Remodeling male coercion and the evolution of sexual autonomy by mate choice

Abstract

Models of sexual conflict over mating, including conflict over indirect benefits of mate choice, have generally presumed that female resistance to male coercion must involve direct confrontation, which can lead to sexually antagonistic coevolutionary arms-races. We built a quantitative model examining the largely ignored possibility that females may evolve new, additional mate preferences for new male traits that undermine male capacity to coerce. Thus, females may “remodel” the coercive capacity of the male phenotype in order to enhance their own sexual autonomy—a novel alternative mechanism by which females may avoid arms-races. We demonstrate that evolutionary “remodeling” is possible, in spite of costs to males, because females that prefer males with protective, autonomy-enhancing traits (traits correlated with lower coercion effectiveness) are likelier to gain indirect benefits of having attractive mates. Our analysis reveals new possibilities for the evolution of systems of sexual conflict over indirect benefits, showing that autonomy-enhancing male traits can act as a “public good,” benefiting all females regardless of mating preferences, leading to oscillatory dynamics; and that preferences for more protective male traits will often be favored relative to preferences for less protective traits, potentially leading to an evolutionary “snowball” of expanding sexual autonomy.

Opposites attract: Multiple evidence of sexual antagonistic coevolution driving extreme male-biased sexual size dimorphism inPanopeus meridionalis

“…Even in the scenario of overt sexual coercion, in the long run the females may benefit by passing increased survival, mating success, and fitness associated with dominant males to offspring, (the sexy sons or the good genes hypotheses) so that a submission can also be interpreted as part of the repertoire of behaviors available for female choice in this context (Snow et al, 2019;Snow & Prum, 2023). Accordingly, the fact that the experimentally mated females all had developing or ready to spawn ovaries (Fig.…”

“…Strictly, mating is considered coercive if it decreases female fitness (Clutton-Brock & Parker, 1995), something extremely hard to prove in natural conditions (De Lisle, 2019). A less strict definition, that sexual coercion occurs whenever there is '...(male) action biasing mating in a way that subverts an existing (female) mating preference…' (Snow & Prum, 2023), might be useful for distinguishing whether a given trait evolved in a scenario of sexual coercion. Even then, a conclusion may require the integration of multiple sources of evidence to assess whether a particular set of traits is consistent with what would be expected for an explicitly coercive mating system at play (Eberhard, 2002).…”

When less is more: coy display behaviours and the temporal dynamics of animal courtship

“…This third, most elaborate version of the threat reduction hypothesis has recently been explored using quantitative mathematical models by Snow & Prum [ 53 ]. Their proof-of-concept analysis suggests that, given a specific level of coercion, male traits that enhance female sexual autonomy—which they call ‘autonomy-enhancing’ traits—may indeed persist in the population as females experience indirect benefits from mating with more attractive males.…”

“…In summary, mate choice may act to maximize the sexual autonomy of choosers since those individuals that are better able to evaluate and freely select their mates benefit both directly and indirectly from reproducing with more attractive individuals [ 53 ]. Given the direct, often physical costs of sexual coercion, this prediction holds true for all relevant models of sexual selection (Fisherian runaway, indicator mechanisms, perceptual biases, and chase-away selection [ 56 ]).…”

“…2018–2019, personal observation). Threat reduction may therefore have less to do with evolutionary ‘remodelling’ [ 53 ] than simply reducing the risk that receivers terminate courtship because of a reflexive, pre-existing startle response. Also, rather than only being threatening, connoting a negative valence, vigorous courtship elements may have a positive, stimulating effect on receivers.…”