Abstract
Preliminary experiments to determine the environmental factors responsible for the wing form and the related sensitivity of stages were conducted in the oriental chinch bug, Cavelerius saccharivorus. High temperature, long photoperiod, and crowding in the nymphal stage stimulated the appearance of macropters. Conversely, low temperature, short photoperiod, and isolation favoured for the appearance of branchypters. Until the early 5th instar, the nymphal stage was sensitive to temperature and/or photoperiod, whereas later instars(4th to 5th) were more sensitive to nymphal crowding than earlier ones (1st to 3rd). The envirinmental control of wing form determination on this species is discussed in relation to the life cycle and seasonal fluctuation in number of the field population.
