Development and reproduction of <i>Diadegma semiclausum</i> (Hymenoptera Ichneumonidae) on diamondback moth <i>Plutella xylostella</i> (Lepidotera Plutellidae)

Abstract

This study investigated the development emergence and mating of Diadegma semiclausum Hellen an important parasitoid of diamondback moth in the laboratory at 21 1C and 5060 RH with a photoperiod of 1212 h (lightdark) The parasitoids developmental period was significantly shorter and pupal weight significantly higher if their mothers parasitised the fourth instar larvae of DBM (P<001) The offspring sex ratio was strongly malebiased (<20) but no significant difference was detected between host instars Most adults emerged during the first few hours of the photophase and none emerged during the scotophase Mating had no effect on the longevity of both sexes but small females lived significantly longer than the larger ones (P<005) Male age and size had no effect on mating success whereas small females achieved higher mating success than large ones (P<005) The implication of this study in massrearing in the laboratory is discussed