Data from: Illuminating prey selection in an insectivorous bat community, exposed to artificial light at night

1.Light pollution has been increasing around the globe and threatens to disturb natural rhythms of wildlife species. Artificial light impacts the behaviour of insectivorous bats in numerous ways, including foraging behaviour, which may in turn lead to altered prey selection.

2.In a manipulative field experiment, we collected faecal samples from six species of insectivorous bats in naturally dark and artificially lit conditions, and identified prey items using molecular methods to investigate effects of light pollution on prey selection.

3.Proportional differences of identified prey were not consistent and appeared to be species specific. Red bats, little brown bats, and gray bats exhibited expected increases in moths at lit sites. Beetle-specialist big brown bats had a sizeable increase in beetle consumption around lights, while tri-colored bats and evening bats showed little change in moth consumption between experimental conditions. Dietary overlap was high between experimental conditions within each species, and dietary breadth only changed significantly between experimental conditions in one species, the little brown bat.

4.Policy implications. Our results, building on others, demonstrate that bat-insect interactions may be more nuanced than the common assertion that moth consumption increases around lights. They highlight the need for a greater mechanistic understanding of bat-light interactions to predict which species will be most affected by light pollution. Given differences in bat and insect communities, we advocate biologists, land stewards, and civil planners work collaboratively to determine lighting solutions that minimize changes in foraging behaviour of species in the local bat community. Such efforts may allow stakeholders to more effectively craft management strategies to minimize unnatural shifts in prey selection caused by artificial lights.

1. 全球范围内光污染日益加剧，正威胁着野生动物种群的自然节律。人工光源会通过多种途径影响食虫蝙蝠（insectivorous bats）的行为，包括觅食行为，进而可能改变其猎物选择偏好。
2. 本研究通过控制性野外实验，在自然黑暗与人工光照两种环境下，采集了6种食虫蝙蝠的粪便样本（faecal samples），并利用分子方法（molecular methods）鉴定猎物种类，以此探究光污染对蝙蝠猎物选择的影响。
3. 经鉴定的猎物比例差异并不一致，且呈现出物种特异性。红蝙蝠、小棕蝠以及灰蝙蝠在光照位点的蛾类捕食量均出现了预期的上升。以甲虫为主要猎物的大棕蝠，其周边光照环境下的甲虫捕食量显著增加；而三色蝠与夜蝠在两种实验条件下的蛾类捕食量几乎无变化。各物种在两种实验条件下的饮食重叠（dietary overlap）度均较高，且仅小棕蝠的饮食广度（dietary breadth）在两种实验条件间出现了显著变化。
4. 政策启示：本研究结果与其他同类研究共同表明，蝙蝠与昆虫的互作关系可能比"光照环境下蛾类捕食量增加"这一普遍论断更为复杂。研究强调，需进一步深入理解蝙蝠与光照的互作机制，才能预测哪些物种最易受光污染影响。鉴于蝙蝠与昆虫群落存在差异，我们呼吁生物学家、土地管理者与城市规划者协同合作，制定能够最大限度降低本地蝙蝠群落物种觅食行为改变的照明方案。此类举措可帮助利益相关方更有效地制定管理策略，以减轻人工光源引发的猎物选择非自然偏移。