The plant stress and plant vigor hypotheses are widely used to explain the distribution and abundance of insect herbivores across their host plants. These hypotheses are the subject of contentious debate within the plant herbivore research community, with several studies finding simultaneous support for both hypotheses for the same plant–herbivore interaction. We address the question of how such support is possible using dynamic site‐occupancy models to quantify the attack dynamics of Cryptorhynchus lapathi (poplar‐willow weevil) on Salix sitchensis (Sitka willow), a dioecious shrub colonizing Mount St. Helens, Washington, USA after the 1980 eruption, in relation to host plant stress, vigor, and sex. We also introduce several scaling criteria as a rigorous test of the plant vigor hypothesis and demonstrate why modeling insect detection is important in plant–insect studies. Weevils responded positively to water stress associated with seasonal dry‐downs, and this response was phenologically compartmentalized by larval feeding mode. Weevils preferentially attacked large and/or flowering stems, imposing an ecological cost on willow reproduction via increased stem mortality and susceptibility to future attack. We propose that the dual response to host plant stress and vigor is due to the synchronization between young weevil larval feeding and willow nutrient pulses that are mediated by environmental stress. In turn, this process drives successional dynamics, causing the juvenilization of upland willow plants and possibly delaying establishment of a willow‐dominated upland sere. These results highlight the common, but often overlooked, phenological basis of the plant stress and plant vigor hypotheses, which both focus on how stress changes the quality of plant resources available to immature insects.

中文翻译：

---

通过重新将植物胁迫和活力假设重新集中在物候学上，研究初生演替过程中草食动物的影响

植物胁迫和植物活力假说被广泛用于解释昆虫草食动物在其宿主植物中的分布和丰富度。这些假说是植物食草动物研究界争论的主题，一些研究发现同一植物-草食动物相互作用同时支持这两个假说。我们解决这种支持是如何可能的使用动态站点占用模型来量化的打击力度问题Cryptorhynchus干象（杨树，柳树象鼻虫）对柳西加（Sitka杨柳）是一种雌雄异异的灌木丛，在1980年喷发后在美国华盛顿的圣海伦斯山定居，与寄主植物的压力，活力和性有关。我们还引入了几种缩放比例标准，作为对植物活力假设的严格检验，并说明了为什么建立昆虫检测模型在植物昆虫研究中很重要。象鼻虫对与季节性干旱有关的水分胁迫有积极的反应，这种反应在幼虫喂养方式上按物候划分。象鼻虫优先侵害大的和/或开花的茎，通过增加茎的死亡率和对未来侵袭的敏​​感性，对柳树繁殖造成生态成本。我们认为，对寄主植物胁迫和活力的双重反应是由于象鼻幼虫幼体摄食和环境胁迫介导的柳树养分脉冲之间的同步。反过来，这一过程推动了演替过程的发展，导致了高地柳树植物的幼化，并可能延迟了以柳树为主的高地柳树的建立。这些结果突出了植物胁迫和植物活力假说的共同但经常被忽视的物候学基础，它们都集中在胁迫如何改变未成熟昆虫可获得的植物资源质量上。