Search

Juvenile diet can profoundly affect subsequent adult development, morphology and reproductive investment. Yet, little is known about how juvenile diet affects adult investment into chemical‐based sexual signalling, perhaps due to the historical assumption that pheromone production is not costly. We explored how juvenile diet influenced the reproductive investment of adults in the gumleaf skeletonizer moth, Uraba lugens. Juveniles were reared on different host plant species (Eucalyptus camaldulensis and Eucalyptus moorei) and on E. moorei host plants with different fertilizer treatments (fertilized and non‐fertilized). These juvenile diets differ in foliage carbon and nitrogen content. Several adult life history traits were influenced by juvenile diet, including body size in females, and longevity in males. However, we found no evidence from Y‐maze olfactometer assays that diet affected the attractiveness of female pheromones to males. Finally, host plant species affected male pre‐copulatory investment: males reared on E. moorei had longer antennae, but less dense sensilla. Combined, our experiments suggest that the effects of juvenile diet on investment in reproductive traits, including those associated with signalling, differ between males and females. Females allocate nutrients to adult body size, which determines fecundity. In contrast, males allocate nutrients to adult longevity and antennae size, both of which improve mate search and mating success. [ABSTRACT FROM AUTHOR]

Sexual conflict is prevalent among animals and is primarily caused by the fact that the optimal mating rates are often higher in males than in females. While there is a growing appreciation that females can also gain from multiple matings, we still know relatively little about which sex controls the observed mating rates and how close it is to the optimal female mating rates. To address this issue, we tracked female bed bugs (Cimex lectularius) inseminated daily versus weekly and found that weekly inseminated females lived longer and produced over 50% more offspring. In a follow-up experiment employing a social network framework, we placed 24 bed bugs into a semi-naturalistic arena and recorded all sexual interactions. While recently inseminated females did not avoid males more often, they were more frequently rejected by males. Finally, we tracked avoidance behaviour in a single cohort of female bed bugs as they received six successive daily inseminations. Avoidance rates increased and insemination durations decreased with increasing number of prior inseminations. Overall, our results indicate high costs of polyandry. Although females possess some plastic avoidance strategies, the observed rates of insemination fall closer to the male rather than female optimum. [ABSTRACT FROM AUTHOR]

Past reproductive effort allows males to assess their ability to acquire mates, but it also consumes resources that can reduce their future competitive ability. Few studies have examined how a male's reproductive history affects his subsequent mate choice, and, to date, no study has determined the relative contribution of past mating behavior and past ejaculate production because these two forms of investment are naturally highly correlated. Here, we disentangled the relative effects of past mating behavior and past ejaculate production in mosquitofish (Gambusia holbrooki) by experimentally preventing some males from ejaculating when trying to mate. We assessed the effect of mating behavior on mate choice by comparing males that had previously been with or without access to females and male rivals for 8 and 16 weeks and assessed the effect of ejaculation on mate choice by comparing males that either could or could not ejaculate when they had access to females for 16 weeks. Reproductive treatment did not affect male attractiveness, but it did affect male mate choice. Somewhat surprisingly, in five of the six treatment-by-age at testing combinations, males preferred a female in the vicinity of a male rival over a solitary female. This preference was marginally stronger for males that had previously engaged in mating behavior but were unaffected by past ejaculate production. We discuss the potential benefits to males of associating with another male when seeking mates. This is the first study to quantify the relative influence of pre- and post-copulatory reproductive investment on male mate choice. [ABSTRACT FROM AUTHOR]

Behavior, like most other traits, can have a spatial component, and variability of behavior at the population level is predicted. In this article, we explore male mate choice at this level. Male mate choice, while maybe not as common as female choice, is expected to evolve when males respond to significant variation in female quality and, for example, prefer females with higher fecundity. In fishes, higher fecundity is associated with larger body size, an easily measured trait. In this study, we investigated the presence of male mate choice for larger females in a widespread species of livebearing fish, Limia perugiae , while comparing preferences between populations. We hypothesized that environmental variation, for example, in the form of salinity, might result in population differences. Using dichotomous choice tests, we analyzed behavioral data for 80 individuals from 7 distinct populations from Hispaniola. We found that L. perugiae males significantly preferred large females, but there was no significant statistical variation between populations. [ABSTRACT FROM AUTHOR]

It is assumed that males increase their reproductive performance by mating with the highest number of females. However, in some species males are reproductively constrained, being able to mate only a few times. In these cases, it is expected that males choose the highest quality females available. One factor that can change female quality is parasitism, however, many empirical studies fail to find conclusive support for a non‐parasitized female preference. This might be due to the fact that behavioral tests in many studies are made in a controlled environment or use indirect measures of mate choice. Using a natural‐environment approach, we tested whether the mate choice of the golden orb‐web spider Trichonephila clavipes male is affected by the presence of the parasite in the female. We hypothesize that males will prefer to establish on webs of non‐parasitized females and will attempt to mate and copulate more with non‐parasitized females over parasitized ones. For this, we conducted field observations for 76 h. We found that males prefer to establish on non‐parasitized female webs than on parasitized ones. However, there was no difference between the number of attempts to mate and copulations of parasitized and non‐parasitized females. It seems that males can distinguish between parasitized and non‐parasitized females, but once they establish on a female web, they are resistant to leave. One possible explanation is that some males stay on a parasitized female web to avoid competition with other males. Therefore, it is possible that mating with parasitized females represents a "making the best of a bad job" mating tactic in T. clavipes. [ABSTRACT FROM AUTHOR]

Theory predicts that the strength of male mate choice should vary depending on male quality when higher‐quality males receive greater fitness benefits from being choosy. This pattern extends to differences in male body size, with larger males often having stronger pre‐ and post‐copulatory preferences than smaller males. We sought to determine whether large males and small males differ in the strength (or direction) of their preference for large, high‐fecundity females using the fruit fly, Drosophila melanogaster. We measured male courtship preferences and mating duration to show that male body size had no impact on the strength of male mate choice; all males, regardless of their size, had equally strong preferences for large females. To understand the selective pressures shaping male mate choice in males of different sizes, we also measured the fitness benefits associated with preferring large females for both large and small males. Male body size did not affect the benefits that males received: large and small males were equally successful at mating with large females, received the same direct fitness benefits from mating with large females, and showed similar competitive fertilization success with large females. These findings provide insight into why the strength of male mate choice was not affected by male body size in this system. Our study highlights the importance of evaluating the benefits and costs of male mate choice across multiple males to predict when differences in male mate choice should occur. [ABSTRACT FROM AUTHOR]

The function of female ornamentation in (inter)sexual selection is attracting increasing attention, but empirical field studies are mostly based on indirect measures such as mating patterns; direct evidence of male mate preference on female ornamentation while controlling for confounding factors is needed. Here, we performed model presentation experiments to study male mate preference in the barn swallow Hirundo rustica, a model species of sexual selection. Although female tails are shorter than male tails in the barn swallow, they are still long and indicate female quality, possibly due to the differential costs of ornamentation. Although many correlational and experimental studies of live females have focused on long tails in female barn swallows over the last three decades, direct behavioral tests of male mate preference are lacking. In our sequential model presentation experiment, in which we repeated the trials with the same males, we found that males significantly reduced the number of pairing displays when presented with tail‐elongated female models compared to controls. The interaction between treatment and male tail length was far from significant. The observed pattern is inconsistent with the prevailing view that female ornamentation is maintained via male preference for more ornamented females; rather, it is consistent with the sexual mimicry hypothesis, in which females can avoid sexual and social harassment by mimicking males. [ABSTRACT FROM AUTHOR]

