SPECIES FACT SHEETScientific Name: Bombus vagans Smith, 1984Common Name(s): Half-black bumble beePhylum: ArthropodaClass: InsectaOrder: HymenopteraSuborder: ApocritaFamily: Apidae

Synonyms: Bombus bolsteri Franklini 1913 (Hatfield et al. 2015b)Conservation Status:

Global Status: G4 (last reviewed 07 April 2018)National Status (United States): N4? (21 June 2010)State Statuses: SNR (OR); S2? (WA)(NatureServe 2018)

Federal Status (United States): Not listed (USFWS 2019)IUCN Red List: Least Concern (IUCN 2015)

Taxonomic Note:

Bombus vagans and B. bolsteri are considered synonymous by Williams et al. (2014). Bombus cockerelli is possibly synonymous to B. vagans however further genetic work is needed to assess whether it is conspecific (Williams et al. 2014).

Technical Description:

Bumble bees (Tribe Bombini, Genus Bombus) are large bodied (ranging in size from 9 to 27 mm), bombiform in shape, and generally covered in brightly colored, dense hairs (Michener 2007; Thorp et al. 1983; Williams et al. 2014). They can be distinguished from other large-bodied bees in the Anthophorini or Eucerini tribes by the long cheeks (malar spaces) on the face and pollen baskets (corbicula) on the hind tibiae of most females (Michener 2007). Carpenter bees in the tribe Xylocopini are also large-bodied and sometimes mistaken for bumble bees, although most carpenter bees have shiny abdomens and lack the dense abdominal hairs that bumble bees possess. Carpenter bees are rare in Oregon and Washington; records from Oregon are largely confined to Klamath, Jackson, Josephine, and Wallowa

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counties, and they have not been detected in Washington (Discover Life 2013).

Bombus vagans, a member of the Pyrobombus subgenus, has hair color patterns that can be used to distinguish this species from other Bombus species in the field. The species most similar to B. vagans and with overlapping ranges in Oregon and Washington are B. flavifrons, B. rufocinctus, and B. morrisoni (Koch et al. 2012; Williams et al. 2014; Xerces Society et al. 2019). Identifying features for B. vagans are noted in the detailed description below (descriptions compiled from Williams et al. 2014 and Koch et al. 2012).

Queens and Workers: Bombus vagans queens and workers are similar in coloration. The queen is 17 to 21 mm in length, whereas the worker is 11 to 14 mm in length. Their hair is long. The hair of the head is usually black, but the vertex (top of the head) has intermixed yellow hairs with yellow hairs at the antennal base. The hair on the top and sides of the thorax is yellow, with a black spot between the wings. The spot may be small and intermixed with yellow (especially in queens) or larger and diffuse sometimes forming a band (especially in workers). The first two tergal (dorsal plate) segments on the abdomen are yellow. Tergal segments 3 through 6 (T3-T6) have black hairs. In addition to color patterns, there are morphological differences between these species. Bombus vagans has a medium head with a cheek just longer than broad (contrast B. rufocinctus). Bombus vagans females have a rounded corner on the distal posterior corner of their midleg basitarsus.

Males: Male B. vagans are similar in coloration to workers and queens. The male is 11 to 14 mm in length. The hair on the top of the thorax is predominantly yellow, occasionally with black hairs mixed between the wing bases without a distinct black band between the wings. The hair on the first and second tergal segments is almost entirely yellow. The third tergal segment is usually black, T5-T6 often with yellow laterally. The eyes of male B. vagans are similar to females in both size and shape (contrast B. rufocinctus). Generally, male bumble bees can be more difficult to identify than female bumble bees, and often require inspection of genital morphology (see Williams et al. 2014 for more

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detail). When in doubt, consult with a trained taxonomist; collecting specimens is recommended (see survey protocol).

Life History:

Most species of bumble bees are primitively eusocial insects that live in colonies made up of one queen, female workers, and, near the end of the season, reproductive members of the colony (new queens, or gynes, and males). New colonies are initiated by solitary queens, generally in the early spring. This process includes locating a suitable nest site; collecting pollen and nectar from flowers; building a wax structure to store nectar; forming a mass of pollen to lay eggs on; and building a wax structure to enclose the eggs and pollen. A complete understanding of B. vagans nesting habits is unavailable, but generally this species will nest underground (e.g., abandoned rodent nests) or sometimes aboveground (e.g., tufts of grass, old bird nests, rock piles, or cavities in dead trees) (Williams et al. 2014; Hatfield et al. 2015b). Once the colony has been initiated by the queen and the first brood of female workers have grown, pupated, and emerged as adults, the female workers take over all duties of foraging for pollen and nectar, colony defense, nest temperature regulation, and feeding larvae. The queen’s only responsibility at this point is to lay eggs (Goulson 2010). The average size of B. vagans colonies has not been well documented in the published literature, but average Bombus spp. colony sizes range from 100-400 workers – though there are species with exceptionally large colony sizes (>1,000), and exceptionally small colony sizes (<50) (Goulson 2010).

