Floral diversity enhances winter survival of honeybee colonies across climatic regions.
Abstract
In temperate climates, winter can be an arduous time for eusocial insects. Survival of honeybee colonies during winter depends on a delicate balance between hive thermoregulation, managing the food reserves and timing the onset of the new worker bee generation. Winter survival is influenced by several factors, most notably colony size, Varroa mite infestation levels and the availability of stored food. Importantly, the climatic conditions and floral resources of the previous foraging season can also impact honeybee health and colony strength before hibernation. This study, conducted across Europe, examines how landscape composition and weather conditions affect the winter survival of honeybee colonies. It uses pollen diversity as a proxy for flower resource quality and available foraging days as a climatic variable to understand their causal relationships to winter survival. We found that landscapes with higher percentages of agricultural areas increased pollen diversity collected by honeybees in autumn, whereas higher percentages of semi-natural areas increased the diversity during summer. Spring and autumn pollen diversity was the main driver for winter survival success, emphasizing the importance of diverse flower resources for colony health. While we did not find a statistically significant effect of weather on winter survival, trends suggest potential influences, warranting further research to confirm and clarify the role of seasonal foraging on colony health.