolution of female preference for male genetic quality remains a controversial topic in sexual selection research. One well-known problem, known as the lek paradox, lies in understanding how variation in genetic quality is maintained in spite of natural selection and sexual selection against low-quality alleles. Here, we theoretically investigate a scenario where females pay a direct fitness cost to avoid males carrying an autosomal segregation distorter. We show that preference evolution is greatly facilitated under such circumstances. Because the distorter is transmitted in a non-Mendelian fashion, it can be maintained in the population despite directional sexual selection. The preference helps females avoid fitness costs associated with the distorter. Interestingly, we find that preference evolution is limited if the choice allele induces a very strong preference or if distortion is very strong. Moreover, the preference can only persist in the presence of a signal that reliably indicates a male's distorter genotype. Hence, even in a system where the lek paradox does not play a major role, costly preferences can only spread under specific circumstances. We discuss the importance of distorter systems for the evolution of costly female choice and potential implications for the use of artificial distorters in pest control. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Monogamy and high relatedness do not preferentially favor the evolution of cooperation.

PubMed

Nonacs, Peter

2011-03-04

Phylogenetic analyses strongly associate nonsocial ancestors of cooperatively-breeding or eusocial species with monogamy. Because monogamy creates high-relatedness family groups, kin selection has been concluded to drive the evolution of cooperative breeding (i.e., the monogamy hypothesis). Although kin selection is criticized as inappropriate for modeling and predicting the evolution of cooperation, there are no examples where specific inclusive fitness-based predictions are intrinsically wrong. The monogamy hypothesis may be the first case of such a flawed calculation. A simulation model mutated helping alleles into non-cooperative populations where females mated either once or multiply. Although multiple mating produces sibling broods of lower relatedness, it also increases the likelihood that one offspring will adopt a helper role. Examining this tradeoff showed that under a wide range of conditions polygamy, rather than monogamy, allowed helping to spread more rapidly through populations. Further simulations with mating strategies as heritable traits confirmed that multiple-mating is selectively advantageous. Although cooperation evolves similarly regardless of whether dependent young are close or more distant kin, it does not evolve if they are unrelated. The solitary ancestral species to cooperative breeders may have been predominantly monogamous, but it cannot be concluded that monogamy is a predisposing state for the evolution of helping behavior. Monogamy may simply be coincidental to other more important life history characteristics such as nest defense or sequential provisioning of offspring. The differing predictive outcome from a gene-based model also supports arguments that inclusive fitness formulations poorly model some evolutionary questions. Nevertheless, cooperation only evolves when benefits are provided for kin: helping alleles did not increase in frequency in the absence of potential gains in indirect fitness. The key question, therefore, is not whether kin selection occurs, but how best to elucidate the differing evolutionary advantages of genetic relatedness versus genetic diversity.

Monogamy and high relatedness do not preferentially favor the evolution of cooperation

PubMed Central

2011-01-01

Background Phylogenetic analyses strongly associate nonsocial ancestors of cooperatively-breeding or eusocial species with monogamy. Because monogamy creates high-relatedness family groups, kin selection has been concluded to drive the evolution of cooperative breeding (i.e., the monogamy hypothesis). Although kin selection is criticized as inappropriate for modeling and predicting the evolution of cooperation, there are no examples where specific inclusive fitness-based predictions are intrinsically wrong. The monogamy hypothesis may be the first case of such a flawed calculation. Results A simulation model mutated helping alleles into non-cooperative populations where females mated either once or multiply. Although multiple mating produces sibling broods of lower relatedness, it also increases the likelihood that one offspring will adopt a helper role. Examining this tradeoff showed that under a wide range of conditions polygamy, rather than monogamy, allowed helping to spread more rapidly through populations. Further simulations with mating strategies as heritable traits confirmed that multiple-mating is selectively advantageous. Although cooperation evolves similarly regardless of whether dependent young are close or more distant kin, it does not evolve if they are unrelated. Conclusions The solitary ancestral species to cooperative breeders may have been predominantly monogamous, but it cannot be concluded that monogamy is a predisposing state for the evolution of helping behavior. Monogamy may simply be coincidental to other more important life history characteristics such as nest defense or sequential provisioning of offspring. The differing predictive outcome from a gene-based model also supports arguments that inclusive fitness formulations poorly model some evolutionary questions. Nevertheless, cooperation only evolves when benefits are provided for kin: helping alleles did not increase in frequency in the absence of potential gains in indirect fitness. The key question, therefore, is not whether kin selection occurs, but how best to elucidate the differing evolutionary advantages of genetic relatedness versus genetic diversity. PMID:21375755

Sociality, mating system and reproductive skew in marmots: evidence and hypotheses.

PubMed

Allainé

2000-10-05

Marmot species exhibit a great diversity of social structure, mating systems and reproductive skew. In particular, among the social species (i.e. all except Marmota monax), the yellow-bellied marmot appears quite different from the others. The yellow-bellied marmot is primarily polygynous with an intermediate level of sociality and low reproductive skew among females. In contrast, all other social marmot species are mainly monogamous, highly social and with marked reproductive skew among females. To understand the evolution of this difference in reproductive skew, I examined four possible explanations identified from reproductive skew theory. From the literature, I then reviewed evidence to investigate if marmot species differ in: (1) the ability of dominants to control the reproduction of subordinates; (2) the degree of relatedness between group members; (3) the benefit for subordinates of remaining in the social group; and (4) the benefit for dominants of retaining subordinates. I found that the optimal skew hypothesis may apply for both sets of species. I suggest that yellow-bellied marmot females may benefit from retaining subordinate females and in return have to concede them reproduction. On the contrary, monogamous marmot species may gain by suppressing the reproduction of subordinate females to maximise the efficiency of social thermoregulation, even at the risk of departure of subordinate females from the family group. Finally, I discuss scenarios for the simultaneous evolution of sociality, monogamy and reproductive skew in marmots.

Mate Choice in Mus musculus Is Relative and Dependent on the Estrous State

PubMed Central

Zinck, Léa; Lima, Susana Q.

2013-01-01

Mate choice is a critical behavioral decision process with profound impact on evolution. However, the mechanistic basis of mate choice is poorly understood. In this study we focused on assortative mate choice, which is known to contribute to the reproductive isolation of the two European subspecies of house mouse, Mus musculus musculus and Mus musculus domesticus. To understand the decision process, we developed both full mating and limited-contact paradigms and tested musculus females' preference for musculus versus domesticus males, mimicking the natural musculus/domesticus contact zone. As hypothesized, when allowed to mate we found that sexually receptive musculus females exhibited a robust preference to mate with musculus males. In contrast, when non-receptive, females did not exhibit a preference and rather alternated between males in response to male mount attempts. Moreover in a no-choice condition, females mated readily with males from both subspecies. Finally, when no physical contact was allowed, and therefore male's behavior could not influence female's behavior, female's preference for its own subspecies was maintained independently of the estrous state. Together, our results suggest that the assortative preference is relative and based on a comparison of the options available rather than on an absolute preference. The results of the limited-contact experiments highlight the interplay between female's internal state and the nature of the interaction with prospective mates in the full mating conditions. With these experiments we believe we established an assortative mate preference assay that is appropriate for the investigation of its underlying substrates. PMID:23762466

KSC-99pp0654

NASA Image and Video Library

1999-06-07

The second stage of a Boeing Delta II rocket is lifted up the launch tower at Launch Pad 17A, Cape Canaveral Air Station (CCAS). The first and second stages will be mated for the launch, targeted on June 23 at CCAS, of NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite,. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum

KSC-99pp0657

NASA Image and Video Library

1999-06-07

Workers oversee the mating of the second stage with the first stage of a Boeing Delta II rocket, which will launch the NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE is NASA's Far Ultraviolet Spectroscopic Explorer satellite developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum. FUSE is scheduled to launch June 23 at Launch Pad 17A, Cape Canaveral Air Station

KSC-99pp0655

NASA Image and Video Library

1999-06-07

The second stage of a Boeing Delta II rocket is moved inside the launch tower at Launch Pad 17A, Cape Canaveral Air Station (CCAS). The first and second stages will be mated for the launch, targeted on June 23 at CCAS, of NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum

Reproductive ecology of lampreys

USGS Publications Warehouse

Johnson, Nicholas S.; Buchinger, Tyler J.; Li, Weiming

2014-01-01

Lampreys typically spawn in riffle habitats during the spring. Spawning activity and diel (i.e., during daylight and at night) behavioral patterns are initiated when spring water temperatures increase to levels that coincide with optimal embryologic development. Nests are constructed in gravel substrate using the oral disc to move stones and the tail to fan sediment out of the nest. Spawning habitat used by individual species is generally a function of adult size, where small-bodied species construct nests in shallower water with slower flow and smaller gravel than large-bodied species. The mating system of lampreys is primarily polygynandrous (i.e., where multiple males mate with multiple females). Lamprey species with adult total length less than 30 cm generally spawn communally, where a nest may contain 20 or more individuals of both sexes. Lamprey species with adult sizes greater than 35 cm generally spawn in groups of two to four. Operational sex ratios of lampreys are highly variable across species, populations, and time, but are generally male biased. The act of spawning typically starts with the male attaching with his oral disc to the back of the female’s head; the male and female then entwine and simultaneously release gametes. However, alternative mating behaviors (e.g., release of gametes without paired courtship and sneaker males) have been observed. Future research should determine how multiple modalities of communication among lampreys (including mating pheromones) are integrated to inform species recognition and mate choice. Such research could inform both sea lamprey control strategies and provide insight into possible evolution of reproductive isolation mechanisms between paired lamprey species in sympatry.

Sexually Antagonistic Male Signals Manipulate Germline and Soma of C. elegans Hermaphrodites.

PubMed

Aprison, Erin Z; Ruvinsky, Ilya

2016-10-24

Males and females pursue different reproductive strategies, which often bring them into conflict-many traits exist that benefit one sex at a cost to another [1]. Decreased female survival following mating dramatically demonstrates one aspect of this phenomenon [2-5]. Particularly intriguing is the evidence that secreted compounds can shorten lifespan of members of the opposite sex in Drosophila [6] and Caenorhabditid nematodes [7] even without copulation taking place. The purpose of such signals is not clear, however. While it is possible that they could limit subsequent mating with competitors or hasten post-reproductive demise, thus decreasing competition for resources, they are also likely to harm unmated individuals. Why would a system exist that reduces the vigor of potential mates prior to mating? Addressing this question could provide insights into mechanisms and evolution of sexual conflict and reveal sensory inputs that regulate aging. Here, we describe two distinct ways in which Caenorhabditis elegans males cause faster somatic aging of hermaphrodites but also manipulate different aspects of their reproductive physiology. The first, mediated by conserved ascaroside pheromones, delays the loss of germline progenitor cells. The second accelerates development, resulting in faster sexual maturation. These signals promote male reproductive strategy and the effects harmful to hermaphrodites appear to be collateral damage rather than the goal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sexual behavior, reproductive physiology and sperm competition in male mammals.

PubMed

Dixson, Alan F; Anderson, Matthew J

2004-11-15

Sperm competition involves competition between the gametes of two or more males of a species for fertilization of a given set of ova. Sperm competition is widespread among mammals, as in many other groups of vertebrates. Effects of sexual selection, via sperm competition, upon the evolution of reproductive physiology and behavior are much better understood in invertebrates (and especially in insects) than is the case for mammals. However, if the reproductive organs of male mammals are viewed as an integrated system for production and delivery of spermatozoa (and accessory glandular secretions) to females, then it is logical to assume that sperm competition might influence the evolution of all parts of the system, as well as associated physiological mechanisms (e.g., testicular endocrinology) and behavior (e.g., copulatory patterns). Here we analyze and review relationships between mating systems, relative testes sizes and sperm morphology, phallic morphology, circulating testosterone levels and sexual behavior in male mammals.

Promiscuous mating in the harem-roosting fruit bat, Cynopterus sphinx.

PubMed

Garg, Kritika M; Chattopadhyay, Balaji; Doss D, Paramanatha Swami; A K, Vinoth Kumar; Kandula, Sripathi; Ramakrishnan, Uma

2012-08-01

Observations on mating behaviours and strategies guide our understanding of mating systems and variance in reproductive success. However, the presence of cryptic strategies often results in situations where social mating system is not reflective of genetic mating system. We present such a study of the genetic mating system of a harem-forming bat Cynopterus sphinx where harems may not be true indicators of male reproductive success. This temporal study using data from six seasons on paternity reveals that social harem assemblages do not play a role in the mating system, and variance in male reproductive success is lower than expected assuming polygynous mating. Further, simulations reveal that the genetic mating system is statistically indistinguishable from promiscuity. Our results are in contrast to an earlier study that demonstrated high variance in male reproductive success. Although an outcome of behavioural mating patterns, standardized variance in male reproductive success (I(m)) affects the opportunity for sexual selection. To gain a better understanding of the evolutionary implications of promiscuity for mammals in general, we compared our estimates of I(m) and total opportunity for sexual selection (I(m) /I(f), where I(f) is standardized variance in female reproductive success) with those of other known promiscuous species. We observed a broad range of I(m) /I(f) values across known promiscuous species, indicating our poor understanding of the evolutionary implications of promiscuous mating. © 2012 Blackwell Publishing Ltd.

Looking for a similar partner: host plants shape mating preferences of herbivorous insects by altering their contact pheromones.

PubMed

Geiselhardt, Sven; Otte, Tobias; Hilker, Monika

2012-09-01

The role of phenotypical plasticity in ecological speciation and the evolution of sexual isolation remains largely unknown. We investigated whether or not divergent host plant use in an herbivorous insect causes assortative mating by phenotypically altering traits involved in mate recognition. We found that males of the mustard leaf beetle Phaedon cochleariae preferred to mate with females that were reared on the same plant species to females provided with a different plant species, based on divergent cuticular hydrocarbon profiles that serve as contact pheromones. The cuticular hydrocarbon phenotypes of the beetles were host plant specific and changed within 2 weeks after a shift to a novel host plant species. We suggest that plant-induced phenotypic divergence in mate recognition cues may act as an early barrier to gene flow between herbivorous insect populations on alternative host species, preceding genetic divergence and thus, promoting ecological speciation. © 2012 Blackwell Publishing Ltd/CNRS.

Mated vertical ground vibration test

NASA Technical Reports Server (NTRS)

Ivey, E. W.

1980-01-01

The Mated Vertical Ground Vibration Test (MVGVT) was considered to provide an experimental base in the form of structural dynamic characteristics for the shuttle vehicle. This data base was used in developing high confidence analytical models for the prediction and design of loads, pogo controls, and flutter criteria under various payloads and operational missions. The MVGVT boost and launch program evolution, test configurations, and their suspensions are described. Test results are compared with predicted analytical results.

Effects of maternal lines and mating systems on lamb carcass merit

USDA-ARS?s Scientific Manuscript database

Objectives: The objective of this study was to analyze the carcass composition of lambs produced from different mating systems. Materials and Methods: Lambs (n = 1,237) were produced by a multi- sire mating of three maternal lines (Katahdin (KN), Polypay (PP), and Easycare (EZ)) in two mating system...

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

Phylogenetic distribution of a male pheromone that may exploit a nonsexual preference in lampreys

USGS Publications Warehouse

Buchinger, Tyler J.; Bussy, Ugo; Li, Ke; Wang, Huiyong; Huertas, Mar; Baker, Cindy F.; Jia, Liang; Hayes, Michael C.; Li, Weiming; Johnson, Nicholas

2017-01-01

Pheromones are among the most important sexual signals used by organisms throughout the animal kingdom. However, few are identified in vertebrates, leaving the evolutionary mechanisms underlying vertebrate pheromones poorly understood. Pre-existing biases in receivers’ perceptual systems shape visual and auditory signaling systems, but studies on how receiver biases influence the evolution of pheromone communication remain sparse. The lamprey Petromyzon marinus uses a relatively well-understood suite of pheromones and offers a unique opportunity to study the evolution of vertebrate pheromone communication. Previous studies indicate that male signaling with the mating pheromone 3-keto petromyzonol sulfate (3kPZS) may exploit a nonsexual attraction to juvenile-released 3kPZS that guides migration into productive rearing habitat. Here, we infer the distribution of male signaling with 3kPZS using a phylogenetic comparison comprising six of ten genera and two of three families. Our results indicate that only P. marinus and Ichthyomyzon castaneus release 3kPZS at high rates. Olfactory and behavioral assays with P. marinus, I. castaneus and a subset of three other species that do not use 3kPZS as a sexual signal indicate that male signaling might drive the evolution of female adaptations to detect 3kPZS with specific olfactory mechanisms and respond to 3kPZS with targeted attraction relevant during mate search. We postulate that 3kPZS communication evolved independently in I. castaneus and P. marinus, but cannot eliminate the alternative that other species lost 3kPZS communication. Regardless, our results represent a rare macroevolutionary investigation of a vertebrate pheromone and insight into the evolutionary mechanisms underlying pheromone communication.

Sparkling feather reflections of a bird-of-paradise explained by finite-difference time-domain modeling

PubMed Central

Wilts, Bodo D.; Michielsen, Kristel; De Raedt, Hans; Stavenga, Doekele G.

2014-01-01

Birds-of-paradise are nature’s prime examples of the evolution of color by sexual selection. Their brilliant, structurally colored feathers play a principal role in mating displays. The structural coloration of both the occipital and breast feathers of the bird-of-paradise Lawes’ parotia is produced by melanin rodlets arranged in layers, together acting as interference reflectors. Light reflection by the silvery colored occipital feathers is unidirectional as in a classical multilayer, but the reflection by the richly colored breast feathers is three-directional and extraordinarily complex. Here we show that the reflection properties of both feather types can be quantitatively explained by finite-difference time-domain modeling using realistic feather anatomies and experimentally determined refractive index dispersion values of keratin and melanin. The results elucidate the interplay between avian coloration and vision and indicate tuning of the mating displays to the spectral properties of the avian visual system. PMID:24591592

Sparkling feather reflections of a bird-of-paradise explained by finite-difference time-domain modeling.

PubMed

Wilts, Bodo D; Michielsen, Kristel; De Raedt, Hans; Stavenga, Doekele G

2014-03-25

Birds-of-paradise are nature's prime examples of the evolution of color by sexual selection. Their brilliant, structurally colored feathers play a principal role in mating displays. The structural coloration of both the occipital and breast feathers of the bird-of-paradise Lawes' parotia is produced by melanin rodlets arranged in layers, together acting as interference reflectors. Light reflection by the silvery colored occipital feathers is unidirectional as in a classical multilayer, but the reflection by the richly colored breast feathers is three-directional and extraordinarily complex. Here we show that the reflection properties of both feather types can be quantitatively explained by finite-difference time-domain modeling using realistic feather anatomies and experimentally determined refractive index dispersion values of keratin and melanin. The results elucidate the interplay between avian coloration and vision and indicate tuning of the mating displays to the spectral properties of the avian visual system.

Pollinators' mating rendezvous and the evolution of floral advertisement.

PubMed

Fishman, Michael A; Hadany, Lilach

2013-01-07

Successful cross-fertilization in plant species that rely on animal pollinators depends not just on the number of pollinator visits, but also on these visits' duration. Furthermore, in non-deceptive pollination, a visit's duration depends on the magnitude of the reward provided to the pollinator. Accordingly, plants that rely on biotic pollination have to partition their investment in cross-fertilization assurance between attracting pollinator visits - advertisement, and rewarding visitors to assure that the visit is of productive duration. Here we analyze these processes by a combination of optimality methods and game theoretical modeling. Our results indicate that the optimality in such allocation of resources depends on the types of reward offered to the pollinators. More precisely, we show that plants that offer both food reward and mating rendezvous to pollinators will evolve to allocate a higher proportion of their cross-fertilization assurance budget to advertisement than plants that offer only food reward. That is, our results indicate that pollinators' mating habits may play a role in floral evolution. Copyright © 2012 Elsevier Ltd. All rights reserved.

Parallel evolution of sexual isolation in sticklebacks.

PubMed

Boughman, Janette Wenrick; Rundle, Howard D; Schluter, Dolph

2005-02-01

Mechanisms of speciation are not well understood, despite decades of study. Recent work has focused on how natural and sexual selection cause sexual isolation. Here, we investigate the roles of divergent natural and sexual selection in the evolution of sexual isolation between sympatric species of threespine sticklebacks. We test the importance of morphological and behavioral traits in conferring sexual isolation and examine to what extent these traits have diverged in parallel between multiple, independently evolved species pairs. We use the patterns of evolution in ecological and mating traits to infer the likely nature of selection on sexual isolation. Strong parallel evolution implicates ecologically based divergent natural and/or sexual selection, whereas arbitrary directionality implicates nonecological sexual selection or drift. In multiple pairs we find that sexual isolation arises in the same way: assortative mating on body size and asymmetric isolation due to male nuptial color. Body size and color have diverged in a strongly parallel manner, similar to ecological traits. The data implicate ecologically based divergent natural and sexual selection as engines of speciation in this group.

MATE standardization

NASA Astrophysics Data System (ADS)

Farmer, R. E.

1982-11-01

The MATE (Modular Automatic Test Equipment) program was developed to combat the proliferation of unique, expensive ATE within the Air Force. MATE incorporates a standard management approach and a standard architecture designed to implement a cradle-to-grave approach to the acquisition of ATE and to significantly reduce the life cycle cost of weapons systems support. These standards are detailed in the MATE Guides. The MATE Guides assist both the Air Force and Industry in implementing the MATE concept, and provide the necessary tools and guidance required for successful acquisition of ATE. The guides also provide the necessary specifications for industry to build MATE-qualifiable equipment. The MATE architecture provides standards for all key interfaces of an ATE system. The MATE approach to the acquisition and management of ATE has been jointly endorsed by the commanders of Air Force Systems Command and Air Force Logistics Command as the way of doing business in the future.

Phase Transition Behavior in a Neutral Evolution Model

NASA Astrophysics Data System (ADS)

King, Dawn; Scott, Adam; Maric, Nevena; Bahar, Sonya

2014-03-01

The complexity of interactions among individuals and between individuals and the environment make agent based modeling ideal for studying emergent speciation. This is a dynamically complex problem that can be characterized via the critical behavior of a continuous phase transition. Concomitant with the main tenets of natural selection, we allow organisms to reproduce, mutate, and die within a neutral phenotype space. Previous work has shown phase transition behavior in an assortative mating model with variable fitness landscapes as the maximum mutation size (μ) was varied (Dees and Bahar, 2010). Similarly, this behavior was recently presented in the work of Scott et al. (2013), even on a completely neutral landscape, for bacterial-like fission as well as for assortative mating. Here we present another neutral model to investigate the `critical' phase transition behavior of three mating types - assortative, bacterial, and random - in a phenotype space as a function of the percentage of random death. Results show two types of phase transitions occurring for the parameters of the population size and the number of clusters (an analogue of species), indicating different evolutionary dynamics for system survival and clustering. This research was supported by funding from: University of Missouri Research Board and James S. McDonnell Foundation.

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.

Exact Markov chains versus diffusion theory for haploid random mating.

PubMed

Tyvand, Peder A; Thorvaldsen, Steinar

2010-05-01

Exact discrete Markov chains are applied to the Wright-Fisher model and the Moran model of haploid random mating. Selection and mutations are neglected. At each discrete value of time t there is a given number n of diploid monoecious organisms. The evolution of the population distribution is given in diffusion variables, to compare the two models of random mating with their common diffusion limit. Only the Moran model converges uniformly to the diffusion limit near the boundary. The Wright-Fisher model allows the population size to change with the generations. Diffusion theory tends to under-predict the loss of genetic information when a population enters a bottleneck. 2010 Elsevier Inc. All rights reserved.

