Fungal community of mycetangia in the ship-timber beetle Elateroides dermestoides (Coleoptera: Lymexylidae) in Japan

Ship-timber beetles (Coleoptera: Lymexylidae) are associated with wood-inhabiting fungi. The female adults of the genus Elateroides possess fungus-carrying organs (so-called mycetangia) at the ovipositor and deposit fungal symbionts of the genus Alloascoidea onto wood during oviposition. The larvae grow by feeding on the fungi proliferating on the walls of tunnels that the larvae made in wood. Thus, in the fungus-growing mutualism practiced by Elateroides species, it has been considered that the beetles’ partners are Alloascoidea fungi. However, to date, lymexylid-associated fungal communities have been poorly documented. Here, I report that E. dermestoides originating from Japan harbored at least nine fungal species. When microbial isolation was conducted from mycetangia of five female adults of E. dermestoides , colonies of filamentous fungi and yeasts were recovered. DNA analyses revealed that they were Candida boleticola , Cosmospora berkeleyana , Kuraishia floccosa , and undescribed fungi of the genera Alloascoidea , Ambrosiozyma , Ca. mesenterica -related Candida , Ca. palmyrensis -related Candida , Cyberlindnera , and Ogataea . Of those, Alloascoidea sp., Cyberlindnera sp., and Ogataea sp. were frequently isolated (80–100%), while the others showed low isolation rates, suggesting that these three fungal species are closely associated with E. dermestoides . The findings strongly suggest that multiple fungal species including Alloascoidea are involved in the life history of lymexylids.