Dissertation Research: Ontogenetic Ecomorphology of Escape Performance in Threespine Stickleback

三刺棘鱼（Gasterosteus aculeatus）的湖泊种群被认为是由海洋种群迁移到淡水繁殖而来。湖泊种群在形态和行为上都与海洋种群不同。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。其他湖泊的棘鱼以生活在海底的无脊椎动物和常见的植被栖息地为食，这些栖息地为它们提供了躲避捕食者的避难所。不同摄食方式的成虫表现出不同的体型差异，这可能与不同的觅食行为和捕食风险所偏好的游泳方式有关。棘鱼幼虫和幼鱼的觅食方式、运动和身体形状所知甚少。该研究将量化(1)影响捕食者逃避和觅食运动的形态学特征（使用涉及形态学标志的新方法）和(2)来自阿拉斯加不同湖泊种群的幼虫、幼鱼和成鱼的游泳能力（通过测量稳定和逃避游泳表现）的变化。椎体数的变化，可能影响回避游泳，也将进行分析。将湖泊种群与迁徙种群（假定的祖先种群）进行比较。将进行实地观察和胃内容物分析，以评估在发育过程中以及种群之间在饮食、觅食行为和微生境利用方面的变化。

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.