Gut bacterial communities in the Mediterranean fruit fly (Ceratitis capitata) and their impact on host longevity

Fruit flies (Diptera: Tephritidae) harbor stable bacterial communities in their digestive system, composed mainly of members of the Enterobacteriaceae. However, the Enterobacteriaceae are not the sole community in this habitat. We examined the hypothesis that Pseudomonas spp. form a cryptic community in the gut of Ceratitis capitata, the Mediterranean fruit fly (‘medfly’). Suicide polymerase restriction PCR (SuPER PCR), a novel culture-independent technique, revealed that Pseudomonas spp. form minor, common and stable communities within the medflyʹs gut. These include P. aeruginosa, a known pathogen of arthropods. Experimental inoculations with high levels of P. aeruginosa reduced the medflyʹs longevity while inoculations with members of the Enterobacteriaceae extended the flyʹs life. ingly, we suggest that in addition to their possible contribution to the flyʹs nitrogen and carbon metabolism, development and copulatory success (as shown in previous studies), the Enterobacteriaceae community within the medflyʹs gut may also have an indirect contribution to host fitness by preventing the establishment or proliferation of pathogenic bacteria.