Bombus ruderatus (Fabricius)

Weissmann, Julie A., Picanco, Ana, Borges, Paulo A. V. & Schaefer, Hanno, 2017, Bees of the Azores: an annotated checklist (Apidae, Hymenoptera), ZooKeys 642, pp. 63-95 : 69-70

Bombus ruderatus (Fabricius)

Description.

Large black bee; wing length 18 mm and total length up to 22 mm in queens, workers with wing length of 13 mm and total length up to 16 mm, males with wing length of 14 mm; queens and workers with two brownish-yellow bands on the thorax, a narrow yellow band and white tip of the abdomen (Fig. 3a, c); males with paler yellow bands, more white abdomen and white hairy face pattern (Fig. 3e).

Distinguishing features.

Of the two bumblebee species in the archipelago, Bombus ruderatus is the paler species and can be recognized by the different colour pattern (two yellow bands on the thorax vs. one yellow thorax band in Bombus terrestris ).

General distribution.

Madeira; throughout Europe from the Iberian Peninsula to southern Scandinavia; North Africa; Asia to Siberia in the East; introduced and invasive in New Zealand and South America (Chile, Argentina).

Distribution in the Azores.

All islands.

First record.

1865 ( Godman 1870, as Bombus hortorum ).

Nesting.

Colonies of up to 50-100 workers in existing holes in the ground.

Social behaviour.

Primitively eusocial.

Foraging.

Polylectic, visits a wide range of species, including exotic invaders like Lantana camara , Verbenaceae (Fig. 3e).

Phenology.

All year.

Material.

Faial (Horta), August-September 1930, leg. L. Chopard, det. Benoist ( Benoist et al. 1936, not seen) Faial (Castello Branco, from Japanese beetle trap), 1999, 1 worker, 9 males, leg. H. Schaefer, coll. TUM (specimens B48-B49, B52-B56, B63-B64, B72).

COI sequences of specimens B63-64 (TUM), acc. no. KX824771-72, are identical to Bombus ruderatus sequences from Portugal and UK in GenBank (see Fig. 2).

Note.

Reports of Bombus hortorum L. by Benoist et al. (1936) refer to this species.