Dissertation Research: Effects of Mortality Risks on an Ontogenetic Niche Shift

9311196瑞安这个项目将调查动物为什么在孵化时孵化，以及孵化的时机如何影响它们的生存。一种两栖动物物种，agalychennis callidryas，在池塘上方的植物上产卵，当蝌蚪孵化时，它们就会掉进水里。蝌蚪能够在5天大的时候孵化，如果受到攻击，它们会这样做以躲避吃蛋的蛇。然而，未受干扰的蝌蚪通常会推迟几天孵化。它们继续在卵内生长，当它们孵化时，它们比较小的、早期孵化的蝌蚪更不容易受到水生捕食者的攻击。这项拟议的研究在胚胎和蝌蚪面临风险的背景下，研究了孵化过程中发育和行为灵活性对存活率的影响。许多动物在生命的不同阶段生活在不同的环境中，大多数动物都会孵化。动物做出这样的改变所面临的问题是普遍的，但在许多系统中，在自然条件下，只有两个阶段中的一个可以进行研究。这项关于孵化时间变化对卵和幼虫影响的研究将增加我们对行为和生态学的理解。它还将提供关于这种备受瞩目的热带雨林物种的生态的详细信息，特别是它在关键生命阶段与捕食者的相互作用。***L研究动物为什么会在孵化时孵化，以及孵化的时机如何影响！h h F%%(Times新罗马符号&amp；Arial#p“h Ryan摘要博士论文伊丽莎白·M·贝伦斯伊丽莎白·M·贝伦斯

9311196 Ryan This project will investigate why animals hatch when they hatch, and how the timing of hatching affects their survival. An amphibian species, Agalychnis callidryas, lays its eggs on plants overhanging ponds, and the tadpoles fall into the water when they hatch. Tadpoles are able to hatch as early as 5 days old and will do so to escape from egg-eating snakes, if they are attacked. Undisturbed tadpoles, however, usually delay hatching for several days. They continue growing, inside the egg, and when they hatch they are less vulnerable to aquatic predators than are the smaller, early-hatching tadpoles. The proposed research examines the effect on survival of developmental and behavioral flexibility in hatching, in the context of risks facing embryos and tadpoles. %%% Many animals live in different environments at different stages in their lives, and most animals hatch. The problems facing animals making such changes are general, but in many systems only one of the two stages is accessible to study under natural conditions. This study of the effects of changes in hatching time on both the eggs and larvae will add to our understanding of behavior and ecology. It will also provide detailed information on the ecology of this high profile rainforest species, particularly its interactions with its predators at a crucial life stage. *** l investigate why animals hatch when they hatch, and how the timing of hatching affects the ! ! ! ! !h h F % % ( Times New Roman Symbol & Arial # # p " h Ryan Abstract Doctoral Dissertation Elizabeth M. Behrens Elizabeth M. Behrens