Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.
Acoustic and Functional Ecology, Max Planck Institute for Biological Intelligence, Seewiesen, Germany.
Elife. 2023 Apr 18;12:e84190. doi: 10.7554/eLife.84190.
Predators that target multiple prey types are predicted to switch foraging modes according to prey profitability to increase energy returns in dynamic environments. Here, we use bat-borne tags and DNA metabarcoding of feces to test the hypothesis that greater mouse-eared bats make immediate foraging decisions based on prey profitability and changes in the environment. We show that these bats use two foraging strategies with similar average nightly captures of 25 small, aerial insects and 29 large, ground-dwelling insects per bat, but with much higher capture success in the air (76%) vs ground (30%). However, owing to the 3-20 times larger ground prey, 85% of the nightly food acquisition comes from ground prey despite the 2.5 times higher failure rates. We find that most bats use the same foraging strategy on a given night suggesting that bats adapt their hunting behavior to weather and ground conditions. We conclude that these bats use high risk-high gain gleaning of ground prey as a primary foraging tactic, but switch to aerial hunting when environmental changes reduce the profitability of ground prey, showing that prey switching matched to environmental dynamics plays a key role in covering the energy intake even in specialized predators.
捕食者通常会根据猎物的盈利性来切换觅食模式，以在动态环境中增加能量回报。本研究利用蝙蝠携带的标签和粪便 DNA 宏条形码技术，测试了以下假说：即食虫蝙蝠会根据猎物的盈利性和环境变化做出即时觅食决策。研究表明，这些蝙蝠使用两种觅食策略，平均每晚捕获 25 只小型空中昆虫和 29 只大型地面昆虫，每只蝙蝠的捕获成功率相似，分别为 76%和 30%。然而，由于地面猎物的体型要大 3-20 倍，尽管地面猎物的失败率要高 2.5 倍，但蝙蝠每晚仍有 85%的食物来自地面猎物。研究发现，大多数蝙蝠在给定的夜晚使用相同的觅食策略，这表明蝙蝠会根据天气和地面条件来调整其狩猎行为。研究得出的结论是，这些蝙蝠将地面猎物的高风险高收益觅食作为主要的觅食策略，但当环境变化降低地面猎物的盈利性时，它们会切换到空中觅食，这表明猎物的切换与环境动态相匹配，在专门的捕食者中发挥了重要作用，即使在专门的捕食者中也能满足能量摄入的需求。
