Doctoral Dissertation Improvement: An Experimental Analysis of Alarm Calling Behavior in Wild Tufted Capuchin Monkeys (Cebus apella)

在美国国家科学基金会的资助下，查尔斯·詹森博士将在阿根廷东北部伊瓜苏国家公园进行为期一年的实地调查，调查卷尾猴报警行为的演变。在许多群居动物中都可以发现，当发现捕食者时，猎物会发出警报。进化生物学家一直对这些叫声感兴趣，因为它们的存在似乎与进化理论相矛盾；在捕食者面前发声的个体比沉默的个体更容易被捕食者发现。人们提出了几种假设，主要分为三大类，来解释警报信号是如何在种群中维持的。首先，警报可能对呼叫者直接有利（例如，如果警报阻止捕食者攻击呼叫者）。其次，警报可能对呼叫者的亲属有利，提醒他们捕食者的存在。最后，在没有捕食者的情况下，个体可能会利用这些叫声来操纵其他群体成员的行为（例如，篡夺食物资源）。虽然这些假设已经在许多鸟类和哺乳动物身上得到了测试，但对灵长类动物的警报呼叫的研究却很少。这项研究的目的是首次广泛测试野生灵长类动物报警叫声进化的多种假设，并检查报警叫声是否被用来从其他群体成员那里篡夺资源。为了检验报警行为的这些方面，将进行三种类型的实验。首先，卷尾猴的捕食者模型（包括豹猫、鹰和蛇）将被用来确定猴子在发现捕食者时的反应。其次，警报呼叫的录音将被回放给鸟类康复中心的活鹰，以确定警报呼叫的产生是否会阻止捕食者攻击呼叫者。第三，悬挂在树枝上的装满香蕉的平台将被用来确定食物的数量和分布是否会影响卷尾猴在没有捕食者时发出警报的倾向。这项研究的智力价值将是更好地理解灵长类动物发出警报的进化和维持的因素。这个项目将得到的数据是重要的，因为进化生物学家对警报的广泛兴趣和灵长类物种的明显缺乏这类数据。这项研究更广泛的影响是，它将增加对灵长类动物行为的一个广泛注意但未被研究的方面的了解。此外，该项目将有助于培养一名灵长类动物行为方面的研究生（共同负责人），以及培养来自东道国的本科生和研究生。阿根廷实地助理将有机会用研究动物进行本科论文研究，共同项目负责人将有机会担任这些项目的论文顾问或联合顾问。最后，在鸟类康复中心进行的实验将为保护工作提供急需的资金，这是上巴拉那大西洋森林唯一剩下的大片连续片段。

With funding from the National Science Foundation, Dr. Charles Janson will conduct one year of fieldwork to investigate the evolution of alarm calling behavior in tufted capuchin monkeys in Iguazu National Park in northeastern Argentina. Alarm calls, vocalizations given by prey species when a predator is detected, are found in many group-living animals. These calls have long been of interest to evolutionary biologists because their existence seems to contradict evolutionary theory; an individual who produces a vocalization while in the presence of a predator is more likely to be detected by the predator than is a silent individual. Several hypotheses, falling into three main categories, have been put forth to explain how alarm calls can be maintained in a population. First, an alarm may benefit the caller directly (e.g., if alarms deter the predator from attacking the caller). Second, an alarm may benefit relatives of the caller by alerting them to the presence of a predator. Finally, individuals may be able to use the calls in the absence of predators to manipulate the behavior of other group members (e.g., to usurp food resources). Although hypotheses falling into these categories have been tested in a number of birds and mammals, studies of alarm calls among primates are scant. The aim of this study is to be the first to extensively test multiple hypotheses for the evolution of alarm calling among wild primates and to examine whether or not alarm calls are used to usurp resources from other group members. In order to examine theses aspects of alarm calling behavior, three types of experiments will be conducted. First, models of predators of capuchin monkeys (including ocelots, hawk-eagles, and snakes) will be used to determine the reaction of the monkeys upon detecting predators. Second, recordings of alarm calls will be played back to live hawk-eagles in an avian rehabilitation center in order to determine if the production of alarm calls deters the predator from attacking a caller. Third, platforms suspended from tree branches and filled with bananas will be used to determine if the amount and distribution of food affects the propensity of capuchin monkeys to produce alarm calls in the absence of a predator. The intellectual merit of this study will be a better understanding of the factors that allowed for the evolution and maintenance of alarm calls among primates. The data which will result from this project are important because of both the widespread interest in alarm calling among evolutionary biologists and the notable absence of such data for primate species. The broader impacts of the study are that it will increase what is known about a widely noted but under-investigated aspect of primate behavior. In addition, this project will contribute to the training of a graduate student (the co-PI) in primate behavior as well as to the training of undergraduate and post-graduate students from the host country. Argentine field assistants will be given the opportunity to conduct research with the study animals for their undergraduate theses and the co-PI will have the opportunity to serve as the thesis advisor or co-advisor for these projects. Finally, the experiments conducted at the avian rehabilitation center will provide much needed funding for conservation efforts in what is the only remaining large continuous fragment of the Upper Parana Atlantic Forest.