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1.
Female mate choice is fundamental to sexual selection, and determining molecular underpinnings of female preference variation is important for understanding mating character evolution. Previously it was shown that whole‐brain expression of a synaptic plasticity marker, neuroserpin, positively correlates with mating bias in the female choice poeciliid, Xiphophorus nigrensis, when exposed to conspecific courting males, whereas this relationship is reversed in Gambusia affinis, a mate coercive poeciliid with no courting males. Here we explore whether species‐level differences in female behavioral and brain molecular responses represent ‘canalized’ or ‘plastic’ traits. We expose female G. affinis to conspecific males and females, as well as coercive and courting male Poecilia latipinna, for preference assays followed by whole‐brain gene expression analyses of neuroserpin, egr‐1 and early B. We find positive correlations between gene expression and female preference strength during exposure to courting heterospecific males, but a reversed pattern following exposure to coercive heterospecific males. This suggests that the neuromolecular processes associated with female preference behavior are plastic and responsive to different male phenotypes (courting or coercive) rather than a canalized response linked to mating system. Further, we propose that female behavioral plasticity may involve learning because female association patterns shifted with experience. Compared to younger females, we found larger, more experienced females spend less time near coercive males but associate more with males in the presence of courters. We thus suggest a conserved learning‐based neuromolecular process underlying the diversity of female mate preference across the mate choice and coercion‐driven mating systems.  相似文献   

2.
Although females in numerous species generally prefer males with larger, brighter and more elaborate sexual traits, there is nonetheless considerable intra‐ and interpopulation variation in mating preferences amongst females that requires explanation. Such variation exists in the Trinidadian guppy, Poecilia reticulata, an important model organism for the study of sexual selection and mate choice. While female guppies tend to prefer more ornamented males as mates, particularly those with greater amounts of orange coloration, there remains variation both in male traits and female mating preferences within and between populations. Male body size is another trait that is sexually selected through female mate choice in some species, but has not been examined as extensively as body coloration in the guppy despite known intra‐ and interpopulation variation in this trait among adult males and its importance for survivorship in this species. In this study, we used a dichotomous‐choice test to quantify the mating preferences of female guppies, originating from a low‐predation population in Trinidad, for two male traits, body length and area of the body covered with orange and black pigmentation, independently of each other. We expected strong female mating preferences for both male body length and coloration in this population, given relaxation from predation and presumably relatively low cost of choice. Females indeed exhibited a strong preference for larger males as expected, but surprisingly a weaker (but nonetheless significant) preference for orange and black coloration. Interestingly, larger females demonstrated stronger preferences for larger males than did smaller females, which could potentially lead to size‐assortative mating in nature.  相似文献   

3.
Variation in temperature can affect the expression of a variety of important fitness‐related behaviours, including those involved with mate attraction and selection, with consequences for the coordination of mating across variable environments. We examined how temperature influences the expression of male mating signals and female mate preferences—as well as the relationship between how male signals and female mate preferences change across temperatures (signal–preference temperature coupling)—in Enchenopa binotata treehoppers. These small plant‐feeding insects communicate using plantborne vibrations, and our field surveys indicate they experience significant natural variation in temperature during the mating season. We tested for signal–preference temperature coupling in four populations of E. binotata by manipulating temperature in a controlled laboratory environment. We measured the frequency of male signals—the trait for which females show strongest preference—and female peak preference—the signal frequency most preferred by females—across a range of biologically relevant temperatures (18°C–36°C). We found a strong effect of temperature on both male signals and female preferences, which generated signal–preference temperature coupling within each population. Even in a population in which male signals mismatched female preferences, the temperature coupling reinforces predicted directional selection across all temperatures. Additionally, we found similar thermal sensitivity in signals and preferences across populations even though populations varied in the mean frequency of male signals and female peak preference. Together, these results suggest that temperature variation should not affect the action of sexual selection via female choice, but rather should reinforce stabilizing selection in populations with signal–preference matches, and directional selection in those with signal–preference mismatches. Finally, we do not predict that thermal variation will disrupt the coordination of mating in this species by generating signal–preference mismatches at thermal extremes.  相似文献   

