Repeated Climate-Linked Host Shifts Have Promoted Diversification in a Temperate Clade of Leaf-Mining Flies
Repeated climate-linked host shifts have promoted SPECIAL FEATURE diversification in a temperate clade of leaf-mining flies Isaac S. Winklera,b,1, Charles Mitterb, and Sonja J. Schefferc aDepartment of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613; bDepartment of Entomology, University of Maryland, 4112 Plant Sciences Building, College Park, MD 20742; and cSystematic Entomology Laboratory, Plant Science Institute, Agricultural Research Service, United States Department of Agriculture, 10300 Baltimore Avenue, Building 003, Room 231, BARC-West, Beltsville, MD 20705 Edited by Anurag A. Agrawal, Cornell University, Ithaca, NY, and accepted by the Editorial Board July 30, 2009 (received for review May 1, 2009) A central but little-tested prediction of ‘‘escape and radiation’’ ever, there is still little evidence on the degree to which changes coevolution is that colonization of novel, chemically defended host in either plant defense or insect ‘‘offense’’ promote diversifica- plant clades accelerates insect herbivore diversification. That the- tion (7). Progress on the insect side has come from several recent ory, in turn, exemplifies one side of a broader debate about the reports plausibly attributing an instance of significantly elevated relative influence on clade dynamics of intrinsic (biotic) vs. extrinsic insect diversity to a co-occurring shift to a new host taxon (5, 10, (physical-environmental) forces. Here, we use a fossil-calibrated 11). Any single instance of elevated diversification, however, molecular chronogram to compare the effects of a major biotic could reflect other influences that happen to be confounded factor (repeated shift to a chemically divergent host plant clade) with the host shift.
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