Entomology

Associate Professor and Graduate Director

Contact

Email: djh@umd.edu

Office Phone: 301-405-2401

Fax: 301-314-9290

Office Address: University of Maryland * Entomology Department * Plant Sciences Building * College Park, MD 20742

Teaching

Pollinators in Crisis (BSCI 120)
Introduction to Organismal Biology (BSCI 106)
Insect Population Genetics (BIOL 623)
Evolution of Insect Host Plant Interactions
Phylogeography

I am currently serving as the Entomology Department's Graduate Director.

Graduate Program Affiliations

BISI - Behavior, Ecology, Evolution, & Systematics (BEES)
Entomology

Research Interests

Our work emphasizes the interaction of genetic and ecological forces and the evolutionary consequences of those interactions. Using a combination of quantitative and molecular genetic approaches we study population genetic processes in pest insects to understand how they became pests, how they have evolved to counter our control efforts, and how we might use evolutionary thinking to better manage those pests. We are also using insects as models for understanding the genetic basis of adaptation and speciation. We have constructed genetic linkage maps for the Colorado potato beetle (Leptinotarsa decemlineata) and the pea aphid (Acyrthisiphon pisum). These maps have been used to identify quantitative trait loci (QTL's) that underlie variation in ecologically important traits in these insects. In particular, we are interested in the evolutionary process by which the Colorado potato beetle acquired potato (Solanum tuberosum) as a host plant (a great example of animal adaptation to a changed environment) and the means by which it has become resistant to many classes of insecticides. By understanding the genetic basis of insecticide resistance we will contribute both to the development of management plans to slow or prevent the adaptation of this pest to new insecticides and to the rational development of those new compounds. Our work on the pea aphid is also focused on the genetic basis of adaptation of an insect to its host plants. We have dissected the genetic changes underlying a dramatic host-plant associated schism among pea aphid populations. This host-plant mediated divergence has many of the elements necessary for sympatric speciation. In support of both of these projects are phylogeographic analyses of these species to help us understand some of the historical context of the contemporary processes that we observe. We are investigation issues in conservation genetics using experimental and phylogeographic approaches.

Recent Publications

Greenstone, M.H., Rowley, D.L., Weber, D.C., Payton, M.E. & Hawthorne, D.J. Feeding mode and prey detectability half-lives in molecular gut analysis: An example with two predators of the Colorado potato beetle. Bulletin of Entomological Research, in press.
Scheffer, S. and D. J. Hawthorne. Molecular evidence of recent formation of sympatric host races in the holly leafminer Phytomyza glabricola (Diptera: Agromyzidae): comparisons among multiple marker systems. Molecular Ecology, in press.
Miller, J. and D. J. Hawthorne. 2005. Durability of hitchhiking regions under strong selection in structured populations. Genetics. 171: 1353-1364.
Via, S. and D.J. Hawthorne. 2005. Back to the future: genetic correlations, adaptation and speciation. Genetica. 123: 147-156.
Kim, H-J., Hawthorne, D.J., Peters, T., Dively, G., and Clark, J.M. 2005. Application of DNA-based genotyping techniques for the detection of kdr-like pyrethroid resistance in populations of Colorado potato beetle field. Pestic. Biochem. Physiol. 81: 85-96
Hawthorne, D. J. 2003 Quantitative trait locus mapping of pyrethroid resistance in Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae). Journal of Economic Entomology. J. Econ. Entomol.96: 1021-1030.
Caldas, A. Hawthorne, D., and P. Barbosa. 2002. Isolation and characterization of microsatellite markers from Zale galbanata (Lepidoptera: Noctuidae) and amplification in other members of the genus. Molecular EcologyNotes 2: 296-297.
Via S., and D. J. Hawthorne. 2002. The genetic architecture of ecological specialization and its link to speciation in pea aphids. American Naturalist 159: S76-S88.
Hawthorne, D. J. 2001. AFLP-based genetic linkage maps of the Colorado potato beetle Leptinotarsa decemlineata and localization of pyrethroid resistance. Genetics 158: 695-700.
Hawthorne, D. J. and S. Via. 2001. Genetic linkage of ecological specialization and reproductive isolation in pea aphids. Nature 412: 904-907
Denno, R. F., D. J. Hawthorne, B. L. Thorne, and C. Gratton. 2000. Reduced flight capacity in British Virgin island populations of a wing-dimorphic insect: role of habitat isolation, persistence, and structure. Ecol. Entomol. 26:1-12
Hawthorne, D. J. 1999. Physiological not behavioral adaptation of leafminers to a resistant host plant: a natural selection experiment. Environ. Entomol. 28:
Hawthorne, D. J. 1998. Predicting insect adaptation to a resistant crop. Econ. Entomol. 91:565-571.
Via S, and D. J. Hawthorne. 1997. The genetics of speciation: Promises and prospects for quantitative trait locus mapping. In Endless forms: Species and speciation. Howard, D. J. and S. Berlocher, Eds.
Hawthorne, D.J., 1997. Ecological history and evolution in a new environment: habitat heterogeneity and insect adaptation to a new host plant. Evolution 51:153-162.
Hawthorne, D.J., and S. Via. 1994. Variation in performance on two grape cultivars within and among populations of grape phylloxera from wild and cultivated grapes. Entomol. exp. appl. 70: 63-76.
Hawthorne, D.J., and T.J. Dennehy. 1991. Reciprocal movement of grape phylloxera (Homoptera: Phylloxeridae)alates and crawlers between two differentially phylloxera-resistant grape cultivars. J. Econ. Entomol. 84: 230-236.

Education

B.S. & B.A. Kent State University, Kent, OH. Biology and Economics
M.S. North Carolina State University, Raleigh, NC. Entomology
Ph.D. Cornell University, Ithaca, NY. Entomology