SPECIES FACT SHEETCommon Name: Suckley Cuckoo Bumble BeeScientific Name: Bombus suckleyi Greene, 1860Phylum: ArthropodaSubphylum: MandibulataClass: InsectaOrder: HymenopteraFamily: ApidaeTribe: BombiniGenus: BombusSubgenus: Psithyrus Lepeletier(ITIS 2017)

Conservation Status: Global Status: G1G3 (2015)  National Statuses: United States (NU, 2010), Canada (NU, 2010)State or Province Statuses: United States: Alaska (SNR), California (S1), Montana (SNR), Nebraska (SNR), New York (SNA), Oregon (S1?), Washington (S1?)Canada: Alberta (SNR), British Columbia (SNR), Manitoba (NSR), Saskatchewan (SNR), Yukon Territory (SU), (NatureServe 2017). Oregon ranks from ORBIC, 2016; Washington ranks from WNHP 2016.

IUCN Red List: CR (2013)

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 where they are largely confined to Klamath, Jackson, Josephine, and Wallowa counties; they have not been detected in Washington (Discover Life 2013).

Bombus suckleyi is most easily distinguished in the field from other Bombus species based on hair coloration and physical characteristics. The species most similar whose range overlaps with B. suckleyi in Washington and Oregon are B. insularis and B. flavidus. The differences between these

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species and B. suckleyi are noted in the detailed description below (descriptions compiled in part from Williams et al. 2014).

Females: Bombus suckleyi females are 18 to 23 mm in length. Cuckoo bumble bees, members of the subgenus Psithyrus (including B. suckleyi), do not have a corbicula (pollen carrying basket on their hind leg), unlike the true bumble bees (pollen collecting, social species). Instead, their hind leg tibia is convex and densely covered in hairs. B. suckleyi’s hair is short and even. The hair of the head (including the vertex – top of the head) is black (contrast B. insularis – yellow face and vertex, and B. flavidus – yellow vertex). The hair of the thorax (including below the wings) is mostly yellow, with a black spot or band between the wings, sometimes with a black triangular notch behind, and between the wings. The first two tergal (T-dorsal plate) segments on the abdomen are black (contrast most B. flavidus), usually with at least some yellow (laterally and posteriorly) on T3 – no yellow centrally. T4 has predominantly yellow hairs, with a patch of black centrally and anteriorly (contrast B. flavidus). T5 is usually black, but can have yellow laterally; T6 is black.

Males: The male is 13 to 16 mm in length. The color patterns for males of this species are extremely variable. The only consistent features are yellow on all of T1 and T4 (contrast B. insularis), with some (or all) yellow on T2, T3, T5 and T6. T7 is black (contrast B. flavidus).

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.

Bombus suckleyi, and other species in the subgenus Psithyrus, are unique in that they are dependent on another Bombus spp. to serve as a host. Because they have no corbicula, they have an obligate dependency on social bumble bees (Goulson 2010) to collect pollen on which to rear their young. As such, B. suckleyi are a cuckoo species that are nest parasites of other species of bumble bees and are not primitively eusocial themselves – there is no division of labor within the species; all members of the species have equal status, and are reproductive.

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Cuckoo bumble bees typically emerge from their hibernacula later in the spring than other bumble bee species. This ensures that adequate hosts will have an established nest before the female emerges. Once the female Psithyrus does emerge, she forages for herself and begins searching for occupied nests. Once she finds a suitable host (some cuckoo bumble bees have a narrow range of possible host species) she enters the nest, kills or subdues the queen of that colony, and forcibly (using pheromones and/or physical attacks) "enslaves" the workers of that colony. Then she lays her own eggs and forces the workers of the native colony to feed her and her developing young. Since all of the resulting cuckoo bee offspring are reproductive (not workers), they leave the colony to mate, and the mated females seek out a place to overwinter, then repeat the cycle the following spring/early summer (Goulson 2010).

Cuckoo bumble bees often attack a broad range of host species, but some species specialize in attacking the members of just one species or subgenus. Bombus suckleyi has been recorded in nests of bumble bees in six different subgenera, but the most common associations were with the subgenera Pyrobombus and Bombus, and the only nests in which B. suckleyi adults were produced were those of B. occidentalis (reviewed in Thorp et al. 1983). As such, B. suckleyi has been documented breeding as a parasite of colonies of Bombus occidentalis, and has been recorded as present in the colonies of B. terricola, B. rufocinctus, B. fervidus, B. nevadensis, and B. appositus (Williams et al. 2014).

Bumble bees, including Bombus suckleyi, are generalist foragers and have been reported visiting a wide variety of flowering plants. While B. suckleyi females do not collect pollen to return to the nest, both males and females of this species forage for pollen and nectar from flowers for their own nutritional and energetic needs. The adult food plants of this species include "Aster", Chrysothamnus sp., Cirsium sp., and Solidago sp. (Williams et al. 2014). There are also several records of this species visiting Centaurea repens (Richardson 2017). Males of this species also patrol repeated circuits in search of mates (Thorp et al. 1983).

