Both isolates were positive to the Congo Red test and able to SB431542 grow on xylan in pure culture [2] but their hydrolytic activity on plant polymers in situ has to be demonstrated (as, for example, it might be inhibited by sap sugars). The gut of insects that rely on sugar-based diets, particularly those belonging to the orders Diptera, Hymenoptera and Hemiptera, are often

dominated by acetic acid bacteria (AAB), [16]. Although the larval RPW diet is almost exclusively based on sugars, we were unable to detect AAB using a consolidated method based on the Akt inhibitor enrichment culture technique [42]. Moreover, the absence of AAB in the RPW gut was confirmed by deep sequencing, where only two sequences were affiliated to the genus Acidisoma (Acetobacteriaceae) (Additional file 2). AAB are Selleck C646 common in sugary acidic and alcoholic habitats, but are usually limited by nutrients other that their primary carbon source. AAB are common in fruit-feeding Drosophila species but are absent in flower-feeding flies [21]. Their absence in the RPW larvae could be explained by microbial interactions occurring inside the gut. The enrichment cultures set to specifically isolate AAB led, instead, to the isolation of Klebsiella strains that could outcompete AABs and that could fulfil also the nitrogen fixation function [20, 43], allowing the insect to live on a substrate with a high C/N ratio. Conclusions The RPW microbiota is composed mainly of facultative

and obligate anaerobic bacteria with a fermentative metabolism. These bacteria might have a key role in the insect nutrition, and other functions that need to be investigated. Further research, focusing on the functional traits of the bacteria inhabiting the gut of R. ferrugineus, is critically important to establish if some bacteria may exert an essential role for the insect or might represent an obstacle for the optimization and promotion of the use of entomopathogenic fungi and bacilli in an integrated pest management approach. Methods Sampling of RPW larvae 4-Aminobutyrate aminotransferase and gut extraction Field caught RPW late instar

larvae (hereafter called larvae) were collected in Winter and Spring from infested palms of the species Phoenix canariensis Chabaud, located in the urban and peri-urban area of Palermo, and in San Vito Lo Capo (Trapani), (Italy) (Additional file 1). The palms were cut down following phytosanitary measures for the control and eradication of R. ferrugineus (Regional Decree 6 March 2007). The palms were not treated by chemical or biological pesticides. The temperature was measured in 6 healthy and 6 infested palm trees during sampling at April 2011. Temperature was measured using a Bi-metal control digital thermometer (Wika – 360A005A4HS) by burrowing a small hole in the trunks, where the probe was inserted inside the palm trees. The average temperature of infested palm trees was 32.13°C ± 0.83, while the average temperature calculated at the same time for healthy palm trees was 25.95°C ± 0.