Research
I work on the physiological ecology of insects and marine invertebrates. I and my group focus on fundamental physiological and biochemical aspects of metabolism. At its core, metabolism is the outcome of multiple, interacting fluxes of materials and energy between animals and their local environments. We are interested in how organisms and environments interact to affect those fluxes, the kinds of physiological and structural plasticity that organisms use in response to environmental variability, and the consequences of organism-environment interactions for animal ecology and evolution.
Three physiological ideas that currently organize my thinking.
Temperature-oxygen interactions: Variation in temperature affects components of metabolic systems in different ways. Some aspects of metabolism, like rates of biochemical reactions, are quite sensitive to temperature. Other aspects, like physical transport of oxygen, are relatively insensitive. Such mismatches in temperature sensitivty have interesting implications for how metabolic systems function in ectotherms undergoing rapid and dramatic changes in body temperature.
Oxygen-water tradeoffs: All terrestrial animals need oxygen, but getting it imposes costs-e.g., in building and maintaining structures for oxygen exchange and transport or in finding habitats with suitable oxygen levels. Another less obvious cost appears in the water budget: structures that transport oxygen into organisms-gills, lungs, skin, trachea, eggshells-also lose water to the environment. I am pursuing a basic set of questions about how oxygen-water tradeoffs affect organismal physiology, ecology, and evolution.
The physiology of extended phenotypes: Richard Dawkins made the case in his 1982 book that the phenotypic effects of alleles are not constrained just to the insides of organisms. Rather, they can also project away from the organism into its surrounding environment. The quintessential example is the beaver dam. A dam represents the outcome of decisions made by the beaver that built it, and those decisions can be influenced by the alleles the beaver contains. Because they are traceable in part to alleles, extended phenotypes can evolve. In a later book, Scott Turner (2000) proposed that extended phenotypes often act as organs of physiology--by tapping into potential energy gradients in nature or modifying fluxes of energy and materials between organisms and their environments. We are currently initiating a study (spear-headed by MS student Jon Sprague) on the physiology of an insect extended phenotype: the underground pupal chambers made by wandering larvae of many species.
Specific Research Projects
Ecological and evolutionary physiology of a sphinx moth, Manduca sexta, in North America
