Prior exposure to male phenotypes influences mate choice in the guppy, Poecilia reticulata

This study examined the effect of experience on the patternof mate choice in female guppies. Females from some naturalpopulations are known to discriminate among males on the basisof the relative area of orange in the color pattern. We exposedmaturing female guppies to groups of males that differed inphenotvpic distribution of orange coloration (high orange, loworange, and mixed) and tested their subsequent mating preferences.Females that had been exposed to high-orange or low-orange malegroups showed no discrimination in choice tests, but femalesexposed to mixed male groups favored high-orange males overlow-orange males. These results demonstrate that mating preferencesof females can be modified depending on prior experience. Femalesmay be able to adjust their pattern of mate choice dependingon the degree to which choice cues permit effective discriminationamong males. This potential for short-term modification of matechoice patterns could affect the evolutionary outcome of sexualselection     

Sex differences in dogfish behaviour: alternative activity patterns and habitat choice

Guppies are highly sexually dimorphic and females have been shown to mate preferentially with males with various visible traits. Guppies, however, have been shown to respond behaviourally to odour cues from conspecifics. Using a specially designed olfactory choice tank, we tested whether females (1) could detect other guppies on the basis of their olfactory cues alone, (2) preferred to associate with males or with females and (3) could distinguish between different males. Female guppies were found to associate preferentially with other guppies when given a choice between water containing cues from another fish and water containing no cues. When females were presented with olfactory cues from a male or a female, they preferred the female initially but most then reversed their decision and swam to the male. Females associated preferentially with certain males based upon olfactory cues alone. Males, however, preferred on the basis of olfactory cues were the least preferred for visual cues.     

Female preferences based on olfactory cues in the guppy (Poecilia reticulata)

Guppies are highly sexually dimorphic and females have been shown to mate preferentially with males with various visible traits. Guppies, however, have been shown to respond behaviourally to odour cues from conspecifics. Using a specially designed olfactory choice tank, we tested whether females (1) could detect other guppies on the basis of their olfactory cues alone, (2) preferred to associate with males or with females and (3) could distinguish between different males. Female guppies were found to associate preferentially with other guppies when given a choice between water containing cues from another fish and water containing no cues. When females were presented with olfactory cues from a male or a female, they preferred the female initially but most then reversed their decision and swam to the male. Females associated preferentially with certain males based upon olfactory cues alone. Males, however, preferred on the basis of olfactory cues were the least preferred for visual cues.     

Influence of male nuptial plumage on mate selection in the female mallard (Anas platyrhynchos)

The aim of this study was to investigate the basis of mate selection in the mallard, with special reference to the role of the female. Females were reared under more or less restricted social conditions during ontogeny. When sexual mature they were offered a choice between males of different colour categories. The females used were raised under three conditions: (1) with natural mother and siblings (control females), (2) with experience of other conspecific females but no males, or (3) with no experience of ducks at all (Kaspar Hauser). The total number of females used was 227. The females were able to discriminate between normal mallards and differently coloured mallards to a large extent irrespective of their own early experience. This suggests that the females' initial mate selection is dependent on male plumage characteristics.     

Age and experience affect female choice in the guppy (Poecilia reticulata)

Female choices of males, and how these choices are influenced by ecological and social factors, have been studied extensively. However, little is known about the effects of age and breeding experience on female mating decisions. We used video techniques to examine female mate choice in guppies based on the area of carotenoid (orange) pigmentation on the body. Females were presented with paired images of males, one ornamented and the other plain. Visual preference for each male was measured. Age-related changes in the criteria of choice were examined by comparing the responses of the same mature but sexually inexperienced 6-mo-old and 12-mo-old females. Effects of breeding experience on female choice were examined by comparing mate preferences of 12-mo-old female virgins with their preferences after they had mated and produced a brood. Female preferences for ornamented males with large areas of carotenoid pigment changed with age but not with mating experience. Six-month-old virgin females preferred ornamented males, whereas 12-mo-old virgin and postpartum females did not differentiate between males based on orange coloration. The results are discussed in light of life-history theory and have important implications for studies of sexual selection as well as for the design of mate-choice studies.     

Sexual selection is influenced by both developmental and adult environments

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.     