Bioluminescence in the Ocean: Origins of Biological, Chemical, and Ecological Diversity

NASA Astrophysics Data System (ADS)

Widder, E. A.

2010-05-01

From bacteria to fish, a remarkable variety of marine life depends on bioluminescence (the chemical generation of light) for finding food, attracting mates, and evading predators. Disparate biochemical systems and diverse phylogenetic distribution patterns of light-emitting organisms highlight the ecological benefits of bioluminescence, with biochemical and genetic analyses providing new insights into the mechanisms of its evolution. The origins and functions of some bioluminescent systems, however, remain obscure. Here, I review recent advances in understanding bioluminescence in the ocean and highlight future research efforts that will unite molecular details with ecological and evolutionary relationships.

Male-mimicking females increase male-male interactions, and decrease male survival and condition in a female-polymorphic damselfly.

PubMed

Gering, Eben J

2017-05-01

Biologists are still discovering diverse and powerful ways sexual conflicts shape biodiversity. The present study examines how the proportion of females in a population that exhibit male mimicry, a mating resistance trait, influences conspecific males' behavior, condition, and survival. Like most female-polymorphic damselflies, Ischnura ramburii harbors both "andromorph" females, which closely resemble males, and sexually dimorphic "gynomorph" counterparts. There is evidence that male mimicry helps andromorphs evade detection and harassment, but males can also learn to target locally prevalent morph(s) via prior mate encounters. I hypothesized that the presence of male mimics could therefore predispose males to mate recognition errors, and thereby increase rates of costly male-male interactions. Consistent with this hypothesis, male-male interaction rates were highest in mesocosms containing more andromorph (vs. gynomorph) females. Males in andromorph-biased mesocosms also had lower final body mass and higher mortality than males assigned to gynomorph-majority treatments. Male survival and body mass were each negatively affected by mesocosm density, and mortality data revealed a marginally significant interaction between andromorph frequency and population density. These findings suggest that, under sufficiently crowded conditions, female mating resistance traits such as male mimicry could have pronounced indirect effects on male behavior, condition, and survival. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Post-copulatory sexual selection and female fitness in Scathophaga stercoraria.

PubMed

Martin, Oliver Y; Hosken, David J; Ward, Paul I

2004-02-22

Whether sexual selection increases or decreases female fitness is determined by the occurrence and relative importance of sexual-conflict processes and the ability of females to choose high-quality males. Experimentally enforced polyandry and monogamy have previously been shown to cause rapid evolution in the yellow dung fly Scathophaga stercoraria. Flies from polyandrous lines invested more in reproductive tissue, and this investment influenced paternity in sperm competition, but came at a cost to immune function. While some fitness consequences of enforced polyandry or monogamy have been examined when flies mate multiply, the consequences for female fitness when singly copulated remain unexplored. Under a good-genes scenario females from polyandrous lines should be of higher general quality and should outperform females from monogamous lines even with a single copulation. Under sexual conflict, costly adaptations will afford no advantages when females are allowed to mate only once. We investigate the lifetime reproductive success and longevity of females evolving under enforced monogamy or polyandry when mating once with males from these selection regimes. Females from polyandrous lines were found to have lower fitness than their monogamous counterparts when mating once. They died earlier and produced significantly fewer eggs and offspring. These results suggest that sexual conflict probably drove evolution under enforced polyandry as female fitness did not increase overall as expected with purely good-genes effects.

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.

Common effect of the mucus transferred during mating in two dart-shooting snail species from different families.

PubMed

Kimura, Kazuki; Chiba, Satoshi; Koene, Joris M

2014-04-01

Several taxa of pulmonate land snails exhibit a conspicuous mating behaviour, the shooting of so-called love darts. During mating, such land snail species stab a mating partner with a mucus-coated dart. It has previously been shown that the sperm donor physiologically influences the sperm recipient via the mucus covering the dart and thereby decreases the number of sperm digested by the recipient. However, the generality of this effect of the dart's mucus is unclear, because almost all the previous studies on the effect of the mucus used the brown garden snail Cornu aspersum from the family Helicidae. Therefore, the relationship between the acquisition of the mucus effect on the recipient and the evolution of the dart itself, and its mucus, is still open to debate. To test the commonality of the physiological effect of the dart mucus, we examined this in Euhadra peliomphala, a species from the Bradybaenidae family, and compared our findings with the results of previous work using C. aspersum. Our experiments showed that in E. peliomphala, the dart mucus had a physiological effect and lowered the accessibility of the gametolytic organ, as found in C. aspersum. This indicates that in various dart-bearing species the mucus from the dart glands targets the same organ and that the inhibition of sperm digestion has played a crucial role in the evolution of the dart and its mucus.

An Evolutionary Perspective on Yeast Mating-Type Switching

PubMed Central

Hanson, Sara J.; Wolfe, Kenneth H.

2017-01-01

Cell differentiation in yeast species is controlled by a reversible, programmed DNA-rearrangement process called mating-type switching. Switching is achieved by two functionally similar but structurally distinct processes in the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. In both species, haploid cells possess one active and two silent copies of the mating-type locus (a three-cassette structure), the active locus is cleaved, and synthesis-dependent strand annealing is used to replace it with a copy of a silent locus encoding the opposite mating-type information. Each species has its own set of components responsible for regulating these processes. In this review, we summarize knowledge about the function and evolution of mating-type switching components in these species, including mechanisms of heterochromatin formation, MAT locus cleavage, donor bias, lineage tracking, and environmental regulation of switching. We compare switching in these well-studied species to others such as Kluyveromyces lactis and the methylotrophic yeasts Ogataea polymorpha and Komagataella phaffii. We focus on some key questions: Which cells switch mating type? What molecular apparatus is required for switching? Where did it come from? And what is the evolutionary purpose of switching? PMID:28476860

From Preferred to Actual Mate Characteristics: The Case of Human Body Shape

PubMed Central

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

2010-01-01

The way individuals pair to produce reproductive units is a major factor determining evolution. This process is complex because it is determined not only by individual mating preferences, but also by numerous other factors such as competition between mates. Consequently, preferred and actual characteristics of mates obtained should differ, but this has rarely been addressed. We simultaneously measured mating preferences for stature, body mass, and body mass index, and recorded corresponding actual partner's characteristics for 116 human couples from France. Results show that preferred and actual partner's characteristics differ for male judges, but not for females. In addition, while the correlation between all preferred and actual partner's characteristics appeared to be weak for female judges, it was strong for males: while men prefer women slimmer than their actual partner, those who prefer the slimmest women also have partners who are slimmer than average. This study therefore suggests that the influences of preferences on pair formation can be sex-specific. It also illustrates that this process can lead to unexpected results on the real influences of mating preferences: traits considered as highly influencing attractiveness do not necessarily have a strong influence on the actual pairing, the reverse being also possible. PMID:20885953

Variation in the strength of male mate choice allows long-term coexistence of sperm-dependent asexuals and their sexual hosts.

PubMed

Mee, Jonathan A; Otto, Sarah P

2010-10-01

In several asexual taxa, reproduction requires mating with related sexual species to stimulate egg development, even though genetic material is not incorporated from the sexuals (gynogenesis). In cases in which gynogens do not invest in male function, they can potentially have a twofold competitive advantage over sexuals because the asexuals avoid the cost of producing males. If unmitigated, however, the competitive success of the asexuals would ultimately lead to their own demise, following the extinction of the sexual species that stimulate egg development. We have studied a model of mate choice among sexual individuals and asexual gynogens, where males of the sexual species preferentially mate with sexual females over gynogenetic females, to determine if such mating preferences can stably maintain both gynogenetic and sexual individuals within a community. Our model shows that stable coexistence of gynogens and their sexual hosts can occur when there is variation among males in the degree of preference for mating with sexual females and when pickier males pay a higher cost of preference. © 2010 The Author(s). Journal compilation © 2010 The Society for the Study of Evolution.

Sexual selection on cuticular hydrocarbons in the Australian field cricket, Teleogryllus oceanicus

PubMed Central

Thomas, Melissa L; Simmons, Leigh W

2009-01-01

Background Females in a wide range of taxa have been shown to base their choice of mates on pheromone signals. However, little research has focussed specifically on the form and intensity of selection that mate choice imposes on the pheromone signal. Using multivariate selection analysis, we characterise directly the form and intensity of sexual selection acting on cuticular hydrocarbons, chemical compounds widely used in the selection of mates in insects. Using the Australian field cricket Teleogryllus oceanicus as a model organism, we use three measures of male attractiveness to estimate fitness; mating success, the duration of courtship required to elicit copulation, and subsequent spermatophore attachment duration. Results We found that all three measures of male attractiveness generated sexual selection on male cuticular hydrocarbons, however there were differences in the form and intensity of selection among these three measures. Mating success was the only measure of attractiveness that imposed both univariate linear and quadratic selection on cuticular hydrocarbons. Although we found that all three attractiveness measures generated nonlinear selection, again only mating success was found to exert statistically significant stabilizing selection. Conclusion This study shows that sexual selection plays an important role in the evolution of male cuticular hydrocarbon signals. PMID:19594896

From preferred to actual mate characteristics: the case of human body shape.

PubMed

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

2010-09-27

The way individuals pair to produce reproductive units is a major factor determining evolution. This process is complex because it is determined not only by individual mating preferences, but also by numerous other factors such as competition between mates. Consequently, preferred and actual characteristics of mates obtained should differ, but this has rarely been addressed. We simultaneously measured mating preferences for stature, body mass, and body mass index, and recorded corresponding actual partner's characteristics for 116 human couples from France. Results show that preferred and actual partner's characteristics differ for male judges, but not for females. In addition, while the correlation between all preferred and actual partner's characteristics appeared to be weak for female judges, it was strong for males: while men prefer women slimmer than their actual partner, those who prefer the slimmest women also have partners who are slimmer than average. This study therefore suggests that the influences of preferences on pair formation can be sex-specific. It also illustrates that this process can lead to unexpected results on the real influences of mating preferences: traits considered as highly influencing attractiveness do not necessarily have a strong influence on the actual pairing, the reverse being also possible.

Heritable variation of sex pheromone composition and the potential for evolution of resistance to pheromone-based control of the Indian meal moth, Plodia interpunctella.

PubMed

Svensson, Glenn P; Ryne, Camilla; Löfstedt, Christer

2002-07-01

The short-term evolutionary effect of pheromone-based mating disruption on the mating ability of the Indian meal moth, Plodia interpunctella, was investigated. Three independent selection lines were established, and the mating ability of moths in plastic tents treated with high doses of pheromone and in control tents was compared for two consecutive generations. In addition, the heritability of the sex pheromone blend, measured as the ratio of two major pheromone components (Z,E)-9,12-tetradecadienyl acetate and (Z,E)-9,12-tetradecadienol, was estimated. Based on a mother-daughter regression analysis including 21 families, the heritability of the pheromone blend was 0.65 +/- 0.14, indicating a potential for evolutionary change of the character. However, no increase in mating ability of females in pheromone-treated tents or alteration of the pheromone blend was observed in any selection line when compared with control lines, indicating no or weak selection on the pheromone blend as well as other traits influencing mating ability of this species under the created mating disruption conditions. Factors contributing to the lack of selection effects are discussed.

Evidence of Polyandry for Aedes aegypti in Semifield Enclosures

PubMed Central

Helinski, Michelle E. H.; Valerio, Laura; Facchinelli, Luca; Scott, Thomas W.; Ramsey, Janine; Harrington, Laura C.

2012-01-01

Female Aedes aegypti are assumed to be primarily monandrous (i.e., mate only once in their lifetime), but true estimates of mating frequency have not been determined outside the laboratory. To assess polyandry in Ae. aegypti with first-generation progeny from wild mosquitoes, stable isotope semen-labeled males (15N or 13C) were allowed to mate with unlabeled females in semifield enclosures (22.5 m3) in a dengue-endemic area in southern Mexico. On average, 14% of females were positive for both labels, indicating that they received semen from more than one male. Our results provide evidence of a small but potentially significant rate of multiple mating within a 48-hour period and provide an approach for future open-field studies of polyandry in this species. Polyandry has implications for understanding mosquito ecology, evolution, and reproductive behavior as well as genetic strategies for mosquito control. PMID:22492148

Water turbidity by algal blooms causes mating system breakdown in a shallow-water fish, the sand goby Pomatoschistus minutus.

PubMed

Järvenpää, Marja; Lindström, Kai

2004-11-22

Eutrophication as a result of human activity has resulted in increased algal blooms and turbidity in aquatic environments. We investigated experimentally the effect of algal turbidity on the mating system and sexual selection in the sand goby, Pomatoschistus minutus (Pallas), a marine fish with a resource-defence mating system and paternal care. Owing to male-male competition and female choice, large males can monopolize multiple mates, while some males do not achieve mating at all. We show that the number of eggs laid was the same in both turbid and clear tanks but that mating success was more evenly distributed among males in turbid than in clear water. The opportunity for sexual selection was lower in turbid conditions. In turbid conditions mating success was less skewed towards large males. Our results suggest that increased turbidity can change mating systems and decrease the opportunity for sexual selection as well as selection intensity.

KSC-99pp0656

NASA Image and Video Library

1999-06-07

Under the watchful eyes of workers at Launch Pad 17A, Cape Canaveral Air Station (CCAS), the second stage of a Boeing Delta II rocket is lowered toward the first stage below. The first and second stages will be mated for the launch, targeted on June 23 at CCAS, , of NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. FUSE was developed by The Johns Hopkins University under contract to Goddard Space Flight Center, Greenbelt, Md., to investigate the origin and evolution of the lightest elements in the universe hydrogen and deuterium. In addition, the FUSE satellite will examine the forces and process involved in the evolution of the galaxies, stars and planetary systems by investigating light in the far ultraviolet portion of the electromagnetic spectrum

Differential investment in pre- vs. post-copulatory sexual selection reinforces a cross-continental reversal of sexual size dimorphism in Sepsis punctum (Diptera: Sepsidae).

PubMed

Puniamoorthy, Nalini; Blanckenhorn, W U; Schäfer, M A

2012-11-01

Theory predicts that males have a limited amount of resources to invest in reproduction, suggesting a trade-off between traits that enhance mate acquisition and those that enhance fertilization success. Here, we investigate the relationship between pre- and post-copulatory investment by comparing the mating behaviour and reproductive morphology of four European and five North American populations of the dung fly Sepsis punctum (Diptera) that display a reversal of sexual size dimorphism (SSD). We show that the geographic reversal in SSD between the continents (male biased in Europe, female biased in North America) is accompanied by differential investment in pre- vs. post-copulatory traits. We find higher remating rates in European populations, where larger males acquire more matings and consequently have evolved relatively larger testes and steeper hyper-allometry with body size. American populations, in sharp contrast, display much reduced, if any, effect of body size on those traits. Instead, North American males demonstrate an increased investment in mate acquisition prior to copulation, with more mounting attempts and a distinctive abdominal courtship display that is completely absent in Europe. When controlling for body size, relative female spermathecal size is similar on both continents, so we find no direct evidence for the co-evolution of male and female internal reproductive morphology. By comparing allopatric populations of the same species that apparently have evolved different mating systems and consequently SSD, we thus indirectly demonstrate differential investment in pre- vs. post-copulatory mechanisms increasing reproductive success. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Mate Choice in Soldier Beetles: Field & Laboratory Experiments that Demonstrate Sexual Selection in Action

ERIC Educational Resources Information Center

Eason, Perri K.; Sherman, Peter T.

2003-01-01

Although the theory of evolution is the foundation of modern biology, students too rarely have an opportunity to watch selection operate in natural populations of animals. This lack may be partially responsible for the unfortunate ignorance of many people regarding the significance of evolution in biology. Laboratory exercises that directly study…

Using theories of sexual selection and sexual conflict to improve our understanding of plant ecology and evolution

PubMed Central

Lankinen, Åsa; Karlsson Green, Kristina

2015-01-01

Today it is accepted that the theories of sexual selection and sexual conflict are general and can be applied to both animals and plants. However, potentially due to a controversial history, plant studies investigating sexual selection and sexual conflict are relatively rare. Moreover, these theories and concepts are seldom implemented in research fields investigating related aspects of plant ecology and evolution. Even though these theories are complex, and can be difficult to study, we suggest that several fields in plant biology would benefit from incorporating and testing the impact of selection pressures generated by sexual selection and sexual conflict. Here we give examples of three fields where we believe such incorporation would be particularly fruitful, including (i) mechanisms of pollen–pistil interactions, (ii) mating-system evolution in hermaphrodites and (iii) plant immune responses to pests and pathogens. PMID:25613227

Darwinism and the cultural evolution of sports.

PubMed

De Block, Andreas; Dewitte, Siegfried

2009-01-01

This article outlines a Darwinian approach to sports that takes into account its profoundly cultural character and thereby overcomes the traditional nature-culture dichotomies in the sociology of sport. We argue that there are good reasons to view sports as culturally evolved signaling systems that serve a function similar to (biological) courtship rituals in other animals. Our approach combines the insights of evolutionary psychology, which states that biological adaptations determine the boundaries for the types of sport that are possible, and pure cultural theories, which describe the mechanism of cultural evolution without referring to sport's biological bases. Several biological and cultural factors may moderate the direct effect that signaling value has on a sport's viability or popularity. Social learning underlies many aspects of the cultural control of sports, and sports have evolved new cultural functions more-or-less unrelated to mate choice as cultural evolution itself became important in humans.

Demography, environmental uncertainty, and the evolution of mate desertion in the snail kite

USGS Publications Warehouse

Beissinger, S.R.

1986-01-01

The Snail Kite (Rostrhamus sociabilis), an endangered hawk, has a unique mating system in Florida (Beissinger and Snyder 1987): when food is abundant, males or females desert their mates at nearly equal frequency (ambisexual mate desertion) in the midst of a nesting cycle. I examined the demographic and environmental constraints selecting for a clutch size that permits one parent to desert, yet optimizes the number of offspring produced by each parent. Demographic studies, conducted from 1979-1983, indicated that kites have (1) a very high nest failure rate (?= 68%) due most often to unstable nest sites and predation, (2) a variable nesting season (5-10 mo/yr), (3) an early age of first reproduction for a bird this size (10 mo), (4) a high degree of iteroparity (double and potentially triple clutching within a season), and (5) unstable populations. Both nesting success and population size were directly related to Everglades water levels and resultant snail densities. Kites responded to large annual changes in food abundance, not by adjusting clutch size but by deserting their mates and presumably attempting to renest. Kite demographic traits appear to be adaptations to or results of an uncertain environment. Based on 67 yr of Everglades water levels, environmental predictability, measured by spectral analysis and Colwell's (1974) index, was low and influenced by water management regimes: (1) water levels were lowered, (2) annual variation in levels increased and annual cycles became stronger, (3) the period length of long-term drought-flood cycles shifted from 10 or more yr toward 5 yr, and (4) levels became a less predictive cue for favorable nesting conditions. A potential evolutionary pathway from biparental care to mate desertion in Snail Kites is proposed. It is unlikely that mate desertion evolved solely from a context of conflict between the sexes, because kite nesting success is so low that it is probably maladaptive for a parent to desert and jeopardize the survival of any of its first brood. Instead, mate desertion behavior probably evolved in response to a smaller average clutch size; this would allow females to be highly iteroparous and avoid the costs of overinvestment, and should be strongly favored in a highly uncertain environment. Analysis of clutches in museum collections suggests that an apparent decline in clutch size may have occurred in Florida during the past century. The potential for ambisexual mate desertion to occur in other vertebrates is during the past century. The potential for ambisexual mate desertion to occur in other vertebrates is examined.

Dynamics of multiple infection and within-host competition by the anther-smut pathogen.

PubMed

Hood, M E

2003-07-01

Infection of one host by multiple pathogen genotypes represents an important area of pathogen ecology and evolution that lacks a broad empirical foundation. Multiple infection of Silene latifolia by Microbotryum violaceum was studied under field and greenhouse conditions using the natural polymorphism for mating-type bias as a marker. Field transmission resulted in frequent multiple infection, and each stem of the host was infected independently. Within-host diversity of infections equaled that of nearby inoculum sources by the end of the growing season. The number of diseased stems per plant was positively correlated with multiple infection and with overwintering mortality. As a result, multiply infected plants were largely purged from the population, and there was lower within-host pathogen diversity in the second season. However, among plants with a given number of diseased stems, multiply infected plants had a lower risk of overwintering mortality. Following simultaneous and sequential inoculation, strong competitive exclusion was demonstrated, and the first infection had a significant advantage. Dynamics of multiple infection initially included components of coinfection models for virulence evolution and then components of superinfection models after systemic colonization. Furthermore, there was evidence for an advantage of genotypes with mating-type bias, which may contribute to maintenance of this polymorphism in natural populations.

Evolution of hierarchical cytoplasmic inheritance in the plasmodial slime mold Physarum polycephalum.

PubMed

Iwanaga, Akiko; Sasaki, Akira

2004-04-01

A striking linear dominance relationship for uniparental mitochondrial transmission is known between many mating types of plasmodial slime mold Physarum polycephalum. We herein examine how such hierarchical cytoplasmic inheritance evolves in isogamous organisms with many self-incompatible mating types. We assume that a nuclear locus determines the mating type of gametes and that another nuclear locus controls the digestion of mitochondria DNAs (mtDNAs) of the recipient gamete after fusion. We then examine the coupled genetic dynamics for the evolution of self-incompatible mating types and biased mitochondrial transmission between them. In Physarum, a multiallelic nuclear locus matA controls both the mating type of the gametes and the selective elimination of the mtDNA in the zygotes. We theoretically examine two potential mechanisms that might be responsible for the preferential digestion of mitochondria in the zygote. In the first model, the preferential digestion of mitochondria is assumed to be the outcome of differential expression levels of a suppressor gene carried by each gamete (suppression-power model). In the second model (site-specific nuclease model), the digestion of mtDNAs is assumed to be due to their cleavage by a site-specific nuclease that cuts the mtDNA at unmethylated recognition sites. Also assumed is that the mtDNAs are methylated at the same recognition site prior to the fusion, thereby being protected against the nuclease of the same gamete, and that the suppressor alleles convey information for the recognition sequences of nuclease and methylase. In both models, we found that a linear dominance hierarchy evolves as a consequence of the buildup of a strong linkage disequilibrium between the mating-type locus and the suppressor locus, though it fails to evolve if the recombination rate between the two loci is larger than a threshold. This threshold recombination rate depends on the number of mating types and the degree of fitness reduction in the heteroplasmic zygotes. If the recombination rate is above the threshold, suppressor alleles are equally distributed in each mating type at evolutionary equilibrium. Based on the theoretical results of the site-specific nuclease model, we propose that a nested subsequence structure in the recognition sequence should underlie the linear dominance hierarchy of mitochondrial transmission.

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.

Raising Darwin's consciousness : Female sexuality and the prehominid origins of patriarchy.

