SPECIES FACT SHEETScientific Name: Bombus frigidus Smith, 1854Common Name(s): Frigid bumble beePhylum: ArthropodaClass: InsectaOrder: HymenopteraSuborder: ApocritaFamily: ApidaeConservation Status:

Global Status: G5 (last reviewed 13 September 2015)National Status (United States): N4? (14 June 2010)State Statuses: SNR (OR); S2? (WA)(NatureServe 2018)

Federal Status (United States): Not listed (USFWS 2019)IUCN Red List: Least Concern (IUCN 2014)

Taxonomic Note:

Some records from the southern Appalachians were previously treated as Bombus frigidus sandersoni; this subspecies is now recognized as a full species and these records are now considered Bombus sandersoni (Hatfield et al. 2014; 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 counties, and they have not been detected in Washington (Discover Life 2013).

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Bombus frigidus, a member of the Pyrobombus subgenus, is most easily distinguished in the field from other Bombus species based on hair coloration. The species most similar whose ranges overlap with B. frigidus in Washington or Oregon are B. kirbiellus, B. mixtus, and B. vagans (Williams et al. 2014). Identifying features for B. frigidus are noted in the detailed description below (descriptions compiled from Williams et al. 2014 and Koch et al. 2012).

Queens and Workers: Bombus frigidus queens and workers are similar in coloration. The queen is 17 to 19 mm in length, whereas the worker is 8 to 11 mm in length. Their hair is long. The hair of the face is usually black, but sometimes with intermixed yellow hairs. The hair on the top of the thorax is predominantly yellow with a black band between the wings (contrast with B. mixtus where front pale band is intermixed). The first two tergal (dorsal plate) segments on the abdomen are yellow. Tergal segment 3 is black (contrast B. kirbiellus). Tergal segments 4 and 5 have predominantly orange hairs, with hairs on T5 occasionally fading to yellow (contrast B. vagans). In addition to color patterns, there are morphological differences between these species. Bombus frigidus has a medium length cheek as long as broad (contrast B. kirbiellus). Bombus frigidus females have a rounded corner on the distal posterior corner of their midleg basitarsus.

Males: Male B. frigidus are similar in coloration to workers and queens. The male is 10 to 15 mm in length. The hair on the top of the thorax is predominantly yellow and most forms have a black band between the wings. The hair on T1-T2 is yellow, T3-T4 is black, and T6-T7 is predominantly orange. The eyes of male B. frigidus are similar to females in both size and shape. 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 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

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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. frigidus nesting habits is unavailable, but generally this species will nest above ground or occasionally underground (Williams et al. 2014). 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. frigidus 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. frigidus, are generalist foragers and have been reported visiting a wide variety of flowering plants. B. frigidus is a medium-tongued species and important food plants include plants in the genera Epilobium (willowherbs), Hedysarum (sweetvetch), Lupinus (lupine), Potentilla (cinquefoils), Salix (willow), Trifolium (clover), and Vaccinium (blueberry) (Williams et al. 2014).

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, 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. frigidus queens is from April through September, peaking in June. The flight period for workers is from late April to early September with a peak in July; the male flight period is from late May to early September, with a peak in late July (Williams et al. 2014).

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Range, Distribution, and Abundance:

Type Locality: The specific locality for B. frigidus is not described in detail. Vague habitat locality information includes Arctic America and Hudson’s Bay (Smith 1854).Range: Bombus frigidus has a wide distribution in North America and occurs in mountain meadow, boreal forest, tundra, and taiga regions throughout the Canadian eastern maritime west to Alaska, and south to Oregon and Colorado (Williams et al. 2014). In Washington, this species is known from Jefferson, Thurston, Whatcom, Yakima, Cowlitz, Kitsap, Okanogan, Skagit, and King Counties. In Oregon, it is known from Baker County.

Distribution: In Washington, this species is known from Hurricane Ridge, Olympic Mountains (Jefferson County); Tenino Prairie (Thurston County); Slate Peak, Birch Bay, Chuckanut Bay, and Bellingham (Whatcom County); Bird Creek Meadow, Mt. Adams (Yakima County); Kalama River (Cowlitz County); Illahee (Kitsap County); Loup Loup Ski Area and Silver Star Mountain (Okanogan County); Rainy Pass (Skagit County); and Stevens Pass Ski Area (King County). In Oregon, it is known from Anthony Lake, Blue Mountains (Baker County).