Cryptic male mate choice occurs when males differentially allocate resources to females during or after copulation. When male resources are limited, males may benefit by strategically allocating more resources toward higher-quality females. In the fruit fly, Drosophila melanogaster , males mate for longer and may transfer more sperm and more seminal proteins when they mate with larger females compared with smaller females. It is unclear, however, whether this increased investment in large females has any impact on the males' later matings. We mated D. melanogaster males sequentially to females of large or small body size in all possible combinations to test whether cryptic male mate choice for large females is costly to the males' subsequent matings. Second matings were shorter for males compared with their first matings, but there were no differences in fecundity between females mated first or second by a male. Interestingly, male success at defensive sperm competition declined between his first and second matings only when his first mating had been with a large female. This suggests that the higher initial investment in large females reduced male postcopulatory success in their subsequent matings. Cryptic male mate choice may carry underappreciated costs to males that could limit their reproductive potential. [ABSTRACT FROM AUTHOR]

Inbreeding can result in inbreeding depression. Therefore, many species seek to avoid inbreeding. However, theory predicts that inbreeding can be beneficial. Accordingly, some species tolerate inbreeding or even prefer mating with close relatives. Evidence for active inbreeding, i.e., kin-mating preference was reported in the biparental African cichlid fish Pelvicachromis taeniatus. Related mating partners revealed better parental cooperation due to kin selection, a potential benefit of inbreeding. In this study, we investigated kin-mating preference in a genetically diverse, outbred F2-lab population of Pelvicachromis pulcher, a closely related species to P. taeniatus. Like P. taeniatus, this species shows mutual ornamentation and mate choice as well as intense biparental brood care. The F1 P. pulcher generation had revealed signs of inbreeding depression but no inbreeding avoidance. We studied mating behavior and aggression in trios consisting of a male P. pulcher, an unfamiliar sister, and an unfamiliar, unrelated female. Because the study focused on kin-mating patterns, female pairs were matched for body size and coloration. The results provide no evidence for inbreeding avoidance but rather suggest inbreeding preference. We also found no significant impact of inbreeding on offspring survival. The results suggest no inbreeding avoidance in P. pulcher; however, the strength of inbreeding preference and inbreeding depression seems to be variable. We discuss possible causes for this variation like context-dependent inbreeding depression. The number of eggs positively correlated with female body size and coloration. Furthermore, the female aggressiveness was positively correlated with female coloration indicating that coloration signal female dominance and quality. [ABSTRACT FROM AUTHOR]

Abstract Background Mate choice is a fundamental element of sexual selection and has the potential to shape the evolution of traits. Mate choice based on body size has been shown to be a common trait in several arthropod species. In hard ticks, a taxon of medical and veterinary importance, engorgement weight is positively correlated with reproductive output but it is unknown whether adult males show mate choice. Here, we experimentally investigated whether males (i) use chemical cues to choose their mating partner, (ii) consistently choose for the same female individual and (iii) prefer females with highest weight after feeding. Methods We used two experimental setups which allowed chemical communication between ticks: (i) a horizontal tube preventing physical contact with the female and (ii) an arena where tactile cues were allowed. In total, we tested 62 different triads in 124 tests (66 tests in the horizontal tube and 58 in the arena) composed of one male that could choose between two engorged females. Specifically, we tested 42 triads in the tube and 46 in the arena; 24 triads were repeatedly tested in the tube while 38 triads were tested in both setups. Results We found no preference for individual or heavier females in either setup. However, in the horizontal tube setup, males significantly preferred females that were not visited by them in the previous test. Conclusions Our results suggest a lack of male mate choice despite heavier females having higher fecundity. However, future studies should take into account that males may recognize the potential mating partners they previously met. Graphical Abstract

Abstract Background Despite its important implications in behavioural and evolutionary ecology, male mate choice has been poorly studied, and the relative contribution of personality and morphological traits remains largely unknown. We used standard two-choice mating trials to explore whether two personality traits (i.e., shyness and activity) and/or body size of both sexes affect mate choice in male mosquitofish Gambusia affinis. In the first set of trials involving 40 males, we tested whether males would prefer larger females and whether the preference would be affected by males’ body length and personality traits, and females’ activity level. In the second set of trials (using another 40 males), we tested whether males would prefer more active females and whether the preference would be affected by males’ body length and personality traits. Results Both shyness and activity in males were significantly repeatable and constituted a behavioural syndrome. No overall directional preference for large (or small) females with the same activity levels was detected because larger males preferred larger females and smaller males chose smaller females. Males’ strength of preference for larger females was also positively correlated with the activity level of larger females but negatively with the activity level of smaller females. Males spent more time associating with active females regardless of their body lengths, indicating males’ selection was more influenced by female activity level than body size. Males’ preference for inactive females was enhanced when females became active. There was no convincing evidence for the effect of males’ personality traits or body length on their preferences for females’ activity level. Conclusions Our study supports the importance of body size in male mate choice but highlights that personality traits may outweigh body size preferences when males choose mating partners.

Abstract Although females are traditionally thought of as the choosy sex, there is increasing evidence in many species that males will preferentially court or mate with certain females over others when given a choice. In the fruit fly, Drosophila melanogaster, males discriminate between potential mating partners based on a number of female traits, including species, mating history, age, and condition. Interestingly, many of these male preferences are affected by the male's previous sexual experiences, such that males increase courtship toward types of females that they have previously mated with and decrease courtship toward types of females that have previously rejected them. D. melanogaster males also show courtship and mating preferences for larger females over smaller females, likely because larger females have higher fecundity. It is unknown, however, whether this preference shows behavioral plasticity based on the male's sexual history as we see for other male preferences. Here, we manipulate the sexual experience of D. melanogaster males and test whether this manipulation has any effect on the strength of male mate choice for large females. We find that sexually inexperienced males have a robust courtship preference for large females that is unaffected by previous experience mating with, or being rejected by, females of differing sizes. Given that female body size is one of the most common targets of male mate choice across insect species, our experiments with D. melanogaster may provide insight into how these preferences develop and evolve.

Background: Mate choice is a fundamental element of sexual selection and has the potential to shape the evolution of traits. Mate choice based on body size has been shown to be a common trait in several arthropod species. In hard ticks, a taxon of medical and veterinary importance, engorgement weight is positively correlated with reproductive output but it is unknown whether adult males show mate choice. Here, we experimentally investigated whether males (i) use chemical cues to choose their mating partner, (ii) consistently choose for the same female individual and (iii) prefer females with highest weight after feeding. Methods: We used two experimental setups which allowed chemical communication between ticks: (i) a horizontal tube preventing physical contact with the female and (ii) an arena where tactile cues were allowed. In total, we tested 62 different triads in 124 tests (66 tests in the horizontal tube and 58 in the arena) composed of one male that could choose between two engorged females. Specifically, we tested 42 triads in the tube and 46 in the arena; 24 triads were repeatedly tested in the tube while 38 triads were tested in both setups. Results: We found no preference for individual or heavier females in either setup. However, in the horizontal tube setup, males significantly preferred females that were not visited by them in the previous test. Conclusions: Our results suggest a lack of male mate choice despite heavier females having higher fecundity. However, future studies should take into account that males may recognize the potential mating partners they previously met. [ABSTRACT FROM AUTHOR]

The prevalence and diversity of female ornaments poses a challenge to evolutionary theory because males should prefer mates that spend resources on offspring rather than ornaments. Among dance flies, there is extraordinary variation in sexual dimorphism. Females of many species have conspicuous ornaments (leg scales and inflatable abdominal sacs). Meanwhile males of some species have exaggerated regions of their eyes with larger ommatidial facets that allow for regionally elevated photosensitivity and/or acuity. Here, we conduct a comparative study of these traits using both species descriptions available from the literature, as well as quantitative measures of eyes and ornaments from wild-caught flies. We show a conspicuous covariance across species between exaggerated male dorsal eye regions and the extent of female ornaments: species with highly ornamented females have males with more exaggerated eyes. We discuss this pattern in the context of competing hypotheses for the evolution of these traits and propose a plausible role for sexually antagonistic coevolution., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Society for the Study of Evolution (SSE).)

