Tropical dry forests are characterized by punctuated seasonal precipitation patterns that drive primary production and the availability of fruits, seeds, flowers, and insects throughout the year. In environments in which the quantity and quality of food resources varies seasonally, consumers should adjust their foraging behavior to maximize energy intake while minimizing overlap with competitors during periods of low food availability. Here, we investigated how the diets of frugivorous bats in tropical dry forests of NW Mexico varied in response to seasonal availability and how this affected dietary overlap of morphologically similar species. We performed stable isotope analyses to understand temporal and interspecific patterns of overall isotopic niche breadth, trophic position, and niche overlap in the diet of six frugivorous species of closely related New World leaf‐nosed bats (family Phyllostomidae, subfamily Stenodermatinae). We estimated seasonal changes in resource abundance in two complementary ways: (a) vegetative phenology based on long‐term remote sensing data and (b) observational data on food availability from previously published insect and plant fruiting surveys. In all species, there was a consistent pattern of reduced isotopic niche breadth during periods of low food availability. However, patterns of niche overlap varied between morphologically similar species. Overall, results from our study and others suggest that seasonal food availability likely determines overall dietary niche breadth in Phyllostomidae and that despite morphological specialization, it is likely that other mechanisms, such as opportunistic foraging and spatiotemporal niche segregation, may play a role in maintaining coexistence rather than simply dietary displacement.

中文翻译：

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共存的新热带节食蝙蝠（Stenodermatinae）中的季节性饮食生态位收缩

热带干燥森林的特征是季节性的降雨出现点缀，这驱动了全年的初级生产以及水果，种子，花朵和昆虫的供应。在食物资源的数量和质量随季节变化的环境中，消费者应调整其觅食行为，以最大程度地吸收能量，同时在食物供应量较低的时期，最大程度地减少与竞争对手的重叠。在这里，我们调查了墨西哥西北部热带干旱森林中节食蝙蝠的饮食如何随季节的变化而变化，以及这如何影响形态相似物种的饮食重叠。我们进行了稳定的同位素分析，以了解总体同位素生态位宽度，营养位置，六个紧密相关的新大陆叶鼻蝙蝠（Phyllostomidae家族，Stenodermatinae家族）的六种食肉物种的饮食中的生态位和重叠位。我们以两种互补的方式估算了资源丰富度的季节性变化：（a）基于长期遥感数据的植物物候学和（b）先前发表的昆虫和植物结果调查中有关食物供应的观测数据。在所有物种中，在食物供应不足期间，同位素生态位宽度减小的趋势一致。但是，生态位重叠的模式在形态相似的物种之间有所不同。总体而言，我们的研究和其他研究结果表明，季节性食物的供应量可能决定了竹节虫科的整体饮食生态位宽度，尽管形态学专门化，但其他机制，