Bats provide numerous ecosystem services as they pollinate, disperse seeds, and reduce insect populations. It is thus vital to monitor and understand their foraging habits. We analyzed sterols and stanols in a rare discovery of a ∼4,300‐year‐old bat guano deposit from a Jamaican cave to infer relative changes in bat feeding guilds over four millennia. In this deposit, zoosterols and phytosterols, in conjunction with δ¹³C and C/N data, revealed two periods of increased frugivory relative to insectivory from ca. 1000‐500 BCE and ca. 700–1900 CE. We propose two possible explanations for these intervals of increased frugivory relative to insectivory. (1) Previous paleoclimate data suggested these intervals were warmer and drier in the region, which we hypothesize resulted in reduced insect availability. We supported these inferences by comparing the same analytes in fresh guano from frugivorous, insectivorous, and sanguinivorous (blood‐drinking) bats, which showed that bats with animal‐based diets produced guano with lower C/N ratios and higher cholesterol/(cholesterol + sitosterol) ratios than those with fruit‐based diets. (2) The change in the chemical composition of the bat guano during these two periods may also be the result of a shift in the relative species composition of the bat roost that is a greater proportion of frugivorous relative to insectivorous bats during these two periods. This novel, non‐invasive method, based on the chemical composition of bat guano, tracked changes in tropical bat foraging habits extending back in time over four millennia.

中文翻译：

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由热带鸟粪矿床确定的蝙蝠栖息地饮食变化的4,300年历史

蝙蝠在授粉，分散种子和减少昆虫种群的过程中提供多种生态系统服务。因此，至关重要的是监视和了解其觅食习惯。我们从一个牙买加洞穴中发现了一个约4,300年的蝙蝠鸟粪沉积物，以推断四千年来蝙蝠喂养行会的相对变化，我们分析了甾醇和甾烷醇。在该存款，动物固醇和植物甾醇中，结合δ ¹³C和C / N数据显示，相对于约食虫的食虫性，食肉期增加了两个时期。公元前1000-500年，大约 公元700–1900年。对于节食相对于食虫增加的间隔，我们提出了两种可能的解释。（1）以前的古气候数据表明，该区域的这些间隔较暖和较干燥，我们假设这导致昆虫的可利用性降低。我们通过比较食食性，食虫性和食血性（血液饮用）蝙蝠的新鲜鸟粪中的相同分析物来支持这些推论，结果表明，以动物为基础的饮食的蝙蝠生产的鸟粪中的C / N比较低，而胆固醇/胆固醇/（胆固醇+谷固醇）比基于水果饮食的比例高。（2）在这两个时期中，蝙蝠鸟粪的化学成分的变化也可能是蝙蝠栖息地的相对物种组成发生变化的结果，在这两个时期中，食性蝙蝠相对于食虫性蝙蝠的比例更大。这种基于蝙蝠鸟粪的化学成分的新颖，非侵入性的方法追踪了热带蝙蝠觅食习性的变化，这种变化可以追溯到四千年前。