Collaborative Research: Integrative Approach to Understanding the Emergence of Alternate Social Phenotypes through Greenbeard Effects in the Fire Ant

合作是一个长期存在的进化问题，因为合作者为了给群体中的其他个体提供利益而遭受个体适应度的损失。这个问题的一个值得注意的解决方案是绿胡子效应，它最初是由汉密尔顿在20世纪60年代初提出的，作为一个解释利他主义进化的思想实验，后来被道金斯推广开来。绿胡子效应的主要原则是，存在一个假设的基因，或一组相关的基因，表达一种可感知的特征（例如，绿胡子），使携带者能够识别他人的这种特征，并导致携带者对他人的行为不同，这取决于他们是否拥有这种特征（例如，有绿胡子的个体帮助其他“绿胡子”个体，而不是没有绿胡子的个体）。近年来，这些“绿胡子”基因在不同的生物体中被发现。然而，由于其中大多数是单细胞微生物，如变形虫、酵母和细菌，我们仍然不知道是否以及如何基于群体成员在其环境中的绿胡子状态出现复杂、错综复杂的协调、后果行为。火蚁（Solenopsis invicta）是少数有绿须效应记录的群居动物之一。因此，在这个项目中，我们将以火蚁为模型系统，研究绿须信号与它所调节的个体和集体行为之间的关系。提出了多样化的教育和推广计划，包括参与为K-12教师提供教育材料的EcoReach计划，参加一年一度的昆虫节和成人终身学习计划，以及为研究生和本科生提供研究机会，包括来自附近hbcu的一些学生。群居动物为了群体的利益而合作。然而，这种合作行为带来了一个进化问题，因为合作者通常会为了给群体中的其他个体提供利益而遭受个体适应度的损失。研究人员为这个问题提出了一个潜在的解决方案——如果一个基因表达了一种可感知的特征（例如，绿胡子），那么合作就可以进化，使携带者能够识别他人的这种特征，并导致携带者根据拥有这种特征而对他人采取不同的行为。该项目的主要目的是研究绿须信号与个体和集体行为之间的关系，并以红火蚁（Solenopsis invicta）为模型系统。火蚁是仅有的几种有绿须效应记录的群居动物之一，其潜在的绿须因子，被称为Sb超基因，已经被确定。利用这个独特的模型系统，我们的目标是(1)了解不同种类的巢友中有哪些独特的表皮化学物质构成绿须信号，(2)确定工蜂在一对一的社会互动中使用这种信号的环境，以及(3)揭示由混合绿须基因型的工蜂组成的蜂群如何共同决定新兴的蜂群组织。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Cooperation has been a longstanding evolutionary problem because cooperators suffer an individual fitness loss to provide benefits to other individuals in the group. A notable solution to this problem involves the greenbeard effect, first conceived of by W.D. Hamilton in the early 1960s as a thought experiment to explain the evolution of altruism, and later popularized by R. Dawkins. The main tenet of the greenbeard effect is that there exists a hypothetical gene, or set of linked genes, that expresses a perceptible trait (e.g., green beard), enables the bearer to recognize this trait in others, and causes the bearer to behave differently towards others depending on whether or not they possess this trait (e.g., individuals with green beard help other “green beard” individuals but not ones without green beard). In recent years, these “greenbeard” genes have been discovered in diverse organisms. Yet, because most of these are unicellular microbes, such as amoebae, yeast, and bacteria, we still know little if and how the complex, intricately coordinated, consequential behaviors emerge based on the greenbeard status of group members in their environment. The fire ant, Solenopsis invicta, is one of a few social animals in which a greenbeard effect has been documented. In this project, therefore, we will investigate the relationship between a greenbeard signal and the individual and collective behaviors that it modulates, using the fire ant, as a model system. A diversity of educational and outreach programs is proposed, including participation in the EcoReach program that provides educational materials for K-12 teachers, outreach at the annual Insectival and to a lifelong learning program for adults, as well as research opportunities for graduate students and undergraduates, including some from nearby HBCUs. Social animals work together to the advantage of their group. This cooperative behavior poses an evolutionary problem, however, because cooperators typically suffer an individual fitness loss to provide benefits to other individuals in the group. Researchers have suggested a potential solution for this problem—cooperation can evolve if a gene expresses a perceptible trait (e.g., green beard), enables the bearer to recognize this trait in others, and causes the bearer to behave differently towards others depending on the possession of this trait. The main objective of the proposed project is to investigate the relationship between a greenbeard signal and the individual and collective behaviors that it modulates using the red imported fire ant, Solenopsis invicta, as a model system. The fire ant is one of only a few social animals in which a greenbeard effect has been documented and the underlying greenbeard factor, known as the Sb supergene, has been identified. Using this unique model system, we aim to (1) learn what distinctive cuticular chemicals constitute greenbeard signals in different classes of nestmates, (2) identify contexts in which workers use such signals during one-on-one social interactions, and (3) reveal how colonies composed of workers with a mix of greenbeard genotypes collectively determine the emergent colony organization.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.