Effect of gut microbiota on host use by Anastrepha spp.

The gut microbiota is key for the homeostasis of some phytophagous insects, but there are still few studies documenting its role on host use by stenophagous or polyphagous fruit flies. Guava (Psidium guajava) is a fruit infested in nature by the tephritids Anastrepha striata and A. fraterculus. In contrast, A. ludens only infests guava under artificial conditions, but unlike A. striata and the Mexican A. fraterculus, it infests oranges (Citrus aurantium) and several other Rutaceae. We used these models to analyze whether gut microbiota could explain the differences in host use observed in these fly species and to test the gut microbial host use facilitation hypothesis (Hammer & Bowers 2015). We compared the gut microbiota of the larvae of the three species when they developed in guava and the microbiota of the fruit pulp larvae fed on. We also compared the gut microbiota of A. ludens developed in C. aurantium with the pulp microbiota. In A. ludens, the composition of the gut microbiota is strongly influenced by environmental microbiota. In contrast, the gut microbiota of A. striata and A. fraterculus were dominated by Wolbachia and was significantly different from the microbiota of the guava pulp. Functional predictions suggest that the gut microbiota of A. striata and A. fraterculus are enriched in detoxification functions. The dominance of Wolbachia in the gut microbiota of A. striata and A. fraterculus represents the first report on the possible role of Wolbachia in facilitating host use in phytophagous insects.