Recent studies demonstrated that the Painted Lady (Vanessa cardui), a cosmopolitan diurnal butterfly performs long-range migration between subtropical Africa and north-western Europe, covered by individuals belonging to up to six generations. Here we analyse temporal patterns of complete annual migratory activity of the Painted Lady in Hungary, located in its Central European migratory route, almost completely unstudied before. To do so, we used field occurrence data collected between 2000-2019 and estimated temporal patterns in migratory activity by fitting kernel density functions on the daily mean number of individuals and observation frequency. The temporal distributions of kernel density estimates were analysed as a function of time and key climatic predictors of the study area. We found that (i) the timing of spring arrivals has been advancing; (ii) the relative intensity of the first and last migratory peaks of the Painted Lady significantly increased during the past decades, and (iii) intensity of the last migratory peak is related to the mean temperature of the previous month, inferring that the migration is shifting to earlier dates and their volume of the migration has substantially intensified, evoking mutually non-exclusive, competing hypotheses. Our study indicates the strengthening migration activities of a southerly distributed, long-distance migrant diurnal butterfly, most probably linked to the northward shift of wintering areas induced by warming trends of the southern parts of Europe. However, the complexity of the likely processes leading to changing migratory strategies calls up for further research in both breeding and wintering areas. This article is protected by copyright. All rights reserved.

中文翻译：

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迁徙日间蝴蝶飞行活动的长期时间模式

最近的研究表明，彩绘女士 (Vanessa cardui)，一种世界性的昼夜蝴蝶，在亚热带非洲和西北欧之间进行长距离迁徙，由多达六代的个体覆盖。在这里，我们分析了匈牙利彩绘女士的完整年度迁徙活动的时间模式，位于其中欧迁徙路线上，以前几乎完全没有研究过。为此，我们使用了 2000 年至 2019 年间收集的野外发生数据，并通过在每日平均个体数和观察频率上拟合核密度函数来估计迁徙活动的时间模式。核密度估计的时间分布被分析为研究区域的时间和关键气候预测因子的函数。我们发现（i）春季到来的时间已经提前；(ii) 过去几十年彩绘夫人的第一个和最后一个迁徙高峰的相对强度显着增加，以及 (iii) 最后一个迁徙高峰的强度与上个月的平均温度有关，推断迁徙是向更早日期的转移及其迁移量大大增加，引发了相互非排他性、相互竞争的假设。我们的研究表明，一种向南分布的长距离迁徙日间蝴蝶的迁徙活动加强，这很可能与欧洲南部变暖趋势引起的越冬区向北移动有关。然而，导致迁徙策略改变的可能过程的复杂性要求在繁殖和越冬地区进行进一步研究。本文受版权保护。版权所有。