DEVELOPMENT AND DIAPAUSE INPLEOLOPHUS BASIZONUS(HYMENOPTERA: ICHNEUMONIDAE)

Abstract

The upper limit for continuous development ofPleolophus basizonuslies between 25° and 30 °C since all stages develop at the former temperature and larval mortality is complete at the latter temperature. The lower limit lies between 5.5° and 10 °C, since an eonymphal diapause occurs at 5.5 °C. Between these extremes, diapause incidence varies inversely with temperature. The photoperiod experience of the parent has no effect on diapause in the progeny when the latter are reared at 15° and 18 °C, but there is an inverse relation between parental photoperiod experience and progeny diapause incidence at 10 °C. Although larvae and pupae also survive 3 months at 2 °C, most individuals probably overwinter in eonymphal diapause and their diapause requirements are fulfilled in 3 weeks at 2 °C. The incidence and rate of post-diapause development is directly related to temperature.