DNA Probes Can Be Used To Discriminate between Tephritid Species at all Stages of the Life Cycle (Diptera: Tephritidae)

Abstract

We isolated DNA sequences from the genomes of three Tephritid species. These can be used as probes to make rapid and reliable species identifications using material from any stage of the life cycle. The three Tephritid species are the Mediterranean fruit fly, Ceratitis capitata (Weidemann); the oriental fruit fly, Bactrocera dorsalis (Hendel), and the melon fly, Bactrocera cucurbitae (Coquillett). These isolated DNA sequences can be used to probe specimen material such as single eggs, larvae, or adult body parts on dot blots or squash blots to determine rapidly which species are present when infestations are found. The actual species identifications are made either on the basis of a direct positive result with a particular probe or by the process of elimination from multiple probings. The availability of species-specific DNA probes for use on minimal amounts of material from any stage of the life cycle or body part can facilitate greatly the identification of specimens which are otherwise indistinguishable or unsuitable for classification on the basis of morphological criteria. This technique also allows material to be analyzed immediately, which obviates the need for rearing and handling of material collected at immature stages. Although these probes have been developed for the three Tephritid species described here, the methods used are applicable to any group of organisms.