Repeatable female preferences, mating order and mating success in the poeciliid fish, Heterandria formosa

Sexual selection via female choice can afford preferred males comparably higher mating success than those males that lack preferred traits. In addition, many models of sexual selection assume that both male traits and female preferences are heritable. In this study we test whether females of the poeciliid fish, Heterandria formosa, have repeatable pre-copulatory preferences for larger males. We also test whether female pre-copulatory preferences are always reliable indicators of male mating success. When given a choice between a large and a small male, females prefer larger males, and the repeatability of this preference is high. Although there are no overall differences in male mating success between large and small males, large males have a higher mating success when they are the first to mate than when they are the second to mate. Likewise, preferred males also have higher mating success when they are the first to mate than when they mate second. Therefore, the repeatable female preferences observed in this study only predict male mating success when the preferred male mates first. These results illustrate that even significantly repeatable female preferences do not translate into male mating success, which is an assumption of many examinations of the importance of female choice in sexual selection.     

Selection for male choice based primarily on mate compatibility in the oldfield mouse, Peromyscus polionotus rhoadsi

Despite the consensus that mate choice acts as a mechanism for selection of secondary sexual traits, the evolutionary forces affecting mate preferences themselves remain controversial. In this study, we first demonstrated selection acting directly on the mate preferences of monogamous male oldfield mice, Peromyscus polionotus rhoadsi. One group of male oldfield mice were allowed to express a social preference between two potential mates, and were subsequently paired with either their preferred or rejected female. Among these pairs, those containing preferred females produced more offspring than did those containing rejected females. We next demonstrated that this fitness advantage depended primarily on compatibility between the members of a mated pair. A second group of male oldfield mice were not allowed the opportunity to express a social preference between potential mates. Rather, these males were paired with females that had been either preferred or rejected by males in the first group. Among these pairs, those containing preferred females did not produce more offspring than those containing rejected females. In other words, individual mate preferences had fitness consequences only for those males that expressed them, demonstrating that these preferences were based primarily on compatibility between mates.     

Do female association preferences predict the likelihood of reproduction?

Sexual selection acting on male traits through female mate choice is commonly inferred from female association preferences in dichotomous mate choice experiments. However, there are surprisingly few empirical demonstrations that such association preferences predict the likelihood of females reproducing with a particular male. This information is essential to confirm association preferences as good predictors of mate choice. We used green swordtails (Xiphophorus helleri) to test whether association preferences predict the likelihood of a female reproducing with a male. Females were tested for a preference for long- or short-sworded males in a standard dichotomous choice experiment and then allowed free access to either their preferred or non-preferred male. If females subsequently failed to produce fry, they were provided a second unfamiliar male with similar sword length to the first male. Females were more likely to reproduce with preferred than non-preferred males, but for those that reproduced, neither the status (preferred/non-preferred) nor the sword length (long/short) of the male had an effect on brood size or relative investment in growth by the female. There was no overall preference based on sword length in this study, but male sword length did affect likelihood of reproduction, with females more likely to reproduce with long- than short-sworded males (independent of preference for such males in earlier choice tests). These results suggest that female association preferences are good indicators of female mate choice but that ornament characteristics of the male are also important.     

Olfactory cues,genetic relatedness and female mate choice in the agile antechinus (<Emphasis Type="Italic">Antechinus agilis</Emphasis>)

Females show mate preferences for males that are genetically dissimilar to themselves in a variety of taxa, but how females choose these males is not clearly understood. In this study, we examined the effects of olfactory stimuli and genetic relatedness on female mate choice in a small carnivorous marsupial, the agile antechinus (Antechinus agilis), during two breeding seasons. Captive female antechinus in oestrus were provided with a combination of male urine and body scent from two novel males, one more genetically similar and one more dissimilar to the females, in a Y-maze olfactometer. Genetic relatedness between females and pairs of males was determined using highly polymorphic, species-specific, microsatellite markers. Females consistently chose to visit the scents of males that were genetically dissimilar to themselves first, spent significantly more time near the source of those scents and showed more sexual and non-exploratory behaviours near those scents. These data demonstrate that chemosensory cues are important in mate choice in the agile antechinus and that females prefer males that are genetically dissimilar to themselves.     

