Natural Biological Control of Ascia monuste by the Social Wasp Polybia ignobilis (Hymenoptera: Vespidae)

摘要

Predatory wasps are among the main components of food chains within ecosystems. Social wasp Polybia ignobilis (Haliday) (Hymenoptera: Vespidae) is found in South America and Ascia monuste orseis (Godart) (Lepidoptera: Pieridae) is an important Brassica pest in the Americas. Although the importance of predatory Vespidae is acknowledged, little is known about their activity as agents of biological control of insects. For this reason, this research aimed to study the natural biological control of A. monuste caterpillars by P. ignobilis and focused on the importance of P. ignobilis as a predator of A. monuste caterpillars. It also investigated the influence of weather on P. ignobilis foraging activity and the mechanisms that govern its predatory behavior. The main predator of A. monuste caterpillars was social wasp P. ignobilis, which predated caterpillars from the second to the fifth instar. More intense predatory activity by P. ignobilis occurred in periods of higher temperature (up to 29 deg C) andmaximum sunlight (around 5:30 h after sunrise). P. ignobilis foraging was not observed when rain or strong winds occurred. Predation of A. monuste caterpillars by P. ignobilis is complex and comprises three behavioral mechanisms.