Dissertational Improvement: Water and Energy Balance Constraints on the Nesting Ecology of Tropical Seabirds

9321759里克夫能量和质量的限制不断地相互作用，影响着生物体的生态。没有什么地方比筑巢的热带海鸟更清楚地证明了这一点，在这种炎热、恶劣的环境中，有很强的选择来储存孵化转移所需的能量，并保持水的平衡。在夏威夷群岛西北部，楔尾长尾鲨争相筑巢，而那些没有洞穴的人(占总人口的44%)必须在地面上筑巢。如果这些地点对太阳辐射几乎没有保护作用，那么只有5%-11%的人会生下小鸡。与海燕不同的是，黑燕鸥和褐燕鸥都会定期在阳光下筑巢，85%的巢都会产下雏鸟。为了更好地理解这种在炎热环境中筑巢能力的差异，PI构建了一个概念模型，将能量和物质平衡联系起来，以便清楚地了解它们之间的相互作用。自1990年以来，PI一直在收集数据来建立这个模型，并希望在今年完成这个模型，方法是测定不同遮荫量的鸟巢中剪毛虫、燕鸥和海龟的身体总水量、水通量和每日能量消耗。这些检测可以通过对1991年采集的禽类血液样本进行实验室分析来进行，这些血液样本是从注射了氘或双标记水的鸟类身上采集的。此外，PI希望分析食物的组成、鼻腔分泌物、尿液和粪便从上述相对重要性中收集的各种能量和水分平衡变量。在炎热的微气候环境中，一些可能会阻止剪毛鸟成功筑巢的特征包括孵化班次长(9天)，很少饮用海水，以及胃油的形成减少了胃可供水使用的空间。在这项研究中形成的相互作用平衡模型应该很容易被修改，以评估其他类型的竞争平衡对生物生态的影响。***

9321759 Ricklefs Both energy and mass constraints are continually interacting to influence the ecology of organisms. No where is this more clearly demonstrated than in nesting tropical seabirds where there is strong selection to store energy for the incubation shift and also to maintain water balance in this hot, harsh, environment. In the Northwestern Hawaiian Islands, Wedge-tailed Shearwaters compete for nesting burrows, and those without burrows (44% of the population) must nest on the ground surface. If these sites have little protection from solar radiation, only 5-11% will produce chicks. In contrast to shearwaters, both Sooty Terns and Brown Noddies regularly nest in the open sun and 85% of the nests produce chicks. To better understand this disparity in ability to nest in a hot environment, the PI has constructed a conceptual model that links energy and material balances so that their interactions can be clearly understood. Since 1990, the PI has been collecting data to build this model and hopes to finish it this year by determining the total body water, water flux, and daily energy expenditure of shearwaters, terns, and noddies at nest sites varying in amount of shade. These determinations can be made by laboratory analysis of blood samples collected in 1991 from birds injected with deuterium or doubly-labeled water. In addition, the PI hopes to analyze the composition of meals, nasal secretions, urine and feces previously collected from the above relative importance of various energy and water balance variables. Some characteristics that may prevent shearwaters from successfully nesting in hot microclimates are long incubation shifts (9 days), infrequent drinking of seawater, and the formation of stomach oils that reduce the amount of gastric space available for water. The model of interacting balances, formed in this study, should be easily modified to evaluate the effect of other types of competing balances on the ecology of organisms. ***