4.
The origin and maintenance of mating preferences continues to be an important and controversial topic in sexual selection research. Leks and lek‐like mating systems, where individuals gather in particular spots for the sole purpose of mate choice, are particularly puzzling, because the strong directional selection imposed by mate choice should erode genetic variation among competing individuals and negate any benefit for the choosing sex. Here, we take advantage of the lek‐like mating system of the worm pipefish (Nerophis lumbriciformis) to test the phenotype‐linked fertility hypothesis for the maintenance of mating preferences. We use microsatellite markers to perform a parentage analysis, along with a mark–recapture study, to confirm that the worm pipefish has an unusual mating system that strongly resembles a female lek, where females display and males visit the lek to choose mates. Our results show that the most highly ornamented females occupy positions near the centre of the breeding area, and males mating with these females receive fuller broods with larger eggs compared to males mating with less‐ornamented females. We also conduct a laboratory experiment to show that female ornaments are condition‐dependent and honestly signal reproductive potential. Overall, these results are consistent with the predictions of a sex‐independent version of the phenotype‐linked fertility hypothesis, as male preference for female ornaments correlates with fertility benefits.  相似文献   

5.
High male mating investment may favor selection on male mate choice particularly if females vary in quality. Terminal investment strategies constitute a maximal mating effort and have evolved independently in the absence of paternal investment in several spider taxa including the genus Argiope. To test for male mate preferences in the above context, we used the sexually cannibalistic spider A. bruennichi. We varied male state (mating status and post‐maturation age) as well as the competitive context and quantified male mate choice decisions between females of different states and developmental stages in binary choice tests. We found an overall adaptive preference for the virgin against the mated female regardless of male mating state. Furthermore, we demonstrated that older males paid more attention to female fecundity‐related traits than to mating status. In a second set of experiments, we offered males a choice between a virgin and a subadult female and varied the competitive context which had no effect on male decisions. Curiously, a preference for the virgin adult female was only apparent after exclusion of females that matured <3 d prior to the test. Repeated tests of males supported the hypothesis that males do not distinguish between a freshly matured virgin female and a subadult female. Our results show that male spiders execute mate choice based on information collected from female silk strands and that they integrate their own state into mating decisions.  相似文献   

6.
Perceptual biases explain the origin and evolution of female preference in many species. Some responses that mediate mate choice, however, may have never been used in nonmating contexts. In the fiddler crab, Uca mjoebergi, mate‐searching females prefer faster wave rates and leading wave; however, it remains unclear whether such responses evolved in a mating context (i.e., the preference has effect on the fitness of the female and her offspring that arise from mating with a particular male) or a nonmating contexts (i.e., a female obtains direct benefits through selecting the male with a more detectable trait). Here, we compared the preferences of mate‐searching with those of ovigerous females that are searching for a burrow and do not concern about male “quality.” Results showed that as both mate‐searching and ovigerous females preferentially approached robotic males with faster wave rates. This suggests that wave rate increases detectability/locatability of males, but the mating preference for this trait is unlikely to evolve in the mating context (although it may currently function in mate choice), as it does not provide fitness‐related benefit to females or her offspring. Wave leadership, in contract, was attractive to mate‐searching females, but not ovigerous females, suggesting that female preference for leadership evolves because wave leadership conveys information about male quality. We provide not only an empirical evidence of sensory biases (in terms of the preference for faster wave), but the first experimental evidence that mating context can be the only selection force that mediates the evolution of male sexual traits and female preference (in terms of the preference for leading wave).  相似文献   

