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ARS Home » Northeast Area » Newark, Delaware » Beneficial Insects Introduction Research Unit » Research » Publications at this Location » Publication #101458
Title: DETERMINING PARASITOID SPECIES COMPOSITION IN A HOST POPULATION: A NEW MOLECULAR APPROACH

Author
item TILMON, KELLEY - CORNELL UNIVERSITY
item DANFORTH, BRYAN - CORNELL UNIVERSITY
item Day, William
item HOFFMAN, MICHAEL - CORNELL UNIVERSITY

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/1999
Publication Date: 5/10/2000
Citation: Tilmon, K., Danforth, B., Day, W.H., Hoffman, M. 2000. Determining parasitoid species composition in a host population: a new molecular approach. Annals of the Entomological Society of America. 93(3)640-647

Interpretive Summary: Most species of closely-related parasites have very similar, or apparently identical, larvae. Therefore, although the dissection method can accurately and quickly measure parasite effectiveness, the species of parasites often cannot be determined. The parasitized hosts must then be reared for weeks or months, until the emergence of adult parasites that can nbe identified. The DNA method that we developed will accurately identify parasite larvae in a few days, saving much time, and it also avoids the low efficiency of the rearing method that results from parasite and host mortality.

Technical Abstract: Larvae of closely related parasite taxa often lack morphological differences that can be used to easily separate different species. Determining the parasite species present in a host population then requires rearing to obtain adult parasites, often a time-consuming process. To monitor field parasitism rates by several species of Peristenus wasps (Hymenoptera: Braconidae) that are natural enemies of Lygus (Heteroptera: Miridae), we have developed a two-step molecular approach. PCR with wasp- targeting primers is performed on DNA extracted from a Lygus nymph and the parasite larvae (if any) therein. A positive reaction indicates parasite presence. Next, a restriction digest on the PCR product will indicate which parasite species is present among known alternatives, and a diagnosis is achieved in days rather than weeks or months.