A preliminary analysis of the fate of European bumblebees

The authors gathered all the distribution data on European bumblebees (Bombus). The resulting data base includes information on nearly 900.000 specimens from all parts of the West Palaearctic. There are 77 bumblebee species in the studied region, including twelve social obligate parasites (ten from subg. Psithyrus, and two others). Species have been mapped using a 50km UTM grid. Three time intervals have been considered: (i) before 1950, (ii) from 1950 until 1989, and (iii) since 1990. All these maps are available at: http://www.zoologie.umh.
ac.be/hymenoptera/page.asp?id=169.
Based on these maps, it is possible to present a preliminary assessment of the fate of most species using an analysis of the number of squares occupied by each species across the three time periods. The species showing the greatest contraction in range are bumblebees from steppic areas and dry grasslands, and include Bombus armeniacus, B. confusus, B. cullumanus, B. fragrans, B. laesus and B. mocsaryi. Some species from cold areas in high latitudes or altitudes
are also at risk, e.g. B. monticola, B. mesomelas and B. polaris. There is an impoverished area in Western and Central Europe that is roughly defined between the 45° and 55° latitudes. In contrast, there are several species (e.g. B. haematurus, B. hypnorum and B. semenoviellus) that show
a recent and conspicuous range expansion. The observed shifts in many cases are related to the known life history traits of this genus, and the changing environmental conditions in Europe.