Metadata for: Molecular diet barcoding reveals fine-scale diet variation in proboscis bats (Rhynchonycteris naso) of Belize

Insectivorous bats play key roles in tropical food webs, yet fine-scale dietary variation remains poorly documented for most Neotropical species. We used fecal DNA metabarcoding to examine spatial and temporal patterns in the diet of the proboscis bat (Rhynchonycteris naso), a widespread emballonurid that forages exclusively over water. We analyzed 65 fecal samples collected from three roosts along the New River Lagoon and its tributaries in northwestern Belize over three field seasons (2021–2023). Prey DNA was amplified using cytochrome oxidase I (COI) primers and sequenced on an Illumina MiSeq platform, yielding molecular operational taxonomic units (MOTUs) representing prey diversity. Overall prey richness (Shannon diversity) did not differ significantly among roosts, but prey composition showed significant site-specific structuring. Permutational multivariate analyses indicated that roost location explained more dietary variation than season, sex, or year. These results demonstrate that R. naso exhibits fine-scale trophic differentiation across habitats separated by only a few kilometers, likely reflecting local vegetation structure and insect availability. Our study provides the most comprehensive dietary profile of this species to date and highlights the importance of habitat heterogeneity for shaping trophic interactions in Neotropical bat communities.