Black oil beetles are large and flightless beetles that live in sun-exposed flower meadows. The larvae of black oil beetles climb on wild flowers to hitchhike on solitary bees and live in beehives as parasites, eating honey, larvae and eggs.
If you encounter a black oil beetle waddling on sand, it is best to leave it alone because they emit poisonous fluid from the joints of their feet if they are disturbed.
There are two black oil beetle species in Finland, the more common violet oil beetle (Meloe violaceus) and the near threatened European oil beetle (Meloe proscarabeus) that lives in Kakslammi.
Spring is the best time to spot the European oil beetle, which can grow up to four centimeters long. Such a beetle has been spotted on this slope as early as the beginning of April.