Male mate choice occurs in several animal species, but we know little about the factors that influence the expression of this behaviour. Males vary in their capacity to acquire mates (i.e. male quality), which could be crucial to male mate choice expression but it is often overlooked. Using a meta‐analytical approach, we explore interindividual variation in the expression of male mate choice by comparing the mating investment of males of different qualities and phenotypes to high‐ and low‐quality females. We used two datasets that together contained information from 60 empirical studies, comprising 52 species. We found that males of all qualities and phenotypes prefer high‐quality females, but differ in the strength of such preference. High‐ and medium‐quality males are choosier than low‐quality males. Similarly, males that are larger or in greater body condition are choosier than their counterparts. In contrast, male body mass and age are not associated with changes in male mate choice. We also show that experimental design may influence our understanding of male mating investment patterns, which may limit the generalisation of our findings. Nonetheless, we argue that male quality may be an important feature in the expression of male mate choice. [ABSTRACT FROM AUTHOR]

Insect cuticular hydrocarbons provide desiccation resistance but may also be used in chemical signalling. Sexually dimorphic hydrocarbon blends, which may be transferred between individuals during copulation, are used especially in mate assessment. However, not all insect species produce sex-specific hydrocarbon blends, and their general utility in mate choice requires study of a broader range of species than is currently available. In the nuptial gift-giving bushcricket Kawanaphila nartee , sex roles vary depending on food availability: when food is scarce, females compete for access to males and their nuptial gifts, and when food is abundant, males compete for access to females. Given the scope for both male and female mate choice in the species, we hypothesized that their cuticular hydrocarbon profiles would differ. We characterized the cuticular hydrocarbon profiles of male and female K. nartee and found significant differences between them. Given the costly nutrient gifts provided by males at mating, we further hypothesized that males might use hydrocarbon residues left by rival males after mating to avoid investing in offspring sired by other males. Although females perfumed with male-derived hydrocarbon blends had lower mating success than control females, the difference was not statistically significant. We discuss the possible mechanisms that might favour the evolution of sexual dimorphism in cuticular hydrocarbon blends in this species. • Sexual dimorphism in cuticular hydrocarbons occurs in a sex role reversing insect. • Sexual dimorphism in hydrocarbons is not used by males in mate discrimination. • The dimorphism nevertheless provides a mechanism for sex discrimination. • The dimorphism may be used in mate choice by one or both sexes. [ABSTRACT FROM AUTHOR]

Abstract Background When males are selective, they can either reject low-quality females or adjust their reproductive investment in response to traits that indicate female quality (e.g., body size or condition). According to the differential allocation hypothesis, males increase their reproductive investment when paired with high-quality females (positive differential allocation) or increase their reproductive investment when paired with low-quality females (negative differential allocation). This hypothesis has been proposed for monogamous species with biparental care, and most empirical studies focus on birds. Here we used the polygamous spider Paratrechalea ornata, in which males offer prey wrapped in silk as nuptial gifts, to test whether males adjust their reproductive investment in gift size, pre-copulatory and copulatory courtship, and sperm transfer in response to female body condition. Results Males exposed to females in good body condition added more flies to the gift, stimulated these females longer with abdominal touches during pre-copulatory courtship, and had longer pedipalp insertions than males exposed to females in poor body condition. Female condition affected neither silk investment in nuptial gift wrapping nor the quantity of sperm transferred by males. Finally, females in good body condition oviposited faster after copulation and laid more eggs than females in poor body condition. Conclusions We provide experimental evidence that males of a gift-giving spider exhibit positive differential allocation in three key aspects of their reproductive investment: the size of the nutritious gift, duration of pre-copulatory courtship, and duration of pedipalp insertions, which is regarded as a form of copulatory courtship in spiders. This positive differential allocation is likely associated with the benefits of copulating with females in good body condition. These females are more fecund and oviposit faster after copulation than females in poor body condition, which under natural field conditions probably reduces the risk of multiple matings and thus the level of sperm competition faced by the males. As a final remark, our findings indicate that the hypothesis of differential allocation also applies to species with a scramble competition mating system, in which males heavily invest in nuptial gift construction, but not in parental care.

Abstract Sexual conflict can result in coercive mating. Because males bear low costs of heterospecific mating, coercive males may engage in misdirected mating attempts toward heterospecific females. In contrast, sexual selection through consensual mate choice can cause mate recognition cues among species to diverge, leading to more accurate species recognition. Some species show both coercive mating and mate choice‐associated courtship behaviors as male alternative reproductive tactics. We hypothesized that if the selection pressures on each tactic differ, then the accuracy of species recognition would also change depending on the mating tactic adopted. We tested this hypothesis in the guppy (Poecilia reticulata) and mosquitofish (Gambusia affinis) by a series of choice experiments. Poecilia reticulata and G. affinis males both showed imperfect species recognition and directed all components of mating behavior toward heterospecific females. They tended to direct courtship displays more frequently toward conspecific than heterospecific females. With male P. reticulata, however, accurate species recognition disappeared when they attempted coercive copulation: they directed coercions more frequently toward heterospecific females. We also found that heterospecific sexual interaction had little effect on the fecundity of gravid females, which suggests that prepregnancy interactions likely underpin the exclusion of G. affinis by P. reticulata in our region.

Few studies have looked at variation in male mating strategies in relation to phenotypic quality perhaps because males are not traditionally thought to be choosy. Recent theoretical models, however, predict that body condition should affect mating preferences. In crayfish, chelae are important weapons and may be reliable indicators of quality in both sexes. Here, we investigated mating preference in male red swamp crayfish, Procambarus clarkii , of standardized size and different chelae condition. In the first experiment, the quality of each crayfish was classified according to whether both chelae were intact or lost. We compared the mating preferences of high-quality males (two chelae) and low-quality males (no chelae) when choosing high- and low-quality females. The second experiment explored whether males with a single chela chose females based on their single chela side (left-clawed and right-clawed). The results showed that high-quality males were not choosy, while low-quality males preferred high-quality females. Left-clawed males preferred right-clawed females, but right-clawed males did not discriminate between partners based on chela side. We consider this may be due to an adaptation in mating strategies and handedness. Our study suggests a conditional male mating strategy based on quality and symmetry which could maintain the success of copulation regardless of chelae loss. • Males of red swamp crayfish adjust mating strategy depending on chelae condition. • High-quality males are unselective. • Low-quality males show preference for high-quality females. • Males with single left and right chela both prefer mirror-symmetry females. [ABSTRACT FROM AUTHOR]

Background: Despite its important implications in behavioural and evolutionary ecology, male mate choice has been poorly studied, and the relative contribution of personality and morphological traits remains largely unknown. We used standard two-choice mating trials to explore whether two personality traits (i.e., shyness and activity) and/or body size of both sexes affect mate choice in male mosquitofish Gambusia affinis. In the first set of trials involving 40 males, we tested whether males would prefer larger females and whether the preference would be affected by males' body length and personality traits, and females' activity level. In the second set of trials (using another 40 males), we tested whether males would prefer more active females and whether the preference would be affected by males' body length and personality traits. Results: Both shyness and activity in males were significantly repeatable and constituted a behavioural syndrome. No overall directional preference for large (or small) females with the same activity levels was detected because larger males preferred larger females and smaller males chose smaller females. Males' strength of preference for larger females was also positively correlated with the activity level of larger females but negatively with the activity level of smaller females. Males spent more time associating with active females regardless of their body lengths, indicating males' selection was more influenced by female activity level than body size. Males' preference for inactive females was enhanced when females became active. There was no convincing evidence for the effect of males' personality traits or body length on their preferences for females' activity level. Conclusions: Our study supports the importance of body size in male mate choice but highlights that personality traits may outweigh body size preferences when males choose mating partners. [ABSTRACT FROM AUTHOR]

