Sexually antagonistic co‐evolution: a model and an empirical test

Abstract

Models reveal that sexually antagonistic co-evolution exaggerates female resistance and male persistence traits. Here we adapt an established model by including directional sexual selection acting against persistence. We find similar equilibria to previous models showing that sexually antagonistic co-evolution can be limited by counteracting sexual, as well as, natural selection. We tested the model using empirical data for the seaweed fly, Coelopa ursina, in which body size acts as a persistence and a resistance trait. Our model can generate continuous co-evolutionary cycles and stable equilibria, however, all simulations using empirically derived parameter estimates reach stable equilibria. Thus, stable equilibria might be more common in nature than continuous co-evolutionary cycles, suggesting that sexual conflict is unlikely to promote speciation. The model predicts male biased sexual size dimorphism for C. ursina, comparable with empirically observed values. Male persistence is shown to be more sensitive than female resistance to changes in model parameters

Laboratory adaptation reduces female mating resistance in the sweet potato weevil

“…This causes sexual conflict, with the sexual traits favored in one sex potentially being costly to members of the opposite sex. Therefore, sexually antagonistic co-evolution might arise between males and females (Holland & Rice, 1998), leading to runaway exaggeration of male persistence and female resistance traits (evolutionary arms race), cycles of trait exaggeration, and stable equilibria (Holland & Rice, 1998;Rowe et al, 2005;Hoyle & Gilburn, 2010;Kazanclo glu & Alonzo, 2012). Some researchers have shown that female resistance traits to male mating attempts result in antagonistic sexual selection for persistence traits in the males of species such as the fruit fly Drosophila melanogaster Meigen (Rice, 1996), the water strider Gerris incognitus Drake & Hottes (Perry & Rowe, 2012), and two species of diving beetles, Dytiscus lapponicus Gyllenhal, and Graphoderus zonatus (Hoppe) (Green et al, 2013).…”

Sexual Conflict and Antagonistic Coevolution Across Water Strider Populations

“…The sexes are expected to have conflicting evolutionary interests within nearly all sexually reproducing species (Arnqvist and Rowe 2005). Under some conditions, this conflict is expected to generate sexually antagonistic coevolution (SAC), which may produce continual exaggeration of male persistence and female resistance traits (an arms race), cycles of trait exaggeration, or gradual trait de‐escalation and retreat (Parker 1979; Holland and Rice 1998; Gavrilets et al 2001; Rowe et al 2005; Hoyle and Gilburn 2010).…”

Sexual conflicts along gradients of density and predation risk: insights from an egg-trading fish

“…Conflicts over mating rates and mate choice have given rise to a spectacular array of manipulative secondary sexual characters and harmful mating tactics in both gonochores and hermaphrodites (Parker 1979;Arnqvist and Rowe 2005;Michiels and Koene 2006). Yet recent studies suggest that stable equilibria and palliative adaptations are just as likely to evolve in response to sexual conflicts, especially when the costs of harmful traits are considered (see Lessells 2006;Hoyle and Gilburn 2010). Parceling in the eggtrading fishes may be such an example; the costs imposed on individuals that escalate within-pair conflict by producing an increasing number of parcels may exceed the benefits gained in extra-pair matings.…”