Hormones affect many aspects of the phenotype and behavior. Recent reviews have suggested that hormonal variaiton among individuals may dictate organismal fitness by first affecting phenotypic and functional variaiton, and then ultiamtely survival or reproduction. Because hormones also dramatically influence behavior (i.e., aggression), any study that examines hormones must adopt an integrative persepctive (behavior, morphology, and function). We are actively investigating how variation in hormones (testosterone and corticosterone) affect sexual signal size, behavior, and performance in lizards. We apply both manipulations (castrations, exogenous implants) and surveys of natural variation to examine how hormone levels affect all of these variables. We also apply studies of behavior (i.e., display behavior) to understand the interrelationships between hormone levels, behavior, and functional/morphological traits.

Relevant literature:

Husak JF, Irschick DJ, Meyers, JJ, Moore IT, Lailvaux SP.  2007.  Hormones, sexual signals, and performance of green anole lizards (Anolis carolinensis).  Hormones and Behavior.  52: 360–367.

Husak, JF, Irschick DJ, Henningsen J, Kirkbride K, Lailvaux SP, Moore IT.  2008.  Hormonal response of male green anole lizards (Anolis carolinensis) to GnRH challenge.  General and Comparative Endocrinology.  In review.