In the classic theory of sexual roles, females are more careful in their choice of a mate because their reproductive investment is relatively higher. However, increasing evidence shows that males can also be choosy. Mate choice can be based on physical characteristics, such as body size and color ornaments, which have been documented as factors that also influence the maintenance of polymorphism. Here, we experimentally tested whether males of the annual killifish Millerichthys robustus preferentially choose females according to variations in ocelli number on the base of the caudal fin, or according to body size, in classical dual decision experiments. We demonstrated that there is a strong preference of the males of M. robustus for females with greater numbers of ocelli on the base of the caudal fin (females with 5–7 versus 1–2 ocelli) and for females of larger body size. We also tested whether female body size or number of ocelli are linked to higher fecundity or increased egg size, quantifying the number of embryos produced by the females of each experimental group and measuring the size of their eggs. Our results revealed that large females with more ocelli produced more and larger eggs than large females with fewer ocelli, and than small females regardless of the number of ocelli. These results may suggest that males of M. robustus that choose large-sized females can mate with genetic quality in parameters directly related to biological success, such as higher egg production of large-sized eggs. This is probably related to a higher hatching percentage, and larger subsequent larvae with rapid growth rates. We therefore propose that large body size and high number of ocelli on the base of the caudal fin in females could have evolved through male mate choice. [ABSTRACT FROM AUTHOR]

Although females are traditionally thought of as the choosy sex, there is increasing evidence in many species that males will preferentially court or mate with certain females over others when given a choice. In the fruit fly, Drosophila melanogaster, males discriminate between potential mating partners based on a number of female traits, including species, mating history, age, and condition. Interestingly, many of these male preferences are affected by the male's previous sexual experiences, such that males increase courtship toward types of females that they have previously mated with and decrease courtship toward types of females that have previously rejected them. D. melanogaster males also show courtship and mating preferences for larger females over smaller females, likely because larger females have higher fecundity. It is unknown, however, whether this preference shows behavioral plasticity based on the male's sexual history as we see for other male preferences. Here, we manipulate the sexual experience of D. melanogaster males and test whether this manipulation has any effect on the strength of male mate choice for large females. We find that sexually inexperienced males have a robust courtship preference for large females that is unaffected by previous experience mating with, or being rejected by, females of differing sizes. Given that female body size is one of the most common targets of male mate choice across insect species, our experiments with D. melanogaster may provide insight into how these preferences develop and evolve. [ABSTRACT FROM AUTHOR]

Behaviours that are consistent across contexts (also known as behavioural syndromes) can have evolutionary implications, but their role in scenarios where the sexes conflict, such as sexual cannibalism, is poorly understood. While some research has focused on aggressive personality in females and its role in determining cannibalistic attack, effects of male personality have rarely been explored. Male activity as a personality trait could be an important mediator of sexual cannibalism if it modulates how quickly or carelessly males approach females, but such a relationship has never been tested. Here, we used the springbok mantis, Miomantis caffra , to explore effects of male activity levels and female aggressiveness on mating behaviour and sexual cannibalism. We found that male activity and subadult female aggressiveness were repeatable, although the latter only marginally so. Females that were aggressive as juveniles were not more likely to cannibalize males when adult following physical interaction, but males made physical contact with these females sooner and more often. More active males were both faster and more likely to interact with females, but were not more likely to be cannibalized in the process. We also found that female age influenced sexual interactions: younger females were more likely to cannibalize males. Taken together, our results suggest that both male and female personality influence the likelihood of sexual encounter, but have little effect on the likelihood of cannibalism. Our study highlights the potential for the personality traits of both sexes to influence mating dynamics in sexually cannibalistic species. • Females were barely consistent in their aggressiveness as subadults. • Male activity was consistent in the adult stage. • Males interacted sooner and more often with females that were more aggressive. • More active males made physical contact with females earlier and more frequently. • Older females were less likely to cannibalize males that interacted with them. [ABSTRACT FROM AUTHOR]

Sexual communication in mate choice scenarios involves nonmutually exclusive functions: species recognition, mate location and mate assessment. Most studies on sexual communication in mate choice have focused on female assessment of conspicuous male traits, such as visual and acoustic signals. Only a few studies have addressed male assessment of female traits, especially those that are inconspicuous to the human sensory system, such as chemical signals. Although chemical signals are important in sexual communication of many arachnids, there is a gap in our knowledge about how male scorpions use these signals to evaluate potential partners. Here we studied sexual communication functions in two scorpion species (Urophonius brachycentrus and Urophonius achalensis) with sympatric populations and synchronic reproduction, where males are under a scramble competition mating system. We addressed the volatile pheromones role in each of the sexual communication functions. We used Y-mazes to test volatile pheromones, exposing males to different female stimulus arrays in single-signal (conspecific only) and mixed-signal (conspecific and heterospecific) contexts. Males located conspecific females through volatile pheromones, and the time spent in proximity to the female was proportional to males' perception of the female's quality, reinforcing the pheromones' function in mate location and assessment in single-signal environments. However, these sexually selected functions were overridden in mixed-signal contexts, in which males could not differentiate conspecific from heterospecific females, suggesting that pheromones do not allow species recognition. This interaction between sexual communication functions can lead to reproductive interference in this sympatric zone. Male indiscriminateness mediated by scramble competition could attenuate pheromones' species recognition function during mate choice. We provide a comprehensive study of the pheromones' role for mate and species recognition in different social contexts in scorpions. We found support for nonindependent and interacting functions of sexual communication, indicating that mate choice is a complex process in scorpions. • Males of Urophonius species detect conspecific females through volatile pheromones. • In single-signal contexts, males use sex pheromones to locate and assess females. • However, sex pheromones do not allow species recognition in this scorpion species. • Scramble competition could promote male indiscriminateness in mixed-signal contexts. • Interaction between sexual communication functions leads to reproductive interference. [ABSTRACT FROM AUTHOR]

Abstract Background Mate choice is a taxonomically wide-spread phenomenon, mostly exerted by females although male mate choice occurs as well. While costs and benefits of choosiness have been well studied, the underlying mechanisms are largely unclear. Different models exist, namely best-of-n or threshold rules, based on sequential or simultaneous sampling, which differ in the required cognitive demands. We applied an experimental approach to shed light on the underlying mechanisms of male mate choice in the sexually cannibalistic spider Argiope bruennichi. Males are limited to two copulations and preferentially monopolise large females, while they may leave smaller females after a single copulation and resume mate search. Here, we utilised significant size-differences between females from Northern and Southern populations and presented males with three different-sized females that were matched for origin: all three females originated either from the same Northern European population as the males or from Southern populations where the smallest female was about the same size as the largest Northern female. This allowed testing the hypothesis that males base their mating tactic on a fixed local size threshold. We predicted Northern males to be choosy among Northern females, but to accept all Southern females since they would all be above that threshold. Results Males copulated with the first female they encountered, which was independent of her body size. Regardless of the females’ origins, males chose a monogynous tactic with the largest female in the trio, while they left the smallest female after one copulation. The same pattern applied to Southern females even though the smallest females in the trio were of a similar size as monopolised Northern females. Since males have poor eyesight and did not actively sample all females, they likely have gained information about relative size differences between females based on volatile chemical cues only. Conclusions Our findings suggest that male A. bruennichi can assess relative differences in mate quality and adjust their mating tactic to the prevailing conditions (Northern vs. Southern). We reject the presence of a locally-adapted fixed threshold and argue that our results are best explained by an adjustable threshold that was raised under Southern conditions.