BLM/Forest Service Land:

Documented: Bombus frigidus has been documented on the Okanogan-Wenatchee National Forest from the Stevens Pass Ski Area (King County), Rainy Pass (Skagit County), Slate Peak (Whatcom County), and Loup Loup Ski Area and Silver Star Mountain (Okanogan County). It is also documented on the Wallowa-Whitman National Forest from Anthony Lake, Blue Mountains (Baker County).

Suspected: In Washington, this species is suspected on the Mount Baker-Snoqualmie National Forest due to nearby records in Thurston and Whatcom Counties; Gifford Pinchot National Forest due to nearby records in Thurston, Yakima, and Cowlitz Counties; and Olympic National Forest due to a nearby record in Kitsap County.

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This species is also suspected on BLM land that may have suitable habitat including the Spokane BLM District in Washington (Okanogan and Chelan Counties) and Vale (Baker County) and Prineville (Grant County) BLM Districts in Oregon due to proximity to documented sites.

Abundance: Reliable estimates for insect populations are difficult to obtain and precise abundance estimates for B. frigidus are unavailable. Many areas where this species was historically found have not been sampled recently (Hatfield et al. 2014). In high latitude boreal and arctic parts of its range B. frigidus appears to be common. Based on the best available data, relative abundance and persistence measures do not show cause for concern (Hatfield et al. 2014) however, this species is considered rare in the western US (Koch et al. 2012).

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. frigidus 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 overwintering sites for the queens. Habitat for this species includes high elevation and high latitude tundra/taiga, mountain meadows, and boreal forests (Williams et al. 2014; Hatfield et al. 2014).

Nest Sites: Reports of B. frigidus nests are primarily aboveground, and occasionally belowground (Williams et al. 2014). Male B. frigidus 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 is generally from April to September for B. frigidus. 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.

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Bombus frigidus, like other Bombus spp., is a generalist forager. Plant associations for this species include: Hyssopus (hyssop), Chamaenerion (fireweed), Draba surea (golden draba), Helianthella quinquenervis (five-nerve helianthella), Polemonium caeruleum (Jacob’s ladder) (Xerces Society et al. 2019), Chamerion (fireweed), Lupinus (lupine), Geranium (geranium), Symphoricarpos (snowberry), Trifolium (clover), and Achillea (yarrow) (Koch et al. 2012). Additionally, Williams et al. (2014) report plants in the genera Epilobium (willowherbs), Hedysarum (sweetvetch), Potentilla (cinquefoils), Salix (willow), and Vaccinium (blueberry) (Williams et al. 2014).

Overwintering Sites: Very little is known about the hibernacula, or overwintering sites, utilized by B. frigidus, 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:

This species is globally listed as secure (G5) but needs to be reviewed in Oregon (SNR) and is considered imperiled in Washington (S2?) (NatureServe 2018). The primary threat for B. frigidus populations is climate change due to this species’ reliance on high elevation and high latitude habitats (Hatfield et al. 2014). Climate change can result in changes in bumble bee life history, in community interactions and resources, and habitat structures that bumble bees rely on (Cameron et al. 2011a; Hatfield et al. 2014; Koch et al. 2019).

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. 2008; 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 queens) (Goulson 2010; Hatfield et al. 2012, but see Cameron et al. 2011a and Lozier et al. 2011).

Overgrazing 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

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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. frigidus 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. frigidus. High elevation habitat changes caused by human activities, geomorphological factors, and warming may contribute to B. frigidus declines and habitat loss. A recent study found that bumble bees found in high altitude environments have a higher risk of experiencing a loss in suitable habitat in the next 50 years and that 80% of the bumble bee species studied in the Pacific Northwest will experience habitat suitability loss (Koch et al. 2019). In response to changing climatic conditions, alpine tree lines can advance upslope, potentially altering previously open habitats and degrading areas previously used by bumble bees for nesting, overwintering, and forage (Kerr et al. 2015). Koch et al. (2019) found that changes in precipitation caused by climate change served as a significant predictor of bumble bee habitat suitability.