According to Williams et al. (2014), the flight period for B. suckleyi females is from April through October, peaking in June. The flight period for males is from May through early October, with a peak in late August (Williams et al. 2014).

Range, Distribution, and Abundance:Bombus suckleyi historically occurred throughout much of the western United States, though largely confined to mountainous regions. It is also present east through the Canadian Great Plains. This species is known from northern California, Oregon, Washington, Idaho, Colorado, Montana, North Dakota, South Dakota, British Columbia, Alaska, the Yukon and Northwest

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Territories, Alberta, Saskatchewan, and Manitoba. There is also a disjunct population in eastern North America with a few records in New York, Ontario, Quebec, Nova Scotia, and Newfoundland and Labrador. (Williams et al. 2014).

A recent analysis by Hatfield et al. (2014) indicates that this species has undergone significant declines throughout much of its range; it was listed as Critically Endangered on the IUCN Red List (Hatfield et al. 2015). Notably, this species' decline mirrors that of B. occidentalis, its only known host. 

In Oregon, this species has been historically observed along the Cascade Mountains, with a few observations in the coast range, and a handful of observations in the northeastern portion of the state (Richardson 2017). The two most recent records from the state are from 1994 in Lane County (Richardson 2017) and 2015 in Jackson County (Xerces Society et al. 2017). The records in Washington are scattered in the Cascade Mountains, the Olympic Mountains, in the Puget Trough, and along the eastern border, near Idaho. The most recent record in the state is from 1998 in Walla Walla County (Richardson 2017).

BLM/Forest Service Land: In Washington, this species has been Documented on the Mt Baker-Snoqualmie National Forest. It is Suspected on the Colville, Okanogan-Wenatchee, Gifford Pinchot and Umatilla National Forests and Spokane District BLM lands due to proximity to known records (see Attachment 3). In Oregon, this species has been Documented on the Deschutes, Fremont-Winema, Mt. Hood, Rogue River-Siskiyou, Wallowa-Whitman and Willamette National Forests, as well as the BLM Northwest Oregon District lands. It is Suspected on the BLM Vale District due to proximity to known records (see Attachment 3). A recent compilation of records for this fact sheet shows that this species has records in Franklin, Jefferson, King, Kitsap, Pend Oreille, Pierce, Spokane, Stevens, Thurston, Walla Walla, Whitman, and Yakima Counties in Washington. In Oregon, B. suckleyi has records in Baker, Benton, Clatsop, Deschutes, Hood River, Jackson, Klamath, Lane, Linn, Union, and Wallowa Counties.

Many of the records are older, and it is unknown if the species is still present in many of those localities.

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). Bombus suckleyi has three basic habitat requirements: suitable occupied nesting sites for its host (e.g. Bombus occidentalis), nectar and pollen from floral resources available throughout the duration of the colony period (spring, summer and fall), and

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suitable overwintering sites for the queens.

Nest Sites: B. suckleyi has been detected in the nests of several species of bumble bees, but it has only ever been observed reproducing in nests of B. occidentalis (Thorp et al. 1983). B. occidentalis nests are primarily in underground cavities such as old squirrel or other animal nests and in open west-southwest slopes bordered by trees, although a few nests have been reported from above-ground locations such as in logs among railroad ties (Hobbs 1968, MacFarlane et al. 1994, Plath 1922, Thorp et al. 1983). Availability of nest sites for B. occidentalis may depend on rodent abundance (Evans et al. 2008). Nest tunnels have been reported to be up to 2.1 m long for this species and the nests may be lined with grass or bird feathers (MacFarlane et al. 1994). Note: the presence of suitable nesting sites for B. occidentalis is not sufficient for the survival of this species, it is also dependent on extant populations of that species (see Life History above).

Floral Resources: Bumble bees require plants that bloom and provide adequate nectar and pollen throughout the colony’s life cycle, which is from mid-April to October for B. suckleyi (although the actual dates likely vary by elevation). In order for B. suckleyi to survive, there must also be early season resources for its host, B. occidentalis. There are records of B. occidentalis from early February to late November. 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 suckleyi is a generalist forager and has been reported to visit a wide variety of flowering plants. The known plant associations for this species in Oregon and Washington are scarce, but generally this species is associated with plants in the following genera: “Aster”, Chrysothamnus, Cirsium, and Solidago, and Centaurea (Williams et al. 2014, Richardson 2017). Plant genera that are associated with B. occidentalis – its known host, and a prerequisite for the survival of B. suckleyi – in Oregon and Washington include: Trifolium (20 observations), Cirsium (12), Rubus (7), Solidago (6), Epilobium (5), Spiraea (5), Tilia (5), Cicuta (4), Heracleum (3), and Plantago (3) (Richardson 2017). Note that these floral associations do not necessarily represent B. occidentalis’ or B. suckleyi’s preference for these plants over other flowering plants, but rather may represent the abundance of these flowers in the landscape.

