Arthur E. Weis

picture of Arthur E. Weis

Professor, Ecology & Evolutionary Biology
School of Biological Sciences

PH.D., University of Illinois

Phone: (949) 824-2241
Fax: (949) 824-2181

University of California, Irvine
307, 384 SH
Mail Code: 2525
Irvine, CA 92697
Research Interests
Plant ecological genetics, plant-insect interactions
National Science Foudation Postdoctoral Fellowship, 1981
Research Abstract
My lab works on the ecological genetics of plants. We have projects to probe the short-term evolution of plant populations to their local physical and biotic environments.

1) Evolution of Flowering Time: When the shift from vegetative growth to reproduction occurs too early, plants have few resources to make progeny. When the shift is too late they do not have enough time to mature their progeny. My lab is investigating this trade-off using local B. rapa populations.

Variation in flowering time induces phenological assortative mating—early bloomers tend to mate with other early bloomers while late mates with late—and this has interesting consequences for short-term evolution. The genetic variance for flowering time will be inflated by assortative mating, and this may accelerate its response to natural selection. I have a number of experiments underway, with post-doc Dr. Steven Franks. We are evaluating the degree of genetic variance inflation in B. rapa, and testing if this inflation is sufficient to allow evolutionary tracking of the expansion and contraction of the growing season caused by el Niño cycles.

In addition, I am looking at the role of phenological assortative mating in the maintenance of local adaptation. My collaborator, Dr. Gretchen LeBuhn of San Francisco State University, are studying a steep cline in B. rapa flowering time to determine how strongly phenological assortment counters the homogenizing effects of gene flow—enough to maintain the genetic differences among populations.

2) Crop/Weed Hybridization and the Escape of Transgenes: Some crop species are grown in proximity to their weedy wild relatives. This creates the danger of an engineered gene moving into the weed population.

In collaboration with with Dr. Michael Hochberg of the University of Montpellier II, in France, I am working on models to assess the relative importance of factors that can determine the rate of spread for resistance transgenes into natural populations. This theoretical work is coordinated with experiments on hybridization between B. rapa and Canola (Brassica napus).

3) Plant Tolerance to Herbivory: Although a few plant species recover completely from seemingly devastating herbivore attack, most do not. We are using an artificial evolution protocol to see if the evolution of improved tolerance comes at the expense of reduced general growth performance. This work is in coloration with Dr. Ellen Simms at the University of California Berkeley.
Ellis, G.A., A.E. Weis and B.A. Gaut. 2006. Evolutionary radiation of “stone plants” in the genus Argyroderma (Aizoaceae): unraveling the effects of landscape, habitat and flowering time. Evolution (in press).
Franke, D.M., A. Ellis, M. Dharjwa, M. Freshwater, A. Padron, M. Fujikawa. and A.E. Weis. 2006. A steep cline in flowering time for Brassica rapa in southern California, I: Population-level variation in the field and the greenhouse. International Journal of Plant Sciences (in press).
Hawkins, B.A., J.A.F. Diniz-Filho and A.E. Weis. 2005. The mid-domain effect and diversity gradients: is there anything to learn? American Naturalist 166:000-000.
Weis, A.E. 2005. Direct and indirect assortative mating: a multivariate approach to plant flowering schedules. Journal of Evolutionary Biology 18:536-546.
Weis, A.E., and T. M. Kossler. 2004. Genetic variation in flowering time induces phenological assortative mating: quantitative genetic methods applied to Brassica rapa. American Journal of Botany 91: 825-836.
Winterer, J. and A.E. Weis. 2004. Stress-induced assortative mating and the evolution of stress resistance. Ecology Letters 7: 785-792
Weis, A.E. 2005. Assessing the ecological fitness of recipients, in, G. poppy and M. Wilkinson (eds.), Gene Flow from Genetically Modified Crops, Blackwell, Sheffield, UK.
Vacher, C., A.E. Weis, D. Herman, T. Kossler, C. Young and M. Hochberg. 2004. Impact of ecological factors on the initial invasion of Bt transgenes into wild populations of birdseed rape (Brassica rapa). Theoretical and Applied Genetics 190: 806-814.
Weis, A.E., J. Winterer, T.A. Kossler, C.Y. Young, C. Vacher and G.L. LeBuhn. 2004. Phenological assortative mating in plants: causes and consequences of its inherent frequency-dependence. Evolutionary Ecology Research 7:161-181.
Weis, A.E., E.L. Simms and M.E. Hochberg. 2001. Will plant vigor and tolerance be genetically correlated?: Effects of intrinsic growth rate and self-limitation on regrowth Evolutionary Ecology 14:331-352.
Weis, A.E., and M.E. Hochberg. 2000. The diverse effects of intra-specific competition on selection for resistance: A model and its predictions. American Naturalist 156:276-292.
Krupnick, G.A., A.E. Weis and D.R. Campbell. 1999. The consequences of floral herbivory for pollinator service to Isomeris arborea. Ecology 80:125:134
Krupnick, G.A. and A.E. Weis. 1999. Gametes gone to waste: Effects of floral herbivores on male and female reproductive success in Isomeris arborea. Ecology 80:135-149.
Richter, K.S. and A.E. Weis. 1998. Inbreeding and outcrossing in Yucca whipplei: consequences for the reproductive success of plant and pollinator. Ecology Letters 1:21-24.
Weis, A.E. and W.G. Abrahamson. 1998. Just lookin’ for a home. Natural History 107(7):60-63.
Abrahamson, W.G., and A.E. Weis. 1997. Evolutionary Ecology across Three Trophic Levels: Goldenrods, Gallmakers and Natural Enemies. Princeton Monographs in Population Biology, Princeton University Press.
Weis, A.E. 1996. Variable selection on Eurosta's gall size, III: Can a response to selection be detected? Journal of Evolutionary Biology 9:623-640.
Richter, K.S. and A.E. Weis. 1996. Differential abortion in yucca. Nature 376:557-558.

National Science Foundation DEB-0345030 —Population Biology Program; Exploring the intensity and consequences of phenological assortative mating in plants. 2004-2008. ($459,000.00).
National Science Foundation DEB-0440595 — Research Experience for Undergraduates Program; Supplemental Grant for Undergraduate Research Assistantships. 2004-2005. ($5,000.00).
School of Biological Sciences, University of California-Irvine—Potential for introgression between Canola and a weedy wild relative. 2003 ($6,400.00)
National Science Foundation DEB-9815873—Population Biology Program; Constraints on the Evolution of Plant Tolerance. (In collaboration with Ellen Simms) 1999-2003. ($390,000.00).
Professional Societies
European Society for Evolutionary Biology
Botanical Society of America
American Association for the Advancement of Science
Research Centers
Evolutionary Genetics
Plant Evolutionary Ecology
Center for Experimental Evolution
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