Data from: Sexual selection and population spatial structure interact to shape sex-specific evolutionary responses in physiology

Different selection pressures acting on females and males arising from
sexual selection and sexual conflict may lead to sex-specific phenotypic
expression of physiological traits. Importantly, sexual selection is
affected by ecological and demographic factors. We explored whether
population spatial structure modulates the effect of sexual selection on
male and female standard metabolic rates and oxidative stress. For this
purpose, we used selection lines of the seed beetle Callosobruchus
maculatus subjected to divergent evolutionary regimes in the intensity of
sexual selection (high vs. low, in polygamous vs. enforced monogamous
populations, respectively) and the presence of metapopulation structure
(absent vs. present). We found that the evolutionary treatments impacted
physiological traits in a complex way. While in the selection regimes
simulating metapopulation structure (i.e., divided populations) both sexes
had similar metabolic rates, in undivided (unstructured) populations males
had lower rates than females. Males from polygamous and undivided
populations showed the lowest levels of antioxidant enzymes quantified as
SOD, resulting in strong sexual dimorphism in SOD levels in this selection
regime. The oxidative damage to lipids measured as TBARS levels, instead,
were highest for both males and females from monogamous and undivided
populations. On the whole, our results reveal two key insights. First,
physiological traits evolve differently in females and males in response
to sexual selection intensity and population spatial structure. Second,
such sex-specific physiological responses are linked to selective
pressures acting mostly on males. We highlight the importance of
considering ecological and demographic factors when evaluating whether
sexual selection drives sex-specific trait
evolution.