Ceratitis capitata microbiota and its effect on environmental stress tolerance: making flies stronger

Ceratitis capitata (Wiedemann) is a cosmopolitan pest of economic importance. It is controlled by using the Sterile Insect Technique (SIT), which involves rearing and release of sterile males destined to mate with wild females, causing generation-to-generation suppression. Medflies are colonized by microorganisms, primarily the Enterobacteriaceae, with the genera Klebsiella and Enterobacter being the most common. Such microbiota contributes to host fitness. During the SIT, diet with antibiotics and irradiation for sterility of adults alter microbiota. We aimed to determine the role of Medfly microbiota on resistance to abiotic stress conditions, evaluating its function under: (i) starvation, (ii) elevated temperatures, and (iii) dry environments. These conditions simulate challenges Medfly may encounter after release, which differ from controlled rearing environments. We compared adult survival between symbiotic and aposymbiotic individuals, under starvation, two thermal regimes (25 and 30 °C) or two humidity regimes (20%-25% and 80%-90% R.H.). Aposymbiotic individuals were obtained after providing them with water containing a mixture of antibiotics and methylparaben. Treatment with antimicrobials effectively reduced the gut microbiota. While starvation had no significant effect on survival, a higher proportion of aposymbiotic individuals died earlier at 30 °C and under dry humidity, with the effect being more pronounced after 48 h. Our results suggest that microbiota plays a role in adaptation of Medfly under environmental stress. We report for the presence of a culturable yeast in the digestive tract of C. capitata, Zygosaccharomyces rouxii. Providing a probiotic adult diet with bacteria and Z. rouxii prior to release could improve SIT outcomes under adverse conditions.