Sublethal Effects of Cypermethrin on Chemical Communication, Courtship, and Oviposition in the Cabbage Looper (Lepidoptera: Noctuidae)

Abstract

Sublethal doses of cypermethrin had multiple deleterious effects on reproductive activities in the cabbage looper, Trichoplusia ni (Hubner). Cypermethrin-treated female moths were less likely to show calling behavior than control moths. However, no differences were observed between treated and control females in the pheromone emission rates or pheromone blend ratios from forcibly extruded glands. Thus, those treated females that did call probably emitted sufficient pheromone to attract mates. Pheromone-mediated flight was reduced in males treated with cypermethrin, which would result in a reduction in successful mate location by affected males. In observations of courtship, treatment of males with cypermethrin reduced their mating success, but identical treatment of females had no effect. Results of this research are compared with previous studies of the effects of sublethal doses of chlordimeform and methoprene on reproductive events in T. ni.