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ARS Home » Southeast Area » Fort Lauderdale, Florida » Invasive Plant Research Laboratory » Research » Publications at this Location » Publication #139656
Title: COEVOLUTION BETWEEN FERGUSOBIA AND FERGUSONINA MUTUALISTS

Author
item GIBLIN-DAVIS, R - UNIVERSITY OF FLORIDA
item SCHEFFER, S - USDA, ARS
item DAVIES, K - U OF ADELAIDE, AUSTRALIA
item TAYLOR, G - U OF ADELAIDE, AUSTRALIA
item CUROLE, J - U OF NH
item Center, Ted
item GOOLSBY, J - USDA, ARS
item THOMAS, W - U OF 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., Curole, J., Center, T.D., Goolsby, J., Thomas, W.K. 2003. COEVOLUTION BETWEEN FERGUSOBIA AND FERGUSONINA MUTUALISTS. Journal of Nematology. 2:1-11. 2003.

Interpretive Summary: Mutualisms in biology involve two or more organisms living together for their mutual benefit. There are many cases of mutualism known, but none reported involving nematode worms and insects. The melaleuca gall fly and its associated nematode represents and insect/nematode mutualism in which the nematode causes the host plant to produce nutritive (gall) tissue that is fed upon by both species, while the fly maintains the gall, nurtures the nematodes, and moves them from plant to plant. Genetic analysis of the flies and nematodes that feed on several related species of Australian plants suggests that they are all distinct but closely related species. They have apparently speciated together so that each species of plant has its own unique fly with its own unique nematode. This suggests that they are highly specialized and safe to use to control melaleuca in south Florida where it has invaded Everglades habitats.

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 above-ground 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.