Abstract Reinforcement occurs when selection against hybrid offspring strengthens behavioral isolation between parental species and may be an important factor in speciation. Theoretical models and experimental evidence indicate that both female and male preferences can be strengthened upon secondary contact via reinforcement. However, the question remains whether this process is more likely to affect the preferences of one sex or the other. Males of polygynous species are often predicted to exhibit weaker preferences than females, potentially limiting the ability for reinforcement to shape male preferences. Yet, in darters (Percidae: Etheostoma), male preference for conspecific mates appears to arise before female preferences during the early stages of allopatric speciation, and research suggests that male, but not female, preferences become reinforced upon secondary contact. In the current study, we aimed to determine whether the geographically widespread darter species Etheostoma zonale exhibits a signature of reinforcement, by comparing the strength of preference for conspecific mates between populations that are sympatric and allopatric with respect to a close congener, E. barrenense. We examined the strength of preference for conspecifics for males and females separately to determine whether the preferences of one or both sexes have been strengthened by reinforcement. Our results show that both sexes of E. zonale from sympatric populations exhibit stronger conspecific preferences than E. zonale from allopatric populations, but that female preferences appear to be more strongly reinforced than male preferences. Results therefore suggest that reinforcement of female preferences may promote behavioral isolation upon secondary contact, even in a genus that is characterized by pervasive male mate choice.

Species of flies in the genus Drosophila differ dramatically in their preferences for mates, but little is known about the genetic or neurological underpinnings of this evolution. Recent advances have been made to our understanding of one case: pheromone preference evolution between the species D. melanogaster and D. simulans. Males of both species are very sensitive to the pheromone 7,11-HD that is present only on the cuticle of female D. melanogaster. In one species this cue activates courtship, and in the other it represses it. This change in valence was recently shown to result from the modification of central processing neurons, rather than changes in peripherally expressed receptors, but nothing is known about the genetic changes that are responsible. In the current study, we show that a 1.35 Mb locus on the X chromosome has a major effect on male 7,11-HD preference. Unfortunately, when this locus is divided, the effect is largely lost. We instead attempt to filter the 159 genes within this region using our newfound understanding of the neuronal underpinnings of this phenotype to identify and test candidate genes. We present the results of these tests, and discuss the difficulty of identifying the genetic architecture of behavioral traits and the potential of connecting these genetic changes to the neuronal modifications that elicit different behaviors.

Males are expected to mate with as many females as possible, but can maximize their reproductive success through strategic mating decisions. For instance, males can increase their own fitness by mating with high quality females that produce more offspring. Additionally, males can adjust mating effort based on the relative distribution of females and male competitors. To test factors that influence male mate choice, we assessed male mating decisions in the golden silk orb-weaver spider, Trichonephila clavipes (Nephilidae), a species in which females are polyandrous, males guard females before and after copulation occurs and large males are the most successful at guarding mates. We tested the hypothesis that males spend more time guarding high quality females that are spatially isolated, and when the risk of sperm competition is higher. We also hypothesized that this effect increases with male body size. We assessed solitary and aggregated female webs in the field and quantified female quality (i.e., female body condition), male size (i.e., male body size), the risk of sperm competition (i.e., number of males in each female web), and mate-guarding duration (i.e., number of days each male spent in each web). We found that mate-guarding behaviour is largely influenced by the presence of male competitors. In addition, male body size seems to moderately influence male guarding decisions, with larger males guarding for a longer time. Finally, female body condition and type of web (i.e., solitary or aggregated) seem to play small roles in mate-guarding behaviour. As mate-guarding duration increased by 0.718 day per each additional male competitor in the web, and guarding behaviour prevents males from seeking additional mates, it seems that guarding females can be considerably costly. We conclude that failing to guard a sexual partner promotes high costs derived from sperm competition, and a male cannot recover his relative loss in fertilization success by seeking and fertilizing more females. In addition, the search for more sexual partners can be constrained by possible high costs imposed by weight loss and fights against other males, which may explain why the type of web only moderately influenced male mate choice. Following the same rationale, if high-quality females are not easy to find and/or mating with a high-quality female demands much effort, males may search females and guard them regardless of female quality. In conclusion, the factor that most influences male mate-guarding behaviour among T. clavipes in the field is the risk of sperm competition. [ABSTRACT FROM AUTHOR]

In scramble competition mating systems, males do not guard females and females usually mate polyandrously, leading to high levels of sperm competition. Mathematical models predict that males facing sperm competition can either decrease or increase their reproductive effort. To test how male reproductive responses vary according to sperm competition risk, we ran two experiments using the polyandrous gift‐giving spider Paratrechalea ornata. First, we tested whether males prefer substrates containing silk of unmated females than substrates containing silk of once‐mated females, competitor males or without silk. Males spent more time on substrates containing silk of females but showed no preference for unmated females, which indicates that males may optimize mate search by prioritizing substrates containing cues of potential mating partners. The lack of preference for unmated females suggests that males cannot detect female mating status from silk or that the costs of searching preferentially for unmated females are high in the field. Second, we tested whether males adjust prey‐gift construction when facing sperm competition risk. Experimental groups (substrate containing silk of an unmated female and silk of another male vs. substrate containing only silk of an unmated female) did not differ in the frequency of gift construction, latency to gift construction and number of flies added to the gift. However, males facing sperm competition risk constructed gifts with less silk, suggesting the occurrence of a less evident form of male mate choice based on differential allocation of resources to prey‐gift. Additionally, given the trade‐off between investing in prey‐gifts quantity or quality, a lower silk investment should enable males to increase the number of gifts constructed and the number of courted females. Taken together, our results indicate that males detect female and male pheromones on substrate and adjust the construction of prey‐gifts in response to apparent sperm competition risk. [ABSTRACT FROM AUTHOR]

Males are expected to mate with as many females as possible, but can maximize their reproductive success through strategic mating decisions. For instance, males can increase their own fitness by mating with high quality females that produce more offspring. Additionally, males can adjust mating effort based on the relative distribution of females and male competitors. To test factors that influence male mate choice, we assessed male mating decisions in the golden silk orb-weaver spider, Trichonephila clavipes (Nephilidae), a species in which females are polyandrous, males guard females before and after copulation occurs and large males are the most successful at guarding mates. We tested the hypothesis that males spend more time guarding high quality females that are spatially isolated, and when the risk of sperm competition is higher. We also hypothesized that this effect increases with male body size. We assessed solitary and aggregated female webs in the field and quantified female quality (i.e., female body condition), male size (i.e., male body size), the risk of sperm competition (i.e., number of males in each female web), and mate-guarding duration (i.e., number of days each male spent in each web). We found that mate-guarding behaviour is largely influenced by the presence of male competitors. In addition, male body size seems to moderately influence male guarding decisions, with larger males guarding for a longer time. Finally, female body condition and type of web (i.e., solitary or aggregated) seem to play small roles in mate-guarding behaviour. As mate-guarding duration increased by 0.718 day per each additional male competitor in the web, and guarding behaviour prevents males from seeking additional mates, it seems that guarding females can be considerably costly. We conclude that failing to guard a sexual partner promotes high costs derived from sperm competition, and a male cannot recover his relative loss in fertilization success by seeking and fertilizing more females. In addition, the search for more sexual partners can be constrained by possible high costs imposed by weight loss and fights against other males, which may explain why the type of web only moderately influenced male mate choice. Following the same rationale, if high-quality females are not easy to find and/or mating with a high-quality female demands much effort, males may search females and guard them regardless of female quality. In conclusion, the factor that most influences male mate-guarding behaviour among T. clavipes in the field is the risk of sperm competition.