Display rate by male fairy-wrens (Malurus cyaneus) during the fertile period of females has little influence on extra-pair mate choice

Empirical and theoretical studies have only recently begun to examine how females use complex multi-component displays when selecting mates. Superb fairy-wrens are well suited to the study of female choice because females have control over extra-group paternity and cuckold their mates at high rates, while males possess a variety of sexually selected traits. Available evidence suggests that females base their extra-group mate choice on the timing of male moult into breeding plumage or the onset of display. However, males continue to perform elaborate displays throughout the season, and direct most displays to females during their fertile period. We therefore conducted focal observations on fertile females to quantify the frequency of male display and used microsatellite genotyping to compare the role of display rate during the breeding season and the timing of male moult on female mate choice. We show that the addition of data on male display rate does not improve our ability to predict which males obtain extra-group paternity. The timing of male moult into breeding plumage remains the only predictor of male extra-group reproductive success. Nevertheless, we found that males displayed more to females that were unable to select extra-group mates on the basis of the timing of moult or the onset of display. This raises the possibility that there are circumstances when females use display rate to discriminate between potential extra-group sires. Overall this study supports the theoretical prediction that females are more likely to base their mate choice on reliable indicators of male quality such as fixed morphological traits and displays of endurance, in this case an early moult into breeding plumage and the performance of an elaborate display during the winter, than a flexible behavioural trait such as display rate during the breeding season. Received: 26 January 2000 / Revised: 1 August 2000 / Accepted: 26 August 2000     

Effects of testosterone supplementation on chemical signals of male Iberian wall lizards: consequences for female mate choice

In some lizards, female mate choice is influenced by chemicals secreted by males, e.g., via the femoral glands. Secretions of the femoral glands are under direct androgenic control and vary seasonally with androgen production. However, whether increased testosterone (T) levels affect the concentration and chemical composition of secretions or their attractiveness to females is unknown. We manipulated T levels of male Iberian wall lizards, Podarcis hispanica, with silastic implants. Differential tongue-flick rates indicated that females detected and discriminated between femoral secretions of control and T-implanted males based on chemical cues alone. Females showed greater responses to secretions of T-males, which might suggest that T increased the concentration of chemical signals. Further analyses by gas chromatography–mass spectrometry indicated that T supplementation induced qualitative changes in lipid composition of femoral secretions. T-males had decreased relative proportions of cholesta-5,7-dien-3-ol in secretions, which might be related to the negative effects of T on the immune system and on lipid metabolism. However, experiments of choice of males’ scent showed that females neither preferred nor avoided the scent marks of T-males but preferred males that maintained higher proportions of cholesta-5,7-dien-3-ol in secretions, independently of the experimental manipulation. Thus, because this steroid is negatively affected by T, there might be trade-offs among increasing T levels to increase the production of chemical secretions, maintain metabolism, and attract females.     

Male preference for colourful females affected by male size in a marine fish

It is becoming increasingly clear that mate preferences are not static, but can vary as a function of ecological conditions and the state of the choosing individual. This applies not only to females, the sex that has usually been the subject in research on mate preferences, but also to males. Under certain conditions, males should be selective in their choice of breeding partner. In the two-spotted goby, Gobiusculus flavescens, a small marine fish, breeding females develop conspicuous yellow-orange bellies, which they actively display to males during courtship. We have recently shown that males prefer more colourful females as mates. In this study, we test if the size of a male affects his preference for colourful females. Using three-compartment mate-choice aquaria, we recorded the interest shown by a male in two females differing in coloration but similar in size. Large and small males were equally eager to court females, but only large males showed a greater interest in the more colourful females. We suggest that small males are unselective because they usually obtain few mating opportunities, as a result of being unsuccessful in mate attraction or male contest competition. This study provides the first demonstration that the size of a male affects his preference for female colour.     

Countermarking by male pygmy lorises (<Emphasis Type="Italic">Nycticebus pygmaeus</Emphasis>): do females use odor cues to select mates with high competitive ability?

