ENVIRONMENTAL CONTROL OF DIAPAUSE AND POSTDIAPAUSE DEVELOPMENT INTETRASTICHUS JULIS(HYMENOPTERA: EULOPHIDAE), A PARASITE OF THE CEREAL LEAF BEETLE,OULEMA MELANOPUS(COLEOPTERA: CHRYSOMELIDAE)

Publisher Website
Google Scholar
Abstract
MatureTelrastichus julis(Walker) larvae, which overwinter in the pupal cells of their dead cereal leaf beetle hosts, enter diapause in late summer. Diapause is maintained by warm conditions and short daylengths during late fall and early winter; it ends without a specific terminating stimulus. Subsequently the larvae remain in a state of postdiapause quiescence until soil temperatures rise above 9 °C, the theoretical threshold (t) for postdiapause development. Emergence of the central New York population occurs when the parasites have accumulated 162 degree days (D°) of heat above 9 °C. ThisKvalue is considerably lower than that previously reported for a population from Michigan.Our study provides the first experimental evidence that both temperature and photoperiod regulate the rate of diapause development in a parasitic insect.