Host preference and mortality caused by the parasitoid Sclerodermus guani on different cerambycid species

Parasitoids of wood borers and bark beetles rarely encounter different host species simultaneously in nature, so whether they exhibit any preferences for particular species, and the relative suitability of different host species is unclear. Sclerodermus guani (Hymenoptera: Bethylidae) is an ectoparasitoid of cerambycid larvae and has also been reported from multiple host species. In this study we used S. guani as a model parasitoid to evaluate preferences for different host species. Moreover, we determined how levels of intraspecific interaction amongst S. guani adults affect host species preference, and subsequent mortality of those different hosts. S. guani adults display high levels of preference for particular hosts and cause rates of non-reproductive mortality of Aromia bungii (Coleoptera: Cerambycidae) and Monochamus alternatus (Cerambycidae) larvae that are higher than the reproductivity mortality of both hosts. Under different parasitoid densities interaction, S. guani always preferred A. bungii and Monochamus saltuarius (Cerambycidae) and varied in its responses to Thyestilla gebleri (Cerambycidae) and M. alternatus. In addition, the mortalities of single T. gebleri, A. bungii or M. saltuarius larvae caused by the parasitoids (1-3 individuals) were all 100%. These results can help us to better understand S. guani host choice behavior and its biological control potential.