Walton, William E
Professor of Entomology and Department Vice Chair
- College of Natural and Agricultural Sciences
Research Specialization -
A major emphasis of research in my laboratory is to integrate studies of mosquito biology and ecology with the design of control methodologies for pestiferous and pathogen-transmitting mosquitoes in wetlands. Natural and constructed wetlands can be important developmental sites of mosquitoes. Multipurpose wetlands are being constructed to recycle precious water resources in arid southern California, to create habitat for wildlife, and to provide recreational activities for the ever increasing human population in the region. As design, construction, and operational criteria for man-made wetlands are established and evaluated, the development of effective mosquito abatement programs that protect the encroaching human population from disease and from nuisance biting of mosquitoes is necessary. A major emphasis of work in my laboratory is the design and implementation of novel and practical management strategies for wetland mosquitoes.
In addition to applied research on mosquito control, basic research on the population dynamics of larval mosquito populations, the interaction of mosquitoes with natural enemies, and the influence of vegetation on the temporal and spatial distribution of mosquito larvae in wetlands is ongoing. Much of our work focuses on the predominant vector of viruses causing human encephalitis and western equine encephalomyelitis in California, Culex tarsalis, and on the tule mosquito, Culex erythrothorax. Understanding the relative importance of factors regulating mosquito larval populations is critical for our continuing efforts to evaluate the effectiveness of large-scale mosquito abatement programs utilizing biological control agents, such as larvivorous fishes, and integrated control programs using bacterial larvicides and larvivorous taxa. Other ongoing studies in my laboratory include investigation of the behavior of larval and adult mosquitoes, the efficacy of larvivorous fishes against mosquitoes, the interactions among stream insects, the biogeography of freshwater flora and fauna and trophic interactions of freshwater food webs, and the evolution of resistance in mosquitoes to bacterial insecticides.
- BS Zoology 1978
- University of Rhode Island
- MS Zoology/Aquatic Ecology 1982
- University of Maryland
- PhD Zoology/Aquatic Ecology 1986
- University of Maryland
1992-1994 - Who's Who in Science and Engineering
IPM of vector and pest arthropods particularly mosquitoes.
Biogeography of freshwater flora and fauna.
Trophic interactions of freshwater food webs.
Van Dam, A. R. and W. E. Walton. 2008. The Effect of Predatory-fish Exudates on the Ovipositional Behaviour of Three Mosquito Species: Culex quinquefasciatus, Aedes aegypti and Culex tarsalis. Medical and Veterinary Entomology: 22:399-404.
Peck, G. W. and W. E. Walton. 2008. Effect of Mosquitofish (Gambusia affinis) and Sestonic Food Abundance on the Invertebrate Community within a Constructed Treatment Wetland. Freshwater Biology: 53: 2220-2233.
Heft, D. E. and W. E. Walton. 2008. Effects of the El Niño - Southern Oscillation (ENSO) Cycle on Mosquito Populations in Southern California. Journal of Vector Ecology 33(1): 17-29.
Pachón, R. T. and W. E. Walton. 2008. Effects of a Small-Scale Trout Farming Operation on Water Quality and Entomofauna of a Desert Stream in Southern California. Special Issue on “Stream Ecology and Low Flows.” International Journal of Ecological Economics and Statistics 12: 26-43.
Van Dam, A. R. and W. E. Walton. 2007. Comparison of Mosquito Control Provided by the Arroyo Chub (Gila orcutti) and the Mosquitofish (Gambusia affinis). Journal of the American Mosquito Control Association 23: 430-441.
Wirth, M. C., Y. Yang, W. E. Walton, B. A. Federici, and C. Berry. 2007. Mtx Toxins Synergize Bacillus sphaericus and Cry11Aa Against Susceptible and Insecticide-Resistant Culex quinquefasciatus. Applied and Environmental Microbiology: 73 (19): 6066-6071.
Walton, W. E. 2007. Larvivorous fish including Gambusia. In: "Biorational Control of Mosquitoes." (T. Floore, ed.). American Mosquito Control Association, Mount Laurel, NJ. Journal of the American Mosquito Control Association 23(2) Suppl. 184-220.
Walton, W. E., M. C. Wirth and P. W. Workman. 2007. Environmental factors influencing survival of threespine stickleback (Gasterosteus aculeatus) in a multipurpose constructed treatment wetland in southern California. Journal of Vector Ecology 32: 90-105.
