The Smith Laboratory studies the evolution and physiology of sexually dimorphic communication behavior in South American ghost knifefishes. Ghost knifefish have electric organs that produce weak electrical signals used to detect nearby objects and to communicate. These signals provide an excellent system to study the evolution and physiology of sexual dimorphic behavior for several reasons. Electric communication signals are highly diverse both within and across species, and the magnitude of sex differences in signals varies across species.
Sex differences in electric communication behavior are regulated by gonadal steroid hormones (11-ketotestosterone and estradiol).
Finally, the neural circuits that control electric communication behavior are well-characterized and remarkably simple, which allows us to understand how hormonal and evolutionary changes in the brain and spinal cord are related to sex and species differences in behavior. We comparatively study the relationship between hormones, brain, and behavior by using a wide range of techniques including recording and playing back electric communication signals, hormone measurement and manipulation, immunohistochemistry, gene cloning and sequencing, molecular phylogenetics, and electrophysiology.