Bumble bees, including B. vagans, are generalist foragers and have been reported visiting a wide variety of flowering plants. Bombus vagans has a medium tongue length. According to Williams et al. (2014), important food plants for B. vagans are in the genera Aster, Chelone (turtlehead), Cirsium (thistle), Impatiens (jewelweed), Lonicera (honeysuckle), Monarda (bee balm), Prunella (selfheal), Solidago (goldenrod), Trifolium (clover), Vicia (vetches), and Viola (violet).

In the late summer or fall, depending on the bumble bee species and elevation, colonies produce reproductive individuals (males and gynes), which leave the colony and mate. As winter approaches, the old queen,

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workers, and males die, while the gynes continue to forage and search for a suitable location (hibernacula), usually burrowed a few centimeters underground, in which to spend the winter. The newly mated queens store sperm until they initiate a colony the following spring.

According to Williams et al. (2014), the flight period for B. vagans queens ranges from March through early October, peaking in late May and early June. The flight period for workers is from early April to mid-October with a peak in August; the male flight period is from May to early-November, with a peak in early September (Williams et al. 2014).

Range, Distribution, and Abundance:

Type Locality: The specific locality for B. vagans is not described in detail. A vague habitat locality description lists North America (Smith 1854).Range: Bombus vagans has a wide distribution in North America and occurs primarily in Boreal Forest and Temperate Forest regions in eastern Washington east to New England (Koch et al. 2012; Williams et al. 2014). This species occurs at higher elevations along the Appalachian Mountains and west through the Great Plains to Washington and British Columbia (Williams et al. 2014).

Distribution: Recent survey efforts by citizen scientists participating in Bumble Bee Watch and the Pacific Northwest Bumble Bee Atlas have nearly doubled the number of B. vagans records in the Pacific Northwest. In 2017 and 2018 alone, 72 B. vagans records have been reported for Oregon and Washington using these platforms.

In Oregon, this species is known from the northeast corner of the state near Encina and Baker City (Baker County), near the Wallowa River (Wallowa County), and from roadside areas and Glass Hill in Union County.

In Washington, this species is known from Walla Walla and Fort Walla Walla Park (Walla Walla County); Moscow Mountain, Kamiak Butte County Park, and the near the cities of Pullman and Diamond (Whitman County); near Rooster Comb (Chelan County); near the city of Spokane, Cliff Park, Antoine Peak Conservation Area, Silver Hill, and Clear and Lonelyville Lakes (Spokane County); near the city of Davenport, Long Lake Dam Park, and near Coffeepot and Wall Lakes (Lincoln County); near Saddle Mountain, on the Kalispel Reservation, and on the Sullivan Lake Ranger Station (Pend Oreille

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County); near Paint Rock and Vulcan Mountain (Ferry County); near Ann Lake (Ferry County); near the city of Rice, near Swede Hill, and Williams, Hyatt, and Little Pierre Lakes (Stevens County); and near the town of Oroville, Blue Goat Mountain, and Stadium Lake (Okanogan County).

BLM/Forest Service Land:

Documented: Bombus vagans has been documented on the Wallowa-Whitman National Forest near Bonneville Mountain in Wallowa County, Oregon. It has also been documented on the Okanogan-Wenatchee National Forest near Anne Lake in Chelan County and on the Colville National Forest on the Sullivan Lake Ranger Station Pollinator Patch (Pend Oreille County) and near Little Vulcan Mountain (Ferry County) in Washington.

Suspected: Due to the close proximity of records, this species is suspected on the Umatilla National Forest in Union and Umatilla Counties, Oregon, and in Walla Walla and Whitman Counties, Washington. Bombus vagans is also suspected on Spokane (Okanogan, Lincoln, and Douglas Counties) and Vale-OR (Baker County) BLM District Land due to the close proximity of occurrence records.

Abundance: Abundance estimates for B. vagans are limited. NatureServe (2018) lists this species as apparently secure (G4). Within its range B. vagans appears to be common (Koch et al. 2012; Hatfield et al. 2015b), however this species has not been ranked (SNR) in Oregon and is considered imperiled (S2?) in Washington (NatureServe 2018). Although there are limitations and restrictions with the currently available data in the western part of its range, it appears that B. vagans has not experienced a decline in range, persistence, or relative abundance but has experienced declines at local levels in some regions (Hatfield et al. 2015b).

