Search

The evolution of female mating preferences for harmful male traits is a central paradox of sexual selection.sup.1-9. Two dominant explanations for this paradox.sup.8,10 are Fisher's runaway process, which is based on genetic correlations between preference and trait.sup.1,3,4, and Zahavi's handicap principle, in which the trait is an honest costly signal of male quality.sup.2,6,8,11. However, both of these explanations require the exogenous initial spread of female preferences before harmful male traits can evolve.sup.1-4,6,8,11. Here I present a mechanism for the evolution of female mating preferences for harmful male traits that is based on the selfish evolutionary interests of sex chromosomes. I demonstrate that female-biased genetic elements--such as the W and X sex chromosomes--will evolve mating preferences for males who display traits that reduce their fitness and/or that of their male offspring, but increase fitness in female offspring. In particular, W-linked preferences can cause nearly lethal male traits to sweep to fixation. Sex-linked preferences can drive the evolution of traits such as ornamental handicaps and male parental care, and can explain variation in ornamentation and behaviour across taxa with divergent sex-determining mechanisms. Population genetic modelling shows that mate preferences encoded on sex chromosomes can drive the evolution of extremely male-costly traits., Author(s): Pavitra Muralidhar [sup.1] [sup.2] Author Affiliations: (1) Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, USA (2) Program for Evolutionary Dynamics, Harvard University, Cambridge, USA Main Female mating [...]

Environmental contamination by endocrine-disrupting chemicals (EDC) can have epigenetic effects (by DNA methylation) on the germ line and promote disease across subsequent generations. In natural populations, both sexes may encounter affected as well as unaffected individuals during the breeding season, and any diminution in attractiveness could compromise reproductive success. Here we examine mate preference in male and female rats whose progenitors had been treated with the antiandrogenic fungicide vinclozolin. This effect is sex-specific, and we demonstrate that females three generations removed from the exposure discriminate and prefer males who do not have a history of exposure, whereas similarly epigenetically imprinted males do not exhibit such a preference. The observations suggest that the consequences of EDCs are not just transgenerational but can be 'transpopulational', because in many mammalian species, males are the dispersing sex. This result indicates that epigenetic transgenerational inheritance of EDC action represents an unappreciated force in sexual selection. Our observations provide direct experimental evidence for a role of epigenetics as a determinant factor in evolution. endocrine disruption | vinclozolin | sexual selection | odor salience

This study tested two hypotheses concerning the cognitive processes underlying human mate choice in Western society: (i) mate preference is conditional in that the selectivity of individuals' mate preference is based on their perception of themselves as long-term partners, and (ii) the decision rule governing such conditional mate preference is based on translating perception of oneself on a given attribute into a comparable selectivity of preference for the same attribute in a mate. Both hypotheses were supported. A two-part questionnaire was completed by 978 heterosexual residents of Ithaca, New York, aged 18-24; they first rated the importance they placed on 10 attributes in a long-term partner and then rated their perception of themselves on those same attributes. Both women and men who rated themselves highly were significantly more selective in their mate preference. When the 10 attributes were grouped into four evolutionarily relevant categories (indicative of wealth and status, family commitment, physical appearance, and sexual fidelity), the greatest amount of variation in the selectivity of mate preference in each category was explained by self-perception in the same category of attributes. We conclude that, in Western society, humans use neither an 'opposites-attract' nor a 'reproductive-potentials-attract' decision rule in their choice of long-term partners but rather a 'likes-attract' rule based on a preference for partners who are similar to themselves across a number of characteristics. decision rules | assortative mating | marriage | reproductive success | alternative hypotheses

Indirect new data imply that mate and/or gamete choice are major selective forces driving genetic change in sexual populations. The system dictates nonrandom mating, an evolutionary process requiring both revised genetic theory and new data on heritability of characters underlying Darwinian fitness. Successfully reproducing individuals represent rare selections from among vigorous, competing survivors of preadult natural selection. Nonrandom mating has correlated demographic effects: reduced effective population size, inbreeding, low gene flow, and emphasis on deme structure. Characters involved in choice behavior at reproduction appear based on quantitative trait loci. This variability serves selection for fitness within the population, having only an incidental relationship to the origin of genetically based reproductive isolation between populations. The claim that extensive hybridization experiments with Drosophila indicate that selection favors a gradual progression of 'isolating mechanisms' is flawed, because intragroup random mating is assumed. Over deep time, local sexual populations are strong, independent genetic systems that use rich fields of variable polygenic components of fitness. The sexual reproduction system thus particularizes, in small subspecific populations, the genetic basis of the grand adaptive sweep of selective evolutionary change, much as Darwin proposed. evolution | genetic variability | natural selection I population genetics

We present a gene-culture coevolutionary model for brother-sister mating in the human. It is shown that cultural - as opposed to innate - determination of mate preference may evolve, provided the inbreeding depression is sufficiently high. At this coevolutionary equilibrium, sib mating is avoided because of cultural pressures.

