Data from: Responses of insect herbivores and their food plants to wind exposure and the importance of predation risk

1. Wind is an important abiotic factor that influences an array of biological processes, but it is rarely considered in studies on plant-herbivore interactions. 2. Here, we tested whether wind exposure could directly or indirectly affect the performance of two insect herbivores, Plutella xylostella and Pieris brassicae, feeding on Brassica nigra plants. 3. In a greenhouse study using a factorial design, B. nigra plants were exposed to different wind regimes generated by fans before and after caterpillars were introduced on plants in an attempt to separate the effects of direct and indirect wind exposure on herbivores. 4. Wind exposure delayed flowering, decreased plant height and increased leaf concentrations of amino acids and glucosinolates. 5. Plant-mediated effects of wind on herbivores, i.e., effects of exposure of plants to wind prior to herbivore feeding, were generally small. However, development time of both herbivores was extended and adult body mass of P. xylostella was reduced when they were directly exposed to wind. By contrast, wind-exposed adult P. brassicae butterflies were significantly larger, revealing a trade-off between development time and adult size. 6. Based on these results, we conducted a behavioral experiment to study preference by an avian predator, the Great Tit (Parus major) for last instar P. brassicae caterpillars on plants that were exposed to either control (no wind) or wind (fan-exposed) treatments. Tits captured significantly more caterpillars on still than on wind-exposed plants. 7. Our results suggest that P. brassicae caterpillars are able to perceive the abiotic environment and to trade off the costs of extended development time against the benefits of increased size depending on the perceived risk of predation mediated by wind exposure. Such adaptive phenotypic plasticity in insects has not yet been described in response to wind exposure.1. 风是一类重要的非生物因子（abiotic factor），可调控诸多生物过程，但在植物-植食者互作（plant-herbivore interactions）相关研究中却极少被纳入考量。2. 本研究旨在探明风暴露是否会直接或间接影响取食黑芥（Brassica nigra）的两种昆虫植食者——小菜蛾（Plutella xylostella）与大菜粉蝶（Pieris brassicae）的生长表现。3. 本研究采用因子设计（factorial design）开展温室实验，在植食性幼虫接种植株前后均施加风扇产生的不同风况处理，以此区分风暴露对植食者的直接效应与间接效应。4. 风暴露会延缓植株开花进程、降低株高，并提升叶片中氨基酸与硫代葡萄糖苷（glucosinolates）的含量。5. 风通过植物介导的对植食者的效应（即植食者取食前植株先行受风暴露的效应）整体较为微弱。然而当两种植食者直接暴露于风环境时，其发育时长均被延长，且小菜蛾的成虫体重显著降低。与之相反，经风暴露处理的大菜粉蝶成虫体型却显著更大，这反映出其发育时长与成虫体型间存在权衡（trade-off）。6. 基于上述结果，我们开展了一项行为学实验，以探究鸟类捕食者（avian predator）大山雀（Parus major）对取食于对照（无风）或风暴露（风扇处理）植株的大菜粉蝶末龄幼虫（last instar）的取食偏好。实验结果显示，大山雀在无风植株上捕获的幼虫数量显著高于风暴露植株。7. 本研究结果表明，大菜粉蝶幼虫能够感知非生物环境，并可根据风暴露介导的捕食风险感知情况，权衡延长发育时长的代价与增大体型的收益。目前尚未见针对风暴露的此类昆虫适应性表型可塑性（adaptive phenotypic plasticity）的相关报道。