Stoneflies from Assis Ecological Station, western São Paulo state, Brazil: new geographic records and nymph–adult association using laboratory rearing and molecular tools

The mountainous regions of eastern São Paulo are well-studied for Plecoptera due to the large areas of preserved Atlantic Forest. On the other hand, the western region remains poorly studied, despite the intense agricultural use. To address this gap, this study focuses on the Plecoptera fauna of the Assis Ecological Station (EEA) in western São Paulo state, Brazil, which is a region previously understudied for these insects and is embedded within an agricultural matrix. At the EEA, specimens were collected from 2018 to 2023 using various methods and studied considering morphological and molecular methods. Notable findings included new geographic records and life-stage associations through immature rearing and a molecular approach. We recorded the occurrence of Anacroneuria ofaye and Tupiperla gracilis, and associated the nymphs of two morphospecies of Anacroneuria and T. gracilis. This study contributed to the taxonomy of Plecoptera, highlighting the importance of documenting and understanding biodiversity, and of intensifying efforts to overcome shortfalls in taxonomic, distributional and life stage knowledge of these aquatic insects, mainly in western São Paulo state.