DISSERTATION RESEARCH: Implications of Adult Incubation Behavior on Embryo Growth and Metabolism

论文研究：成虫孵化行为对胚胎生长和代谢的影响克里斯托弗·r·奥尔森和卡罗尔·m·弗莱奇奥瓦州立大学鸟类孵卵必须在维持胚胎生长所需的蛋温和花时间觅食之间分配时间。人们早就知道，鸡蛋成功孵化的热条件范围很窄。然而，许多小型鸣禽的蛋在成鸟离开巢去觅食时，经常经历很大的热波动，但蛋还是成功孵化了。鸟类的孵化行为各不相同。有些物种双亲都孵蛋，卵很少冷却。在其他物种中，只有雌性孵化，当雌性离开巢穴去觅食时，卵会间歇性地冷却。这表明一些鸟类胚胎已经进化出了热耐受性，也就是说，它们能够在降温的情况下存活下来，仍然保持正常的生长。本研究的总体目标是描述卵的热分布与孵化成虫的孵化策略之间的关系。它将包括在实验室进行的两项关于胚胎对间歇性冷却的生理和发育反应的实验和一项实地实验。1. 在模拟冷却和复温期间，将对斑胸草雀（Taeniopygia guttata）卵的代谢进行研究，以确定胚胎对不同程度的间歇性冷却的代谢反应。2. 在整个发育过程中，将检查间歇性冷却的表型和生存后果。然后将这些知识扩展到野外，以研究成年和胚胎鸟类所承受的约束和限制。3. 将增加或减少家鹪鹩（穴居人）卵的冷却速率，并监测成虫的反应。当降温速率增加时，预计成虫会通过转向有利于卵的行为来补偿，主要是花更多的时间在巢上。然而，当降温速率降低时，成年人应该花更多的时间寻找食物。结合这三个实验的结果将有助于理解卵热生理如何限制成虫的孵化行为和繁殖生物学。

Dissertation Research: Implications of Adult Incubation Behavior on Embryo Growth and MetabolismChristopher R. Olson and Carol M. VleckIowa State UniversityBirds incubating eggs must allocate time between maintaining egg temperatures required for embryonic growth and spending time foraging for food. It has long been known that the range of thermal conditions for eggs to hatch successfully is narrow. However, the eggs of many small songbirds frequently undergo wide thermal fluctuations when the adults leave their nests to forage, and yet the eggs hatch successfully. Birds vary in their incubation behaviors. In some species both parents incubate and eggs seldom cool. In other species only the female incubates, resulting in episodic cooling of the eggs when the female leaves the nest to forage. This suggests that some avian embryos have evolved thermal tolerance, that is, they are able to survive episodes of cooling and still maintain normal growth. This study's general goal is to describe the relationship between the thermal profile of the eggs and the incubation strategy of the incubating adult. It will incorporate two experiments carried out in the lab on the physiological and developmental responses of embryos to episodic cooling and one field experiment. 1. Metabolism of zebra finch (Taeniopygia guttata) eggs will be examined during simulated cooling and rewarming bouts to define the embryonic metabolic response to different degrees of episodic cooling. 2. The phenotypic and survival consequences of episodic cooling throughout development will be examined. This knowledge will then be extended to the field to study constraints and limitations that both adult and embryonic birds endure. 3. Cooling rates of house wren (Troglodytes aedon) eggs will be increased or decreased and adult response monitored. When cooling rates are increased, adults are predicted to compensate by shifting to behaviors that benefit the eggs, mainly spending increased time on the nest. However, when cooling rates are decreased, adults should spend more searching for food. Combining the results of these three experiments will aid in understanding how egg thermal physiology places limits on adult incubation behavior and breeding biology.