Gwen C. Bachman
Ph.D. University of California at Los Angeles, 1992
231 Manter Hall
My research explores the influence of energy supply and demand on animal behavior. Energy flow through organisms has long been recognized as a central process underlying ecological interactions and evolutionary adaptation. More recently, behavioral energetics, which examines how behavior affects and is affected by energy flow through an organism, has become an important theme in behavioral ecology. The rate and amount of net energy acquisition and storage are clearly linked to production, therefore it is reasonable to propose energetic 'costs' and physiological limits as selective forces affecting the expression of behavioral strategies. To investigate the influence of energy intake, storage, and expenditure on animal decision making I combine experimental field studies of behavior with in vivo estimates of body composition and energy expenditure. My past research examines aspects of foraging decisions and mating tactics in birds and mammals.
Currently, I’m addressing questions in the areas of stress physiology and endocrinology, eco-immunology, metabolic physiology, microhabitat choice, and reproductive success in birds, mammals and reptiles.
I currently have an opening for a graduate student to conduct research on the behavior and physiology of ornate box turtles Terrapene ornata. We have a marked population at UNL’s Cedar Point Biological Station. Turtles are a long-lived species with low reproductive rates and limited migratory abilities. Our aim is to define physiological and behavioral traits that are consistent with animals that can survive extended periods of low resource availability, but will delay reproduction until conditions improve. Species with these life history characteristics may be particularly challenged by climate change, or, through behavioral or physiological compensation, they may be able to adapt within their lifetime. To better understand the impact of long-term climate change on box turtle populations, we are collecting data to describe relationships between temperature, behavior, physiology, and reproductive output. Key physiological variables that are currently being examined are the metabolic rates associated with hibernation, prey capture, digestion, activity, and resting at different temperatures. We are also conducting observations of activity levels in relation to temperature extremes, and will conduct experiments to probe potential trade-offs between growth and reproduction. These data together with habitat variables will become part of a model that predicts the impact of warming on energy requirements, survival and reproduction in this species. The field station can provide modest graduate research funds and undergraduate assistance is available. The desire and ability to work under very warm field conditions is necessary as is a background in physiology and ecology. Prior experience with reptiles is desirable but not essential.
- Bachman GC. 2000. Changes in leukocyte counts in hibernators from spring through summer. AMERICAN ZOOLOGIST 40 (6): 933-933.
- Bachman, G., F. Widemo. 1999. Relationships between body composition, body size, and alternative reproductive tactics in a lekking sandpiper, the Ruff (Philomachus pugnax). Functional Ecology: 13:411-416.
- Bachman, G.C., Chappell, M.A. 1998. Energetic cost of begging in house wrens (Troglodytes aedon). Animal Behaviour 55:1607-1618.
- Chappell MA, Bachman GC.1998. Exercise capacity of House Wren nestlings: Begging chicks are not working as hard as they can. AUK 115 (4): 863-870.
- Chappell, M. A., Bachman, G. C. and Hammond, K. A.1997. The heat increment of feeding in house wren chicks: Magnitude, duration, and substitution for thermostatic costs. Journal of Comparative Physiology B 167: 313-318.
- Bachman, G.C. and S.L. Vehrencamp. 1995. "Ecological Energetics of Terrestrial Vertebrates" , p. 549-565 in "Encyclopedia of Environmental Biology", Academic Press.
- Bachman, G.C. 1994. Food restriction effects on the body composition of free-living ground squirrels. Physiological Zoology 67:756-770.
- Bachman, G.C. 1993. The effect of body condition on the trade-off between vigilance and foraging in Belding's ground squirrels. Animal Behaviour 46:233-244.