The neural basis of sexual orientation in Drosophila was studied by the production of males with regionally feminized brains. Such flies express the female form of the sex determination gene transformer in a limited number of neurons under the control of GAL4 enhancer trap inserts. This method facilitated the creation of lines with a stable pattern of feminization. In tests of sexual preferences, flies that were feminized in a portion of the antennal lobes or in a subset of the corpora pedunculata (mushroom bodies) courted both males and females. These two brain structures, both of which are involved in olfactory processing, may function in the recognition of sex-specific pheromones, in the control of sex-specific behaviors, or both., In the fruit fly Drosophila melanogaster, most aspects of sexual behavior are genetically controlled [1, 2]. Sexual recognition of females by males largely relies on sexually dimorphic contact pheromones [3], [...]

A theoretical model suggests that the cause of female-driven extra-pair mating lies in the spreading of male interests among neighbouring families, creating powerful incentives for male cooperation and concomitant benefits [...]

Natural selection on mate recognition may often contribute to speciation, resulting in reproductive character displacement. Field populations of Drosophila serrata display reproductive character displacement in cuticular hydrocarbons when sympatric with Drosophila birchii. We exposed field sympatric and allopatric populations of D. serrata to experimental sympatry with D. birchii for nine generations. Cuticular hydrocarbons of field allopatric D. serrata populations evolved to resemble the field sympatric populations, whereas field sympatric D. serrata populations remained unchanged. Our experiment indicates that natural selection on mate recognition resulted in the field pattern of reproductive character displacement., A direct role for natural selection in the generation of reproductive isolation during speciation is highly controversial (1-6). Natural selection may rapidly increase divergence in mate recognition between sympatric populations [...]

The several linked polymorphic genes of the MHC, which has been proposed as a prime determinant of sensed genetic individuality within species, is known to operate in mice by olfactory recognition in aspects of reproductive behavior that concern mate selection, thereby favoring outbreeding and heterozygosity, and also concern the maintenance of pregnancy. A single base-change can alter an individual MHC odortype, and the potential range of combinatorial MHC-determined odortypes is clearly vast. Following our findings that newborn mice already express their MHC odortype (which is detectable at 9 days of gestational age), we sought to determine whether MHC is involved in behavioral aspects of early development, such as rearing. In the studies presented herein, we report the ability and proclivity of mothers to recognize and preferentially retrieve syngeneic (genetically identical) pups from other pups differing only for MHC. Reciprocally, we report the ability of pups to recognize their familial environment, regardless of whether they had been nursed by their biological mothers or by foster mothers. Early learning experiences of the MHC environment are apparently a key element in survival, assuring maternal protection and promoting outbreeding.

Monogamy is extremely rare. Of the 4,000 or so mammalian species, only a few percent are monogamous. What makes this tiny minority stay attached to one mate? Investigators are coming [...]

Female preference for secondary sexual traits in male face shape changes with the probability of conception across the menstrual cycle. Women tend to prefer male faces that are less feminized during the high-conception-risk phase than in the low-conception-risk phase. For a short-term sexual relationship, the preferred face shape is less feminine during the high-conception-risk phase, while preferences remain constant when women judge attractiveness for a long-term relationship.

In the world of fruit flies, there are no forward females. All the courting, tender touching, and serenading are done by the male; his mate's main role, like that of [...]

Every individual has a 'list' of what they do and do not want in a partner. For some people, love is the top of the list, followed by honesty and [...]

What good is a horn on a female yak (pictured, below)? Naturalists have long known that competition for mates drove the evolution of horns among male ungulates, but the presence [...]

In butterflies, the elaborate and colorful wing patterns have a number of functions, including warning signals to predators, camouflage, and thermoregulation. In many species they also serve as mate recognition [...]