Mongoose Markets: The Provision and Value of Public Goods

商品和服务的贸易是人类社会的一个基本组成部分，但我们并不是独一无二的：在整个动物世界中，个体在“生物市场”交换合作行为。有很多非人类动物为自己交易商品的例子(例如，为自己梳理毛发)，或者用一种商品交换另一种商品(例如，在与他人打架时，为帮助梳理毛发)。然而，我们对这种市场交易的理解主要在两个方面受到限制。首先，通过关注只有一个人获得好处的情况(比如有人帮朋友买东西)。在现实中，许多合作行为都有多个受益者(比如有人在公园里捡垃圾)。所谓的“公共产品”对其他人有非常不同的影响，因此以非常不同的方式影响团体成员之间的关系。第二个限制是在自然条件下缺乏实验，这对于避免测量圈养生活的奇怪影响以及准确确定一种行为如何影响另一种行为(即因果关系)至关重要。在这个项目中，我们将调查推动生物市场公共产品提供和价值变化的社会因素。要做到这一点，我们将从计算模型中产生新的理论，并使用哨兵行为的跨商品交易(充当抬高的瞭望台)和在可驯服的野生矮小猫鼬种群中进行梳理来测试预测。新的理论是必要的，因为现有的生物市场模型通常侧重于大种群中的排他性伙伴关系，以及与单个接受者的单一商品交易。我们将使用尖端方法对更常见的场景进行建模，在这种场景中，不同的商品(包括公共产品)在小型家庭团体中交换，具有非排他性友谊的团体成员相互重复互动。非洲最小的食肉动物--侏儒猫鼬是检验我们预测的理想动物，原因有几个。团队由5-30个个体组成，他们睡在洞穴里，在共同的领土内觅食和旅行。在一整天中，所有的成年人都充当哨兵--这是一种合作的公共利益行为，因为个体暂停觅食，采取抬高的姿势扫描危险，并向所有组员提供关于危险的有声信息--然后组员在睡觉前在洞穴中相互梳理。梳理毛发对减少寄生在毛皮中的体外寄生虫和维持社会关系都很重要。我们已经研究这些有魅力的生物十多年了，所以我们有大量的数据(来自81个小组年)，关于哨兵的贡献，梳理模式和200多个人的生活。此外，我们已经使研究人群习惯于我们的亲密存在，这使我们能够收集身体质量数据并在自然条件下进行实验(例如，操纵梳理、感知哨兵贡献和捕食风险)。通过使用长期数据和现场实验结果开发和测试新理论，我们将确定：(A)公共产品的提供受到不同商品的接收和提供者之间的竞争的影响，以及(B)公共产品的价值受到其供求的影响。通过这样做，我们将加深对生物市场、群体动力学、合作和社会进化的理解，这些都是广泛的生物学家感兴趣的话题。由于合作和市场交易具有重大的跨学科影响，我们的研究也将补充人类学家、心理学家、经济学家和社会科学家的研究。最后，由于帮助他人是我们在家人、朋友和同事身上欣赏的一种特质，我们将利用一个公共参与活动方案来激励和告知更广泛的受众，让他们了解我们对社会互动的研究，以及通过蓝天研究了解自然世界的重要性。

The trading of goods and services is a fundamental component of human societies, but we are not unique: throughout the animal world, individuals exchange cooperative acts in 'biological markets'. There are lots of examples of non-human animals trading a commodity for itself (e.g., grooming for grooming) or trading one commodity for another (e.g., grooming for help in fights with others). However, our understanding of this market trading has been limited in two main ways. First, by a focus on situations where just one individual receives a benefit (like when someone carries the shopping of a friend). In reality, many cooperative behaviours have multiple beneficiaries (like when someone picks litter in a park). So-called 'public goods' have profoundly different effects on others and so influence relationships between group members in very different ways. The second limitation is a paucity of experiments in natural conditions, which are crucial to avoid measuring odd effects of captive living and to determine exactly how one behaviour influences another (i.e., causality). In this project, we will investigate social factors driving variation in the provision and value of public goods in biological markets. To do so, we will generate new theory from computational modelling and test the predictions using the cross-commodity trading of sentinel behaviour (acting as a raised look-out) and grooming in a tractable wild population of dwarf mongooses.New theory is needed because existing models of biological markets have generally focused on exclusive partnerships in large populations and the trading of single commodities with individual recipients. We will use cutting-edge methods to model the more common scenario where different commodities (including public goods) are exchanged in small family groups where groupmates with non-exclusive friendships repeatedly interact with one another. Dwarf mongooses, Africa's smallest carnivore, are ideal for the testing of our predictions for several reasons. Groups comprise 5-30 individuals who sleep in a burrow, forage and travel together within a shared territory. Throughout the day, all adults act as sentinels - a cooperative act of public good because the individual suspends foraging, adopts a raised position to scan for danger and provides vocal information about danger to all groupmates - and then groupmates groom one another at the burrow before bedtime. Grooming is important both to reduce ectoparasites living in their fur and to maintain social relationships. We have studied these charismatic creatures for over a decade, so have huge amounts of data (from 81 group-years) on sentinel contributions, grooming patterns and the lives of over 200 individuals. Moreover, we have habituated the study population to our close presence, which enables us to collect body-mass data and run experiments (e.g., manipulations of grooming, perceived sentinel contributions and predation risk) in natural conditions.By developing and testing new theory with both long-term data and the results of field experiments, we will determine how (a) the provision of public goods is influenced by receipt of a different commodity and competition among providers, and (b) the value of public goods is affected by their supply and demand. In doing so, we will deepen our understanding of biological markets, group dynamics, cooperation and social evolution, which are topics of interest to a wide range of biologists. Since cooperation and market trading have major interdisciplinary implications, our research will also complement that of anthropologists, psychologists, economists and social scientists. Finally, because helping others is a trait that we admire in family, friends and colleagues, we will use a programme of public engagement activities to enthuse and inform a wider audience about our research on social interactions and the importance of understanding the natural world through blue-skies research.