| | Insects of Britain and Ireland: the bumblebees and cuckoo bees (Bombus and Psithyrus) |
Red-tailed bumblebee.
Subgenus. Subgenus Melanobombus.
Biology. Social insects forming organized communities; the larvae feeding on pollen and nectar gathered and prepared by the adult females. Nesting underground.
Adult morphology. Females and workers similar in appearance, the males somewhat different (the males with an orange-yellow anterior thoracic band, and the tail one yellower). Adults about 10–23 mm long (queens about 20–22, workers 11–16, males 14–16). The hair coats of abdomen and thorax all black except for a contrasting abdominal tail (females), or not all black anterior to a contrasting abdominal tail (some males). The ocello-ocular area of females shining and unpunctured over only about half the distance between the lateral ocellus and the compound eye, conspicuously punctured with intermixed small and large punctures towards the inner margin of the compound eye. Face relatively short; at least as wide as long, or wider. The facial hairs of males yellow; vertex yellow haired. The facial hairs of females yellow (less bright than in the males); vertex black haired. The mandibles of the females round-ended, not oblique; females with no posterior tooth. Antennae of the male with the third segment at least as long as the fifth; with the third segment considerably longer than the fourth (the 4th only about 2/3 as long). Thorax banded (black with a broad yellow anterior band and a paler posterior one in some males), or not banded (black and unbanded in the females, or occasionally these exhibiting a narrow pale prothoracic band); in males, black across the middle, with pale anterior and posterior bands, or black posteriorly, with a pale anterior band only (occasionally, in females); the light thoracic hairs when banded, in males mid-yellow, or mustard yellow, or pale greyish whitish (the posterior one lighter). 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; pollen basket framed by black 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. Outer surface of the female hind basitarsus densely hairy, the hairs yellowish-white. Scutellum of males black- or predominantly black-haired.
The abdomen black save for the conspicuous orange-red tail, which is paler in the males. Abdomen conspicuously patterned; with a contrasting tail. The tail over tergites 4–6, orange-red. Abdomen conspicuously banded between the anterior of the tail and the thorax (in some males), or without conspicuous banding between the anterior of the tail and the thorax; when banded, in some males with a pale band adjacent to the thorax.
Male genitalia. The sagittae rather straight; smooth to the base, neither serrate nor dentate nor hooked externally; apices minutely capitate and minutely sharply hooked at right angles from the capitulum internally. The ends of the claspers not expanded; dark and horny; small but conspicuously emarginate and toothed (not fringed); with the volsella readily visible at their ends.
British representation. Recorded from England, Wales, Mainland Scotland, Hebrides, Orkney, Channel Isles, and Ireland. Widespread throughout the British Isles. The adults abroad during June to September (males), March to September (females).
Illustrations. • Bombus lapidarius (Red-tailed Bumble-bee: Shaw and Nodder, about 1800). • B. lapidarius: queen and male (photo). • British Bombus spp. (1): Saunders. APIDAE: 1–6, British Bombus species. 1, Bombus sylvarum (female). 2 and 3, B. ruderarius (male and female, respectively). 4, B. pomorum (female). 5 & 6, B, lapidarius (male and female, respectively. 7–10, armature of males: 7, B, sylvarum; 8, B. ruderarius; 9, B. pomorum; 10, B. lapidarius. From Saunders (1896). • Comparing females of B. pascuorum and B. lapidarius with associated Cuckoo-bees (P. campestris and P. rupestris). Comparing female Cuckoo-bees with females of the host Bumblebees. At left, Psithyrus campestris (above) and Bombus pascuorum (below); at right, Psithyrus rupestris (above) and Bombus lapidarius (below). From Saunders, 1896. • Male genital capsules of Bombus and Psithyrus. Male genital capsules of Bombus and Psithyrus, routinely displayed as viewed from below. 1–5, PSITHYRUS. 1, P. rupestris; 2, P. vestalis; 3, P. barbutellus; 4, P. campestris; 5, P. sylvestris. 6–17, BOMBUS. 6, B. muscorum; 7, B. humilis ssp. anglicus; 8, B. pascuorum; 9. B. hortorum; 10, B. subterraneus ssp. latreillellus; 11, B. sylvarum; 12, B. ruderarius; 13, B. pomorum; 14, B. LAPIDARIUS; 15, B. pratorum; 16, B. soroeensis; 17, B. terrestris. Adapted from Saunders (1896), the nomenclature updated.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: the bumblebees and cuckoo bees (Bombus and Psithyrus). Version: 27th July 2019. delta-intkey.com’.
