Speaker
Description
Insect-microbe relationships are widespread, traversing a broad spectrum of reciprocal dependency, intimacy, duration, and cooperation. Many insects are only able to establish in their ecological niche because of bacterial partners. The false click beetles (Coleoptera, Throscidae) are a small, but globally distributed family that live in leaf litter and decaying wood and were previously reported to harbor intracellular symbionts in specialized bacteriomes. In this study, we investigated three of the four extant genera of Throscidae beetles for their symbiotic microbes, providing insights into host-symbiont interactions based on symbiont genomes and localization. The ancient Shikimatogenerans symbiont with a highly eroded genome was present in all examined taxa, probably supplying tyrosine precursors for cuticle biosynthesis as its only contribution to the host. Beyond this, several secondary symbionts from the Enterobacterales and Flavobacteriales with variable tissue tropism, genome sizes, and encoded capabilities were present, suggesting multiple symbiont acquisition events. Their inferred roles range from parasitic by manipulating host reproduction, to mutualistic, supplying amino acids and cofactors. Thus, beyond deepening our understanding of tyrosine-supplementing symbionts across a broad range of beetle families, the Throscidae provide insights into a dynamic evolutionary history with multiple co-occurring symbionts, expanding our view on multipartite symbiotic interactions in insects.
