Culture-independent approach for endosymbiotic bacterial systematics in Pentatomidae

In the last decade, stink bugs haves been aim of extensive studies to elucidate the microbiota mainly associated within an important portion of their midgut, the gastric caecum. Great bacterial diversity has been found in this region from diverse stink bugs species and in some cases, the symbionts play an important role on the insect fitness. However, most of these symbionts are yet unculturable. Thus, we surveyed six species of pentatomid stink bugs - Pellaea stictica, Loxa deducta, Thyanta perditor, Piezodorus guildinii, Dichelops melacanthus and Edessa meditabunda (Hemiptera: Pentomidae) - using a culture-independent approach for a better understanding of the evolutionary relationship between the insects and their symbionts. All clones belong to Enterobacteriaceae family and although several RFLP pattern were found from each stink bugs species, they were usually clustered together. Exception was found for symbionts from T. perditor which were scattered along several phyletic branches. Furthermore, some clones formed new phyletic groups and at least for L. deducta, Pe. sticta and T. perditor, our data suggests a coevolutionary association with their caeca-symbionts. Finally, on the basis of molecular and phylogenetic data we proposed 3 Candidatus.