OPUS: The Biotic Challenge Hypothesis, an Eco-evolutionary Mechanism for Tropical Diversity

热带生物惊人的多样性和它们之间的物种相互作用抑制了对这种多样性如何产生和物种如何共存的概括。基于简单群落和生态模型的概括不能充分扩大到包括物种最丰富的陆地组合，特别是那些在新世界热带（新热带）的陆地组合。对新热带以昆虫为食的鸟类及其猎物的巨大多样性特征的回顾启发了生物挑战假说，该假说认为，由于热带栖息地在数千万年的时间里积累了各种各样的物种，激烈的竞争和捕食使许多独特和专门的适应进化成为必要。这一过程是如何增加新特征和新物种的进化，以及热带系统的脆弱性的，目前还没有得到充分的阐述。该项目假设物种之间的相互作用，特别是对资源的捕食和竞争，对于理解高度多样化热带群落的进化和当前的威胁至关重要。这个项目的一个关键的更广泛的影响将是探索为什么热带物种对全球变化威胁如此敏感，因此需要更有效的保护和管理策略。其他更广泛的影响包括建立和传播一个公开可用的数据库，培训具有不同背景的学生，以及为各种受众制作材料。生物挑战假说整合了两种进化物种的相互作用，捕食者和猎物之间的共同进化军备竞赛，以及涉及数十种通常在系统发育上不相关的物种的扩散竞争。这些相互作用使得觅食专业化成为必要，以寻找、制服和处理猎物；和能量保守的生理。这些特化的代价是较差的扩散能力，增加了物种内部的地理分化和物种形成率，后者积极加强了热带物种多样性。该项目将详细探讨捕食者、猎物和竞争者之间的动态相互作用如何推动许多动植物组合的多样化，包括鸟类和它们的昆虫猎物，热带植物和它们的敌人，以及植物-动物互惠关系。最重要的更广泛的影响是这本书详细阐述了生物挑战假说的原因和后果，特别是因为它与生态专业化和不良分散的进化有关。这两种结果都加剧了热带物种对许多全球变化影响的敏感性，包括昆虫数量下降。其他更广泛的影响包括训练一名本科生和一名早期研究生建立一个鸟类猎物数据数据库，书中的许多推论都是基于这个数据库；并向广大受众传播研究结果和概念。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。

The staggering diversity of tropical organisms and their species interactions have inhibited generalizations about how this diversity arose and how species coexist. Generalizations based on simple communities and ecological models fail to scale-up adequately to encompass the most species-rich terrestrial assemblages, especially those in the New World tropics (Neotropics). Review of the vast diversity of traits among neotropical insect-feeding birds and their prey inspired the Biotic Challenge Hypothesis, which asserts that as tropical habitats accumulated diverse species over tens of millions of years, intense competition and predation necessitated the evolution of many unique and specialized adaptations. How this process might have increased the evolution of new traits and species, and also the fragility of tropical systems, is inadequately articulated. This project posits that interactions among species, especially predation and competition for resources are essential to understanding the evolution of hyper-diverse tropical communities and current threats. A key broader impact of this project will be to explore why tropical species are so sensitive to global change threats and thus require more effective conservation and management strategies. Other broader impacts include the creation and dissemination of a publicly available database, training students with diverse backgrounds, and production of materials for a range of audiences. The Biotic Challenge Hypothesis integrates two evolutionary species interactions, coevolutionary arms races between predators and their prey, and diffuse competition involving dozens of often phylogenetically unrelated species. These interactions necessitated feeding specializations to find, subdue, and process prey; and energetically conservative physiologies. A tradeoff (cost) of these specializations is poor dispersal ability, augmenting both geographic differentiation within species and speciation rate, the latter positively reinforcing tropical species diversity. This project will explore in detail how the dynamic interactions among predators, prey, and competitors has driven diversification in many animal and plant assemblages, including birds and their insect prey, tropical plants and their enemies, and plant-animal mutualisms. The most important broader impact is a book that elaborates the causes and consequences of the Biotic Challenge Hypothesis, especially as it relates to the evolution of ecological specialization and poor dispersal. Both of these outcomes exacerbate the sensitivity of tropical species to many global change impacts including declining insect populations. Other broader impacts include training an undergraduate and an early graduate student to produce a database of avian prey data, on which many inferences in the book are based; and disseminating the findings and concepts to broad audiences.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.