Collaborative Research: The role of compensation in the evolution of ornaments

进化导致了男性许多奇怪而华丽的身体特征(即饰品)，但它们如何仍然是男性素质的可靠指标仍存在争议。目前的假说表明，装饰品对它们的携带者来说是昂贵的，然而，关于装饰品降低运动能力或降低存活率或生殖成功(即达尔文适合度)的研究一直没有定论。对于大型饰品，选择应该有利于特征和行为的进化，以抵消饰品的成本，从而掩盖它们的真实成本。柄眼苍蝇由于其夸张的头部形态，提供了一个理想的模型系统来测试与雄性装饰相关的成本和权衡，眼睛在长柄的末端移位。这些苍蝇在肌肉和翅膀大小上表现出相当大的差异，这些补偿性特征可能抵消眼柄对飞行性能的惯性影响。这项研究结合了生物力学和飞行性能实验，以表征与装饰物大小有关的补偿能力，并确定装饰物和补偿特性的相互作用如何影响苍蝇逃避捕食者和繁殖的能力。这项拟议的研究有可能极大地修改我们对夸张特征如何演变的理解，还可以提高我们对装饰品生物力学补偿的理解，并为微型无人机等生物启发工程努力提供信息。这项研究将为博士后学者、技术员以及研究生和本科生提供技术培训和专业发展。两个校区的外展工作将为小学生提供STEM教育，并为K-12教育工作者提供培训。本研究采用一种新的理论和实证方法来评估饰品的成本，通过考虑相对饰品大小的补偿能力如何影响生存能力和繁殖力之间的交互作用。为了实现这一目标，将整合三种不同的研究途径。首先，使用Diopsidae科内的柄眼蝇物种，眼柄和补偿性状之间的相关进化模式将揭示选择的宏观进化结果，并检验相对装饰大小将与种内和种间补偿性状的相对大小正相关的假设。其次，一系列飞行性能、机动性和捕食者规避实验将检验相对补偿能力预测生存成本的假设。最后，一系列捕食和竞争相互作用的中游实验将测试对装饰的投资与对补偿特征的投资是否为茎眼苍蝇提供了不同的健康目标；中游实验将评估与补偿不足的大装饰相关的生存成本与与过度补偿小的装饰相关的生存优势的繁殖后果。

Evolution is responsible for many bizarre and showy physical characteristics (i.e. ornaments) in males, but how they remain reliable indicators of male quality remains controversial. Current hypotheses indicate that ornaments are costly to their bearers, however studies testing for decreased locomotor performance or decreased survival or reproductive success (i.e. Darwinian fitness) as a result of ornaments have been inconclusive. For large ornaments, selection should favor evolution of traits and behavior that offset costs of ornaments, thus concealing their true costs. Stalk-eyed flies provide an ideal model system to test for costs and tradeoffs related to male ornamentation due to their exaggerated head morphology, with eyes displaced at the end of long stalks. These flies exhibit considerable variation in muscle and wing size, compensatory traits that may offset the inertial effects of eye stalks on flight performance. This research incorporates biomechanical and flight performance experiments to characterize compensatory ability in relation to ornament size, and determine how the interaction of ornaments and compensatory traits impact flies' ability to evade predators and reproduce. The proposed research has the potential to significantly revise our understanding of how exaggerated traits evolve and also improve our understanding of biomechanical compensation for ornaments and inform bio-inspired engineering efforts such as miniature drones. This research will provide technical training and professional development to a post-doctoral scholar, a technician and graduate and undergraduate students. Outreach efforts at both campuses will provide STEM education to elementary students and training to K-12 educators.This research employs a novel theoretical and empirical approach to assess the costs of ornaments by considering how compensatory ability in relation to relative ornament size affects the interaction between viability and fecundity. Three distinct avenues of research will be integrated to achieve this goal. First, using species of stalk-eye flies within the family Diopsidae, patterns of correlated evolution between eye stalks and compensatory traits will reveal the macroevolutionary consequences of selection and test the hypothesis that relative ornament size will be positively correlated with the relative size of compensatory traits within and across species. Second, a series of flight performance, maneuverability and predator-avoidance experiments will test the hypothesis that relative compensatory ability predicts viability costs. Finally, a series of mesocosm experiments, where predation and competition interact, will test whether investment in ornamentation versus investment in compensatory traits offers different means to the same fitness end in stalk-eyed flies; the mesocosm experiments will assess the reproductive consequences of viability costs associated with under-compensating for large ornamentation compared to the viability advantages associated with over-compensating for small ornamentation.