To evaluate, using as model the major pest of commodities, Plodia interpunctella, and adopting a culture-independent approach, the impact of different food substrates on the host-associated bacterial communities.

The feeding behavior of insects may influence the associated bacterial community; this possibility and its magnitude are currently a matter of debate. Using as model the major pest of commodities, Plodia interpunctella, and adopting a culture-independent approach, the impact of different food substrates on the host-associated bacterial communities was evaluated. The analysis of similarity confirmed the differences among microbiotas of moths fed with five substrates and the diet is the only tested factor that explains the observed dissimilarity. The few bacteria shared between food and insect, provide evidences for a limited conveyance of bacteria to the host by diet; more likely, diets with different composition indirectly promote changes on the insect's microbiota. Moth microbiotas were characterized by two enterotypes, associated with insect fed on diet rich in carbohydrates and proteins, respectively. These results were also confirmed by statistical analyses performed on the predicted functional potential. A core microbiota composed of six taxa was shared between eggs and adults, regardless of the population of origin. The finding of possible human and animal pathogens on chili and in the microbiotas of moths fed on it, open to the possibility that P. interpunctella may convey, through frass, potential pathogens to stored products.