Mating Behavior of Jute Hairy Caterpillar, Diacrisia obliqua WALKER (Lepidoptera : Arctiidae) I : Precopulatory Behavior Patterns in Adults

Abstract

Experiments were carried out in the laboratory to determine the patterns of adult emergence and mating behavior of jute hairy caterpillar moths. Moths were used from larval rearing on leaves of ground nuts, cowpea, field pea, brinjal, cabbage and artificial diet. The emergence of male moths usually began late in the afternoon and that of female ones began at dusk. Moths after emergence were paired in screen cages before dusk. The female moths more than 12 hr old used to release a brownish fluid from the adbominal tip and assumed typical calling position while clinging to the side walls of the screen cages, 1 or 2 hr before sunset by frequent movement of antennae and wing raising. The assumption of calling position was followed by rhythmical protraction and retraction of the apical abdominal segments 7, 8 and 9. The male moths that emerged in the evening or before midnight most frequently responded to this calling posture of the female moths by stop-gap movement and wing vibrations. The calling behavior ceased at mignight and again commenced 2 or 3 hours before sunrise. The time of mating coincided very closely with that of their emergence. Two peakes of mating were recorded at 1830 and 0400 hr respectively. More than 80% of the pairs copulated before midnight. Maximum mating was observed in the 1st-day-adults. Mating activity ceased after the 2nd-day of emergence and sunrise in both sexes.