Innovative airborne DNA approach for monitoring honey bee foraging and health

Environmental DNA (eDNA) refers to genetic material collected from the environment and not directly from an organism. eDNA is best known as a tool in aquatic ecology but has been found associated with almost every substrate examined including soils, surfaces, and riding around on other animals. The collection of eDNA from air is one of the most recent advances and has been used to monitor a variety of organisms, including plants, animals, and microorganisms. Current evidence suggests a high turnover rate providing a recent signal for the presence of DNA associated with an organism. Here, we test whether material carried in air can be collected from honey bee hives to evaluate recent foraging behavior and colony health. We sampled air using purpose-built “bee safe” air filters operating for 5-6 hours at each colony. We successfully recovered plant, fungal and microbial DNA from the air within hives over a 3-week pilot period. From these data we identified the core honey bee microbiome and plant interaction data representing foraging behaviour. We calculated beta diversity to estimate the effects of apiary sites and sampling date on data recovery. We observed that variance in ITS data was influenced by sampling date. Given that honey bees are generalist pollinators our ability to detect temporal signals in associated plant sequence data suggest this method opens new avenues into the ecological analysis of short-term foraging behavior at the colony level. In comparison variance in microbial 16S sequencing data was more influenced by sampling location. As the assessment of colony health needs to be localized, spatial variance in these data indicate this may be an important tool in detecting infection. This pilot study demonstrates that colony air filtration has strong potential for the rapid screening of honey bee health and for the study of bee behaviour.

环境DNA（eDNA）指从环境中而非直接从生物体中采集的遗传物质。eDNA最广为人知的应用是作为水生生态学研究工具，但现已发现其与几乎所有被检测的基质相关，包括土壤、各类表面，以及附着在其他动物体表的基质。从空气中采集eDNA是近年来的最新进展之一，该方法已被用于监测包括植物、动物和微生物在内的多种生物。现有研究证据表明，eDNA具有较高的周转速率，能够提供与生物体相关的DNA存在的近期信号。本研究旨在验证是否可通过采集蜜蜂蜂箱内空气中的物质，以评估蜂群近期的觅食行为与群体健康状况。我们为每个蜂群配备专用的“蜜蜂安全型”空气过滤器进行空气采样，采样时长为5至6小时。在为期3周的预实验阶段中，我们成功从蜂箱内的空气中回收了植物、真菌与微生物的DNA。基于这些数据，我们鉴定出了蜜蜂核心微生物组（microbiome），并获取了代表觅食行为的植物互作数据。我们通过计算β多样性（beta diversity），评估了养蜂场点位与采样日期对数据回收率的影响。结果显示，内转录间隔区（ITS）测序数据的方差受采样日期的影响更为显著。鉴于蜜蜂是泛化传粉者（pollinators），我们能够在关联的植物序列数据中检测到时间信号，这表明该方法为蜂群水平的短期觅食行为生态学分析开辟了新途径。相比之下，微生物16S测序（16S sequencing）数据的方差更多受采样点位的影响。由于蜂群健康评估需要本地化的监测数据，此类数据中的空间方差表明，该方法或可成为检测蜂群感染的重要工具。本预实验证明，蜂箱空气过滤技术在快速筛查蜜蜂健康状况以及研究蜜蜂行为方面具有巨大潜力。