Celebration of Scholarship and Creative Activity 2023
The scarab genus Osmoderma (Coleoptera: Scarabaeidae) includes several large species called hermit beetles that develop inside the decaying wood of hardwood trees. This genus has been studied extensively in Europe, where the species O. eremita is critically endangered, and males have been found to produce the attractive pheromone (R)-γ-decalactone. However, hermit beetles have been researched minimally in the US, resulting in a large gap in our knowledge of the North American species. Here, we identify the sex pheromone of the North American O. eremicola to also be γ-decalactone. Field trials were completed using traps baited with synthetic γ-decalactone at nine sites in east-central Wisconsin, during which we captured 9 males and 32 females. Captured males of O. eremicola also produced the pheromone in laboratory assays as measured by gas chromatography. Furthermore, our traps captured 7 females of the congener O. scabra, and 162 females of the predatory click beetle Elater abruptus (Coleoptera: Elateridae). We hypothesize that both species are eavesdropping on the pheromone of O. eremicola to locate appropriate habitat for their own offspring. Further research will be needed to determine the role of γ-decalactone in forested environments and how it mediates ecological interactions.