Only Females Oviposit: Chemical Discrimination of Adult Stink Bug Sex by the Egg Parasitoid Trissolcus japonicus

Egg parasitoids foraging for suitable hosts scattered in the environment rely mainly on chemical cues. Elucidating ecology of natural enemies is important development effective and successful strategies conservation biological control. In this context, host cuticular hydrocarbons, which are exploited by several species egg as contact kairomones, could be used to retain them providing information about presence sex adults target species: because only females lay eggs that can subsequently utilized parasitoid reproduction. However, basis discrimination not well understood. We carried out behavioral bioassays investigate role played cues left brown marmorated stink bug, Halyomorpha halys Stål, searching behavior adult Trissolcus japonicus (Ashmead). A first set showed spent more time exploring patches contaminated with chemicals associated H. compared males. Similar responses were displayed T. when hexane extracts tested suggesting non-polar compounds involved discrimination. GC-MS analysis revealed quantitative differences two sexes, 1-hexadecene (more abundant males) being most component determining these differences. Hexane blended synthetic significantly reduced wasps’ arrestment crude extracts.