Habitat Associations:

Bumble bees inhabit a wide variety of natural, agricultural, urban, and rural habitats, although species richness tends to peak in flower-rich meadows of forests and subalpine zones (Goulson 2010). Like most other bumble bees, B. vagans has three basic habitat requirements: suitable nesting sites for the colonies, nectar and pollen from floral resources available throughout the duration of the colony period (spring, summer and fall), and suitable

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overwintering sites for the queens. Bombus vagans occupies a wide range of habitats including forests, wetlands, urban parks, and gardens and is likely to be found utilizing early spring ephemerals (Williams et al. 2014; Hatfield et al. 2015b).

Nest Sites: Reports of B. vagans nests are primarily underground and can occasionally be found aboveground (Williams et al. 2014). Male B. vagans can be found patrolling circuits or a specific route in search of new queens with which to mate (Williams et al. 2014).

Floral Resources: Bumble bees require plants that bloom and provide adequate nectar and pollen throughout the colony’s life cycle. This activity period can vary by elevation, but can occur from late April to early November for B. vagans. The amount of pollen available in the landscape directly affects the number of new queens that a bumble bee colony can produce, and since queens are the reproductive members of the colony, pollen availability is directly related to future bumble bee population size (Burns 2004). Early spring and late fall are often periods with lower floral resources; the presence of flowering plants at these critical times is essential.

Bombus vagans, like other Bombus spp., is a generalist forager. Plant associations for this species in the West are somewhat scarce, but documented associations include: Aralia hispida (bristly sarsaparilla), Chelone glabra (white turtlehead), Clinopodium vulgare (wild basil), Hydrophyllum virginianum (Virginia waterleaf), Pontederia cordata (pickerelweed) (Xerces Society et al. 2019), Penstemon (beardtongue), Asclepias (milkweed), Aster, Cirsium (thistle), Eupatorium (boneset), and Spiraea (spirea) (Koch et al. 2012). Additionally, Williams et al. (2014) report plants in the genera Chelone (turtlehead), Impatiens (jewelweed), Lonicera (honeysuckle), Monarda (bee balm), Prunella (selfheal), Solidago (goldenrod), Trifolium (clover), Vicia (vetches), and Viola (violet) as example food plants.

Recent reports have documented B. vagans visiting Symphyotricum spp. (aster) (4), Aster laevis (smooth blue aster) (1), Cirsium spp. (thistle) (4), Centaurea cyanus (cornflower) (1), Dipsacus fullonum (wild teasel) (1), Echinacea (coneflower) (1), Erigeron sp. (fleabane) (1), flowers in the Lamiaceae family (5), Gaillardia (blanket flowers) (1), Monarda punctata (horse mint) (6), Hypericum perforatum (St. John’s wort) (1), Iliuamna rivularis (Mountain hollyhock) (1), Centaurea sp. (knapweed) (2), Lavandula sp. (lavender) (14), Liatris sp. (blazing star) (1), Mimulus guttatus (monkey

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flower) (10), Convolvulaceae (morning glory) (1), Penstemon spp. (beardtongue) (2), Physalis philadelphica (tomatillo) (3), Salvia officinalis (sage) (2), Symphoricarpos sp. (snowberry) (1), Verbascum thapsus (common mullein) (1), Vicia spp. (vetch) (3), and Zinnia spp. (zinnia) (5) (Xerces et al. 2019).

Overwintering Sites: Very little is known about the hibernacula, or overwintering sites, utilized by B. vagans, although generally bumble bee queens are known to overwinter in soft, disturbed soil (Goulson 2010), or under leaf litter or other debris (Williams et al. 2014).

Threats:

A recent study in the Pacific Northwest found that 80% of the Bombus spp. included in the study will experience a loss in suitable habitat over the next 50 years (Koch et al. 2019). Threats for B. vagans populations include invasive and other problematic species, reduced genetic diversity and diseases, and climate change (Hatfield et al. 2015b). Bombus vagans’ food preference (e.g., flowers with long corollas) and seasonal activity (e.g., active later in the season) make this species vulnerable to invasive plants, which may displace natives, and may cause it to be more susceptible to decline than species that are active earlier in the season (Hatfield et al. 2015b). Long-tongued bees are often specialists on fewer flowers meaning they are more vulnerable to changes in the plant community (e.g., encroachment of invasives) and nectar and pollen resources can be more limiting later in the season. Koch et al. (2019) found that Bombus spp. that have a longer tongues may be less resilient to a loss in resources and less effective at foraging floral resources when compared to bees with a shorter tongue lengths.

Bumble bees, in general, are threatened by a number of factors including habitat loss, pesticide use, pathogens from managed pollinators, competition with non-native bees, and climate change (reviewed in Goulson 2010; Williams et al. 2009; Williams and Osborne 2009; Cameron et al. 2011b; Fürst et al. 2014; Hatfield et al. 2012). Reduced genetic diversity resulting from any of these threats can be particularly concerning for bumble bees, since their method of sex-determination can be disrupted by inbreeding and genetic diversity already tends to be low due to the colonial life cycle (i.e., even large numbers of bumble bees may represent only one or a few

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queens) (Goulson 2010; Hatfield et al. 2012; but see Cameron et al. 2010 and Lozier et al. 2011).

