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

小行星9321759 能量和质量的约束不断相互作用，影响生物体的生态。没有什么比筑巢的热带海鸟更清楚地证明了这一点，那里有强大的选择来储存孵化转变的能量，并在这种炎热，恶劣的环境中保持水平衡。 在西北部的夏威夷群岛，楔尾剪水竞争筑巢的洞穴，而那些没有洞穴的（44%的人口）必须在地面上筑巢。如果这些地点几乎没有太阳辐射的保护，只有5-11%会产生小鸡。与海鸥不同，黑燕鸥和棕燕鸥都经常在阳光下筑巢，85%的巢都能孵出雏鸟。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，以便可以清楚地理解它们的相互作用。自1990年以来，PI一直在收集数据以建立这个模型，并希望在今年完成它，通过确定总的身体水分，水通量，以及在不同阴影量的巢穴中的剪水鸟，鸟和鸟的每日能量消耗。这些测定可以通过对1991年从注射氘或双标记水的鸟类中收集的血液样本进行实验室分析来进行。此外，PI希望从上述各种能量和水平衡变量的相对重要性中分析先前收集的膳食、鼻分泌物、尿液和粪便的组成。一些可能会阻止剪水鸟在炎热的小气候中成功筑巢的特征是长时间的孵化转变（9天），不经常饮用海水，以及胃油的形成减少了胃中可供饮水的空间。在这项研究中形成的相互作用的平衡模型，应该很容易修改，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. ***