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

<i>Nasonia</i> is a species complex of four parasitoid wasps. <i>N. vitripennis</i> is cosmopolitan, while the other three species are micro-sympatric with it. This distribution can select distinct species-specific mate recognition capabilities. However, whether <i>Nasonia</i> males can distinguish between hosts with conspecific females and those with heterospecific females is not known. Therefore, we test this hypothesis in a cafeteria-based choice assay and show that <i>N. vitripennis</i> males can distinguish hosts with conspecific wasps against those parasitized by <i>N. giraulti</i> and <i>N. oneida</i>, exhibiting longer search time and distance traversed with faster search speed. We also found that <i>N. longicornis</i> males can distinguish hosts with conspecific wasps, but only against the hosts parasitized by <i>N. oneida</i>. We further investigated the pairwise differences in the cuticular hydrocarbon (CHC) profiles of the parasitized hosts and adult female wasps. The results reveal that males show this ability only when the compounds responsible for differences in adult female CHC profiles are 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.