The Peculiarities of Diapause Induction by Photoperiod and Temperature in Trichogramma evanescens Westw. and T. chilonis Ishii (Hymenoptera, Trichogrammatidae) from the South of the Russian Far East

摘要

The induction of diapause in the populations of Trichogramma evanescens Westw. and T. chilonis Ishii from the south of Primorskii Territory in the Russian Far East was studied at the constant temperatures of 7, 8, 10, 15, 20, and 25°C. The parental generations developed at either 25° or 20°C and a day length of 16 or 10 hours. The maximum fraction of diapausing prepupae of T. evanescens (nearly 100 %) was observed at the temperatures of 8-10°C, that of T. chilonis only at 10°C, regardless of parental photoperiodic or thermal conditions. The influence of parental temperature and photoperiod on diapause of the progeny was found only in T. evanescens. In this species, after the parental generation had been kept under short-day conditions and a temperature of 25°C, the progeny showed higher incidence of prepupal diapause in the short-day line than in the long-day line at the temperatures of 7 and 15°C.