COEVOLUTION BETWEEN FERGUSOBIA AND FERGUSONINA MUTUALISTS

Authors: GIBLIN-DAVIS, R. - UNIV.FL.,FT.LAUDERDALE; Scheffer, Sonja; DAVIES, K. - UNIV.ADELAIDE,AUSTRALIA; TAYLOR, G. - UNIV.ADELAIDE,AUSTRALIA; CUROLE, J. - UNIV.NEW HAMP., DURHAM,NH; CENTER, T. - USDA,ARS, DAVIE,FL; GOOLSBY, J. - USDA,ABC LAB, QUEENSLAND,; THOMAS, W. - UNIV.NEW HAMP., DURHAM,NH

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2003
Publication Date: 8/9/2003
Citation: Giblin-Davis, R.M., Scheffer, S.J., Davies, K.A., Taylor, G.S., Curole, J., Center, T.D., Goolsby, J., Thomas, W.K. 2003. Coevolution between fergusobia and fergusonina mutualists. Nematology Monographs and Prospectives 2: 1-11

Interpretive Summary: The paperbark tree, Melaleuca quinquenervia, is a highly invasive species in the Florida Everglades and is currently a focus of major control efforts by several agencies. The use of biological control agents against the paperbark tree is a promising method for controlling the further spread of this plant. One candidate agent for use in Florida is the Fergusonina fly that in association with a nematode worm produces galls on paperbark flower shoots. This research investigated the evolutionary relationships between the flies and the nematode species that are associated with them. The results of this research provide information regarding the evolutionary history of the fly and nematode species. This information will be of interest to entomologists, nematologists, and evolutionary biologists as it provides new information that may be of use in weed control.

Technical Abstract: The associations between Fergusobia nematodes (Neotylenchidae) and Fergusonina flies (Fergusoninidae) represent the only putative example of nematode and arthropod-associated mutualism. The nematode appears to induce a bud or leaf gall that both organisms use while the fly provides gall maintenance, dispersion, and sustenance for the nematode. Based upon molecular analysis, this is a potentially large monophyletic radiation of more than 50 mostly undescribed species of nematodes and flies that exhibit a high degree of host specificity within the Australasian Myrtaceae (mostly Leptospermoideae; e.g., Eucalyptus, Corymbia, Angophora, and Melaleuca). The Agromyzidae (with no known nematode associates) is the putative sister group to the Fergusoninidae. Fergusobia could have evolved from parasitic nematodes similar to present day Howardula that parasitized the cyclorrhaphan stem ancestor of Fergusonina flies and developed a plant-parasitic association that provided a mutual benefit to fly host and nematode. Alternatively, Fergusobia could be related to present day anguinids that produced aboveground galls and developed an association with an agromyzid ancestor. In either case, the evolution of the host-parasite interaction requires that host fly resistance and nematode virulence be moderated in female flies because they are always associated with nematodes.