Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/1999
Publication Date: 2/1/2000
Interpretive Summary: Tephritid fruit flies infest scores of species of fruits and vegetables, and because of quarantines, hinder the development of agricultural-export economies around the world. Augmentative biological control is being developed as a means of pest fruit fly suppression, and one of the most promising parasitoid species for augmentation is the braconid, Diachasmimorpha longicaudata. There are many different agricultural environments containing tephritid pests, but not all of these may be suited to the environmental requirements of D. longicaudata. The correct use of this, or any other, natural enemy requires knowledge of its foraging behaviors. Scientists from the Agricultural Research Service's Center for Medical, Agricultural, and Veterinary Entomology in collaboration with colleagues from the Istituto de Ecologia (Xalapa, Veracruz, Mexico) performed wind tunnel and laboratory tests in order to determine fruit preferences and the reproductive capacity of D. longicaudata in Anastrepha spp. fruit flies from different host fruits. They found that a female's host fruit preferences were correlated to the growth and performance of her offspring. Work on host fruit preferences in this and other species will continue until it will be possible to tailor augmentative parasitoid releases to any particular time and place.
Technical Abstract: Naive female Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae), a solitary endoparasitoid of tephritid fruit flies, exhibited positive responses toward volatiles of host fruits in olfactometer and wind tunnel bioassays. Although no significant preference for one of the test fruits, mango (Mangifera indica L.) or grapefruit (Citrus paradisi Macfaden), was observed, number of flights in the wind tunnel was higher i presence of mangos. In the olfactometer trials parasitoids preferred fly infested over non infested grapefruits, and infested over non infested mangos. Reproductive performance bioassays were conducted using Anastrepha ludens (Loew) larvae (Diptera: Tephritidae) reared in grapefruit, orange, mango or artificial diet, and Anastrepha obliqua (Macquart) larvae reared in mango, as parasitoid hosts. Parasitoid performance was compared for two Anastrepha species and three fruit species. Significant effects of fruit fly species and of the diet of fruit fly larvae on longevity, size, and progeny production of D. longicaudata were observed. Anastrepha ludens reared in grapefruit was the best host in terms of offspring longevity, size, and number of female progeny, but parasitoids which developed in A. ludens reared in mango had higher overall fecundity. Anastrepha ludens reared in mango was a better host than A. obliqua in the same fruit. No correlation between parasitoid size and demographic parameters was found. The results of this laboratory study showed that host preference and offspring performance are partially related.