British Insects: Bumblebees and Cuckoo-bees
B. lapponicus (misident.), subspecies scoticus Pittioni.
Subgenus. Subgenus Pyrobombus.
Biology. Social insects forming organized communities; the larvae feeding on pollen and nectar gathered and prepared by the adult females.
Adult morphology. Females and workers similar in appearance, the males somewhat different (male thorax blacker in the middle and with paler yellow bands, the abdomen more conspicuously black-banded anteriorly and redder posteriorly). Adults about 12–18 mm long (queens about 16 mm, workers 12 mm, males 14 mm). The ocello-ocular area of females mostly shining and unpunctured, except for sparse puncturing along the inner margin of the compound eye. Face relatively long; at least as wide as long, or wider. The facial hairs of males yellow; vertex yellow haired. The facial hairs of females black; vertex yellow haired. The mandibles of the females round-ended, not oblique; females with no posterior tooth. Thorax not predominantly ginger-haired; banded; black across the middle, with pale anterior and posterior bands (black, banded lemon-yellowish fore and aft, the rear band broadly C-shaped and more or less as wide laterally as in the middle); the light thoracic hairs lemon-yellow. The outer surface of the hind tibiae of females with a conspicuous pollen basket, in the form of an elongate, shiny, hairless, area framed by stout hairs. The hind tibiae of the males having a fringe of long hairs along the outer margin. Mid basitarsus of females with the distal-posterior margin broadly rounded to narrow, but if pointed forming an angle of more than 45 degrees, not projected into a tooth or spine. Scutellum of females at least partly pale-haired. Scutellum of males pale- or predominantly pale-haired.
The abdomen of females black or yellow adjacent to the thorax, otherwise gingerish red; in the males conspicuously black-banded over the proximal third, otherwise bright orange-red thence to the tip of the tail. Abdomen conspicuously patterned; with a contrasting tail. The tail orange-red (occupying tergites 2–6, i.e about half the length of the abdomen, tending to yellowish laterally on tergites 4 and 5). Abdomen conspicuously banded between the anterior of the tail and the thorax, or without conspicuous banding between the anterior of the tail and the thorax; with a pale band adjacent to the thorax, or with one or two faint pale bands between the interrupted anterior black one and the tail (tergite 1 of females black or yellow). Tergite 2 of females reddish orange.
Male genitalia. The sagittae rather straight; smooth to the base, neither serrate nor dentate nor hooked externally; apices apically turned inwards and conspicuously sickle-shaped. The ends of the claspers not expanded; dark and horny; not or only slightly emarginate, without teeth; with the volsella inconspicuous (fairly).
British representation. Recorded from England, Wales, Mainland Scotland, and Ireland. Mainly uplands of Scotland, Wales, and northern and midlands England, absent from eastern and southeastern England; in Ireland restricted to the north and south-east. The adults abroad during April to September (females), or July to September (males). Mostly a montane and moorland species, often associated with Vaccinium.
General comments. The adults of B. monticola and B. pratorum are scarcely distinguishable morphologically, but B. pratorum is less red in the tail and the pale banding is mid-yellow, by contrast with the lemon-yellow of B. monticola.
Illustrations. • British Bombus spp. (2): Saunders. • Male genital capsules of Bombus and Psithyrus.
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Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: Bumblebees and Cuckoobees. Version: 1st January 2012. http://delta-intkey.com’.