Collaborative Research: How different forms of competition shape trait evolution and coexistence: A tale of two castes in the turtle ants

地球上生命的多样性，或称“生物多样性”，对于人类赖以生存的自然系统的健康运行至关重要，然而，关于产生生物多样性并在当今系统中维持生物多样性的机制，还有很多东西需要了解。这项研究寻求一个新的水平的综合理解竞争的机械作用，在这个“生产和维护”的生物多样性。竞争是一种普遍存在的物种相互作用，通常表现为对资源的公开争夺。长期以来，它一直与塑造功能分化的物种群体的进化有关，并决定了哪些种类的物种可以在同一个地方生活在一起。然而，关于竞争如何影响生物多样性的生产和维持的综合研究一直难以实现。该项目将整合一系列的比较进化，生态和实验研究，以确定竞争，在其各种形式，形状都精心制作的形态多样性在一组生物和这些物种可以共存于同一栖息地。这项研究为塑造地球生物多样性的关键机制提供了潜在的变革性理解，这对人类福祉至关重要，也日益受到威胁。这项工作的主要科学成果将用于科学艺术合作，为课堂和网上的广大受众提供生物多样性生产和维护的视觉指南。此外，该项目将为来自不同背景的年轻科学家提供广泛的培训和指导，并为实物和数字收藏提供全面的标本贡献。该项目的目标将利用龟蚁（Cecaltes）来实现，龟蚁是一种多样化的新世界谱系，具有蚂蚁之间标志性的表型多样性，在它们所占据的栖息地中具有高度的当地物种丰富性。重要的是，不同的龟蚁特征被称为从事不同形式的竞争：高强度的“有针对性的”竞争与少数专门的竞争对手，与低强度，但普遍的“扩散”多物种组合内的竞争。拟议的工作将整合：1）物种水平的系统发育比较分析的特征，从事对比有针对性的与扩散的竞争; 2）物种共存和性状多样性的分析，对比形式的竞争，在物种丰富的社区;和3）基于现场的实验研究性状介导的竞争强度和结果的严重性，对比不同形式的竞争所定义的场景。正在测试的首要假设是，有针对性的竞争形式驱动更趋多样化的性状多样性和更可预测的性状介导的共存机制。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The diverse array of life on earth, or “biodiversity”, is critical for the healthy functioning of the natural systems that humans depend on. Yet there is much to learn about the mechanisms that produce biodiversity through time and then maintain it in present-day systems. This research seeks a new level of integrative understanding of the mechanistic role of competition in this “production and maintenance” of biodiversity. Competition is a ubiquitous species interaction, often apparent as overt fighting over resources. It has long been implicated in shaping the evolution of functionally differentiated groups of species and in determining which assortment of species can live together in the same place. Yet integrated studies of how competition shapes the production and maintenance of biodiversity have been elusive. This project will integrate a series of comparative evolutionary, ecological, and experimental studies to determine how competition, in its various forms, shapes both elaborate morphological diversity within a group of organisms and which of these species can coexist in the same habitat. This research then offers potentially transformative understanding of key mechanisms shaping earth’s biodiversity, which is both critical for human wellbeing and increasingly threatened. The main scientific findings from this work will be used in a science-art collaboration to bring a visual guide to biodiversity production and maintenance to broad audiences in the classroom and online. Additionally, the project will provide extensive training and mentoring for young scientists from diverse backgrounds and make comprehensive specimen contributions to physical and digital collections.The goals of this project will be addressed using the turtle ants (Cephalotes), a diverse New World lineage with iconic phenotypic diversity among ants and high local species richness in the habitats they occupy. Critically, different turtle ant traits are known to engage with different forms of competition: high intensity “targeted” competition with a small number of specialized competitors, versus low intensity but pervasive “diffuse” competition within multi-species assemblages. The proposed work will integrate: 1) species-level phylogenetic comparative analyses of traits that engage with contrasting targeted versus diffuse competition; 2) analyses of species coexistence and trait diversity for contrasting forms of competition in species-rich communities; and 3) field-based experimental studies of trait-mediated competitive intensity and outcome severity, contrasted across scenarios defined by different forms of competition. The overarching hypothesis being tested is that targeted forms of competition drive both more divergent trait diversity and more predictable trait-mediated mechanisms of coexistence.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.