Phenotypic plasticity in female mate choice behavior is mediated by an interaction of direct and indirect genetic effects in Drosophila melanogaster

Abstract

Female mate choice is a complex decision-making process that involves many context-dependent factors. In Drosophila melanogaster, a model species for the study of sexual selection, indirect genetic effects (IGEs) of general social interactions can influence female mate choice behaviors, but the potential impacts of IGEs associated with mating experiences are poorly understood. Here, we examined whether the IGEs associated with a previous mating experience had an effect on subsequent female mate choice behaviors and quantified the degree of additive genetic variation associated with this effect. Females from 21 different genetic backgrounds were housed with males from one of two distinct genetic backgrounds for either a short (3 hr) or long (48 hr) exposure period and their subsequent mate choice behaviors were scored. We found that the genetic identity of a previous mate significantly influenced a female's subsequent interest in males and preference of males. Additionally, a hemiclonal analysis revealed significant additive genetic variation associated with experience-dependent mate choice behaviors, indicating a genotype-by-environment interaction for both of these parameters. We discuss the significance of these results with regard to the evolution of plasticity in female mate choice behaviors and the maintenance of variation in harmful male traits.

Keywords: indirect genetic effects; mate choice; phenotypic plasticity; population genetics; sexual conflict; sexual selection.

Figure 1

Effect of previous mating experience and female genotype on female interest in associating with males in Drosophila melanogaster. The reaction norm plot in the center depicts the proportion of time each female hemiclone line spent over a subchamber containing a male over the entire duration of the assay across the two mating experience treatments, while the boxplots depict the distribution of data independent of hemiclonal background. The boxes contain the middle 50% of data (interquartile range, IQR), and the horizontal lines represent the medians. Values >±1.5× IQR are outliers and are represented by closed circles, and all other values that are not outliers are represented by the whiskers above and below each box

Figure 2

(a) Left effect of previous mating experience and female genotype on female preference in Drosophila melanogaster. The reaction norm plot in the center depicts the proportion of time each female hemiclone line spent with the high‐harm male over the total time she spent with males across the two mating experience treatments (degree of preference for high‐harm male), while the boxplots depict the distribution of data independent of hemiclonal background. The boxes contain the middle 50% of data (interquartile range, IQR), and the horizontal lines represent the medians. Values >±1.5× IQR are outliers and are represented by closed circles, and all other values that are not outliers are represented by the whiskers above and below each box. (b) Right scatterplot and regression line illustrating the negative relationship between the amount of time spent with the high‐harm male compared to females from each of 21 different hemiclone lines that had been previously exposed to either low‐harm males or high‐harm males