Long term oviposition deterrent activity of Anastrepha fraterculus feces

BACHMANN GUILLERMO; FERNÁNDEZ; M.T. VERA; DF SEGURA

Congreso; X Meeting of the Fruit Fly Workers of the Western Hemisphere.; 2020

Background: After oviposition, females from several tephritid species, including A. fraterculus, deposit host marking pheromones (HMPs) that reduce the probability of further egg laying events, and consequently larval competition. HMPs were isolated in other Anastrepha spp. through dissolution of their feces in water. The rejection of fruit as oviposition substrate caused by HMPs has generated interest as a potential tool to reduce infestation levels, as part of an integrated pest management program. In order to promote the development of non-contaminant control tools, we evaluated the deterrent effect of A. fraterculus feces on the behavior of conspecific females.Methods: The feces of A. fraterculus were dissolved in water and the solution was used in the following two experiments. 1- Behavioral recordings: two cylindrical slices of pear (2 cm in diameter, 0.5 cm in height and with their rinds intact) were placed in a Petri dish, separated 5 cm from each other. One of the slices was treated with the solution and other was non-treated. The Petri dish was introduced in a glass container that housed one mated female. The slice visited and the occurrence of oviposition were recorded. 2- Oviposition patterns: groups of 6 mated females were offered artificial oviposition substrates (10 ml vials filled with colored water and wrapped in Parafilm) treated or non-treated with the solution. After 30 min, the vials were removed and the number of vials that were accepted for oviposition as well as and the number of eggs laid, were recorded. The HMP extracts were applied treatment with the solution was made at 0, 7 and 14 days before the experiments, except for experiment 1 for which 14 days treatment was not feasible .Results: Behavioral recording showed that treated slices of pear were less frequently visited than non-treated slices. Once on the slice, females rejected to lay eggs more frequently on treated slices. In the oviposition patterns experiment, females laid less eggs in treated substrates, and these substrates were chosen less frequently for oviposition. Time since treatment with HMP extracts did not affect the rejection frequency.Conclusion: The results suggest that the feces of A. fraterculus contain compounds that trigger oviposition deterrence at least for 14 days after treatment. More behavioural and chemical studies are needed to fully necessary for understand whether deterrence is caused by specific compound of the females? feces or females are responding to if the oviposition deterrence is mediated by pheromonal or bacterial-derived compounds.