Female Sailfin Mollies Research Articles

Phenotypic plasticity in the sailfin molly III: Geographic variation in reaction norms of growth and maturation to temperature and salinity.

Phenotypic plasticity, the ability of a single genotype to produce different phenotypes under different environmental conditions, plays a profound role in several areas of evolutionary biology. One important role is as an adaptation to a variable environment. While plasticity is extremely well documented in response to many environmental factors, there is controversy over how much of that plasticity is adaptive. Evidence is also mixed over how often conspecific populations display qualitative differences in the nature of plasticity. We present data on the reaction norms of growth and maturation to variation in temperature and salinity in male and female sailfin mollies (Poecilia latipinna) from three locally adjacent populations from South Carolina (SC). We compare these reaction norms to those previously reported in locally adjacent populations from north Florida (NF). In general, patterns of plasticity in fish from SC were similar to those in fish from NF. The magnitude of plasticity differed; fish from SC displayed less plasticity than fish from NF. This was because SC fish grew faster and matured earlier at the lower temperatures and salinities compared to NF fish. This is a countergradient pattern of variation, in which SC fish grew faster and matured earlier in conditions that would otherwise slow growth and delay maturity. Among fish from both regions, males were much less plastic than females, especially for length at maturity. While there was no detectable heterogeneity among populations from NF, males from one of the SC populations, which is furthest from the other two, displayed a qualitatively different response in age at maturity to temperature variation than did males from the other two SC populations. The pattern of population variation in plasticity within and among regions suggests that gene flow, which diminishes with distance in sailfin mollies, plays a critical role in constraining divergence in norms of reaction.

Size, species and audience type influence heterospecific female–female competition

Female–female competition for mates can be as intense as male–male competition, but it has received little attention until recently. Typically, such competition is expressed as context-dependent aggressive encounters between individuals of the same species within a complex social environment. Unlike male competition, in cases of sexual parasitism, female competition includes important heterospecific interactions. We explore how competitor body size and species influence female–female aggression in a sexual–unisexual mating system where heterospecific females compete for males of the sexual species. Specifically, we examined whether (1) the size and species of female competitors and (2) the sex and species of an audience influence female–female aggression in sailfin mollies, Poecilia latipinna. We found that competitor body size had a secondary effect on the amount of aggression a female performed when compared to the species of her female competitor. Female sailfin mollies were more aggressive towards conspecifics than they were towards Amazon mollies, Poecilia formosa, especially in front of a sailfin molly male and female audience. These results demonstrate that the social environment greatly influences how females regulate their aggressive behaviours, and they highlight not only the role of female competition for males, but also the importance of understanding the impact of the social environment on female competition.

Sex differences in color discrimination and serial reversal learning in mollies and guppies.

Behavioral flexibility provides an individual with the ability to adapt its behavior in response to environmental changes. Studies on mammals, birds, and teleosts indicate greater behavioral flexibility in females. Conversely, males appear to exhibit greater behavioral persistence. We, therefore, investigated sex differences in behavioral flexibility in 2 closely related molly species (Poecilia latipinna, P. mexicana) and their more distant relative, the guppy P. reticulata by comparing male and female individuals in a serial, visual reversal learning task. Fish were first trained in color discrimination, which was quickly learned by all females (guppies and mollies) and all molly males alike. Despite continued training over more than 72 sessions, male guppies did not learn the general test procedure and were, therefore, excluded from further testing. Once the reward contingency was reversed serially, molly males of both species performed considerably better by inhibiting their previous response and reached the learning criterion significantly faster than their respective conspecific females. Moreover, Atlantic molly males clearly outperformed all other individuals (males and females) and some of them even reached the level of 1-trial learning. Thus, the apparently universal pattern of higher female behavioral flexibility seems to be inverted in the 2 examined molly species, although the evolutionary account of this pattern remains highly speculative. These findings were complemented by the observed lower neophobia of female sailfin mollies compared with their male conspecifics. This sex difference was not observed in Atlantic mollies that were observed to be significantly less distressed in a novel situation than their consexuals. Hypothetically, sex differences in behavioral flexibility can possibly be explained in terms of the different roles that males and females play in mating competition, mate choice, and reproduction or, more generally, in complex social interactions. Each of these characteristics clearly differed between the closely related mollies and the more distantly related guppies.

