Developmental period and adult size of Haptoncus ocularis (Coleoptera: Nitidulidae) at four temperature conditions

Abstract

Haptoncus ocularis is a candidate pollinator of the subtropical orchard tree cherimoya (Annona cherimola). To collect basic information for the use of this species as a pollinator by mass rearing and releasing in greenhouses, the developmental period and attained adult size at constant temperatures of 15, 20, 25 and 30°C were investigated. The photoperiod was 16-h light/8-h dark at all temperatures. The developmental period was shorter at higher temperatures, except at 30°C, which lengthened pupation. Mortality from last instar larva to adult eclosion was higher at 15 and 30°C than at 20 and 25°C. The thermal threshold (developmental zero) ranged from 8.2 to 12.2°C for different developmental stages and sexes. The thermal constant (total effective temperature) of the period from egg to the next oviposition was ca. 284 degree-days. Both head width and right forewing length of the adults raised were largest at 20°C and second largest at 25°C. The maximum number of generations in a year was estimated to be nine in Wakayama, Japan.