Seasonal variation of insect assemblages in a protected area of the Caatinga, northeastern Brazil

The Caatinga, the largest seasonally dry tropical forest in the Neotropics, is characterized by pronounced hydric seasonality, which regulates the dynamics of its biological communities. This study was conducted in the Contendas do Sincorá National Forest (FLONA-CS), Bahia, northeastern Brazil, from November 2023 to August 2025, using Malaise traps deployed in two distinct phytophysiognomies. A total of 7,493 specimens belonging to 14 insect orders were collected, with Diptera predominating (71%), followed by Lepidoptera, Coleoptera, and Hymenoptera. Total abundance varied among seasonal sampling events, with maxima in spring and summer 2024 (2,822 and 2,026 individuals, respectively) and minima during winter sampling events (236 in 2024 and 267 in 2025). Spring 2023 differed from the subsequent spring in both composition (Lepidoptera predominance) and lower rainfall; this period coincided with the 2023–2024 El Niño warm phase. Correlation and multiple regression analyses suggested that rainfall was positively associated with abundance in several groups (e.g. Diptera, Hemiptera, and Coleoptera), whereas temperature was positively associated with thermotolerant groups such as Formicidae and Blattodea. Overall, a quantitative seasonal baseline for flying insect assemblages in a protected Caatinga area is provided, offering a reference for long-term monitoring and future interannual comparisons.