Competitive countermarking occurs when animals compete to ensure that their scent marks are in the top-most position and more recently deposited than those of rivals. Because it takes a great deal of time and energy, and perhaps dominant or territorial status, to patrol the area and rapidly countermark rivals' marks, assessors may use the presence of countermarks as a reliable cue of the signaler's competitive ability. Selection on assessors, therefore, should favor the evolution of mechanisms to determine which scent is the countermark. Sexual selection theory predicts that females select high-quality males with whom to mate; therefore, females should mate preferentially with countermarking males. We examined the role of countermarking in intra-male competition and female mate choice in the pygmy loris. In experiment 1, we found that males deposit significantly more urine when countermarking other males' urine, but countermark female urine no more than control stimuli. In experiment 2, we exposed females to the urine of two males for several weeks. One male always deposited his urine first, whereas the second male always deposited his urine later and on top of the first male's urine. When reaching peak estrus, females were given a simultaneous choice test between the two males, and showed a significant preference for the countermarking male with regard to: (1) her location and orientation to the male, (2) her chemosensory interest in the male and his cage, and (3) her affiliative socio-sexual behaviors. These results are consistent with predictions from the competitive countermarking hypothesis, and demonstrate that chemosignals play a profound role in governing female reproductive behavior in the species.     

Female sensory bias may allow honest chemical signaling by male Iberian rock lizards

Some mate choice theories propose that only male signals that are honest and condition-dependent can be stable, while another hypothesis states that males evolve signals that exploit the sensory system of females. However, sensory traps might evolve into honest signals if they are differentially costly for males. We tested whether a pre-existing sensory bias for food chemicals explained chemosensory preferences of female Iberian rock lizards for male scents. We manipulated hunger levels of females and found that food-deprived females had increased chemosensory responses to chemical stimuli from both invertebrate prey and femoral secretions of males, but not to control water. Further tests suggested that cholesta-5,7-dien-3-ol (provitamin D₃), a lipid found in both prey and males’ scent, may be one of the chemicals eliciting these responses. Moreover, hungry females spent more time on scent marks of males that had experimentally increased cholesta-5,7-dien-3-ol than on scent marks of males alone, whereas for control females this effect was not significant. We suggest that preexisting sensory bias for essential nutrients (i.e., provitamin D) may be the origin of similar female responses to male chemicals. However, previous studies have suggested that the allocation of these chemicals to ornaments is costly and only high quality males can afford it. Therefore, preexisting sensory bias for essential nutrients may further allow the evolution and maintenance of honest sexual displays.     

Multiple mating in a lekking bird: why do peahens mate with more than one male and with the same male more than once?

Summary Approximately 50% of marked peahens (Pavo cristatus) mate more than once with lek males. Some females mate with more than one male, others copulate repeatedly with the same male. The frequency of courtship also shows marked variation. Some females repeatedly engage males in courtship interactions after they have succesfully copulated with them. The likelihood of mating with more than one male increases if a female first mates with a non-preferred (unsuccessful male). There is a non-significant tendency for females to copulate with a more successful male when remating. Peahens may mate with a non-preferred male first if they do not encounter a successful male during their initial period of choice, perhaps because the most successful male on a lek was courting another female and/or was defended by another female. There are more aggressive interactions between females in front of preferred males. Preferred males receive more repetitive courtship behaviour and repeated matings. Dominant females are more likely to engage in repetitive courtship and matings. The number of times a female initiates courtship on any one day increases with the number of other females actively courting males at a lek site on that day. We suggest that there is competition amongst females for access to preferred males and that dominant females try to monopolise these males by repeatedly engaging them in courtship interactions. We discuss the implications of these observations for the idea that female may gain directly from mate choice in a species where males contribute nothing but gametes to their offspring. Correspondence to: M. Petrie at the present address     

Role of Familiarity and Preference in Reproductive Success in Ex Situ Breeding Programs