7.
Mate sampling and the sexual conflict over mating in seaweed flies   总被引:3,自引:1,他引:2  
The order in which females encounter, or sample, males in apopulation may have important consequences for mate choice,with the information gathered about males influencing boththe preference function and degree of choosiness of females.Sexual selection may be affected as a result. Sampling of particularsubsets of males may be a crucial component of individual variation in mate preferences within populations. However, the sequencein which males are sampled may also be important in specieswithout traditional, active mate choice, such as when sexualselection involves sexual conflict over mating. This wouldoccur if the likelihood of a female mating with a male of acertain phenotype changes as a result of previous encounters.We examined the effects of encountering males differing inbody size, a sexually selected phenotype, in the seaweed flyCoelopa frigida. Sexual selection occurs in this species asa result of a sexual conflict over mating. We show that theoutcome of the sexual conflict is independent of the orderin which males are encountered by female seaweed flies, withthe overall mating advantage to large males being unaffected.In addition, we explored female preference functions and evaluatethe heterogeneity in female willingness to mate. We suggestthat consideration of mate sampling theory is valuable whenexamining mate choice in species in which sexual selectionis driven by sexual conflict.  相似文献   

8.
All too often, studies of sexual selection focus exclusively on the responses in one sex, on single traits, typically those that are exaggerated and strongly sexually dimorphic. They ignore a range of less obvious traits and behavior, in both sexes, involved in the interactions leading to mate choice. To remedy this imbalance, we analyze a textbook example of sexual selection in the stalk‐eyed fly (Diasemopsis meigenii). We studied several traits in a novel, insightful, and efficient experimental design, examining 2,400 male–female pairs in a “round‐robin” array, where each female was tested against multiple males and vice versa. In D. meigenii, females exhibit strong mate preference for males with highly exaggerated eyespan, and so we deliberately constrained variation in male eyespan to reveal the importance of other traits. Males performing more precopulatory behavior were more likely to attempt to mate with females and be accepted by them. However, behavior was not a necessary part of courtship, as it was absent from over almost half the interactions. Males with larger reproductive organs (testes and accessory glands) did not make more mating attempts, but there was a strong tendency for females to accept mating attempts from such males. How females detect differences in male reproductive organ size remains unclear. In addition, females with larger eyespan, an indicator of size and fecundity, attracted more mating attempts from males, but this trait did not alter female acceptance. Genetic variation among males had a strong influence on male mating attempts and female acceptance, both via the traits we studied and other unmeasured attributes. These findings demonstrate the importance of assaying multiple traits in males and females, rather than focusing solely on prominent and exaggerated sexually dimorphic traits. The approach allows a more complete understanding of the complex mating decisions made by both males and females.  相似文献   

9.
Speciation processes initiated by divergent selection often fail to complete; yet, how sexual selection is involved in the progress of ecological speciation is rarely understood. Intraspecific body‐size variation affects mate preference and male–male competition, which can consequently lead to assortative mating based on body size. In the present study, we tested the importance of body size difference in the potential of assortative mating between the two eastern newt subspecies, larger Notophthalmus viridescens viridescens and smaller Notophthalmus viridescens dorsalis. Through differential expression of life‐cycle polyphenism, these two subspecies are adapted to contrasting environments, which has likely led to the subspecific body‐size difference. We found that males of both subspecies preferred larger females of N. v. viridescens as mates presumably because of the fecundity advantage of larger females. On the other hand, no evidence of female choice was found. Larger males of N. v. viridescens exhibited greater competitive ability and gained primary access to larger females of their own kind. However, smaller males were able to overcome their inferior competitive ability by interfering with larger males' spermatophore transfer and sneakily mating with larger females. Thus, the subspecific body‐size difference importantly affected sexual selection processes, resulting in nonrandom but not completely assortative mating patterns between the larger and smaller subspecies. Although life‐cycle polyphenism facilitates the intraspecific ecological divergence within N. v. viridescens sexual selection processes, namely smaller males' mate preference for larger females and sexual interference during spermatophore transfer, may be halting completion of the ecological speciation. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 884–897.  相似文献   

