The eleven sampling monitoring sites (mountains): 1 Western Stara Planina, 2 Central Stara Planina, 3 Eastern Stara Planina, 4 Vitosha, 5 Osogovo, 6 Belasitsa, 7 Rila, 8 Pirin, 9 Western Rhodopes, 10 Eastern Rhodopes, 11 Strandza.

 
 
  Part of: Antonova V, Marinov MP (2021) Red wood ants in Bulgaria: distribution and density related to habitat characteristics. Journal of Hymenoptera Research 85: 135-159. https://doi.org/10.3897/jhr.85.61431