Behavioral Ecology of Monkey Spatial Movements

非技术摘要：Janson，C.提案IBN-9511642：猴子空间运动的行为生态学这个项目的目标是了解动物在已知的家园范围内决定移动到哪里的规则。来自动物觅食研究的大量证据表明，相对于觅食成本，它们试图最大限度地增加食物摄入量。当成本与已知资源之间的移动距离成正比时，该问题本质上类似于人类的“旅行商问题”，即目标是在N个已知城市之间以尽可能短的距离旅行。尽管做出了很大的努力，这个问题仍然抵制精确的数学解决方案，因此动物可能使用的可能规则远不是显而易见的--即使是经济学文献中提供的这个问题的近似解决方案，通常也需要在强大的计算机上进行大量计算。动物是使用简单的规则还是复杂的规则，它们是否“向前看”而不仅仅是下一个眼前的目标，它们的规则与当今计算机上可用的最佳可能解决方案有多接近？一群野生的食果灵长类动物(卷尾猴)被选为研究动物，因为它们每天都需要解决这样的空间问题。它们的主要资源果树是稀缺的，而且固定在太空中，而与在平地上移动或飞行相比，在热带雨林的果区之间旅行的成本非常高。圈养中的一些数据表明，吃水果的灵长类动物可以学习和记住大量隐藏食物来源的位置，因此它们可以利用这种能力来解决野外的空间觅食问题。此外，灵长类种群可以被连续跟踪很长一段时间(几周)，从而允许自然空间运动的大样本大小。然而，由于人类研究人员很少知道灵长类种群可获得的所有食物斑块的一切(如位置、生产力和适口性)，因此以前的观察性研究的结果并不容易解释。为了减少这些解释问题，该项目使用了一种野外实验方法，即在一系列悬挂在树上的木制平台上提供水果(橘子)--调查人员可以完全控制平台上的位置、食物奖励的数量和食物类型。在这个阿根廷亚热带研究地点，只有在几乎所有天然水果生产都停止的冬季工作，才能最大限度地减少其他天然食物来源的混杂影响。(使用计算机程序)选择平台的空间位置，使得从一个平台到下一个平台的移动选择的顺序将根据所使用的可能的决策规则而不同。测试的具体规则包括(1)对延迟奖励和即时奖励的重视程度不同，(2)权衡距离和食物数量，以及(3)按平台单独检查奖励或在整个平台空间阵列上整合。研究卷尾猴在已知资源之间移动的规则将有助于我们理解(1)觅食行为中一个被很大程度上忽视的方面，(2)灵长类动物以及可能的人类对空间知识的可能心理组织，以及(3)动物物种资源基础的哪些方面可能有利于复杂心理图谱的进化，这与人类祖先的智力进化有关。关于这些猴子的空间决定的知识也将提供关于它们的空间需求以及它们如何对栖息地干扰做出反应的重要信息，随着越来越多的猴子被用于实验室，这一结果可能有助于在野外保护这种物种。

Non-technical Summary: Janson, C. Proposal IBN-9511642: 'Behavioral Ecology of Monkey Spatial Movements' The goal of this project is to understand the rules animals use to decide where to move within a known home range. Much evidence from studies of animal foraging suggests that they attempt to maximize food intake relative to foraging costs. When costs are proportional to distance moved between known resources, the problem is essentially similar to the human 'Traveling Salesman Problem' , in which the goal is to travel among N known cities in the shortest possible distance. This problem has resisted precise mathematical solution despite great efforts, and thus the possible rules that animals might use are far from obvious -- even the approximate solutions to this problem offered in the economics literature typically involve vast numbers of calculations on powerful computers. Do animals use simple or complex rules, do they 'look ahead' to more than the next immediate goal, how closely do their rules approach the best possible solutions available on computers today? A wild population of fruit-eating primates (capuchin monkeys) were chosen as the study animals because they need to solve such spatial problems every day. Their major resources, fruit trees, are scarce and fixed in space, while the cost of traveling between fruit patches in rainforests is very high compared to moving on level ground or flying. Some data in captivity suggest that fruit-eating primates can learn and remember the locations of large numbers of hidden food sources, so it is plausible that they can use such abilities to solve spatial foraging problems in the wild. In addition, primate groups can be followed continuously for long periods (weeks), thus allowing for large sample sizes of natural spatial movements. However, because human researchers can rarely know everything (such as location, productivity, and palatability) about all the food patches available to a primate group, the results of previous observational studies are not easy to interpret. To reduce these problems of interpretation, this project uses a field-experimental approach in which fruit (tangerines) is provided on a series of wooden platforms suspended from trees -- the investigator can completely control the location, amount of food reward, and food type on the platforms. Confounding influences of other, natural food sources are minimized in this subtropical Argentine study site by working only in winter, when nearly all natural fruit production stops. The spatial locations of the platforms are chosen (using a computer program) so that the sequences of movement choices from one platform to the next will differ depending on the possible decision rules used. The specific rules tested will include ones that (1) place differing amounts of emphasis on delayed vs. immediate rewards, (2) trade off distance vs. amount of food, and (3) examine rewards individually by platform or integrate over the entire spatial array of platforms. Investigating the rules capuchins use to move between known resources will help us to understand (1) a largely neglected aspect of foraging behavior, (2) the likely mental organization of spatial knowledge in primates and possibly humans, and (3) what aspects of the resource base of an animal species may favor the evolution of complex mental maps, which have been implicated in the evolution of intelligence in man's ancestors. The knowledge about spatial decisions of these monkeys will also provide important information about their spatial needs and how they may react to habitat disturbance, results which may help in conserving this species in the wild as increasing numbers are taken for laboratory use.