10.
The lek paradox asserts that strong directional selection via female choice should deplete additive genetic variation in fitness and consequently any benefit to females expressing the preference. Recently, we have provided a novel resolution to the paradox by showing that nonadditive genetic effects such as overdominance can be inherited from parent to offspring, and populations with females that express a mating preference for outbred males maintain higher genetic variation than populations with females that mate randomly. Here, we test our dynamic model using empirical data previously published from a small island population of song sparrows (Melospiza melodia). The model assumes that fitness and male trait expression display overdominance effects. The results demonstrate that female choice for outbred males mediated by directional selection on song repertoire size provides a heritable benefit to offspring through reduced inbreeding depression. Within the population, we estimate the heritability of the inbreeding coefficient to be 0.18 ± 0.08 (SD). Furthermore, we show that mate choice for outbred males increases fitness‐related genetic variation in the population by 12% and thereby reduces inbreeding depression by 1% per generation in typical years and upwards of 15% in severe years. Thus, mate choice may help to stave off population extinction in this and other small populations.  相似文献   

11.
Color polymorphisms are associated with variation in other traits which may affect individual fitness, and these color‐trait associations are expected to contribute to nonrandom mating in polymorphic species. The red‐backed salamander (Plethodon cinereus) exhibits a polymorphism in dorsal pattern: striped and unstriped, and previous studies have suggested that they may mate nonrandomly. However, the mechanism(s) contributing to this behavior remain unclear. Here we consider the role that male preference may have in driving mating behavior in P. cinereus. We limit our focus to striped individuals because this morph is most likely to be choosy given their dominant, aggressive behavioral profiles relative to unstriped males. Specifically, we evaluated (a) whether striped males preferentially associate with females with respect to her dorsum color, size, and body condition and (b) if so, whether female traits are evaluated via visual or chemical cues. We also considered whether the frequency of another male social behavior, nose taps, was associated with mate preferences. We found that striped male P. cinereus nose tapped more often to preferred females. However, males only assessed potential mates via chemical cues, preferring larger females overall. Reproductive phenology data on a sample of gravid females drawn from the same population indicated that the color morphs do not differ in reproductive traits, but larger females have greater fecundity. Given our findings, we conclude that female P. cinereus are under fecundity selection, mediated by male preference. In this manner, male mating behavior contributes to observations of nonrandom mate associations in this population of P. cinereus.  相似文献   

12.
Mate choice for novel partners should evolve when remating with males of varying genetic quality provides females with fitness‐enhancing benefits. We investigated sequential mate choice for same or novel mating partners in females of the cellar spider Pholcus phalangioides (Pholcidae) to understand what drives female remating in this system. Pholcus phalangioides females are moderately polyandrous and show reluctance to remating, but double‐mated females benefit from a higher oviposition probability compared to single‐mated females. We exposed mated females to either their former (same male) or a novel mating partner and assessed mating success together with courtship and copulatory behaviours in both sexes. We found clear evidence for mate discrimination: females experienced three‐fold higher remating probabilities with novel males, being more often aggressive towards former males and accepting novel males faster in the second than in the first mating trial. The preference for novel males suggests that remating is driven by benefits derived from multiple partners. The low remating rates and the strong last male sperm precedence in this system suggest that mating with novel partners that represent alternative genotypes may be a means for selecting against a former mate of lower quality.  相似文献   

