Reconsidering the ecological niche of Euceroptres (Hymenoptera: Figitidae) parasites of oak galls using dissection, micro-CT, and genetic barcoding

Monday, November 11, 2024

8:48 AM – 9:00 AM MST

Location: Phoenix Convention Center, 222 B, PCC

Presenting Author(s)

Guerin E. Brown (he/him/his)

Graduate Student
University of Iowa
Iowa City, Iowa

Co-Author(s)

AF

Andrew A. Forbes

University of Iowa
Iowa City, Iowa

Insect galls are atypical growths of plant tissue initiated by an ovipositing insect. The resulting structure functions as a larval nursery, providing necessary food and shelter for the insect offspring. Galls formed by wasps on oaks (Hymenoptera: Cynipidae) are frequently invaded by at least eleven genera of parasites that exploit the nutritive resource of either the gall or the larvae inside. These parasites may function as parasitoids, kleptoparasites, or hyperparasites which, respectively, feed either on the larva inside the gall, the gall tissue itself, or other parasites. However, for many North American oak-gall-associated genera, the dietary preference or ecological niche is unknown or poorly documented. Here we describe the ecology of oak gall parasites in the genus Euceroptres (Hymenoptera: Figitidae), long assumed to be kleptoparasites. We searched for changes to internal gall structural and physical interactions between larvae using dissections. We DNA barcoded interacting organisms using mtCOI. We scanned a subset of galls using microcomputed tomography (micro-CT) to assess the spatial orientation and size of internal regions of the gall where Euceroptres parasites were present. Unlike confirmed oak gall kleptoparasites that create separate chambers within the gall tissue, we find Euceroptres parasites exclusively in otherwise unaltered gall wasp chambers. This suggests that Euceroptres are either parasitizing or otherwise replacing the inducing gall wasp.