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

合作一直是一个长期存在的进化问题，因为合作者在为群体中的其他个人提供利益时会遭受个体健康损失。这个问题的一个值得注意的解决方案涉及绿胡子效应，该效应最初由W·D·汉密尔顿在20世纪60年代初构思，作为一种解释利他主义进化的思想实验，后来由R·道金斯普及。绿胡子效应的主要原理是，存在一个假想的基因或一组关联的基因，它表达一种可感知的特征(例如，绿胡子)，使持有者能够识别其他人的这一特征，并导致持有者根据他们是否具有这种特征而对其他人表现出不同的行为(例如，拥有绿胡子的人帮助其他“绿胡子”个人，而不是没有绿胡子的人)。近年来，在各种生物体中都发现了这些“绿胡子”基因。然而，由于其中大多数是单细胞微生物，如阿米巴、酵母和细菌，我们仍然知之甚少，根据群体成员在其环境中的绿胡子状态，是否以及如何出现复杂、错综复杂的协调和相应的行为。火蚁Solenopsis invicta是少数几种记录了绿胡子效应的群居动物之一。因此，在这个项目中，我们将使用火蚁作为模型系统，研究绿胡子信号与其调节的个人和集体行为之间的关系。一系列的教育和外展计划被提出，包括参与为K-12教师提供教育材料的EcoReach计划，在每年的昆虫节上进行外展，为成年人提供终身学习计划，以及为研究生和本科生提供研究机会，包括来自附近HBCU的一些人。群居的动物一起工作，对它们的群体有利。然而，这种合作行为带来了一个进化问题，因为合作者通常会遭受个体适应度的损失，从而为群体中的其他个体提供好处。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，绿色胡须)，使持有者能够识别其他人的这一特征，并导致持有者根据拥有这一特征的不同而对他人表现出不同的行为，合作就可以进化。该项目的主要目标是研究绿胡子信号与其调节的个体和集体行为之间的关系，以红色输入火蚁Solenopsis invicta作为模型系统。火蚁是为数不多的几种社会动物中的一种，在这种动物中，绿胡子效应已经被记录下来，潜在的绿胡子因素，也就是众所周知的SB超级基因，已经被识别出来。使用这个独特的模型系统，我们的目标是(1)了解不同类别的筑巢伙伴中哪些独特的表皮化学物质构成绿胡子信号，(2)确定工蚁在一对一社交互动中使用此类信号的背景，以及(3)揭示由混合绿胡子基因的工蚁组成的蜂群如何共同决定新出现的蜂群组织。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.