LAUSR

Abstract Background Protected areas are unique ecosystems that are minimally affected by anthropogenic activities. Therefore, in many cases, they are refugia and relevance of faunistic research is undeniable here. A simple method of catching insects, such as trapping with the help of fermental traps, was used in this area for the first time. The authors of the dataset used this method from 2018 to 2021. One thousand and fifty-one traps of our own design were installed. The dataset includes data on 367 species from 52 families (6,497 records of 44,600 specimens). Ten species were dominant in the traps (Cryptarchastrigata, Protaetiamarmorata, Glischrochilusgrandis, Glischrochilushortensis, Soroniagrisea, Rhagiummordax, Lepturathoracica, Lepturaquadrifasciata, Quediusdilatatus and Protaetiafieberi). These species accounted for 76.9% of all individuals in the total amount of captured specimens. Cryptarchastrigata was the most numerous species (28.8% of the total) and the most frequently encountered species (64.9%). The greatest species diversity was recorded in the families Cerambycidae (53 species), Elateridae and Curculionidae (39 species each), Nitidulidae and Coccinellidae (22 species each). The dataset contains information on the occurrence of 15 rare species. New information We have recently published a checklist of the Coleoptera of Mordovia State Nature Reserve (Egorov et al. 2020). It included 2,145 species from 88 families. However, the published list did not contain information about the occurrence of various species of beetles, especially caught in recent years. Part of this list contained information about species collected using fermental traps. However, the list of species did not provide information about specific locations.