Land cover influences dietary specialization of insectivorous bats globally

Land-use changes are a leading cause of biodiversity loss and ecosystem service degradation worldwide, but these changes do not affect all organisms equally. Understanding factors influencing resistance to environmental change is vital for informed conservation. In particular, dietary generalists may withstand environmental change better than specialists due to their ability to exploit variable resources. Bats are voracious insectivores, but vary widely in their degree of dietary specialization. Here, we analyze the effect of land cover and morphology on dietary diversity and the two most common prey items on which bats specialize (Lepidoptera and Coleoptera), selecting important independent variables using phylogenetic generalized least squares and model selection. Dietary diversity increased with increasing amount of cropland near the study area, consumption of Lepidoptera decreased with increasing habitat diversity, and consumption of Coleoptera decreased with increasing distance from the equator. Biodiversity (and hence, prey diversity) is expected to decrease with agricultural intensity, but the observed pattern suggests dietary specialists may avoid agricultural habitats due to lack of preferred prey. Dietary specialists may thus be increasingly at risk as agricultural intensity increases around the world, and it is essential that we continue to document their ecological roles and the services they provide to society.