I am interested in the general area of ecological and evolutionary physiology and endocrinology: the study of functional traits of organisms, their underlying (endocrine) regulation, and the significance of their variation in the natural world. I have investigated organismal energetics, thermal physiology, exercise performance capacities, and growth regulation, and I have included studies on thyroidal, gonadal, and adrenal endocrine systems. My general approach crosses traditional levels of biological organization from biochemical to behavioral and includes a blend of laboratory and field research. I stress the importance of field experiments solidly grounded in natural history. While the dissection of underlying mechanisms can require controlled laboratory conditions, the integration of complex physiological and behavioral interactions of interest in organismal biology can be fully understood only in the milieu of the natural environment. Only through field experiments can results be validated with reference to natural conditions.

My primary research project focuses on the attainment of adult body size, one of the most important quantitative traits of an organism. My work currently involves comparative and experimental studies on growth and sexual size dimorphism (SSD) in lizards, especially Sceloporus spp (Figure 1). This is a large genus with a well-defined phylogeny. Male-larger SSD is ancestral, but female-larger SSD has evolved in four clades. Many authors attribute patterns of SSD to adaptive hypotheses that invoke sexual selection on male body size and fecundity selection on female body size. However, the development of SSD is strongly subject to environmental conditions (Haenel and John-Alder, 2002), and available evidence overwhelmingly indicates that selection on body size can explain only a small fraction of the variability in SSD within lizards (Cox, Skelly, and John-Alder, 2003). Thus, we currently focus on the regulation of proximate mechanisms of SSD. Other ongoing projects include 1) integrative studies on stress, adrenal hormones, and adrenocortical cell function (with R. V. Carsia) and 2) comparative ecological analyses of Lyme disease risk (with R. S. Ostfeld, PI).

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Experience

Education

Professional Societies

American Association for the Advancement of Science
American Society of Animal Science
American Society of Ichthyologists and Herpetologists
Society of Behavioral Neuroendocrinology
Society for Integrative and Comparative Biologists
Society for the Study of Evolution

Representative Publications

Cox, R. M., S. L. Skelly, and H. B. John-Alder. 2005. Testosterone inhibits growth in juvenile male eastern fence lizards (Sceloporus undulatus): implications for energy allocation and sexual size dimorphism. Physiol. Biochem. Zool. In press.

Oppliger, A., M. S. Giorgi, A. Conelli, M. Nembrini, and H. B. John-Alder. 2005. Effect of testosterone on immunocompetence, parasite load and metabolic rate in the wall lizard Podarcis muralis. Canadian Journal of Zoology. In press.

Cox, R. M., S. L. Skelly, and H. B. John-Alder. 2003. A comparative test of adaptive hypotheses for sexual size dimorphism in lizards. Evolution. 57:1653-1669.

Carsia, R. V. and H. John-Alder. 2003. Seasonal Alterations in Adrenocortical Cell Function Associated with Stress-Responsiveness and Gender in the Eastern Fence Lizard (Sceloporus undulatus). Horm. Behav. 43:408-420.

Haenel, G. J., L. C. Smith, and H. B. John-Alder. 2003. Home range analysis in Sceloporus undulates. II. A test of spatial relationships and reproductive success. Copeia. 2003(1): 113-123.

Haenel, G. J., L. C. Smith, and H. B. John-Alder. 2003. Home range analysis in Sceloporus undulatus (eastern fence lizard). I. Spacing patterns and the context of territorial behavior. Copeia. 2003(1): 99-112.

John-Alder, H. B., Carsia, R. V., Smith, L. C., and Haenel, G. J. 2002. Seasonal and sexual variation in plasma corticosterone and adrenocortical cell function in eastern fence lizards (Sceloporus undulatus). Proceedings of the 21st Conference of European Comparative Endocrinologists, Bonn, Germany. Pages 141-146.

Haenel, G. J. and H. B. John-Alder. 2002. Experimental and demographic analyses of growth rate and sexual size dimorphism in a lizard, Sceloporus undulatus. Oikos. 96:70-81.

Zhou, T., H. B. John-Alder, J. S. Weis, and P. Weis. 2000. Endocrine disruption: thyroid dysfunction in mummichogs (Fundulus heteroclitus) from a polluted habitat. Mar. Environ. Res. 50:393-397.

de Fraipont, M., J. Clobert, H. John-Alder, and S. Meylan. 2000. Increased pre-natal maternal corticosterone promotes philopatry of offspring in common lizards Lacerta vivipara. J. Anim. Ecol. 69:404-413.

Smith, L. C. and H. B. John-Alder. 1999. Seasonal specificity of hormonal, behavioral, and coloration responses to within- and between-sex encounters in male lizards (Sceloporus undulatus). Horm. Behav. 36:39-52.

John-Alder, H., L. Seitz, and G. Haenel. 1997.
Ecological endocrinology of reptiles: hormonal causes and correlates of variation in exercise endurance in lizards. Pages 1661-1667. In Advances in Comparative Endocrinology. Proceedings of the XIIIth International Congress of Comparative Endocrinology, Yokohama, Japan. Editors: S. Kawashima and S. Kikuyama. Monduzzi Editore, Bologna, Italy.

John-Alder, H.B., S. McMann, L.S. Katz, A. Gross, and D.S. Green. 1996.
Social modulation of exercise endurance in a lizard (Sceloporus undulatus). Physiol. Zool. 69:547-567.

Steinberg, M.B., A.L. Finelli, R.W. Gerwien, and H.B. John-Alder. 1993.
Behavioral effects of thyroxine in a lizard (Ameiva undulata: Teiidae). Physiol. Zool. 66:148-165.

Gerwien, R.W. and H.B. John-Alder. 1992.
Growth and behavior of thyroid deficient lizards (Sceloporus undulatus). Gen. Comp. Endocrinol. 87:312-324.