Understanding the ability of Pachycrepoideus vindemiae (Hymenoptera: Pteromalidae) to find and parasitize buried Diptera pupae in southwestern Colombia

Abstract

Pachycrepoideus vindemiae is a generalist wasp parasitoid released for biological control of the pupal stage for several species of Tephritoidea and Muscoidea flies that limit production of fruits and poultry commodities, respectively, worldwide. The parasitoid wasp must find buried host pupae to oviposit on them, and several factors may influence this outcome. The objectives of this study were to determine the capacity of first, host larvae to burrow to pupate according to substrate humidity and second, the parasitoid wasp to burrow and parasitize buried host pupae according to different conditions (substrate type, host species and parasitization time exposure). Moreover, comparison of chemical profiles between host’s pupae potentially involved for host location by the parasitoid was realized by GC-FID. Peat humidity significantly affected the burrowing depth of Dasiops inedulis and Anastrepha striata and both species buried significantly deeper in peat with 50% humidity than in dry conditions. The number of emerged parasitoids is not different between the two tested host species. P. vindemiae performance was better in peat than in crop soil. In peat wasps’ parasitism is similar between buried pupae located at 0 mm or 10 mm depth regardless of the time of exposure to the parasitoid. Cuticular chemical profiles showed that the four-host pupa species studied did not share compounds. However, A. striata shared some compounds with D. inedulis and, M. domestica shared some with C. capitata. Common compounds were found in the extracts of parasitized and non-parasitized pupae of C. capitata, D. inedulis and M. domestica.