Collaborative Research: Division of Labor in Communal Groups

项目摘要：从昆虫到人类的社会群体将他们的劳动在个体之间进行分工，以便不同的群体成员专门从事不同的任务。长期以来，这种劳动分工一直被认为是社会适应的关键之一。最近的研究表明，其潜在机制涉及个人行为的简单规则，当与个人之间的相互作用相结合时，会产生复杂的群体水平属性（自组织）。自组织被认为发生在所有生物水平上，但这已被证明很难通过实验来验证。社会群体为检验这一论断提供了一个重要的机会，因为个体可以被观察，群体成员之间的互动也可以被量化。本研究将探讨简单社会群体成员之间的局部互动如何在早期社会进化中产生劳动分工。核心假设是，如果群体成员之间的互动放大了他们执行任务的概率差异，那么劳动分工就可以自我组织。如果是这样，劳动分工甚至可以在没有选择的情况下出现，因此可以在社会起源时自发出现。另一种假设将得到检验，即劳动分工主要是在社会群体形成后，通过对任务表现差异增加的选择而产生的。这项研究将使用两种不同的建模方法来探索群体成员之间的互动如何可能产生劳动分工。第一种假设是，任何群体中的个体在执行任务的倾向上自然存在差异，这些差异的扩大产生了劳动分工。第二种是从经济学中借鉴的，将群体成员视为竞争任务的“公司”；任务在团队成员之间的分配不是基于最初的差异，而是基于个人执行任务成功程度的差异。为了检验这些模型，并研究劳动分工在早期社会进化过程中是如何变化的，研究人员将比较由正常社会个体组成的群体与被迫形成社会群体的孤独个体的行为。已经确定了两个分类群，可以比较它们的独居种群和群居种群。这些是地面筑巢蜂属Lasioglossum，其中包括独居和群居的物种，以及种子收获蚁种Pogonomyrmex californicus，它有两个相同物种的种群，分别是单独筑巢和群居筑巢。这两种分类群都可以带入实验室，从而可以构建和观察人工社会群体。这提供了一个独特的机会来测试社会结构和劳动分工在从孤独生活到社会生活的转变过程中是如何变化的。更广泛的影响：这项工作对我们理解劳动分工的基本机制做出了重要贡献，劳动分工是人类文化和生物系统中社会组织的重要组成部分。它还解决了跨生物复杂性水平的特性如何出现的广泛问题。该研究从数据收集到分析、展示和发表，积极地吸引本科生和研究生参与科学过程。学生将有机会参与研究的理论和实验部分。这些pi在指导本科生方面有着卓越的记录，包括指导各自机构的本科生研究项目。

Collaborative Proposals 0446415 and 0446342Title: Division of labor in communal groupsJennifer Fewell, Susan Bertram, Penny KukukProject Summary: Social groups from insects to humans divide their labor among individuals so that different group members specialize on different tasks. This division of labor has long been considered one of the key adaptations of sociality. Recent work suggests that its underlying mechanisms involve simple rules of individual behavior, which when combined with interactions among individuals generate complex group level properties (self-organization). Self-organization is thought to occur across all biological levels, but this has proven difficult to test experimentally. Social groups provide an important opportunity to test this assertion, because individuals can be observed and interactions between group members quantified. This research will examine how local interactions among the members of simple social groups could produce division of labor during early social evolution. The central hypothesis is that division of labor can self-organize if interactions among group members amplify differences in their probability of performing tasks. If so, division of labor could emerge even in the absence of selection, and thus could appear spontaneously at the origins of sociality. The alternate hypothesis will be tested, that division of labor is produced primarily via selection for increased differences in task performance after the formation of social groups.The research will use two different modeling approaches to explore how interactions among group members could potentially generate division of labor. The first assumes that individuals within any group vary naturally in their tendency to perform tasks, and that amplification of these differences generates division of labor. The second borrows from economics by treating group members as "companies" that compete for tasks; tasks become distributed among group members based not on initial variation, but on differences in individual success at performing them. To test these models and to examine how division of labor changes during early social evolution, the researchers will compare the behavior of groups made up of normally social individuals to those of solitary individuals that are forced to form social groups. Two taxa have been identified in which solitary and social populations can be compared. These are the ground nesting bee genus Lasioglossum, which contains both solitary and communal species, and the seed harvester ant species, Pogonomyrmex californicus, which has two populations of the same species that initiate nests alone versus in communal groups. Both of these taxa can be brought into the laboratory, allowing artificial social groups to be constructed and observed. This provides a unique opportunity to test how social structure and division of labor change during the transition from solitary to social living. Broader Impact: This work makes an important contribution to our understanding of the mechanisms underlying division of labor, an essential component of social organization within human cultural as well as biological systems. It also addresses the broad question of how properties emerge across levels of biocomplexity. The research actively engages undergraduate and graduate students in the process of science, from data collection to analysis, presentation, and publication. Students will have the opportunity to participate in both the theoretical and experimental components of the research. The PIs have exceptional records of undergraduate mentoring, including directing undergraduate research programs at their respective institutions.