Bacteria associated to Anastrepha fraterculus (Diptera: Tephritidae): characterization and effect on sterile males sexual competitiveness.

DF SEGURA; LANZAVECCHIA, S.B; M. TERESA VERA; FERNÁNDEZ, PC; C CONTE; MANNINO, CONSTANZA; CLADERA, J

Encuentro; FIRST RESEARCH CO-ORDINATION MEETING On ?Use of Symbiotic Bacteria to Reduce Mass-rearing Costs and Increase Mating Success in Selected Fruit Pets in Support of SIT Application?; 2012

Research scientists in Argentina are devoting efforts to develop the sterile insect technique against the South American fruit fly, Anastrepha fraterculus, a key fruit pest in America. The experience gained in other tephritid fruit fly species and transferred to A. fraterculus will surely result in a better performance of the sterile male in the field, particularly in topics such as sexual competitiveness. Increased mating performance of sterile males would allow a higher overall efficacy of the SIT. In addition, sexual competitiveness has been tightly linked to nutritional status in fruit flies, which in turn has been shown to be affected by symbiotic associations with gut bacteria. Preliminary results from our laboratory indicate that in A. fraterculus this may also be the case. The main objective of the present project is to describe the gut bacteria associated to A. fraterculus and explore the importance of this association on the reproductive success of the males. We will also focus on the effect of colonization and irradiation of adult insects on bacteria diversity. Males? reproductive success will be assessed by standard mating competitiveness tests, where female choice between males treated with antibiotics and un-treated males will be registered. Changes in the sex pheromone and cuticle hydrocarbons due to the presence of specific bacteria will also be tested. The species richness of the bacteria in the gut will be determined by means of PCR amplification of 16S rRNA gene and sequencing. Effect of irradiation on bacterial diversity and mating competitiveness will be further included in this project. In addition, bacterial symbionts have also been found to influence the ability of certain dipterans to cope with the attack of parasitoids, through an enhancement of the immune response of the host. Tephritid fruit flies are known to carry the symbiotic bacteria Wolbachia, mainly located in the gonads, which in other insects strengthen their immune system. If this is also the case in tephritid fruit flies, then the presence of Wolbachia will increase the production cost of parasitoids, as some of the parasitized, Wolbachia-carrying, larva would be able to stop parasitoid development. The present project will contribute to better understand the relationship between bacterial symbionts and A. fraterculus in two aspects that will surely contribute to the management of this pest in South America.