Hormonal and Neuromuscular Control of Courtship Displays

The hormonal control of copulatory behaviors have been studies in many species. Many birds species engage in a variety of very complex courtship behaviors to gain access to members of the opposite sex. We know little about the hormonal and neuromuscular control of these behaviors. We are studying the Golden-collared manakin (Manacus vitellinus), a common bird of Panamanian rainforests. Male, but not female, manakins perform an elaborate courtship display that includes loud noises produced by the wings. We have found significant expression of androgen receptors in spinal motoneurons in these birds, including in motoneurons that innervate wing muscles. We have also identified 2 sexually dimorphic wing muscles in these birds. Presumably, androgens act on the muscles and spinal cord to control these courtship behaviors. We believe that these kind of steroid sensitive adaptations may be widespread in birds that perform similar visual and/or acoustic displays.