Bombus ruderatus
Bombs ruderatus is a large size bumblebee (length in queens: 21-24 mm, length in males: 15-17 mm).
It has a very long head, due to its large malar gap, also its labrum's groove is wide and deep. The clypeus is heavily spotted, and the forehead has a thin and regular stipple. The hind legs present a reticulated tibia. Females with genitalia quite similar to Bombus hortorum.
Males present a longer antenna, hind legs with flattened and thin reticulated tibia, with chaeta, whose length is sizeable. Males present genitalia similar to Bombus hortorum, generally very big.
The colour pattern depends on subspecies, but generally black and yellow stripes, with the last stripes white.
The nest of Bombus ruderatus is stablished on the ground or between the vegetation. Its flight period includes from March to September. It shows preferences for the bare lands. Nevertheless, it appears in forests ranges. It has been collected on plants belonging to Fabaceae, Rosaceae, Lamiaceae, Ranunculaceae, Boraginaceae, Escrophulariaceae, Papaveraceae, Oleaceae, and Liliaceae families.
Female: big size, with a long head, due to its malar gap very long, surpassing even A2+3+4. Labrum's tubercles are convex, pointed and dotted. Labrum's groove wide and deep. Convex clypeus, with a dense stipple. Forehead with a thin and regular disposed; the supraorbital line runs just over the lateral ocellus. Hind legs show a crosslinked tibia. The basitarsus, very pubescent. T6 very dotted, conspicuous granulated, with a thick distal edge.
Male: very long head, because the malar gap is like A2+3+4. Long antenna. The hind legs show flattened tibia thin crosslinked; provided of chaetas in its later edge. The basitarsus is wide and robust, and in its wider part, its width is less than that of the tibia. Genitalia similar to that of Bombus hortorum, very large. Simple sagittae, sawn, wider to the base in lateral view. Long and narrow squama, C-shaped, prolonged in two sheets. the bottom of which shows a sawn edge.
Bombus ruderatus is common in western Paleartic, specially in its Mediterranean area. In latitude, its distribution ranges from the Atlas, north Algeria, north Tunisia and south Italy to the south of Sweden, Lithuania and Belarus. To the west, the species extends to the whole Iberian Peninsula, Madeira, the Azores, and England. It is very rare in Wales and probably absent from Ireland. The eastern limit of its range is less clear, though it includes Poland, Hungary and Slovakia and seems to reach Ukraine.
Potential distribution map at the present time
Potential distribution map in 2050 with the same level of pollution emission and the climate changes consequence of these contamination levels
Map legend
Maps are made with GBIF data of this specie in Iberian Peninsula
It inhabits bare lands mainly, but it appears also in forests.