Mate choice in the monogamous and polychromatic Midas cichlid, Cichlasoma citrinellum

Choice of mate in the Midas cichlid, Cichlasoma citrinellum (Günther, 1864), has been examined from a number of perspectives, proceeding from general species attributes to individual differences.
The Midas cichlid discriminates against closely-related, highly-similar Cichlasoma , and recognizes sex, probably chemically in both cases. It is polychromatic and changes from the normal (N) pattern to gold (G) or even white at almost any age. Gold colouration inhibited attack and made it difficult to mate an N female with a G male; the inhibiting effect was cancelled by using a larger N female.
Because the Midas cichlid is also biparentally monogamous, early experience could easily influence later choice of mate. G females of G × G parents preferentially spawned adjacent to G males; N females of N × N spawned mainly before N males. N females of G × G pairs, however, showed no preference.
Groups of females were reared by all four combinations of two colours and two sexes, or by no parents. Females reared by identically pure-coloured parents responded most to males of those colours, whereas females raised by mixed-colour parents did not discriminate. Females reared without parents preferred N males. Regardless of their own or their parents' colour, juveniles spent more time with N juveniles and behaved less aggressively towards them, compared to G juveniles.
Fish were offered a choice among potential mates that differed in aggressiveness, size or breeding experience. Males did not choose on the basis of those traits. Females preferred large, aggressive, experienced males. Pairs with large aggressive males more readily kept a breeding territory, and aggressive experienced males guarded young more effectively. All females were equally aggressive in protecting their young.     

Sex-Specific Audience Effect in the Context of Mate Choice in Zebra Finches

Animals observing conspecifics during mate choice can gain additional information about potential mates. However, the presence of an observer, if detected by the observed individuals, can influence the nature of the behavior of the observed individuals, called audience effect. In zebra finches (Taeniopygia guttata castanotis), domesticated males show an audience effect during mate choice. However, whether male and female descendants of the wild form show an audience effect during mate choice is unknown. Therefore, we conducted an experiment where male and female focal birds could choose between two distinctive phenotypes of the opposite sex, an artificially adorned stimulus bird with a red feather on the forehead and an unadorned stimulus bird, two times consecutively, once without an audience and once with an audience bird (same sex as test bird). Males showed an audience effect when an audience male was present and spent more time with adorned and less time with unadorned females compared to when there was no audience present. The change in time spent with the respective stimulus females was positively correlated with the time that the audience male spent in front of its cage close to the focal male. Females showed no change in mate choice when an audience female was present, but their motivation to associate with both stimulus males decreased. In a control for mate-choice consistency there was no audience in either test. Here, both focal females and focal males chose consistently without a change in choosing motivation. Our results showed that there is an audience effect on mate choice in zebra finches and that the response to a same-sex audience was sex-specific.     

Independent Mating Preferences for Male Body Size and Coloration in Female Trinidadian Guppies

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.     

Effects of Hunger on Mate-choice Copying in the Guppy

One potential opportunity cost associated with direct assessment of males by females is lost foraging time. It has been hypothesized previously that females may reduce their mate-assessment time by copying the known mate choice of other females. If mate copying reduces mate-assessment time, then females that engage in copying behaviour should have more time available for foraging. In this study, we experimentally investigated the effects of hunger, and thus the immediate need for energy, on the tendency of female guppies, Poecilia reticulata, to copy the mate choice of others. We manipulated the hunger level of individual females in four different treatments by either depriving them of any food or giving them unlimited access to food for 24 h or 48 h prior to testing their mating preference. Each female was then allowed to choose between two stimulus males, matched for size and colour, after having viewed another female (the model) apparently choose one of the males as a mate. We predicted that hungry female guppies should be more likely to engage in mate-choice copying than more recently fed females, when given the opportunity. Contrary to our a priori prediction, only the most well-fed females (with prior access to feed for 48 h) copied the mate choice of the model female significantly more often than expected by chance. Females in each of the other three treatments chose randomly between the two stimulus males presented.     