Over grazing by livestock can be particularly harmful to bumble bees (reviewed in Hatfield et al. 2012) by removing floral resources, especially during the mid-summer period when flowers may already be scarce. In addition, livestock may trample nesting and overwintering sites, or disrupt rodent populations, which can indirectly harm bumble bees. Indirect effects of logging (such as increased siltation in runoff) and recreation (such as off-road vehicle use) also have the potential to alter meadow ecosystems and disrupt B. vagans habitat.

Additional habitat alterations, such as conifer encroachment resulting from fire suppression (Panzer 2002; Schultz and Crone 1998; Roland and Matter 2007), fire, agricultural intensification (Williams 1986; Carvell et al. 2006; Diekotter et al. 2006; Fitzpatrick et al. 2007; Kosior et al. 2007; Goulson et al. 2008), urban development (Jha and Kremen 2012; Bhattacharya et al. 2003), and climate change (Memmott et al. 2007; Thomson 2010; Cameron et al. 2011b; Kerr et al. 2015) may threaten B. vagans. Climate change can result in changes in bumble bee life history, in community interactions and resources, and habitat structure that bumble bees rely on (Cameron et al. 2010; Hatfield et al. 2014; Koch et al. 2019).

Insecticides, which are designed to kill insects directly, and herbicides, which can remove floral resources, both pose serious threats to bumble bees. Of particular concern are neonicotinoids, a class of systemic insecticides whose toxins are extraordinarily persistent and are expressed in the nectar and pollen of plants (and therefore are actively collected by bumble bees), and exert both lethal and sublethal effects on bumble bees (Whitehorn et al. 2012, reviewed in Hopwood et al. 2016).

Bumble bees may be more vulnerable to extinction than other species due to their unique system of reproduction (haplodiploidy with single locus complementary sex determination) (Zayed and Packer 2005, reviewed in Zayed 2009).

In a rangewide study of eight bumble bee species, declining species were associated with increased levels of the fungal pathogen Nosema bombi relative to species that were found to be stable (Cameron et al. 2010). Bombus vagans was not included in this study, but multiple species showed

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elevated pathogen levels, and it is possible that B. vagans has been or could be similarly impacted. The hypothesis, developed by Dr. Robbin Thorp, that an exotic strain of N. bombi was introduced to North American bumble bees via the commercial bumble bee industry is still under investigation; however, recent evidence suggests that while this may be the case, the strain does not appear to be novel or exotic (Cameron et al. 2016). Pathogens and parasites from other sources, such as RNA viruses from honey bee colonies (Singh et al. 2010), also threaten wild bumble bees. As such, land managers should use caution when considering the placement of honey bee apiaries or hives in natural areas, including National Forests (Hatfield et al. 2016).

Conservation Considerations:

Research: More research is needed to assess basic life history and ecological questions, including nesting preferences, overwintering needs, and important host plants in Oregon and Washington.

Inventory: Historically records for B. vagans in Oregon and Washington were quite limited. Records from 1903-1986 documented this species from only Whitman, Wallowa, and Walla Walla Counties. Increased survey efforts in Washington and northeastern Oregon have led to more detections of this species in the Pacific Northwest. Records from 2008-2018 have confirmed this species’ occurrence in an additional 9 counties. In general, B. vagans would continue to benefit from targeted surveys or inclusion in more general Bombus spp. inventories to clarify its distribution throughout Pacific Northwest.

Management: Although specific management recommendations are limited for this species, implementing general conservation practices that support wild bee populations will benefit B. vagans. These include: 1) restoring, creating, and preserving natural high-quality habitats to include suitable forage, nesting and overwintering sites, 2) restricting pesticide use on or near suitable habitat, 3) minimizing exposure of wild bees to diseases transferred from managed bees, 4) avoiding honey bee introduction to high-quality native bee habitat (Hatfield et al. 2015b). Additionally, protect known and potential sites from practices such as livestock grazing and threats such as conifer encroachment that can interfere with the habitat requirements of

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this species (e.g., availability of nectar and pollen throughout the colony season and availability of underground nest sites and hibernacula).

