Dissertation Research: Ontogenetic Ecomorphology of Escape Performance in Threespine Stickleback

贝尔9722134 湖泊种群的三棘鱼（Gasterosteus aculeatus）被认为是来自海洋种群，迁移到淡水繁殖。湖泊种群在形态和行为上与海洋条件不同。一些湖泊中的棘鱼以开放水域的浮游生物为食，经常暴露在捕食者面前。 在其他湖泊中，棘鱼以生活在底部的无脊椎动物为食，并经常栖息在植被覆盖的栖息地，以躲避捕食者。不同摄食方式的成虫表现出不同的体型，这可能与不同的觅食行为和捕食风险所青睐的游泳方式有关。目前对棘鱼幼鱼的觅食方式、运动方式和体型知之甚少。拟议的研究将量化变化（1）形态特征，影响捕食者逃避和觅食运动（使用新的方法，涉及形态标志）和（2）游泳能力（通过测量稳定和逃避游泳性能）在幼虫，少年，和成年人从不同的湖泊种群在阿拉斯加。脊椎数量的变化，这可能会影响回避游泳，也将进行分析。湖泊人口将与迁徙人口（假定的祖先形式）进行比较。将进行实地观察和胃内容物分析，以评估通过发展和种群之间的饮食，觅食行为和微生境使用的变化。

Bell 9722134 Lake populations of the threespine stickleback fish (Gasterosteus aculeatus) are believed to be derived from marine populations that migrate to fresh water to breed. Lake populations have diverged morphologically and behaviorally from the marine condition. Stickleback in some lakes feed on plankton in open water and are often exposed to predators. Stickleback in other lakes feed on bottom-living invertebrates and frequent vegetated habitats that provide refuge from predators. Adults that differ in feeding mode show body-shape variation that is probably related to the swimming styles favored by different foraging behaviors and predation risks. Little is known of foraging mode, locomotion, and body shape in larval and juvenile stickleback. The proposed study will quantify variation in (1) morphological features that affect predator evasion and foraging locomotion (using new methods involving morphological landmarks) and (2) swimming ability (by measuring steady and evasive swimming performance) in larvae, juveniles, and adults from different lake populations in Alaska. Variation in vertebral number, which may affect evasive swimming, will also be analyzed. Lake populations will be compared with a migratory population (the putative ancestral form). Field observations and stomach-content analyses will be conducted to assess variation through development and among populations in diet, foraging behavior, and microhabitat use.