Wirth, M. C., A. Zaritsky, E. Ben-Dov, R. Manasherob, V. Khasdan, S. Boussiba, and W. E. Walton. 2007. Cross-resistance spectra of Culex quinquefasciatus resistant to mosquitocidal toxins of Bacillus thuringiensis toward recombinant Escherichia coli expressing genes from B. thuringiensis subsp. israelensis. Environmental Microbiology. 9:1393-1401.
Popko, D. A., S.-K. Han, B. L. Lanoil, and W. E. Walton. 2006. A molecular ecological analysis of planktonic bacterial communities in constructed wetlands invaded by Culex (Diptera: Culicidae) mosquitoes. Journal of Medical Entomology 43: 1153-1163.
Peck, G. W. and W. E. Walton. 2006. The effect of bacterial food quality and density on growth and whole body stoichiometry of Culex quinquefasciatus and Culex tarsalis (Diptera: Culicidae). Journal of Medical Entomology 43: 25-33.
Sorensen, M. A., P. D. Jensen, W. E. Walton and J. T. Trumble. 2006. Acute and chronic activity of perchlorate and hexavalent chromium contamination on the survival and development of Culex quinquefasciatus Say (Diptera: Culicidae). Environmental Pollution 144: 759-764.
Sanford, M.R., K. Chan and W.E. Walton. 2005. Effects of inorganic nitrogen enrichment on mosquitoes (Diptera: Culicidae) and the associated aquatic community in a constructed treatment wetland. Journal of Medical Entomology. 42: 766-776.
Peck, G.W. and W.E. Walton. 2005. Effect of natural assemblages of larval foods on Culex quinquefasciatus and Culex tarsalis (Diptera: Culicidae) growth and whole body stoichiometry. Environmental Entomology. 34: 767-774.
Park, H.-W., D.K. Bideshi, M.C. Wirth, J.J. Johnson, W.E. Walton and B.A. Federici. 2005. Recombinant larvicidal bacteria with markedly improved efficacy against Culex vectors of West Nile virus. Amer. Journ. Trop. Med. and Hyg. 72: 732-738.
Wirth, M.C., J.A. Jiannino, B.A. Federici and W.E. Walton. 2005. Evolution of resistance to Bacillus sphaericus or a mixture of B. sphaericus + Cyt1A from Bacillus thuringiensis in the mosquito Culex quinquefasciatus (Diptera: Culicidae). J. Invert. Path. 88: 154-162.
Knight, R. L., W. E. Walton, G. F. O'Meara, W. K. Reisen, and R. Wass. 2003. Strategies for effective mosquito control in constructed treatment wetlands. Ecological Engineering 21: 211-232.
Walton, W. E. 2003. Managing mosquitoes in surface-flow constructed treatment wetlands. University of California, Division of Agriculture and Natural Resources. Davis, CA. Publ. No. 8117. 11 pp.
Thullen, J. S., J. J. Sartoris and W. E. Walton. 2002. Effects of vegetation management in constructed wetland treatment cells on water quality and mosquito production. Ecological Engineering 18: 441-457.
Walton, W. E. 2002. Multipurpose constructed treatment wetlands in the arid southwestern United States: Are the benefits worth the risks? pp. 115-123. In: J. Pries (ed.) Treatment Wetlands for Water Quality Improvement: Quebec 2000 Conference Proceedings. CH2M HILL Canada Limited, Pandora Press, Waterloo, ON.
Keiper, J. B., W. E. Walton and B. A. Foote. 2002. Biology and ecology of higher Diptera from freshwater wetlands. Annual Review of Entomology. 47: 207-232.
Wirth, M. C., A. Delécluse and W. E. Walton. 2001. Cyt1Ab1 and Cyt2Ba1 from Bacillus thuringiensis subsp. israelensis and subsp. medellin synergize Bacillus sphaericus against Aedes aegypti and resistant Culex quinquefasciatus (Diptera: Culicidae). Applied and Environmental Microbiology: 67: 3280-3284.
Wirth, M. C., W. E. Walton and B. A. Federici. 2000. Cyt1A from Bacillus thuringiensis restores toxicity of Bacillus sphaericus against resistant Culex quinquefasciatus (Diptera: Culicidae). J. Med. Entomol. 37: 401-407.