PubMed

Hrdy, S B

1997-03-01

Sociobiologists and feminists agree that men in patriarchal social systems seek to control females, but sociobiologists go further, using Darwin's theory of sexual selection and Trivers's ideas on parental investment to explain why males should attempt to control female sexuality. From this perspective, the stage for the development under some conditions of patriarchal social systems was set over the course of primate evolution.Sexual selection encompasses both competition between males and female choice. But in applying this theory to our "lower origins" (prehominid ancestors), Darwin assumed that choices were made by essentially "coy" females. I argue here that female solicitation of multiple males (either simultaneously or sequentially, depending on the breeding system) characterized prehominid females; this prehominid legacy of cyclical sexual assertiveness, itself possibly a female counter-strategy to male efforts to control the timing of female reproduction, generated further male counter-strategies. This dialectic had important implications for emerging hominid mating systems, human evolution, and the development of patriarchal arrangements in some human societies. For hominid males who will invest in offspring, there would be powerful selection for emotions, behaviors, and customs that ensure them certainty of paternity. The sexual modesty that so struck Darwin can be explained as a recent evolved or learned (perhaps both) adaptation in women to avoid penalties imposed by patrilines on daughters and mates who failed to conform to the patriline's prevailing norms for their sex. Other supposedly innate universals, such as female preferences for wealthy husbands, are also likely to be facultative accommodations by women to constraints set up when patrilines monopolized resources needed by females to survive and reproduce, and passed on intergenerational control of these resources preferentially to sons.

Sexual reproduction and sex determination in green algae.

PubMed

Sekimoto, Hiroyuki

2017-05-01

The sexual reproductive processes of some representative freshwater green algae are reviewed. Chlamydomonas reinhardtii is a unicellular volvocine alga having two mating types: mating type plus (mt + ) and mating type minus (mt - ), which are controlled by a single, complex mating-type locus. Sexual adhesion between the gametes is mediated by sex-specific agglutinin molecules on their flagellar membranes. Cell fusion is initiated by an adhesive interaction between the mt + and mt - mating structures, followed by localized membrane fusion. The loci of sex-limited genes and the conformation of sex-determining regions have been rearranged during the evolution of volvocine algae; however, the essential function of the sex-determining genes of the isogamous unicellular Chlamydomonas reinhardtii is conserved in the multicellular oogamous Volvox carteri. The sexual reproduction of the unicellular charophycean alga, Closterium peracerosum-strigosum-littorale complex, is also focused on here. The sexual reproductive processes of heterothallic strains are controlled by two multifunctional sex pheromones, PR-IP and PR-IP Inducer, which independently promote multiple steps in conjugation at the appropriate times through different induction mechanisms. The molecules involved in sexual reproduction and sex determination have also been characterized.

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?

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.

Short-term exposure to a synthetic estrogen disrupts mating dynamics in a pipefish.

PubMed

Partridge, Charlyn; Boettcher, Anne; Jones, Adam G

2010-11-01

Sexual selection is responsible for the evolution of some of the most elaborate traits occurring in nature, many of which play a vital role in competition over access to mates and individual reproductive fitness. Because expression of these traits is typically regulated by sex-steroids there is a significant potential for their expression to be affected by the presence of certain pollutants, such as endocrine disrupting compounds. Endocrine disruptors have been shown to alter primary sexual traits and impact reproduction, but few studies have investigated how these compounds affect secondary sexual trait expression and how that may, in turn, impact mating dynamics. In this study we examine how short-term exposure to a synthetic estrogen impacts secondary sexual trait expression and mating dynamics in the Gulf pipefish, a species displaying sex-role reversal. Our results show that only 10days of exposure to 17α-ethinylestradiol results in adult male pipefish developing female-like secondary sexual traits. While these males are capable of reproduction, females discriminate against exposed males in mate choice trials. In natural populations, this type of discrimination would reduce male mating opportunities, thus potentially reducing their long-term reproductive success. Importantly, the effects of these compounds on mating dynamics and mating opportunity would not be observed using the current standard methods of assessing environmental contamination. However, disrupting these processes could have profound effects on the viability of exposed populations. Copyright © 2010 Elsevier Inc. All rights reserved.

Ultimate Drivers and Proximate Correlates of Polyandry in Predatory Mites

PubMed Central

Schausberger, Peter; Patiño-Ruiz, J. David; Osakabe, Masahiro; Murata, Yasumasa; Sugimoto, Naoya; Uesugi, Ryuji; Walzer, Andreas

2016-01-01

Polyandry is more widespread than anticipated from Bateman’s principle but its ultimate (evolutionary) causes and proximate (mechanistic) correlates are more difficult to pinpoint than those of polygyny. Here, we combined mating experiments, quantification of reproductive traits and microsatellite genotyping to determine the fitness implications of polyandry in two predatory mite species, where males are highly polygynous (up to 45 fertilized females during life), whereas females range from monandry to various polyandry levels. The medium-level polyandrous (up to eight male mates possible) Neoseiulus californicus received clear direct and indirect benefits: multiply mated females produced more offspring with higher survival chances over longer times than singly mated females. In contrast, singly and multiply mated females of the low-level polyandrous (commonly two male mates at maximum) Phytoseiulus persimilis produced similar numbers of offspring having similar survival chances. In both species, multiple mating resulted in mixed offspring paternities, opening the chance for indirect fitness benefits such as enhanced genetic compatibility, complementarity and/or variability. However, the female re-mating likelihood and the paternity chance of non-first male mates were lower in P. persimilis than in N. californicus. Regarding proximate factors, in both species first mating duration and female re-mating likelihood were negatively correlated. Based on occasional fertilization failure of first male mates in P. persimilis, and mixed offspring paternities in both species, we argue that fertilization assurance and the chance to gain indirect fitness benefits are the ultimate drivers of polyandry in P. persimilis, whereas those of N. californicus are higher offspring numbers coupled with enhanced offspring viability and possibly other indirect fitness benefits. Overall, the adaptive significance and proximate events well reflected the polyandry levels. Our study provides a key example for linking behavioral experiments, quantification of reproductive traits and paternity analysis via offspring genotyping to explain the evolution of differing levels of polyandry. PMID:27100395

Ultimate Drivers and Proximate Correlates of Polyandry in Predatory Mites.

PubMed

Schausberger, Peter; Patiño-Ruiz, J David; Osakabe, Masahiro; Murata, Yasumasa; Sugimoto, Naoya; Uesugi, Ryuji; Walzer, Andreas

2016-01-01

Polyandry is more widespread than anticipated from Bateman's principle but its ultimate (evolutionary) causes and proximate (mechanistic) correlates are more difficult to pinpoint than those of polygyny. Here, we combined mating experiments, quantification of reproductive traits and microsatellite genotyping to determine the fitness implications of polyandry in two predatory mite species, where males are highly polygynous (up to 45 fertilized females during life), whereas females range from monandry to various polyandry levels. The medium-level polyandrous (up to eight male mates possible) Neoseiulus californicus received clear direct and indirect benefits: multiply mated females produced more offspring with higher survival chances over longer times than singly mated females. In contrast, singly and multiply mated females of the low-level polyandrous (commonly two male mates at maximum) Phytoseiulus persimilis produced similar numbers of offspring having similar survival chances. In both species, multiple mating resulted in mixed offspring paternities, opening the chance for indirect fitness benefits such as enhanced genetic compatibility, complementarity and/or variability. However, the female re-mating likelihood and the paternity chance of non-first male mates were lower in P. persimilis than in N. californicus. Regarding proximate factors, in both species first mating duration and female re-mating likelihood were negatively correlated. Based on occasional fertilization failure of first male mates in P. persimilis, and mixed offspring paternities in both species, we argue that fertilization assurance and the chance to gain indirect fitness benefits are the ultimate drivers of polyandry in P. persimilis, whereas those of N. californicus are higher offspring numbers coupled with enhanced offspring viability and possibly other indirect fitness benefits. Overall, the adaptive significance and proximate events well reflected the polyandry levels. Our study provides a key example for linking behavioral experiments, quantification of reproductive traits and paternity analysis via offspring genotyping to explain the evolution of differing levels of polyandry.

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.

Mating Success, Longevity, and Fertility of Diabrotica virgifera virgifera LeConte (Chrysomelidae: Coleoptera) in Relation to Body Size and Cry3Bb1-Resistant and Cry3Bb1-Susceptible Genotypes

PubMed Central

French, Bryan Wade; Hammack, Leslie; Tallamy, Douglas W.

2015-01-01

Insect resistance to population control methodologies is a widespread problem. The development of effective resistance management programs is often dependent on detailed knowledge regarding the biology of individual species and changes in that biology associated with resistance evolution. This study examined the reproductive behavior and biology of western corn rootworm beetles of known body size from lines resistant and susceptible to the Cry3Bb1 protein toxin expressed in transgenic Bacillus thuringiensis maize. In crosses between, and within, the resistant and susceptible genotypes, no differences occurred in mating frequency, copulation duration, courtship duration, or fertility; however, females mated with resistant males showed reduced longevity. Body size did not vary with genotype. Larger males and females were not more likely to mate than smaller males and females, but larger females laid more eggs. Moderately strong, positive correlation occurred between the body sizes of successfully mated males and females; however, weak correlation also existed for pairs that did not mate. Our study provided only limited evidence for fitness costs associated with the Cry3Bb1-resistant genotype that might reduce the persistence in populations of the resistant genotype but provided additional evidence for size-based, assortative mating, which could favor the persistence of resistant genotypes affecting body size. PMID:26569315

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

Comparing pre- and post-copulatory mate competition using social network analysis in wild crickets

PubMed Central

Fisher, David N.; Rodríguez-Muñoz, Rolando

2016-01-01

Sexual selection results from variation in success at multiple stages in the mating process, including competition before and after mating. The relationship between these forms of competition, such as whether they trade-off or reinforce one another, influences the role of sexual selection in evolution. However, the relationship between these 2 forms of competition is rarely quantified in the wild. We used video cameras to observe competition among male field crickets and their matings in the wild. We characterized pre- and post-copulatory competition as 2 networks of competing individuals. Social network analysis then allowed us to determine 1) the effectiveness of precopulatory competition for avoiding postcopulatory competition, 2) the potential for divergent mating strategies, and 3) whether increased postcopulatory competition reduces the apparent reproductive benefits of male promiscuity. We found 1) limited effectiveness of precopulatory competition for avoiding postcopulatory competition; 2) males do not specifically engage in only 1 type of competition; and 3) promiscuous individuals tend to mate with each other, which will tend to reduce variance in reproductive success in the population and highlights the trade-off inherent in mate guarding. Our results provide novel insights into the works of sexual competition in the wild. Furthermore, our study demonstrates the utility of using network analyses to study competitive interactions, even in species lacking obvious social structure. PMID:27174599

Asymmetric mismatch in strain-specific genital morphology causes increased harm to Drosophila females.

PubMed

Masly, John P; Kamimura, Yoshitaka

2014-08-01

Although several evolutionary forces have been proposed to contribute to genital morphological diversification, it is unclear which might act early during the evolution of novel structural traits. We test the hypothesis that mismatch between interacting male and female secondary sexual structures gives rise to increased harm to females, consistent with the outcome predicted from a history of sexual conflict. We mate Drosophila sechellia females to males from a collection of D. mauritiana-D. sechellia interspecific genetic introgression lines that possess quantitative morphological variation in the posterior lobe of the genital arch, an external genital structure that can cause wounds to the female abdomen during mating. We find that males with smaller posterior lobes, and those that possess lobes with similarities in shape to D. mauritiana, cause more severe wounding compared to either D. sechellia males with strain-specific morphologies or introgression males that possess larger lobes or lobes with more pronounced D. sechellia features. These results suggest a possible history of sexual conflict during the evolution of the posterior lobe in D. sechellia, but also suggest a potential contribution of divergence in sensory recognition mechanisms to posterior lobe evolution. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Parasite transmission among relatives halts Red Queen dynamics.

PubMed

Greenspoon, Philip B; Mideo, Nicole

2017-03-01

The theory that coevolving hosts and parasites create a fluctuating selective environment for one another (i.e., produce Red Queen dynamics) has deep roots in evolutionary biology; yet empirical evidence for Red Queen dynamics remains scarce. Fluctuating coevolutionary dynamics underpin the Red Queen hypothesis for the evolution of sex, as well as hypotheses explaining the persistence of genetic variation under sexual selection, local parasite adaptation, the evolution of mutation rate, and the evolution of nonrandom mating. Coevolutionary models that exhibit Red Queen dynamics typically assume that hosts and parasites encounter one another randomly. However, if related individuals aggregate into family groups or are clustered spatially, related hosts will be more likely to encounter parasites transmitted by genetically similar individuals. Using a model that incorporates familial parasite transmission, we show that a slight degree of familial parasite transmission is sufficient to halt coevolutionary fluctuations. Our results predict that evidence for Red Queen dynamics, and its evolutionary consequences, are most likely to be found in biological systems in which hosts and parasites mix mainly at random, and are less likely to be found in systems with familial aggregation. This presents a challenge to the Red Queen hypothesis and other hypotheses that depend on coevolutionary cycling. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Correlated evolution of beak morphology and song in the neotropical woodcreeper radiation.

PubMed

Derryberry, Elizabeth Perrault; Seddon, Nathalie; Claramunt, Santiago; Tobias, Joseph Andrew; Baker, Adam; Aleixo, Alexandre; Brumfield, Robb Thomas

2012-09-01

Mating signals may diversify as a byproduct of morphological adaptation to different foraging niches, potentially driving speciation. Although many studies have focused on the direct influence of ecological and sexual selection on signal divergence, the role of indirect mechanisms remains poorly understood. Using phenotypic and molecular datasets, we explored the interplay between morphological and vocal evolution in an avian radiation characterized by dramatic beak variation, the Neotropical woodcreepers (Dendrocolaptinae). We found evidence of a trade-off between the rate of repetition of song syllables and frequency bandwidth: slow paced songs had either narrow or wide frequency bandwidths, and bandwidth decreased as song pace increased. This bounded phenotypic space for song structure supports the hypothesis that passerine birds face a motor constraint during song production. Diversification of acoustic characters within this bounded space was correlated with diversification of beak morphology. In particular, species with larger beaks produced slower songs with narrower frequency bandwidths, suggesting that ecological selection on beak morphology influences the diversification of woodcreeper songs. Because songs in turn mediate mate choice and species recognition in birds, these results indicate a broader role for ecology in avian diversification. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

The evolution of sexes: A specific test of the disruptive selection theory.

PubMed

da Silva, Jack

2018-01-01

The disruptive selection theory of the evolution of anisogamy posits that the evolution of a larger body or greater organismal complexity selects for a larger zygote, which in turn selects for larger gametes. This may provide the opportunity for one mating type to produce more numerous, small gametes, forcing the other mating type to produce fewer, large gametes. Predictions common to this and related theories have been partially upheld. Here, a prediction specific to the disruptive selection theory is derived from a previously published game-theoretic model that represents the most complete description of the theory. The prediction, that the ratio of macrogamete to microgamete size should be above three for anisogamous species, is supported for the volvocine algae. A fully population genetic implementation of the model, involving mutation, genetic drift, and selection, is used to verify the game-theoretic approach and accurately simulates the evolution of gamete sizes in anisogamous species. This model was extended to include a locus for gamete motility and shows that oogamy should evolve whenever there is costly motility. The classic twofold cost of sex may be derived from the fitness functions of these models, showing that this cost is ultimately due to genetic conflict.

The genetic architecture of sexual conflict: male harm and female resistance in Callosobruchus maculatus.

PubMed

Gay, L; Brown, E; Tregenza, T; Pincheira-Donoso, D; Eady, P E; Vasudev, R; Hunt, J; Hosken, D J

2011-02-01

Males harm females during mating in a range of species. This harm is thought to evolve because it is directly or indirectly beneficial to the male, despite being costly to his mate. The resulting sexually antagonistic selection can cause sexual arms races. For sexually antagonistic co-evolution to occur, there must be genetic variation for traits involved in female harming and susceptibility to harm, but even then intersexual genetic correlations could facilitate or impede sexual co-evolution. Male Callosobruchus maculatus harm their mates during copulation by damaging the female's reproductive tract. However, there have been no investigations of the genetic variation in damage or in female susceptibility to damage, nor has the genetic covariance between these characters been assessed. Here, we use a full-sib/half-sib breeding design to show that male damage is heritable, whereas female susceptibility to damage is much less so. There is also a substantial positive genetic correlation between the two, suggesting that selection favouring damaging males will increase the prevalence of susceptible females. We also provide evidence consistent with intralocus sexual conflict in this species. © 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

Humpback whale song: A new review

NASA Astrophysics Data System (ADS)

Frankel, Adam S.

2003-04-01

The humpback whale song has been described and investigated since the early 1970s. Much has been learned about the humpback whale social structure, but the understanding of the song and its function remains elusive. The hierarchical nature of the song structure was described early on: Songs can be sung for a long period, apparently by males, and primarily during the mating season. However, singers also become physically competitive, suggesting alternative mating strategies. There are a number of unique structural features of song. Its structure evolves over time and combination. The nature of song evolution strongly implies cultural transmission. Song structure appears to be shared within an entire population, even though there appears to be little interchange of individuals between sub populations. Despite over thirty years of inquiry there are still numerous unanswered questions: Why is the song structure so complex? Is song a sexual advertisement, an acoustic space mediation mechanism, or both? How do females choose mates, or do they? What drives song evolution, and why is there so much variation in the rate of change? Are there nonreproductive functions of song? What prompts a male to begin or end singing? Our current understanding and the outstanding questions yet to be answered will be reviewed.

Variation in mating systems of salamanders: mate guarding or territoriality?

PubMed

Deitloff, Jennifer; Alcorn, Michael A; Graham, Sean P

2014-07-01

Two of the most common mating tactics in vertebrates are mate guarding and territoriality, yet much of the research on these strategies has focused on mating systems in birds, despite novel insights gained from studying less traditional systems. North American stream salamanders that comprise the Eurycea bislineata complex represent an excellent nontraditional system for comparing mating strategies because these species exhibit a continuum of male morphologies, diverse habitat associations, and various potential mating strategies. We studied two species within this complex that exhibit the extremes of this continuum, Eurycea aquatica (robust morph) and Eurycea cirrigera (slender morph). The larger head in males of E. aquatica is due to larger musculature around the jaw and may be associated with aggressive behavior. Therefore, we hypothesized that the robust morphology exhibited by males of E. aquatica provides benefits during either territorial defense or mate defense and that males of E. cirrigera would not exhibit aggression in either scenario. We found that neither species exhibited aggressive behavior to defend a territory. However, in the presence of a female, males of E. aquatica were significantly more aggressive toward intruding males than were males of E. cirrigera. Therefore, mate-guarding behavior occurs in E. aquatica, and the enlarged head of males likely aids in deterring rivals. This is the first demonstration of mate-guarding behavior in a plethodontid, the most speciose family of salamanders. Copyright © 2014 Elsevier B.V. All rights reserved.

The relative importance of different direct benefits in the mate choices of a field cricket.

PubMed

Wagner, William E; Basolo, Alexandra L

2007-03-01

Discussions about the evolution of female mating preferences have often suggested that females should express multiple strong preferences when different male traits are correlated with different mating benefits, yet few studies have directly tested this hypothesis by comparing the strength of female preferences for male traits known to be correlated with different benefits. In the variable field cricket, Gryllus lineaticeps, females receive fecundity and fertility benefits from mating with males with higher chirp rates and life-span benefits from mating with males with longer chirp durations. Although females prefer higher chirp rates and longer chirp durations when the other trait is held constant, it is possible that they give priority to one of these song traits when both vary. In this study, we examined the relative importance of chirp rate and chirp duration in female mate choice using single-stimulus presentations of songs that varied in both chirp rate and chirp duration. Females expressed both directional and stabilizing preferences based on chirp rate, responding most strongly to a chirp rate approximately one standard deviation above the population mean. Females did not express preferences based on chirp duration, and did not express correlational preferences. These results suggest that females may give priority to the reproductive benefits provided by males that produce higher chirp rates.

Mate competition and evolutionary outcomes in genetically modified zebrafish (Danio rerio).

PubMed

Howard, Richard D; Rohrer, Karl; Liu, Yiyang; Muir, William M

2015-05-01

Demonstrating relationships between sexual selection mechanisms and trait evolution is central to testing evolutionary theory. Using zebrafish, we found that wild-type males possessed a significant advantage in mate competition over transgenic RFP Glofish® males. In mating trials, wild-type males were aggressively superior to transgenic males in male-male chases and male-female chases; as a result, wild-type males sired 2.5× as many young as did transgenic males. In contrast, an earlier study demonstrated that female zebrafish preferred transgenic males as mates when mate competition was excluded experimentally. We tested the evolutionary consequence of this conflict between sexual selection mechanisms in a long-term study. The predicted loss of the transgenic phenotype was confirmed. More than 18,500 adults collected from 18 populations across 15 generations revealed that the frequency of the transgenic phenotype declined rapidly and was eliminated entirely in all but one population. Fitness component data for both sexes indicated that only male mating success differed between wild-type and transgenic individuals. Our predictive demographic model based on fitness components closely matched the rate of transgenic phenotype loss observed in the long-term study, thereby supporting its utility for studies assessing evolutionary outcomes of escaped or released genetically modified animals. © 2015 The Author(s).

The significance of multiple mating in the social wasp Vespula maculifrons.

PubMed

Goodisman, Michael A D; Kovacs, Jennifer L; Hoffman, Eric A

2007-09-01

The evolution of the complex societies displayed by social insects depended partly on high relatedness among interacting group members. Therefore, behaviors that depress group relatedness, such as multiple mating by reproductive females (polyandry), are unexpected in social insects. Nevertheless, the queens of several social insect species mate multiply, suggesting that polyandry provides some benefits that counteract the costs. However, few studies have obtained evidence for links between rates of polyandry and fitness in naturally occurring social insect populations. We investigated if polyandry was beneficial in the social wasp Vespula maculifrons. We used genetic markers to estimate queen mate number in V. maculifrons colonies and assessed colony fitness by counting the number of cells that colonies produced. Our results indicated that queen mate number was directly, strongly, and significantly correlated with the number of queen cells produced by colonies. Because V. maculifrons queens are necessarily reared in queen cells, our results demonstrate that high levels of polyandry are associated with colonies capable of producing many new queens. These data are consistent with the explanation that polyandry is adaptive in V. maculifrons because it provides a fitness advantage to queens. Our research may provide a rare example of an association between polyandry and fitness in a natural social insect population and help explain why queens in this taxon mate multiply.

Wind of change: new insights on the ecology and evolution of pollination and mating in wind-pollinated plants.

PubMed

Friedman, Jannice; Barrett, Spencer C H

2009-06-01

The rich literature that characterizes the field of pollination biology has focused largely on animal-pollinated plants. At least 10 % of angiosperms are wind pollinated, and this mode of pollination has evolved on multiple occasions among unrelated lineages, and hence this discrepancy in research interest is surprising. Here, the evolution and functional ecology of pollination and mating in wind-pollinated plants are discussed, a theoretical framework for modelling the selection of wind pollination is outlined, and pollen capture and the occurrence of pollen limitation in diverse wind-pollinated herbs are investigated experimentally. Wind pollination may commonly evolve to provide reproductive assurance when pollinators are scarce. Evidence is presented that pollen limitation in wind-pollinated plants may not be as common as it is in animal-pollinated species. The studies of pollen capture in wind-pollinated herbs demonstrate that pollen transfer efficiency is not substantially lower than in animal-pollinated plants as is often assumed. These findings challenge the explanation that the evolution of few ovules in wind-pollinated flowers is associated with low pollen loads. Floral and inflorescence architecture is crucial to pollination and mating because of the aerodynamics of wind pollination. Evidence is provided for the importance of plant height, floral position, and stamen and stigma characteristics in promoting effective pollen dispersal and capture. Finally, it is proposed that geitonogamous selfing may alleviate pollen limitation in many wind-pollinated plants with unisexual flowers.

