Polskie Pismo Entomologiczne
Bumblebees inhabit cooler regions of the temperate climatic zone. This is confirmed by studies on their species diversity. However, little is known about abundance in various latitudes. Recently, bumblebee densities have been evaluated in agricultural ecosystems in Poland, Rumania, Bulgaria, Germany, Belgium and southern France. Results of these studies suggest a clear correlation between the density and the value of the thermal continentalism coefficient (CTC) in Europe: the bumblebee density increases with the increase in the effect -of oceanic climate (hypothesis of oceanic-continental gradient of bumblebee density). In N and W Poland, where CTC is below 43%, the bumblebee density is considerably higher (over 2000 indiv./ha) than in the SE areas (below 1000 indiv./ha) where the influence of continental climate is stronger. Similarly, low values of bumblebee density were observed in the lowland regions of Rumania and Bulgaria, where CTC value is close to 60%.
Banaszak, Jozef, "Variability in density of bumblebees in Europe (Hymenoptera: Apoidea: Bombus Latr.)" (1996). An. Paper 202.
Available for download on Friday, January 01, 4500