Version 1: Prepared by: Katie Hietala-Henschell, Rich Hatfield, Sarina Jepsen, and Sarah Foltz JordanThe Xerces Society for Invertebrate ConservationDate: May 2019

Reviewed by: Candace FallonThe Xerces Society for Invertebrate ConservationDate: June 2019

Recommended citation:

Hietala-Henschell, K., R. Hatfield, S. Jepsen, and S. Foltz Jordan. 2019. Interagency Special Status/Sensitive Species Program (ISSSSP) Species Fact Sheet: Bombus vagans. USDA Forest Service Region 6 and USDI Bureau of Land Management Oregon State Office. 18 pp. Available at: https://www.fs.fed.us/r6/sfpnw/issssp/species-index/fauna-invertebrates.shtml       

ATTACHMENTS:

(1)References (2)List of pertinent or knowledgeable contacts (3)Map of known records in Oregon and Washington(4)Photographs and illustrations of this species(5)Survey protocol, including specifics for this species

ATTACHMENT 1: References

Bhattacharya, M., R.B. Primack, J. Gerwein. 2003. Are roads and railroads barriers to bumblebee movement in a temperate suburban conservation area? Biological conservation 109:37–45.

Burns, I. 2004. Social development and conflict in the North American bumblebee Bombus impatiens. University of Minnesota.

Cameron, S.A., J.D. Lozier, J.P. Strange, J.B. Koch, N. Cordes, L.F. Solter, and T.L. Griswold. 2010. Patterns of widespread decline in North American

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bumble bees. Proceedings of the National Academy of Sciences 108:662–667.

Cameron, S., S. Jepsen, E. Spevak, J. Strange, M. Vaughan, J. Engler, O. Byers (eds). 2011b. North American Bumble Bee Species Conservation Planning Workshop Final Report.

Cameron, S.A., H.C. Lim, J.D. Lozier, M.A. Duennes, and R. Thorp. 2016. Test of the invasive pathogen hypothesis of bumble bee decline in North America. Proceedings of the National Academy of Sciences of the United States of America.

Carvell, C., D.B. Roy, S.M. Smart, R.F. Pywell, C.D. Preston CD, and D. Goulson 2006. Declines in forage availability for bumblebees at a national scale. Biological conservation 132:481–489.

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December 2014. Document updated March 2, 2015. The Xerces Society for Invertebrate Conservation, Portland, OR.

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Yanega, D. 2013. The status of Cockerell’s Bumblebee, Bombus (Pyrobombus) cockerelli Franklin, 1913 (Hymenoptera: Apidae). Southwestern Entomologist. 3(38):517-522.

Zayed, A. 2009. Bee genetics and conservation. Apidologie 40:237–262.

Zayed A. and L. Packer. 2005. Complementary sex determination substantially increases extinction proneness of haplodiploid populations. Proceedings of the National Academy of Sciences of the United States of America 102:10742–10746.

Map references:

BISON [Biodiversity Information Serving Our Nation]. 2019. North American species occurrence data and maps. U.S. Department of the Interior. Accessed May 2019. Available at: https://bison.usgs.gov/#home

GBIF [Global Biodiversity Information Facility]. 2019. GBIF Occurrence Download. Online database. Accessed May 2019. Available at: https://www.gbif.org/search?q=BOMBUS%20VAGANS

Pacific Northwest Bumble Bee Atlas. 2019. The Xerces Society, Washington Department of Fish and Wildlife, Idaho Fish and Game, Oregon State University, The Oregon Bee Project, Oregon Department of Agriculture. Available: https://www.pnwbumblebeeatlas.org (data provided May 2019).

Bumble Bee Watch. 2019. The Xerces Society, Wildlife Preservation Canada, York University, The Montreal Insectarium, The London Natural History

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Museum, BeeSpotter. 2019. Online database. Available from http://www.bumblebeewatch.org (data provided May 2019).

ATTACHMENT 2: List of pertinent, knowledgeable contacts

Rich Hatfield, Xerces Society Sheila Colla, York University Leif Richardson, Stone Environmental and University of Vermont, USDA National Institute of Food and Agriculture Jonathan Koch, Utah State UniversityJames Strange, USDA ARS Logan Bee LabPaul Williams, Natural History Museum, London

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ATTACHMENT 3: Map of known Bombus vagans records in Oregon and Washington

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Known records of Bombus vagans in Oregon and Washington, relative to Forest Service and BLM land.

ATTACHMENT 4: Photographs and illustrations of this species

Illustration of adult female Bombus vagans. Identifying features include: face black, thorax mostly yellow, T1-T2 yellow, and T3-T5 black. Illustrations by Paul Williams and Elaine Evans, used with permission. Available at: www.bumblebeewatch.org

Photo of Bombus vagans. Image by Eric Lee Mader, The Xerces Society, used with permission. Image available at: https://www.bumblebeewatch.org/app/#/species/profile/vagans

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ATTACHMENT 5: Survey Protocol