Wind of change: new insights on the ecology and evolution of pollination and mating in wind-pollinated plants

PubMed Central

Friedman, Jannice; Barrett, Spencer C. H.

2009-01-01

Background The rich literature that characterizes the field of pollination biology has focused largely on animal-pollinated plants. At least 10 % of angiosperms are wind pollinated, and this mode of pollination has evolved on multiple occasions among unrelated lineages, and hence this discrepancy in research interest is surprising. Here, the evolution and functional ecology of pollination and mating in wind-pollinated plants are discussed, a theoretical framework for modelling the selection of wind pollination is outlined, and pollen capture and the occurrence of pollen limitation in diverse wind-pollinated herbs are investigated experimentally. Scope and Conclusions Wind pollination may commonly evolve to provide reproductive assurance when pollinators are scarce. Evidence is presented that pollen limitation in wind-pollinated plants may not be as common as it is in animal-pollinated species. The studies of pollen capture in wind-pollinated herbs demonstrate that pollen transfer efficiency is not substantially lower than in animal-pollinated plants as is often assumed. These findings challenge the explanation that the evolution of few ovules in wind-pollinated flowers is associated with low pollen loads. Floral and inflorescence architecture is crucial to pollination and mating because of the aerodynamics of wind pollination. Evidence is provided for the importance of plant height, floral position, and stamen and stigma characteristics in promoting effective pollen dispersal and capture. Finally, it is proposed that geitonogamous selfing may alleviate pollen limitation in many wind-pollinated plants with unisexual flowers. PMID:19218583

A Method to Test the Effect of Environmental Cues on Mating Behavior in Drosophila melanogaster.

PubMed

Gorter, Jenke A; Billeter, Jean-Christophe

2017-07-17

An individual's sexual drive is influenced by genotype, experience and environmental conditions. How these factors interact to modulate sexual behaviors remains poorly understood. In Drosophila melanogaster, environmental cues, such as food availability, affect mating activity offering a tractable system to investigate the mechanisms modulating sexual behavior. In D. melanogaster, environmental cues are often sensed via the chemosensory gustatory and olfactory systems. Here, we present a method to test the effect of environmental chemical cues on mating behavior. The assay consists of a small mating arena containing food medium and a mating couple. The mating frequency for each couple is continuously monitored for 24 h. Here we present the applicability of this assay to test environmental compounds from an external source through a pressurized air system as well as manipulation of the environmental components directly in the mating arena. The use of a pressurized air system is especially useful to test the effect of very volatile compounds, while manipulating components directly in the mating arena can be of value to ascertain a compound's presence. This assay can be adapted to answer questions about the influence of genetic and environmental cues on mating behavior and fecundity as well as other male and female reproductive behaviors.

[DNA Extraction from Old Bones by AutoMate Express™ System].

PubMed

Li, B; Lü, Z

2017-08-01

To establish a method for extracting DNA from old bones by AutoMate Express™ system. Bones were grinded into powder by freeze-mill. After extraction by AutoMate Express™, DNA were amplified and genotyped by Identifiler®Plus and MinFiler™ kits. DNA were extracted from 10 old bone samples, which kept in different environments with the postmortem interval from 10 to 20 years, in 3 hours by AutoMate Express™ system. Complete STR typing results were obtained from 8 samples. AutoMate Express™ system can quickly and efficiently extract DNA from old bones, which can be applied in forensic practice. Copyright© by the Editorial Department of Journal of Forensic Medicine

Reticulate evolution and the human past: an anthropological perspective.

PubMed

Winder, Isabelle C; Winder, Nick P

2014-01-01

The evidence is mounting that reticulate (web-like) evolution has shaped the biological histories of many macroscopic plants and animals, including non-human primates closely related to Homo sapiens, but the implications of this non-hierarchical evolution for anthropological enquiry are not yet fully understood. When they are understood, the result may be a paradigm shift in evolutionary anthropology. This paper reviews the evidence for reticulated evolution in the non-human primates and human lineage. Then it makes the case for extrapolating this sort of patterning to Homo sapiens and other hominins and explores the implications this would have for research design, method and understandings of evolution in anthropology. Reticulation was significant in human evolutionary history and continues to influence societies today. Anthropologists and human scientists-whether working on ancient or modern populations-thus need to consider the implications of non-hierarchic evolution, particularly where molecular clocks, mathematical models and simplifying assumptions about evolutionary processes are used. This is not just a problem for palaeoanthropology. The simple fact of different mating systems among modern human groups, for example, may demand that more attention is paid to the potential for complexity in human genetic and cultural histories.

Inbreeding depression in an insect with maternal care: influences of family interactions, life stage and offspring sex.

PubMed

Meunier, J; Kölliker, M

2013-10-01

Although inbreeding is commonly known to depress individual fitness, the severity of inbreeding depression varies considerably across species. Among the factors contributing to this variation, family interactions, life stage and sex of offspring have been proposed, but their joint influence on inbreeding depression remains poorly understood. Here, we demonstrate that these three factors jointly shape inbreeding depression in the European earwig, Forficula auricularia. Using a series of cross-breeding, split-clutch and brood size manipulation experiments conducted over two generations, we first showed that sib mating (leading to inbred offspring) did not influence the reproductive success of earwig parents. Second, the presence of tending mothers and the strength of sibling competition (i.e. brood size) did not influence the expression of inbreeding depression in the inbred offspring. By contrast, our results revealed that inbreeding dramatically depressed the reproductive success of inbred adult male offspring, but only had little effect on the reproductive success of inbred adult female offspring. Overall, this study demonstrates limited effects of family interactions on inbreeding depression in this species and emphasizes the importance of disentangling effects of sib mating early and late during development to better understand the evolution of mating systems and population dynamics. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

The influence of developmental environment on courtship song in cactophilic Drosophila.

PubMed

Iglesias, Patricia P; Soto, Eduardo M; Soto, Ignacio M; Colines, Betina; Hasson, Esteban

2018-04-15

Closely related species often differ in the signals involved in sexual communication and mate recognition. Determining the factors influencing signal quality (i.e. signal's content and conspicuousness) provides an important insight into the potential pathways by which these interspecific differences evolve. Host specificity could bias the direction of the evolution of sexual communication and the mate recognition system, favouring sensory channels that work best in the different host conditions. In this study, we focus on the cactophilic sibling species Drosophila buzzatii and D. koepferae that have diverged not only in the sensory channel used for sexual communication and mate recognition but also in the cactus species that use as primary hosts. We evaluate the role of the developmental environment in generating courtship song variation using an isofemale line design. Our results show that host environment during development induces changes in the courtship song of D. koepferae males, but not in D. buzzatii males. Moreover, we report for the first time that host rearing environment affects the conspicuousness of courtship song (i.e. song volume). Our results are mainly discussed in the context of the sensory drive hypothesis. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

Divergent mating patterns and a unique mode of external sperm transfer in Zoraptera: an enigmatic group of pterygote insects

NASA Astrophysics Data System (ADS)

Dallai, R.; Gottardo, M.; Mercati, D.; Machida, R.; Mashimo, Y.; Matsumura, Y.; Beutel, R. G.

2013-06-01

A remarkable external sperm transfer is described for the first time in a species of a group of winged insects (Pterygota), the enigmatic Zoraptera. Mating and sperm transfer of two species of the order were examined in detail, documented, and compared with each other and with patterns described for other species belonging to the order. The behavior differs strikingly in Zorotypus impolitus and Zorotypus magnicaudelli. A copula is performed by males and females of the latter, as it is also the case in other zorapteran species and generally in pterygote insects. In striking contrast to this, males of Z. impolitus do not copulate but deposit small (100 μm in diameter) spermatophores externally on the abdomen of the female. Each spermatophore contains only one giant spermatozoon (3 mm long and 3 μm wide), a unique feature in the entire Hexapoda. External sperm transfer in Pterygota is a highly unusual case of evolutionary reversal. The very small relict group Zoraptera displays a uniform general morphology but exhibits very different reproductive structures and patterns of mating behavior. This may be an extreme form of a more general situation in insects, with a specific form of selection resulting in an accelerated rate of evolution in the reproductive system.

Continuous and discontinuous phase transitions in the evolution of a polygenic trait under stabilizing selective pressure

NASA Astrophysics Data System (ADS)

Fierro, Annalisa; Cocozza, Sergio; Monticelli, Antonella; Scala, Giovanni; Miele, Gennaro

2017-06-01

The presence of phenomena analogous to phase transition in Statistical Mechanics has been suggested in the evolution of a polygenic trait under stabilizing selection, mutation and genetic drift. By using numerical simulations of a model system, we analyze the evolution of a population of N diploid hermaphrodites in random mating regime. The population evolves under the effect of drift, selective pressure in form of viability on an additive polygenic trait, and mutation. The analysis allows to determine a phase diagram in the plane of mutation rate and strength of selection. The involved pattern of phase transitions is characterized by a line of critical points for weak selective pressure (smaller than a threshold), whereas discontinuous phase transitions, characterized by metastable hysteresis, are observed for strong selective pressure. A finite-size scaling analysis suggests the analogy between our system and the mean-field Ising model for selective pressure approaching the threshold from weaker values. In this framework, the mutation rate, which allows the system to explore the accessible microscopic states, is the parameter controlling the transition from large heterozygosity ( disordered phase) to small heterozygosity ( ordered one).

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.

Stochastic modelling of shifts in allele frequencies reveals a strongly polygynous mating system in the re-introduced Asiatic wild ass.

PubMed

Renan, Sharon; Greenbaum, Gili; Shahar, Naama; Templeton, Alan R; Bouskila, Amos; Bar-David, Shirli

2015-04-01

Small populations are prone to loss of genetic variation and hence to a reduction in their evolutionary potential. Therefore, studying the mating system of small populations and its potential effects on genetic drift and genetic diversity is of high importance for their viability assessments. The traditional method for studying genetic mating systems is paternity analysis. Yet, as small populations are often rare and elusive, the genetic data required for paternity analysis are frequently unavailable. The endangered Asiatic wild ass (Equus hemionus), like all equids, displays a behaviourally polygynous mating system; however, the level of polygyny has never been measured genetically in wild equids. Combining noninvasive genetic data with stochastic modelling of shifts in allele frequencies, we developed an alternative approach to paternity analysis for studying the genetic mating system of the re-introduced Asiatic wild ass in the Negev Desert, Israel. We compared the shifts in allele frequencies (as a measure of genetic drift) that have occurred in the wild ass population since re-introduction onset to simulated scenarios under different proportions of mating males. We revealed a strongly polygynous mating system in which less than 25% of all males participate in the mating process each generation. This strongly polygynous mating system and its potential effect on the re-introduced population's genetic diversity could have significant consequences for the long-term persistence of the population in the Negev. The stochastic modelling approach and the use of allele-frequency shifts can be further applied to systems that are affected by genetic drift and for which genetic data are limited. © 2015 John Wiley & Sons Ltd.

Honey bee queens do not count mates to assess their mating success

USDA-ARS?s Scientific Manuscript database

The mating system of honey bees (genus Apis) is extremely polyandrous, where reproductive females (queens) typically mate with 12 or more males (drones) during their mating flight(s). The evolutionary implications for hyperpolyandry have been subject to considerable debate and empirical testing beca...

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.

Surviving in sympatry: paragenital divergence and sexual mimicry between a pair of traumatically inseminating plant bugs.

PubMed

Tatarnic, Nikolai J; Cassis, Gerasimos

2013-10-01

Reproductive interactions between species can carry significant costs (e.g., wasted time, energy, and gametes). In traumatically inseminating insects, heterospecific mating costs may be intensified, with indiscriminate mating and damaging genitalia leading to damage or death. When closely related traumatically inseminating species are sympatric, we predict selection should favor the rapid evolution of reproductive isolation. Here we report on a cryptic species of traumatically inseminating plant bug, Coridromius taravao, living sympatrically with its sister species, Coridromius tahitiensis, in French Polynesia. Despite their sister-species relationship, they exhibit striking differences in reproductive morphology, with females of each species stabbed and inseminated through different parts of their abdomens. Furthermore, C. tahitiensis is sexually dimorphic in coloration and vestiture, while both sexes of C. taravao share the C. tahitiensis male expression of these traits. These findings support a role for (1) reproductive character divergence and (2) interspecies sexual mimicry in limiting interspecific mating brought about by indiscriminate male mating behavior.

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.

Optical panel system including stackable waveguides

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeSanto, Leonard; Veligdan, James T.

An optical panel system including stackable waveguides is provided. The optical panel system displays a projected light image and comprises a plurality of planar optical waveguides in a stacked state. The optical panel system further comprises a support system that aligns and supports the waveguides in the stacked state. In one embodiment, the support system comprises at least one rod, wherein each waveguide contains at least one hole, and wherein each rod is positioned through a corresponding hole in each waveguide. In another embodiment, the support system comprises at least two opposing edge structures having the waveguides positioned therebetween, whereinmore » each opposing edge structure contains a mating surface, wherein opposite edges of each waveguide contain mating surfaces which are complementary to the mating surfaces of the opposing edge structures, and wherein each mating surface of the opposing edge structures engages a corresponding complementary mating surface of the opposite edges of each waveguide.« less

Optical panel system including stackable waveguides

DOEpatents

DeSanto, Leonard; Veligdan, James T.

2007-03-06

An optical panel system including stackable waveguides is provided. The optical panel system displays a projected light image and comprises a plurality of planar optical waveguides in a stacked state. The optical panel system further comprises a support system that aligns and supports the waveguides in the stacked state. In one embodiment, the support system comprises at least one rod, wherein each waveguide contains at least one hole, and wherein each rod is positioned through a corresponding hole in each waveguide. In another embodiment, the support system comprises at least two opposing edge structures having the waveguides positioned therebetween, wherein each opposing edge structure contains a mating surface, wherein opposite edges of each waveguide contain mating surfaces which are complementary to the mating surfaces of the opposing edge structures, and wherein each mating surface of the opposing edge structures engages a corresponding complementary mating surface of the opposite edges of each waveguide.

The persistence of facultative parthenogenesis in Drosophila albomicans.

PubMed

Chang, Chia-chen; Ting, Chau-Ti; Chang, Ching-Ho; Fang, Shu; Chang, Hwei-yu

2014-01-01

Parthenogenesis has evolved independently in more than 10 Drosophila species. Most cases are tychoparthenogenesis, which is occasional or accidental parthenogenesis in normally bisexual species with a low hatching rate of eggs produced by virgin females; this form is presumed to be an early stage of parthenogenesis. To address how parthenogenesis and sexual reproduction coexist in Drosophila populations, we investigated several reproductive traits, including the fertility, parthenogenetic capability, diploidization mechanisms, and mating propensity of parthenogenetic D. albomicans. The fertility of mated parthenogenetic females was significantly higher than that of virgin females. The mated females could still produce parthenogenetic offspring but predominantly produced offspring by sexual reproduction. Both mated parthenogenetic females and their parthenogenetic-sexual descendants were capable of parthenogenesis. The alleles responsible for parthenogenesis can be propagated through both parthenogenesis and sexual reproduction. As diploidy is restored predominantly by gamete duplication, heterozygosity would be very low in parthenogenetic individuals. Hence, genetic variation in parthenogenetic genomes would result from sexual reproduction. The mating propensity of females after more than 20 years of isolation from males was decreased. If mutations reducing mating propensities could occur under male-limited conditions in natural populations, decreased mating propensity might accelerate tychoparthenogenesis through a positive feedback mechanism. This process provides an opportunity for the evolution of obligate parthenogenesis. Therefore, the persistence of facultative parthenogenesis may be an adaptive reproductive strategy in Drosophila when a few founders colonize a new niche or when small populations are distributed at the edge of a species' range, consistent with models of geographical parthenogenesis.

The Persistence of Facultative Parthenogenesis in Drosophila albomicans

PubMed Central

Chang, Ching-Ho; Fang, Shu; Chang, Hwei-yu

2014-01-01

Parthenogenesis has evolved independently in more than 10 Drosophila species. Most cases are tychoparthenogenesis, which is occasional or accidental parthenogenesis in normally bisexual species with a low hatching rate of eggs produced by virgin females; this form is presumed to be an early stage of parthenogenesis. To address how parthenogenesis and sexual reproduction coexist in Drosophila populations, we investigated several reproductive traits, including the fertility, parthenogenetic capability, diploidization mechanisms, and mating propensity of parthenogenetic D. albomicans. The fertility of mated parthenogenetic females was significantly higher than that of virgin females. The mated females could still produce parthenogenetic offspring but predominantly produced offspring by sexual reproduction. Both mated parthenogenetic females and their parthenogenetic-sexual descendants were capable of parthenogenesis. The alleles responsible for parthenogenesis can be propagated through both parthenogenesis and sexual reproduction. As diploidy is restored predominantly by gamete duplication, heterozygosity would be very low in parthenogenetic individuals. Hence, genetic variation in parthenogenetic genomes would result from sexual reproduction. The mating propensity of females after more than 20 years of isolation from males was decreased. If mutations reducing mating propensities could occur under male-limited conditions in natural populations, decreased mating propensity might accelerate tychoparthenogenesis through a positive feedback mechanism. This process provides an opportunity for the evolution of obligate parthenogenesis. Therefore, the persistence of facultative parthenogenesis may be an adaptive reproductive strategy in Drosophila when a few founders colonize a new niche or when small populations are distributed at the edge of a species' range, consistent with models of geographical parthenogenesis. PMID:25415200

Convenience polyandry or convenience polygyny? Costly sex under female control in a promiscuous primate.

PubMed

Huchard, Elise; Canale, Cindy I; Le Gros, Chloé; Perret, Martine; Henry, Pierre-Yves; Kappeler, Peter M

2012-04-07

Classic sex roles depict females as choosy, but polyandry is widespread. Empirical attempts to understand the evolution of polyandry have often focused on its adaptive value to females, whereas 'convenience polyandry' might simply decrease the costs of sexual harassment. We tested whether constraint-free female strategies favour promiscuity over mating selectivity through an original experimental design. We investigated variation in mating behaviour in response to a reversible alteration of sexual dimorphism in body mass in the grey mouse lemur, a small primate where female brief sexual receptivity allows quantifying polyandry. We manipulated body condition in captive females, predicting that convenience polyandry would increase when females are weaker than males, thus less likely to resist their solicitations. Our results rather support the alternative hypothesis of 'adaptive polyandry': females in better condition are more polyandrous. Furthermore, we reveal that multiple mating incurs significant energetic costs, which are strikingly symmetrical between the sexes. Our study shows that mouse lemur females exert tight control over mating and actively seek multiple mates. The benefits of remating are nevertheless not offset by its costs in low-condition females, suggesting that polyandry is a flexible strategy yielding moderate fitness benefits in this small mammal.

Convenience polyandry or convenience polygyny? Costly sex under female control in a promiscuous primate

PubMed Central

Huchard, Elise; Canale, Cindy I.; Le Gros, Chloé; Perret, Martine; Henry, Pierre-Yves; Kappeler, Peter M.

2012-01-01

Classic sex roles depict females as choosy, but polyandry is widespread. Empirical attempts to understand the evolution of polyandry have often focused on its adaptive value to females, whereas ‘convenience polyandry’ might simply decrease the costs of sexual harassment. We tested whether constraint-free female strategies favour promiscuity over mating selectivity through an original experimental design. We investigated variation in mating behaviour in response to a reversible alteration of sexual dimorphism in body mass in the grey mouse lemur, a small primate where female brief sexual receptivity allows quantifying polyandry. We manipulated body condition in captive females, predicting that convenience polyandry would increase when females are weaker than males, thus less likely to resist their solicitations. Our results rather support the alternative hypothesis of ‘adaptive polyandry’: females in better condition are more polyandrous. Furthermore, we reveal that multiple mating incurs significant energetic costs, which are strikingly symmetrical between the sexes. Our study shows that mouse lemur females exert tight control over mating and actively seek multiple mates. The benefits of remating are nevertheless not offset by its costs in low-condition females, suggesting that polyandry is a flexible strategy yielding moderate fitness benefits in this small mammal. PMID:21976684

Cryptic forcible insemination: male snakes exploit female physiology, anatomy, and behavior to obtain coercive matings.

PubMed

Shine, Richard; Langkilde, Tracy; Mason, Robert T

2003-11-01

Whether males can inseminate uncooperative females is a central determinant of mating system evolution that profoundly affects the interpretation of phenomena such as multiple mating by females, mate choice, reproductive seasonality, and courtship tactics. Forcible insemination is usually inferred from direct physical battles between the sexes and has been dismissed on intuitive grounds for many kinds of animals. For example, snakes have elongate flexible bodies (making it difficult for a male to restrain a female physically), males are typically smaller than females, and copulation requires female cloacal gaping to enable intromission. Male garter snakes (Thamnophis sirtalis) do not display any overt aggression during courtship and simply lie over the female and exhibit rhythmic pulsating caudocephalic waves of muscular contraction; previous studies have interpreted this behavior as a mechanism for eliciting female receptivity. In contrast, we show that male garter snakes forcibly inseminate females. They do so by taking advantage of specific features of snake physiology, respiratory anatomy, and antipredator behavior. The snake lung extends along most of the body, with the large posterior section (the saccular lung) lacking any respiratory exchange surface. Rhythmic caudocephalic waves by courting male garter snakes push anoxic air from the saccular lung forward and across the respiratory surfaces such that females cannot obtain oxygen. Their stress response involves cloacal gaping, which functions in other contexts to repel predators by extruding feces and musk but in this situation permits male intromission. Thus, superficially benign courtship behaviors may involve cryptic coercion even in species for which intuition dismisses any possibility of forcible insemination.

Male sexual ornament size is positively associated with reproductive morphology and enhanced fertility in the stalk-eyed fly Teleopsis dalmanni

PubMed Central

2008-01-01

Background Exaggerated male ornaments and displays often evolve in species where males only provide females with ejaculates during reproduction. Although "good genes" arguments are typically invoked to explain this phenomenon, a simpler alternative is possible if variation in male reproductive quality (e.g. sperm number, ejaculate content, mating rate) is an important determinant of female reproductive success. The "phenotype-linked fertility hypothesis" states that female preference for male ornaments or displays has been selected to ensure higher levels of fertility and has driven the evolution of exaggerated male traits. Females of the stalk-eyed fly Teleopsis dalmanni must mate frequently to maintain high levels of fertility and prefer to mate with males exhibiting large eyespan, a condition-dependent sexual ornament. If eyespan indicates male reproductive quality, females could directly increase their reproductive success by mating with males with large eyespan. Here we investigate whether male eyespan indicates accessory gland and testis length, and then ask whether mating with large eyespan males affects female fertility. Results Male eyespan was a better predictor of two key male reproductive traits – accessory gland and testis length – than was body size alone. This positive relationship held true over three levels of increasing environmental stress during the maturation of the adult accessory glands and testes. Furthermore, females housed with a large eyespan male exhibited higher levels of fertility than those with small eyespan males. Conclusion Male eyespan in stalk-eyed flies is subject to strong directional mate preference and is a reliable indicator of male reproductive quality – both because males with larger eyespan have bigger accessory glands and testes, and also as they confer higher fertility on females. Fertility enhancement may have arisen because males with larger eyespan mated more often and/or because they transferred more sperm or other substances per ejaculate. The need to ensure high levels of fertility could thus have been an important selective force in the coevolution of female preference and male eyespan in stalk-eyed flies. Our results support the phenotype-linked fertility hypothesis and suggest that it might be of general importance in explaining the evolution of exaggerated male ornaments and displays in species where males only provide females with ejaculates during reproduction. PMID:18710553

Male sexual ornament size is positively associated with reproductive morphology and enhanced fertility in the stalk-eyed fly Teleopsis dalmanni.