Individual variation in ACTH-induced cortisol levels in females of a livebearing fish at different gestational stages

Individuals vary in their baseline levels of stress hormones (predictive homeostasis) and in their stress responses (reactive homeostasis). Variation in normal reactive scope, both predictive and reactive homeostasis, may be important for understanding how endocrine traits respond to selection. Reactive homeostasis is the increase in glucocorticoid (GCs) hormones above baseline. Individuals at different life history stages, such as gestation in females, may show variation in normal reactive scope. We performed an adrenocorticotropic hormone (ACTH) challenge and measured changes in circulating GCs to estimate the reactive scope of female sailfin mollies (Poecilia latipinna) at different gestational states. We measured cortisol, primary GC in teleost fishes, to obtain baseline release rates prior to injection with either ACTH or saline control. Using water-borne hormones, we measured cortisol release rates at four time intervals post-injection. Females were then sacrificed to determine the developmental stage of embryos, if present, and the number of developing embryos or mature ova. We found that ACTH-injected females had significant increases in cortisol releases rates, whereas cortisol release rates of control females did not change during the 4 h post-injection period. We found high repeatability in predictive homeostasis of cortisol and moderate repeatability in reactive homeostasis and a phenotypic correlation between predictive and reactive homeostasis. Gestational state did not affect female predictive or reactive homeostasis. We applied the reactive scope model to P. latipinna and gained a further understanding of how among- and within-individual variation in both predictive and reactive homeostasis are partitioned and how these traits vary under certain life-history conditions.

Mate-choice copying in sailfin molly females: public information use from long-distance interactions

Animals may use public information gained by observing sexual interactions between conspecifics and use this information for their own mate choice. This strategy, called mate-choice copying, is considered to play an important role for the evolution of mate preferences. Mate-choice copying is defined as non-independent mate choice, in which a female’s probability of choosing a given male increases if other females have chosen that male previously. Using the livebearing sailfin molly (Poecilia latipinna), we asked if increasing the distance between a model female and a male would affect copying behaviour of focal females. We tested focal females in two different treatments: (1) model female and male in close proximity and able to interact at close range and (2) model female and male positioned apart from each other and restricted from close-range interactions. We could show that focal females copied the choice of a model at short distance to the prior non-preferred male as predicted from previous experiments. Surprisingly, focal females also copied the choice of a model when positioned 40 cm apart from the male. When no model female and, hence, no public information were provided (choice consistency control), focal females were consistent in their mate choice, indicating that changes in mate preference observed in the two treatments were due to the simulated mate choice of the model female. Our results demonstrate that females gain and use public information and copy the mate choice of other females even when heterosexual conspecifics interact from a distance. Animals can copy the mate choice of conspecifics by observing their sexual interactions and, hence, choose the same mate as the other individual did before. So far, mate-choice copying was investigated when the so-called model female and the male were in close proximity. Here, we investigated whether female sailfin mollies (Poecilia latipinna) copy the choice of a model female for a male when the model female can only interact with a male at distance. We show for the first time that even interactions of heterosexual conspecifics at distance provide public information for an observing focal female to copy the choice of the model. Our results imply an even wider information transfer in sailfin molly social networks than previously thought.

A potential role of male and female androgen in species recognition in a unisexual–bisexual mating complex

Hormones play a critical role in the regulation of vertebrate mating behavior, including receptivity, and several components of mate choice. However, less is known about the role of these chemical messengers in mediating behavior associated with premating reproductive isolation. The bisexual–unisexual mating complex of sailfin mollies, Poecilia latipinna, and Amazon mollies, Poecilia formosa (sexual parasites of sailfins) has been a model system for studying ultimate mechanisms of species recognition. However proximate mechanisms, such as variation in hormone levels, have not been examined. We paired male sailfin mollies with either female conspecifics or Amazon mollies and obtained water-borne hormone samples before and after mating for all fish. We measured 11-ketotestosterone, testosterone, and estradiol from the water samples. As expected from previous studies, males mated with conspecifics more frequently than with Amazon mollies. 11-Ketotestosterone production by males increased when they mated with female sailfin mollies who themselves also showed elevated production of 11-ketotestosterone. This increase in male and female 11-ketotestosterone levels was not seen when males mated with Amazon mollies. This unique endocrine interaction represents a potential proximate mechanism for species recognition by male sailfin mollies. We found no significant change in testosterone or estradiol under these conditions suggesting that a single hormone mediates bidirectional interactions between males and females during courtship.

Variation in male sailfin molly, preference for female size: does sympatry with sexual parasites, drive preference for smaller conspecifics?

