External gall traits influence insect community composition, diversity, and parasitoid intraspecies genetic divergence in two sister Aciurina (Tephritidae) species

Galls induced by insects are highly diverse in external morphology. Though it is believed that many morphological characters have evolved as parasitoid defense, comparisons of closely related galling taxa with divergent gall morphologies are required to assign differences in gall-associated arthropod community to difference in external gall traits. Over two seasons, galls of two sister galling Aciurina (Tephritidae) species with distinct gall forms were collected across New Mexico and reared to document the arthropod communities of each gall morphology. Members of the respective communities, including an inquiline weevil, parasitoid wasps (Ichneumonoidea, Chalcidoidea), and a hyper-galling Cecidomyiidae midge with its own suite of parasitoid wasps (Platygastroidea, Chalcidoidea), are documented herein, and the community compositions associated with each gall morphology are compared. Beta diversity analyses show significant clustering of communities by morphology. Aciurina trixa galls across sites have a higher rate of parasitism, and are more diverse, rich, and even in parasitoid community. Primary parasitoid success is strongly correlated to smaller gall size in both morphologies, while hypergaller parasitoids are strongly correlated to larger gall size in A. bigeloviae galls. Furthermore, phylogenetic and morphological analyses of one parasitoid associated with both Aciurina species, Eurytoma sp., show consistent divergence which suggests intraspecies specialization to gall morphology. Together, these results 1) describe robust communities of A. trixa and A. bigeloviae, 2) connect gall size and parasitoid success, and 3) provide evidence that the communities of each of the two Aciurina gall morphologies differ on both the community and species level in New Mexico.