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

Abstract

Ceratitis capitata (Wiedemann) is a cosmopolitan pest of economic importance. It is controlled by using the Sterile Insect Technique (SIT), which involves rearingand release of sterile males destined to mate with wild females, causing generation-togeneration suppression. Medflies are colonized by microorganisms, primarily the Enterobacteriaceae, with the genera Klebsiella and Enterobacter being the most common. Suchmicrobiota 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 Medflymicrobiota on resistance to abiotic stress conditions, evaluating its function under: (i) starvation, (ii) elevated temperatures, and (iii) dry environments. These conditions simulatechallenges 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 withwater containing a mixture of antibiotics and methylparaben. Treatment with antimicrobials effectively reduced the gut microbiota. While starvation had no significant effect onsurvival, a higher proportion of aposymbiotic individuals died earlier at 30 °C and underdry humidity, with the effect being more pronounced after 48 h. Our results suggest thatmicrobiota plays a role in adaptation of Medfly under environmental stress. We report forthe presence of a culturable yeast in the digestive tract of C. capitata, Zygosaccharomycesrouxii. Providing a probiotic adult diet with bacteria and Z. rouxii prior to release couldimprove SIT outcomes under adverse conditions.