PubMed

Rogers, David W; Denniff, Matthew; Chapman, Tracey; Fowler, Kevin; Pomiankowski, Andrew

2008-08-18

Exaggerated male ornaments and displays often evolve in species where males only provide females with ejaculates during reproduction. Although "good genes" arguments are typically invoked to explain this phenomenon, a simpler alternative is possible if variation in male reproductive quality (e.g. sperm number, ejaculate content, mating rate) is an important determinant of female reproductive success. The "phenotype-linked fertility hypothesis" states that female preference for male ornaments or displays has been selected to ensure higher levels of fertility and has driven the evolution of exaggerated male traits. Females of the stalk-eyed fly Teleopsis dalmanni must mate frequently to maintain high levels of fertility and prefer to mate with males exhibiting large eyespan, a condition-dependent sexual ornament. If eyespan indicates male reproductive quality, females could directly increase their reproductive success by mating with males with large eyespan. Here we investigate whether male eyespan indicates accessory gland and testis length, and then ask whether mating with large eyespan males affects female fertility. Male eyespan was a better predictor of two key male reproductive traits--accessory gland and testis length--than was body size alone. This positive relationship held true over three levels of increasing environmental stress during the maturation of the adult accessory glands and testes. Furthermore, females housed with a large eyespan male exhibited higher levels of fertility than those with small eyespan males. Male eyespan in stalk-eyed flies is subject to strong directional mate preference and is a reliable indicator of male reproductive quality--both because males with larger eyespan have bigger accessory glands and testes, and also as they confer higher fertility on females. Fertility enhancement may have arisen because males with larger eyespan mated more often and/or because they transferred more sperm or other substances per ejaculate. The need to ensure high levels of fertility could thus have been an important selective force in the coevolution of female preference and male eyespan in stalk-eyed flies. Our results support the phenotype-linked fertility hypothesis and suggest that it might be of general importance in explaining the evolution of exaggerated male ornaments and displays in species where males only provide females with ejaculates during reproduction.

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.

Evolutionary Genomics of Peach and Almond Domestication

PubMed Central

Velasco, Dianne; Hough, Josh; Aradhya, Mallikarjuna; Ross-Ibarra, Jeffrey

2016-01-01

The domesticated almond [Prunus dulcis (L.) Batsch] and peach [P. persica (Mill.) D. A. Webb] originated on opposite sides of Asia and were independently domesticated ∼5000 yr ago. While interfertile, they possess alternate mating systems and differ in a number of morphological and physiological traits. Here, we evaluated patterns of genome-wide diversity in both almond and peach to better understand the impacts of mating system, adaptation, and domestication on the evolution of these taxa. Almond has around seven times the genetic diversity of peach, and high genome-wide FST values support their status as separate species. We estimated a divergence time of ∼8 MYA (million years ago), coinciding with an active period of uplift in the northeast Tibetan Plateau and subsequent Asian climate change. We see no evidence of a bottleneck during domestication of either species, but identify a number of regions showing signatures of selection during domestication and a significant overlap in candidate regions between peach and almond. While we expected gene expression in fruit to overlap with candidate selected regions, instead we find enrichment for loci highly differentiated between the species, consistent with recent fossil evidence suggesting fruit divergence long preceded domestication. Taken together, this study tells us how closely related tree species evolve and are domesticated, the impact of these events on their genomes, and the utility of genomic information for long-lived species. Further exploration of this data will contribute to the genetic knowledge of these species and provide information regarding targets of selection for breeding application, and further the understanding of evolution in these species. PMID:27707802

Inbreeding avoidance under different null models of random mating in the great tit.

PubMed

Szulkin, Marta; Zelazowski, Przemyslaw; Nicholson, George; Sheldon, Ben C

2009-07-01

1. In populations where inbreeding causes a substantial decrease in fitness, selection is expected to favour the evolution of inbreeding avoidance behaviours. Elsewhere we have documented substantial inbreeding depression and the importance of dispersal in avoiding inbreeding in a long-term population study of the great tit Parus major in Wytham (UK). In this study, we ask whether individuals from this population actively avoid mating with kin. 2. We generated four contrasting models of random mate choice that assumed varying levels of mate availability in each year of the data set. This allowed us to compare observed and simulated distributions and frequencies of inbreeding coefficients from 41 years of breeding data. 3. We found no evidence that birds avoid mating with related partners. Our results show that birds breed more often with relatives than expected under null models of mate choice that lack population structure, but not when compared to scenarios where birds were mated with their nearest neighbours. Pedigree-derived F(IS) values were positive for all scenarios of random mating, confirming the lack of inbreeding avoidance in this population. 4. These results imply the existence of spatial genetic structure where related individuals occur closer together than nonrelated individuals while breeding, and suggest that the relatedness between breeding individuals of the opposite sex decreases with distance. Thus, while dispersal from the natal site decreases the number of relatives around an individual, it does not completely homogenize genetic structure. 5. We show that brother-sister pairs are observed more often than under any scenario of random mating, suggesting that not only birds do not avoid mating with kin, but also that the apparently maladaptive choice of mating with a sibling is made more often than expected. 6. Our results provide no evidence to suggest that individuals actively avoid kin. In fact, some types of inbreeding occur more often than expected, despite the substantial fitness costs. The observed lack of inbreeding avoidance is in agreement with other studies of non-cooperatively breeding passerine birds, although the higher than expected frequency of sibling mating remains a puzzling result.

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.

Mosquito biology. Evolution of sexual traits influencing vectorial capacity in anopheline mosquitoes.

PubMed

Mitchell, Sara N; Kakani, Evdoxia G; South, Adam; Howell, Paul I; Waterhouse, Robert M; Catteruccia, Flaminia

2015-02-27

The availability of genome sequences from 16 anopheline species provides unprecedented opportunities to study the evolution of reproductive traits relevant for malaria transmission. In Anopheles gambiae, a likely candidate for sexual selection is male 20-hydroxyecdysone (20E). Sexual transfer of this steroid hormone as part of a mating plug dramatically changes female physiological processes intimately tied to vectorial capacity. By combining phenotypic studies with ancestral state reconstructions and phylogenetic analyses, we show that mating plug transfer and male 20E synthesis are both derived characters that have coevolved in anophelines, driving the adaptation of a female 20E-interacting protein that promotes oogenesis via mechanisms also favoring Plasmodium survival. Our data reveal coevolutionary dynamics of reproductive traits between the sexes likely to have shaped the ability of anophelines to transmit malaria. Copyright © 2015, American Association for the Advancement of Science.

Drosophila pachea asymmetric lobes are part of a grasping device and stabilize one-sided mating.

PubMed

Rhebergen, Flor T; Courtier-Orgogozo, Virginie; Dumont, Julien; Schilthuizen, Menno; Lang, Michael

2016-09-01

Multiple animal species exhibit morphological asymmetries in male genitalia. In insects, left-right genital asymmetries evolved many times independently and have been proposed to appear in response to changes in mating position. However, little is known about the relationship between mating position and the interaction of male and female genitalia during mating, and functional analyses of asymmetric morphologies in genitalia are virtually non-existent. We investigated the relationship between mating position, asymmetric genital morphology and genital coupling in the fruit fly Drosophila pachea, in which males possess an asymmetric pair of external genital lobes and mate in an unusual right-sided position on top of the female. We examined D. pachea copulation by video recording and by scanning electron microscopy of genital complexes. We observed that the interlocking of male and female genital organs in D. pachea is remarkably different from genital coupling in the well-studied D. melanogaster. In D. pachea, the female oviscapt valves are asymmetrically twisted during copulation. The male's asymmetric lobes tightly grasp the female's abdomen in an asymmetric 'locking' position, with the left and right lobes contacting different female structures. The male anal plates, which grasp the female genitalia in D. melanogaster, do not contact the female in D. pachea. Experimental lobe amputation by micro-surgery and laser-ablation of lobe bristles led to aberrant coupling of genitalia and variable mating positions, in which the male was tilted towards the right side of the female. We describe, for the first time, how the mating position depends on coupling of male and female genitalia in a species with asymmetric genitalia and one-sided mating position. Our results show that D. pachea asymmetric epandrial lobes do not act as a compensatory mechanism for the change from symmetric to one-sided mating position that occurred during evolution of D. pachea's ancestors, but as holding devices with distinct specialized functions on the left and right sides.

Genetic covariance between components of male reproductive success: within-pair vs. extra-pair paternity in song sparrows

PubMed Central

Reid, J M; Arcese, P; Losdat, S

2014-01-01

The evolutionary trajectories of reproductive systems, including both male and female multiple mating and hence polygyny and polyandry, are expected to depend on the additive genetic variances and covariances in and among components of male reproductive success achieved through different reproductive tactics. However, genetic covariances among key components of male reproductive success have not been estimated in wild populations. We used comprehensive paternity data from socially monogamous but genetically polygynandrous song sparrows (Melospiza melodia) to estimate additive genetic variance and covariance in the total number of offspring a male sired per year outside his social pairings (i.e. his total extra-pair reproductive success achieved through multiple mating) and his liability to sire offspring produced by his socially paired female (i.e. his success in defending within-pair paternity). Both components of male fitness showed nonzero additive genetic variance, and the estimated genetic covariance was positive, implying that males with high additive genetic value for extra-pair reproduction also have high additive genetic propensity to sire their socially paired female's offspring. There was consequently no evidence of a genetic or phenotypic trade-off between male within-pair paternity success and extra-pair reproductive success. Such positive genetic covariance might be expected to facilitate ongoing evolution of polygyny and could also shape the ongoing evolution of polyandry through indirect selection. PMID:25186454

Homage to Bateman: sex roles predict sex differences in sexual selection.

PubMed

Fritzsche, Karoline; Arnqvis, Göran

2013-07-01

Classic sex role theory predicts that sexual selection should be stronger in males in taxa showing conventional sex roles and stronger in females in role reversed mating systems. To test this very central prediction and to assess the utility of different measures of sexual selection, we estimated sexual selection in both sexes in four seed beetle species with divergent sex roles using a novel experimental design. We found that sexual selection was sizeable in females and the strength of sexual selection was similar in females and males in role-reversed species. Sexual selection was overall significantly stronger in males than in females and residual selection formed a substantial component of net selection in both sexes. Furthermore, sexual selection in females was stronger in role-reversed species compared to species with conventional sex roles. Variance-based measures of sexual selection (the Bateman gradient and selection opportunities) were better predictors of sexual dimorphism in reproductive behavior and morphology across species compared to trait-based measures (selection differentials). Our results highlight the importance of using assays that incorporate components of fitness manifested after mating. We suggest that the Bateman gradient is generally the most informative measure of the strength of sexual selection in comparisons across sexes and/or species. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Loaded transducer for downhole drilling components

DOEpatents

Hall, David R [Provo, UT; Fox, Joe [Spanish Fork, UT; Daly, Jeffery E [Cypress, TX

2009-05-05

A system for transmitting information between downhole components has a first downhole component with a first mating surface and a second downhole component having a second mating surface configured to substantially mate with the first mating surface. The system also has a first transmission element with a first communicating surface and is mounted within a recess in the first mating surface. The first transmission element also has an angled surface. The recess has a side with multiple slopes for interacting with the angled surface, each slope exerting a different spring force on the first transmission element. A second transmission element has a second communicating surface mounted proximate the second mating surface and adapted to communicate with the first communicating surface.

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.

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

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.

CULTURAL INHERITANCE OF SONG AND ITS ROLE IN THE EVOLUTION OF DARWIN'S FINCHES.

PubMed

Grant, B Rosemary; Grant, Peter R

1996-12-01

Songs of Darwin's finches were studied on the Galápagos Island of Daphne Major from 1976 to 1995. A single, structurally simple, and unvarying song is sung throughout life by each male of the two common species, Geospiza fortis (medium ground finch) and G. scandens (cactus finch). Songs of the two species differ strongly in quantitative features, and individual variation among males is much broader in G. fortis than in G. scandens. Although there are exceptions, songs of sons strongly resemble the songs of their fathers. They also resemble the songs of their paternal grandfathers, but not their maternal grandfathers, indicating that they are culturally inherited and not genetically inherited. Female G. fortis display a tendency to avoid mating with males that sing the same type of song as their father. They also avoid mating with males that sing heterospecific song, with very rare exceptions. Thus song, an evolving, culturally inherited trait, is an important factor in species recognition and mate choice. It constrains the mating of females to conspecifics, even when there is no genetic penalty to interbreeding, and thus may play a crucial role in species formation by promoting genetic isolation on secondary contact. The barrier is leaky in that occasional errors in song transmission result in misimprinting, which leads to a low incidence of hybridization and introgression. Introgression slows the rate of postzygotic isolation, but can produce individuals in novel genetic and morphological space that can provide the starting point of a new evolutionary trajectory. © 1996 The Society for the Study of Evolution.

BATEMANATER: a computer program to estimate and bootstrap mating system variables based on Bateman's principles.

PubMed

Jones, Adam G

2015-11-01

Bateman's principles continue to play a major role in the characterization of genetic mating systems in natural populations. The modern manifestations of Bateman's ideas include the opportunity for sexual selection (i.e. I(s) - the variance in relative mating success), the opportunity for selection (i.e. I - the variance in relative reproductive success) and the Bateman gradient (i.e. β(ss) - the slope of the least-squares regression of reproductive success on mating success). These variables serve as the foundation for one convenient approach for the quantification of mating systems. However, their estimation presents at least two challenges, which I address here with a new Windows-based computer software package called BATEMANATER. The first challenge is that confidence intervals for these variables are not easy to calculate. BATEMANATER solves this problem using a bootstrapping approach. The second, more serious, problem is that direct estimates of mating system variables from open populations will typically be biased if some potential progeny or adults are missing from the analysed sample. BATEMANATER addresses this problem using a maximum-likelihood approach to estimate mating system variables from incompletely sampled breeding populations. The current version of BATEMANATER addresses the problem for systems in which progeny can be collected in groups of half- or full-siblings, as would occur when eggs are laid in discrete masses or offspring occur in pregnant females. BATEMANATER has a user-friendly graphical interface and thus represents a new, convenient tool for the characterization and comparison of genetic mating systems. © 2015 John Wiley & Sons Ltd.

Sex Pheromone Evolution Is Associated with Differential Regulation of the Same Desaturase Gene in Two Genera of Leafroller Moths

PubMed Central

Albre, Jérôme; Liénard, Marjorie A.; Sirey, Tamara M.; Schmidt, Silvia; Tooman, Leah K.; Carraher, Colm; Greenwood, David R.; Löfstedt, Christer; Newcomb, Richard D.

2012-01-01

Chemical signals are prevalent in sexual communication systems. Mate recognition has been extensively studied within the Lepidoptera, where the production and recognition of species-specific sex pheromone signals are typically the defining character. While the specific blend of compounds that makes up the sex pheromones of many species has been characterized, the molecular mechanisms underpinning the evolution of pheromone-based mate recognition systems remain largely unknown. We have focused on two sets of sibling species within the leafroller moth genera Ctenopseustis and Planotortrix that have rapidly evolved the use of distinct sex pheromone blends. The compounds within these blends differ almost exclusively in the relative position of double bonds that are introduced by desaturase enzymes. Of the six desaturase orthologs isolated from all four species, functional analyses in yeast and gene expression in pheromone glands implicate three in pheromone biosynthesis, two Δ9-desaturases, and a Δ10-desaturase, while the remaining three desaturases include a Δ6-desaturase, a terminal desaturase, and a non-functional desaturase. Comparative quantitative real-time PCR reveals that the Δ10-desaturase is differentially expressed in the pheromone glands of the two sets of sibling species, consistent with differences in the pheromone blend in both species pairs. In the pheromone glands of species that utilize (Z)-8-tetradecenyl acetate as sex pheromone component (Ctenopseustis obliquana and Planotortrix octo), the expression levels of the Δ10-desaturase are significantly higher than in the pheromone glands of their respective sibling species (C. herana and P. excessana). Our results demonstrate that interspecific sex pheromone differences are associated with differential regulation of the same desaturase gene in two genera of moths. We suggest that differential gene regulation among members of a multigene family may be an important mechanism of molecular innovation in sex pheromone evolution and speciation. PMID:22291612

Female Genitalia Concealment Promotes Intimate Male Courtship in a Water Strider

PubMed Central

Han, Chang S.; Jablonski, Piotr G.

2009-01-01

Violent coercive mating initiation is typical for animals with sexual conflict over mating. In these species, the coevolutionary arms-race between female defenses against coercive mating and male counter-adaptations for increased mating success leads to coevolutionary chases of male and female traits that influence the mating. It has been controversial whether one of the sexes can evolve traits that allow them to “win” this arms race. Here, we use morphological analysis (traditional and scanning electron micrographs), laboratory experiments and comparative methods to show how females of a species characterized by typical coercive mating initiation appear to “win” a particular stage of the sexual conflict by evolving morphology to hide their genitalia from direct, forceful access by males. In an apparent response to the female morphological adaptation, males of this species added to their typically violent coercive mounting of the female new post-mounting, pre-copulatory courtship signals produced by tapping the water's surface with the mid-legs. These courtship signals are intimate in the sense that they are aimed at the female, on whom the male is already mounted. Females respond to the signals by exposing their hidden genitalia for copulatory intromission. Our results indicate that the apparent victory of coevolutionary arms race by one sex in terms of morphology may trigger evolution of a behavioral phenotype in the opposite sex. PMID:19516886

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

Genetic versus census estimators of the opportunity for sexual selection in the wild.

PubMed

Dunn, Stacey J; Waits, Lisette P; Byers, John A

2012-04-01

Abstract The existence of a direct link between intensity of sexual selection and mating-system type is widely accepted. However, the quantification of sexual selection has proven problematic. Several measures of sexual selection have been proposed, including the operational sex ratio (OSR), the breeding sex ratio (BSR), and the opportunity for sexual selection (I(mates)). For a wild population of pronghorn (Antilocapra americana), we calculated OSR and BSR. We estimated I(mates) from census data on the spatial and temporal distribution of receptive females in rut and from a multigenerational genetic pedigree. OSR and BSR indicated weak sexual selection on males, but census and pedigree I(mates) suggested stronger sexual selection on males than on females. OSR and BSR correlated with census but not pedigree estimates of I(mates), and census I(mates) did not correlate with pedigree estimates. This suggests that the behavioral mating system, as deduced from the spatial and temporal distribution of females, does not predict the genetic mating system of pronghorn. The differences we observed between estimators were primarily due to female mate sampling and choice and to the sex ratio. For most species, behavioral data are not perfectly accurate and therefore will be an insufficient alternative to using multigenerational pedigrees to quantify sexual selection.

Mate-Selection Systems and Criteria: Variation according to Family Structure.

ERIC Educational Resources Information Center

Lee, Gary R.; Stone, Lorene Hemphill

1980-01-01

Autonomous mate selection based on romantic attraction is more likely to be institutionalized in societies with nuclear family systems. Neolocal residence customs increase the probability that mate selection is autonomous but decrease the probability that it is based on romantic attraction. (Author)

Constrained evolution of the sex comb in Drosophila simulans.

PubMed

Maraqa, M S; Griffin, R; Sharma, M D; Wilson, A J; Hunt, J; Hosken, D J; House, C M

2017-02-01

Male fitness is dependent on sexual traits that influence mate acquisition (precopulatory sexual selection) and paternity (post-copulatory sexual selection), and although many studies have documented the form of selection in one or the other of these arenas, fewer have done it for both. Nonetheless, it appears that the dominant form of sexual selection is directional, although theoretically, populations should converge on peaks in the fitness surface, where selection is stabilizing. Many factors, however, can prevent populations from reaching adaptive peaks. Genetic constraints can be important if they prevent the development of highest fitness phenotypes, as can the direction of selection if it reverses across episodes of selection. In this study, we examine the evidence that these processes influence the evolution of the multivariate sex comb morphology of male Drosophila simulans. To do this, we conduct a quantitative genetic study together with a multivariate selection analysis to infer how the genetic architecture and selection interact. We find abundant genetic variance and covariance in elements of the sex comb. However, there was little evidence for directional selection in either arena. Significant nonlinear selection was detected prior to copulation when males were mated to nonvirgin females, and post-copulation during sperm offence (again with males mated to nonvirgins). Thus, contrary to our predictions, the evolution of the D. simulans sex comb is limited neither by genetic constraints nor by antagonistic selection between pre- and post-copulatory arenas, but nonlinear selection on the multivariate phenotype may prevent sex combs from evolving to reach some fitness maximizing optima. © 2016 The Authors. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Tracing the first step to speciation: ecological and genetic differentiation of a salamander population in a small forest.

PubMed

Steinfartz, Sebastian; Weitere, Markus; Tautz, Diethard

2007-11-01

Mechanisms and processes of ecologically driven adaptive speciation are best studied in natural situations where the splitting process is still occurring, i.e. before complete reproductive isolation is achieved. Here, we present a case of an early stage of adaptive differentiation under sympatric conditions in the fire salamander, Salamandra salamandra, that allows inferring the underlying processes for the split. Larvae of S. salamandra normally mature in small streams until metamorphosis, but in an old, continuous forest area near Bonn (the Kottenforst), we found salamander larvae not only in small streams but also in shallow ponds, which are ecologically very different from small streams. Common-environment experiments with larvae from both habitat types reveal specific adaptations to these different ecological conditions. Mitochondrial and microsatellite analyses show that the two ecologically differentiated groups also show signs of genetic differentiation. A parallel analysis of animals from a neighbouring much larger forest area (the Eifel), in which larvae mature only in streams, shows no signs of genetic differentiation, indicating that gene flow between ecologically similar types can occur over large distances. Hence, geographical factors cannot explain the differential larval habitat adaptations in the Kottenforst, in particular since adult life and mating of S. salamandra is strictly terrestrial and not associated with larval habitats. We propose therefore that the evolution of these adaptations was coupled with the evolution of cues for assortative mating which would be in line with models of sympatric speciation that suggest a co-evolution of habitat adaptations and associated mating signals.

Evolution of female multiple mating: A quantitative model of the “sexually selected sperm” hypothesis

PubMed Central

Bocedi, Greta; Reid, Jane M

2015-01-01

Explaining the evolution and maintenance of polyandry remains a key challenge in evolutionary ecology. One appealing explanation is the sexually selected sperm (SSS) hypothesis, which proposes that polyandry evolves due to indirect selection stemming from positive genetic covariance with male fertilization efficiency, and hence with a male's success in postcopulatory competition for paternity. However, the SSS hypothesis relies on verbal analogy with “sexy-son” models explaining coevolution of female preferences for male displays, and explicit models that validate the basic SSS principle are surprisingly lacking. We developed analogous genetically explicit individual-based models describing the SSS and “sexy-son” processes. We show that the analogy between the two is only partly valid, such that the genetic correlation arising between polyandry and fertilization efficiency is generally smaller than that arising between preference and display, resulting in less reliable coevolution. Importantly, indirect selection was too weak to cause polyandry to evolve in the presence of negative direct selection. Negatively biased mutations on fertilization efficiency did not generally rescue runaway evolution of polyandry unless realized fertilization was highly skewed toward a single male, and coevolution was even weaker given random mating order effects on fertilization. Our models suggest that the SSS process is, on its own, unlikely to generally explain the evolution of polyandry. PMID:25330405

Fluctuating environments, sexual selection and the evolution of flexible mate choice in birds.

