Endosymbiont diversity and evolution across the weevil tree of life

Abstract

As early as the time of Paul Buchner, a pioneer of endosymbionts research, it was shown that weevils host diverse bacterial endosymbionts, probably only second to the hemipteran insects. To date, there is no taxonomically broad survey of endosymbionts in weevils, which preclude any systematic understanding of the diversity and evolution of endosymbionts in this large group of insects, which comprise nearly 7% of described diversity of all insects. We gathered the largest known taxonomic sample of weevils representing four families and 17 subfamilies to perform a study of weevil endosymbionts. We found that the diversity of endosymbionts is exceedingly high, with as many as 44 distinct kinds of endosymbionts detected. We recovered an ancient origin of association of Nardonella with weevils, dating back to 124 MYA. We found repeated losses of this endosymbionts, but also cophylogeny with weevils. We also investigated patterns of coexistence and coexclusion.