Abstract: Success of captive‐breeding programs centers on consistent reproduction among captive animals. However, many individuals do not reproduce even when they are apparently healthy and presented with mates. Mate choice can affect multiple parameters of reproductive success, including mating success, offspring production, offspring survival, and offspring fecundity. We investigated the role of familiarity and preference on reproductive success of female Columbia Basin pygmy rabbits (Brachylagus idahoensis) as measured by litter production, litter size, average number of young that emerged from the burrow, and average number of young that survived to 1 year. We conducted these studies on pygmy rabbits at the Oregon Zoo (Portland, Oregon, U.S.A.) and Washington State University (Pullman, Washington, U.S.A.) from February to June 2006, 2007, and 2008. Before mating, we housed each female adjacent to 2 males (neighbors). Female preference for each potential mate was determined on the basis of behavioral interactions observed and measured between the rabbits. We compared reproductive success between females mated with neighbor and non‐neighbor males and between females mated with preferred and nonpreferred males. Our findings suggest that mating with a neighbor compared with a non‐neighbor and mating with a preferred neighbor compared with a nonpreferred neighbor increased reproductive success in female pygmy rabbits. Litter production, average number of young that emerged, and average number of young that survived to 1 year were higher in rabbits that were neighbors before mating than in animals who were not neighbors. Pairing rabbits with a preferred partner increased the probability of producing a litter and was significantly associated with increased litter size. In captive breeding programs, mates are traditionally selected on the basis of genetic parameters to minimize loss of genetic diversity and inbreeding coefficients. Our results suggest that integrating genetic information with social dynamics and behavioral measures of preference may increase the reproductive output of the pygmy rabbit captive‐breeding program. Our findings are consistent with the idea that allowing mate choice and familiarity increase the reproductive success of captive‐breeding programs for endangered species.     

Mate compatibility,parental allocation and fitness consequences of mate choice in the sand goby <Emphasis Type="Italic">Pomatoschistus minutus</Emphasis>

Recent theory and empirical work suggests that there may be variation among females in mate preferences that is adaptive. One of the possible mechanisms maintaining variability in preferences and preferred traits is that the benefits of mate choice may depend on compatibility with potential mating partners. We examined fitness consequences of mate choice in a species of fish, the sand goby, Pomatoschistus minutus with a special focus on mate compatibility. Females were given the opportunity to establish their mate preferences in a dichotomous mate choice experiment. This information was then applied by mating the focal or control female with either the preferred or the non-preferred male. The parental performance of the males of these four mating combinations was then measured. In a separate experiment, we assessed the female differential allocation by determining the residual gonad weight of spawned females as a measure of the proportion of eggs spawned. We also estimated the amount of filial cannibalism separately for both sexes. Our results show that preferred males provided benefits in the form of an increased number of hatching eggs. This benefit was the same when the male was mated with a focal or a control female. Hence, we found no support for benefits that depend on mate compatibility. Neither did we find support for the hypothesis that females would lay a different number of eggs depending on the male status. The results also indicate that male filial cannibalism has a strong role in determining hatching success in this species.     

Mate preferences in <Emphasis Type="Italic">Drosophila</Emphasis> infected with <Emphasis Type="Italic">Wolbachia</Emphasis>?

The maternally inherited bacterium Wolbachia pipientis generates strong reproductive incompatibilities between uninfected females and infected males (cytoplasmic incompatibility), significantly reducing both female and male reproductive success. Such fitness costs are thought to place selective pressure on hosts to evolve pre-copulatory preferences for mating with compatible mates, thereby enabling them to avoid the reproductive incompatibilities associated with Wolbachia. Therefore, uninfected females are predicted to prefer mating with uninfected males, whereas infected males are predicted to prefer mating with infected females. Despite these predictions, previous investigations of pre-copulatory mate preferences in Wolbachia-manipulated Drosophila have not found evidence of female preference for uninfected or compatible males. However, none of these studies utilised a design where focal individuals are provided with a simple choice in a relatively non-competitive situation. We examined both female and male pre-copulatory mate preference based on mate infection status in Drosophila simulans and D. melanogaster using simple choice assays involving between 30–50 replicates per treatment. Although we found no evidence of female pre-copulatory mate preferences in either species, male D. simulans exhibited some preference for mating with females of the same infection status. However, this preference was not evident when we repeated the experiment to confirm this finding. Consequently, we conclude that neither male nor female D. melanogaster and D. simulans exhibit significant Wolbachia-associated pre-copulatory mate preferences.     

