Incidence and diversity of torix Rickettsia –Odonate symbioses. Rickettsia symbiont of odonate insects

In Odonates (dragonfly and damselfly) infection with Wolbachia – the symbiont that is estimated to infect 50% of terrestrial insects - has only recently been observed. Odonates are a diverse taxon with great importance as an indicator species to conservation. As known hosts of Wolbachia, it is likely that Odonates are also hosts of other symbiotic bacteria, like Torix group Rickettsia, which have been suggested as a relatively common symbiont of freshwater invertebrates. Of the 73 species that we screened using multilocus sequencing in this study, 10 (13.6%) were infected with Torix Rickettsia, and co-infection by different Torix Rickettsia was observed in some individuals. Use of Florescent In-situ Hybridisation (FISH) found bacteria in the oocytes of infected females, indicating the presence of vertical transmission for these symbionts. This is the first time that the presence of a symbiotic Rickettsia bacteria has been described in Odonates. The presence of symbionts in these species could potentially have implications for our ecological understanding of these organisms.