| Popis: |
Intralocus conflict has been well documented between the sexes, but much less is known about the potential for this genetic conflict in other polymorphisms, such as alternative reproductive tactics. Here we investigate two of three criteria necessary for demonstrating intralocus tactical conflict: the ARTs have different phenotypic optima for a shared trait, and one or both ARTs are not at their phenotypic optima for a shared trait. We address these two criteria in Xiphophorus multilineatus, a live-bearing freshwater fish that has two male alternative reproductive tactics, a behaviorally fixed courter male and a behaviorally plastic sneaker male that switches between courtship and force-copulatory behavior. We used measures of reproductive success from a wild population to estimate selection gradients on three tactically dimorphic traits involved in sexual selection: body size, body shape, and sword length. We present evidence that both body size and sword length are experiencing tactically antagonistic selection, providing evidence for both criteria. Additionally, selection on body shape in sneaker males appears to be buffered due to behavioral plasticity. Our study provides novel insight from a wild population into the role that intralocus tactical conflict can play in constraining ARTs from reaching their respective phenotypic optima despite tactical dimorphism. |
