The Role of Phenotypic Plasticity in Moderating Evolutionary Conflict

Abstract

Evolutionary conflicts arise when the fitness interests of interacting individuals differ. Well-known examples include sexual conflict between males and females and antagonistic coevolution between hosts and parasites. A common feature of such conflicts is that compensating evolutionary change in each of the parties can lead to little overt change in the interaction itself. As a result, evolutionary conflict is expected to persist even if the evolutionary dynamic between the parties reaches an equilibrium. In these cases, it is of interest to know whether certain kinds of interactions are expected to lead to greater or lesser evolutionary conflict at such evolutionary stalemates. Here we present a theoretical analysis showing that when one of the interacting parties can respond to the other through adaptive phenotypic plasticity, evolutionary conflict is reduced. Paradoxically, however, it is the party that does not express adaptive plasticity that experiences less conflict. Conflict for the party displaying adaptive plasticity can increase or decrease, depending on the situation.

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.…”

Genomics of Developmental Plasticity in Animals

“…Sasabe et al, 2007; Greenwood et al, 2011; Martins et al, 2014). Progress also includes studies that explore the role of environmental conditions as instructive agents that can affect the production, more than just the frequency, of phenotypic variants (Przybylo et al, 2000; Chakir et al, 2002; Gilbert and Epel, 2009; Torres-Dowdall et al, 2012; Day and McLeod, 2018; Fraimout et al, 2018; Sentis et al, 2018). This environmental regulation of phenotype expression, by which a genotype can produce different phenotypes depending on the external conditions experienced, is called phenotypic plasticity.…”

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).…”