Day Lainy B, McBroom Jennifer T, Schlinger Barney A
Department of Physiological Science, University of California, 621 Charles E. Young Dr. S., Los Angeles, CA 90095-1527, USA.
Horm Behav. 2006 Feb;49(2):223-32. doi: 10.1016/j.yhbeh.2005.07.006. Epub 2005 Aug 8.
In order to attract females, male golden-collared manakins gather in leks and perform a complex display consisting of acrobatics accompanied by loud "wingsnapping". During this display, males show off their yellow beard and yellow, black, and green plumage that is striking in comparison to the dull green plumage of young males and females. We investigated the role of testosterone (T) in activating the display of manakins and in stimulating the growth of the adult male plumage. T regulates song, copulation, and territorial aggression in temperate species. In tropical species, however, T levels can be relatively low year round, which has raised questions about the involvement of T in courtship display and male aggression in these species. In neither temperate nor tropical species has the role of hormones in the shift from juvenile to adult plumage been well studied. Therefore, we implanted green-plumaged birds and adult males with either a T pellet or an inert pellet (controls) and observed the display behaviors of these birds in the field and in captivity. In captive birds, we also plucked feathers from sexually dimorphic regions and observed color and regeneration rate of new feathers. We found that birds implanted with T increased several display behaviors compared to controls. All plucked feathers grew back the same color as prior to treatment; however, we observed some differences in feather growth rate between T-treated birds and controls.
为了吸引雌性，雄性金领侏儒鸟会聚集在求偶场中，并进行一种复杂的展示行为，包括杂技动作并伴有响亮的“拍翅声”。在这种展示过程中，雄性会炫耀它们黄色的胡须以及黄色、黑色和绿色的羽毛，与幼年雄性和雌性暗淡的绿色羽毛相比，这些羽毛十分醒目。我们研究了睾酮（T）在激活侏儒鸟展示行为以及刺激成年雄性羽毛生长方面的作用。T调节温带物种的鸣叫、交配和领地攻击行为。然而，在热带物种中，T水平全年可能相对较低，这引发了关于T在这些物种的求偶展示和雄性攻击行为中所起作用的疑问。在温带和热带物种中，激素在从幼年羽毛向成年羽毛转变过程中的作用都尚未得到充分研究。因此，我们给羽毛为绿色的鸟和成年雄性植入了T丸或惰性丸（对照组），并在野外和圈养环境中观察这些鸟的展示行为。对于圈养的鸟，我们还从具有性别二态性的区域拔下羽毛，并观察新羽毛的颜色和再生速度。我们发现，与对照组相比，植入T的鸟增加了几种展示行为。所有拔下的羽毛重新长出的颜色与处理前相同；然而，我们观察到接受T处理的鸟和对照组在羽毛生长速度上存在一些差异。