Fitness effects of female mate choice: preferred males are detrimental for Drosophila melanogaster females

The evolution of female mate choice, broadly defined to include any female behaviour or morphology which biases matings towards certain male phenotypes, is traditionally thought to result from direct or indirect benefits which females acquire when mating with preferred males. In contrast, new models have shown that female mate choice can be generated by sexual conflict, where preferred males may cause a fitness depression in females. Several studies have shown that female Drosophila melanogaster bias matings towards large males. Here, we use male size as a proxy for male attractiveness and test how female fitness is affected by reproducing with large or small males, under two different male densities. Females housed with large males had reduced lifespan and aged at an accelerated rate compared with females housed with small males, and increased male density depressed female fitness further. These fitness differences were due to effects on several different fitness components. Female fitness covaried negatively with male courtship rate, which suggests a cost of courtship. Mating rate increased with male size, whereas female fitness peaked at an intermediate mating rate. Our results suggest that female mate choice in D. melanogaster is, at least in part, a by-product of sexual conflict over the mating rate.     

The Allure of the Distinctive: Reduced Sexual Responsiveness of Female Guppies to 'Redundant' Male Colour Patterns

Frequency-dependent mating behaviour has the potential to maintain genetic variation in characteristics of organisms. The colour patterns of guppies ( Poecilia reticulata ) provide an example of one of the most extreme genetically based polymorphisms known in nature, for which frequency-dependent mate choice could be a mechanism. Numerous studies have shown that female guppies base mating preferences on male colour patterns and there is evidence that females prefer to mate with males displaying novel or unfamiliar colour patterns. This preference could lead to frequency-dependent mating success in males. Nevertheless, the possibility that female sexual responsiveness itself may depend on the frequency of male types has not been tested systematically in guppies or any other species. This study examined the sexual responses of female guppies in experimental groups consisting of two males with similar (redundant) and two males with different (unique) colour patterns. We found that female guppies were much more likely to respond sexually to the displays of unique males than to those of redundant males. Further, there was no effect of orange colouration on female responsiveness as has been documented for this population in several previous studies, thus, discrimination against redundant male types appears to have overridden directional selection based on colour pattern characteristics. This discrimination against redundant male types could in turn lead to frequency-dependent mating success in males and maintenance of colour pattern polymorphism.     

Female choice and the relatedness of mates in the guppy (<Emphasis Type="Italic">Poecilia reticulata</Emphasis>)

Several studies suggest that females may offset the costs of genetic incompatibility by exercising pre-copulatory or post-copulatory mate choice to bias paternity toward more compatible males. One source of genetic incompatibility is the degree of relatedness among mates; unrelated males are expected to be genetically more compatible with a female than her relatives. To address this idea, we investigated the potential for inbreeding depression and paternity biasing mechanisms (pre- and post-copulatory) of inbreeding avoidance in the guppy, Poecilia reticulata. Inbreeding resulted in a reduction in offspring number and quality. Females mated to siblings gave birth to significantly fewer offspring compared to females mated to non-siblings and inbred male offspring took longer to reach sexual maturity. There was no evidence of inbreeding avoidance in pre-copulatory behaviors of females or males. Sexual responsiveness of females to courting males and the number of sexual behaviors males directed at females did not decrease as a function of the relatedness of the two individuals. We also tested whether female guppies can use post-copulatory mechanisms to bias sperm usage toward unrelated males by comparing the number of offspring produced by females mated to two of their siblings (SS), two males unrelated to the female (NN), or to one unrelated male and a sibling male (NS). We found that NS females produced a number of offspring not significantly different than what would be expected if fertilization success were halfway between completely outbreeding (NN) and completely inbreeding (SS) females. This suggests that there is no significant improvement in the number of offspring produced by females mating to both related and unrelated males, relative to that which would be expected if sperm from both males were used equally. Our results suggest that female guppies do not discriminate against closely related males or their sperm.     

