UCI Comp Phys



		Timothy J. Bradley Professor Comparative and Evolutionary Physiology 2007 Trip to Costa Rica Detailed travel plans to Costa Rica Powerpoint files: Costa Rica 1 Butterfly Farming

		E-mail: tbradley@uci.edu


*Osmoregulation in Saline-water and Blood-feeding Insects* A major area of study in my laboratory has been the characterization and elucidation of the mechanisms of osmoregulation in saline-water and blood-feeding insects. Saline-water insects are of interest from an ecological and physiological standpoint because of their capacities to osmoregulate in extreme aquatic habitats (environmental salinities up to three times seawater, pH 10, or water rich in magnesium or sulfate). Bloodfeeding insects must deal with extraordinary rates of diuresis (excreting up to five times their previous body volume in two hours). Both groups have an unusual problem for insects, namely excreting large amounts of sodium. All of these ecological peculiarities present very interesting physiological problems and these have been the subject of my studies. Beginning with my Master's work and continuing to the recent papers emanating from my laboratory I have elucidated the organs involved in ion transport, the ultrastructure of these tissues, directions and mechanisms of ion transport, hormonal control of ion transport, and the significance of osmotic regulation and ion transport processes in the distribution and ecological success of various saline-water groups. More recently I have also been interested in the evolution of saline tolerance in mosquitoes. This has lead to studies of the phylogenetic relationships in mosquito clades in which saline-water forms are common. Our recent physiological studies have concentrated on osmoconforming species and we are actively pursuing the mechanisms involved in the production and regulation of compatible osmolytes. *The Use of Selection Studies in Drosophila to Study Physiology* In 1990 I initiated a collaboration with Dr. Michael Rose, investigating the physiology of fruit flies, Drosophila melanogaster, that have undergone selection for delayed reproduction. As a result of such selection, the flies also show postponed senescence and will live to and reproduce at an age at which control populations have already died. These flies are an ideal system for investigating the genetic and mechanistic bases of postponed senescence. Dr. Rose is an evolutionary biologist and expert on the use of selection; my contributions have been in the area of insect physiology. We have been joined in these studies by Dr. Larry Muller, an evolutionary biologist and ecologist interested in the evolution of populations, and Dr. Allen Gibbs a comparative physiologist and biochemist. My laboratory characterized the energetic and metabolic changes that occur in these populations as a result of selection. The stress resistance of the flies exhibiting postponed senescence is greatly enhanced. This led us to initiate studies of the evolution of enhanced stress resistance at the population, genetic and physiological level. My contributions were in the elucidation of physiological differentiation in selected populations under selection, particularly with regard to metabolic, energetic and respiratory processes. This work continues to be a major focus of my lab and my two most recent NSF grants are directed at a further understanding of the processes of enhanced desiccation resistance in selected populations of fruit flies that have undergone selection for enhanced stress resistance. *Evolutionary Physiology* An underlying motivation for all of my work has been an understanding of the ecological significance of physiological mechanisms, and an understanding of the evolutionary processes by which physiological differentiation occurs in species. In recent years, I have approached these questions more rigorously and more directly using techniques that have come to be cumulatively described as Evolutionary Physiology. These include the use and interpretation of physiological data in the context of phylogenetic analysis and selection. I am among a small group of comparative physiologists who are making major contributions to this field and indeed are defining the paradigms and methods for a new subdiscipline in Physiology. In my laboratory we are pursuing studies of evolutionary physiology using both mosquitoes and Drosophila populations.

Ph.D. Zoology University of British Columbia May 1976 Vancouver, B.C., Canada M.S. Zoology University of Oklahoma August 1973 Norman, Oklahoma B.A. Biology Vanderbilt University January 1971 Nashville, Tennessee

National Merit Scholarship Finalist, 1966 Careers '75 Research Scholarship from the Province of British Columbia, 1974 NIH Postdoctoral Fellowship, 1978 1980 Fellow of the American Association for the Advancement of Science, Elected 1992 Excellence in Teaching Award, School of Biological Sciences, 1999

Hetz, S. & T.J. Bradley (2005) Insects breathe discontinuously to avoid oxygen toxicity, Nature. 433:516-519. Folk, D.G. & T.J. Bradley . (2005) Adaptive evolution in the lab: unique phenotypes in fruit flies comprise a fertile field of study. Int. Comp. Biol. 45:492-499. Gray, E. M. & T. J. Bradley (2005) The physiology of desiccation resistance in Anopheles gambiae and Anopheles arabiensis. Amer. J. Trop. Med & Hyg. 73(3):553-559. Bradley, T.J. & D.G. Folk. (2004) Analyses of Physiological Evolutionary Response. Physiol. Biochem. Zool. 77(1):1-9. Albers, M. & T.J. Bradley (2004) Osmotic regulation in adult Drosophila melanogaster during dehydration and rehydration. J. exp. Biol. 207: 2313-2321. Folk, D.G. & T.J. Bradley (2004) The evolution of recovery from desiccation stress in laboratory-selected populations of Drosophila melanogaster. J. exp. Biol. 207(15): 2671-2678. Gray, E. & T.J. Bradley. (2003) Metabolic rate in female Culex tarsalis (Diptera: Culicidae) : Age, size, activity and feeding effects. J. Med. Entomol. 40(6) 903-911. Patrick, M.L.: R. J. Gonzalez; C. M. Wood; R. W. Wilson; T. J. Bradley & A. L. Val (2002) The characterization of ion regulation in Amazonian mosquito larvae: evidence of phenotypic plasticity, population-based disparity and novel mechanisms of ion uptake. Physiol. Biochem. Zool. 75:223-236.