Taxonomic group: Bombus

Where: Bumble bees inhabit a wide variety of natural, agricultural, urban, and rural habitats, although species richness tends to peak in flower-rich meadows of forests and subalpine zones (Goulson 2010). Bumble bees are generalist pollinators that visit a wide variety of plants. In California, Thorp et al. (1983) report that the top four plant families with the most records of bumble bee visitation are: 1) Compositae (=Asteraceae), 2) Leguminosae (=Fabaceae), 3) Labiatae (=Lamiaceae), and 4) Ericaceae. In general, bumble bee surveys should target flower-rich meadows with blooming plants that bumble bees are known to frequent. Note, however, that the floral associations of bumble bees are complicated by a variety of factors, including bumble bee species size, individual bee size, tongue length, specific floral preference, interspecific competition, pollen and nectar availability, flower species abundance within the landscape, and bumble bee species phenology (Thorp et al. 1983). For species-specific floral associations, see the section at the end of this protocol.

When: Adult bumble bees are best surveyed in mid- to late summer, during the peak flight period for worker bumble bees. Targeting the period when adult worker bumble bees are most abundant reduces the possibility of capturing queens (which would effectively eliminate an entire bumble bee colony), and increases one’s chances of encountering the most number of species, including rare species. Because phenology varies by species and elevation, survey timing for specific sites can be determined by reviewing the phenology of historic records for the target species at nearby sites coupled with an understanding of the peak availability of floral resources at specific sites. Sampling should occur on warm, calm, and sunny days, since bee foraging activity is reduced in cold, windy, and rainy conditions (LeBuhn et al. 2003).

How to Survey: Although pan-trapping is a method commonly recommended for sampling native bees, it is not recommended for bumble bees. Use of aerial sweep nets is a more appropriate method to collect bumble bees and other large-bodied native bees (Cane et al. 2000; Roulston et al. 2007) and will result in significantly less by-catch. Bumble bees nectaring at flowers

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typically remain in the same area for several minutes, and can be easily collected using an aerial sweep net. It is useful to use a net with a mesh that is light enough to see the specimen through the net. When stalking individuals at flowers, approach slowly from behind. When chasing, swing from behind and be prepared to pursue the insect. After capture, quickly flip the top of the net bag over to close the mouth and prevent the bumble bee from escaping. Once netted, most insects tend to fly upward, so hold the mouth of the net downward. To remove the specimen from the net by hand, insert a jar into the net in order to get the specimen into the jar without direct handling. Take care to not get stung; female bumble bees will sting when disturbed and can sting you through the netting material.

Some bumble bee species can be readily identified by macroscopic characters, so high quality photographs may provide sufficient evidence of species occurrences at a site, and those of lesser quality will at least be valuable in directing further study to an area. Use a camera with a good zoom or macro lens and focus on the aspects of the body that are the most critical to species determination (see note below). Multiple photos of different angles of the specimen will aid in identification. It is helpful to use a square-shaped jar when taking photos of a live specimen, as the square jars do not distort images to the degree that rounded jars do. In addition, the bumble bee in the jar can be placed on ice for approximately 5-10 minutes; this will reduce the bee’s activity level, which will facilitate obtaining a photograph of the appropriate characters.

Guidelines for Photo Vouchers

Photo documentation of species should include clear photos of the following characters:

A photo of the hind leg for Psithyrus/sex diagnosis A photo of the face including detail of the color patterns of the face, top of

the head, and ideally cheek length A clear photo showing the color pattern on the abdomen (including ALL

segments - 2 photos are acceptable) A clear photo showing the color pattern on the thorax, including color

below the bases of the wings (the sides of the thorax - again, 2 photos are acceptable, if needed)

If the species has a yellow face, and a single yellow stripe on the abdomen, include a photo of the ventral side of the abdomen

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Other bumble bee species have close look-alikes and can only be determined using morphological characteristics visible with a stereoscope or high quality magnifying lens (loupe). The surveyor should familiarize themselves with the target species, their own expertise and experience, and determine if photo documentation or physical specimens will be necessary to identify the species. Note that photographs (especially those of low quality) may lead to uncertain identifications, while a specimen provides a certain determination. Any questions about this should be directed to a bumble bee expert (see attachment 2). If collection of voucher specimens is necessary, the captured bumble bee should be placed into a jar with an ethanol-soaked tissue at the bottom to kill it. Alternatively, it can be collected in an empty jar, and then frozen within ~8 hours of collecting it. After 2-3 days in the freezer, the specimen can be removed and pinned. If specimens are intended for use in DNA analysis, they can be stored in 95% ethanol instead of freezing and pinning them. The Very Handy Manual (Droege et al. 2015) provides detailed instructions on collecting, preparing, and pinning bumble bees for long term preservation and/or deposition in formal collections.

Collection labels include the following information: country, state, county, site, detailed locality information (including geographical coordinates, elevation, mileage from named location), date, time of day, floral host, and collector (LeBuhn et al. 2003). Complete determination labels include the species name, caste (queen, female worker, or male), determiner name, and date determined.

