Effects of Hunger on Mate-choice Copying in the Guppy

A meta-analysis of factors influencing the strength of mate-choice copying in animals

Mate-choice copying is a form of social learning in which an individual’s choice of mate is influenced by the apparent choices of other individuals of the same sex and has been observed in more than 20 species across a broad taxonomic range. Though fitness benefits of copying have proven difficult to measure, theory suggests that copying should not be beneficial for all species or contexts. However, the factors influencing the evolution and expression of copying have proven difficult to resolve. We systematically searched the literature for studies of mate-choice copying in nonhuman animals and, then, performed a phylogenetically controlled meta-analysis to explore which factors influence the expression of copying across species. Across 58 published studies in 23 species, we find strong evidence that animals copy the mate choice of others. The strength of copying was significantly influenced by taxonomic group; however, sample size limitations mean it is difficult to draw firm conclusions regarding copying in mammals and arthropods. The strength of copying was also influenced by experimental design: copying was stronger when choosers were tested before and after witnessing a conspecific’s mate choice compared to when choosers with social information were compared to choosers without. Importantly, we did not detect any difference in the strength of copying between males and females or in relation to the rate of multiple mating. Our search also highlights that more empirical work is needed to investigate copying in a broader range of species, especially those with differing mating systems and levels of reproductive investment.

A conceptual review of mate choice: stochastic demography, within-sex phenotypic plasticity, and individual flexibility

Mate choice hypotheses usually focus on trait variation of chosen individuals. Recently, mate choice studies have increasingly attended to the environmental circumstances affecting variation in choosers' behavior and choosers' traits. We reviewed the literature on phenotypic plasticity in mate choice with the goal of exploring whether phenotypic plasticity can be interpreted as individual flexibility in the context of the switch point theorem, SPT (Gowaty and Hubbell 2009). We found >3000 studies; 198 were empirical studies of within‐sex phenotypic plasticity, and sixteen showed no evidence of mate choice plasticity. Most studies reported changes from choosy to indiscriminate behavior of subjects. Investigators attributed changes to one or more causes including operational sex ratio, adult sex ratio, potential reproductive rate, predation risk, disease risk, chooser's mating experience, chooser's age, chooser's condition, or chooser's resources. The studies together indicate that “choosiness” of potential mates is environmentally and socially labile, that is, induced – not fixed – in “the choosy sex” with results consistent with choosers' intrinsic characteristics or their ecological circumstances mattering more to mate choice than the traits of potential mates. We show that plasticity‐associated variables factor into the simpler SPT variables. We propose that it is time to complete the move from questions about within‐sex plasticity in the choosy sex to between‐ and within‐individual flexibility in reproductive decision‐making of both sexes simultaneously. Currently, unanswered empirical questions are about the force of alternative constraints and opportunities as inducers of individual flexibility in reproductive decision‐making, and the ecological, social, and developmental sources of similarities and differences between individuals. To make progress, we need studies (1) of simultaneous and symmetric attention to individual mate preferences and subsequent behavior in both sexes, (2) controlled for within‐individual variation in choice behavior as demography changes, and which (3) report effects on fitness from movement of individual's switch points.

Culture and courtship in vertebrates: a review of social learning and transmission of courtship systems and mating patterns

Female and male animals often choose mates based upon the complementarity of their courtship behaviours and preferences. The importance of this fact on the evolutionary dynamics of populations has long been appreciated. What has not been appreciated is the role that social learning might play in the transmission of systems of courtship behaviour across generations. This paper addresses the social transmission of courtship behavioural traditions in vertebrates. It discusses views of culture in the context of behavioural signals and preferences in courtship. It then reviews empirical evidence for culture-like processes affecting courtship behaviour, focusing on studies of song learning in passerine birds and work on social learning of mating preferences. The paper concludes with potential future directions for research on social traditions in systems of courtship behaviour, including determining mechanisms of transmission, genetic and non-social environmental effects, and selective factors influencing the stability of behavioural traditions over time. By integrating proximate and ultimate questions for the transmission of courtship systems, this work would increase our understanding of the ways individual development, cultural processes, and population evolution influence, and are in turn influenced by, one another.

Evidence of social effects on mate choice in vertebrates

Study of determinants of mate selection by animals has a long history in evolutionary biology and behavioural ecology. However, only during the past decade have investigators begun to conduct experiments exploring the various ways in which observation of the behaviour of others might influence mate selection. Here, we review both field and laboratory studies of behavioural processes that underlie non-independence in mate choice, discussing both direct and indirect social influences on mate selection. We focus on laboratory studies in which guppies and Japanese quail, species that have received greatest attention from investigators, have served as subjects. Although much is now known about how public information can affect mate selection in controlled environments, there are still significant gaps in our knowledge of whether and how such information contributes to mate selections by members of free-living populations.