PubMed

Botero, Carlos A; Rubenstein, Dustin R

2012-01-01

Environmentally-induced fluctuation in the form and strength of natural selection can drive the evolution of morphology, physiology, and behavior. Here we test the idea that fluctuating climatic conditions may also influence the process of sexual selection by inducing unexpected reversals in the relative quality or sexual attractiveness of potential breeding partners. Although this phenomenon, known as 'ecological cross-over', has been documented in a variety of species, it remains unclear the extent to which it has driven the evolution of major interspecific differences in reproductive behavior. We show that after controlling for potentially influential life history and demographic variables, there are significant positive associations between the variability and predictability of annual climatic cycles and the prevalence of infidelity and divorce within populations of a taxonomically diverse array of socially monogamous birds. Our results are consistent with the hypothesis that environmental factors have shaped the evolution of reproductive flexibility and suggest that in the absence of severe time constraints, secondary mate choice behaviors can help prevent, correct, or minimize the negative consequences of ecological cross-overs. Our findings also illustrate how a basic evolutionary process like sexual selection is susceptible to the increasing variability and unpredictability of climatic conditions that is resulting from climate change.

Female penis, male vagina, and their correlated evolution in a cave insect.

PubMed

Yoshizawa, Kazunori; Ferreira, Rodrigo L; Kamimura, Yoshitaka; Lienhard, Charles

2014-05-05

Sex-specific elaborations are common in animals and have attracted the attention of many biologists, including Darwin [1]. It is accepted that sexual selection promotes the evolution of sex-specific elaborations. Due to the faster replenishment rate of gametes, males generally have higher potential reproductive and optimal mating rates than females. Therefore, sexual selection acts strongly on males [2], leading to the rapid evolution and diversification of male genitalia [3]. Male genitalia are sometimes used as devices for coercive holding of females as a result of sexual conflict over mating [4, 5]. In contrast, female genitalia are usually simple. Here we report the reversal of intromittent organs in the insect genus Neotrogla (Psocodea: Prionoglarididae) from Brazilian caves. Females have a highly elaborate, penis-like structure, the gynosome, while males lack an intromittent organ. The gynosome has species-specific elaborations, such as numerous spines that fit species-specific pouches in the simple male genital chamber. During prolonged copulation (~40-70 hr), a large and potentially nutritious ejaculate is transferred from the male via the gynosome. The correlated genital evolution in Neotrogla is probably driven by reversed sexual selection with females competing for seminal gifts. Nothing similar is known among sex-role reversed animals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sexual selection targets cetacean pelvic bones

PubMed Central

Dines, J. P.; Otárola-Castillo, E.; Ralph, P.; Alas, J.; Daley, T.; Smith, A. D.; Dean, M. D.

2014-01-01

Male genitalia evolve rapidly, probably as a result of sexual selection. Whether this pattern extends to the internal infrastructure that influences genital movements remains unknown. Cetaceans (whales and dolphins) offer a unique opportunity to test this hypothesis: since evolving from land-dwelling ancestors, they lost external hind limbs and evolved a highly reduced pelvis which seems to serve no other function except to anchor muscles that maneuver the penis. Here we create a novel morphometric pipeline to analyze the size and shape evolution of pelvic bones from 130 individuals (29 species) in the context of inferred mating system. We present two main findings: 1) males from species with relatively intense sexual selection (inferred by relative testes size) have evolved relatively large penises and pelvic bones compared to their body size, and 2) pelvic bone shape diverges more quickly in species pairs that have diverged in inferred mating system. Neither pattern was observed in the anterior-most pair of vertebral ribs, which served as a negative control. This study provides evidence that sexual selection can affect internal anatomy that controls male genitalia. These important functions may explain why cetacean pelvic bones have not been lost through evolutionary time. PMID:25186496

Delayed maturation, neoteny, and social system differences in two manakins of the genus Chiroxiphia

USGS Publications Warehouse

Foster, M.S.

1987-01-01

Long-tailed manakins (Chiroxiphia linearis) and swallow-tailed manakins (C. caudata) are closely related, sexually dichromatic, lek-breeding species in which male mating success is highly skewed. Males of both species delay plumage maturation. Before reaching the definitive state, they wear a sequence of feather coats less conspicuous than that of the adult. Nondefinitive plumages probably enhance male survival in the two species; in C. caudata they may also enhance breeding success of young males, who may be fully reproductively mature their first year. In C. linearis testicular development is retarded along with that of plumage, although males may be physiologically capable of breeding prior to the acquisition of the definitive plumage. This difference probably reflects differences in the social systems of the two species. Five hypotheses have been proposed to explain the evolution of delayed plumage maturation. The sexual-selection, crypticbreeder, and winter-adaptation hypotheses suggest that it functions primarily to enhance survival of young males. The juvenile- and female-mimicry hypotheses emphasize enhancement of immediate mating success. Support is provided for all but the female-mimicry hypothesis; it is argued that data are more consistent with juvenile mimicry and a neotenic origin of nondefinitive plumages.

The influence of mating system on the intensity of parent-offspring conflict in primates.

PubMed

Long, T A F

2005-05-01

An evolutionary conflict of interest exists between parents and their offspring over the partitioning of parental investment (PI) among siblings. When the direct fitness benefits to offspring of increased PI, outweigh the inclusive fitness costs from lost future sibling fitness, selection should favour the evolution of offspring selfishness over altruism. In theory, this conflict is heightened when females are not strictly monogamous, as current offspring should be less altruistic towards future half-siblings than they would be towards full-siblings. Using data collected on foetal growth rate (representing prenatal PI) in primates, I test the prediction from theory that the resolution of the parent-offspring conflict will be closer to the offspring's evolutionary optima in polyandrous species than in more monandrous species. Using phylogenetic comparative analysis, and controlling for allometry, I show that offspring are able to obtain more PI when the probability of future full-siblings decreases, and that this is most pronounced in taxa where there is the opportunity for direct foetal access to the maternal bloodstream. These results support the hypothesis that the resolution of prenatal PI conflict is influenced by both a species' mating system and by its placental structure.

When Love Meets Money: Priming the Possession of Money Influences Mating Strategies.

PubMed

Li, Yi Ming; Li, Jian; Chan, Darius K-S; Zhang, Bo

2016-01-01

Money is an important factor that influences the development of romantic relationships. The current paper examines how the feeling of having relatively more or less money influences human mating strategies in long-term and short-term mating contexts under the framework of evolutionary psychology. We recruited mainland Chinese college students involved in steady, heterosexual romantic relationships to participate in two experiments. In each study, we experimentally triggered participants' feelings of having relatively more or less money and then examined their thoughts and behaviors related to mating. Results of Study 1 showed that men who were primed to feel that they had relatively more money were less satisfied with their partners' physical attractiveness than those primed to feel that they had less money, suggesting that the subjective feeling of having more or less money may affect men's preferences regarding the physical appearance of a mate in a long-term relationship. Interestingly, this difference was not significant for women. Results of Study 2 indicated that both men and women who were primed to feel that they had relatively more money exhibited a greater "behavioral approach tendency" toward an attractive member of the opposite sex than those primed to feel that they had less money. This finding suggests that people who feel they have relatively more money may have more interest in an attractive alternative than those who feel they have relatively less money. The differences in mating strategies between and within the genders brought about by money support the evolutionary hypothesis that individuals adopt conditional mating strategies in response to environmental conditions. Additionally, the results of experimental studies provide evidence for the causal effects of money on mating strategies. These findings have both conceptual and practical implications for the psychology of evolution and romantic relationships.

When Love Meets Money: Priming the Possession of Money Influences Mating Strategies

PubMed Central

Li, Yi Ming; Li, Jian; Chan, Darius K.-S.; Zhang, Bo

2016-01-01

Money is an important factor that influences the development of romantic relationships. The current paper examines how the feeling of having relatively more or less money influences human mating strategies in long-term and short-term mating contexts under the framework of evolutionary psychology. We recruited mainland Chinese college students involved in steady, heterosexual romantic relationships to participate in two experiments. In each study, we experimentally triggered participants' feelings of having relatively more or less money and then examined their thoughts and behaviors related to mating. Results of Study 1 showed that men who were primed to feel that they had relatively more money were less satisfied with their partners' physical attractiveness than those primed to feel that they had less money, suggesting that the subjective feeling of having more or less money may affect men's preferences regarding the physical appearance of a mate in a long-term relationship. Interestingly, this difference was not significant for women. Results of Study 2 indicated that both men and women who were primed to feel that they had relatively more money exhibited a greater “behavioral approach tendency” toward an attractive member of the opposite sex than those primed to feel that they had less money. This finding suggests that people who feel they have relatively more money may have more interest in an attractive alternative than those who feel they have relatively less money. The differences in mating strategies between and within the genders brought about by money support the evolutionary hypothesis that individuals adopt conditional mating strategies in response to environmental conditions. Additionally, the results of experimental studies provide evidence for the causal effects of money on mating strategies. These findings have both conceptual and practical implications for the psychology of evolution and romantic relationships. PMID:27047415

The role of sexual selection and conflict in mediating among-population variation in mating strategies and sexually dimorphic traits in Sepsis punctum.

PubMed

Dmitriew, Caitlin; Blanckenhorn, Wolf U

2012-01-01

The black scavenger fly Sepsis punctum exhibits striking among-population variation in the direction and magnitude of sexual size dimorphism, modification to the male forelimb and pre-copulatory behaviour. In some populations, male-biased sexual size dimorphism is observed; in other, less dimorphic, populations males court prior to mating. Such variation in reproductive traits is of interest to evolutionary biologists because it has the potential to limit gene flow among populations, contributing to speciation. Here, we investigate whether large male body size and modified forefemur are associated with higher male mating success within populations, whether these traits are associated with higher mating success among populations, and if these traits carry viability costs that could constrain their response to sexual selection. Flies from five distinct populations were reared at high or low food, generating high and low quality males. The expression of body size, forelimb morphology and courtship rate were each greater at high food, but high food males experienced higher mating success or reduced latency to first copulation in only one of the populations. Among populations, overall mating success increased with the degree of male-bias in overall body size and forelimb modification, suggesting that these traits have evolved as a means of increasing male mating rate. The increased mating success observed in large-male populations raises the question of why variation in magnitude of dimorphism persists among populations. One reason may be that costs of producing a large size constrain the evolution of ever-larger males. We found no evidence that juvenile mortality under food stress was greater for large-male populations, but development time was considerably longer and may represent an important constraint in an ephemeral and competitive growth environment.

Mating Changes Sexually Dimorphic Gene Expression in the Seed Beetle Callosobruchus maculatus.

PubMed

Immonen, Elina; Sayadi, Ahmed; Bayram, Helen; Arnqvist, Göran

2017-03-01

Sexually dimorphic phenotypes arise largely from sex-specific gene expression, which has mainly been characterized in sexually naïve adults. However, we expect sexual dimorphism in transcription to be dynamic and dependent on factors such as reproductive status. Mating induces many behavioral and physiological changes distinct to each sex and is therefore expected to activate regulatory changes in many sex-biased genes. Here, we first characterized sexual dimorphism in gene expression in Callosobruchus maculatus seed beetles. We then examined how females and males respond to mating and how it affects sex-biased expression, both in sex-limited (abdomen) and sex-shared (head and thorax) tissues. Mating responses were largely sex-specific and, as expected, females showed more genes responding compared with males (∼2,000 vs. ∼300 genes in the abdomen, ∼500 vs. ∼400 in the head and thorax, respectively). Of the sex-biased genes present in virgins, 16% (1,041 genes) in the abdomen and 17% (243 genes) in the head and thorax altered their relative expression between the sexes as a result of mating. Sex-bias status changed in 2% of the genes in the abdomen and 4% in the head and thorax following mating. Mating responses involved de-feminization of females and, to a lesser extent, de-masculinization of males relative to their virgin state: mating decreased rather than increased dimorphic expression of sex-biased genes. The fact that regulatory changes of both types of sex-biased genes occurred in both sexes suggests that male- and female-specific selection is not restricted to male- and female-biased genes, respectively, as is sometimes assumed. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Penis size interacts with body shape and height to influence male attractiveness.

PubMed

Mautz, Brian S; Wong, Bob B M; Peters, Richard A; Jennions, Michael D

2013-04-23

Compelling evidence from many animal taxa indicates that male genitalia are often under postcopulatory sexual selection for characteristics that increase a male's relative fertilization success. There could, however, also be direct precopulatory female mate choice based on male genital traits. Before clothing, the nonretractable human penis would have been conspicuous to potential mates. This observation has generated suggestions that human penis size partly evolved because of female choice. Here we show, based upon female assessment of digitally projected life-size, computer-generated images, that penis size interacts with body shape and height to determine male sexual attractiveness. Positive linear selection was detected for penis size, but the marginal increase in attractiveness eventually declined with greater penis size (i.e., quadratic selection). Penis size had a stronger effect on attractiveness in taller men than in shorter men. There was a similar increase in the positive effect of penis size on attractiveness with a more masculine body shape (i.e., greater shoulder-to-hip ratio). Surprisingly, larger penis size and greater height had almost equivalent positive effects on male attractiveness. Our results support the hypothesis that female mate choice could have driven the evolution of larger penises in humans. More broadly, our results show that precopulatory sexual selection can play a role in the evolution of genital traits.

Genetic Variation and Its Reflection on Posttranslational Modifications in Frequency Clock and Mating Type a-1 Proteins in Sordaria fimicola

PubMed Central

Arif, Rabia; Akram, Faiza; Jamil, Tazeen; Lee, Siu Fai

2017-01-01

Posttranslational modifications (PTMs) occur in all essential proteins taking command of their functions. There are many domains inside proteins where modifications take place on side-chains of amino acids through various enzymes to generate different species of proteins. In this manuscript we have, for the first time, predicted posttranslational modifications of frequency clock and mating type a-1 proteins in Sordaria fimicola collected from different sites to see the effect of environment on proteins or various amino acids pickings and their ultimate impact on consensus sequences present in mating type proteins using bioinformatics tools. Furthermore, we have also measured and walked through genomic DNA of various Sordaria strains to determine genetic diversity by genotyping the short sequence repeats (SSRs) of wild strains of S. fimicola collected from contrasting environments of two opposing slopes (harsh and xeric south facing slope and mild north facing slope) of Evolution Canyon (EC), Israel. Based on the whole genome sequence of S. macrospora, we targeted 20 genomic regions in S. fimicola which contain short sequence repeats (SSRs). Our data revealed genetic variations in strains from south facing slope and these findings assist in the hypothesis that genetic variations caused by stressful environments lead to evolution. PMID:28717646

Genetic Variation and Its Reflection on Posttranslational Modifications in Frequency Clock and Mating Type a-1 Proteins in Sordaria fimicola.

PubMed

Arif, Rabia; Akram, Faiza; Jamil, Tazeen; Mukhtar, Hamid; Lee, Siu Fai; Saleem, Muhammad

2017-01-01

Posttranslational modifications (PTMs) occur in all essential proteins taking command of their functions. There are many domains inside proteins where modifications take place on side-chains of amino acids through various enzymes to generate different species of proteins. In this manuscript we have, for the first time, predicted posttranslational modifications of frequency clock and mating type a-1 proteins in Sordaria fimicola collected from different sites to see the effect of environment on proteins or various amino acids pickings and their ultimate impact on consensus sequences present in mating type proteins using bioinformatics tools. Furthermore, we have also measured and walked through genomic DNA of various Sordaria strains to determine genetic diversity by genotyping the short sequence repeats (SSRs) of wild strains of S. fimicola collected from contrasting environments of two opposing slopes (harsh and xeric south facing slope and mild north facing slope) of Evolution Canyon (EC), Israel. Based on the whole genome sequence of S. macrospora , we targeted 20 genomic regions in S. fimicola which contain short sequence repeats (SSRs). Our data revealed genetic variations in strains from south facing slope and these findings assist in the hypothesis that genetic variations caused by stressful environments lead to evolution.

Penis size interacts with body shape and height to influence male attractiveness

PubMed Central

Mautz, Brian S.; Wong, Bob B. M.; Peters, Richard A.; Jennions, Michael D.

2013-01-01

Compelling evidence from many animal taxa indicates that male genitalia are often under postcopulatory sexual selection for characteristics that increase a male’s relative fertilization success. There could, however, also be direct precopulatory female mate choice based on male genital traits. Before clothing, the nonretractable human penis would have been conspicuous to potential mates. This observation has generated suggestions that human penis size partly evolved because of female choice. Here we show, based upon female assessment of digitally projected life-size, computer-generated images, that penis size interacts with body shape and height to determine male sexual attractiveness. Positive linear selection was detected for penis size, but the marginal increase in attractiveness eventually declined with greater penis size (i.e., quadratic selection). Penis size had a stronger effect on attractiveness in taller men than in shorter men. There was a similar increase in the positive effect of penis size on attractiveness with a more masculine body shape (i.e., greater shoulder-to-hip ratio). Surprisingly, larger penis size and greater height had almost equivalent positive effects on male attractiveness. Our results support the hypothesis that female mate choice could have driven the evolution of larger penises in humans. More broadly, our results show that precopulatory sexual selection can play a role in the evolution of genital traits. PMID:23569234

A Comparative Analysis of the Morphology and Evolution of Permanent Sperm Depletion in Spiders

PubMed Central

2011-01-01

Once thought to be energetically cheap and easy to produce, empirical work has shown that sperm is a costly and limited resource for males. In some spider species, there is behavioral evidence that sperm are permanently depleted after a single mating. This extreme degree of mating investment appears to co-occur with other reproductive strategies common to spiders, e.g. genital mutilation and sexual cannibalism. Here we corroborate that sperm depletion in the golden orb-web spider Nephila clavipes is permanent by uncovering its mechanistic basis using light and electron microscopy. In addition, we use a phylogeny-based statistical analysis to test the evolutionary relationships between permanent sperm depletion (PSD) and other reproductive strategies in spiders. Male testes do not produce sperm during adulthood, which is unusual in spiders. Instead, spermatogenesis is nearly synchronous and ends before the maturation molt. Testis size decreases as males approach their maturation molt and reaches its lowest point after sperm is transferred into the male copulatory organs (pedipalps). As a consequence, the amount of sperm available to males for mating is limited to the sperm contained in the pedipalps, and once it is used, males lose their ability to fertilize eggs. Our data suggest that PSD has evolved independently at least three times within web-building spiders and is significantly correlated with the evolution of other mating strategies that limit males to monogamy, including genital mutilation and sexual cannibalism. We conclude that PSD may be an energy-saving adaptation in species where males are limited to monogamy. This could be particularly important in web-building spiders where extreme sexual size dimorphism results in large, sedentary females and small, searching males who rarely feed as adults and are vulnerable to starvation. Future work will explore possible energetic benefits and the evolutionary lability of PSD relative to other mate-limiting reproductive behaviors. PMID:21264312

Genetic incompatibility drives mate choice in a parasitic wasp.

PubMed

Thiel, Andra; Weeda, Anne C; de Boer, Jetske G; Hoffmeister, Thomas S

2013-07-30

Allelic incompatibility between individuals of the same species should select for mate choice based on the genetic make-up of both partners at loci that influence offspring fitness. As a consequence, mate choice may be an important driver of allelic diversity. A complementary sex determination (CSD) system is responsible for intraspecific allelic incompatibility in many species of ants, bees, and wasps. CSD may thus favour disassortative mating and in this, resembles the MHC of the vertebrate immune system, or the self-incompatibility (SI) system of higher plants. Here we show that in the monogamous parasitic wasp Bracon brevicornis (Wesmael), females are able to reject partners with incompatible alleles. Forcing females to accept initially rejected partners resulted in sex ratio distortion and partial infertility of offspring. CSD-disassortative mating occurred independent of kin recognition and inbreeding avoidance in our experiment. The fitness consequences of mate choice are directly observable, not influenced by environmental effects, and more severe than in comparable systems (SI or MHC), on individuals as well as at the population level. Our results thus demonstrate the strong potential of female mate choice for maintaining high offspring fitness in this species.

Tissue remodeling: a mating-induced differentiation program for the Drosophila oviduct.

PubMed

Kapelnikov, Anat; Rivlin, Patricia K; Hoy, Ronald R; Heifetz, Yael

2008-12-08

In both vertebrates and invertebrates, the oviduct is an epithelial tube surrounded by visceral muscles that serves as a conduit for gamete transport between the ovary and uterus. While Drosophila is a model system for tubular organ development, few studies have addressed the development of the fly's oviduct. Recent studies in Drosophila have identified mating-responsive genes and proteins whose levels in the oviduct are altered by mating. Since many of these molecules (e.g. Muscle LIM protein 84B, Coracle, Neuroglian) have known roles in the differentiation of muscle and epithelia of other organs, mating may trigger similar differentiation events in the oviduct. This led us to hypothesize that mating mediates the last stages of oviduct differentiation in which organ-specific specializations arise. Using electron- and confocal-microscopy we identified tissue-wide post-mating changes in the oviduct including differentiation of cellular junctions, remodeling of extracellular matrix, increased myofibril formation, and increased innervation. Analysis of once- and twice-mated females reveals that some mating-responsive proteins respond only to the first mating, while others respond to both matings. We uncovered ultrastructural changes in the mated oviduct that are consistent with the roles that mating-responsive proteins play in muscle and epithelial differentiation elsewhere. This suggests that mating triggers the late differentiation of the oviduct. Furthermore, we suggest that mating-responsive proteins that respond only to the first mating are involved in the final maturation of the oviduct while proteins that remain responsive to later matings are also involved in maintenance and ongoing function of the oviduct. Taken together, our results establish the oviduct as an attractive system to address mechanisms that regulate the late stages of differentiation and maintenance of a tubular organ.

Tissue remodeling: a mating-induced differentiation program for the Drosophila oviduct

PubMed Central

Kapelnikov, Anat; Rivlin, Patricia K; Hoy, Ronald R; Heifetz, Yael

2008-01-01

Background In both vertebrates and invertebrates, the oviduct is an epithelial tube surrounded by visceral muscles that serves as a conduit for gamete transport between the ovary and uterus. While Drosophila is a model system for tubular organ development, few studies have addressed the development of the fly's oviduct. Recent studies in Drosophila have identified mating-responsive genes and proteins whose levels in the oviduct are altered by mating. Since many of these molecules (e.g. Muscle LIM protein 84B, Coracle, Neuroglian) have known roles in the differentiation of muscle and epithelia of other organs, mating may trigger similar differentiation events in the oviduct. This led us to hypothesize that mating mediates the last stages of oviduct differentiation in which organ-specific specializations arise. Results Using electron- and confocal-microscopy we identified tissue-wide post-mating changes in the oviduct including differentiation of cellular junctions, remodeling of extracellular matrix, increased myofibril formation, and increased innervation. Analysis of once- and twice-mated females reveals that some mating-responsive proteins respond only to the first mating, while others respond to both matings. Conclusion We uncovered ultrastructural changes in the mated oviduct that are consistent with the roles that mating-responsive proteins play in muscle and epithelial differentiation elsewhere. This suggests that mating triggers the late differentiation of the oviduct. Furthermore, we suggest that mating-responsive proteins that respond only to the first mating are involved in the final maturation of the oviduct while proteins that remain responsive to later matings are also involved in maintenance and ongoing function of the oviduct. Taken together, our results establish the oviduct as an attractive system to address mechanisms that regulate the late stages of differentiation and maintenance of a tubular organ. PMID:19063748

49 CFR 179.14 - Coupler vertical restraint system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... mating coupler (or simulated coupler) having only frictional vertical force resistance at the mating interface; or a mating coupler (or simulated coupler) having the capabilities described in paragraph (a) of this section; (2) The testing apparatus shall simulate the vertical coupler performance at the mating...

