Ecological theory postulates that niches of co-occurring species must differ along some ecological dimensions in order to allow their stable coexistence. Yet, many biological systems challenge this competitive exclusion principle. Insectivorous bats from the Northern Hemisphere typically form local assemblages of multiple species sharing highly similar functional traits and pertaining to identical feeding guilds. Although their trophic niche can be accessed with unprecedented details using genetic identification of prey, the underlying mechanisms of resource partitioning remain vastly unexplored. Here, we studied the differential diet of three closely-related bat species of the genus Plecotus in sympatry and throughout their entire breeding season using DNA metabarcoding. Even at such a small geographic scale, we identified strong seasonal and spatial variation of their diet composition at both intra- and interspecific levels. Indeed, while the different bats fed on a distinct array of prey during spring, they showed higher trophic niche overlap during summer and fall, when all three species switched their hunting behaviour to feed on few temporarily abundant moths. By recovering 19 ecological traits for over 600 prey species, we further inferred that each bat species used different feeding grounds and hunting techniques, suggesting that niche partitioning was primarily habitat-driven. The two most-closely related bat species exhibited very distinct foraging habitat preferences, while the third, more distantly-related species was more generalist. These results highlight the need of temporally comprehensive samples to fully understand species coexistence, and that valuable information can be derived from the taxonomic identity of prey obtained by metabarcoding approaches.

中文翻译：

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每个人的食物：从 DNA 元条形码推断出的神秘蝙蝠物种的不同摄食习惯

生态理论假设共生物种的生态位必须在某些生态维度上有所不同，以允许它们稳定共存。然而，许多生物系统挑战了这种竞争排斥原则。来自北半球的食虫蝙蝠通常形成多个物种的本地组合，这些物种具有高度相似的功能特征并属于相同的饲养行会。尽管可以使用猎物的遗传鉴定以前所未有的细节访问它们的营养生态位，但资源分配的潜在机制仍然有待探索。在这里，我们研究了Plecotus属的三种密切相关的蝙蝠物种的差异饮食在他们的整个繁殖季节使用 DNA 元条形码。即使在如此小的地理范围内，我们也发现它们的饮食成分在种内和种间水平上存在强烈的季节性和空间变化。事实上，虽然不同的蝙蝠在春季以不同种类的猎物为食，但它们在夏季和秋季表现出更高的营养生态位重叠，当时所有三个物种都将它们的狩猎行为转变为以少数暂时丰富的飞蛾为食。通过恢复 600 多个猎物物种的 19 个生态特征，我们进一步推断每个蝙蝠物种使用不同的觅食地和狩猎技术，这表明生态位划分主要是栖息地驱动的。两种最密切相关的蝙蝠物种表现出非常不同的觅食栖息地偏好，而第三种，亲缘关系越远的物种越通才。这些结果强调了需要时间全面的样本来充分了解物种共存，并且可以从通过元条形码方法获得的猎物的分类学身份中获得有价值的信息。