Response of the Fruit Fly ParasitoidDiachasmimorpha longicaudata(Hymenoptera: Braconidae) to Mango Fruit Volatiles

Abstract

The response of Diachasmimorpha longicaudata (Ashmead) females to mango fruit that were intact (healthy), mechanically damaged, or infested with Anastrepha ludens (Loew) larvae, and their respective hexanic and methanolic extracts, was studied using behavioral, electrophysiological, and chemical techniques. Female parasitoids significantly preferred to visit infested mangoes and their extracts over healthy and mechanically damaged mangoes in wind tunnel and field cage bioassays. This suggests that the presence of the larvae inside the fruit is of clear importance in the host location behavior performed by this species. Methanolic extracts of infested mangoes evoked a significant electroantennography (EAG) response in female antennae compared with the responses elicited by solvent, healthy, and mechanically damaged mango extracts, but EAG response to hexanic extracts of infested mangoes was only significant compared with solvent control. Most of the compounds found in infested mango hexanic extracts were commonly found in healthy and mechanically damaged mango hexanic extracts, except 2-phenylethyl acetate, which seems to be exclusively present in infested mangoes. Also, infested mango extracts contain several compounds in higher amounts compared with the other two types of mangoes, as do the methanolic extracts from infested mangos. These differences could explain why female parasitoids preferred to visit infested mangos, with their correspondent methanolic and hexanic extracts. Our results suggest that this species uses a complex mixture of compounds for host location.