Bombus modestus is a taiga species, like B. cingulatus, B. sporadicus, B. semenoviellus, B. schrencki and B. patagiatus. However, it is far less common than these and is, indeed, among the rarest and less known species of the West-Palaearctic region. Only few specimens have been collected in Europe. More east, it is known from western Siberia to Far-East to the East.
P. Rasmont