Plant herbivore defense syndromes mediated by canopy structural complexity

植物在许多方面保护自己不受食草性昆虫的攻击。例如，它们制造化学毒药，并建造机械防御系统，就像荆棘一样。植物也利用食草动物的捕食者作为保护，遵循一句古老的谚语，即我敌人的敌人就是我的朋友。但没有一家工厂能够负担得起在所有类型的国防上进行投资。对一种战略的投资必须与对另一种战略的投资进行权衡，导致植物物种在它们所采用的防御组合中存在巨大差异。事实证明，理解决定植物物种防御策略的环境因素是困难的。然而，应对这一挑战对于理解植物为什么是这样的很重要。反过来，这对指导农业中的植物育种和病虫害管理实践也很重要。这项研究将测试一种新的想法，即植物如何使鸟类更容易捕食草食昆虫。具体地说，据预测，鸟类将被树枝较少的植物所吸引，在这些植物上，它们最容易移动和寻找昆虫。由于鸟类清除了大量的昆虫天敌，这些植物应该需要较少的化学和机械防御投资。因此，这项研究将揭示植物的分枝模式是否为植物如何防御自己的可预测变异模式奠定了基础。研究人员将与当地教师合作，利用该项目的成果，促进本科生和K-12学生对研究实践的理解。半个多世纪以来，植物防御食草动物的进化生态学一直是一个重要的研究课题。食草动物防御的类型和规模都因地理、植物科和种之间、种群和物种内的个体之间、甚至个体内组织之间的不同而有很大差异。权衡被认为是这种变异的核心，但在多变的生态环境和进化历史施加的限制的复杂环境中，预测权衡如何发挥作用一直是困难的。这项研究测试了一个新的假设，即植物结构的复杂性驱动了植物多变量食草动物防御策略的变异。这些预测将通过表征加州海岸鼠尾草生态系统30种共生植物(灌木、大型多年生草本植物)的结构复杂性、鸟类间接防御、节肢动物间接防御和直接防御特征之间的协变性来检验。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。

Plants defend themselves against attack by herbivorous (plant-eating) insects in many ways. For example, they make chemical poisons and construct mechanical defenses, like thorns. Plants also use predators of herbivores for protection, following the age-old adage that the enemy of my enemy is my friend. But no plant can afford to invest in all types of defense. Investment in one strategy must trade-off against investment in another, leading to tremendous variation among plant species in the combination of defenses they employ. Understanding the environmental factors that dictate a plant species' defense strategy has proven difficult. Yet, tackling this challenge is important for understanding why plants are made the way they are. That, in turn, is important for guiding plant breeding and pest management practices in agriculture. This study will test a new idea about how plants can make it easier for birds to pick off herbivorous insects. Specifically, it is predicted that birds will be attracted to plants with few branches, where they can most easily move and find insects. Because birds remove lots of insect enemies, those plants should need to invest less in chemical and mechanical defenses. Thus, this study will thus reveal whether a plant's branching pattern sets the stage for predictable patterns of variation in how plants defend themselves. The researchers will work with local teachers to use results from the project to promote an understanding of research practices to undergraduate and K-12 students. The evolutionary ecology of plant defense against herbivores has been a major program of research for more than half a century. Both the types and magnitude of herbivore defenses vary dramatically with geography, among plant families and species, among populations and individuals within species, and even among tissues within individuals. Trade-offs are believed to lie at the core of this variation, but predicting how trade-offs play out has been difficult within the complex milieu of changeable ecological settings and the constraints imposed by evolutionary history. This study tests a novel the hypothesis that plant structural complexity drives variation in multivariate herbivore defense strategy in plants. These predictions will be tested by characterizing co-variation among structural complexity, bird indirect defense, arthropod indirect defense, and direct defense traits for 30 species of sympatric plants (shrubs, large perennial herbs) from the California Coastal Sage Scrub ecosystem.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.