1999 Volume 34 Issue 4 Pages 475-479
Diapause induction and termination in larvae of a phytophagous lady beetle, Epilachna admirabilis Crotch, were studied in the laboratory. The critical photoperiod was approximately 14.7 h. In photoperiodic transfer experiments between long, and short-daylengths at 24°C to estimate the beginning and end of diapause sensitivity, we estimated the time required for 50% diapause by probit analysis to be 2.1 days. The sensitive period began 6.3 days and ended 12.0 days after molting of 4th-stadium larvae. As their pupation starts mostly from 12 days after the 4th-stadium molt under conditions averting diapause caused by long daylength, larvae of this species are sensitive, and diapause ensues during a later stage of the 4th stadium. In relation to diapause termination, pupation was accelerated with increasing duration of cold storage (5°C). Larval diapause terminated without cold exposure in 33.2 days under long daylength and 90.6 days under short daylength. These results suggest that diapause termination and post diapause development are related to temperature, duration of cold storage, and photoperiod as a token stimulus.
