Riters Lauren V, Teague Donald P, Schroeder Molly B
Department of Zoology, University of Wisconsin, Madison, Wisc. 53706, USA.
Brain Behav Evol. 2004;63(3):141-50. doi: 10.1159/000076240. Epub 2004 Jan 15.
Reproduction results from a complex interplay among multiple factors including social stimuli, hormones, the brain, and an individual's physical characteristics. Male house sparrows (Passer domesticus) possess a bib of black feathers, or badge, that is associated with behaviors important for reproduction including courtship behaviors, copulation, and aggression. Such behaviors are controlled by testosterone activity within the central nervous system and are strongly influenced by social status and female behavior. To understand how multiple factors interact to coordinate reproductive activity we explored relationships among social status, badge size, gonad volume, and the volumes of brain regions involved in male courtship and dominance (HVC, robust nucleus of the archistriatum, and the medial preoptic nucleus). A trend toward a U-shaped relationship was observed between dominance status and badge size, with the most dominant and most subordinate males possessing the largest badges. Male vocal expression, copulation, and aggression were positively related to dominance status, but not badge size. In contrast, the volumes of HVC, the medial preoptic nucleus and the gonads related positively to badge size, but not dominance. Females preferentially approached large-badged males regardless of dominance status, but this interest translated into copulation for dominant rather than subordinate males, a finding possibly related to the observation that dominant males vocalized at higher rates than subordinates. Subordinate males that had large badges, attracted female interest, and possessed the neuroendocrine potential to perform courtship behaviors might have been prevented from doing so through social interactions with dominant males within the flock.
繁殖是多种因素复杂相互作用的结果，这些因素包括社会刺激、激素、大脑以及个体的身体特征。雄性家麻雀（Passer domesticus）有一块黑色羽毛的围兜，即羽饰，它与繁殖相关的重要行为有关，包括求偶行为、交配和攻击行为。这些行为由中枢神经系统内的睾酮活性控制，并受到社会地位和雌性行为的强烈影响。为了了解多种因素如何相互作用以协调繁殖活动，我们探究了社会地位、羽饰大小、性腺体积以及参与雄性求偶和支配行为的脑区（HVC、古纹状体粗核和内侧视前核）体积之间的关系。在支配地位和羽饰大小之间观察到一种U形关系趋势，最具支配地位和最从属的雄性拥有最大的羽饰。雄性的发声表达、交配和攻击行为与支配地位呈正相关，但与羽饰大小无关。相比之下，HVC、内侧视前核和性腺的体积与羽饰大小呈正相关，但与支配地位无关。无论支配地位如何，雌性都优先接近羽饰大的雄性，但这种兴趣转化为与占主导地位而非从属地位的雄性交配，这一发现可能与观察到的占主导地位的雄性发声频率高于从属雄性有关。羽饰大、吸引雌性兴趣且具有进行求偶行为的神经内分泌潜能的从属雄性，可能由于与群体中占主导地位的雄性的社会互动而无法这样做。
