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To
view Jeff's CV, please click here (Microsoft
Word format).
Research
Interests:
Temperature influences physiological rates and therefore has wide ranging effects on animals’ behavioral decisions and ecologies. I am interested in thermoregulation and the continuum from ectothermy to endothermy across animal taxa. Thermoregulation may be achieved through metabolic, environmental, and behavioral means. Accessing the costs and benefits of thermoregulation and thermoregulatory strategies can elucidate the relative importance of organismal needs. Relative importance can be estimated by comparing resource allocation rates to mutually exclusive functions. I am also interested in how rates of resource gain and loss scale with body mass.
My dissertation investigates trade-offs for time allocation to mutually exclusive behaviors of thermoregulation and foraging for a central place forager, a brooding mother House Wren (Troglodytes aedon). It is difficult to obtain frequent core body temperatures for animals that shuttle to thermoregulate; this is not the case for altricial nestlings. The rapid ontogeny of nestling body mass and rates of metabolic heat production affect rates of temperature change. Times for the brood to cool and heat and amount of provisioning required to grow affect the dynamic between mother and brood. Rate constants for temperature change, temperatures of the nestlings' environments, and net metabolic heat production rates are estimated from temperature transients of frequent core body temperatures obtained under natural conditions. Complex temperature flux is well described with second-order negative exponential models. Parameter estimates are used to quantify times and energetic costs for thermoregulation. Predicted times for maternal behaviors and brood temperatures are evaluated by comparing them to field observations. The effect of temperature on nestling growth rate is tested with field manipulations of temperature with predictions made using a mass-based model for ontogenetic growth.
Key topics of investigation:
- Analysis methods for two types of second-order thermal transients
- Estimation of net metabolic heat production rate for altricial nestling during the ontogeny of thermogenesis
- The effects of body temperature on growth in altricial nestlings: A test of a general model for ontogenetic growth during the ontogeny of thermogenesis
- Optimization of brooding and foraging time by mothers of young altricial nestling
- Effective homeothermy and the cessation of brooding in altricial species
Publications
Kovatch, J.J., and Hainsworth, F.R. D
Development of endothermy in nestling House Wrens under natural conditions. Journal of Experimental Biology. (Submitted)
Kovatch, J.J., Hainsworth, F.R., and Pease, J. 2006. Analysis methods for two types of second-order thermal transients. Journal of Thermal Biology. 31: 247-255 [link to abstract]
Confernence Presentations:
Kovatch, J.J. and Hainsworth, F.R. 2005. Effect of increased temperature on growth rate in thermally dependent altricial nestlings. Meeting of the American Ornithologists’ Union, Santa Barbara, CA. Paper. [link to abstract]
Kovatch, J.J. 2003 and Hainsworth, F.R. 2003. Trade-offs for maternal provisioning of food and heat to young House Wren nestlings. Northeast Ecology and Evolution Conference, New Brunswick, NJ. Paper.
Kovatch, J.J. 2003 and Hainsworth, F.R. 2003. Trade-offs for maternal provisioning of food and heat to young House Wren nestlings. Joint Meeting of the Wilson Ornithological Society and the Association of Field Ornithologists, Delaware, OH. Paper.
Kovatch,
J.J., Voss, M.A., and Moll, K. 2002. Enhanced embryonic
development? Male incubation behavior in a breeding
colony of North American Barn Swallows. International
Society of Behavioral Ecology Conference, Montreal,
Canada. Poster.
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