Acceptability and suitability of six fruit fly species (Diptera: Tephritidae) for Kenyan strains of Psyttaliaconcolor (Hymenoptera: Braconidae)

Abstract

Host acceptability and suitability Psyttalia concolor (Szépligeti) is a koinobiont, larval parasitoid of tephritid fruit flies. Individuals of P. concolor were field-collected from coffee in the central highlands of Kenya, and cultured initially on Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann). They were then examined for their ability to oviposit in and develop on five other tephritid species that are pests in Kenya. In addition to the medfly, acceptability for oviposition and suitability for development were tested against the mango fruit fly, Ceratitis cosyra (Walker), the Natal fruit fly, Ceratitis rosa Karsch, Ceratitis fasciventris (Bezzi), Ceratitis anonae Graham and the melon fruit fly, Bactrocera cucurbitae (Coquillett). Ceratitis capitata and C. cosyra were accepted as hosts significantly more often than the other species. Superparasitism was recorded only from C. capitata and C. cosyra. Two days after oviposition, parasitoid eggs in C. fasciventris and B. cucurbitae were encapsulated, whereas those in C. rosa and C. anonae were encapsulated, and often melanized. Ceratitis capitata was the most suitable host for Kenyan populations of Psyttalia concolor in terms of progeny production, and proportion of female progeny.

Keywords:

• Fruit flies
• Psyttalia concolor
• acceptability
• suitability
• host range

Acknowledgments

We thank Dr N. Zenz and the fruit fly rearing technicians for providing the host larvae. The assistance of Mr Gerphas O. Ogolla in larval dissection and Marcia Trostle in identification of host puparia is also acknowledged. We are grateful to Dr Tim Holler and Dr Eric Jang for reviewing the earlier version of the manuscript. This work has been supported from several sources, including USDA-CSREES Special Grant No. 96-34135, Tropical and Subtropical Agricultural Research (to R. Messing, University of Hawaii), Caribbean Basin Administrative Group grant no. 96-34135-3016 (to R. Baranowski, University of Florida and J. Sivinski, USDA/ARS), USDA-CSREES/IFAFS Grant No. 00-52103-9651 (to Texas A&M University), the IFAD (B2103B-018) funded African Fruit Fly Initiative and the German Academic Exchange Services (DAAD).