Rapid Evolution of Ovarian-Biased Genes in the Yellow Fever Mosquito (Aedes aegypti).

PubMed

Whittle, Carrie A; Extavour, Cassandra G

2017-08-01

Males and females exhibit highly dimorphic phenotypes, particularly in their gonads, which is believed to be driven largely by differential gene expression. Typically, the protein sequences of genes upregulated in males, or male-biased genes, evolve rapidly as compared to female-biased and unbiased genes. To date, the specific study of gonad-biased genes remains uncommon in metazoans. Here, we identified and studied a total of 2927, 2013, and 4449 coding sequences (CDS) with ovary-biased, testis-biased, and unbiased expression, respectively, in the yellow fever mosquito Aedes aegypti The results showed that ovary-biased and unbiased CDS had higher nonsynonymous to synonymous substitution rates (dN/dS) and lower optimal codon usage (those codons that promote efficient translation) than testis-biased genes. Further, we observed higher dN/dS in ovary-biased genes than in testis-biased genes, even for genes coexpressed in nonsexual (embryo) tissues. Ovary-specific genes evolved exceptionally fast, as compared to testis- or embryo-specific genes, and exhibited higher frequency of positive selection. Genes with ovary expression were preferentially involved in olfactory binding and reception. We hypothesize that at least two potential mechanisms could explain rapid evolution of ovary-biased genes in this mosquito: (1) the evolutionary rate of ovary-biased genes may be accelerated by sexual selection (including female-female competition or male-mate choice) affecting olfactory genes during female swarming by males, and/or by adaptive evolution of olfactory signaling within the female reproductive system ( e.g. , sperm-ovary signaling); and/or (2) testis-biased genes may exhibit decelerated evolutionary rates due to the formation of mating plugs in the female after copulation, which limits male-male sperm competition. Copyright © 2017 by the Genetics Society of America.

KSC-97PC1110

NASA Image and Video Library

1997-07-22

Flight mechanics from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., lower the Cassini spacecraft onto its launch vehicle adapter in KSC’s Payload Hazardous Servicing Facility. The adapter will later be mated to a Titan IV/Centaur expendable launch vehicle that will lift Cassini into space. Scheduled for launch in October, the Cassini mission, a joint US-European four-year orbital surveillance of Saturn's atmosphere and magnetosphere, its rings, and its moons, seeks insight into the origins and evolution of the early solar system. It will take seven years for the spacecraft to reach Saturn. JPL is managing the Cassini project for NASA

Multi-species mating disruption in cranberries (Ericales: Ericaceae): Early evidence using a flowable emulsion

USDA-ARS?s Scientific Manuscript database

Pheromone-based mating disruption has proven to be a powerful pest management tool in many cropping systems, helping to reduce reliance on insecticide applications. However, a sustainable mating disruption program has not yet been developed for cranberries. In the cranberry system, two of the major ...

49 CFR 179.14 - Coupler vertical restraint system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... system shall be tested under the following conditions: (1) The test coupler shall be tested with a mating coupler (or simulated coupler) having only frictional vertical force resistance at the mating interface; or a mating coupler (or simulated coupler) having the capabilities described in paragraph (a) of this...

The efficiency of close inbreeding to reduce genetic adaptation to captivity

PubMed Central

Theodorou, K; Couvet, D

2015-01-01

Although ex situ conservation is indispensable for thousands of species, captive breeding is associated with negative genetic changes: loss of genetic variance and genetic adaptation to captivity that is deleterious in the wild. We used quantitative genetic individual-based simulations to model the effect of genetic management on the evolution of a quantitative trait and the associated fitness of wild-born individuals that are brought to captivity. We also examined the feasibility of the breeding strategies under a scenario of a large number of loci subject to deleterious mutations. We compared two breeding strategies: repeated half-sib mating and a method of minimizing mean coancestry (referred to as gc/mc). Our major finding was that half-sib mating is more effective in reducing genetic adaptation to captivity than the gc/mc method. Moreover, half-sib mating retains larger allelic and adaptive genetic variance. Relative to initial standing variation, the additive variance of the quantitative trait increased under half-sib mating during the sojourn in captivity. Although fragmentation into smaller populations improves the efficiency of the gc/mc method, half-sib mating still performs better in the scenarios tested. Half-sib mating shows two caveats that could mitigate its beneficial effects: low heterozygosity and high risk of extinction when populations are of low fecundity and size and one of the following conditions are met: (i) the strength of selection in captivity is comparable with that in the wild, (ii) deleterious mutations are numerous and only slightly deleterious. Experimental validation of half-sib mating is therefore needed for the advancement of captive breeding programs. PMID:25052417

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.

The impact of self-incompatibility systems on the prevention of biparental inbreeding

PubMed Central

Furstenau, Tara N.

2017-01-01

Inbreeding in hermaphroditic plants can occur through two different mechanisms: biparental inbreeding, when a plant mates with a related individual, or self-fertilization, when a plant mates with itself. To avoid inbreeding, many hermaphroditic plants have evolved self-incompatibility (SI) systems which prevent or limit self-fertilization. One particular SI system—homomorphic SI—can also reduce biparental inbreeding. Homomorphic SI is found in many angiosperm species, and it is often assumed that the additional benefit of reduced biparental inbreeding may be a factor in the success of this SI system. To test this assumption, we developed a spatially-explicit, individual-based simulation of plant populations that displayed three different types of homomorphic SI. We measured the total level of inbreeding avoidance by comparing each population to a self-compatible population (NSI), and we measured biparental inbreeding avoidance by comparing to a population of self-incompatible plants that were free to mate with any other individual (PSI). Because biparental inbreeding is more common when offspring dispersal is limited, we examined the levels of biparental inbreeding over a range of dispersal distances. We also tested whether the introduction of inbreeding depression affected the level of biparental inbreeding avoidance. We found that there was a statistically significant decrease in autozygosity in each of the homomorphic SI populations compared to the PSI population and, as expected, this was more pronounced when seed and pollen dispersal was limited. However, levels of homozygosity and inbreeding depression were not reduced. At low dispersal, homomorphic SI populations also suffered reduced female fecundity and had smaller census population sizes. Overall, our simulations showed that the homomorphic SI systems had little impact on the amount of biparental inbreeding in the population especially when compared to the overall reduction in inbreeding compared to the NSI population. With further study, this observation may have important consequences for research into the origin and evolution of homomorphic self-incompatibility systems. PMID:29188143

An Overview of the Function and Maintenance of Sexual Reproduction in Dikaryotic Fungi

PubMed Central

Wallen, R. M.; Perlin, Michael H.

2018-01-01

Sexual reproduction likely evolved as protection from environmental stresses, specifically, to repair DNA damage, often via homologous recombination. In higher eukaryotes, meiosis and the production of gametes with allelic combinations different from parental type provides the side effect of increased genetic variation. In fungi it appears that while the maintenance of meiosis is paramount for success, outcrossing is not a driving force. In the subkingdom Dikarya, fungal members are characterized by existence of a dikaryon for extended stages within the life cycle. Such fungi possess functional or, in some cases, relictual, loci that govern sexual reproduction between members of their own species. All mating systems identified so far in the Dikarya employ a pheromone/receptor system for haploid organisms to recognize a compatible mating partner, although the paradigm in the Ascomycota, e.g., Saccharomyces cerevisiae, is that genes for the pheromone precursor and receptor are not found in the mating-type locus but rather are regulated by its products. Similarly, the mating systems in the Ascomycota are bipolar, with two non-allelic idiomorphs expressed in cells of opposite mating type. In contrast, for the Basidiomycota, both bipolar and tetrapolar mating systems have been well characterized; further, at least one locus directly encodes the pheromone precursor and the receptor for the pheromone of a different mating type, while a separate locus encodes proteins that may regulate the first locus and/or additional genes required for downstream events. Heterozygosity at both of two unlinked loci is required for cells to productively mate in tetrapolar systems, whereas in bipolar systems the two loci are tightly linked. Finally, a trade-off exists in wild fungal populations between sexual reproduction and the associated costs, with adverse conditions leading to mating. For fungal mammal pathogens, the products of sexual reproduction can be targets for the host immune system. The opposite appears true for phytopathogenic fungi, where mating and pathogenicity are inextricably linked. Here, we explore, compare, and contrast different strategies used among the Dikarya, both saprophytic and pathogenic fungi, and highlight differences between pathogens of mammals and pathogens of plants, providing context for selective pressures acting on this interesting group of fungi. PMID:29619017

Gradient Evolution of Body Colouration in Surface- and Cave-Dwelling Poecilia mexicana and the Role of Phenotype-Assortative Female Mate Choice

PubMed Central

Penshorn, Marina; Hamfler, Sybille; Herbert, Denise B.; Appel, Jessica; Meyer, Philipp; Slattery, Patrick; Charaf, Sarah; Wolf, Raoul; Völker, Johannes; Berger, Elisabeth A. M.; Dröge, Janis; Riesch, Rüdiger; Arias-Rodriguez, Lenin; Indy, Jeanne R.; Plath, Martin

2013-01-01

Ecological speciation assumes reproductive isolation to be the product of ecologically based divergent selection. Beside natural selection, sexual selection via phenotype-assortative mating is thought to promote reproductive isolation. Using the neotropical fish Poecilia mexicana from a system that has been described to undergo incipient ecological speciation in adjacent, but ecologically divergent habitats characterized by the presence or absence of toxic H2S and darkness in cave habitats, we demonstrate a gradual change in male body colouration along the gradient of light/darkness, including a reduction of ornaments that are under both inter- and intrasexual selection in surface populations. In dichotomous choice tests using video-animated stimuli, we found surface females to prefer males from their own population over the cave phenotype. However, female cave fish, observed on site via infrared techniques, preferred to associate with surface males rather than size-matched cave males, likely reflecting the female preference for better-nourished (in this case: surface) males. Hence, divergent selection on body colouration indeed translates into phenotype-assortative mating in the surface ecotype, by selecting against potential migrant males. Female cave fish, by contrast, do not have a preference for the resident male phenotype, identifying natural selection against migrants imposed by the cave environment as the major driver of the observed reproductive isolation. PMID:24175282

Global population structure and adaptive evolution of aflatoxin-producing fungi

USDA-ARS?s Scientific Manuscript database

We employed interspecific principal component analyses for six different categories (geography, species, precipitation, temperature, aflatoxin chemotype profile, and mating type) and inferred maximum likelihood phylogenies for six combined loci, including two aflatoxin cluster regions (aflM/alfN and...

Is there a role for amplifiers in sexual selection?

PubMed

Gualla, Filippo; Cermelli, Paolo; Castellano, Sergio

2008-05-21

The amplifier hypothesis states that selection could favour the evolution of traits in signallers that improve the ability of receivers to extract honest information from other signals or cues. We provide a formal definition of amplifiers based on the receiver's mechanisms of signal perception and we present a game-theoretical model in which males advertise their quality and females use sequential-sampling tactics to choose among prospective mates. The main effect of an amplifier on the female mating strategy is to increase her mating threshold, making the female more selective as the effectiveness of the amplifier increases. The effects of the amplifier on male advertising strategy depends both on the context and on the types of the amplifier involved. We consider two different contexts for the evolution of amplifiers (when the effect of amplifiers is on signals and when it is on cues) and two types of amplifiers (the 'neutral amplifier', when it improves quality assessment without altering male attractiveness, and the 'attractive amplifier', when it improves both quality assessment and male attractiveness). The game-theoretical model provides two main results. First, neutral and attractive amplifiers represent, respectively, a conditional and an unconditional signalling strategy. In fact, at the equilibrium, neutral amplifiers are displayed only by males whose advertising level lays above the female acceptance threshold, whereas attractive amplifiers are displayed by all signalling males, independent of their quality. Second, amplifiers of signals increase the differences in advertising levels between amplifying and not-amplifying males, but they decrease the differences within each group, so that the system converges towards an 'all-or-nothing' signalling strategy. By applying concepts from information theory, we show that the increase in information transfer at the perception level due to the amplifier of signals is contrasted by a decrease in information transfer at the emitter level due to the increased stereotypy of male advertising strategy.

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.

Aposematism increases acoustic diversification and speciation in poison frogs

PubMed Central

Santos, Juan C.; Baquero, Margarita; Barrio-Amorós, César; Coloma, Luis A.; Erdtmann, Luciana K.; Lima, Albertina P.; Cannatella, David C.

2014-01-01

Multimodal signals facilitate communication with conspecifics during courtship, but they can also alert eavesdropper predators. Hence, signallers face two pressures: enticing partners to mate and avoiding detection by enemies. Undefended organisms with limited escape abilities are expected to minimize predator recognition over mate attraction by limiting or modifying their signalling. Alternatively, organisms with anti-predator mechanisms such as aposematism (i.e. unprofitability signalled by warning cues) might elaborate mating signals as a consequence of reduced predation. We hypothesize that calls diversified in association with aposematism. To test this, we assembled a large acoustic signal database for a diurnal lineage of aposematic and cryptic/non-defended taxa, the poison frogs. First, we showed that aposematic and non-aposematic species share similar extinction rates, and aposematic lineages diversify more and rarely revert to the non-aposematic phenotype. We then characterized mating calls based on morphological (spectral), behavioural/physiological (temporal) and environmental traits. Of these, only spectral and temporal features were associated with aposematism. We propose that with the evolution of anti-predator defences, reduced predation facilitated the diversification of vocal signals, which then became elaborated or showy via sexual selection. PMID:25320164

Male-induced costs of mating for females compensated by offspring viability benefits in an insect.

PubMed

Garcia-Gonzalez, F; Simmons, L W

2010-10-01

Sexual conflict facilitates the evolution of traits that increase the reproductive success of males at the expense of components of female fitness. Theory suggests that indirect benefits are unlikely to offset the direct costs to females from antagonistic male adaptations, but empirical studies examining the net fitness pay-offs of the interaction between the sexes are scarce. Here, we investigate whether matings with males that invest intrinsically more into accessory gland tissue undermine female lifetime reproductive success (LRS) in the cricket Teleogryllus oceanicus. We found that females incur a longevity cost of mating that is proportional to the partner's absolute investment into the production of accessory gland products. However, male accessory gland weight positively influences embryo survival, and harmful ejaculate-induced effects are cancelled out when these are put in the context of female LRS. The direct costs of mating with males that sire offspring with higher viability are thus compensated by direct and possibly indirect genetic benefits in this species. © 2010 The Authors. Journal Compilation © 2010 European Society For Evolutionary Biology.

An experimental test for indirect benefits in Drosophila melanogaster

PubMed Central

Rundle, Howard D; Ödeen, Anders; Mooers, Arne Ø

2007-01-01

Background Despite much empirical attention, tests for indirect benefits of mate choice have rarely considered the major components of sexual and nonsexual offspring fitness relevant to a population. Here we use a novel experimental design to test for the existence of any indirect benefits in a laboratory adapted population of D. melanogaster. Our experiment compared the fitness (mating success, longevity, and productivity) of individuals possessing genomes that derived two generations previously from males that were either entirely successful (studs) or wholly unsuccessful (duds) at achieving mates in three subsequent rounds of mating trials. Results Males from the stud treatment were 30% more successful on average at securing mates than males from the dud treatment. In contrast, we found no difference between treatments in measures of productivity or of longevity when measured in a mixed-sex environment. In the absence of females, however, males in the stud treatment outlived males in the dud treatment. Conclusion Our results suggest that mating with successful males in this population provides an indirect benefit to females and that, at least in this environment, the benefit arises primarily through the production of more attractive male offspring. However, it is unclear whether this represents solely a traditional sexy sons benefit or whether there is an additional good genes component (with male offspring simply allocating their surplus condition to traits that enhance their mating success). The lack of any detectable differences in female fitness between the two treatments suggests the former, although the longevity advantage of males in the stud treatment when females were absent is consistent with the latter. Determining the effect of this indirect benefit on the evolution of female mate preferences (or resistance) will require comparable data on the direct costs of mating with various males, and an understanding of how these costs and benefits integrate across generations and vary among environments. PMID:17349042

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.

The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity

PubMed Central

Kimura, Kazuki; Chiba, Satoshi

2015-01-01

Several taxa of simultaneously hermaphroditic land snails exhibit a conspicuous mating behaviour, the so-called shooting of love darts. During mating, such land snail species transfer a specific secretion by stabbing a mating partner's body with the love dart. It has been shown that sperm donors benefit from this traumatic secretion transfer, because the secretions manipulate the physiology of a sperm recipient and increase the donors' fertilization success. However, it is unclear whether reception of dart shooting is costly to the recipients. Therefore, the effect of sexual conflict and antagonistic arms races on the evolution of traumatic secretion transfer in land snails is still controversial. To examine this effect, we compared lifetime fecundity and longevity between the individuals that received and did not receive dart shooting from mating partners in Bradybaena pellucida. Our experiments showed that the dart-receiving snails suffered reduction in lifetime fecundity and longevity. These results suggest that the costly mating behaviour, dart shooting, generates conflict between sperm donors and recipients and that sexually antagonistic arms races have contributed to the diversification of the morphological and behavioural traits relevant to dart shooting. Our findings also support theories suggesting a violent escalation of sexual conflict in hermaphroditic animals. PMID:25761713

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

Evidence for mate guarding behavior in the Taylor's checkerspot butterfly

Treesearch

Victoria J. Bennett; Winston P. Smith; Matthew G. Betts

2011-01-01

Discerning the intricacies of mating systems in butterflies can be difficult, particularly when multiple mating strategies are employed and are cryptic and not exclusive. We observed the behavior and habitat use of 113 male Taylor's checkerspot butterflies (Euphydryas editha taylori). We confirmed that two distinct mating strategies were...

Host social organization and mating system shape parasite transmission opportunities in three European bat species.

PubMed

van Schaik, J; Kerth, G

2017-02-01

For non-mobile parasites living on social hosts, infection dynamics are strongly influenced by host life history and social system. We explore the impact of host social systems on parasite population dynamics by comparing the infection intensity and transmission opportunities of three mite species of the genus Spinturnix across their three European bat hosts (Myotis daubentonii, Myotis myotis, Myotis nattereri) during the bats' autumn mating season. Mites mainly reproduce in host maternity colonies in summer, but as these colonies are closed, opportunities for inter-colony transmission are limited to host interactions during the autumn mating season. The three investigated hosts differ considerably in their social system, most notably in maternity colony size, mating system, and degree of male summer aggregation. We observed marked differences in parasite infection during the autumn mating period between the species, closely mirroring the predictions made based on the social systems of the hosts. Increased host aggregation sizes in summer yielded higher overall parasite prevalence and intensity, both in male and female hosts. Moreover, parasite levels in male hosts differentially increased throughout the autumn mating season in concordance with the degree of contact with female hosts afforded by the different mating systems of the hosts. Critically, the observed host-specific differences have important consequences for parasite population structure and will thus affect the coevolutionary dynamics between the interacting species. Therefore, in order to accurately characterize host-parasite dynamics in hosts with complex social systems, a holistic approach that investigates parasite infection and transmission across all periods is warranted.

Sexual selection expedites the evolution of pesticide resistance.

PubMed

Jacomb, Frances; Marsh, Jason; Holman, Luke

2016-12-01

The evolution of insecticide resistance by crop pests and disease vectors causes serious problems for agriculture and health. Sexual selection can accelerate or hinder adaptation to abiotic challenges in a variety of ways, but the effect of sexual selection on resistance evolution is little studied. Here, we examine this question using experimental evolution in the pest insect Tribolium castaneum. The experimental removal of sexual selection slowed the evolution of resistance in populations treated with pyrethroid pesticide, and also reduced the rate at which resistance was lost from pesticide-free populations. These results suggest that selection arising from variance in mating and fertilization success can augment natural selection on pesticide resistance, meaning that sexual selection should be considered when designing strategies to limit the evolution of pesticide resistance. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Females use self-referent cues to avoid mating with previous mates.

PubMed

Ivy, Tracie M; Weddle, Carie B; Sakaluk, Scott K

2005-12-07

Females of many species mate repeatedly throughout their lives, often with many different males (polyandry). Females can secure genetic benefits by maximizing their diversity of mating partners, and might be expected, therefore, to forego matings with previous partners in favour of novel males. Indeed, a female preference for novel mating partners has been shown in several taxa, but the mechanism by which females distinguish between novel males and previous mates remains unknown. We show that female crickets (Gryllodes sigillatus) mark males with their own unique chemical signatures during mating, enabling females to recognize prior mates in subsequent encounters and to avoid remating with them. Because self-referent chemosensory cues provide females with a simple, but reliable mechanism of identifying individuals with whom they have mated without requiring any special cognitive ability, they may be a widespread means by which females across a broad range of animal mating systems maximize the genetic benefits of polyandry.

Females use self-referent cues to avoid mating with previous mates

PubMed Central

Ivy, Tracie M; Weddle, Carie B; Sakaluk, Scott K

2005-01-01

Females of many species mate repeatedly throughout their lives, often with many different males (polyandry). Females can secure genetic benefits by maximizing their diversity of mating partners, and might be expected, therefore, to forego matings with previous partners in favour of novel males. Indeed, a female preference for novel mating partners has been shown in several taxa, but the mechanism by which females distinguish between novel males and previous mates remains unknown. We show that female crickets (Gryllodes sigillatus) mark males with their own unique chemical signatures during mating, enabling females to recognize prior mates in subsequent encounters and to avoid remating with them. Because self-referent chemosensory cues provide females with a simple, but reliable mechanism of identifying individuals with whom they have mated without requiring any special cognitive ability, they may be a widespread means by which females across a broad range of animal mating systems maximize the genetic benefits of polyandry. PMID:16271971

Deciphering evolutionary strata on plant sex chromosomes and fungal mating-type chromosomes through compositional segmentation.

PubMed

Pandey, Ravi S; Azad, Rajeev K

2016-03-01

Sex chromosomes have evolved from a pair of homologous autosomes which differentiated into sex determination systems, such as XY or ZW system, as a consequence of successive recombination suppression between the gametologous chromosomes. Identifying the regions of recombination suppression, namely, the "evolutionary strata", is central to understanding the history and dynamics of sex chromosome evolution. Evolution of sex chromosomes as a consequence of serial recombination suppressions is well-studied for mammals and birds, but not for plants, although 48 dioecious plants have already been reported. Only two plants Silene latifolia and papaya have been studied until now for the presence of evolutionary strata on their X chromosomes, made possible by the sequencing of sex-linked genes on both the X and Y chromosomes, which is a requirement of all current methods that determine stratum structure based on the comparison of gametologous sex chromosomes. To circumvent this limitation and detect strata even if only the sequence of sex chromosome in the homogametic sex (i.e. X or Z chromosome) is available, we have developed an integrated segmentation and clustering method. In application to gene sequences on the papaya X chromosome and protein-coding sequences on the S. latifolia X chromosome, our method could decipher all known evolutionary strata, as reported by previous studies. Our method, after validating on known strata on the papaya and S. latifolia X chromosome, was applied to the chromosome 19 of Populus trichocarpa, an incipient sex chromosome, deciphering two, yet unknown, evolutionary strata. In addition, we applied this approach to the recently sequenced sex chromosome V of the brown alga Ectocarpus sp. that has a haploid sex determination system (UV system) recovering the sex determining and pseudoautosomal regions, and then to the mating-type chromosomes of an anther-smut fungus Microbotryum lychnidis-dioicae predicting five strata in the non-recombining region of both the chromosomes.

