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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #142940
Title: LEARNING OF HOST SEARCHING CUES BY THE LARVAL PARASITOID MICROPLITIS CROCEIPES.

Author
item TAKASU, KEIJI - KYUSHU UNIV/JAPAN
item Lewis, Wallace

Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2003
Publication Date: 9/1/2003
Citation: Takasu, K., Lewis, W.J. 2003. Learning of host searching cues by the larval parasitoid Microplitis croceipes. Entomologia Experimentalis et Applicata. 108:77-86.

Interpretive Summary: A better understanding and use of natural enemies of agricultural pests is important to developing effective alternatives to the economic costs and environmental hazards of conventional pesticides. ARS scientists at Tifton, GA, together with their cooperators, are studying how the parasitic wasp, Microplitis croceipes, a natural enemy of the bollworm/corn earworm, detects and tracks chemical cues to optimize their host/pest-finding efficiency. They showed that the proper combination of antennal and ovipositor contact with both the host and associated odors is important to the learning and persistency of learned responses to chemical cues. Stinging of the host with resulting ovipositor contact with hemolymph is vital for persistence of the learned information. This knowledge of the how parasitic wasps use learned cues to locate hosts is an important step in developing improved strategies for biologically-based pest management of agricultural crops.

Technical Abstract: Flight tunnel studies were conducted to determine effects of previous experiences on learning and retention of responses in the larval parasitoid, Microplitis croceipes. Various encounters with host and non-host products and odor associations evolving different antennal and ovipositor experiences were provided to the wasp prior to testing. Very high responses were obtained by females that had either antennated host frass or oviposited in a host in the presence of the test odor. Contact with non-hosts caused negative responses. The high responses persisted for 24 h only when subsequent oviposition involving contact with hemolymph of a host took place within 5 min after linking odor with host frass. These results indicate that antennal and ovipositor experiences with both hosts and odors affect learning and persistency of learned response to odors. These and related findings help understand the mechanisms governing the foraging behavior of parasitoids and ways to optimize their application in biological control of agricultural pests.