13.
Ecological speciation is facilitated when divergent adaptation has direct effects on selective mating. Divergent sensory adaptation could generate such direct effects, by mediating both ecological performance and mate selection. In aquatic environments, light attenuation creates distinct photic environments, generating divergent selection on visual systems. Consequently, divergent sensory drive has been implicated in the diversification of several fish species. Here, we experimentally test whether divergent visual adaptation explains the divergence of mate preferences in Haplochromine cichlids. Blue and red Pundamilia co‐occur across south‐eastern Lake Victoria. They inhabit different photic conditions and have distinct visual system properties. Previously, we documented that rearing fish under different light conditions influences female preference for blue versus red males. Here, we examine to what extent variation in female mate preference can be explained by variation in visual system properties, testing the causal link between visual perception and preference. We find that our experimental light manipulations influence opsin expression, suggesting a potential role for phenotypic plasticity in optimizing visual performance. However, variation in opsin expression does not explain species differences in female preference. Instead, female preference covaries with allelic variation in the long‐wavelength‐sensitive opsin gene (LWS), when assessed under broad‐spectrum light. Taken together, our study presents evidence for environmental plasticity in opsin expression and confirms the important role of colour perception in shaping female mate preferences in Pundamilia. However, it does not constitute unequivocal evidence for the direct effects of visual adaptation on assortative mating.  相似文献   

14.
We investigated the mechanisms of sexual selection operating on body size in the one‐sided livebearer (Jenynsia multidentata), a small fish characterized by male dwarfism. Mating in the one‐sided livebearer is coercive: males approach females from behind and try to thrust their copulatory organ at the female genital pore. Females counter males' mating attempts by either swimming away or attacking them. We tested the hypothesis that the components of sexual selection favouring small size in males (sexual coercion) were more effective than those favouring a large size (male competition and mate choice). When alone, small males had a significantly higher success in their mating attempts than large males. The proportion of successful attempts was also positively correlated with female size. When two males competed for the same female, the large male had a significant mating advantage over the small one. With a 1 : 1 sex ratio, the large‐male mating advantage vanished because each male tended to follow a different female. Large males, however, preferentially defended large females, thus compelling small males to engage with smaller, less fecund females. Males did not discriminate between gravid and non‐gravid females, but preferred mating with larger females. This preference disappeared when males were much smaller than the female, probably in relation to the risk for the male of being eaten or injured by the female. In a choice chamber, male‐deprived females that had their sperm storage depleted remained close to males and showed a preference for large individuals, a behaviour not observed in non‐deprived females. Nonetheless, when placed with males in the same aquarium, all females showed avoidance and aggression. Struggling may represent a way by which the female assesses the skill and endurance of males.  相似文献   

15.
Female multiple mating (polyandry) is widespread across Insecta, even if mating can be costly to females. To explain the evolution and maintenance of polyandry, several hypotheses, mainly focusing on the material (direct) and/or the genetic (indirect) benefits, have been proposed and empirically tested in many species. Considering only the direct benefits, repeatedly‐mated females are expected to exhibit the same fitness as multiply‐mated females under the same mating frequency. In the present study, we compare the fitness of females received monandrous repeated mating (MM) and polyandrous multiple mating (PM) in a polyandrous leaf beetle Galerucella birmanica and assess female mate preference with regard to polyandry or monandry. Our data indicate that the longevity and the egg‐laying duration of MM females are significantly longer than that of PM females. MM females produce significantly more hatched eggs than PM females over their lifetime under the same mating frequency, which results from the high hatching rate of eggs produced by MM females. PM females mated with novel virgin males in the second mating suffer decreased longevity and lifetime fecundity compared with PM females mated with novel mated males in the second mating. Once‐mated females are more likely to re‐mate with familiar males than novel males. By contrast to expectations, the results of the present study suggest that repeated mating provides females with more direct benefits than multiple mating in G. birmanica, and females prefer to re‐mate with familiar males. The possible causes of this finding are discussed.  相似文献   

16.
Mate choosiness by males has been documented in many taxa but we still do not know how it varies with age even though such variation can be important for our understanding of sexual selection on females. Theory provides conflicting predictions: young males, who are less attractive to females than older males, may be less choosy, or older males, who face fewer expected future mating opportunities, may be less choosy. In our experiments with fruit flies (Drosophila melanogaster), young (1‐d‐old) males spent relatively less time courting recently mated females than did mature (4‐d‐old) males. Overall, there was a gradual decline in male mate choosiness from age 1–7 d. As male age was correlated with the duration of deprivation from females, we tested for the effect of deprivation and found that same‐age males previously exposed to females were choosier than female‐deprived males. We also assessed key male parameters that could affect choosiness and found that, compared to mature males, young males were less attractive to females, less competitive in intramale interactions and less fertile. Although the lesser attractiveness and competitiveness should select for lesser mate choosiness in young males, their limited fertility and more expected future mating opportunities seem to override the other factors and lead to high mate choosiness in young males. Overall, our data indicate that young males just after reaching sexual maturity are choosy and that subsequent exposure to females can maintain high levels of male mate choosiness with age. Hence, males can contribute much more to sexual selection than previously appreciated.  相似文献   

