Testing the efficacy of a thermal camera as a search tool for locating wild bumble bee nests

Research into how bumble bee colonies respond to the stressors affecting their populations are currently studied in the laboratory using commercially reared Bombus terrestris colonies. Understanding how these stressors affect wild bumble bee colonies in the field would be a crucial step forward for the conservation of bumble bee species. Currently, visual cues are used to locate bumble bee nests, using human searchers looking for the worker nest traffic, but the limitations of this method mean that low numbers of nests are found and so a new method that looks to tackle these limitations is needed. Thermal cameras have been considered as a potential nest searching tool because they reduce the visual complexity of the environment by displaying a homogenized thermal landscape to the searcher. In this study, we compare the use of a thermal camera to human searches using two trials: (i) using inexperienced volunteers to search along the transect for a known bumble bee nest and (ii) using an experienced individual to search across a number of novel locations. We found thermal cameras are not a better nest detection technique than human searches, having low success rates across both trials. We discuss the limitations of thermal cameras as a technique and propose how the technology could be improved for future studies.目前，针对熊蜂蜂群如何响应影响其种群的各类胁迫因子的研究，多在实验室中利用商业化饲养的地熊蜂（Bombus terrestris）蜂群开展。明确此类胁迫因子对野外野生熊蜂蜂群的影响机制，是推进熊蜂物种保护工作的关键环节。当前，定位熊蜂巢穴的常规方法依靠人类搜索者通过观察工蜂出入的蜂群轨迹来寻找，但该方法存在局限性，仅能发现少量巢穴，因此亟需一种可解决此类问题的新型搜寻方法。热成像相机（thermal camera）被视为潜在的巢穴搜寻工具，因其可向搜索者呈现均质化的热景观，从而降低环境的视觉复杂度。本研究通过两组对照试验，对比了热成像相机与人工搜索的应用效果：(i) 由无经验志愿者沿样带搜寻已知的熊蜂巢穴；(ii) 由经验丰富的人员在多个全新地点开展搜寻。研究结果表明，热成像相机的巢穴探测成功率在两组试验中均较低，并不优于人工搜索方法。本文讨论了热成像相机作为探测技术的局限性，并提出了未来研究中可对该技术进行优化的方向。