Yeast associated with flower longicorn beetle Leptura ochraceofasciata (Cerambycidae: Lepturinae), with implication for its function in symbiosis

Abstract

Wood is difficult for most animals to digest due to large amounts of indigestible polymers, but some wood-feeding insects are considered to be able to utilize it as food with the aid of microbial symbionts. Most members of flower longicorn beetles (Coleoptera: Cerambycidae: Lepturinae) feed on nectar and pollen of flowers as adults and wood as larvae. In some lepturines, associations with yeasts are known: female adults possess fungus-storing organs (termed mycetangia) at ovipositors, and larvae also possess such organs (termed mycetomes) in their midguts to carry the associated yeasts. Despite the high diversity of Lepturinae in the world, lepturine-yeast associations, such as the consistency of associated yeasts among the beetle’s developmental stages and ecological function of yeast symbionts, have been poorly documented. Here, we investigated the yeast symbiont of the Japanese common lepturine Leptura ochraceofasciata. X-ray computed microtomography revealed that a pair of tube-like, S-shaped mycetangia was located at the basal part of the ovipositor and that a muscle bundle joined the apex of the mycetangium to spiculum ventrale of sternum VIII. All female adults harbored only one yeast species, Scheffersomyces insectosa, in the mycetangia. All larvae harbored S. insectosa exclusively in the mycetomes. Scheffersomyces insectosa was also recovered from surfaces of eggs. Scheffersomyces insectosa assimilated wood-associated sugars including xylose, cellobiose, and xylan in culture. These results suggest the intimate association between L. ochraceofasciata and S. insectosa: S. insectosa is transmitted from the mother to offspring during oviposition and may be related to larval growth in wood.

The Eurasian spruce bark beetle Ips typographus shapes the microbial communities of its offspring and the gallery environment

“…This extracellular symbiont improves the beetle's diet by supplying its host with pectinolytic enzymes (Salem et al, 2017). Other coleopterans rely on the transmission of yeast symbionts to ensure the survival of their offspring in nutrient-poor diets, such as the longicorn beetle Leptura ochraceofasciata (Kishigami et al, 2023), and the lizard beetle Doubledaya bucculenta (Toki et al, 2012). In all of the above, the female harbors a single bacterial or fungal taxon in a specialized organ and inoculates the egg during oviposition.…”

Insects Associated with the European Mistletoe (Viscum album) in Western Ukraine: a Pilot Study

“…However, our observations indicate that the most likely mechanism of V. album infection is the transfer of spores and mycelia of S. visci by the vectors, which are the longhorn beetles (Cerambycidae), fungus weevils (Anthribidae), true weevils (Curculionidae) etc. The most of these beetles have special internal and external organs for the accumulation, transfer and distribution of spores and mycelium, called mycangia (Bartnik et al, 2001;Grebennikov & Leschen, 2010;Sasakura, 2022;Kishigami et al, 2023). Females in typical cases bring fungi culture during oviposition, which contributes to the formation of both the environment for the development of larvae and the dispersing of fungi (Kishigami et al, 2023).…”

“…The most of these beetles have special internal and external organs for the accumulation, transfer and distribution of spores and mycelium, called mycangia (Bartnik et al, 2001;Grebennikov & Leschen, 2010;Sasakura, 2022;Kishigami et al, 2023). Females in typical cases bring fungi culture during oviposition, which contributes to the formation of both the environment for the development of larvae and the dispersing of fungi (Kishigami et al, 2023). It is clear that S. visci spreads by this mechanism.…”