HISL - PEET Xyleborini

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This study will preserve and modernize the taxonomic expertise of tropical bark beetle (Curculionidae: Scolytinae) biologists through apprenticeship and the production of taxonomic catalogs, monographs, and phylogenetic hypotheses. Economic and academic interests comprise the intellectual merit of this study. In general, bark beetles function ecologically as decomposers of wood. However, some aggressive species and to a lesser extent benign species kill live trees, especially during periods of environmental stress. These pests cause severe economic and ecological losses, which often equate to millions of dollars. In addition, bark beetles comprise the majority of exotic insects intercepted at ports and those beetles that have escaped detection have greatly impacted forest economics and ecology. Many intercepted species are ambrosia beetles (Xyleborini), a poorly studied but diverse pantropical group (~ 1,200 species). Their haplodiploid sexuality and association with fungus increase their potential as exotic pests and also foster academic interest in their evolution. However, efforts to study and/or control this group are hampered by lack of taxonomic knowledge. This need to describe, classify and catalog ambrosia beetle diversity unfortunately coincides with a wordwide decline in scolytid taxonomists.

This study aims to increase understanding of Xyleborini taxonomy through production of: 1) regional monographs; 2) revisions of three taxa, Cnestus, Xylosandrus, and Xyleborinus; 3) phylogenetic analysis of genera including a robust sample of species; and 4) an electronic taxonomic catalog. First, few recent monographic regional reviews have been published. Many older scolytid collections remain unsorted and the process of documenting tropical biodiversity has greatly contributed to the backlog of specimen curation and identification. These shelved specimens will be studied within the context of a monograph of the Southeast Asian Xyleborini fauna. Also important to the health of North American forests and timber plantations is detailed knowledge of native and exotic xyleborine beetles. Many new exotic species are now residents of North America, and review of these beetles is overdo by 30 years. For both these regions, species will be described or redescribed with illustrations, identification keys will be constructed, and host and biological data will be listed. Interactive keys and electronic databases will also complement these taxonomic works. Second, a revision of Cnestus and Xylosandrus is necessary because they are paraphyletic with respect to each other. Xyleborinus contains economically important species, whose relationships are unknown. Further clarification of the generic and species limits will aid the identification of these potential pests. Third, a phylogenetic tree provides a means for the recognition of "natural groups" and for delimiting taxonomy given the criteria of monophyly. Thus, as a complement to alpha-level taxonomy, we will produce phylogenetic hypotheses for the 24 Xyleborini genera, including a robust sample of species. Finally, an extensive taxonomic catalog exists for all scolytid species. This indispensable resource contains nomenclatural, bibliographic, distributional, and host data for all species. However, its bound format makes expansion and amendments expensive and laborious. Thus, we will place the Xyleborini catalog data into an electronic format, which will provide a web-accessible and searchable database.

The direct training of two Ph.D. students in a collaborative atmosphere will preserve and foster scolytid taxonomic expertise. The remaining active bark beetle taxonomists have agreed to participate in this endeavor and mentor the students in collection-based systematic research. In total, training will include field and museum methods, computer databasing, species-level taxonomy including video-aided morphological analysis and contemporary phylogenetic analysis including delimitation character states. Formal course work, seminars, and frequent informal systematic group discussions will complement the specific goals of the project. Upon completion of their education, the students will be classically trained taxonomists and competent systematists skilled in modern techniques of databasing, and of character and phylogenetic analyses. Completion of this project will result in a better understanding and organization of tropical bark beetles and in the preservation and growth of a much-needed taxonomic expertise.

This web-site includes the above mentioned taxonomic revisions and other PEET products. These are in progress studies, thus please contact cognato@msu.edu if you wish to informally use the posted information. See individual pages for details of these studies.

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