Vertical stratification and seasonality of fruit-feeding butterfly diversity in a Neotropical dry forest

Vertical stratification and climatic seasonality influence the structuring of butterfly communities in tropical forests. This study assessed how vertical stratification (canopy vs. understory) and seasonal variation affect fruit-feeding butterfly (Nymphalidae) assemblages in a Brazilian tropical dry forest (TDF), and how these patterns relate to climatic variables and food resource availability. Sampling was conducted monthly over one year in the northern Espinhaço Range, within the Caatinga domain. Twenty 25 × 4 m plots were established, each with two Van Someren-Rydon traps (understory at 1 m and canopy at ≥ 6 m). Monthly measurements included temperature, humidity, light, precipitation, and zoochoric fruit availability. We recorded 2,166 individuals from 51 species, with Biblidinae and Satyrini representing over 70% of the community. Hamadryas februa was dominant in the understory, while Biblis hyperia nectanabis prevailed in the canopy. Species composition differed between vertical strata, indicating niche partitioning likely driven by microclimatic variation. Temporal patterns also influenced diversity: species richness peaked during the hottest months, and abundance peaked in the driest month, about two months after the rainy season's peak. Subfamilies and tribes showed distinct seasonal peaks, suggesting temporal niche partitioning and reduced intergroup competition. Our findings highlight that vertical and seasonal gradients shape butterfly communities in TDFs. The high diversity and spatial-temporal dynamics observed emphasize the ecological value of the Caatinga and the need to consider vertical structure and seasonality in conservation strategies for TDFs, highly threatened and understudied ecosystems in Brazil.