DISSERTATION RESEARCH: The adaptive significance of shell color variation in the flat periwinkle Littorina obtusata

海蜗牛以其外壳颜色的多样性而闻名。蛋壳颜色预计会影响可见光的吸收，进而影响体温和健康。先前的结果表明，缅因湾贝壳颜色多样性的模式是由热状态的变化驱动的。在缅因湾更热、更暴露的栖息地，浅色外壳的频率增加，而在较冷的地区，深色外壳占主导地位。此外，操纵实验表明，浅色壳的蜗牛在炎热干燥的条件下具有适应性优势。拟议的研究将进一步测试壳颜色与适合度之间的关系，检查在冷胁迫下的生长和死亡率以及野外对热胁迫的行为反应。拟议的研究将提供一个令人信服的例子，说明热状态变化作为自然种群中选择力的重要性。这样的例子很少，特别是在具有重要生态相关性的自然系统中。此外，了解生物如何响应和适应可变的热状态可能会产生具体的预测，哪些种群和物种最容易受到环境变化的影响，并更好地为保护重要生态系统的方法提供信息。监测油藻壳颜色频率的分布可能是一种经济有效、易于处理的方法，可用于跟踪气候变化对生态群落的影响。

The marine snail Littorina obtusata is noted for remarkable diversity in shell color. Shell color is expected to affect absorption of visible light that may in turn impact body temperature and fitness. Previous results suggest that patterns of shell color diversity in the Gulf of Maine are driven by variation in thermal regime. Lighter shell colors increase in frequency in hotter, more exposed habitats in the Gulf of Maine whereas dark colors dominate populations in cooler areas. In addition, manipulative experiments demonstrated that light shell colored snails are at a fitness advantage under hot, dry conditions. The proposed study will further test the relationship between shell color and fitness, examining growth and mortality rates under cold stress and behavioral responses to thermal stress in the field. The proposed study will provide a compelling example of the importance of variation in thermal regime as a selective force in natural populations. Such examples are rare, particularly in natural systems with significant ecological relevance. Further, understanding how organisms respond and adapt to variable thermal regimes may generate concrete predictions as to which populations and species are most vulnerable to environmental change and better inform the methods used to protect important ecosystems. Monitoring the distribution of shell color frequencies in L. obtusata may prove to be a cost-effective, tractable method for tracking the effects of climate change in ecological communities.