The scent of sun worship: basking experience alters scent mark composition in male lizards

Signals used in female choice should honestly advertise the benefits that males can provide, with direct benefits often argued as being more important than indirect benefits. However, the nature of direct benefits in species without paternal care or nuptial gifts is poorly understood. Previous studies on lizards suggest that females decide where to settle and assumedly who to mate with based on information contained in scent marks from territorial males. Access to high-quality thermal resources is crucial for female reproductive success. Females may therefore be able to detect and exploit thermal-induced variation in the chemical composition of male scent marks when assessing the quality of his territory. We show that the amount of time male wall lizards (Podarcis muralis) are allowed to bask significantly alters the chemical composition of their femoral secretions used in scent marking. The direction of the change is consistent with adaptive plasticity to maintain signalling efficacy under warm conditions that increase evaporation of femoral secretions. The compounds affected by basking experience included those previously associated with male quality or shown to mediate male–male competition in lizards. However, whilst female lizards could discriminate between scent marks of males that had experienced different basking conditions, they did not preferentially associate with the scent from males from high-quality thermal conditions. These results highlight the potential importance of a previously neglected environmental effect on chemical signalling. We suggest thermal effects may have significant consequences for scent-mark composition in variable environments, with potential repercussions on olfactory communication in lizards.     

The efficacy of female choice in chimpanzees of the Taï Forest, Côte d’Ivoire

Male–male competition has historically been considered the major force driving sexual selection. However, female choice and inter-sexual conflict are increasingly recognized as important influences affecting differential mating and reproductive success. Many females exhibit preferences for particular males; however, male strategies may conflict with females’ ability to obtain their mate preferences. To influence paternity, females must affect both (1) whether or not sexual interactions occur, particularly during the periovulatory period (POP) and (2) the outcome of sexual interactions. This study focuses on the effectiveness of female choice in wild chimpanzees (Pan troglodytes verus). Over 2,600 h of data were collected on two habituated chimpanzee communities in the Taï National Park, Côte d’Ivoire. Female mate preferences were measured by quantifying proceptive and resistance behavior toward males in both the periovulatory period and non-POP phases of estrus. The efficacy of female preference was measured both (1) by measuring success rates of female proceptivity and resistance behaviors and (2) by determining how well measures of female mate preference (proceptivity and resistance rates) predict male mating success. Though male chimpanzees are clearly dominant to females, the results indicate that females could effectively resist male solicitations and, in most cases, unwanted copulations were averted. Both female proceptivity and resistance rates correlate (positively and inversely, respectively) with male mating success in POP. Outside POP, female proceptivity rates corresponded with male mating success, but resistance rates did not. Males (irrespective of rank) that were preferred by females obtained higher mating success compared to other males during the POP, suggesting that females were effective in their mate choice and that, despite clear male dominance, female choice influences paternity in wild chimpanzees.     

The effects of mating system on male mate choice in a coral reef fish

Summary We show how mate limitation appears to be critical in determining whether or not males exercise mate choice among available females. Thalassoma bifasciatum is a Caribbean reef fish with two distinct mating patterns: group-spawning and pair-spawning. In both mating systems, female fecundity is variable and size dependent, and female availability is high. However, sperm competition among group-spawning males apparently limits the number of effective matings in which a male may engage, whereas territorial pair-spawning males have little or no such limitation. Group-spawning males should be discriminating in their choice of mates and our data confirm this: there is strong evidence for assortative mating in group-spawns, with more large males joining in mating groups around large females. In contrast, pair-spawning males show no indication of mate preferences, and spawn with all females who arrive at their territories.     

The influence of potential reproductive rate and variation in mate quality on male and female choosiness in the sand goby, Pomatoschistus minutus

Recent models of choosiness in mate choice have identified two particularly important factors: the potential reproductive rate (PRR) of the choosing sex relative to that of the chosen sex, and the variation in quality of potential mates. This experimental study tested how these factors affected choosiness in male and female sand gobies, Pomatoschistus minutus. We manipulated relative PRR by means of water temperature, and mate quality by means of body length. The choosing male or female was offered a choice between two mates with either a small or a large difference in body length representing a small or a large variation in mate quality. Choosiness was measured as (1) preference for the larger mate, and (2) as whether or not spawning occurred with the smaller mate, while the larger mate was visible but screened off. We found that females preferred large males, and that their level of choosiness was affected by variation in male quality, but not by their own relative PRR. Males, on the other hand, seemed unselective in all treatments and were in general more likely than females to spawn with their provided partner. This suggests that in the sand goby, variation in male mate quality has a greater influence than relative PRR on facultative changes in female choosiness. However, a general difference in PRR between males and females may be one important factor explaining the observed sex difference in choosiness. Received: 17 April 2000 / Revised: 24 June 2000 / Accepted: 17 July 2000     