Background: When males are selective, they can either reject low-quality females or adjust their reproductive investment in response to traits that indicate female quality (e.g., body size or condition). According to the differential allocation hypothesis, males increase their reproductive investment when paired with high-quality females (positive differential allocation) or increase their reproductive investment when paired with low-quality females (negative differential allocation). This hypothesis has been proposed for monogamous species with biparental care, and most empirical studies focus on birds. Here we used the polygamous spider Paratrechalea ornata, in which males offer prey wrapped in silk as nuptial gifts, to test whether males adjust their reproductive investment in gift size, pre-copulatory and copulatory courtship, and sperm transfer in response to female body condition. Results: Males exposed to females in good body condition added more flies to the gift, stimulated these females longer with abdominal touches during pre-copulatory courtship, and had longer pedipalp insertions than males exposed to females in poor body condition. Female condition affected neither silk investment in nuptial gift wrapping nor the quantity of sperm transferred by males. Finally, females in good body condition oviposited faster after copulation and laid more eggs than females in poor body condition. Conclusions: We provide experimental evidence that males of a gift-giving spider exhibit positive differential allocation in three key aspects of their reproductive investment: the size of the nutritious gift, duration of pre-copulatory courtship, and duration of pedipalp insertions, which is regarded as a form of copulatory courtship in spiders. This positive differential allocation is likely associated with the benefits of copulating with females in good body condition. These females are more fecund and oviposit faster after copulation than females in poor body condition, which under natural field conditions probably reduces the risk of multiple matings and thus the level of sperm competition faced by the males. As a final remark, our findings indicate that the hypothesis of differential allocation also applies to species with a scramble competition mating system, in which males heavily invest in nuptial gift construction, but not in parental care. [ABSTRACT FROM AUTHOR]

The traditional view of sex roles and sexual selection emphasizes the evolution of male ornaments as a result of female mate choice and male–male competition. Female ornaments are now receiving more attention, although their roles in mating decisions are still less well understood, especially considering cases in which colourful ornaments are expressed by both sexes. In this study, we analysed whether female skin coloration (luminance and redness of the face and hindquarters) influenced male mate choice and sexual behaviours in relation to intracycle (cycle phase), intercycle (number of consecutive cycles, conceptive nature of the cycle) and interindividual (age, social rank, weight and parity) variation in a captive social group of Japanese macaques, Macaca fuscata. Males did not preferentially choose darker/redder females. Moreover, males did not appear to use female skin coloration to apportion their mating efforts on the fertile phase of the menstrual cycle or during cycles that led to conception, or to discriminate between females. Collectively, our results suggest that female skin coloration may not have been sexually selected in this species and that males mated regardless of such variation across females. To our knowledge, our study is among the few to report a lack of male choice for female coloration in a species where both sexes display ornamentation. Our findings provide novel insights on the role and evolution of female coloration in sexual signalling and mating decisions. • Nonsex-specific colourful traits can potentially influence mate choice. • In most primate species, it is unclear if males attend to colourful female traits. • We tested the effect of female coloration on male mate choice in Japanese macaques. • Males did not discriminate between/within females or cycles based on coloration. • Female coloration is unlikely to be a sexually selected trait in Japanese macaques. [ABSTRACT FROM AUTHOR]

Sexual conflict can result in coercive mating. Because males bear low costs of heterospecific mating, coercive males may engage in misdirected mating attempts toward heterospecific females. In contrast, sexual selection through consensual mate choice can cause mate recognition cues among species to diverge, leading to more accurate species recognition. Some species show both coercive mating and mate choice‐associated courtship behaviors as male alternative reproductive tactics. We hypothesized that if the selection pressures on each tactic differ, then the accuracy of species recognition would also change depending on the mating tactic adopted. We tested this hypothesis in the guppy (Poecilia reticulata) and mosquitofish (Gambusia affinis) by a series of choice experiments. Poecilia reticulata and G. affinis males both showed imperfect species recognition and directed all components of mating behavior toward heterospecific females. They tended to direct courtship displays more frequently toward conspecific than heterospecific females. With male P. reticulata, however, accurate species recognition disappeared when they attempted coercive copulation: they directed coercions more frequently toward heterospecific females. We also found that heterospecific sexual interaction had little effect on the fecundity of gravid females, which suggests that prepregnancy interactions likely underpin the exclusion of G. affinis by P. reticulata in our region. [ABSTRACT FROM AUTHOR]

Reinforcement can occur when maladaptive hybridization in sympatry favors the evolution of conspecific preferences and target traits that promote behavioral isolation (BI). In many systems, enhanced BI is due to increased female preference for conspecifics. In others, BI is driven by male preference, and in other systems both sexes exert preferences. Some of these patterns can be attributed to classic sex-specific costs and benefits of preference. Alternatively, sex differences in conspecific preference can emerge due to asymmetric postzygotic isolation (e.g. hybrid offspring from female A × male B have lower fitness than hybrid offspring from female B × male A), which can lead to asymmetric BI (e.g. female A and male B are less likely to mate than female B and male A). Understanding reinforcement requires understanding how conspecific preferences evolve in sympatry. Yet, estimating conspecific preferences can be difficult when both sexes are choosy. In this study, we use Lucania killifish to test the hypothesis that patterns of reinforcement are driven by asymmetric postzygotic isolation between species. If true, we predicted that sympatric female Lucania goodei and sympatric male L. parva should have lower levels of BI compared with their sympatric counterparts, as they produce hybrid offspring with the highest fitness. To address the problem of measuring BI when both sexes are choosy, we inferred the contribution to BI of each partner using assays where one sex in the mating pair comes from an allopatric population with potentially low preference, whereas the other comes from a sympatric population with high preference. For one hybrid cross direction, we found that both female L. parva and male L. goodei have high contributions to BI in sympatry. In the other hybrid cross direction, we found that only female L. goodei contribute to BI. Sympatric male L. parva readily engaged in hybrid spawnings with allopatric L. goodei females. These results indicate that both asymmetric postzygotic isolation and the traditional sex-specific costs to preference likely affect the nature of selection on conspecific preferences and target traits. [ABSTRACT FROM AUTHOR]

In sexually dimorphic species characterized by exaggerated male ornamentation, behavioral isolation is often attributed to female preferences for conspecific male signals. Yet, in a number of sexually dimorphic species, male mate choice also results in behavioral isolation. In many of these cases, the female traits that mediate species boundaries are unclear. Females in sexually dimorphic species typically lack many of the elaborate traits that are present in males and that are often used for taxonomic classification of species. In a diverse and largely sexually dimorphic group of fishes called darters (Percidae: Etheostoma), male mate choice contributes to behavioral isolation between a number of species; however, studies addressing which female traits males prefer are lacking. In this study, we identified the dominant female pattern for two sympatric species, Etheostoma zonale and Etheostoma barrenense , using pattern energy analysis, and we used discriminate function analysis to identify which aspects of female patterning can reliably classify species. We then tested the role of female features in male mate choice for E. zonale , by measuring male preference for computer animations displaying the identified (species-specific) conspecific features. We found that the region above the lateral line is important in mediating male mate preferences, with males spending a significantly greater proportion of time with animations exhibiting conspecific female patterning in this region than with animations exhibiting heterospecific female patterning. Our results suggest that the aspects of female phenotypes that are the target of male mate choice are different from the conspicuous male phenotypes that traditionally characterize species. [ABSTRACT FROM AUTHOR]