The Landscape of A-to-I RNA Editome Is Shaped by Both Positive and Purifying Selection

PubMed Central

Kong, Yimeng; Pan, Bohu; Chen, Longxian; Wang, Hongbing; Hao, Pei; Li, Xuan

2016-01-01

The hydrolytic deamination of adenosine to inosine (A-to-I editing) in precursor mRNA induces variable gene products at the post-transcription level. How and to what extent A-to-I RNA editing diversifies transcriptome is not fully characterized in the evolution, and very little is known about the selective constraints that drive the evolution of RNA editing events. Here we present a study on A-to-I RNA editing, by generating a global profile of A-to-I editing for a phylogeny of seven Drosophila species, a model system spanning an evolutionary timeframe of approximately 45 million years. Of totally 9281 editing events identified, 5150 (55.5%) are located in the coding sequences (CDS) of 2734 genes. Phylogenetic analysis places these genes into 1,526 homologous families, about 5% of total gene families in the fly lineages. Based on conservation of the editing sites, the editing events in CDS are categorized into three distinct types, representing events on singleton genes (type I), and events not conserved (type II) or conserved (type III) within multi-gene families. While both type I and II events are subject to purifying selection, notably type III events are positively selected, and highly enriched in the components and functions of the nervous system. The tissue profiles are documented for three editing types, and their critical roles are further implicated by their shifting patterns during holometabolous development and in post-mating response. In conclusion, three A-to-I RNA editing types are found to have distinct evolutionary dynamics. It appears that nervous system functions are mainly tested to determine if an A-to-I editing is beneficial for an organism. The coding plasticity enabled by A-to-I editing creates a new class of binary variations, which is a superior alternative to maintain heterozygosity of expressed genes in a diploid mating system. PMID:27467689

Ecological constraints on breeding system evolution: the influence of habitat on brood desertion in Kentish plover.

PubMed

Kosztolányi, András; Székely, Tamas; Cuthill, Innes C; Yilmaz, K Tuluhan; Berberoglu, Süha

2006-01-01

1. One of the fundamental insights of behavioural ecology is that resources influence breeding systems. For instance, when food resources are plenty, one parent is able to care for the young on its own, so that the other parent can desert and became polygamous. We investigated this hypothesis in the context of classical polyandry when females may have several mates within a single breeding season, and parental duties are carried out largely by the male. 2. We studied a precocial wader, the Kentish plover Charadrius alexandrinus, that exhibits variable brood care such that the chicks may be raised by both parents, only by the female or, more often, only by the male. The timing of female desertion varies: some females desert their brood at hatching of the eggs and lay a clutch for a new mate, whereas other females stay with their brood until the chicks fledge. Kentish plovers are excellent organisms with which to study breeding system evolution, as some of their close relatives exhibit classical polyandry (Eurasian dotterel Eudromias morinellus, mountain plover Charadrius montanus), whereas others are polygynous (northern lapwing Vanellus vanellus). 3. Kentish plovers raised their broods in two habitats in our study site in southern Turkey: saltmarsh and lakeshore. Food intake was higher on the lakeshore than in the saltmarsh as judged from feeding behaviour of chicks and adults. As the season proceeded and the saltmarsh dried out, the broods moved toward the lakeshore. 4. As the density of plovers increased on lakeshore, the parents spent more time defending their young, and female parents stayed with their brood longer on the lakeshore. 5. We conclude that the influence of food abundance on breeding systems is more complex than currently anticipated. Abundant food resources appear to have profound implications on spatial distribution of broods, and the social interactions between broods constrain female desertion and polyandry.

Multimodal sensorimotor system in unicellular zoospores of a fungus.

PubMed

Swafford, Andrew J M; Oakley, Todd H

2018-01-19

Complex sensory systems often underlie critical behaviors, including avoiding predators and locating prey, mates and shelter. Multisensory systems that control motor behavior even appear in unicellular eukaryotes, such as Chlamydomonas , which are important laboratory models for sensory biology. However, we know of no unicellular opisthokonts that control motor behavior using a multimodal sensory system. Therefore, existing single-celled models for multimodal sensorimotor integration are very distantly related to animals. Here, we describe a multisensory system that controls the motor function of unicellular fungal zoospores. We found that zoospores of Allomyces arbusculus exhibit both phototaxis and chemotaxis. Furthermore, we report that closely related Allomyces species respond to either the chemical or the light stimuli presented in this study, not both, and likely do not share this multisensory system. This diversity of sensory systems within Allomyces provides a rare example of a comparative framework that can be used to examine the evolution of sensory systems following the gain/loss of available sensory modalities. The tractability of Allomyces and related fungi as laboratory organisms will facilitate detailed mechanistic investigations into the genetic underpinnings of novel photosensory systems, and how multisensory systems may have functioned in early opisthokonts before multicellularity allowed for the evolution of specialized cell types. © 2018. Published by The Company of Biologists Ltd.

Sexual orientation in males and the evolution of anisogamy.

PubMed

Reed, Lawrence Ian

2010-02-01

How might homosexual orientation have evolved and been maintained? Several adaptationist explanations have been examined in attempt to reconcile the presence of same-sex sexual behaviors with traditional selection-based theory, showing little empirical support. The current paper presents a novel adaptationist explanation for the evolution and maintenance of same-sex sexual behaviors in males, both between- and within-species, related to the evolution of anisogamy. Under conditions of isogamy, sexual reproduction occurs between individuals with gametes of similar morphology. With the evolution of anisogamy came greater specificity on the types of individuals that would produce offspring when mated with (i.e. those with opposing gamete sizes). It is suggested that with this evolutionary change, a specified psychological adaptation orienting individuals primarily towards mating partners with newly opposing gamete sizes was then selected for. It is thus hypothesized that sexual orientation will vary along the anisogamy-isogamy continuum, with homosexual orientation being associated with closer approximations towards isogamy. This hypothesis leads to two specific predictions. First, in comparisons between species, the presence of same-sex sexual behaviors will be more likely to occur as sperm to egg ratios approach 1:1. Second, in comparisons within species, those individuals with greater sperm lengths will be more likely to exhibit same-sex sexual behaviors than those with lesser sperm lengths. Examination of the present hypothesis stands to greatly increase our knowledge of the selective forces shaping both biological and psychological evolution.

The correlated evolution of three-dimensional reproductive structures between male and female damselflies.

PubMed

McPeek, Mark A; Shen, Li; Farid, Hany

2009-01-01

For many taxa, species are defined by the morphologies of reproductive structures. In many odonates, these structures are the cerci of males (used to hold females during mating) and the thoracic plates of females where the male cerci contact the females' bodies. A previous study showed that the shapes of cerci of Enallagma males (Zygoptera: Coenagrionidae) are best explained by an evolutionary model of punctuated change at the time of speciation, with a homogeneous rate of change across the entire phylogeny of the genus. In the present study, we examine the evolution of shape change in the corresponding female plates. We found that, like male cerci, the shapes of Enallagma female thoracic plates could best be explained by an evolutionary model of punctuated change at the time of speciation, with a homogeneous rate of change across the clade. Moreover, the evolutionary contrasts quantifying the rates of change in male cerci and female thoracic plates were positively related across the history of the clade, demonstrating that these male and female structures evolve in a correlated fashion. This pattern of evolution suggests that these structures are primary signals of species identity during mating.

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

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.

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.

Evolution of pathogenicity and sexual reproduction in eight Candida genomes

PubMed Central

Butler, Geraldine; Rasmussen, Matthew D.; Lin, Michael F.; Santos, Manuel A.S.; Sakthikumar, Sharadha; Munro, Carol A.; Rheinbay, Esther; Grabherr, Manfred; Forche, Anja; Reedy, Jennifer L.; Agrafioti, Ino; Arnaud, Martha B.; Bates, Steven; Brown, Alistair J.P.; Brunke, Sascha; Costanzo, Maria C.; Fitzpatrick, David A.; de Groot, Piet W. J.; Harris, David; Hoyer, Lois L.; Hube, Bernhard; Klis, Frans M.; Kodira, Chinnappa; Lennard, Nicola; Logue, Mary E.; Martin, Ronny; Neiman, Aaron M.; Nikolaou, Elissavet; Quail, Michael A.; Quinn, Janet; Santos, Maria C.; Schmitzberger, Florian F.; Sherlock, Gavin; Shah, Prachi; Silverstein, Kevin; Skrzypek, Marek S.; Soll, David; Staggs, Rodney; Stansfield, Ian; Stumpf, Michael P H; Sudbery, Peter E.; Thyagarajan, Srikantha; Zeng, Qiandong; Berman, Judith; Berriman, Matthew; Heitman, Joseph; Gow, Neil A. R.; Lorenz, Michael C.; Birren, Bruce W.; Kellis, Manolis; Cuomo, Christina A.

2009-01-01

Candida species are the most common cause of opportunistic fungal infection worldwide. We report the genome sequences of six Candida species and compare these and related pathogens and nonpathogens. There are significant expansions of cell wall, secreted, and transporter gene families in pathogenic species, suggesting adaptations associated with virulence. Large genomic tracts are homozygous in three diploid species, possibly resulting from recent recombination events. Surprisingly, key components of the mating and meiosis pathways are missing from several species. These include major differences at the Mating-type loci (MTL); Lodderomyces elongisporus lacks MTL, and components of the a1/alpha2 cell identity determinant were lost in other species, raising questions about how mating and cell types are controlled. Analysis of the CUG leucine to serine genetic code change reveals that 99% of ancestral CUG codons were erased and new ones arose elsewhere. Lastly, we revise the C. albicans gene catalog, identifying many new genes. PMID:19465905

Female preferences drive the evolution of mimetic accuracy in male sexual displays.

PubMed

Coleman, Seth William; Patricelli, Gail Lisa; Coyle, Brian; Siani, Jennifer; Borgia, Gerald

2007-10-22

Males in many bird species mimic the vocalizations of other species during sexual displays, but the evolutionary and functional significance of interspecific vocal mimicry is unclear. Here we use spectrographic cross-correlation to compare mimetic calls produced by male satin bowerbirds (Ptilonorhynchus violaceus) in courtship with calls from several model species. We show that the accuracy of vocal mimicry and the number of model species mimicked are both independently related to male mating success. Multivariate analyses revealed that these mimetic traits were better predictors of male mating success than other male display traits previously shown to be important for male mating success. We suggest that preference-driven mimetic accuracy may be a widespread occurrence, and that mimetic accuracy may provide females with important information about male quality. Our findings support an alternative hypothesis to help explain a common element of male sexual displays.

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

Workers in the VPF observe the lower end of the IUS to be mated to the Chandra X-ray Observatory

NASA Technical Reports Server (NTRS)

1999-01-01

Workers in the Vertical Processing Facility observe the lower end of the Inertial Upper Stage (IUS) that will be mated with the Chandra X-ray Observatory (out of sight above it). After the two components are mated, they will undergo testing to validate the IUS/Chandra connections and to check the orbiter avionics interfaces. Following that, an end-to-end test (ETE) will be conducted to verify the communications path to Chandra, commanding it as if it were in space. With the world's most powerful X-ray telescope, Chandra will allow scientists from around the world to see previously invisible black holes and high-temperature gas clouds, giving the observatory the potential to rewrite the books on the structure and evolution of our universe. Chandra is scheduled for launch July 22 aboard Space Shuttle Columbia, on mission STS-93.

Sex-Linked Mating Strategies Diverge with a Manipulation of Genital Salience.

PubMed

Fetterman, Adam K; Kruger, Nicole N; Robinson, Michael D

2015-02-01

Trivers (1972) proposed that evolutionary factors should favor divergent mating strategies for males versus females. Such differences may be less pronounced among human beings than other animals and social norms and sex roles are also pertinent influences. The present experiment ( N = 133 college undergraduates, 74 female) sought to bypass some of these other influences. Participants were randomly assigned to a condition designed to increase attention to the genital region (a downward pointing arrow) or not (an upward pointing arrow). They then reported on their interest in short-term (e.g., a one-night stand) and long-term (e.g., a potential marital partner) mating opportunities. A theory-consistent three-way interaction occurred such that the genital salience manipulation primed a shorter-term reproductive strategy among men and a longer-term reproductive strategy among women. The results provide unique support for evolution-linked ideas about sex differences in the form of a role for bodily attention.

Advanced Mating System Development for Space Applications

NASA Technical Reports Server (NTRS)

Lewis, James L.

2004-01-01

This slide presentation reviews the development of space flight sealing and the work required for the further development of a dynamic interface seal for the use on space mating systems to support a fully androgynous mating interface. This effort has resulted in the advocacy of developing a standard multipurpose interface for use with all modern modular space architecture. This fully androgynous design means a seal-on-seal (SOS) system.

Investigating a novel pathway by which pheromone-based mating disruption may protect crops

USDA-ARS?s Scientific Manuscript database

Pheromone-based mating disruption has been a successful, relatively new technology that growers use to reduce key insect populations. Mating disruption systems function by sending out false plumes of the insect sex pheromones – this interferes with the insect’s ability to find a mate, preempting egg...

The role of inbreeding and outbreeding in herbivore resistance and tolerance in Vincetoxicum hirundinaria

PubMed Central

Muola, Anne; Mutikainen, Pia; Laukkanen, Liisa; Lilley, Marianna; Leimu, Roosa

2011-01-01

Background and Aims Inbreeding via self-fertilization may have negative effects on plant fitness (i.e. inbreeding depression). Outbreeding, or cross-fertilization between genetically dissimilar parental plants, may also disrupt local adaptation or allelic co-adaptation in the offspring and again lead to reduced plant fitness (i.e. outbreeding depression). Inbreeding and outbreeding may also increase plant vulnerability to natural enemies by altering plant quality or defence. The effects of inbreeding and outbreeding on plant size and response to herbivory in the perennial herb, Vincetoxicum hirundinaria, were investigated. Methods Greenhouse experiments were conducted using inbred and outbred (within- and between-population) offspring of 20 maternal plants from four different populations, quantifying plant germination, size, resistance against the specialist folivore, Abrostola asclepiadis, and tolerance of simulated defoliation. Key Results Selfed plants were smaller and more susceptible to damage by A. asclepiadis than outcrossed plants. However, herbivore biomass on selfed and outcrossed plants did not differ. The effects of inbreeding on plant performance and resistance did not differ among plant populations or families, and no inbreeding depression at all was found in tolerance of defoliation. Between-population outcrossing had no effect on plant performance or resistance against A. asclepiadis, indicating a lack of outbreeding depression. Conclusions Since inbreeding depression negatively affects plant size and herbivore resistance, inbreeding may modify the evolution of the interaction between V. hirundinaria and its specialist folivore. The results further suggest that herbivory may contribute to the maintenance of a mixed mating system of the host plants by selecting for outcrossing and reduced susceptibility to herbivore attack, and thus add to the growing body of evidence on the effects of inbreeding on the mating system evolution of the host plants and the dynamics of plant–herbivore interactions. PMID:21803741

Do gray wolves (Canis lupus) support pack mates during aggressive inter-pack interactions?

PubMed

Cassidy, Kira A; McIntyre, Richard T

2016-09-01

For group-living mammals, social coordination increases success in everything from hunting and foraging (Crofoot and Wrangham in Mind the Gap, Springer, Berlin, 2010; Bailey et al. in Behav Ecol Sociobiol 67:1-17, 2013) to agonism (Mosser and Packer in Anim Behav 78:359-370, 2009; Wilson et al. in Anim Behav 83:277-291, 2012; Cassidy et al. in Behav Ecol 26:1352-1360, 2015). Cooperation is found in many species and, due to its low costs, likely is a determining factor in the evolution of living in social groups (Smith in Anim Behav 92:291-304, 2014). Beyond cooperation, many mammals perform costly behaviors for the benefit of group mates (e.g., parental care, food sharing, grooming). Altruism is considered the most extreme case of cooperation where the altruist increases the fitness of the recipient while decreasing its own fitness (Bell in Selection: the mechanism of evolution. Oxford University Press, Oxford 2008). Gray wolf life history requires intra-pack familiarity, communication, and cooperation in order to succeed in hunting (MacNulty et al. in Behav Ecol doi: 10.1093/beheco/arr159 2011) and protecting group resources (Stahler et al. in J Anim Ecol 82: 222-234, 2013; Cassidy et al. in Behav Ecol 26:1352-1360, 2015). Here, we report 121 territorial aggressive inter-pack interactions in Yellowstone National Park between 1 April 1995 and 1 April 2011 (>5300 days of observation) and examine each interaction where one wolf interferes when its pack mate is being attacked by a rival group. This behavior was recorded six times (17.6 % of interactions involving an attack) and often occurred between dyads of closely related individuals. We discuss this behavior as it relates to the evolution of cooperation, sociality, and altruism.

Design and research on the two-joint mating system of underwater vehicle

NASA Astrophysics Data System (ADS)

Zhang, Zhong-lin; Wang, Li-quan

2013-03-01

In the 21st century, people have come to the era of ocean science and ocean economy. With the development of ocean science and technology and the thorough research on the ocean, underwater mating technique has been widely used in such fields as sunk ship salvage, deep ocean workstation, submarine lifesaving aid and military affairs. In this paper, researches are made home and abroad on mating technology. Two-joint mating system of underwater vehicle is designed including plane system, three-dimensional assembly system and control system in order to increase the capacity of adapting platform obliquity and adopting rotational skirt scheme. It is clear that the system fits the working space of underwater vehicle passageway and there is no interference phenomenon in assembly design. The finite element model of the system shell and the pressurization of the joint are established. The results of the finite element computing and the pressing test are accordant, and thus it can testify that the shell material meet the need of intension and joint pressurization is reliable. Modeling of the control system is accomplished, and simulation and analysis are made, which can provide directions for the controller design of mating system of underwater vehicles.

Thermal Equilibrium of a Macroscopic Quantum System in a Pure State.

PubMed

Goldstein, Sheldon; Huse, David A; Lebowitz, Joel L; Tumulka, Roderich

2015-09-04

We consider the notion of thermal equilibrium for an individual closed macroscopic quantum system in a pure state, i.e., described by a wave function. The macroscopic properties in thermal equilibrium of such a system, determined by its wave function, must be the same as those obtained from thermodynamics, e.g., spatial uniformity of temperature and chemical potential. When this is true we say that the system is in macroscopic thermal equilibrium (MATE). Such a system may, however, not be in microscopic thermal equilibrium (MITE). The latter requires that the reduced density matrices of small subsystems be close to those obtained from the microcanonical, equivalently the canonical, ensemble for the whole system. The distinction between MITE and MATE is particularly relevant for systems with many-body localization for which the energy eigenfuctions fail to be in MITE while necessarily most of them, but not all, are in MATE. We note, however, that for generic macroscopic systems, including those with MBL, most wave functions in an energy shell are in both MATE and MITE. For a classical macroscopic system, MATE holds for most phase points on the energy surface, but MITE fails to hold for any phase point.

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.

Emotional and Spiritual Quotient Approach Improve Biology Education Students’ Acceptance of Evolution Theory

NASA Astrophysics Data System (ADS)

Darussyamsu, R.; Fadilah, M.; Putri, D. H.

2018-04-01

Emotional and spiritual aspect is one of main factors that influence students’ acceptance of a theory. This study aim to measure university students’ acceptance of evolution by learns evolution using emotional and spiritual quotient (ESQ) approach. This is a quasi-experimental research using one shot case study design with the subject 36 biology educational students at Biology Department, Faculty of Mathematics and Natural Science, Universitas Negeri Padang. Data collected using the MATE instrument by Rutledge and Warden (2000) after the students learn evolution for eight meetings since January until March 2017. The result showed that by learning evolution theory combine with ESQ aspects increase students acceptance from very low become moderate acceptance. It concluded that ESQ aspects can improve students’ acceptance of evolution. Any criteria depend on it are discussed.

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.

Alternative phenotypes of male mating behaviour in the two-spotted spider mite.

PubMed

Sato, Yukie; Sabelis, Maurice W; Egas, Martijn; Faraji, Farid

2013-09-01

Severe intraspecific competition for mates selects for aggressive individuals but may also lead to the evolution of alternative phenotypes that do not act aggressively, yet manage to acquire matings. The two-spotted spider mite, Tetranychus urticae, shows male mate-guarding behaviour and male-male combat for available females. This may provide opportunity for weaker males to avoid fighting by adopting alternative mating behaviour such as sneaker or satellite tactics as observed in other animals. We investigated male precopulatory behaviour in the two-spotted spider mite by means of video-techniques and found three types of male mating behaviour: territorial, sneaker and opportunistic. Territorial and sneaker males associate with female teleiochrysales and spend much time guarding them. Territorial males are easily disturbed by rival males and engage themselves in fights with them. However, sneaker males are not at all disturbed by rival males, never engage in fights and, strikingly, never face attack by territorial males. Opportunistic males wander around in search of females that are in the teleiochrysalis stage but very close to or at emergence. To quickly classify any given mate-guarding male as territorial or sneaker we developed a method based on the instantaneous response of males to disturbance by a live male mounted on top of a brush. We tested this method against the response of the same males to natural disturbance by two or three other males. Because this method proved to be successful, we used it to collect territorial and sneaker males, and subjected them to morphological analysis to assess whether the various behavioural phenotypes are associated with different morphological characters. However, we found no statistical differences between territorial and sneaker males, concerning the length of the first legs, the stylets, the pedipalps or the body.

Hybridization, natural selection, and evolution of reproductive isolation: a 25-years survey of an artificial sympatric area between two mosquito sibling species of the Aedes mariae complex.

PubMed

Urbanelli, Sandra; Porretta, Daniele; Mastrantonio, Valentina; Bellini, Romeo; Pieraccini, Giuseppe; Romoli, Riccardo; Crasta, Graziano; Nascetti, Giuseppe

2014-10-01

Natural selection can act against maladaptive hybridization between co-occurring divergent populations leading to evolution of reproductive isolation among them. A critical unanswered question about this process that provides a basis for the theory of speciation by reinforcement, is whether natural selection can cause hybridization rates to evolve to zero. Here, we investigated this issue in two sibling mosquitoes species, Aedes mariae and Aedes zammitii, that show postmating reproductive isolation (F1 males sterile) and partial premating isolation (different height of mating swarms) that could be reinforced by natural selection against hybridization. In 1986, we created an artificial sympatric area between the two species and sampled about 20,000 individuals over the following 25 years. Between 1986 and 2011, the composition of mating swarms and the hybridization rate between the two species were investigated across time in the sympatric area. Our results showed that A. mariae and A. zammitii have not completed reproductive isolation since their first contact in the artificial sympatric area. We have discussed the relative role of factors such as time of contact, gene flow, strength of natural selection, and biological mechanisms causing prezygotic isolation to explain the observed results. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.