Behavioural ecology of mango leaf webber, Orthaga exvinacea Hampson

Behavioural studies of mango leaf webber, Orthaga exvinacea were carried out both in the laboratory and field conditions, majorly focusing on neaonate larva, mating, oviposition and intra specific competition. The feeding behaviour of O. exvinacea was found to be gregarious i.e., a group of larvae coalesce together and scrape the chlorophyll content of young leaves. However, the later instars start feeding voraciously by making webs joining the adjacent leaves along with the shoots. The female moths laid eggs individually or in groups (8-14 eggs/cluster) on the lower surface of leaves near the midrib, while eggs were occasionally laid on the upper surface of the leaves during the early hours of photophase. Under field conditions, a series of observations revealed that the eggs were commonly laid in well-established older webs. During scotophase, several behavioural transitions in both male and female moths were observed while studying the mating behavior under laboratory conditions. Larval migration among the brood members of O. exvinacea was also noticed during the study.