Submitted to: Annals of the Entomological Society of America
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/10/2004
Publication Date: 9/1/2004
Citation: Eitam, A., Sivinski, J.M., Holler, T., Aluja, M. 2004. Biogeography of braconid parasitoids of the caribbean fruit fly (Diptera: Tephritidae) in florida. Annals of the Entomological Society of America. 97(5):928-939. Interpretive Summary: Tephritid fruit flies attack scores of fruits and vegetables, and because of quarantines, restrict the development of agricultural exports around the world. Fruit flies have many natural enemies which contribute to the control of pest populations. One means of understanding the conditions that allow a particular parasitoid to flourish is to examine its geographic distribution and then determine what factors limit its spread. These limiting factors can be both abiotic (cold, heat, and moisture) or biotic (other species of parasitoid, the availability of certain host plants, etc.). USDA-ARS scientists found that in the braconid parasitoids attacking the Caribbean fruit fly in Florida, abiotic and biotic factors interact so that one species, Diachasmimorpha longicaudata, is able to outcompete another species, Dorytobracon areolatus, in the southern part of the state, while the situation is reversed in the northern portion. Understanding such hinteractions will guide future efforts to biologically control the Caribbean fruit fly and other pest fruit flies by identifying optimal environments for the introduction, or mass-rearing and augmentative release, of these important parasitoid species.
Technical Abstract: The geographic distributions of braconid parasitoids of the Caribbean fruit fly, Anastrepha suspensa (Loew), were determined by collecting host fruit throughout central and southern Florida. Diachasmimorpha longicaudata (Ashmead) was mostly limited to southern Florida, reaching higher latitudes along the Atlantic and Gulf coasts. Distribution of this species was related to several temperature variables, but most significantly, negatively related to variance of monthly temperatures. This suggests that D. longicaudata may be dependent on a relatively constant supply of hosts. Doryctobracon areolatus (Szepligeti) was the dominant species at the majority of interior locations, but uncommon or absent along both coasts. Utetes anastrephae (Viereck) was widespread, but usually less common than the other species. Parasitism levels of both D. areolatus and D. longicaudata were positively related to density of common guava, Psidium guajava L., trees. Parasitism levels of both D. longicaudata and U. anastrephae were positively related to numbers of A. suspensa captured in McPhail traps. Abundance of D. areolatus was inversely related to that of both D. longicaudata and U. anastrephae. The absence of D. areolatus in southeast Florida, where it was originally established, suggests that a process of competitive displacement may have occurred. Parasitoid distribution is consistent with the hypothesis that D. areolatus is a superior searcher and D. longicaudata is a superior intrinsic competitor.