Odors from corn plants infested with the larvae of the noctuid herbivore Mythimna separata attract tachinid fly, Exorista japonica, females. We investigated the effects of elapsed time on the attraction of E. japonica to plants after host larvae were removed. The behavior of the flies within 5 min from introduction was observed in a wind tunnel. The percentage of flies attracted to the plants remained high (70%) for 5 h and decreased gradually after 24 h. The percentage of flies attracted to continuously damaged plants remained high for 5 days. In contrast, the percentage of flies reaching artificially damaged corn plants was high (85%) when tested soon after damage but decreased to 40% 1 h after damage. We also examined whether undamaged leaves from a damaged plant attracted tachinid flies. Undamaged leaves were not attractive when all other leaves on the same plant were damaged, even if damaged for several hours. In addition, the undamaged part of damaged leaves was not attractive. These results indicate that volatiles that attract E. japonica are only released from the damaged parts of leaves and these volatiles gradually decrease as the damaged plant ages.

-Phytoremediation has been proposed for the elimination of toxic metals in soil, yet little attention was 12given to the performance of insects that feed on contaminant-tolerant plants. We tested the performance of two

Odors from corn plants infested with the larvae of the noctuid herbivore Mythimna separata (Walker) attract tachinid fly, Exorista japonica Townsend, females; and odors from corn plants artificially damaged also attract this fly. We investigated the responses of flies to herbivoreinfested, artificially damaged, and undamaged plants before and after arrival at the target plants to measure timing of the behavioral sequence. The behavior of the flies for 10 min after takeoff from a release point was observed in a wind-tunnel bioassay. The percentage of flies attracted to the plants was higher in infested and artificially damaged plants than in undamaged plants. Latency before takeoff was longer in undamaged plants, and time from takeoff to arrival at the plant was also longer in undamaged plants. Moreover, flies stayed longer on infested and artificially damaged plants. Flies walked longer on infested plants than on artificially damaged and undamaged plants. In this paper, we summarize the behavioral data and discuss the host-searching behavior of E. japonica females.