Microbial assemblages within Philaenus spumarius and their possible role on insect´s reproduction

Microorganisms colonizing internal tissues of insects are known important players in the insect’s reproduction, nutrition, and fitness. Thus, a better knowledge and characterization of this microbial community can lead to their exploitation in the management of insect populations. Philaenus spumarius has been of interest in the recent years due to its confirmed ability of vectoring the plant pathogen Xylella fastidiosa. In this work the microbial community of different organs (head, abdomen, and genitalia) of 41 P. spumarius was assessed by culturing methods. Overall, 86 isolates classified in 51 operational taxonomic units (OTUs) (41 bacteria and 10 fungi) were obtained, being found 2 OTUs on average per insect. The most abundant genera were Curtobacterium (within bacteria) and Cladosporium (within fungi). The abdomen has the highest number of microbial isolates and fungal diversity with about 0.32 OTUs per sample, while genitalia harbored the highest bacterial diversity with about 0.68 OTUs per sample. The bacterial isolates able to growth in artificial medium were selected, and their influence on the insect cycle and reproduction were assessed using an insect model. The observed effects on insects were variable depending on the bacterial isolates. Some bacteria demonstrated ability to increase insect population while other bacterial isolates displayed a negative effect by decreasing insect reproduction or by causing insect premature death. Although preliminary, these results are very promising for the management of P. spumarius population and, consequently, for the transmission of X. fastidiosa.