The relative importance of orange spot coloration and total length of males in female guppy mate preference

Female mate choice by multiple male traits is an important current topic in animal behavior. However, the relative importance among the multiple cues in female choice is not explored in most cases. Female guppies Poecilia reticulata use both the color saturation of orange spots and the total length of males as mate choice criteria. In the present study, we used digitally modified video playbacks to examine the relative importance of these two male traits to female mate preferences. We initially examined the effective difference in the color saturation of orange spots as well as that in total length between two stimulus male images. Females only showed a strong preference for a bright male image (compared to the dull image) when the difference in color saturation was large (91% versus 25%). Conversely, females only exhibited a preference for larger size when they were presented a choice between two relatively small male images (total length 26.0 mm versus 23.0 mm). When two male images in which both the two traits were modified were presented to females, they prioritized male images possessing higher color saturation of orange spots, indicating the color saturation of male orange spots to be a more important factor than the total length in their mate choice. The color saturation of orange spots may convey more reliable information about the males to the females than their total lengths. These findings imply that females may rank multiple male criteria depending on relative benefits or costs derived from their mate choice based on each criterion.     

Mate-choice copying under predation risk in the Trinigadian guppy (Poecilia reticulata)

Although females of numerous species possess genetically-basedpreferences for certain male trails and male preferentiallywith males possessing these traits, recent theoretical and experimentalevidence indicates that they may also copy (imitate) the matechoices of other females under certain circumstances. Such mate-choicecopying is expected to be most prevalent when females have theopportunity to observe the mate choices of others and when matechoice is costly to females. One potential direct fitness costof mate choice is increased individual risk of mortality dueto predation. Here, we investigate for the first time the effectof increasing the apparent risk of predation on the tendencyof females to copy the experimentally staged mate choice ofanother female. Using adult female guppies (Poecilia reticulata)originating from a Trinidadian population that experiences arelatively high fish predation pressure, we first establishthat they possess a preference for the more brighdy coloredof two simultaneously presented males in the absence of bothmate-copying opportunity and an immediate threat of predation.However, most females reversed their initial mate preferencewhen given an opportunity to copy the mate preference of anotherfemale in the absence of predation threat The proportion offemales reversing their preference when given the opportunityto do so was not affected by increasing the apparent risk of(fish) predation. This result may be owing either to femaleguppies tending to copy the mate choice of others whenever theopportunity arises because the benefits of doing so accrue irrespectiveof the ambient risk of predation or to females choosing randomlybetween males with respect to their color pattern in the presenceof the predator irrespective of mate-copying opportunity. Thesetwo explanations for the apparent lack of an effect of predationrisk on mate-choice copying per se are both plausible but unfortunatelycould not be easily distinguished here. It may thus be possible,and interesting, that individual female guppies chose randomlybetween the available males in the presence of the predatorbut otherwise copied the choice of others when given the opportunityto do so.     

Dangerous love? Predation risk does not affect female mate choice in blue‐black grassquits

Predation risk may be an important factor affecting female mate choice. Hypothetically, females could choose extravagantly ornamented males that survive in high predation risk environments. However, this decision could be different if choosing a conspicuous male under high predation risk is costly for females or results in reduced offspring survival. In such contexts, females could become indifferent to male quality or prefer inconspicuous males. We tested this idea using captive blue‐black grassquits (Volatinia jacarina, Linnaeus, 1766), a species in which males perform conspicuous leap displays coupled with songs during the breeding season, which presumably subjects females and offspring to higher predation risk. Females were placed in an arena with speakers on opposite sides emitting male courtship songs. One speaker emitted songs at a high rate (proxy for a conspicuous male) while the other speaker broadcast songs at a low rate (proxy for a less conspicuous male). While the female evaluated the two male songs, a third speaker emitted vocalizations characterizing three levels of risk: adult predator, nest predator, and no‐risk control. Females showed no preference for either male stimuli across the predation risk treatments. This lack of preference relative to frequency of male vocal displays suggests that leap‐song frequency is not used by females during mate choice. We suggest that in addition to its role in courtship, male grassquit displays also signal status to other males when competing for territories. Thus, we propose that predation risk does not directly influence blue‐black grassquit intersexual selection and that females in this species may exercise indirect mate choice, choosing social mates based on male ability to establish and defend a territory, and relying secondarily upon other aspects of male display attributes, such as its visual components.     

