Data from: Phenological synchrony between a butterfly and its host plants: experimental test of effects of spring temperature

1. Climate-driven changes in the relative phenologies of interacting species may potentially alter the outcome of species interactions. 2. Phenotypic plasticity is expected to be important for short-term response to new climate conditions, and differences between species in plasticity are likely to influence their temporal overlap and interaction patterns. As reaction norms of interacting species may be locally adapted, any such climate-induced change in interaction patterns may vary among localities. However, consequences of spatial variation in plastic responses for species interactions are understudied. 3. We experimentally explored how temperature affected synchrony between spring emergence of a butterfly, Anthocharis cardamines, and onset of flowering of five of its host plant species across a latitudinal gradient. We also studied potential effects on synchrony if climate-driven northward expansions would be faster in the butterflies than in host plants. Lastly, to assess how changes in synchrony influence host use we carried out an experiment to examine the importance of the developmental stage of plant reproductive structures for butterfly oviposition preference. 4. In southern locations the butterflies were well-synchronized with the majority of their local host plant species across temperatures, suggesting that thermal plasticity in butterfly development matches oviposition to host plant development and that thermal reaction norms of insects and plants result in similar advancement of spring phenology in response to warming. In the most northern region, however, relative phenology between the butterfly and two of its host plant species changed with increased temperature. We also show that the developmental stage of plants was important for egg-laying, and conclude that temperature-induced changes in synchrony in the northernmost region are likely to lead to shifts in host use in A. cardamines if spring temperatures become warmer. Northern expansion of butterfly populations might possibly have a positive effect on keeping up with host plant phenology with more northern host plant populations. 5. Considering that the majority of insect herbivores exploit multiple plant species differing in their phenological response to spring temperatures, temperature-induced changes in synchrony might lead to shifts in host use and changes in species interactions in many temperate communities.1. 气候驱动的互作物种相对物候（phenology）变化，或可改变物种间互作的结局。 2. 表型可塑性（phenotypic plasticity）被认为对物种短期响应新气候条件至关重要，不同物种间的可塑性差异或会影响它们的时间重叠程度与互作模式。由于互作物种的反应规范（reaction norms）可能存在本地适应，因此这类由气候诱导的互作模式变化可能存在地域差异。然而，有关可塑性响应的空间变异对物种互作所产生的影响，目前尚未得到充分研究。 3. 本研究通过实验探究了温度对纬度梯度（latitudinal gradient）上橙尖粉蝶（Anthocharis cardamines）春季羽化与其5种寄主植物开花始期之间同步性的影响；同时还研究了若气候驱动下蝴蝶的北扩速度快于寄主植物时，可能对同步性产生的潜在影响。此外，为评估同步性变化如何影响寄主选择，本研究开展了一项实验，以检验植物生殖结构发育阶段对蝴蝶产卵偏好（oviposition preference）的重要性。 4. 在南部区域，蝴蝶与多数本地寄主植物在各温度梯度下均保持良好同步性，这表明蝴蝶发育的热可塑性能够匹配寄主植物的发育进程，且昆虫与植物的热反应规范会使二者在气候变暖下的春季物候提前幅度相似。然而在最北部区域，蝴蝶与其中两种寄主植物的相对物候随温度升高发生了改变。本研究还证实，植物发育阶段对产卵行为具有重要影响，并据此得出结论：若春季温度升高，最北部区域由温度诱导的同步性变化，或会导致橙尖粉蝶的寄主使用模式发生转变。蝴蝶种群的北扩，或许有助于它们跟上更北方寄主种群的物候变化。 5. 鉴于多数植食性昆虫（insect herbivores）会利用多种对春季温度响应存在差异的植物物种，由温度诱导的同步性变化，或会在众多温带群落中引发寄主使用模式转变与物种互作改变。