Testosterone and Aggression in Birds

摘要: The familiar spring sound of birdsongs heralds the onset territory formation and a complex sequence interrelated events that make up breeding period. Such songs are an integral part repertoire aggressive behaviors males use to advertise defend territorial boundaries attract mates (Fig. 1). It is well established hormones, particularly testosterone, have stimulatory effects on aggression in reproductive contexts. prevailing "challenge" hy pothesis asserts testosterone corre late only during periods heightened interactions be tween males. Under more stable social conditions, according hypothesis, relation ships among maintained by other factors such as inertia, individual recognition status, boundaries, testoster one levels remain low. Recent re search has suggested ways which hypothesis should modified or extended. In this article we will con_ sider complexities their regulation, focusing specifically species differences behavior male birds models for multiple envi ronment, behavior. secretion interstitial cells testis controlled primarily glycoprotein, luteinizing hormone, secreted from anterior pituitary gland 2). Testosterone stimulates development secondary sex characteristics wattles, combs, spurs, cloacal protuberance (a copulatory organ),