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 vital rates vary across species, facilitating modeling and analysis of high-diversity assemblages. We assessed the larval survival and competency dynamics of four previously unstudied coral species at current and warmed temperatures, and combined it with data for three other species to assess how well egg size predicts the sensitivity to warming of mortality and the minimum time to competency, both determinants of larval dispersal. 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.