Premating Avoidance of Inbreeding Absent in Female Guppies (Poecilia reticulata)

The recognition and avoidance of kin during mating can be an important means of reducing the potential for inbreeding depression in offspring. We report here that premating mechanisms to avoid inbreeding, either innate or learnt through juvenile experience, are at best weak in female guppies (Poecilia reticulata). Guppies are small, ovoviviparous, neo‐tropical freshwater fish, with a polygamous mating system where males actively court females and females are selective of their mates. In a series of mate‐choice experiments, naïve, virgin females of the Quare River population in Trinidad were given a choice between a brother and a non‐sib male from the same population. Initially, females were only provided olfactory cues upon which to base their choice and then subsequently both olfactory and visual cues. Despite the females displaying mate choice, we found no evidence of them discriminating between the male types in either experiment. There was thus no indication of inbreeding avoidance, suggesting that experiences after maturation or with mature males (e.g. rare male preference), dispersal and/or post‐mating mechanisms may be evolutionarily more important avoidance mechanisms.     

Female Size Influences Mate Preferences of Male Guppies

Guppies (Poecilia reticulata) have a promiscuous mating system in which female choice for brightly coloured males plays an important role. Consequently, much research on guppies has examined how mate choice by females has lead to the evolution of male colour patterns. Much less attention has been devoted to mate choice by males in this species. In this study, we show that male guppies are choosy when selecting a female to associate with, significantly preferring the larger female when presented with two females that differed by ≥2 mm in standard length (SL). The strength of their preference for each female increased with absolute female size. The relative sizes of the females, however, also influenced male mating preferences: males showed stronger preferences for the larger female as the difference in SL between the two females increased. Such a preference for larger females is not unexpected as fecundity generally increases with body size in female fish. Thus, males choosing to mate with the larger female should have higher reproductive success. An apparent, but non‐significant anomaly, whereby males appear to prefer the smaller of the two females when the difference between female SL was <4 mm, deserves further investigation.     

Do Female Western Mosquitofish,Gambusia affinis,Prefer Ornaments That Males Lack?

Some species in the family Poeciliidae are known for extravagant male ornaments and courtship behavior (e.g., guppies), but the majority of poeciliids are characterized by coercive male copulation attempts that seem to circumvent female choice. In some lineages with male ornaments, female sensory bias may have preceded the evolution of corresponding male signals. We examined female preferences for colorful ornaments in Western mosquitofish, Gambusia affinis, in which males lack ornamentation and reproduce primarily through coercive mating attempts. We found that females exhibited a positional affinity for males that were artificially ornamented with blue coloration over males that had been treated with a transparent ornament. Females exhibited the opposite effect for males treated with red ornaments. In contrast, focal females did not exhibit behavioral discrimination between two live stimulus females or two models (silver fishing lures) with blue vs. transparent ornaments. This suggests a sexual context for female discrimination between males based on ornament color and whether an ornament was present. Because tribe Gambusiini is the basal branch of family Poeciliidae, the results of this study are consistent with the hypothesis that female responsiveness to male coloration is the ancestral poeciliid character state.     

斜纹夜蛾的性选择行为

【目的】为了解斜纹夜蛾Spodoptera litura Fabricius体重、日龄、交配经历及形态特征对其性选择行为的影响。【方法】本实验通过标记成虫后,采用观察记录的方法对其进行探究。【结果】斜纹夜蛾雌虫的体重对雄虫的性选择影响比较明显,体重较大雄虫优先选择体重较小的雌虫(71.43%),而体重较小雄虫喜欢选择体重较大的雌虫(72.00%)。体重较大和体重较小的雄虫都能获得体重较大雌虫的交配选择,但是体重较大者被选择的机会更大(70.00%),体重较小的雄虫不能获得体重较小雌虫的选择。雄虫仅选择1日龄的雌虫,而雌虫偏向选择3日龄和5日龄雄虫。交配经历影响斜纹夜蛾的性选择,未交配的雄虫优先选择未交配的雌虫(86.67%),但未交配的雌虫则优先选择已交配的雄虫(66.67%)。雄虫的形态特征(体长、翅展、腹长、复眼间距和触角长)对雌虫性选择有较明显的影响,但雌虫的形态特征除翅展的大小外,其体长、腹长、复眼间距和触角长等形态特征在雄虫选择进行交配中的作用不大。【结论】体重、日龄、交配经历及形态特征都能不同程度影响斜纹夜蛾的性选择行为。