Calling behaviour of adult female Helicoverpa armigera (Hubner) (Lep., Noctuidae) of overwintering generation and effects of mating

The calling behaviour of overwintering generation females of Helicoverpa ar migera and the effects of mating were studied in the laboratory at 24 + 1 d egrees C and under reversed light-dark cycle (16 h light:8 h dark). Age had a significant influence on calling patterns. Based on calling age, mean nu mber of calling bouts and total calling length of virgin females increased significantly, and mean onset time of calling advanced significantly from c alling day 1 to subsequent calling days. Females of the overwintering gener ation exhibited more short bouts in calling, and some females that initiate d calling on a previous day did not call on subsequent days. Mating had no effect on the overall patterns, but did affect calling behaviour. Mated fem ales did not resume calling after mating during the same scotophase and, on the day following mating, mated females called less frequently and for a s horter duration, but thereafter increased to the same level of virgin femal es of the same calling age. Furthermore, as the moth aged, the percentage o f mated females calling was lower than that of virgin females.