The range of Bombus ruderarius extends over a large part of the West-Palaearctic region.
In the Iberian peninsula, it is found in the northern mountain ridges, where the form montanus coexists with the nominal subspecies. The nominal subspecies is present in Ireland, Great-Britain and in Fennoscandia, around the Gulf of Bothnia, where it reaches the Arctic Circle. In Russia, the nominal subspecies and the form montanus are found, grossly, between the 50th and 60th parallels. The eastern limits of the species are in SW. Siberia and in the mountains of E. Turkestan (ssp. sartus). Southwards, the range of B. ruderarius extends to the south of the Italian peninsula and in the Balkan, to the Parnassos Mt. (Greece) without including, however, the Mediterranean littoral and the large Mediterranean islands. The subspecies B. ruderarius tunensis is endemic to E. Algeria and N. Tunisia. The nominal subspecies is found in W. Anatolia, whereas B. ruderarius simulatilis lives in the mountains of Anatolia, the Caucasus region and N. Iran. There appears to be a wide discontinuity between the populations of this region and those of the S. Russia plains.
As it is for B. sylvarum, the distribution of B. ruderarius is patchy; ranging from very rare (as in N. Africa), to very common : in some places of the E. Pyrenees, the species may account for more than the half of all the observed bumblebees .
P. Rasmont