Inter- and intra-specific competition in Bethylid wasps

Intraspecific and interspecific competition is poorly studied in Bethylid wasps, a very complex family of parasitoids that includes genus with different degrees of sociality. For examples, Goniozus species are sub-social and aggressively excludes conspecific females from the brood, showing an increasing competition when multiple foundress are present on the same victim. Conversely, Sclerodermus species are quasi-social parasitoids, with foundress that share the oviposition site and take care of the brood all together. However, until now the information on the competition among Sclerodermus sp. foundress is poor. A major degree of competition can occur in interspecific rivalry. In this case the competition can be influenced by the prior ownership of the host as well as by the parasitoid and host size, the biology of the parasitoid, the oviposition time, etc. No study about interspecific competition in Sclerodermus sp. is present in literature so far. The present study aims at evaluating both inter- and intra-specific competition in Sclerodermus brevicornis. Tests have been set up to evaluate 1) the behavior of S. brevicornis in case of overexploitation of the host, forcing intraspecific competition with increasing number of foundress on the same victim (10-55 foundress/victim); 2) the effect of the degree of kinship in intraspecific competition (none, two siblings, all siblings) on different behavioral traits (cooperation, ability to parasitize, number of eggs, number of offspring., etc.); 3) interspecific competition occurring in the case of an encounter on the same host between a more aggressive species (Goniozus legneri) and a more cooperative one (S. brevicornis).