Varroa destructor is an ectoparasitic mite of immature and adult honey bees that can transmit several single-stranded RNA viruses to its host. Varroa reproduce in brood cells, and mite populations increase as colonies produce brood in spring and summer. Mite numbers also can sharply rise, particularly in the fall, by the migration of varroa into hives on foragers. Colonies with high levels of varroa and viruses often die over the winter. Feeding colonies pollen might keep virus levels low and improve survival because of the positive effects of pollen on immunity and colony growth. We compared varroa and virus levels and overwinter survival in colonies with (fed) and without (unfed) supplemental pollen. We also measured the frequency of capturing foragers with mites (FWM) at colony entrances to determine its relationship to varroa and virus levels. Colonies fed supplemental pollen were larger than unfed colonies and survived longer. Varroa populations and levels of Deformed wing virus (DWV) rose throughout the season, and were similar between fed and unfed colonies. The growth of varroa populations was correlated with FWM in fed and unfed colonies, and significantly affected DWV levels. Increasing frequencies of FWM and the effects on varroa populations might reduce the positive influence of supplemental pollen on immune function. However, pollen feeding can stimulate colony growth and this can improve colony survival.

瓦螨是一种未成熟和成年蜜蜂的体外寄生螨，可以将多种单链 RNA 病毒传播给宿主。瓦螨在巢室中繁殖，螨虫数量随着春季和夏季巢穴的繁殖而增加。由于瓦螨迁移到觅食者的蜂巢中，螨虫的数量也会急剧增加，尤其是在秋季。瓦螨和病毒含量较高的蜂群通常会在冬季死亡。由于花粉对免疫力和菌落生长具有积极影响，喂养菌落花粉可能会保持较低的病毒水平并提高存活率。我们比较了有（喂食）和没有（未喂食）补充花粉的蜂群的瓦螨和病毒水平以及越冬存活率。我们还测量了在蜂群入口处用螨虫 (FWM) 捕获觅食者的频率，以确定其与瓦螨和病毒水平的关系。喂食补充花粉的菌落比未喂食的菌落更大并且存活时间更长。瓦螨数量和变形翅病毒 (DWV) 水平在整个季节都在上升，并且在喂食和未喂食的群体之间相似。瓦螨种群的增长与喂食和未喂食群体中的 FWM 相关，并显着影响 DWV 水平。FWM 频率的增加及其对瓦螨种群的影响可能会减少补充花粉对免疫功能的积极影响。然而，花粉喂养可以刺激菌落生长，从而提高菌落存活率。