Abstract

Climate change is altering the relative timing of species interactions by shifting when species appear in a community and by accelerating developmental rates. However, phenological shifts may be mediated through community contexts, such as intraspecific competition and alternative resource species, which can prolong the otherwise shortened windows of availability. Using a combination of laboratory experiments and dynamic simulations, we quantified how the effects of phenological shifts in Drosophila-parasitoid interactions differed with concurrent changes in temperature, intraspecific competition, and the presence of alternative host species. We found that community context, particularly the presence of alternative host species, supported interaction persistence across a wider range of phenological shifts than pairwise interactions. Parasitism rates declined under warming, which limited the ability of community contexts to manage mismatched interactions. These results demonstrate that ongoing declines in insect diversity may exacerbate the effects of phenological shifts in ecological communities under future global warming temperatures.