Fitness consequences of individual variation in spatial learning ability in wild food-caching animals

物种内部和物种之间在认知能力和大脑形态方面存在很大差异，但目前尚不清楚为什么存在这种差异。这种差异可能是由于与个体认知能力差异相关的不同生物适应性造成的，但缺乏这一假设的经验证据。不同的任务需要不同的认知能力（例如空间记忆与颜色记忆），然而自然选择是否可以独立塑造不同的认知能力也存在争议。本研究将通过(1)比较野生山山雀在两种环境下的两种认知能力（空间学习和非空间学习）的个体差异来解决这两个主要问题，这两种环境对其中一种能力（空间记忆）提出了不同的要求，空间记忆涉及到数千个先前制造的食物储存；(2)测量与两种认知能力个体差异相关的生物适应性。如果自然选择可以独立地影响这些能力，那么只有空间学习能力的差异应该与不同的生物适合度有关。除了解决关于种群/物种认知能力差异的主要进化问题外，该研究还将对学习和记忆研究产生重大影响。人们仍然普遍认为，联想学习的基本机制对于所有类型的学习和记忆来说都是一样的，因此，研究一种类型的记忆可以为所有类型的记忆提供治疗方法。自然选择可以独立影响不同的认知能力，这表明我们在设计干预措施时必须单独考虑特定的认知能力及其调节机制。拟议的研究还将通过向本科生和研究生提供密集的研究培训，并通过Sagehen生物站向K-12学生和一般公众提供服务，从而提高研究准备和科学素养。

There are large differences in cognitive abilities and brain morphology both within and between species, yet it remains unclear why such differences exist. Such differences may result from differential biological fitness associated with individual variation in cognitive abilities, yet empirical evidence for this hypothesis is lacking. Different tasks require different cognitive abilities (e.g. spatial memory vs. memory for color), yet whether natural selection can shape different cognitive abilities independently is also debated. The proposed research will address these two major questions by (1) comparing individual differences in two cognitive abilities (spatial learning and non-spatial learning in wild food-caching mountain chickadees in two environments that place different demands on just one of these abilities, spatial memory, which is involved in recovering thousands of previously made food caches and (2) measuring biological fitness associated with individual differences in both cognitive abilities. If natural selection can affect these abilities independently, only differences in spatial learning ability should be associated with differential biological fitness. In addition to addressing major evolutionary questions about population/species differences in cognitive abilities, the proposed study will also have significant implications for learning and memory research. It is still generally assumed that the mechanisms underlying associative learning in general are the same for all types of learning and memory and so studying one type of memory allows development of treatments for all memory types. Demonstrating that natural selection can affect different cognitive abilities independently would suggest that we must consider specific cognitive abilities and their regulatory mechanisms individually when designing interventions. The proposed research will also increase research readiness and science literacy by providing intensive research training to undergraduate and graduate students as well as outreach to K-12 students and the general public through the Sagehen Biological Station.