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

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relative to species that were found to be stable (Cameron et al. 2011a). Bombus frigidus was not included in this study, but multiple species showed elevated pathogen levels, and it is possible that B. frigidus 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 evaluate the status of this species throughout its range, especially in Washington and Oregon. Current understanding of B. frigidus distribution is limited and needs to be reevaluated, as large areas of its historic range have been under-surveyed (Hatfield et al. 2014). A better understanding of this species’ distribution is the first step to evaluating threats and potential declines in B. frigidus populations (Hatfield et al. 2014). More research is also needed to assess basic life history and ecological questions, including nesting preferences, overwintering needs, and important host plants in Washington and Oregon.

Inventory: Increased survey efforts in Washington and Oregon may lead to more detections of this species. In general, B. frigidus would 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. frigidus. 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, and 4) avoiding honey bee introduction to high-quality native bee habitat (Hatfield et al. 2014). Additionally, protect known and potential sites from practices such as livestock grazing and threats such as conifer encroachment that can interfere with the habitat

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requirements of 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 frigidus. 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. 2011a. 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.

Diekötter, T., K. Walther-Hellwig, M. Conradi, M. Suter, and R. Frankl. 2006. Effects of landscape elements on the distribution of the rare bumblebee species Bombus muscorum in an agricultural landscape. Arthropod Diversity and Conservation: 43–54.

Fitzpatrick, Ú., T.E. Murray, R.J. Paxton, J. Breen, D. Cotton, V. Santorum, and M.J.F. Brown. 2007. Rarity and decline in bumblebees – A test of causes and correlates in the Irish fauna. Biological conservation 136:185–194.

Fürst, M.A., D.P. McMahon, J.L. Osborne, R.J. Paxton, and M.J.F. Brown. 2014. Disease associations between honeybees and bumblebees as a threat to wild pollinators. Nature 506:364–366.

Goulson, D. 2010. Bumblebees: behaviour, ecology, and conservation. Oxford University Press.

Goulson, D., G.C. Lye, and B. Darvill B. 2008. Decline and conservation of bumble bees. Annual review of entomology 53:191–208.

Hatfield, R., S. Jepsen, E. Mader, S.H. Black, and M. Shepherd. 2012. Conserving Bumble Bees. Guide-lines for Creating and Managing Habitat for America’s Declining Pollinators. Available from http://www.xerces.org/wp-content/uploads/2012/06/conserving_bb.pdf (accessed August 28, 2014).

Hatfield, R., S. Jepsen, R. Thorp, L. Richardson, and S. Colla. 2014. Bombus frigidus. The IUCN Red List of Threatened Species 2014:

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e.T44937790A69002715. http://dx.doi.org/10.2305/IUCN.UK.2014-3.RLTS.T44937790A69002715.en

Hatfield, R.G., S.R. Colla, S. Jepsen, L.L. Richardson, R.W. Thorp, and S. Foltz-Jordan. 2015. IUCN Assessments for North American Bombus spp. for the North American IUCN Bumble Bee Specialist Group. Assessment completed December 2014. Document updated March 2, 2015. The Xerces Society for Invertebrate Conservation, Portland, OR.

Hatfield, R.G., S. Jepsen, M. Vaughan, S.H. Black, and E. Mader. 2016. An overview of the potential impacts of honey bees to native bees, plant communities, and ecosystems in wild landscapes: Recommendations for land managers. Available from http://www.xerces.org/wp-content/uploads/2016/09/Xerces_policy_statement_HB_Final.pdf.

Hopwood, J., A. Code, M. Vaughan, D. Biddinger, M. Shepherd, S.H. Black, E. Mader, and C. Mazzacano. 2016. How Neonicotinoids Can Kill Bees. 2016-022. The Xerces Society. Available from http://www.xerces.org/wp-content/uploads/2016/10/HowNeonicsCanKillBees_XercesSociety_Nov2016.pdf .

