Direct and indirect host-related volatile compounds attract a fruit fly parasitoid, Diachasmimorpha longicaudata

DEVESCOVI FRANCISCO; FERNANDEZ PATRICIA CARINA; BACHMANN GUILLERMO; NUSSEMBAUM ANA LAURA; DIEGO FERNANDO SEGURA

Entomologia Experimentalis et Applicata

John Wiley and Sons Inc

Año: 2024

Fruit fly pests (Diptera: Tephritidae) are a serious problem for fruit production andfor local and international trade. Biological control is increasingly included as apest control tool within integrated pest management (IPM) programmes, seekingto reduce pesticides and improve fruit quality. Ceratitis capitata Wiedemann, theMediterranean fruit fly (medfly), is probably the most damaging fruit fly pest, with aglobal distribution and more than 200 host species. The solitary larval endoparasitoidDiachasmimorpha longicaudata Ashmead (Hymenoptera: Braconidae) is a biocontrolagent widely used against Tephritidae fruit fly pests. Previous studies showed thatfemale wasps locate host larvae using visual, mechanical, and chemical cues. Here,we investigated the chemical basis of female parasitoid attraction to cues that guideD. longicaudata to the host, and thus unveil volatile organic compounds that mightbe used in IPM programmes. Female orientation to chemical cues was tested in aY-tube olfactometer, where attraction to C. capitata-infested oranges, oranges withresidues of larval activity, oranges infected with a green mould, and overripe orangeswas confirmed. Volatiles from all these types of fruit were collected and used in gaschromatography-electroantennographic detection (GC-EAD) and GC-mass spectrometry (MS) analyses. These studies allowed us to identify six candidate compoundsthat were present in all treated oranges but not in the control fruit (ripe and uninfested oranges): D-limonene, acetophenone, linalool, nonanal, decanal, and eugenol.Electroantennography (EAG) showed that acetophenone, nonanal, and decanal triggered dose-dependent responses, suggesting a relevant role in the process of hostfinding. Although responses to D-limonene, linalool, and eugenol were independentof the dose, they could be involved in host location in areas with high probability ofhost presence. The fact that these six compounds are shared by the four behaviourally attractive sources opens new possibilities for the development of novel tools toimprove biocontrol programmes.