The diversity and consequences of development in marine invertebrates have, for a long time, provided the opportunity to understand different evolutionary solutions to living in variable environments. However, discrete classifications of development can impede a full understanding of adaptation to variable environments when behavioral, morphological, or physiological flexibility and variation exist within traditionally defined modes of development. We report here novel behavioral variability in hatchlings of a marine gastropod, the Florida crown conch (Melongena corona), that has broad significance for understanding the correlated evolution of development, dispersal, and reproductive strategies in variable environments. All hatchlings crawl away from egg capsules after emergence as larval pediveligers. Some subsequently swim for a brief period (seconds to minutes) before crawling again. From detailed observations of 120 individuals over 30 days, we observed 28 (23.3%) hatchlings swimming at least once (8%–50% per maternal brood). The propensity to swim was unrelated to time spent encapsulated or size at hatching and lasted for 22 days. We manipulated hypothesized environmental cues and found that the proportion of hatchlings that swam was highest in the absence of cues related to habitat or juvenile food and lowest when only habitat cues were present. The relative growth rate of hatchlings was highest when habitats contained a putative juvenile food source. About 44% of hatchlings were competent to metamorphose at emergence but did not metamorphose at this time in the lab or the field. The rate of metamorphosis increased with age and depended on the presence of unknown cues in the field. Crawl-away larvae with prolonged swimming ability may be an adaptation to balance the unpredictable risks of exclusively benthic or pelagic development and to allow the option to disperse to higher-quality habitat.

中文翻译：

---

幼体的行为变异改变了冠海螺（Melongena corona）的扩散潜力：为什么幼虫会爬行但有时会游泳？

长期以来，海洋无脊椎动物发展的多样性和后果为了解生活在可变环境中的不同进化解决方案提供了机会。然而，当行为、形态或生理的灵活性和变异存在于传统定义的发展模式中时，离散的发展分类会阻碍对可变环境的适应的充分理解。我们在此报告了一种海洋腹足动物、佛罗里达冠海螺（Melongena corona)，这对于理解可变环境中发育、传播和繁殖策略的相关进化具有广泛的意义。所有幼体在作为幼虫幼虫出现后都会从卵囊中爬出。有些随后会游泳一小段时间（几秒到几分钟），然后再次爬行。在 30 天内对 120 只个体的详细观察中，我们观察到 28 只 (23.3%) 幼龟至少游泳一次（每只母体孵化 8%–50%）。游泳倾向与封装时间或孵化时的大小无关，持续了 22 天。我们操纵了假设的环境线索，发现在没有与栖息地或幼年食物相关的线索时，游泳的幼龟比例最高，而在只有栖息地线索时最低。当栖息地包含假定的幼鱼食物来源时，幼龟的相对增长率最高。大约 44% 的幼龟在出现时有能力变态，但此时在实验室或野外没有变态。变态的速度随着年龄的增长而增加，并且取决于该领域中未知线索的存在。具有长时间游泳能力的爬行幼虫可能是一种适应，以平衡纯底栖或远洋发育的不可预测风险，并允许选择分散到更高质量的栖息地。