10.6084/m9.figshare.11282159.v1 Linyi Zhang Linyi Zhang Glen R. Hood Glen R. Hood James R. Ott James R. Ott Scott P. Egan Scott P. Egan Emergence time dataset from Temporal isolation between sympatric host plants cascades across multiple trophic levels of host-associated insects The Royal Society 2019 allochronic isolation gall wasp host-associated differentiation sequential divergence phenology 2019-11-27 12:59:31 Dataset https://rs.figshare.com/articles/dataset/Emergence_time_dataset_from_Temporal_isolation_between_sympatric_host_plants_cascades_across_multiple_trophic_levels_of_host-associated_insects/11282159 Phenological differences between host plants can promote temporal isolation among host-associated populations of insects with life cycles tightly coupled to plant phenology. Divergence in the timing of spring budbreak between two sympatric sister oak species has been shown to promote temporal isolation between host plants and their host-associated populations of a cynipid gall wasp. Here, we examined the generality of this mechanism by testing the hypothesis of cascading temporal isolation for five additional gall-formers and three natural enemy species associated with these same oak species. The timing of adult emergence from galls differed significantly between host-associated populations for all nine species and parallels the direction of the phenological differences between host plants. Differences in emergence timing can reduce gene flow between host-associated populations by diminishing mating opportunities and/or reducing the fitness of immigrants due to differences in the availability of ephemeral resources. Our study suggests that cascading temporal isolation could be a powerful ‘biodiversity generator’ across multiple trophic levels in tightly coupled plant–insect systems.