Max Planck Institute for Chemical Ecology Jena, Thuringen, Germany
Nutritional symbionts have been a major factor driving the evolution of insects and probably one factor underlying their remarkable radiation. Convergently evolved associations of various Coleoptera with bacterial symbionts supplementing precursors for the synthesis of their cuticular exoskeleton might have driven the evolutionary success of this order of insects. Bacteroidetes bacteria include a distinguished, ancient lineage that is only found in association with insects, including the obligate symbionts of Blattodea and Auchenorrhyncha. However, we recently also identified Bacteroidetes bacteria in association with multiple beetle families, including the Bostrichidae, Silvanidae and Throscidae. Across these families, we find highly specialized symbionts contributing precursors for the synthesis aromatic amino acids, but also alternating strains able to recycle nitrogen as well as some that are reminiscent of recently acquired symbionts or reproductive manipulators like Sodalis or Wolbachia. These insights expand our understanding of the evolution of this particular clade of symbionts as well as its potential origin, but also their herbivore hosts.
