Identification of volatile compounds obtained from larvae-infested and rotten fruit attractive to the fruit fly parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae).

DEVESCOVI, FRANCISCO; FERNANDEZ; BACHMANN, GUILLERMO E.; NUSSENBAUM, ANA LAURA; SCHIAVO; DIEGO F. SEGURA

Congreso; 9th Meeting of Tephritid Workers of the Western Hemisphere; 2016

Females of the fruit fly parasitoid, Diachasmimorpha longicaudata, are able to locate their host habitat using chemical information. Previous studies have shown that volatiles released by fruit infested by Ceratitis capitata Wiedemann (Diptera: Tephritidae) larvae, as well as rotten (but non-infested) oranges (Citrus sinensis Osbeck var. navel) attract females in laboratory arenas with no air flux. The aim of this study was to confirm the chemical basis of the orientation behavior of D. longicaudata towards its host using a dynamic olfactometer, and determine the candidate compounds associated to that behavior. We evaluated whether parasitoid females are using cues from infested and non-infested, rotten fruit within a Y-tube olfactometer and confirmed those results, suggesting that air borne compounds are responsible for the attractiveness. We then collected the volatile compounds from infested, rotten and intact oranges by dynamic head-space sampling using HayeSep Q traps. After elution with methylene chloride, volatiles were analyzed by GC-MS and were identified using the NIST library. Significant quali- and quantitative differences were found between the GC profiles of infested and rotten fruit when compared with non-infested fruit. Some compounds [such as α- pinene; β-pinene, and D-limonene] were found in larger amount both in infested and rotten oranges compared with control oranges and therefore may be associated to fruit decomposition. On the other hand, several compounds were found only in infested fruit, including ethyl-2-hexanoate; (-)-Terpinen-4-ol; 2,6-Octadiene, 2,6-dimethyl-; methyleugenol among the most abundant. Likewise, specific compounds were found only in rotten fruit, like (+)-4-Carene; Acetic acid, octyl ester and trans-p-Menthan-3-one. These results constitute a promising base to continue studying the role of specific compounds on the orientation behavior of D. longicaudata females.