Meeting Abstract
Sex-specific selection pressures can generate different phenotypic optima for males and females in response to changing environments (sex differences in phenotypic plasticity). However, there is growing evidence that the ways in which parental environments alter offspring phenotypes (transgenerational plasticity) can also depend on sex. Sex-specific transgenerational plasticity is potentially of great evolutionary significance, as it is a mechanism by which potentially adaptive traits can persist selectively across generations via only daughters or sons. In previous work, I found that there were sex-specific sperm-mediated paternal effects in response to predation risk in threespined sticklebacks (Gasterosteus aculeatus). Here, I explore whether these sex-specific patterns might have evolved during the stickleback radiation. I compared replicate populations of ancestral (marine) and derived (freshwater) sticklebacks that were reared in a common garden. There was population-level variation in the direction of sperm-mediated paternal effects, and evidence for parallel evolution of sex-specific paternal effects during the stickleback radiation. In ancestral populations, sons and daughters responded similarly to paternal cues of predation risk, but in derived populations, sons and daughters responded differently. These phenotypic differences emerged well before offspring were reproductively mature, suggesting that these differences organize in early development. These results suggest that current work seeking to understand the evolution of transgenerational plasticity needs to also consider the conditions which favor the evolution of sex-specific transgenerational plasticity.
