Research Starter Grant

研究启动补助金

• 批准号: 0202676
• 负责人: Creagh Breuner
• 金额: $ 3.5万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-15 至 2004-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0202676&HistoricalAwards=false
• 关键词: Research; Starter; Grant

Responding to stressful events in the environment is a fundamentally important activity for all organisms. Within the stress response, there is a plasticity of glucocorticoid action, allowing for specificity in the response depending on life history strategy, reproductive stage, body condition, or even time of day. This proposal explores the mechanisms, environmental regulation, and functional consequences of this plasticity among three subspecies of the white-crowned sparrow (Zonotrichia leucophrys gambelii, Z. l. oriantha, and Z. l. pugetensis). The three subspecies have different distributions that are likely to affect the evolutionary pressures shaping the stress response. In particular, these sparrows breed at different elevations and latitudes and thus have breeding seasons that differ markedly in length. Gambelii is the northern-most subspecies, breeding in the arctic and sub-artic regions of North America. The breeding season is short (allowing only 1 clutch per season). Oriantha breed in sub-alpine meadows of the western United States. They can raise one and sometimes two clutches per season. Pugetensis breeds at low elevations in the Pacific Northwest and usually raises 2 or 3 clutches per season. This proposal explores the possibility that the length of breeding season has a strong evolutionary influence on how birds respond to stress. Specifically, in birds with time to raise only one or rarely two clutches, the fitness consequence of abandoning the nest may be substantially larger than in birds that can raise up to three clutches per season. Thus, animals with short breeding seasons should be less responsive to stressors, and therefore less likely to abandon their young. The stress response of each subspecies will be evaluated measuring basal and stress-induced corticosteroid responses to capture and handling, corticosteroid binding globulin levels (to estimate the bioavailability of glucocorticoids), and glucocorticoid receptor levels (to estimate the tissue-specific sensitivity to glucocorticoids).

对环境中的压力事件作出反应是所有生物体的一项基本重要活动。 在应激反应中，糖皮质激素的作用具有可塑性，可以根据生活史策略、生殖阶段、身体状况甚至一天中的时间来确定反应的特异性。 本研究旨在探讨白冠麻雀（Zonotrichia leucophrys gambelii，Z. L. oriantha和Z. L. pugetensis）。 这三个亚种有不同的分布，可能会影响形成压力反应的进化压力。 特别是，这些麻雀在不同的海拔和纬度繁殖，因此繁殖季节的长度明显不同。 甘贝利是最北的亚种，繁殖于北美的北极和亚北极地区。 繁殖季节很短（每个季节只允许1窝）。 Oriantha在美国西部的亚高山草甸繁殖。 他们可以提高一个，有时两个离合器每个赛季。 Pugetensis在太平洋西北部的低海拔地区繁殖，通常每个季节会繁殖2到3窝。 这项提议探讨了繁殖季节的长度对鸟类如何应对压力有很强的进化影响的可能性。 具体来说，在鸟类的时间，以提高只有一个或很少两个离合器，放弃巢的健身后果可能会大大大于鸟类，可以提高多达三个离合器每个赛季。 因此，繁殖期短的动物对压力的反应应该较小，因此不太可能放弃它们的幼崽。 将评价每个亚种的应激反应，测量基础和应激诱导的皮质类固醇对捕获和处理的反应、皮质类固醇结合球蛋白水平（以估计糖皮质激素的生物利用度）和糖皮质激素受体水平（以估计组织特异性对糖皮质激素的敏感性）。