The dataset consist on abundance values of madicolous insects - aquatic organisms that inhabit thin layers of water - recorded in three mountains of the Atlantic Rainforest (G1, G2, and G3) and in one Amazon mountain (G4). The distribution of sampling sites cover the full elevational range of each region, from 0 to 2,800 m a.s.l. in the Atlantic Forest and from 90 to 3,000 meters a.s.l. in the Amazon. A total of 109 sampling sites were investigated, where physico-chemical parameters of water (temperature, pH, dissolved oxygen and conductivity), geographic coordinates and the altitude were also obtained.

Adults of madicolous insects were sampled with emergence traps (0.125 m² coverage area), and immatures with hand net (250 µm mesh size) in the same sites were adults were collected. All individuals were identified to the lowest taxonomic resolution possible (genus, species or morphospecies). Water physico-chemical parameters were determined with an analytical kit and conductivity was measured with a portable conductometer. Geographic coordinates and the altitude of each sampling site were obtained in the field with GPS.