Response of Anastrepha fraterculus Wiedemann (Diptera: Tephritidae) to synthetic semiochemicals

CARRIZO, B.; RUIZ, M. J.; GOANE, L.; BACHMANN, G.; MILLA, F.; SEGURA, D.F.; KUZMICH, D.; WALSE, S.; VERA, M.T.

Sydney

Simposio; 11th International Symposium on Fruit Flies of Economic Importance; 2022

Background: Specific attractants are a powerful tool for pest management. The efficient synthesis of epianastrephin and anastrephin, present in the male sex and aggregation pheromones of several Anastrepha species, and a synthetic analog of epianastrephin with two methyl groups (dimethyl), opened a new possibility to develop a specific attractant within this genus. Methods: The response of A. fraterculus males and females, of different age and matingstatus, to synthetic semiochemicals was evaluated through electroantennographic analysis (EAG) and field cage experiments. Sexually-immature flies, sexually-mature virgin females and sexually-mature mated flies were tested. For EAG analyses, epianastrephin was included as a control to compare the antennae depolarization following dimethyl exposure. For field cages experiments, epianastrephin was provided jointly with anastrephin in two proportions and dimethyl was evaluated alone. In each cage, two traps hung from the roof of the cage, one with one attractant and one without attractant. One hundred flies of a given sex, age and mating status were released inside the cage and left for 16 h. Number of flies captured in each trap was recorded. Control cages contained a trap with five confined live mature males (leks). For immature flies, an additional positive control cage was set up with torula yeast. A liner model was built to analyze EAG response with sex, semiochemical and physiological condition as fixed factors. Field-cage data were compared using a Wilcoxon test for paired samples. Results: Epianastrephin and dimethyl were EAG+ for all the flies’ conditions; with epianastrephin eliciting the highest response for both sexes of all fly physiological conditions and immature flies showing greater responsiveness than mature ones. Attractiveness in the field cage experiments was dependent of the sex and the physiological condition. Immature flies showed attractiveness only to leks; virgin females to leks, dimethyl and both epianastrephin formulations; mature-mated males to leks, dimethyl and one epianastrephin formulation; and mature-mated females only to leks.Conclusion: Our bioassays showed that traps baited with synthetic semiochemicals are attractive to A. fraterculus males and females being this attraction dependent on the status of the fly. Dimethyl showed a promising performance since it elicited the same response than epianastrephin. The attraction observed to the leks in all mating status and ages evaluated suggests that the blend released by the calling males may contain food and host cues which could be acting as a sensory trap. The addition of any of these compounds in the synthetic attractants may results in a greater attraction and deserves further evaluation. Dose response experiments will provide additional information to move a step forward and validate the results obtained in open field conditions.