Data from: A spatial perspective on the phenological distribution of the spring woodland caterpillar peak

A classic system for studying trophic mismatch focuses on the timing of the spring caterpillar peak in relation to the breeding time and productivity of woodland passerine birds. Most work has been conducted in single-site oak woodlands and little is known about how insights generalise to other woodland types or across space. Here we present the results of a three-year study on the species composition and temporal distribution of the spring caterpillar peak on different tree taxa across 40 woodland sites spanning two degrees of latitude in Scotland. We used molecular barcoding to identify 62 caterpillar species, with winter moth (Operophtera brumata) the most abundant, comprising a third of the sample. Oak (Quercus sp.) and willow (Salix sp.) hosted significantly higher caterpillar abundances than other tree taxa, with winter moth exhibiting similar trends and invariantly proportionate across tree taxa. Caterpillar peak phenology was broadly similar between tree taxa. While latitude had little effect, increasing elevation increased the height of the caterpillar peak and retarded timing by 3.7 days/100m. These findings extend our understanding of how mismatch may play out spatially, with caterpillar peak date varying with elevation, and tree taxa varying in the caterpillar resource that they host.

一项用于研究营养级错配（trophic mismatch）的经典研究体系，聚焦于春季毛虫峰值出现时间与林地鸣禽繁殖期及繁殖生产力的关联。既往多数研究均在单一地点的栎树林地开展，目前对于该研究结论能否推广至其他林地类型或跨空间尺度的适用性仍知之甚少。在此，我们呈现针对苏格兰境内横跨两个纬度跨度的40处林地样地开展的为期三年的研究结果，该研究旨在分析不同树木类群上春季毛虫峰值的物种组成与时间分布特征。研究通过分子条形码技术（molecular barcoding）共鉴定出62种毛虫，其中冬尺蛾（Operophtera brumata）为优势类群，占总样本量的三分之一。栎属（Quercus sp.）与柳属（Salix sp.）上的毛虫种群丰度显著高于其他树木类群，冬尺蛾的种群丰度也呈现出相似的分布趋势，且在各类树木类群中占比恒定。不同树木类群的毛虫峰值物候整体较为相似。纬度对毛虫峰值特征影响微弱，但海拔升高会提升毛虫峰值的种群丰度，并使峰值出现时间延迟3.7天/100米。本研究结果拓展了我们对营养级错配空间分布规律的认知：毛虫峰值日期随海拔变化而改变，不同树木类群所支撑的毛虫资源也存在差异。