ADAPTIVE SUPERPARASITISM IN SOLITARY PARASITOIDS - MARKING OF PARASITIZED HOSTS IN RELATION TO THE PAY-OFF FROM SUPERPARASITISM

1. The pay-off from an egg laid in a parasitized host is an important parameter in models on adaptive superparasitism in solitary insect par asitoids. 2. For Leptopilina heterotoma, a parasitoid of larval Drosop hila, the pay-off from a second egg laid in a host is 0.43 offspring w hen the interval between the two ovipositions is less than 3 h. For lo nger intervals, this pay-off decreases to almost zero for an interval of 24 h. 3. When a female encountering a parasitized host is able to e stimate the interval since the first oviposition, it is expected that she will take this into account in her host selection decisions. This is, however, not in the direct interest of the female that lays the fi rst egg, and marks the host. 4. We studied whether superparasitism in hosts containing a young egg is more common than in hosts containing a n older egg, when searching in a patch containing once-parasitized and unparasitized hosts. 5. The acceptance/encounter ratio of parasitized hosts increased for intervals longer than 6 h, as predicted when the interests of the marking female and the longevity of the mark are take n into account. 6. Superparasitism occurred more often when parasitoid s had previously searched a host patch 7 days before the experiment co mpared to when parasitoids had searched a patch 1 day before, a phenom enon predicted by dynamic optimal diet models.