Collaborative Research: Division of Labor in Communal Groups

合作提案0446415和0446342标题：社区群体中的劳动分工詹妮弗·费威尔、苏珊·伯特伦、佩妮·库库克项目摘要：从昆虫到人类的社会群体在个人之间分工，使不同的群体成员专门从事不同的任务。长期以来，这种分工一直被认为是社会性的关键适应之一。最近的研究表明，其潜在的机制包括简单的个人行为规则，当这些规则与个人之间的互动结合起来时，会产生复杂的群体层面的属性(自组织)。自组织被认为发生在所有生物水平，但这已被证明很难在实验中测试。社会团体提供了检验这一论断的重要机会，因为个体可以被观察到，群体成员之间的互动也可以被量化。这项研究将考察简单社会群体成员之间的局部互动如何在早期社会进化过程中产生分工。中心假设是，如果群体成员之间的互动放大了他们执行任务的概率的差异，那么分工可以自组织。如果是这样的话，即使在没有选择的情况下，劳动分工也可能出现，从而在社会性的起源时自发地出现。另一种假设将被检验，即劳动分工主要是通过选择在社会群体形成后任务绩效的差异增加而产生的。该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潜在地产生劳动分工。第一种假设认为，任何群体中的个体在执行任务的倾向上都是自然不同的，这些差异的放大会产生劳动分工。第二种方法借鉴了经济学，将团队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，而是基于个人在执行任务时的成功程度的差异。为了测试这些模型，并研究劳动分工在早期社会进化过程中的变化，研究人员将比较由正常社会个体组成的群体和被迫形成社会群体的孤立个体的行为。已经确定了两个分类群，可以用来比较独居种群和群居种群。这些是地面筑巢蜜蜂属Lasioglossum，它包含独居和公共物种，以及种子收割机蚂蚁物种Pogonomyrmex calforNicus，它有两个相同物种的种群单独筑巢，而不是在公共群体中。这两个分类群都可以被带进实验室，从而可以构建和观察人工的社会群体。这提供了一个独特的机会来检验社会结构和分工在从独居生活向社交生活转变的过程中发生了怎样的变化。更广泛的影响：这项工作对我们理解劳动分工的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。它还解决了一个广泛的问题，即属性是如何跨越生物复杂性水平出现的。这项研究积极地让本科生和研究生参与到科学的过程中，从数据收集到分析、演示和发表。学生将有机会参与研究的理论和实验部分。PI在本科生指导方面有着不同寻常的记录，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.