Infanticide in a Dryinid Parasitoid, Haplogonatopus atratus

When a parasitized host is superparasitized, the second comer—an immature parasitoid originating from the second oviposition—is usually handicapped relative to the first comer in the competition for the host. In Haplogonatopus atratus, however, the survival rate of second comers is frequently higher than that of first comers. Infanticide is assumed to be responsible for this phenomenon. The present report reveals that, when the female wasp of H. atratus superparasitizes, she examines several membranes between the host's abdominal terga with her stinger before laying a supernumerary egg and that, when she locates the first comer, she pierces it with her stinger to kill it. Moreover, once she catches a host she performs infanticide irrespective of whether the host is self- or conspecifically parasitized.