17.
In sex‐role‐reversed species, sexual selection acts more strongly on females than on males, a situation that can result in the evolution of secondary sexual traits in females and strong mating preferences in males. While some research exploring mating preferences in sex‐role‐reversed species has been conducted, overall, this topic remains relatively unexplored. The Gulf pipefish, Syngnathus scovelli, is a highly polyandrous pipefish species. Sexual selection is significantly stronger in females than in males, which has led to the evolution of both morphological and behavioral female secondary sexual traits. However, because males gestate the offspring in specialized pouches and make a substantial investment in embryos during development, females may also benefit from being choosy. The goal of this study was to examine both male and female mating preferences in this species. We found that male mating preference was significantly associated with female courtship behavior. Larger females were also able to maintain these behaviors for longer intervals than smaller females. No evidence of female mating preference in regard to male size was observed but the data suggest that male behaviors may be providing positive reinforcement to courting females. This research provides further insight into how mate preferences vary among sex‐role‐reversed species.  相似文献   

18.
Genetic diversity is a key factor that can influence mate choice in many species. We experimentally determined the influence of this factor on mate preference in the crustacean terrestrial isopod Armadillidium vulgare. This biological model is gregarious which could increase the risk of inbreeding by mating with closely related partners. Mechanisms of inbreeding avoidance during mate choice can thus be expected. Moreover, previous studies predict that males would be the choosy sex. We performed Y‐choice tests giving males the choice between two females presenting different levels of heterozygosity and genetic similarity to the male. Our results show potential inbreeding avoidance according to the genetic characteristics of females presented to males. The higher the variation in genetic similarity to the male between females is, the higher the preference of the male towards the most dissimilar female is. Hence, male preferences may only be detectable when the difference between females’ genetic characteristics is large enough. If heterozygosity is associated with fitness in A. vulgare (as in many organisms), the patterns of mate preference we observe may be adaptive.  相似文献   

19.
Most hypotheses to explain nonrandom mating patterns invoke mate choice, particularly in species that display elaborate ornaments. However, conflicting selection pressures on traits can result in functional constraints that can also cause nonrandom mating patterns. We tested for functional load‐lifting constraints during aerial copulation in Rhamphomyia longicauda, a species of dance fly that displays multiple extravagant female‐specific ornaments that are unusual among sexual traits because they are under stabilizing selection. R. longicauda males provide females with a nuptial gift before engaging in aerial mating, and the male bears the entire weight of the female and nuptial gift for the duration of copulation. In theory, a male's ability to carry females and nuptial gifts could constrain pairing opportunities for the heaviest females, as reported for nonornamented dance flies. In concert with directional preferences for large females with mature eggs, such a load‐lifting constraint could produce the stabilizing selection on female size previously observed in this species. We therefore tested whether wild‐caught male R. longicauda collected during copulation were experiencing load‐lift limitations by comparing the mass carried by males during copulation with the male's wing loading traits. We also performed permutation tests to determine whether the loads carried by males during copulation were lighter than expected. We found that heavier males are more often found mating with heavier females suggesting that whereas R. longicauda males do not experience a load‐lift constraint, there is a strong relationship of assortative mating by mass. We suggest that active male mate choice for intermediately adorned females is more likely to be causing the nonrandom mating patterns observed in R. longicauda.  相似文献   

20.
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.  相似文献   

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