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Title: Fungal symbionts in three exotic ambrosia beetles, Xylosandrus amputatus, Xyleborinus andrewesi, and Dryoxylon onoharaense (Coleoptera: Curculionidae: Scolytinae: Xyleborini) in Florida

Author
item BATEMAN, CRAIG - University Of Florida
item Kendra, Paul
item RABAGLIA, ROBERT - Forest Service (FS)
item HULCR, JIRI - University Of Florida

Submitted to: Symbiosis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2015
Publication Date: 11/4/2015
Citation: Bateman, C., Kendra, P.E., Rabaglia, R., Hulcr, J. 2015. Fungal symbionts in three exotic ambrosia beetles, Xylosandrus amputatus, Xyleborinus andrewesi, and Dryoxylon onoharaense (Coleoptera: Curculionidae: Scolytinae: Xyleborini) in Florida. Symbiosis. Vol 66: pgs-141-148.

Interpretive Summary: Interpretive Summary Ambrosia beetles are small wood-boring insects that introduce symbiotic fungi into their host trees. Most species live in dead or dying trees and are not of economic importance. However, some exotic species can attack live trees and spread plant disease, as is the case with the redbay ambrosia beetle that vectors laurel wilt, a disease killing avocado trees in Florida and redbay trees throughout the southeastern USA. In a collaborative project, scientists from the University of Florida (Gainesville, FL), USDA-ARS (Miami, FL), and USDA-Forest Service (Washington, DC) studied the symbionts of three beetles recently introduced into Florida: Xylosandrus amputatus, Xyleborinus andrewesi, and Dryoxylon onoharaense. This was the first report describing the fungi carried by these foreign beetles. This information will help scientists understand the symbiotic relationships among invasive beetles and fungi, give insight into the evolution of pathogenicity in ambrosia fungi, and potentially help prevent future epidemics similar to laurel wilt.

Technical Abstract: Abstract In nearly every forest habitat, ambrosia beetles (Coleoptera: Curculionidae: Scolytinae, Platypodinae) plant and maintain symbiotic fungus gardens inside dead or dying trees. Some non-native ambrosia beetles aggressively attack live trees and damage tree crops, lumber, and native woody plant taxa by introducing phytopathogenic ambrosia fungi. Most established exotic species, however, do not cause any economic damage, and consequently are little studied. To determine the specificity and diversity of ambrosia symbionts, fungi were isolated from three non-native beetles in Florida: Xylosandrus amputatus, Xyleborinus andrewesi, and Dryoxylon onoharaense. Two of the beetles sampled each yielded a fungal species isolated with 100% frequency: Ambrosiella beaveri with X. amputatus and Raffaelea sp. with X. andrewesi. Both of these symbionts have been isolated previously from closely related ambrosia beetles, supporting the hypothesis that some beetles can carry monocultures of fungi, but the fungi may not be specific to single beetle species. No consistent fungi were isolated from Dryoxylon onoharaense, raising questions about its ecological habits. These results are now being used to test hypotheses and models explaining the evolution of pathogenicity within ambrosia fungi and invasion ability within exotic beetle-fungus complexes.