Received: 3 February 2020 | Revised: 10 August 2020 | Accepted: 18 August 2020 DOI: 10.1002/ece3.6930 ORIGINAL RESEARCH Immunogenetic and tolerance strategies against a novel parasitoid of wild field crickets Kristin L. Sikkink1 | Nathan W. Bailey2 | Marlene Zuk3 | Susan L. Balenger1 1Department of Biology, University of Mississippi, Oxford, MS, USA Abstract 2Centre for Biological Diversity, School Among the parasites of insects, endoparasitoids impose a costly challenge to host of Biology, University of St Andrews, St defenses because they use their host’s body for the development and maturation Andrews, UK 3Department of Ecology, Evolution, and of their eggs or larvae, and ultimately kill the host. Tachinid flies are highly special- Behavior, University of Minnesota-Twin ized acoustically orienting parasitoids, with first instar mobile larvae that burrow into Cities, St. Paul, MN, USA the host’s body to feed. We investigated the possibility that Teleogryllus oceanicus Correspondence field crickets employ postinfestation strategies to maximize survival when infested Susan L. Balenger, Department of Biology, University of Mississippi, Oxford, MS, USA. with the larvae of the parasitoid fly Ormia ochracea. Using crickets from the Hawaiian Email:
[email protected] Islands of Kauai, where the parasitoid is present, and crickets from the Cook Islands (Mangaia), where the parasitoid is absent, we evaluated fitness consequences of infestation by comparing feeding behavior, reproductive capacity, and survival of males experimentally infested with O. ochracea larvae. We also evaluated mecha- nisms underlying host responses by comparing gene expression in crickets infested with fly larvae for different lengths of time with that of uninfested control crickets. We observed weak population differences in fitness (spermatophore production) and survival (total survival time postinfestation).