Abstract
Two kinds of traps baited with cue-lure and naled, and with sliced pumpkin and naled respectively, were distributed in different habitats of the melon fly, Dacus cucurbitae, to investigate its diurnal pattern of attraction. When both kinds of traps were distributed in a bitter gourd field, the intermediate site, which was the transition area of vegetation from bitter gourd field to forest, and forest, attraction to cue-lure traps was observed in each of those sites. Many flies were attracted to pumpkin traps within the bitter gourd field and intermediate site, but only a few were attracted to the forest site. The total number of males caught in cue-lure traps was lower than that in pumpkin traps. Attraction to cue-lure traps was observed in the morning, whereas the attraction to pumpkin traps took place throughout the day time. The number of captured male flies in the pumpkin traps was higher than that in the cue-lure traps, and furthermore, a similar number of female flies was captured in the pumpkin traps. Most of these female flies were immature. Attraction of mature female flies occurred later in the day than that of the immatured ones, i.e., the number of captured mature flies increased in the afternoon or early evening. Percentage of female flies captured in pumpkin traps was higher in the bitter gourd field and intermediate site than in the forest. These results suggest that the number of flies caught in cue-lure traps varied temporally during the day time but did not vary with the trap sites. In contrast, the number of flies caught in the pumpkin traps did not vary temporally, but varied with the trap sites.