[ITIS] Integrated Taxonomic Information System. 2019. ITIS Report: Bombus frigidus Smith, 1854. TSN 714806. Accessed: 15 April 2019. Available at: http://www.itis.gov

Jha, S. and C. Kremen. 2013. Resource diversity and landscape-level homogeneity drive native bee foraging. Proceedings of the National Academy of Sciences 110:555–558.

Kerr, J.T., A. Pindar, P. Galpern, L. Packer, S.G. Potts, S.M. Roberts, P. Rasmont, O. Schweiger, S.R. Colla, L.L. Richardson, D.L. Wagner, L.F. Gall, D.S. Sikes, and A. Pantoja. 2015. Climate change impacts on bumblebees converge across continents. Science 349:177–180.

Koch, J.B., C. Looney, B. Hopkins, E.M. Lichtenberg, W.S. Sheppard, and J.P. Strange. 2019. Projected climate change will reduce habitat suitability for bumble bees in the Pacific Northwest. bioRXiv. DOI: https://doi.org/10.1101/610071

Koch, J., J. Strange, and P. Williams. 2012. Bumble bees of the Western United States. A product of the U.S. Forest Service and the Pollinator

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Partnership with funding from the National Fish and Wildlife Foundation. 144 pp. Available at: https://www.fs.fed.us/wildflowers/pollinators/documents/BumbleBeeGuideWestern2012.pdf

Kosior, A., W. Celary, P. Olejniczak, J. Fijal, W. Krol, W. Solarz, and P. Plonka. 2007. The decline of the bumble bees and cuckoo bees (Hymenoptera: Apidae: Bombini) of Western and Central Europe. Oryx: the journal of the Fauna Preservation Society 41:79.

Lozier, J.D., J.P. Strange, I.J. Stewart, and S.A. Cameron. 2011. Patterns of range-wide genetic variation in six North American bumble bee (Apidae: Bombus) species. Molecular ecology.

Memmott, J., P.G. Craze, N.M. Waser, and M.V. Price. 2007. Global warming and the disruption of plant--pollinator interactions. Ecology letters 10:710–717.

Michener, C.D. 2007. The bees of the world. JHU Press.

NatureServe. 2018. Bombus frigidus Smith, 1854. Version 7.1 (2 February 2009) Data last updated March 2018. Accessed 25 April 2019. Available at: http://explorer.natureserve.org/index.htm

Panzer, R. 2002. Compatibility of prescribed burning with the conservation of insects in small, isolated prairie reserves. Conservation biology: the journal of the Society for Conservation Biology 16:1296–1307.

Roland, J. and S.F. Matter. 2007. Encroaching forests decouple alpine butterfly population dynamics. Proceedings of the National Academy of Sciences 104:13702–13704.

Schultz, C.B. and E.E. Crone. 1998. Burning Prairie to Restore Butterfly Habitat: A Modeling Approach to Management Tradeoffs for the Fender’s Blue. Restoration Ecology 6.

Singh, R., A.L. Levitt, E.G. Rajotte, E.C. Holmes, N. Ostiguy, D. vanEngelsdorp, W.I. Lipkin, C.W. dePamphilis, A.L. Toth, and D.L. Cox-Foster. 2010. RNA Viruses in Hymenopteran Pollinators: Evidence of Inter-Taxa Virus Transmission via Pollen and Potential Impact on Non-Apis Hymenopteran Species. PLoS ONE 5(12): e14357. doi:10.1371/journal.pone.0014357.

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Smith, F. 1854. Catalogue of hymenopterous insects in the collection of the British Museum. Part II. Apidae. London, UK.

Thomson, J.D. 2010. Flowering phenology, fruiting success and progressive deterioration of pollination in an early-flowering geophyte. Philosophical transactions of the Royal Society of London. Series B, Biological sciences 365:3187–3199.

Thorp, R.W., D.S. Horning, and L.L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera, Apidae). University of California Press.

[USFWS] United States Fish and Wildlife Service. 2019. Environmental Conservation Online System (ECOS). Online database. Available at: https://ecos.fws.gov/ecp0/reports/ad-hoc-species-report-input

Whitehorn, P.R., S. O’Connor, F.L. Wackers, and D. Goulson. 2012. Neonicotinoid pesticide reduces bumble bee colony growth and queen production. Science 10.1126/science.1215025.

