Nasonia vitripennis males exhibit greater effort and competency in detecting hosts with conspecific females than other Nasonia males

Nasonia is a species complex of four parasitoid wasps. N. vitripennis is cosmopolitan, while the other three species are micro-sympatric with it. This distribution can select for distinct species-specific mate recognition capabilities. However, whether Nasonia males can identify hosts with conspecific females against hosts with heterospecific females is not known. Therefore, we tested this hypothesis in a cafeteria-based choice assay and show that N. vitripennis males can distinguish hosts with conspecific wasps against those parasitised by N. giraulti and N. oneida, exhibiting longer search time and distance traversed with faster search speed. We also found that N. longicornis males can distinguish hosts with conspecific wasps, but only against the hosts parasitised by N. oneida. We further investigated the pairwise differences in the cuticular hydrocarbon (CHC) profiles of the parasitised hosts and adult female wasps. The results reveal that the males show this ability only when the compounds responsible for differences in adult female CHC profiles were also the key differentiators of the host CHC profiles. The comparative mate searching behaviour of males of all reported species within a genus has rarely been studied. Therefore, this study makes a significant contribution to our understanding of interspecific variation of conspecific-mate searching behaviour.