This study investigated the seasonal activity of Carabus coriaceus imagos in the eastern portion of their distribution range, particularly in mixed and pine forests located in the Mordovia State Nature Reserve and National Park “Smolny” (Republic of Mordovia). The period of activity varied between years, commencing in late April in 2018 and early May in 2019, and extending until mid-September and October. Population density peaked between mid-July and August. The warmer spring of 2018 led to an earlier start of activity, whereas the colder spring of 2019 delayed the appearance of ground beetles until early May. Capture rates were significantly higher in the Mordovia State Nature Reserve than in the National Park “Smolny,” which is likely due to the long-term ecological protection of the reserve. With more than 80 years free from anthropogenic disturbances, the ecosystems in this area have undergone complete recovery.
