Reduced density and visually complex apiaries reduce parasite load and promote honey production and overwintering survival in honey bees

1. Managed honey bee (Apis mellifera) colonies are kept at much greater densities than naturally occurring feral or wild colonies, which may have detrimental effects on colony health and survival, disease spread, and drifting behavior (bee movement between natal and non-natal colonies).

2. We assessed the effects of a straightforward apiary management intervention (altering the density and visual appearance of colonies) on colony health. Specifically, we established three “high density / high drift” (“HD”) and three “low density / low drift” (“LD”) apiary configurations, each consisting of eight bee colonies. Hives in the HD apiary configuration were of the same color and placed 1m apart in a single linear array, while hives in the LD apiary configuration were placed 10m apart at different heights, facing outwards in a circle, and made visually distinctive with colors and symbols to reduce accidental drift between colonies. We investigated disease transmission and dynamics between the apiary configurations by clearing all colonies of the parasitic mite Varroa destructor, and subsequently inoculating two randomly-chosen colonies per apiary with controlled mite doses.

3. We monitored the colonies for two years and found that the LD apiary configuration had significantly greater honey production and reduced overwinter mortality. Inoculation and intervention status interacted to affect brood mite levels, with the highest levels in the inoculated colonies in the HD configuration. Finally, foragers were more than three times more likely to drift in the HD apiary configurations.

4. Synthesis and applications. Our results suggest that a relatively straightforward management change – placing colonies in low-density visually complex circles rather than high-density visually similar linear arrays – can provide meaningful benefits to the health and productivity of managed honey bee colonies.

1. 人工饲养的西方蜜蜂（Apis mellifera）蜂群的饲养密度远高于自然状态下的野生蜂群，这可能对蜂群健康与存活、疾病传播以及迷巢行为（即蜜蜂在原生蜂巢与非原生蜂巢间的移动）产生不利影响。
2. 本研究评估了一项简易的养蜂场管理干预措施（调整蜂群密度与视觉外观）对蜂群健康的影响。具体而言，我们设置了3组"高密度/高迷巢"（HD）和3组"低密度/低迷巢"（LD）养蜂场布局，每组均包含8群蜜蜂。高密度养蜂场的蜂箱外观颜色统一，以单一直线阵列排布，箱间距仅1米；而低密度养蜂场的蜂箱则以10米间距错落布置于不同高度，呈圆形向外摆放，并通过色彩与标识赋予其视觉辨识度，以减少蜂群间的意外迷巢行为。我们通过清除所有蜂群的寄生螨狄斯瓦螨（Varroa destructor），随后为每个养蜂场中随机选取的2群蜂接种定量螨剂，以此探究不同养蜂场布局下的疾病传播与动态变化。
3. 我们对蜂群进行了为期两年的监测，结果显示低密度养蜂场布局的蜂蜜产量显著更高，且越冬死亡率更低。接种处理与干预布局存在交互作用，共同影响封盖子脾的螨害水平，其中高密度布局下的接种蜂群螨害程度最高。最终，高密度养蜂场布局中，外勤蜂的迷巢概率是低密度组的三倍以上。
4. 综合分析与应用启示：本研究结果表明，一项相对简易的管理调整——将蜂群布置为低密度、视觉复杂度较高的圆形布局，而非高密度、视觉同质化的直线阵列——可显著提升人工饲养西方蜜蜂蜂群的健康水平与生产性能。