CLUTCH SIZE AND OVIPOSITION SITE CHARACTERISTICS OF A NOCTURNAL AFRICAN SILK MOTH IMBRASIA-BELINA (LEPIDOPTERA, SATURNIIDAE)

Oviposition site characteristics, clutch size, and hatching success we re studied in a population of nocturnal silk moths (Imbrasia belina We stwood) in arid northwestern Namibia. There was little evidence of ovi position site choice based on host-tree (Colophospermum mopane) charac teristics, although trees with eggs were closer to neighboring conspec ific trees and small (< 1 m) trees rarely received clutches. Clutch si ze and hatching success were positively correlated, but neither was in fluenced by any of the measured tree characteristics. Similarly, neith er clutch size nor hatching success was related to oviposition orienta tion on the leaf surface (i.e., inner or outer leaf surface). The appa rent lack of host discrimination in this species may be due to a serie s of ecological constraints, including limited nocturnal flight period s and an unusually short adult Lifespan.