Male sailfin mollies (Poecilia latipinna) are sexually parasitized by gynogenetic Amazon mollies (Poecilia formosa). In areas of sympatry, Amazon mollies are frequently larger than female sailfin mollies. In sympatry, selection may favor males that prefer smaller conspecific mates (avoid mismating with Amazon mollies), or selection may favor males that prefer larger conspecific mates (higher fecundity). To explore this potential species and mate-quality recognition conflict, we examined male preference variation across populations. Males from one sympatric population showed stabilizing preference functions, whereas in another sympatric population, males showed directional preference functions. Variation across sympatric populations may be related to the length of time of co-evolution with Amazon mollies. In the allopatric populations, we found flat preference functions. Variation in male preferences could have important ramifications for the maintenance of Amazon mollies, as well as for the evolution of female size.

Association preferences of unisexual Amazon mollies (Poecilia formosa): differential response to swords based on sex of the bisexual parental species

Most females exhibit preferences for certain males and females based on mating and social decisions. Unisexual females that reproduce by gynogenesis are also expected to express association preferences, which may have been inherited from parental species, or may have evolved in response to selection pressures associated with their unisexual mating system. The unisexual, gynogenetic Amazon molly (Poecilia formosa) is a hybrid of the Atlantic molly (P. mexicana) and sailfin molly (P. latipinna). Although none of these three species have sword tails, the two parental species differ in preference for swords on conspecifics. We further examined the variation in pre-existing bias within this species complex by testing Amazon molly preference to associate with male and female sailfin mollies with artificially attached swords. Amazon mollies significantly avoided females with colored swords, but were indiscriminate towards swords on males. Thus, this hybrid species shares its lack of preference for swords on males with female Atlantic mollies and females from one population of sailfin mollies. Avoidance of females with swords by Amazon mollies is unique in this species complex. We discuss the implications and functions of association preferences expressed by Amazon mollies and propose hypotheses for the differential response towards swords based on sex.

Non-repeatable mate choice by male sailfin mollies, Poecilia latipinna, in a unisexual-bisexual mating complex

Most studies of repeatability examine female mate choice, but male mate choice may have significant evolutionary consequences when males of a sexual species are sexually parasitized by heterospecific gynogenetic females as is the case for sailfin mollies, Poecilia latipinna. Amazon mollies, Poecilia formosa, are all female gynogens that require sperm from P. latipinna for initiation of embryogenesis, but inheritance is strictly maternal. We examined repeatability and consistency of male mate choice for female sailfin versus Amazon mollies in a series of 4 experiments. We measured male association preference for 1) size-matched female sailfin versus Amazon mollies, 2) smaller female sailfin mollies versus larger Amazon mollies, and 3) larger female sailfin mollies versus smaller Amazon mollies. We also examined 4) actual male mate choice for size-matched sailfin versus Amazon mollies. Male mate preference was not repeatable in any of our studies, and male sailfin mollies were consistent in their mate preference for conspecific females over heterospecific females only when the conspecific female was larger than the Amazon and when males could actually mate with females of both species. In all experiments, males that showed the highest conspecific preference also showed the most consistency in their preference across the 2 days of testing. The lack of repeatability of male mate preference may contribute to the persistence of Amazon mollies.

Differential sperm expenditure by male sailfin mollies, Poecilia latipinna, in a unisexual–bisexual species complex and the influence of spermiation during mating

Selection should favor strategies that reduce costs associated with spermatogenesis. This is especially true when males are sympatric with closely related species, and must avoid heterospecific matings, as in the unisexual–bisexual species complex of mollies. Male sailfin mollies, Poecilia latipinna, are sexually parasitized by Amazon mollies (P. formosa), and produce more sperm in the presence of female sailfin mollies than in the presence of Amazon mollies. We tested the hypothesis that male sailfin mollies differentially expend sperm when mating with either conspecific or heterospecific females. We measured sperm expenditure by determining the amount of sperm males have remaining after mating. Male sailfin mollies had more sperm available after mating with female sailfin mollies than after mating with Amazon mollies. While this result could indicate higher sperm expenditure to Amazon mollies, males mating with female sailfin mollies had more sperm available after mating than their baseline sperm reserves. Spermiation, the last stage of spermatogenesis, could be triggered by physical contact with females, and could increase sperm availability during mating. We examined the relationship between sperm availability and the amount of time that males mated with females. We found that sperm availability increased as mating trial time increased with female sailfin mollies, but not with Amazon mollies. Spermiation in the presence of conspecific female stimuli could reduce physiological costs associated with spermatogenesis while increasing the amount and quality of sperm available for sperm competition. We suggest that future studies examining sperm priming and expenditure should consider the potential for spermiation.

