Abai, MR

6th International Congress of DipterologyHost Habitat and Host Location Behavior in the tachinid Fly,Exorista japonicaKainoh, Y. (1), C. Tanaka (1), R. Ichiki (2), Y. Yamawaki (3) & S. Nakamura (2)(1) Doctoral Program of Biosphere Resource Science and Technology, Graduate Schoolof Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan(2) Japan International Research Center for Agricultural Sciences (JIRCAS), Ohwashi,Tsukuba, Ibaraki 305-8686, Japan(3) Department of Biology, Faculty of Science, Kyushu University, Fukuoka 812-8581,JapanWe demonstrated by a wind tunnel bioassay that the tachinid fly, Exoristajaponica, is attracted to corn plants damaged by the noctuid larva,Mythimna separata. Mated female flies oriented to damaged corn plants,but did not respond to undamaged corn plants. This orientation occurred tothe damaged plant itself, but not the host larva or larval frass. In order totest the effect of plant color, blue, green, yellow and red paper models wereplaced in front of damaged corn plants hidden with a mesh screen. Thelanding rate of flies was highest on green and lowest on red paper models.In addition, flies did not respond to the green model without a damagedplant or in the presence of a healthy plant. The behavior of flies tochemicals in the host frass were tested by placing a filter-paper patchtreated with the frass in a plastic cage. Flies stayed longer in a patch treatedwith host frass or host frass extracts than in untreated patches and thisresponse was dose-dependent. Responses were strongest to the methanolextract among several solvents. These experiments indicate that E.japonica females find the host habitat not only by long-range olfactorycues (damaged plant odor) but also visual cues (plant color), and once in ahost habitat they tended to stay longer in a patch with close-range olfactorycues (host frass). Finally, flies use visual cues to attack the host larvae.Key Words: Exorista japonica, Tachinidae, host location, host habitatlocation, wind tunnel127