PHOTOPERIODISM IN THE DEVELOPMENT OF THE EUROPEAN PINE SAWFLY, NEODIPRION SERTIFER (GEOFF.)

Abstract

Photoperiods of 0 to 24 hours at 21 °C did not influence the length of the larval developmental period of N. sertifer or the weight of larvae at cocoon spinning. Upon incubation of cocoons in darkness, most of the larvae from 4- to 15-hour photoperiods metamorphosed without an intervening prepupal diapause, and emerged as adults 27 to 35 days after cocoon spinning. Individuals from the 0-, 20-, and 24-hour photoperiods underwent a prepupal diapause of 2 to 3 weeks before morphogenesis, and emerged as adults 44 to 55 days after cocooning. The transition from diapause to non-diapause is induced by a photoperiod of about 16 hours.