Do I Know You? Species Recognition Operates Within and Between the Sexes in a Unisexual–Bisexual Species Complex of Mollies

AbstractMale sailfin mollies (Poecilia latipinna) can be sexually parasitized by closely related, unisexual, gynogenetic Amazon mollies (Poecilia formosa). This study examined possible cues used by male P. latipinna to distinguish between conspecific females and sympatric, heterospecific P. formosa. Digital photos were used to create models to test male P. latipinna preference for model female P. latipinna and P. formosa with a full suite of traits and altered models of P. latipinna and P. formosa. Male P. latipinna significantly preferred models of either species over no stimulus, demonstrating that models elicit a male response. Males also significantly preferred female P. latipinna models over P. formosa models. We also examined species recognition by female sailfin mollies using the same models, and found that female sailfin mollies significantly preferred to associate with female P. latipinna over P. formosa. These results taken together suggest that the use of fish models yield results similar to those studies using live stimuli. Male preference was then tested for unaltered vs. altered models in the following combinations: (i) P. formosa vs. P. formosa with a female P. latipinna fin; (ii) P. formosa vs. P. formosa with a female P. latipinna lateral spot pattern; (iii) P. formosa vs. P. latipinna with a P. formosa fin and their spotless lateral pattern. Males did not significantly prefer models with any isolated traits over the unaltered P. formosa models. Thus, males may be using traits other than the ones isolated for species recognition or males may be using a suite of multiple traits to recognize conspecific females.

The effects of male proximity, apparent size, and absolute size on female preference in the sailfin molly, Poecilia latipinna

[Female sailfin mollies (Poecilia latipinna) prefer males of greater lateral projection area. This preference may reflect perceptual constraints on the female. A larger male may project a larger image onto the female's retina at a given viewing distance. This may elicit greater stimulation of the visual system and thus a stronger behavioral response. This study investigates the effects of male proximity, apparent size, and absolute size on female preference in sailfin mollies. I examine whether females base their mate preferences on the male's actual size, or on the size of the image he projects on the female's retina (apparent size). The question of actual vs apparent size preferences in fish has been addressed within the context of optimal prey-size selection, but this study is believed to be the first to examine the question in the context of sexual selection. I presented females with pairs of dummy males in seven treatments organized into four categories: (1) The Actual Size Control — a single treatment where male actual size was held constant while varying female viewing distance; (2) The Distance Controls — three treatments in which male distance from the female subject was held constant, while varying actual size; (3) The Apparent Size Controls — two treatments where both body size and viewing distances varied, while holding apparent size constant; and (4) The Experimental treatment — a single test in which the smaller male of the pair appeared larger. In each of the Actual Size and Distance Control treatments, females preferred the closer and larger males, respectively. However, females exhibited no preferences in either of the Apparent Size Control treatments. Additionally, females in the Experimental treatment preferred the apparently larger dummy to the male that was actually larger. These results suggest that female preference for male size is based on the male's apparent size — i.e., that preference is based on the size of the image projected on the female's retina, rather than the male's actual body size. The evolutionary implications of these results with regard to courtship strategies and male secondary sex traits are discussed., Female sailfin mollies ( Poecilia latipinna ) prefer males of greater lateral projection area. This preference may reflect perceptual constraints on the female. A larger male may project a larger image onto the female's retina at a given viewing distance. This may elicit greater stimulation of the visual system and thus a stronger behavioral response. This study investigates the effects of male proximity, apparent size, and absolute size on female preference in sailfin mollies. I examine whether females base their mate preferences on the male's actual size, or on the size of the image he projects on the female's retina (apparent size). The question of actual vs apparent size preferences in fish has been addressed within the context of optimal prey-size selection, but this study is believed to be the first to examine the question in the context of sexual selection. I presented females with pairs of dummy males in seven treatments organized into four categories: (1) The Actual Size Control — a single treatment where male actual size was held constant while varying female viewing distance; (2) The Distance Controls — three treatments in which male distance from the female subject was held constant, while varying actual size; (3) The Apparent Size Controls — two treatments where both body size and viewing distances varied, while holding apparent size constant; and (4) The Experimental treatment — a single test in which the smaller male of the pair appeared larger. In each of the Actual Size and Distance Control treatments, females preferred the closer and larger males, respectively. However, females exhibited no preferences in either of the Apparent Size Control treatments. Additionally, females in the Experimental treatment preferred the apparently larger dummy to the male that was actually larger. These results suggest that female preference for male size is based on the male's apparent size — i.e., that preference is based on the size of the image projected on the female's retina, rather than the male's actual body size. The evolutionary implications of these results with regard to courtship strategies and male secondary sex traits are discussed.]

