Strategies for Overwintering by Hatchlings of Northern Turtles

北方海龟幼体的越冬策略

• 批准号: 9612562
• 负责人: Gary Packard
• 金额: $ 17.84万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 2001-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9612562&HistoricalAwards=false
• 关键词: Strategies; Overwintering; Hatchlings; Northern; Turtles

9612562 Packard This is a proposal to investigate the adaptive strategies for overwintering by hatchlings of five species of turtles inhabiting shallow lakes and marshes in the central and northern Plains. Hatchlings of two species (snapping turtle, Blanding's turtle) emerge from their subterranean nests in late summer, and then move overland to lakes or ponds where they establish residence and spend the winter. Hatchlings of two other species (ornate box turtle, yellow-bellied mud turtle) dig down through the bottom of their nests and spend their first winter of life deep in the soil. And hatchlings of the fifth species (painted turtle) remain inside their shallow, subterranean nests throughout the winter, and do not emerge from their nests until the soil thaws the following spring. Why do three different adaptive strategies for overwintering exist in the assemblage of turtles when neonates of all the species presumably would benefit from being able to remain for the entire winter inside their nest cavity? Research that will be performed over a period of 3 years will examine the roles of morphology, physiology, and behavior in enabling neonatal turtles to survive their first winter of life. Special attention will be given the integument, because the skin seems to be a barrier to the penetration of ice from frozen soil into body compartments of neonatal painted turtles but not to the penetration of ice into body compartments of neonates of the other species. Accordingly, hatchling painted turtles apparently survive over winter by exploiting a capacity for supercooling and remaining continuously unfrozen. Hatchlings of the other species, however, cannot exploit supercooling because their integuments seem not to resist the penetration of ice into body fluids from the environment. The absence of such a cutaneous barrier has caused hatchlings of other species to tap behavioral means for avoiding situations that could result in inoculation, freezing, and death. Thus, the common thre at of cold may have resulted in the evolution of three different adaptive strategies for overwintering by hatchlings in the same assemblage of turtles. The research there fore will elucidate the principle that evolution commonly produces multiple answers to the same general problem. ***

小行星9612562 本文拟探讨五种栖息于中国中部和北方平原浅水湖泊和沼泽地的龟类以幼体越冬的适应策略。 两种龟类（鳄龟和布兰丁龟）的幼龟在夏末从它们的地下巢穴中出来，然后从陆地上迁移到湖泊或池塘，在那里它们建立住所并度过冬天。 另外两种海龟（华丽箱龟、黄腹泥龟）的幼龟从巢穴底部向下挖掘，在土壤深处度过生命的第一个冬天。 第五种（彩龟）的幼龟整个冬天都呆在它们浅的地下巢穴里，直到第二年春天土壤解冻才从巢穴里出来。 为什么三种不同的越冬适应策略存在于海龟的组合中，而所有物种的新生儿都可能受益于能够在巢腔中度过整个冬天？ 这项为期3年的研究将研究形态、生理和行为在新生海龟度过生命第一个冬天中的作用。 特别要注意的是被，因为皮肤似乎是一个障碍，从冻土冰渗透到新生的彩龟的身体隔室，但不是渗透到其他物种的新生儿的身体隔室的冰。 因此，刚孵化的彩龟显然是通过利用过冷和持续解冻的能力来度过冬天的。 然而，其他种类的幼仔却不能利用过冷，因为它们的被皮似乎无法抵抗冰从环境中渗透到体液中。 这种皮肤屏障的缺乏导致其他物种的孵化物利用行为手段来避免可能导致接种，冷冻和死亡的情况。 因此，寒冷的共同威胁可能导致了三种不同的适应策略的进化越冬的孵化在同一组合的海龟。 因此，这项研究将阐明进化通常会对同一个一般问题产生多种答案的原理。 ***