Faculty Profiles

Diana K. Hews

Associate Professor

Ph.D., University of Texas at Austin

Phone: 812-237-8352
E-mail: dhews@indstate.edu
Office: Science Building 346

Editorial Board, Integrative and Comparative Biology (Oxford University Press), 2008-2013

Program Officer, Animal Behavior Society (Western Hemisphere), 2006-2009

North American Decision Editor, Animal Behaviour (Elsevier Press), 2002-2005

President, Wabash Valley Sigma Xi (Scientific Society), 2004-2005

Windows Media VideoResearch Video: Regular (8.67 mb) - Lo-Res (1.91 mb)

Research Interests: behavioral endocrinology; evolution of sexual dimorphism; color signals and social communication.

Sexual selection is responsible for many differences between males and females (sexual dimorphism), and it also can result in relatively discrete differences among males (Alternative Reproductive Tactics) that can be as extreme as male-female differences. Research in Dr. Hews' laboratory examines sexual selection at the interface between physiology and evolution. Dr. Hews seeks to identify the sources of selection favoring the evolution of such between- and within-sex differences, and how the underlying hormonal control of such differences has been shaped by natural and sexual selection. Differences in behavior, particularly aggression and territoriality, and in related morphological traits (body size, body mass, color signals) are the focus of work in the Hews lab.

Males of Sceloporus virgatus are an example of a species without blue abdominal patches that most other male Sceloporus express. Sexual dimorphism is ancestral for Sceloporus so this white abdomen represents a male loss of a secondary sexual trait.
© 2001 by David Sanders

A major area of research in Dr. Hews' lab involves the study of color signals used in social communication. A relatively new long-term project focuses on fence lizards (Sceloporus). Males of some Sceloporus species are "feminized": these species have evolutionarily lost the color signals that, in most Sceloporus, are expressed only in males. Males in these species are also less aggressive than males of typical species. In other species, females are "masculinized", expressing this normally "male-only" color trait and also elevated levels of aggression. Thus, Sceloporus species differ in the degree and nature of some aspects of sexual differentiation. Hormone manipulations can identify actions of early (pre-hatching and hatchling) and late (adult) differences in hormone levels in contributing to species differences in sexual differentiation. Comparing among species will identify how hormonal control mechanisms have evolved. Current work includes a histological description of color signal production in several Sceloporus species, and seeks to identify the cellular targets of hormone action.

Dr. Hews emphasizes studying animals in the wild, where the full array of social and environmental stimuli are present. Field studies or studies with captive animals in outdoor enclosures manipulate hormones, social conditions, or color signals to determine the effects on aggressive interactions, and, in longer-term studies, to document sources of selection acting on the color signals. Laboratory manipulations of hormones compliment field studies. Other major laboratory techniques include radioimmunoassay of plasma steroid hormone levels, and aromatase and reductase assays (enzymes that can convert certain steroid hormones to other, functional hormones), immunocytochemistry, and ELISA..

Selected Publications

In Preparation/In Review

Hews, D.K., Date, P., Hara E., and Castellano M.J. Field presentations of conspecific chemicals alter social display rates in the white-bellied Sceloporus virgatus but not in a more-visually oriented blue-bellied species.

Hews, D.K., Leache A.D., Shawkey, M.D. and Barnes D.J. Nanostructural and Fourier analysis of dermal iridophores in Sceloporus lizards with evolutionary variation in blue signaling patches.

Hara, .E, Anderson M. and Hews, D.K. Sex and species differences in brain distribution of androgen receptor immunoreactive cells in Sceloporus lizards differing in aggression.

Thaker, M., Hews, D.K. and Lima, S.L. Corticosterone mediation of antipredator responses in male lizards with alternative reproductive tactics. 

Kabange, Z. and Hews, D.K. Peripheral blood cell differential counts, cellular immune responses and humoral responses of Sceloporus undulatus lizards: age and sex differences.

Chakraborty, M., Kabange, Z,, and Hews, D.K. Effects of androgen manipulations on cellular and humoral responses to KLH immune challenges in adult Sceloporus undulatus males.

Hews, D.K. and Abell, A.J. Plasma levels of corticosterone and androgens following acute handling stress in male and female striped plateau lizards, Sceloporus virgatus.

Published/In Press

Calisi, R.M., Malone, J.H. and Hews, D.K. (in press) Female secondary coloration in the Mexican boulder spiny lizard (Sceloporus pyrocephalus) is associated with nematode load.  Journal of Zoology.

Baird, T.A. and Hews, D.K. (2007) Plasma levels of steroid hormones in territorial and non-territorial male collard lizards. Physiology & Behavior 92(4): 755–763.

Calisi, R.M. and Hews, D.K. (2007) Steroid correlates of multiple color traits in the spiny lizard, Sceloporus pyrocephalus. Journal of Comparative Physiology Series B: Biochemical, Systemic, and Environmental Physiology 177 (6):641-654.

Quinn, V.S. and Hews, D.K. (2005) Detection and response to conspecific chemical cues by ornate tree lizards (Urosaurus ornatus). Journal of Herpetology 39: 496-499.

Hews, D.K., M. Castellano, and E. Hara. 2004. Aggression in females is also lateralized: left-eye bias during aggressive courtship rejection in lizards. Animal Behaviour 68: 1201-1207.

Quinn, V. S. and D. K. Hews. 2003. Positive relationship between abdominal coloration and dermal melanin density in phrynosomatid lizards. Copeia 2003: 858-864.

Knapp, R., D. K. Hews, C. W. Thompson, L. E. Ray, and M. C. Moore. 2003. Environmental and endocrine correlates of tactic switching by nonterritorial male tree lizards (Urosaurus ornatus). Hormones and Behavior 43: 83-92.

Hews, D. K. and R. A. Worthington. 2001. Fighting from the right side of the brain: Left visual field preference during aggression in free-ranging male tree lizards (Urosaurus ornatus). Brain, Behavior and Evolution 58: 356-361.

Hews, D. K. and M. F. Benard. 2001. Negative association between conspicuous visual display and chemosensory behavior in two phrynosomatid lizards. Ethology 107: 839-850.

Quinn, V. S. and D. K. Hews. 2000. Signals and behavioural responses are not coupled in males: aggression affected by replacement of an evolutionarily lost colour signal. Proceedings of the Royal Society of London B 267: 755-758.