While researchers are visiting sites and collecting specimens, detailed habitat data should also be acquired, including vegetation types, vegetation canopy cover, suspected or documented host plant species, landscape contours (including direction and angle of slopes), and degree of human impact. Photographs of habitat are also a good supplement to collected specimens and, if taken, should be cataloged and referred to on the insect labels.

Timed surveys within a measured area can provide a useful way to quantify survey effort. Ninety person minutes is a good recommended search time for a given area (e.g. two people for 45 minutes, or three people for 30 minutes) (Strange et al. 2013). Captured bumble bees can be:

1. Placed into a lethal killing jar for later identification (ensure the collection of only males and workers – do not collect queens).

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2. Placed into vials and placed on ice for later identification.3. Placed into vials, photo documented, or identified and released (this

method does NOT ensure that individuals are not being recaptured).

These timed surveys will provide information about the detection of a particular bumble bee species, or suite of species (species richness) at a site. However, since the reproductive unit for true bumble bees (not in the subgenus Psithyrus) is at the colony level and not the individual level, these surveys will not provide population or abundance estimates. To determine the population size at any site(s), genetic analysis would have to be conducted by a competent and properly equipped laboratory. These analyses can be expensive and time consuming; researchers are strongly encouraged to establish a partner lab and research scientist before collecting material for analysis.

Identification: To identify a bumble bee to species, it is first necessary to determine whether the bee is male or female. There are three castes of bumble bees: workers (female), queens (female) and drones (male). Queens and workers generally have similar color patterns, although queens are generally much larger. Males tend to have different color patterns than females and are more variable, which make field-based identifications more challenging. To differentiate males from females there are three main characters to look at: the antennae, abdomen, and rear legs. Males have thirteen antennal segments, whereas females have twelve antennal segments. Male bumble bees have 7 abdominal segments, while females have 6 abdominal segments – and the tip of the abdomen is more pointed than in males. Finally, most female bumble bees have pollen collecting baskets on their rear legs called corbicula (the exception are female cuckoo bumble bees in the subgenus Psithyrus that do not collect pollen), while male bumble bees have more rounded, thinner legs.

Once the surveyor has determined the sex of the bumble bee (and whether the bumble bee is in the subgenus Psithyrus), the observer will often use color patterns on the head, thorax and abdomen to determine the specific name. In addition to hair color patterns and hair length, other features such as cheek (malar space) length, corbicular fringe hair color, location of simple eyes (ocelli) relative to the top of the compound eyes, and male genitalia structure can be useful in identifying bumble bees.

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Williams et al. (2014) published Bumble Bees of North America, which has color patterns and keys to male and female bumble bees for the entirety of North America. A field guide to bumble bees (and key to female bumble bees) of the western United States is available by Koch et al. (2012). A key to male and female bumble bees of the western United States can be found in Stephen (1957) and a key to male and female bumble bees of California is provided in Thorp et al. (1983).

Species-Specific Survey Details:

Bombus vagans

Where: This species has historically been sparsely distributed throughout eastern Washington and northeastern Oregon, but recent observations submitted through community science applications like Bumble Bee Watch have greatly increased this bee’s known distribution. Additional surveys at historic and potential sites on National Forests and BLM districts where B. vagans is suspected or documented would help to further delineate this bee’s current distribution in the Pacific Northwest. In particular, B. vagans may be present in additional counties within Wallowa-Whitman National Forest and surveys could include suitable habitat in Baker and Union Counties. This species has also been documented on the Okanogan-Wenatchee National Forest; additional surveys in Okanogan County may result in additional records. Surveys near recent records from the Colville National Forest and adjacent areas, especially in Okanogan and Stevens Counties, are recommended. Additionally, due to the close proximity of records, surveys are recommended on the Umatilla National Forest in Union and Umatilla Counties, Oregon, and in Walla Walla and Whitman Counties, Washington.

Surveys on Spokane BLM District land, especially in Okanogan, Lincoln, and Douglas Counties in Washington and on Vale-OR BLM District Land in Baker County are also recommended.

Forests, wetlands, urban parks, and gardens can all provide appropriate habitat for B. vagans. This species is a generalist forager and has been reported to visit a variety of flowering plants within its range. The following food plants have been associated with B. vagans: Aralia hispida (bristly sarsaparilla), Chelone glabra (white turtlehead), Clinopodium vulgare (wild

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basil), Hydrophyllum virginianum (Virginia waterleaf), Pontederia cordata (pickerelweed) Penstemon (beardtongue), Asclepias (milkweed), Aster, Cirsium (thistle), Eupatorium (boneset), Spiraea (spirea), Chelone spp. (turtlehead), Impatiens (jewelweed), Lonicera (honeysuckle), Monarda (bee balm), Prunella (selfheal), Solidago (goldenrod), Trifolium (clover), Vicia (vetches), and Viola (violet) (Koch et al. 2012; Williams et al. 2014; Xerces Society et al. 2019).