Male mate choice favors more colorful females in the gift-giving cabbage butterfly

While the phenomenon of male mate choice has attracted considerable attention in the last two decades, whether this sexual selection mechanism could drive the evolution of female ornaments remains poorly understood. Here, we used experimental manipulation of female wing coloration to investigate male mate choice in Pieris rapae, a gift-giving butterfly. Further, we tested whether males’ nutritional status influenced their mating preferences by subjecting larvae to short periods of starvation. We found that males showed significantly more mating approaches toward control females with more colorful wings (higher pteridine content), and that this preference was strongest in low-nutrition males. Additionally, a study of field-collected females revealed that pteridine-based wing coloration was positively correlated with female egg load, which suggests such ornaments may signal female quality. Pteridine-based ornaments are widespread in nature, however their potential as honest signals in male mate choice remains largely unexplored. This work furthers our understanding of how male mate choice and female ornamentation may evolve in species whose mating systems include nutritional nuptial gifts.     

Mate choice in the brown thornbill (<Emphasis Type="Italic">Acanthiza pusilla</Emphasis>): are settlement decisions,divorce and extrapair mating complementary strategies?

In socially monogamous birds, females may express mate preferences when they first select a breeding partner, through divorce and subsequent breeding dispersal to a new partner and through extrapair mating. We examined settlement patterns, divorce and breeding dispersal in a sedentary Australian passerine, the brown thornbill (Acanthiza pusilla), in relation to two traits known to influence extrapair paternity (male age and male size). Settlement decisions, divorce and territory switching behaviour were all female strategies that reduced their likelihood of breeding with 1-year-old males. Females preferred to settle in territories with 2+ -year-old males, were more likely to divorce 1-year-old males, and only switched territories if they had an opportunity to form a new pair bond with an old male. In contrast, female settlement and divorce decisions were not influenced by male size. Female thornbills obtain a direct benefit from preferring older males as social mates because breeding success improves with male age in brown thornbills. Nevertheless, divorce rates in this species were low (14% of pair bonds were terminated by divorce), and individuals rarely switched territories following the death of a mate. Both of these mating strategies appeared to be primarily constrained by the distance adults moved to initiate a new pair bond (1–2 territories) and by the limited availability of unpaired older males in the immediate neighbourhood.Communicated by M. Webster     

Audience effect alters male but not female mating preferences

Males often face strong mating competition by neighboring males in their social environment. A recent study by Plath et al. (Anim Behav 75:21–29, 2008a) has demonstrated that the visual presence of a male competitor (i.e., an audience male) affects the expression of male mating preferences in a poeciliid fish (Poecilia mexicana) with a weaker expression of mating preferences when an audience male observed the focal male. This may be a tactic to reduce sperm competition, since surrounding males likely share intrinsic preferences for female traits or copy mate choice decisions. Here, we examined the hypothesis that a same-sex audience would affect female mate preferences less than male mating preferences. Our hypothesis was based on the assumptions that (1) competition for mates in a fashion that would be comparable in strength to sperm competition or overt male–male aggression is absent among Poecilia females, and (2) P. mexicana females typically form female-biased shoals, such that almost any female mate choice in nature occurs in front of a female audience. Poecilia females (P. mexicana, surface and cave form, and the closely related gynogenetic Poecilia formosa) were given a choice between a large and a small male, and the tests were repeated while a conspecific, a heterospecific, or no audience female (control) was presented. Females spent more time in the neutral zone and, thus, less time near the males during the second part of a trial when an audience was presented, but—consistent with predictions—females showed only slightly weaker expression of mate preferences during the second part of the tests. This decline was not specific to the treatment involving an audience and was significantly weaker than the effect seen in the male sex.