Williams, P.H. 1986. Environmental change and the distributions of British bumble bees (Bombus Latr.). Bee World 67:50–61.

Williams, P., S. Colla, and Z. Xie. 2008. Bumblebee Vulnerability: Common Correlates of Winners and Losers across Three Continents. Conservation biology: the journal of the Society for Conservation Biology 23:931–940.

Williams, P.H., and J.L. Osborne. 2009. Bumblebee vulnerability and conservation world-wide. Apidologie 40:367–387.

Williams, P.H., R.W. Thorp, L.L. Richardson, and S.R. Colla. 2014. Bumble Bees of North America: An Identification Guide: An Identification Guide. 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).

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

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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/en/search?q=bombus%20frigidus

[NMNH] National Museum of Natural History, Smithsonian Institution. 2019. Department of Zoology Collections. Online database. Accessed May 2019. Available at: https://collections.nmnh.si.edu/search/iz/

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 frigidus records in Oregon and Washington

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

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ATTACHMENT 4: Illustrations and photographs of this species

Illustration of Bombus frigidus, black between the wing bands and face, abdominal segment T3 black and T4-T5 orange. Illustrations by Paul Williams and Elaine Evans, used with permission. Available at: www.bumblebeewatch.org

Photo of Bombus frigidus from Cochrane District, ON, Canada. Image by © Isabel, used under a Creative Commons agreement (CC BY-NC 4.0). Image available at: https://www.inaturalist.org/photos/23377324

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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 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

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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

Other bumble bee species have close look-alikes and can only be determined using morphological characteristics visible with a stereoscope or high quality

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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).

2. Placed into vials and placed on ice for later identification.

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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.

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

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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 frigidus

Where: Mountain meadows and open boreal forests are appropriate habitat for this species. This species has historically been sparsely distributed throughout Washington and is known from only one site in Oregon. Additional surveys at historic and potential sites on National Forests and BLM districts where B. frigidus is suspected or documented are needed to identify this bee’s current distribution in the state. Due to the close proximity of records, B. frigidus may be present in the Mount Baker-Snoqualmie, Gifford Pinchot, and Olympic National Forests and surveys could include suitable habitat at high elevations sites. Additional surveys could occur on Spokane, Vale-OR, and Prineville BLM District Land where suitable habitat exists, due to the close proximity of records.

Bombus frigidus 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. frigidus: Hyssopus (hyssop), Chamaenerion (fireweed), Draba surea (golden draba), Helianthella quinquenervis (five-nerve helianthella), Polemonium caeruleum (Jacob’s ladder) (Xerces Society et al. 2019), Chamerion (fireweed), Lupinus (lupine), Geranium (geranium), Symphoricarpos (snowberry), Trifolium (clover), and Achillea (yarrow) (Koch et al. 2012). Additionally, Williams et al. (2014) report plants in the genera Epilobium (willowherbs), Hedysarum (sweetvetch), Potentilla (cinquefoils), Salix (willow), and Vaccinium (blueberry).

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. frigidus’ 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

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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 late-May through September for B. frigidus (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. frigidus can begin as early as April. According to Williams et al. (2014), the flight period for B. frigidus queens ranges from April to September, peaking in June. The flight period for workers and males is from late May to early September; worker abundance peaks in July, and male abundance peaks in July (Williams et al. 2014).

Identification: Bombus frigidus can potentially be confused in the field with B. kirbiellus, B. mixtus, or B. vagans (Williams et al. 2014). Bombus frigidus in particular can be confused with B. kirbiellus (Koch et al. 2012). The color patterns for these species are very similar with, T1-2 predominantly yellow and T4-5 predominantly orange. The key color pattern differences for these two species are in the color of T3. Bombus frigidus has black on T3, while B. kirbiellus has yellow T3, at least apicolaterally (Koch et al. 2012). Additionally, B. frigidus has a medium head length with a malar space that is as long as broad, while B. kirbiellus has a long head with a malar space (cheek) that is much longer than broad (long-cheeked) (Williams et al. 2014).

It is important to note that these characters are 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

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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 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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