Field observations of dispersion, mating and development of Amorbus obscuricornis (Westwood) (Hemiptera: Coreidae)

Aspects of the behaviour and development of Amorbus obscuricornis were observed in the field during spring and summer 1994/1995 at a site in southern Tasmania. Nymphs of A. obscuricornis remained predominantly on host plants on which they were initially observed for much of their development. Some movements between hosts occurred with migrating nymphs ranging in age from second to fourth instar. Most adults observed for the first time on hosts were males, a number of which were later recorded with females. Males were observed to have longer host residence times (7-56 days) than females ( < 7 days). Complete nymphal development was roughly estimated to take considerably fewer degree-days under fluctuating field temperatures than at constant temperature. This suggested that other mechanisms (e.g. basking) may significantly influence nymphal growth and development.