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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #126149
Title: FORAGING EFFICACY OF A LARVAL PARASITOID IN A COTTON PATCH: INFLUENCE OF CHEMICAL CUES AND LEARNING.

Author
item Olson, Dawn
item HODGES, T - GEORGIA SOUTHERN UNIV.
item Lewis, Wallace

Submitted to: Journal of Insect Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2003
Publication Date: 9/1/2003
Citation: Olson, D.M., Hodges, T.A., Lewis, W.J. 2003. Foraging efficacy of a larval parasitoid in a cotton patch: Influence of chemical cues and learning. Journal of Insect Behavior. 16(5):613-624.

Interpretive Summary: A huge challenge to many parasitoid insects is locating their hosts which may be concealed in nature. We know that parasitoids are attracted to chemicals emitted by plants that have been fed upon by their larval host, and that they are able to learn. It is generally believed that both of these attributes greatly enhances host location in the field. However, no studies have actually tested these ideas under field conditions. Here we directly observed and recorded the length of time that a parasitic wasp spent in various foraging behaviors in an arena with damaged and undamaged cotton plants simulating actual field conditions. We found that the parasitoids spent significantly more time hovering and searching damaged versus undamaged plants, and seldom landed on undamaged plants. Searching time significantly decreased with each success in parasitizing a host, although hovering time remained constant throughout the foraging bout. These results suggest that learning influenced searching but not hovering behavior and that increased host location rates were mainly due to learning associated with wasp searching behavior once they had landed at the infested site of an infested plant. We have demonstrated that the ability of parasitoids to exploit plant-related chemicals and their ability to learn both greatly enhances their ability to locate their hosts under field conditions.

Technical Abstract: We quantified the benefits of plant-related chemicals and learning on foraging efficacy of Microplitis croceipes under simulated field conditions after directly observing and recording time spent in various foraging behaviors by M. crociepes relative to 5 randomly placed and host-infested damaged cotton plants and 20 undamaged and non-infested plants. We found that females spent significantly more time hovering and searching near or on damaged versus undamaged plants. The collective time of all the behaviors observed within the patch (resting, preening, searching and hovering) showed a nonsignificant negative trend with successive host stings, suggesting only a slightly increased rate of host location through learning when all behaviors are considered. However, searching time was significantly and negatively correlated with successive host stings and hovering time remained constant throughout the foraging bout. These results suggest that learning influenced searching but not hovering behavior within this arena, and that chemical cues and learning greatly enhanced the host foraging efficacy of M. crociepes under simulated field conditions.