Symbionts in -free cicadas and their implications for co-evolution between endosymbionts and host insects.

Obligate symbionts in sap-sucking hemipterans are harbored in either the same or different organs, which provide a unique perspective for uncovering complicated insect-microbe symbiosis. Here, we investigated the distribution of symbionts in adults of 10 -free cicada species of 2 tribes (Sonatini and Polyneurini) and the co-phylogeny between 65 cicada species and related symbionts ( and YLSs). We revealed that YLSs commonly colonize the bacteriome sheath besides the fat bodies in these two tribes, which is different with that in most other -free cicadas. Co-phylogeny analyses between cicadas and symbionts suggest that genetic variation of occurred in Sonatini and some other cicada lineages and more independent replacement events in the loss of /acquisition of YLS in Cicadidae. Our results provide new information on the complex relationships between auchenorrhynchans and related symbionts.