Predicting demography from species traits: larval development time and its sensitivity to warming depend on egg size in corals

In the absence of demographic data, readily measurable life history traits, like egg size, can be used to predict how demographic rates vary across species, facilitating modeling and analysis of high-diversity assemblages. We assessed the larval survival and competency acquisition dynamics, both determinants of larval dispersal, of four previously unstudied coral species at current and warmed temperatures. This dataset was combined with comparable data for three other coral species to assess how well egg size predicts larval mortality, the minimum time to competency and their sensitivity to warming. Minimum time to competency increased with egg size; moreover, warming-induced reductions in time to competency were greater for species with larger eggs. In contrast, mortality rate and its response to warming were both independent of egg size. These findings show how assemblage-level responses to environmental change can be inferred for diverse communities and indicate how warming-induced changes in larval biology may reshape reef coral metacommunities.