Social-status, circulating levels of hormones, and competition for food in winter flocks of the White-throated sparrow
Social-status, circulating levels of hormones, and competition for food in winter flocks of the White-throated sparrow
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白喉麻雀冬季群体的社会地位、激素循环水平和食物竞争
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发表时间：
1988
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影响因子：
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通讯作者：
J. Wingfield
中科院分区：
文献类型：
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作者：
H. Schwabl;M. Ramenofsky;I. Schwabl;D. Farner;J. Wingfield
本文测定了越冬白喉麻雀血浆促黄体生成素（LH）、睾酮（T）、5α-二氢睾酮（DHT）和皮质酮（B）的含量。这一物种出现在两种颜色的变种，可区分的白色或棕褐色的中间冠条纹和不同的频率在生殖季节的竞争行为。在冬季，白喉麻雀形成的群体，其特点是由统治阶层，其中社会地位与性别和年龄，但不与冠色。LH和雄激素（T和DHT）的血浆水平的基础上，在大多数自由生活和圈养的鸟类和性别，年龄，形态或社会等级不相关。血浆睾酮水平没有增加圈养组，当侵略性的相互作用增加，由于实验操作的分布和食物量。这些结果表明：（1）在越冬阶段的显性-从属关系不是基于羽毛类型的不同攻击性，（2）它们不是由高等级鸟类血浆雄激素水平升高维持的。血浆浓度的B迅速增加，在女性和第一年的男性，但不是在成年男性的捕获压力的持续时间。由于成年男性的地位最高，看来较高的社会地位可能会抑制肾上腺对压力的急性反应。此外，B的基线水平在低级别的第一年女性中最高，在高级别的成年男性中最低。在圈养群体中，食物资源的数量和分布改变了B的水平。水平似乎是最可变的，非常高的一些鸟类的中级，竞争食物的竞争相互作用时最频繁。这表明食物分布的变化对那些社会地位不如高等级或低等级鸟类明确的鸟类的影响更大。
We measured plasma levels of luteinizing hormone (LH), testosterone (T), 5α-dihydrotestosterone (DHT) and corticosterone (B) in flocks of wintering white-throated sparrows. This species occurs in two colour morphs that are distinguishable by white or tan colour of the median crown stripe and differ in frequency of agonistic behaviour during the reproductive season. During winter, white-throated sparrows form flocks that are characterized by dominance hierarchies, in which social rank was correlated with sex and age, but not with crown colour. Plasma levels of LH and androgens (T and DHT) were basal in most free-living and captive birds and not correlated with sex, age, morph or social rank. Plasma levels of testosterone did not increase in captive groups, when aggressive interactions increased due to experimental manipulation of distribution and amount of food. These results suggest (1) that dominant-subordinate relationships during the wintering phase are not based on differential aggression of plumage types and (2) that they are not maintained by elevated plasma levels of androgens in high-ranking birds. Plasma concentrations of B increased rapidly with duration of capture stress in females and first-year males, but not in adult males. Since adult males were of highest rank it appears that high social status may restrain acute adrenal response to stress. Further, baseline levels of B were highest in low-ranking first-year females and lowest in high-ranking adult males. In captive groups, amount and distribution of food resources altered levels of B. Levels appeared to be most variable and very high in some birds of intermediate rank, when agonistic interactions in competition for food were most frequent. This suggests greater impact of change in food distribution on those birds, whose social status is less clear than that of high or low ranking birds.