Research Interests

Functional Morphology, Evolution, and Behavioral Ecology

Duncan Irschick is an integrative biologist interested in the evolution and ecology of animal performance. Animal performance traits have fascinated humans for generations, but there is still a great deal we don't know about why and how animals can perform their amazing feats, such as jumping, running, and biting. Why can some animals run so fast? How do lizards climb walls? Why are some animals so much stronger than humans? Whereas most research on animal performance has focused on the mechanistic underpinnings of performance (the "how"), Duncan's research explicitly examines performance traits in an evolutionary and ecological context. In this way, he examines not just the "how" of animal performance, but also the "why".

The research in his laboratory addresses the interface among organismal design, function, and ecology. Broadly, he is interested in the evolution of complex functional systems in all its facets. His research integrates microevolutionary and macroevolutionary approaches, and applies both experimental and descriptive approaches to understand the causes of, and ultimately the consequences of this diversity. Among others, some of the methods employed in his laboratory includes: phylogenetic comparative methods, ecological mark-recapture techniques, 2-D and 3-D kinematic analysis, analysis of kinetics (force dynamics), and analyses of hormones and morphology. While much of his research has focused on lizards as a model system, he also conducts studies with many other taxa, such as spiders, frogs, snakes, ungulates, salamanders, and mice, among others.

Some of the questions being addressed in the laboratory are:

• Which factors drive the evolution of complex functional systems, especially in the context of rapid evolution and climate change?
• Do morphology, behavior and habitat use co-evolve?
• Do hormone levels mediate fitness via their effects on morphology and performance?
• Which factors limit performance, both in terms of mechanistic factors, as well as behavior?
• Can we understand a species habitat use based on their functional capacities?
• How are sexual selection, physiology, and performance related?
• Why do animals vary in sexual signal size, and how is such variation related to performance, and ultimately, fitness?
• What limits the adhesive capacities of lizards with toepads, such as geckos?

The research in his laboratory takes an integrative approach by incorporating both field-based and laboratory-based methods to address these and other questions. In the field, he conducts ecological experiments, quantify processes of death and reproduction, and observe animals to understand their natural behavior. He conducts laboratory experiments to understand how behavioral aspects, such as male competition and female choice relate to performance capacity. Finally, he also take an explicitly mechanistic approach to understand how morphological variation translates into variation in performance, behavior, and habitat use.

Representative Publications

Irschick, D.J., Vitt, L.J., Zani, P., Losos, J.B. 1997. A comparison of evolutionary radiations in Mainland and West Indian Anolis lizards. Ecology, 78: 2191-2203.

Irschick, D.J., Jayne, B.C. 1999. Comparative three-dimensional kinematics of the hindlimb for high-speed bipedal and quadrupedal locomotion of lizards. Journal of Experimental Biology, 202: 1047-1065.

Irschick, D.J., Losos, J.B. 1999. Do lizards avoid habitats in which their performance is submaximal? The relationship between sprinting capabilities and structural habitat use in Caribbean anoles. The American Naturalist, 154: 293-305.

Irschick, D.J., Garland, T. Jr. 2001. Integrating function and ecology in studies of adaptation: Investigations of locomotor capacity as a model system. Annual Reviews of Ecology and Systematics, 32: 367-396.

Irschick, D.J., VanHooydonck, B., Herrel, A., Androsceu, A. 2003. Effects of loading and size on maximum power output and kinematics in geckos. Journal of Experimental Biology, 206: 3923-3934.

Ramos, M., Irschick, D.J., Christenson, T. 2004. Overcoming an evolutionary conflict: Removal of a reproductive organ greatly enhances locomotor performance. Proceedings of the National Academy of Sciences, 101: 4883-4887.

Lailvaux, S., Herrel, A., VanHooydonck, B., Meyers, J., Irschick, D.J. 2004. Performance capacity, fighting tactics, and the evolution of life-stage male morphs in the green anole Lizard (Anolis carolinensis). Proceedings of the Royal Society of London, B., 271: 2501-2508.

Irschick, D.J., Ramos, M., Buckley, C., Elstrott, J., Carlisle, E., Lailvaux, S., Bloch, N., Herrel, A., VanHooydonck, B. 2006. Are morphology->performance relationships invariant across different seasons? A test with the green anole lizard (Anolis carolinensis). Oikos, 114: 49-59.

Herrel, A., Huyghe, K., Vanhooydonck, B., Backeljau, T., Breugelmans, K., Grbac, I., Van Damme, R., Irschick, D.J. 2008. Rapid large scale evolutionary divergence in morphology and performance associated with the exploitation of a novel dietary resource in the lizard Podarcis sicula. Proceedings of the National Academy of Sciences, 105: 4792-4795.