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Montana Animal Field Guide

Montana Field Guides

Black Tail Bumble Bee - Bombus melanopygus
Other Names:  Pyrobombus melanopygus


Global Rank: G4G5
State Rank: SNR

Agency Status
USFWS:
USFS:
BLM:


 

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General Description
For definitions and diagrams of bumble bee morphology please see the Montana State Entomology Collection's Bumble Bee Morphology page. Small body size, queens 16-19 mm, workers 10-16 mm; face square, of medium head length with cheek as long as wide, tongue length medium; basitarsus of mid-leg with back far corner rounded, outer surface of hind-leg tibia flat and without hair but with a fringe of hair forming a pollen basket; hair length medium and uneven, hair yellow on face and top of head, thorax with many black hairs densely mixed in front pale band, the black band between the wings not sharply defined, the back area of thorax variably yellow; T1 yellow, T2-3 orange (sometimes with black hairs intermixed), T4-5 black (often with yellow intermixed); if T2-3 extensively black then T4-5 extensively yellow and T5 yellow on sides. Males 11-14 mm, eyes similar in size and shape to any female bumble bee; antenna medium in length, flagellum 3x longer than the scape; color pattern similar to queen and worker (Koch et al. 2012, Williams et al. 2014)

Phenology
Queens active February to August, workers and males March to September (Koch et al. 2012, Williams et al. 2014). In California, queens active early February to early October, workers late April to late September, males late June to early October (Thorp et al. 1983).

Diagnostic Characteristics
Please see the Montana State Entomology Collection's Key to Female Bumble Bees in Montana. Distinguished from other Bombus by combination of outer surface of hind-leg tibia concave and forming a pollen basket, anterior edge of thorax (scutum) to the distinct black band between the wings with mix of yellow and black hairs giving a cloudy appearance, T2-3 with red or orange hairs (T2 not intermixed with yellow) and corbicular (pollen basket) fringe hairs black (or possibly orange at the tips).

Species Range
Resident Year Round

Recorded Montana Distribution

Click the map for additional distribution information.
Distributional Information Provided in Collaboration with the
Montana Entomology Collection at Montana State University
MTEC at MSU

 


Range Comments
Occurs in the Sierra Nevada and Cascade ranges in the west to the Rocky Mountains in the east, from Alaska and boreal treeline across Canada to the Mexico border (Koch et al. 2012, Williams et al. 2014). Absent from the southwestern deserts and high desert regions, with isolated occurrences in the Alaskan and eastern Arctic and western Nebraska. In Colorado, primarily above 2500 m elevation, but ranging to 4300 m (Macior 1974). In Montana, present in the mountains of the western third of the state. Considered common through much of its range.

Habitat
Predominantly open grassy areas and mountain meadows, but also sagebrush steppe to alpine fell-field and tundra (Macior 1974, Bauer 1983, Shaw and Taylor 1986, Cook et al. 2011, Williams et al. 2014). In southern Alberta, B. melanopygus is found in foothill and mountain forest zones (Hobbs 1967). In southern Idaho, trapped significantly more often in areas with sagebrush canopy < 10% than where canopy > 25% (Cook et al. 2011). Also frequents commercial highbush blueberry and cranberry crops in southern British Columbia (Ratti et al. 2008). Two nests in southern Alberta were constructed in woods-meadow ecotone (Richards 1978).
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habit Model available.

To learn how these Models were created see http://mtnhp.org/models

Food Habits
Feeds on a wide variety of flowers, including Allium, Anaphalis, Arctostaphylos, Arenaria, Castilleja, Ceanothus, Dodecatheon, Ericameria, Erigeron, Eriogonum, Haplopappus, Iris, Linaria, Lupinus, Mertensia, Myosotis, Oxytropis, ,i>Pedicularis, Penstemon, Phacelia, Polygonum, Rhododendron, Rubus, Salix, Salvia, Sedum, Taraxacum, Trifolium, Vaccinium, and Wyethia (Macior 1974, Bauer 1983, Shaw and Taylor 1986, Wilson et al. 2010, Williams et al. 2014).

Reproductive Characteristics
One of the earliest bumble bee species to begin nesting and produce males. Nests built underground, and sometimes above ground in bird houses and building insulation (Williams et al. 2014). Underground nests favored in southern Alberta (Hobbs 1967); two nests were begun 7 June. Two other nests in southern Alberta were started on 8 and 10 May (Richards 1978). Nest parasitism by cuckoo bumble bees has not been described.

References
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Citation for data on this website:
Black Tail Bumble Bee — Bombus melanopygus.  Montana Field Guide.  .  Retrieved on , from