Differences in female preference for male body size in Poecilia latipinna using simultaneous versus sequential stimulus presentation designs

Female sailfin mollies (Poecilia latipinna) were presented simultaneously with a series of dummy male pairs that differed only in male body size (with dorsal fin size held constant). Females showed a significant directional preference for males of larger body size. However, when presented with the same five dummies in sequence, the same females showed a much weaker preference for increased male body size. To our knowledge, this study is the first of its kind to present to the same females the same set of stimuli in both sequential and paired fashion. Our results showed that females exhibit a much stronger preference for larger males presented simultaneously than when presented in sequence. Female sailfin mollies may therefore more strongly prefer larger males when they can make direct and immediate comparisons between them. These results highlight the importance of considering how females encounter potential mates in nature when designing experiments on female preference in a given species. They also emphasize how the distribution and local density of prospective mates and the context in which they are presented may influence mate choice and sexual selection in general.

The role of model female quality in the mate choice copying behaviour of sailfin mollies

Female mate choice copying is a socially mediated mate choice behaviour, in which a male's attractiveness to females increases if he was previously chosen by another female as a mate. Although copying has been demonstrated in numerous species, little is known about the specific benefits it confers to copying females. Here we demonstrate that the mate choice behaviour of female sailfin mollies (Poecilia latipinna) is influenced by the phenotypic quality of model females with whom males are observed consorting. Test females choosing between two males of similar body length were found to significantly increase time spent with previously non-preferred males after having observed them with a relatively high-quality female. Conversely, females were found to significantly decrease time spent with previously preferred males after having observed them with a relatively low-quality female. Female mate choice copying might be maintained by selection based on the heuristic value it provides females choosing between males whose quality differences are not easily distinguishable.

Asexuals looking for sex: conflict between species and mate-quality recognition in sailfin mollies (Poecilia latipinna)

When two closely related species are sympatric the process of species recognition (identifying conspecifics) and mate-quality recognition (increased fitness benefits) can yield a conflict when heterospecifics resemble high-quality conspecifics. Conflict in species versus mate-quality recognition may serve as a possible mechanism for the persistence of unisexual, gynogenetic Amazon mollies (Poecilia formosa). Amazon mollies require sperm from closely related species (e.g., sailfin mollies, P. latipinna) to start embryogenesis but inheritance is strictly maternal. When choosing mates, male sailfin mollies from populations sympatric with Amazon mollies may rely on traits indicating species identity rather than those indicating mate quality. Conversely, males from allopatric populations may rely more on traits indicating mate quality. Previous work has found that male sailfin mollies in sympatry exhibit a significantly greater mating preference for female sailfin mollies over Amazon mollies compared to males in allopatry. In addition, male sailfin mollies prefer to associate with and produce more sperm in the presence of larger conspecific females, which are more fecund. We hypothesized that male sailfin mollies experience a conflict in species recognition and mate-quality recognition in the presence of Amazon mollies that are relatively larger than female sailfin mollies. To test this hypothesis, we paired males from sympatric and allopatric populations with a larger Amazon molly and a smaller female sailfin molly. We scored the number of mating attempts that males directed to conspecific and heterospecific females. Males in most sympatric and allopatric populations demonstrate no clear preference for conspecifics. In addition, we found some evidence for a difference in mating preference between allopatric and sympatric populations with males from allopatry showing a greater heterospecific mate preference. These results indicate a conflict between species and mate-quality recognition. In sympatry this conflict may contribute to the persistence of gynogenetic Amazon mollies.