Male mate choice likely occurs when costs are associated with courtship or mating. For example, when males produce continuous vibrational signals, provide nutritious nuptial gifts, or are likely killed during mating, they should assess female developmental and reproductive state. Substrate‐borne vibratory courtship signals are very common in spiders serving species recognition, suppressing the female's aggression towards the male, or signalling individual quality. Males of the nursery web spider, Pisaura mirabilis, usually offer a prey item wrapped in silk as a nuptial gift to the female; the gift is commonly produced prior to female contact. When touching dragline silk deposited by a female, males tremulate their opisthosoma presumably reacting to chemical cues. Courtship energy expenditure and resource transfer should select for selective male mating decisions in this species. We hypothesized that male P. mirabilis differentiate between developmental stages of the female (sub‐adult vs. adult). Differential courtship towards virgin and mated females was not expected since females forage for nuptial gifts and might continuously signal receptivity. To test this, vibrational courtship signals of male spiders towards draglines of sub‐adult, adult unmated and mated females were recorded with a Laser Doppler Vibrometer. We found that males were less likely to perform vibrational courtship and produced less pulses when contacting silk of sub‐adult females, compared to silk produced by adult females, while their reaction towards silk of unmated and mated adult females did not differ. Reduced courtship in response to sub‐adult female silk seems beneficial since it reduces energy expenditure in the face of a not yet reproductive female. When vibratory courtship occurred, the temporal patterns and dominant frequencies of the males' vibratory signals were similar, regardless of female developmental stage or mating status. Such stable patterns suggest a role in species recognition already at a distance without direct physical contact and in reducing female aggression. [ABSTRACT FROM AUTHOR]

Abstract Informed mating decisions are often based on social cues providing information about prospective mating opportunities. Social information early in life can trigger developmental modifications and influence later mating decisions. A high adaptive value of such adjustments is particularly obvious in systems where potential mating rates are extremely limited and have to be carried out in a short time window. Males of the sexually cannibalistic spider Argiope bruennichi can achieve maximally two copulations which they can use for one (monogyny) or two females (bigyny). The choice between these male mating tactics should rely on female availability that males might assess through volatile sex pheromones emitted by virgin females. We predict that in response to those female cues, males of A. bruennichi should mature earlier and at a smaller body size and favor a bigynous mating tactic in comparison with controls. We sampled spiders from two areas close to the Southern and Northern species range to account for differences in mate quality and seasonality. In a fully factorial design, half of the subadult males from both areas obtained silk cues of females, while the other half remained without female exposure. Adult males were subjected to no‐choice mating tests and could either monopolize the female or leave her (bigyny). We found that Southern males matured later and at a larger size than Northern males. Regardless of their origin, males also shortened the subadult stage in response to female cues, which, however, had no effects on male body mass. Contrary to our prediction, the frequencies of mating tactics were unaffected by the treatment. We conclude that while social cues during late development elicit adaptive life history adjustments, they are less important for the adjustment of mating decisions. We suggest that male tactics mostly rely on local information at the time of mate search.

Background: Mate choice is a taxonomically wide-spread phenomenon, mostly exerted by females although male mate choice occurs as well. While costs and benefits of choosiness have been well studied, the underlying mechanisms are largely unclear. Different models exist, namely best-of-n or threshold rules, based on sequential or simultaneous sampling, which differ in the required cognitive demands. We applied an experimental approach to shed light on the underlying mechanisms of male mate choice in the sexually cannibalistic spider Argiope bruennichi. Males are limited to two copulations and preferentially monopolise large females, while they may leave smaller females after a single copulation and resume mate search. Here, we utilised significant size-differences between females from Northern and Southern populations and presented males with three different-sized females that were matched for origin: all three females originated either from the same Northern European population as the males or from Southern populations where the smallest female was about the same size as the largest Northern female. This allowed testing the hypothesis that males base their mating tactic on a fixed local size threshold. We predicted Northern males to be choosy among Northern females, but to accept all Southern females since they would all be above that threshold. Results: Males copulated with the first female they encountered, which was independent of her body size. Regardless of the females' origins, males chose a monogynous tactic with the largest female in the trio, while they left the smallest female after one copulation. The same pattern applied to Southern females even though the smallest females in the trio were of a similar size as monopolised Northern females. Since males have poor eyesight and did not actively sample all females, they likely have gained information about relative size differences between females based on volatile chemical cues only. Conclusions: Our findings suggest that male A. bruennichi can assess relative differences in mate quality and adjust their mating tactic to the prevailing conditions (Northern vs. Southern). We reject the presence of a locally-adapted fixed threshold and argue that our results are best explained by an adjustable threshold that was raised under Southern conditions. [ABSTRACT FROM AUTHOR]

Mating preferences vary among individuals in response to a number of factors, such as the age and phenotype of the choosing individual. However, studies addressing variation in mating preferences generally focus on female preferences and usually are limited to choice within a species. Variation in preferences likely also exists at the species boundary, affecting an individual's propensity to mate with heterospecific individuals. In darters (Percidae: Etheostoma), male mating preferences are thought to prevent interbreeding between species, with male preferences for conspecifics sometimes as strong as, or stronger than, females'. In the current study, we tested whether male size and coloration predicts preference for conspecific females in Etheostoma barrenense. Previous studies have shown that males of this species strongly prefer conspecific females relative to females of the sympatric congener, the banded darter, Etheostoma zonale ; however, those studies did not consider whether variation in male size or coloration affected preferences. Comparing large and small males of E. barrenense in dichotomous choice assays, we found that larger males exhibited stronger preferences for conspecific females and had proportionally more red coloration than smaller males. The proportion of red coloration did not significantly predict male preferences, suggesting that male size rather than male coloration predicts variation in male mating preferences for conspecific females in E. barrenense. Male size is often considered an indicator of individual quality. Alternatively, size might better reflect age in the focal species, suggesting that experience and learning may shape male preferences for conspecific females. • We investigated variation in male preference for conspecific females. • Categorically, large males preferred conspecific females, while small males did not. • As a continuous measure, male size predicted preference for conspecifics. • Male red coloration did not correlate with preference for conspecifics. • Variation in male mate choice may be a function of male age or quality. [ABSTRACT FROM AUTHOR]

Variation in risk-taking versus risk-averse behaviour can become a target of natural and/or sexual selection. However, the link between animal personality and mate choice—as a major component of sexual selection—remains understudied. We asked (1) whether females and males of the livebearing fish Poecilia mexicana prefer risk-taking mating partners (directional mating preference), (2) or if their preferences are dependent on the choosing individual's own personality type (assortative mating). We characterized each individual for its risk-taking behaviour, assessed as time to emerge from shelter and enter an unknown area. In dichotomous association preference tests, we offered two potential mating partners that differed in risk-taking behaviour but were matched for other phenotypic traits (body size, shape, and colouration). Females, but not males, exhibited a strong directional preference for risk-taking over risk-averse mating partners. At the same time, the strength of females' preferences correlated positively with their own risk-taking scores. Our study is the first to demonstrate that an overall preference for risk-taking mating partners does not preclude effects of choosing individuals' own personality type on (subtle) individual variation in mating preferences. More generally, two different preferences functions appear to interact to determine the outcome of individual mate choice decisions. [ABSTRACT FROM AUTHOR]

Reinforcement occurs when selection against hybrid offspring strengthens behavioral isolation between parental species and may be an important factor in speciation. Theoretical models and experimental evidence indicate that both female and male preferences can be strengthened upon secondary contact via reinforcement. However, the question remains whether this process is more likely to affect the preferences of one sex or the other. Males of polygynous species are often predicted to exhibit weaker preferences than females, potentially limiting the ability for reinforcement to shape male preferences. Yet, in darters (Percidae: Etheostoma), male preference for conspecific mates appears to arise before female preferences during the early stages of allopatric speciation, and research suggests that male, but not female, preferences become reinforced upon secondary contact. In the current study, we aimed to determine whether the geographically widespread darter species Etheostoma zonale exhibits a signature of reinforcement, by comparing the strength of preference for conspecific mates between populations that are sympatric and allopatric with respect to a close congener, E. barrenense. We examined the strength of preference for conspecifics for males and females separately to determine whether the preferences of one or both sexes have been strengthened by reinforcement. Our results show that both sexes of E. zonale from sympatric populations exhibit stronger conspecific preferences than E. zonale from allopatric populations, but that female preferences appear to be more strongly reinforced than male preferences. Results therefore suggest that reinforcement of female preferences may promote behavioral isolation upon secondary contact, even in a genus that is characterized by pervasive male mate choice. [ABSTRACT FROM AUTHOR]

