Department of Fisheries Resources, National Marine Fisheries Research Institute, Kołłątaja 1, 81-332 Gdynia, Poland.
Department of Systematic Zoology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland.
Sci Total Environ. 2024 Dec 1;954:176245. doi: 10.1016/j.scitotenv.2024.176245. Epub 2024 Sep 19.
Winter season is a critical time for honey bees (Apis mellifera) colonies when individual mortalities may lead to total colony losses or diminish productivity in subsequent seasons. A deeper understanding of the causes and consequences of winter mortality is required. In this study, we analyzed winter (November-March) individual bee mortality in an apiary in Central Europe from 1991 to 2023. We observed consistency in mortality times among years, but also some systematic departures from the shared trend. We distinguished four clusters of year-specific mortality trajectories. However, we found no statistically significant differences in means of spring (March-May), autumn (October), winter (November-March) temperatures, or autumn Varroa destructor density among clusters. Nevertheless, our insights into the dynamics of individual bee mortality may be important for determining critical moments during wintering when implementing additional protective measures could prove beneficial. Hypothesis-driven path analysis indicated causal links in our study system, including both direct and indirect influences. The density of V. destructor in autumn was positively related to temperature, especially in the preceding spring, but to a lesser extent also in autumn. Increased winter mortality was related to lower winter temperatures and a higher mite infestation in autumn. We found no significant effects of individual winter mortality on honey harvests in subsequent seasons. Honey harvest was determined by bee abundance in spring, and the latter, unexpectedly, was not related to winter mortality. Our study adds to accumulating evidence of the major role of weather and climatic conditions in the resilience of honey bee colonies and improves our understanding of mortality processes. We highlighted the importance of causative factors, especially seasonal temperatures and V. destructor density, and their potential as predictive indicators of individual winter mortality, bee colony fate, and honey productivity.
冬季是蜜蜂（Apis mellifera）种群的关键时期，个体死亡可能导致整个蜂群损失或降低后续季节的生产力。需要更深入地了解冬季死亡的原因和后果。在这项研究中，我们分析了 1991 年至 2023 年中欧一个养蜂场的冬季（11 月至 3 月）个体蜜蜂死亡率。我们观察到各年死亡率时间的一致性，但也存在一些与共同趋势的系统偏离。我们区分了四个特定年份的死亡率轨迹集群。然而，我们没有发现集群之间春季（3 月至 5 月）、秋季（10 月）、冬季（11 月至 3 月）温度或秋季瓦螨密度的平均值有统计学上的显著差异。尽管如此，我们对个体蜜蜂死亡率动态的深入了解可能对确定冬季实施额外保护措施的关键时刻很重要，因为这可能会带来益处。假设驱动的路径分析表明，我们的研究系统中存在因果关系，包括直接和间接影响。秋季瓦螨的密度与温度呈正相关，尤其是在前一个春季，但在秋季的相关性较小。冬季死亡率增加与冬季温度较低和秋季螨虫感染增加有关。我们没有发现个体冬季死亡率对后续季节蜂蜜产量的显著影响。蜂蜜产量取决于春季蜜蜂的丰度，而出乎意料的是，后者与冬季死亡率无关。我们的研究增加了关于天气和气候条件在蜜蜂种群恢复力中的主要作用的证据，并提高了我们对死亡过程的理解。我们强调了因果因素的重要性，特别是季节性温度和瓦螨密度，以及它们作为个体冬季死亡率、蜜蜂种群命运和蜂蜜生产力的预测指标的潜力。