Female Preferences for Sailfin and Body Size in the Sailfin Molly, Poecilia latipinna

AbstractWe tested the mating preference of female sailfin mollies (Poecilia latipinna) by presenting them with pairs of dummy males differing in: (I) sailfin and body size together (holding sailfin : body size ratio constant); (II) body size alone (holding sailfin size constant); (III) sailfin size alone (holding body size constant); and (IV) sailfin : body size ratio (holding total lateral projection area constant). Females spent more time near dummies of greater sailfin or greater body size. The preference functions based on the first three sets of stimuli showed a similar pattern: the preference between any two simultaneously presented dummies increased with the magnitude of the discrepancy in lateral projection area (LPA) between them. However, when LPA was held constant in expt (IV), neither body size, sailfin size, nor any particular dummy (i.e. any particular sailfin + body size combination) was preferred. These findings suggest that increased LPA is more stimulating to sexually receptive females and that females consequently prefer larger males. The sailfin may therefore have evolved as a way for males to exploit this sensory bias and appear larger to prospective mates.

Female sailfin mollies, Poecilia latipinna, remember males and copy the choice of others after 1 day

Theoretical and experimental evidence indicates that females copy the mate choice of other females under certain conditions. In all mate choice copying experiments with fish to date, females were allowed to copy the choice of a model female immediately after the focal female had observed a model female interacting with a male. It is not known whether females continue to copy the choice of the model female after a longer interval. We investigated whether sailfin molly females also copy the choice of other females when they are prevented from copying immediately after observing a model female next to a previously nonpreferred male. We performed three copying experiments in which females could copy the choice of the model female immediately after, 1h after or 1 day after observing the model female next to the previously nonpreferred male. In control experiments, we tested whether females chose consistently when they had no opportunity to copy, and whether females showed shoaling behaviour under these conditions. Females copied the choice of the model female immediately after, 1h after and even 1 day after the observation of the model female interacting with the previously nonpreferred male. Females chose consistently between males when they had no opportunity to copy, and females did not shoal under these conditions. We conclude that females remember individual males with whom a model female had interacted, even after 1 day. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.

The role of information in mate-choice copying in female sailfin mollies ( Poecilia latipinna )

Female mate choice is a complex process involving both genetic and social factors. Extrinsic cues may play a role in determining how these factors interact. Mate-choice copying is a socially influenced mate-choice strategy in which females observe other females during mate choice and choose the same male as those females. Previous studies have shown that female sailfin mollies (Poecilia latipinna) prefer larger over smaller males, and this preference is assumed to be genetically based. In this study we tested, first, whether sailfin molly females changed their mate preference in favour of smaller males when they could obtain more information by observing two model females sequentially for 5 min each or one model female for 20 min next to the smaller male. Second, we tested if females that had changed their preferences in favour of smaller males maintained this learned preference afterwards. In copying experiments, females changed their preferences in favour of smaller males both when they could observe two model females each for 5 min near by a smaller male and when they could observe one model female for 20 min near the smaller male. In the latter case, females maintained this learned preference for smaller males up to 5 weeks after the copying experiment. This shows that mate-choice copying has a long-lasting effect on mate-choice decisions in sailfin molly females and that mate-choice copying can serve as a mechanism for cultural inheritance of mate preferences in females.

Geographical variation in reproductive character displacement in mate choice by male sailfin mollies.

Female Amazon mollies, Poecilia formosa, are a unisexual species that reproduce by gynogenesis. They must coexist and mate with males of other species (usually the mollies Poecilia latipinna or Poecilia mexicana) to induce embryogenesis, but inheritance is strictly maternal. We examined the mating preference of the male sailfin molly, P. latipinna, for female sailfin mollies versus Amazon mollies, P. formosa. We compared the mating preferences of sympatric and allopatric populations collected throughout the Gulf Coast of North America. Male P. latipinna from six populations sympatric with Amazon mollies showed a significantly greater strength of preference for conspecific sailfin females than males from five populations that were allopatric with Amazon mollies. These results provide strong evidence for reproductive character displacement of male mate choice in sympatry. Furthermore, the large geographical range of populations that we tested revealed variation among populations within sympatry and allopatry, indicating that it is important to evaluate a large number of populations when examining reproductive character displacement.

SEXUAL HARASSMENT AS A COST FOR MOLLY FEMALES: BIGGER MALES COST LESS

AbstractFemales of many species receive male attention that reflects a conflict between the sexes over reproduction. Here we demonstrate that female sailfin mollies (Poecilia latipinna) suffer such a cost via a reduction of their feeding time in the presence of males. Female sailfin mollies spend significantly more time feeding when accompanied by an Amazon molly (P.formosa) or a sailfin molly female than when accompanied by a male sailfin molly. Furthermore, we show that male sexual harassment is size dependent and that small males impose a greater cost on females.