Mating generally occurs with adult females, which undergo a suite of changes in morphology, physiology and behaviour during maturation. In the brown widow spider, Latrodectus geometricus , however, males can mate with immature females during a short period before they moult to the adult stage. Mating with immature females seems beneficial for males, because they are not at risk of being cannibalized, whereas cannibalism inevitably occurs in matings with adult females. We conducted choice experiments to elucidate male preference, courtship and mating behaviour with immature and adult females of different ages. We controlled for age of the females' webs to provide males with potential web-borne attractants of similar age. We tested whether males distinguish immature females that are ready to mate (late subadult stage) from adult females and from immature females that do not mate (early subadults), and we examined male response to young versus old adult females. Males approached and mated with adult females more frequently than late subadult females, but there were no differences in the frequencies of approach to early and late subadults or to adult females of different ages. Once on the web, however, males attempted to mate with the late subadults. We suggest that web-borne volatile cues, typical of adult females, may be reduced or lacking in late subadult females, yet less volatile cues may indicate receptivity. • Mating with immature females is an alternative tactic for brown widow males. • Adult females cannibalize mating males, but immature females do not. • Males approached and preferred to mate with adult females over receptive immatures. • Males did not show a preference for unreceptive versus late-stage receptive immatures. • Close-range cues in webs of immatures may indicate receptivity. [ABSTRACT FROM AUTHOR]

Sexual conflict generates a reproductive arms race that often involves behavioural adaptations of females to avoid male sexual coercion. Given the cognitive demands underlying behavioural adaptations, it is surprising that there has been little exploration of whether sexual conflict plays an important role in the evolution of female brain size. Here we used a livebearing fish, Gambusia holbrooki , from a natural population to examine the influence of female and male traits, including female brain size, on mating behaviours. Female body size was the best predictor of avoidance of attempted copulations, and the primary result suggesting an effect of female brain size indicated that females with smaller, not larger, brains displayed greater avoidance. Male coloration (silver or melanic) and female approaches to males were the primary determinants of interactions between the sexes. Melanic males directed more attention to females than did silver males. The positive association between female and male attention highlights the intriguing possibility that females may exert more control on male mating behaviour than previously acknowledged in this species. Overall, our results indicate that female brain size may have little impact on reducing male sexual coercion. Additional studies across taxonomic groups are needed to understand the generality of this pattern. • Rates of male attention to females correlate with rates of female approach to males. • Longer male genitalia lead to increased coercion only with large-brained females. • Female body size best explains avoidance of male copulation attempts. • Smaller brains are better at avoiding copulations from males with longer genitalia. [ABSTRACT FROM AUTHOR]

Species of flies in the genus Drosophila differ dramatically in their preferences for mates, but little is known about the genetic or neurological underpinnings of this evolution. Recent advances have been made to our understanding of one case: pheromone preference evolution between the species D. melanogaster and D. simulans. Males of both species are very sensitive to the pheromone 7,11-HD that is present only on the cuticle of female D. melanogaster. In one species this cue activates courtship, and in the other it represses it. This change in valence was recently shown to result from the modification of central processing neurons, rather than changes in peripherally expressed receptors, but nothing is known about the genetic changes that are responsible. In the current study, we show that a 1.35 Mb locus on the X chromosome has a major effect on male 7,11-HD preference. Unfortunately, when this locus is divided, the effect is largely lost. We instead attempt to filter the 159 genes within this region using our newfound understanding of the neuronal underpinnings of this phenotype to identify and test candidate genes. We present the results of these tests, and discuss the difficulty of identifying the genetic architecture of behavioral traits and the potential of connecting these genetic changes to the neuronal modifications that elicit different behaviors. [ABSTRACT FROM AUTHOR]

In many animals, females prefer large males to small males, which allow large males to be choosier than small males when selecting a mate. We investigated the courtship intensity of small‐ and large‐sized male fiddler crabs (Austruca perplexa) by examining their claw‐waving rates (waves/min) towards small‐ and large‐sized females. We found that large males showed a greater preference for large females by producing more waves/min towards them, whereas small males did not show any apparent preference for either large or small females. Moreover, the waving rate of large males was positively correlated with female size, but there was no correlation between waving rate and female size in small males. These results indicate that large males in a population become choosier and show strong mate choice, which is most likely due to their greater preference among females. [ABSTRACT FROM AUTHOR]

Classical sexual selection theory predicts that males should mate eagerly, yet blue monkey males often reject females' sexual invitations. We evaluated how males' responses to female solicitations related to female characteristics, number of males and conceptive females present, and the male's recent copulations. Using 12 years of data from a wild population, we found that males accepted only 20% of female solicitations. Odds of acceptance (copulation) increased for conceptive females, for females with whom the male copulated recently, and when fewer males were present. Odds of accepting nulliparous females decreased when more conceptive females were available, consistent with market models. Male responses did not relate to female rank or matings with other females the same day. When males responded negatively, nulliparous females were especially likely to receive aggression vs. mere refusal. Overall, males' decisions to mate with willing females depended both on female characteristics, especially fertility, and on social context. [ABSTRACT FROM AUTHOR]

Mate choice that is based on behavioural traits is a common feature in the animal kingdom. Using the Trinidadian guppy, a species with mutual mate choice, we investigated whether males use female swimming activity—a behavioural trait known to differ consistently among individuals in many species—as a trait relevant for their mate choice. In the first experiment, we assessed male and female activity in an open field test alone (two repeated measures) and afterwards in heterosexual pairs (two repeated measures). In these pairs, we simultaneously assessed males’ mating efforts by counting the number of sexual behaviours (courtship displays and copulations). Male and female guppies showed consistent individual differences in their swimming activity when tested both alone and in a pair, and these differences were maintained across both test situations. When controlling for male swimming behaviour and both male and female body size, males performed more courtship displays towards females with higher swimming activity. In a second experiment, we tested for a directional male preference for swimming activity by presenting males video animations of low- and high-active females in a dichotomous choice test. In congruence with experiment 1, we found males to spend significantly more time in association with the high-active female stimulus. Both experiments thus point towards a directional male preference for higher activity levels in females. We discuss the adaptive significance of this preference as activity patterns might indicate individual female quality, health or reproductive state while, mechanistically, females that are more active might be more detectable to males as well.

Because sexual selection typically acts on males, the evolution of conspicuous ornamentation in females has been insufficiently studied. Genetic correlation between the sexes and sexual or social selection on females have been proposed to explain female ornamentation, but they cannot fully explain certain patterns observed in nature such as female ornamentation in non-territorial, promiscuous species. The species recognition hypothesis, which postulates that ornamentation is adaptive because it prevents maladaptive hybridization, might plausibly explain female ornamentation. We examined this in two sympatric, non-territorial, promiscuous fish species, Tribolodon hakonensis (TH) and Tribolodon sachalinensis (TS), in which both sexes display species-specific conspicuous coloration in the breeding season. We conducted experiments on visual mate choice of male TH for conspecific and heterospecific females, and compared their association times. TH spent more time near conspecifics, indicating that they used visual cues to recognize them. Because the females of the two species presented to the males did not differ in body size, shape or behavior, male preference for conspecifics was probably based on female nuptial coloration. These results suggest that female ornamentation may evolve or be maintained not only by sexual or social selection within a species but also by interspecific interactions (e.g., hybridization). [ABSTRACT FROM AUTHOR]