Sexual Success of Anastrepha fraterculus Males is Affected by Gut Bacteria and Diet

JUÁREZ, M.L.; PIMPER, L.E. ; CONTE, C.A. ; SEGURA, D.F. ; LANZAVECCHIA, S.B. ; CLADERA, J.L.; GOANE, L. ; RUIZ, M.J. ; VERA, M.T.

Congreso; The 9th International Symposium on Fruit Flies of Economic Importance; 2014

Background: Fruit flies have symbiotic bacteria in their digestive tract and this can result in an increase of their reproductive success. Additionally, male mating success is conditioned by the nutritional quality of the diet. Yet, it is still not clear to what extent the bacteria can contribute towards counteracting nutritional deficiencies. Our objective was to evaluate the effect of adding antibiotics in different adult diets on the mating success in wild and laboratory-reared A. fraterculus males. Methods: Wild (W) and laboratory-reared (L) males were provided one of two different diets sugar (S) or sugar + protein (S+P), which in turn could have or not antibiotics (AB). This resulted in four treatments: 1) S; 2) S+AB; 3) S+P; 4) S+P+AB. To evaluate the mating competitiveness of the males from different treatments, one virgin wild female was released in a laboratory cage containing two males from the same origin as well as diet, but with different antibiotic treatments (i.e., W-S vs W-S+A or L-S+P vs L-S+P+AB). The number of copulations obtained by each type of male, copula duration and the time elapsed since the release of the females and the initiation of copula (latency) were recorded. Subsequently, the individuals were stored at -20°C to characterize the symbiotic flora by DGGE of 16S rRNA gene fragments. Results: The addition of antibiotics resulted in a significantly lower number of matings while the diet and the origin of the males had no effect on this variable. The interaction between antibiotic treatment and male origin was close to significance (p = 0.065) and when the origins were included in the post-hoc comparisons, the effect of the antibiotic was significant only for laboratory males. The diet in itself had an impact on male mating; males fed with S copulated less in relation to males fed with S+P, irrespective of having received antibiotics or not. Latency to mate depended on male origin; laboratory-reared males mated earlier than wild males with no effect of antibiotic treatment while for wild males the antibiotic treatment increased latency. Mating duration was affected by the diet for wild males but not for laboratory males; wild males fed with S have shorter copula than males fed with S+P. Samples collected from the flies treated with antibiotics have similar DGGE patterns, with dominant bacteria from the Alphaproteobacteria group and the genus Stenotrophomonas (Gamaproteobacteria), and no bacteria from the family Enterobacteriaceae. In addition, wild males fed with S+P showed the greatest diversity in the gut community. Conclusions: The three factors evaluated affected male sexual success in A. fraterculus. The addition of antibiotic to the adult diet decreased the number of copulations; the origin and the antibiotic treatment had an effect on latency and the diet and origin on copula duration. These results support the hypothesis of a symbiotic relationship between gut bacteria and their hosts, but yet more evaluations are needed to confirm such interaction.