Ecological adaptation in the Galápagos sea lion: The role of foraging ontogeny and interspecific competition

幼年动物发育早期的环境条件对其后期的生境选择、觅食行为和定居模式有很大的影响。这种早期影响可能使种群内的生态分离成为可能。我们之前已经证明了加拉帕戈斯群岛西部和中部种群的加拉帕戈斯海狮（GSL; Zalophus wollebaeki）在食物选择、喂养装置形态和基因组成方面的差异。考虑到该物种相对于其小地理范围的高流动性，这种差异是出乎意料的。西部和中部种群之间的差异可能是由于栖息地的差异以及与主要发生在西部的加拉帕戈斯海狗（GFS; Arctocephalus galapagoensis）的竞争造成的。本文建议通过研究幼海狮觅食行为和面积利用的发展以及与海狮的潜在竞争，来确定个体发育过程中环境差异对西部和中部种群生态适应的贡献。这应该表明栖息地的使用如何与觅食的差异相关，以及这些差异是如何在个体发生过程中建立起来的。此外，该研究将确定觅食个体发育对幼鱼生存的作用，以及与同域GFS的竞争是否可以解释生活在生产力较高水域的西部GSL种群数量少于生产力较低的中部地区。因此，该研究将有助于理解个体发生经验和种间竞争对栖息地选择、种群动态和物种形成早期阶段的作用。

Environmental conditions during early development greatly influence later habitat choice, foraging behavior, and settlement patterns of juvenile animals. Such early influences may enable ecological separation within a population. We have previously demonstrated differences in food choice, morphology of the feeding apparatus, and genetic make-up of Galapagos sea lions (GSL; Zalophus wollebaeki) from the western and central populations of the archipelago. Such differences were unexpected given the high mobility of this species relative to its small geographical range. This difference between the western and central population may be caused by habitat differences as well as competition with Galapagos fur seals (GFS; Arctocephalus galapagoensis) that occur predominantly in the west. We here suggest to study the development of foraging behavior and area-use by young sea lions as well as potential competition with fur seals to determine the contribution of environmental differences during ontogeny to ecological adaptation in western and central populations. This should show how habitat use correlates with differences in foraging and how these differences become established during ontogeny. In addition, the study will determine the role of foraging ontogeny for juvenile survival and if competition with the sympatric GFS can explain that the western GSL population that lives in more productive waters is less abundant than that in the less productive central area. The study will thereby contribute to understanding the role of ontogenetic experience and interspecific competition for habitat choice, population dynamics, and the early stages of speciation.