Although suitable habitat with flowers in the genera and families noted above may be targeted for surveys, it is important to note that these floral associations do not necessarily represent B. vagans’ preference for these plants over other flowering plants, but rather may represent the abundance of these flowers in the landscape. Other plants (including those with inconspicuous or small flowers) are worth surveying and should not be ignored.

When: Surveys should target the peak flight period for female workers, which is from July through early September for B. vagans (Williams et al. 2014). However, the peak flight period at a specific site will vary by elevation and local climatic conditions. The colony life cycle for B. vagans can begin as early as late March and, in some cases, can last until early November. According to Williams et al. (2014), the flight period for B. vagans queens ranges from March through early October, peaking in late May and early June. The flight period for workers is from early April to mid-October with a peak in August; the male flight period is from May to early-November, with a peak in early September (Williams et al. 2014).

Identification: Bombus vagans can potentially be confused in the field with B. impatiens, B. bimaculatus, B. sandersoni, B. perplexus, B. rufocinctus, and B. griseocollis (Williams et al. 2014). Bombus flavifrons and B. rufocinctus in particular can be confused with B. vagans (Koch et al. 2012). The color patterns for these species can be similar, with T1-2 predominantly yellow. There are many color variations within each of these species. The key color pattern differences for these species are in the color of T3-T5. Bombus vagans typically has black on T3-T5, sometimes yellow, while T3-T5 of B. flavifrons and B. rufocinctus can have yellow or orange hairs (Koch et al. 2012). Additionally, B. vagans has a long head with a malar space (cheek) that is just longer than broad (medium-cheeked), while B. rufocinctus has a short head length with a malar space that is distinctly shorter than broad (Williams et al. 2014). It is important to note that these characters are

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somewhat relative and can be challenging, even for a trained eye. While the color patterns for these species can be diagnostic, color patterns vary significantly within species and it will be important to verify sightings using key morphological characters. Having comparative voucher specimens, or the opinion of a trained taxonomist, will be extremely valuable.

References (survey protocol only):

Cane, J.H., R.L. Minckley, and L.J. Kervin. 2000. Sampling bees (Hymenoptera: Apiformes) for pollinator community studies: pitfalls of pan-trapping. Journal of the Kansas Entomological Society 73:225–231.

Droege, S., J. Green, T. Zarrillo, and L. Sellers. 2015. The very handy manual: how to catch and identify bees and manage a collection. Available at: http://bio2.elmira.edu/fieldbio/beemanual.pdf

Goulson, D. 2010. Bumblebees: Behavior, Ecology, and Conservation. Oxford University Press. 317 pages.

Koch, J.B., J.P. Strange, and P.H. Williams. 2012. Bumble Bees of the Western United States. USDA Forest Service and the Pollinator Partnership. Available at: http://www.fs.fed.us/wildflowers/pollinators/documents/BumbleBeeGuide2012.pdf

LeBuhn, G., T. Griswold, R. Minckley, S. Droege, T. Roulston, J. Cane, F. Parker, S. Buchmann, V. Tepedino, N. Williams, C. Kremen, and O.J. Messinger. 2003. A standardized method of monitoring bee populations—the Bee Inventory (BI) plot. Available at: http://online.sfsu.edu/~beeplot/pdfs/Bee%20Plot%202003.pdf

Roulston, T.H., S.A. Smith, and A.L. Brewster. 2007. Short communication: a comparison of pan trap and intensive net sampling techniques for documenting a bee (Hymenoptera: Apiformes) fauna. Journal of the Kansas Entomological Society 80:179–181.

Stephen, W.P. 1957. Bumble bees of western America. Oregon State University. 161 pages.

Strange, J., W. Sheppard, and J. Koch. 2013. Monitoring Bumble Bee Pollinators in the Pacific Northwest. USDA – ARS Pollinating Insects Research

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Unit. Available from https://irma.nps.gov/rprs/FileManager/IarAttachment?id=211202&iarID=103061 (accessed February 23, 2017).

Thorp, R.W., D.S Horning, and L.L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera: Apidae). Bulletin of the California Insect Survey 23: viii.

Williams, P.H., R.W. Thorp, L.L. Richardson, and S. Colla. 2014. Guide to the Bumble Bees of North America. Princeton University Press.

Xerces Society, Wildlife Preservation Canada, York University, The Montreal Insectarium, The London Natural History Museum, BeeSpotter. 2019. Data accessed from Bumble Bee Watch, a collaborative website to track and conserve North America’s bumble bees. Available from http://www.bumblebeewatch.org/app/#/bees/lists (accessed April 16, 2019).

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