Molecular Ecology and Evolution
Sipes, S.D. , Danforth, B.N. , Brady, S.G. , Fang, J. .
What can the phylogeny of the bees tell us about Darwin's Abominable Mystery?
TO Darwin, the rapid emergence and early diversification of the angiosperms was an “abominable mystery”. Among the most important traits attributable to the explosive radiation of the angiosperms is animal-mediated pollination. Bees are a diverse group (>16,000 species) of obligate feeders on floral resources that originated in early to mid-Cretaceous, roughly in synchrony with the angiosperms. Bees are currently the most important pollinators of many angiosperms, and understanding the co-evolutionary history of bees and angiosperms requires a well-supported phylogeny of the bees as well as of the angiosperms. Until now, relationships among the seven bee families were unresolved. We reconstructed a robust phylogeny of the bees at the family and subfamily level using a data set of six genes (>5000 nucleotide sites) plus morphology (109 characters). The molecular data set included protein-coding (elongation factor-1 alpha, RNA polymerase II, LW rhodopsin, and wingless wg-1) as well as ribosomal (28S and 18S) nuclear gene data. Analyses of both the DNA data set and the DNA+morphology data set by parsimony and Bayesian methods yielded a single, well-supported family-level tree topology that places the short-tongue bee family “Melittidae” as a paraphyletic group at the base of the phylogeny of bees. This topology (“Melittidae+ Long tongue bees basal”) differs from a traditionally propounded alternative topology placing Colletidae as the basal lineage of bees. Our results have important implications for understanding host-plant evolution and the early diversification of flowering plants. The earliest branches of bee phylogeny include lineages that are predominantly host-plant specialists. Our results suggest the possibility that host plant specificity may be a plesiomorphic character in bees, and that relationships with specialist bees may have been a factor in the early stages of angiosperm diversification.
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Bee Phylogeny Website
1 - Southern Illinois University Carbondale, Plant Biology and Center for Ecology, 1125 Lincoln Dr., mail code 6509, Carbondale, Il, 62901, USA
2 - Cornell University, Department of Entomology, Comstock Hall, Ithaca, NY, 14853, USA
3 - Smithsonian Institute, Department of Entomology and Laboratories of Analytical Biology, Suitland, Maryland, 20746, USA
4 - University of Arizona, Department of Physiology, P.O box 245051, Tucson, AZ, 85742, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 31st, 2006
Time: 1:30 PM