Behavioural and electrophysiological response of Anastrepha fraterculus (Diptera: Tephritidae) to a gamma-lactone synthetic semiochemical

Authors: GOANE, LUCIA - National University Of Tucuman; CARRIZO, BEATRIZ NOEMI - National Institute Of Agricultural Technology(INTA); RUIZ, MARIA JOSEFINA - National Institute Of Agricultural Technology(INTA); BACHMANN, GUILLERMO - National Institute Of Agricultural Technology(INTA); MILLA, FABIAN - National Institute Of Agricultural Technology(INTA); SEGURA, DIEGO FERNANDO - National Institute Of Agricultural Technology(INTA); KUZMICH, DANIEL - Former ARS Employee; Walse, Spencer; VERA, MARIA TERESA - National University Of Tucuman

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2023
Publication Date: 2/18/2023
Citation: Goane, L., Carrizo, B., Ruiz, M., Bachmann, G.E., Milla, F., Segura, D., Kuzmich, D., Walse, S.S., Vera, M. 2023. Behavioural and electrophysiological response of Anastrepha fraterculus (Diptera: Tephritidae) to a gamma-lactone synthetic semiochemical. Insects. 14(2). Article 206. https://doi.org/10.3390/insects14020206.
DOI: https://doi.org/10.3390/insects14020206

Interpretive Summary: Tephritid fruit flies must be controlled in horticultural production areas, as their presence decreases marketability. In tropical and subtropical regions of the Americas, species from the genus Anastrepha are a threat and the development of effective trapping systems is a key element of Integrated Pest Management programs. Certain Anastrepha sp., such as A. fraterculus, naturally produce volatile '-lactones as aggregation pheromones. Here we evaluate the electrophysiological and behavioral response of A. fraterculus to one such pheromone, epianastrephin, and compare it to a structural analog, which is simpler to manufacture for potential use in regional trapping programs. The structural analog elicited an equivalent response compared to epianastrephin in the bioassays, a promising result that merits a myriad of future studies. In broader context, this work represents an international collaboration that hastens scientific progress toward controlling this geographically widespread genus of insect pests.

Technical Abstract: Attractants are a powerful tool for pest management. The lack of specific attractants for Anastrepha fraterculus, a complex of cryptic species of great economic importance in South America, makes it difficult to monitor the pest in the field. The '-lactone male sex and aggregation pheromones of several Anastrepha species, naturally released in a 7:3 epianastrephin to anastrephin ratio, and a synthetic 'gamma-lactone analog with gem-dimethyl groups (dimethyl) at C(4), were evaluated as potential attractants within this genus. Different age and mating status of A. fraterculus males and females were evaluated during electroantennography (EAG) and field cage experiments in which polymeric lures were deployed to contain 100 mg of attractant. Epianastrephin and dimethyl were EAG+ for all fly conditions; with epianastrephin eliciting the highest response for both sexes; and immature flies showing greater responsiveness than mature ones. In field cages, immature flies showed attractiveness only to leks; virgin females to leks, dimethyl and both epianastrephin-anastrephin formulations (95 and 70 wt.% epianastrephin); mature-mated males to leks, dimethyl and 70 wt.% epianastrephin; and mature-mated females only to leks. Our bioassays showed a promising performance of the analog dimethyl since it elicited the same response as epianastrephin, requires less steps to synthesize and contains one less chiral center than the natural pheromones. The attraction to leks was recorded for all mating status and ages of flies and suggests that calling males may have released food and host cues which could be acting as a sensory trap. The addition of any of these compounds in the synthetic attractants may result in a greater attraction and thus deserves further evaluation. Dose response experiments will provide additional information to move a step forward and validate the results obtained in open field conditions.