Payoff from Self and Conspecific Superparasitism in a Parasitoid, Haplogonatopus atratus (Hymenoptera: Dryinidae) : the Case of Third Instar Hosts(Behavior and Ecology)

Using a solitary parasitoid, Haplogonatopus atratus, and 3rd instar larvae of its host, we assessed the fitness payoff from self and conspecific superparasitism. Payoff for the first and second comers, i.e., offspring from the first and second ovipositions, respectively, was measured in terms of survival to wasp emergence, adult size, and developmental time. In most cases, the developmental time and adult size for both the first and second comers were similar to those for single parasitism. Offspring resulting from self and conspecific superparasitism had similar survival rates. The sum of survival rates of the first and second comers was slightly higher than the survival rate for single parasitism when the time interval between the first and second ovipositions was 1h. This suggests an advantage of self superparasitism over single parasitism, but the sum decreased with increasing oviposition intervals. The survival rate of the second comer in conspecific superparasitism was less than 15% below the survival rate for single parasitism (64.4%) for oviposition intervals of 48h or shorter, but the survival rate decreased with increasing oviposition intervals longer than 48h. This indicates that conspecific superparasitism is adaptive conditionally. Furthermore, the following two observations suggests that the superparasitizing female kills the first comer before laying an egg: (1) first comers were more likely to survive when the superparasitizing wasp did not completely inspect the host with her stinger; and (2) first comers died more frequently before the 3rd instar than in singly parasitized hosts.