Prey-mediated ecological pathways shape dietary niche structure across environmental gradients in the great Himalayan leaf-nosed bat (Hipposideros armiger)

The analysis of the mechanisms underlying environmental gradient-mediated intraspecific dietary variation can aid in predicting species responses to ecological change. According to the niche variation hypothesis (NVH), broad population niche widths arise primarily from individual-level specialization. However, the underlying ecological pathways are not well understood, especially for highly mobile predators. This study tested NVH in the widespread insectivorous bat Hipposideros armiger using a multi-population, integrative framework. Dietary DNA metabarcoding, morphological trait analysis, acoustic monitoring, and environmental data analyses were performed to examine dietary composition, niche breadth, and individual specialization across spatial gradients.Our investigation revealed three key findings: (1) Geographic variation in dietary assemblages was significantly driven by spatial turnover in prey communities. (2) Populations with broad dietary niches consistently exhibited increased among-individual specialization, supporting the NVH. (3) Structural equation modeling demonstrated a hierarchical ecological pathway, linking broad-scale environmental gradients to prey community turnover, individual-level foraging specialization, and population-level dietary diversity. This prey-mediated ecological framework reveals that environmental heterogeneity exerts cascading effects through trophic interactions to shape within-species functional variation. This dataset contains the original DNA metabarcoding data of all bat samples in this study. All the data is saved in a compressed package