Biology of Chelinidea vittiger1 with Notes on Its Host-Plant Relationships and Value in Biological Weed Control 2

Abstract

The biology of Chelinidea vittiger Uhler, a coreid that figured in the biological control of prickly pear cacti ( Opuntia spp.; Cactaceae) in Australia and California was studied on Opuntia vaseyi (Coulter) Britton and Rose under controlled conditions in the insectary and in the interior valleys of southern California during 1968–69. C. vittiger is univoltine in southern California. Eggs hatched in an average of 13 days. The 1st–5th nymphal stadia lasted an average of 9,8,14, 17, and 25 days, respectively. Instars 1–3 fed gregariously and externally on young pads and fruit; late-stage nymphs and adults were much less gregarious and fed mainly on older pads. In nature, females remained sexually immature through late summer and fall. Overwintering occurred as adults. Some females apparently mated prior to overwintering. Ovigenesis occurred during the period of winter rainfall. Males were polygamous; females, polyandrous. Females produced an average of 51±10 eggs in 9±2 clusters, 5.4±0.4 eggs/cluster, in 35±6 days. The sex ratio was 1:1. New records for natural enemies of C. vittiger include predation on nymphs and adults by the spiders Peucetia viridens Hentz (Oxyopidae) and Latrodectus mactans F. (Theridiidae), respectively, and egg parasitism by Ooencyrtus johnsoni Howard (Encyrtidae). The failure of C. vittiger to migrate to uninfested host-plants if its food sources were destroyed by competing phytophages, was an important factor limiting its effectiveness as a biological control agent in southern California, as in Australia.