PAYOFF FROM SELF AND CONSPECIFIC SUPERPARASITISM IN A DRYINID PARASITOID, HAPLOGONATOPUS-ATRATUS

Using Haplogonatopus atratus, a solitary parasitoid of the small brown planthopper, Laodelphax striatellus, we traced the development of the first- and second-laid eggs from oviposition to adult emergence, and revealed their survival rates, developmental periods, and adult head w idths in self and conspecific superparasitism. When the interval betwe en the first and second ovipositions was 1 h, the survival rate of the second comer was as high as the survival rate of the immature parasit oid in singly-parasitized hosts (60%), but the survival rate of the fi rst was less than 20%, With increasing oviposition interval, the survi val rate of the second decreased while that of the first increased. Co nsequently the survival rate of the first comer became similar to, or more than, that of the second for oviposition intervals of 1 day and o ver. For almost all intervals the survival rate of the first comer and that of the second were each higher in conspecific superparasitism th an in self superparasitism. As a result, in conspecific superparasitis m, the sum of survival rates of the first and second comers was higher than the survival rate of the parasitoid in single parasitism for mos t oviposition intervals; on the other hand, in self superparasitism th e sum was similar to or less than the survival rate in single parasiti sm. The developmental period for wasps from superparasitized hosts was similar to that for wasps from singly-parasitized hosts both when sup erparasitism was self and conspecific. However, the developmental peri od of the second comer was longer than that of the first for 8- and 12 -h intervals, while the reverse was true for almost all of the other i ntervals. As for the head width of emerged wasps, there was no differe nce between wasps from superparasitized hosts and wasps from singly-pa rasitized hosts for almost all oviposition intervals. The head width o f the second comer, however, was larger than that of the first for ovi position intervals of not more than 48 h in both self and conspecific superparasitism.