Author
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O Donnell, Kerry |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 6/10/2010 Publication Date: 6/10/2013 Citation: O Donnell, K. 2013. Ambrosia beetle fungiculture [abstract]. Smithsonian Institute. Interpretive Summary: Technical Abstract: Ambrosia beetle fungiculture, as evidenced by the 11 independent origins and 3,500 species of ambrosia beetles, represents one of the most ecologically and evolutionarily successful symbioses. This presentation focuses on the discovery of a clade within the filamentous fungus Fusarium that is associated with ambrosia beetles in the genus Euwallacea (Coleoptera: Scolytinae). Ambrosia Fusarium Clade (AFC) symbionts are unusual in that some are plant pathogens that cause significant damage in naïve natural and cultivated ecosystems, and currently threaten avocado production in the United States, Israel, and Australia. Most AFC fusaria produce unusual club-shaped asexual spores that serve as a putative food source for their insect mutualists. AFC symbionts were abundant in the heads of four Euwallacea spp., which suggests that they are transported within and from the natal gallery in mandibular mycangia. Multilocus molecular phylogenetic analyses resolved the AFC as a strongly supported monophyletic group within the previously described Clade 3 of the Fusarium solani species complex (FSSC). Divergence-time estimates place the origin of the AFC in the early Miocene ~21.2 Mya, which coincides with the hypothesized adaptive radiation of the Xyleborini. Species-level lineages within the AFC consisted mostly of genetically identical individuals associated with specific insect hosts in defined geographic locations. Overall, the results suggest a strong evolutionary trend toward obligate symbiosis coupled with secondary contact and interspecific hybridization. |
