Sensory exploitation and sexual conflict

Abstract

Much of the literature on male-female coevolution concerns the processes by which male traits and female preferences for these can coevolve and be maintained by selection. There has been less explicit focus on the origin of male traits and female preferences. Here, I argue that it is important to distinguish origin from subsequent coevolution and that insights into the origin can help us appreciate the relative roles of various coevolutionary processes for the evolution of diversity in sexual dimorphism. I delineate four distinct scenarios for the origin of male traits and female preferences that build on past contributions, two of which are based on pre-existing variation in quality indicators among males and two on exploitation of pre-existing sensory biases among females. Recent empirical research, and theoretical models, suggest that origin by sensory exploitation has been widespread. I argue that this points to a key, but perhaps transient, role for sexually antagonistic coevolution (SAC) in the subsequent evolutionary elaboration of sexual traits, because (i) sensory exploitation is often likely to be initially costly for individuals of the exploited sex and (ii) the subsequent evolution of resistance to sensory exploitation should often be associated with costs due to selective constraints. A review of a few case studies is used to illustrate these points. Empirical data directly relevant to the costs of being sensory exploited and the costs of evolving resistance is largely lacking, and I stress that such data would help determining the general importance of sexual conflict and SAC for the evolution of sexual dimorphism.

Female cooperation in plug formation in a spider: effects of male copulatory courtship

“…The payoffs to female L. mariana from biasing plug formation are not known, so this difference between SAC and CFC cannot be evaluated confidently. However, one version of SAC, which emphasizes physical coercion of the female by the male (Alexander et al 1997;Arnqvist andRowe 2002a, 2002b), seems unlikely to apply in L. mariana because neither the pushes with the male's front legs nor the short insertions of his genitalia physically coerce the female. In addition, females showed no sign of resistance to these male behavior patterns, despite the fact that they can easily interrupt undesired coercion by breaking away from males at any time during copulation or by pushing the male's palp away from the epigynum with their tarsi (Eberhard and Huber 1998;Mendez 2004).…”

“…In addition, females showed no sign of resistance to these male behavior patterns, despite the fact that they can easily interrupt undesired coercion by breaking away from males at any time during copulation or by pushing the male's palp away from the epigynum with their tarsi (Eberhard and Huber 1998;Mendez 2004). A sensory trap version of SAC (Arnqvist 2006), which supposes that female cooperation with the male is not in her own reproductive best interests, but persists because the male uses a sensory trap, also seems unlikely (though it cannot be eliminated) because it depends on females having been unable to free themselves from these traps (Eberhard 2009). For instance, a female change in response threshold or context-specific changes in female responsiveness could free the female from maladaptive oversensitivity to male stimulation.…”

Sensory Exploitation: Underestimated in the Evolution of Art As Once in Sexual Selection Theory?

“…Recent empirical research, and theoretical models, suggest that origin by SE has been widespread (Rodriguez and Snedden, 2004;Arnqvist, 2006). Arnqvist (2006) distinguishes two classes of origins of sensory biases that -as we will show in the next section -are also useful when considering the evolution of art.…”

“…Arnqvist (2006) distinguishes two classes of origins of sensory biases that -as we will show in the next section -are also useful when considering the evolution of art. First, females are adapted to respond in particular ways to a range of stimuli in order to, for example, successfully find food, avoid to become food for predators and breed at optimal rates, times and places.…”

“…Whenever studying a biological trait within the darwinian framework it is important to distinguish between the selective forces that led to its origin, its evolution and the processes that maintain it (Fisher, 1930). The origin of mating biases and displays are relatively hard to explain with the indirect-benefit model (Arnqvist, 2006). SE, however, may provide the initial 'nudge' often required to initiate choice-display coevolution Enquist 1995, Payne andPagel 2000).…”