Female plasticity tends to reduce sexual conflict

Abstract

Sexual conflict is the divergence of evolutionary interests between the sexes. A neglected aspect of sexual conflict theory is that the conflict often occurs within the female's body, which can lead to a power asymmetry between the sexes. In particular, the female may often be able to respond flexibly to the actions of the male, and so exhibits plasticity. Here, we consider the implications of female plasticity, and find that it tends to result in lower levels of sexual conflict. We then relate our results to a comparison of pre- versus post-copulatory sexual conflict, and we also show that this asymmetry between males and females reduces the likelihood of runaway selection, preventing co-evolutionary arms races. Finally, we discuss our results in the context of the evolution of adaptive harm and sexual conflict when there are direct benefits.

Sexual selection, phenotypic plasticity and female reproductive output

“…There is, however, a glimmer of hope. Recent theoretical models of sexual conflict over mating [162,163], offspring sex ratio adjustment based on sire attractiveness [60,173], and whether plastic maternal effects are more likely than plastic responses by offspring to generate adaptive outcomes [174] all show that there is the potential to make predictions about the extent to which different forms of phenotypic plasticity in sexually selected and allied traits facilitate adaptive evolution. The challenge now is to produce models that explicitly incorporate phenotypic plasticity, in order to ask questions about the role of sexual selection in facilitating population persistence in the face of rapid environmental change (see [175]).…”

“…An illustrative case in which females are the plastic party is post-copulatory sexual conflict, where males commit to a strategy by transferring seminal fluid proteins (SFPs) that females then respond to plastically. The general finding is that plasticity, compared with neither party showing plasticity, always reduces the conflict load of the non-plastic party, but that of the other party can either increase or decrease [162,163]. The intuitive reason is as follows.…”

“…We consider both. First, recent models examine in detail how plasticity affects sexually antagonistic selection [162,163]. Specifically, they ask how it affects the conflict load (fitness reduction compared with a hypothetical bestcase scenario) of individuals involved in pairwise interactions, when each party controls an antagonistic trait that decreases the other party's fitness.…”

Plasticity in male mating behavior modulates female life history in fruit flies

“…). Recent theoretical work, however, predicts that phenotypic plasticity in sexually antagonistic traits can either strengthen or weaken the intensity of sexual conflict (McLeod and Day ; Day and McLeod ). In the past few years, several studies have highlighted the importance of considering these socioecological effects when quantifying the intensity of sexual conflict (Perry and Rowe ).…”

“…Although the studies that have explored the relationship between mating system dynamics and male harm are critical for our understanding of the expression of male-induced harm and their consequences for female fitness, they were typically conducted in uniform environments, leaving out the important roles of variation in social and ecological factors (Arbuthnott et al 2014). Recent theoretical work, however, predicts that phenotypic plasticity in sexually antagonistic traits can either strengthen or weaken the intensity of sexual conflict (McLeod and Day 2017;Day and McLeod 2018). In the past few years, several studies have highlighted the importance of considering these socioecological effects when quantifying the intensity of sexual conflict (Perry and Rowe 2018).…”