Data from: Anthropogenic host plant expansion leads a nettle-feeding butterfly out of the forest: consequences for larval survival and developmental plasticity in adult morphology

Recent anthropogenic eutrophication has meant that hostplants of nettle-feeding insects became quasi-omnipresent in fertile regions of Western Europe. However, hostplant resource quality – in terms of microclimate and nutritional value – may vary considerably between the ‘original’ forest habitat and ‘recent’ agricultural habitat. Here, we compared development in both environmental settings using a split-brood design, so as to explore to what extent larval survival and adult morphology in the nettle-feeding butterfly Aglais urticae are influenced by the anthropogenic environment. Nettles along field margins had higher C/N-ratios and provided warmer microclimates to larvae. Larvae developed 20% faster, and tended to improve their survival rates, on the agricultural land compared to woodland. Our split-brood approach indicated plastic responses within families, but also family effects in the phenotypic responses. Adult males and females had darker wing pigmentation in the drier and warmer agricultural environment, which contrasts with the thermal melanism hypothesis. Developmental plasticity in response to this micro-climatically different and more variable habitat was associated with a broader phenotypic parameter space for the species. Both habitat-expansion and developmental plasticity are likely contributors to the ecological and evolutionary success of these nettle-feeding insects in anthropogenic environments under high nitrogen load.

近年来的人为富营养化使得西欧肥沃区域内，取食荨麻的昆虫的寄主植物几乎随处可见。然而，从微气候与营养价值维度来看，‘原生森林生境’与‘新近农业生境’中的寄主植物资源质量存在显著差异。本研究采用分窝实验设计（split-brood design），对比了两种生境下的昆虫发育情况，以探究人为活动生境对取食荨麻的蛱蝶——荨麻蛱蝶（Aglais urticae）的幼虫存活率与成虫形态特征的影响程度。田埂旁的荨麻碳氮比更高，且能为幼虫提供更温暖的微气候环境。相较于林地生境，农田生境中的幼虫发育速度快20%，且存活率呈现提升趋势。本研究的分窝实验设计结果显示，家系内存在表型可塑性响应，同时表型响应也存在家系效应。在更干燥温暖的农田生境中，雌雄成虫的翅膀色素沉着更深，这一结果与热致黑色素沉着假说（thermal melanism hypothesis）相悖。针对这种微气候差异显著且异质性更强的生境，物种产生的发育可塑性与更宽泛的表型参数空间相关。生境扩张与发育可塑性，二者均可能是这类取食荨麻的昆虫在高氮负荷的人为活动生境中取得生态与进化成功的关键因素。