Christy Bergeon Burns, Ph.D.

Postdoc / Lecturer
Ketterson and Demas Labs
Ecology, Evolution & Behavior Program
Department of Biology
Indiana University
1001 E 3rd St., Jordan Hall 142
Bloomington, IN 47405

E-mail: cbergeon AT indiana DOT edu

Curriculum Vitae

As of January 2013, I am beginning a postdoc at Louisiana State University. I will be examining the effects of the BP Deepwater Horizon oil spill on Seaside Sparrows, in collaboration with Drs. Sabrina Taylor, Phil Stouffer, and Stefan Woltmann.

Current Research

Circulating hormones can mediate the expression of several phenotypic traits within individuals at any given time. In birds, the gonadal steroid testosterone mediates many male reproductive trade-offs, simultaneously promoting traits such as sperm production, aggression, sexual behaviors and ornaments at the expense of immunity and parental care. A marked population of the Carolina junco has received extensive study and provided a wealth of information about testosterone-mediated phenotypic traits and trade-offs.

Such coordinated expression of a suite of testosterone-mediated traits may present evolutionary constraints under changing selection pressure.  Natural selection on one testosterone-mediated trait might result in the evolution of circulating testosterone levels, and by implication, the evolution of other traits mediated by testosterone.  However, in time selection might alter the relationship between testosterone and traits, potentially circumventing trade-offs and allowing a trait to evolve independently of other testosterone-mediated traits.

My research seeks to better understand how hormone-mediated characters evolve by examining the degree of integration and independence of testosterone-mediated traits across individuals and populations of dark-eyed juncos (J. hyemalis).

I conduct field research on white-winged juncos in the post-wildfire pine forest of the Black Hills near Custer, South Dakota. White-wings are the largest subspecies of dark-eyed junco, with larger patches of white on their tail as well as the unique white bars on their wings, presenting a great opportunity for comparative study. I am examining whether patterns of co-variation between hormonal responsiveness and hormonally mediated behavior identified in the Carolina junco population hold up in the divergent white-winged junco.

Moreover, my research addresses whether variation in endocrine mechanisms may help to explain variation in hormone-phenotype relationships across subspecies. Specifically, I am examining the hypothalamo-pituitary-gonadal (HPG) axis responsible for testosterone release, asking where along this axis the variation among individuals and populations arises. Using qPCR, I am also beginning to examine neuroendocrine response mechanisms in dark-eyed juncos, asking whether individual or population differences in hormone signaling (secretion) co-vary with target tissue sensitivity (receptors).