Curves as traits: genetic and environmental variation in mate preference functions

Abstract

Study of the genetic and developmental architecture of mate preferences lags behind the study of sexual ornaments. This is in part because of the challenges involved in describing mate preferences, which are expressed as a function of variation in ornaments. We used the function-valued approach to test for genetic and environmental components of variation in female mate preferences in Enchenopa treehoppers (Hemiptera: Membracidae). These insects communicate with plant-borne vibrational signals, and offer a case study of speciation involving sexual selection and environmental change. We focused on female preferences for male signal frequency, the most divergent signal trait in Enchenopa. Obtaining complete, individuallevel descriptions of mate preferences in a full-sib, split-family rearing experiment, we document substantial genetic variation in mate preference functions. Focusing on traits describing variation in the shape of the preference functions, we further document considerable broad-sense heritability and evidence of weak genotype 9 environment interaction in most traits. Against the background of recent and rapid divergence in Enchenopa, these results indicate potent mechanisms that maintain variation and sustain the involvement of mate preferences in sexual selection.

Genetic variation in social influence on mate preferences

“…Thus, any one female genotype may favour different male phenotypes (and genotypes) according to variation in the social environment, thereby promoting the maintenance of genetic variation in male mating signals. In addition, recent work in Enchenopa has demonstrated direct genetic variation in mate preferences [40], social influence on mate preferences [34,35,40] and genetic variation in this influence [this study]. In concert with previous theoretical and empirical work highlighting genetic components of variation in both sides of social interactions [14,20,23,41], genetic variation within populations may be sustained by the interplay between how plastic individuals are due to social interactions and how much influence social neighbours can exert on individual plasticity.…”

Genetic Variation and Covariation in Male Attractiveness and Female Mating Preferences inDrosophila melanogaster

“…Numerous empirical studies have addressed various aspects of ornament-preference coevolution (Bakker 1993; Wilkinson and Reillo 1994; Blows 1999; Gray and Cade 1999; Brooks and Endler 2001; Iyengar et al 2002; Arnqvist and Kirkpatrick 2005; Qvarnström et al 2006; Shaw and Lesnick 2009; Hohenlohe and Arnold 2010; Wiley and Shaw 2010; Wiley et al 2012), but we still appear to be far from a consensus regarding the relative importance of various models of preference evolution. A major barrier to progress in this area stems from the problems associated with studying the genetic basis of preferences (Rodriguez et al 2013), which tend to be complex and can only be quantified from large, labor-intensive studies (Wagner 1998; Chenoweth and Blows 2006; Jones and Ratterman 2009). Nevertheless, quantification of the genetic basis of preferences is a key requirement to test predictions of sexual selection theory because genetic correlations between ornaments contributing to attractiveness and behavioral phenotypes leading to mate choice play a central role in the most influential models of preference evolution (Arnold 1983; Kirkpatrick 1987; Heisler 1994; Mead and Arnold 2004).…”

“…Although models usually describe mating preferences using a single variable for the sake of mathematical tractability, real mate choice is composed of multiple components, and probably cannot be fully described so simply (Brooks and Endler 2001; Rodriguez et al 2013). Preferences can be visualized as a function with a mating response on the y -axis and ornament values that contribute to attractiveness on the x -axis (Figure 1).…”

“…Finally, if the preference function has an intermediate peak, then each individual female may have a “peak preference,” an ornament value to which she responds most readily. In principle, each female could have a different preference function, so females may show variation in responsiveness, choosiness, and peak preference (Figure 1) (Rowland et al 1995; Gray and Cade 1999; Murphy and Gerhardt 2000; Brooks and Endler 2001; Reinhold et al 2002; Bailey 2008; Rodriguez et al 2013). It is also important to realize that although choosiness could be critically important in either model of preference functions, the most convincing empirical demonstrations of intersexual genetic correlations between mating preferences and sexually selected traits have focused on peak preference rather than choosiness (Wilkinson and Reillo 1994; Shaw and Lesnick 2009; Wiley and Shaw 2010; Wiley et al 2012).…”

Mating Is a Give-and-Take of Influence and Communication Between the Sexes

“…For males, it seems straightforward to posit two traits: a display plus the ability to sense and react to feedback from the female. For females, it is similarly straightforward to posit two traits: a mate preference function (Ritchie 1996;Rodríguez et al , 2013b and the behavior that expresses the mate preference and provides feedback to the male. Reality may be more complex than this, of course, but this scenario serves to highlight a series of potential outcomes.…”