Abstract
The mating behavior of wild melon flies, Dacus cucurbitae, was observed under field conditions. Males congregated and engaged in wing vibration in the late afternoon on non-host plants such as Bidens pilosa, Amaranthus lividus and Crassocephalum crepidioides, which populated over bordering cucurbit fields. Males defended their calling sites from other males through wing vibration, fighting or mounting. The rate of mating success per male in relation to female encounters was extremely low (1 : 61), suggesting that each female exerted "female choice." Judging from these results we conclude that males of the melon fly form leks.
