Abstract
Fertility of Achaearanea tepidariorum (C. L. Koch) that were fed mosquitoes chemosterilized by pupal exposure to thiotepa was significantly reduced. Mortality was excessive for spiders fed mosquitoes treated topically with thiotepa. Maximal weekly dosages, estimated by residue analysis, were 12 and 21 ng/male and female respectively for spiders fed mosquitoes treated as pupae and over 3 times greater for spiders fed mosquitoes treated topically as adults. The susceptibility of this predator to small chronic dosages of chemosterilant suggests that mass releases of chemosterilized insects are potentially hazardous to food chain components.