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

Threats:The recent steep declines in relative abundance exhibited by this cuckoo bee are probably due to indirect threats (e.g., disease, decline in habitat) resulting in loss of suitable hosts (Hatfield et al. 2015, Williams et al. 2014). This species is an obligate nest parasite of other bumble bees. The decline of its documented host B. occidentalis (Cameron et al. 2011a) is likely driving the decline of this species. Additional direct threats that may be impacting this species include pesticide use, habitat loss, pathogens from managed pollinators, competition with non-native bees, and climate change (reviewed in Goulson 2010, Williams et al. 2009, Williams and Osborne 2009, Fürst et al. 2014, Cameron et al. 2011b, 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 (Goulson 2010, Hatfield et al. 2012).

Since B. suckleyi is so closely tied to the success of its host, any threats that will potentially harm B. occidentalis also have the potential to imperil B. suckleyi. The primary threats to B. occidentalis at the sites where it currently exists in Oregon and Washington include: pathogens from commercial bumble bees and other sources, impacts from reduced genetic diversity, and habitat alterations including conifer encroachment (resulting from fire suppression), grazing, and logging. Other threats include pesticide use, fire, agricultural intensification, urban development and climate change. These threats are reviewed below.

In a rangewide study of eight bumble bee species, B. occidentalis and other 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. 2011a). Note that Cordes et al. (2012) found B. suckleyi also exhibited high prevalence of the microsporidium Nosema bombi (25%), although the sample size was low (four individuals). Recent evidence supports the hypothesis that commercial bumble bees are responsible for the distribution of this pathogen throughout North America (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). Modifications to bumble bee habitat from over grazing by livestock can be

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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. occidentalis and B. suckleyi habitat.

Additional habitat alterations, such as conifer encroachment resulting from fire suppression (Panzer 2002, Schultz & Crone 1998, Roland & Matter 2007), fire, agricultural intensification (Williams 1986, Carvell et al. 2006, Diekotter et al. 2006, Fitzpatrick et al. 2007, Kosior et al. 2007, and Goulson et al. 2008), urban development (Jha & Kremen 2012; Bhattacharya et al. 2003), and climate change (Memmott et al. 2007, Thomson 2010, Cameron et al. 2011b, Kerr et al. 2016) may threaten B. occidentalis and B. suckleyi.

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. 2017). These chemicals pose direct and indirect threats to B. occidentalis and B. suckleyi.

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 & Packer 2005, reviewed in Zayed 2009).

Conservation Considerations:Research: While this species has only been documented as reproducing in nests of B. occidentalis it has been observed in the nests of several other species. More research to determine if B. suckleyi could use other species as a successful host would help to better understand this species’ ecology. Additional life history information would also help to better understand this species’ biological needs. This includes important host plants, location and details of overwintering sites, and specific habitat associations.

Inventory: Records of this species in Oregon and Washington have been quite rare in recent collections. However, a sighting near Ashland, OR, in Jackson County (The Xerces Society et al. 2017) is the first observation since 1998. Survey effort east of the Cascade Crest has generally been quite low, and this

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species would benefit from targeted, or more general Bombus spp., surveys to better understand its distribution throughout both states.

Management: 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 this species and its host (availability of nectar and pollen throughout the colony season and availability of underground nest sites and hibernacula).

Prepared by: Rich Hatfield, Sarina Jepsen and Sarah Foltz Jordan, Xerces Society for Invertebrate ConservationDate: February 2017Reviewed by: Candace Fallon, Xerces Society for Invertebrate Conservation Date: March 2017ATTACHMENTS:

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

ATTACHMENT 1: References

Bhattacharya M, Primack RB, Gerwein J. 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 SA, Lozier JD, Strange JP, Koch JB, Cordes N, Solter LF, Griswold TL. 2011a. Patterns of widespread decline in North American bumble bees. Proceedings of the National Academy of Sciences 108:662–667.

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

Cameron SA, Lim HC, Lozier JD, Duennes MA, Thorp R. 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, Roy DB, Smart SM, Pywell RF, Preston CD, Goulson D. 2006. Declines in forage availability for bumblebees at a national scale. Biological conservation 132:481–489.

Cordes N. 2010. The role of pathogens in the decline of North American bumble bees with a focus on the microsporidium Nosema bombi. University of Illinois at Urbana-Champaign.

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Discover Life. 2013. Xylocopa page. Available at: http://www.discoverlife.org/20/q. Accessed 13 May 2013.

Diekötter T, Walther-Hellwig K, Conradi M, Suter M, Frankl R. 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.

Evans, E., R. W. Thorp, S. Jepsen, and S. H. Black. 2008. Status review of three formerly common species of bumble bee in the Subgenus Bombus. Available at http://www.xerces.org/wp-content/uploads/2009/03/xerces_2008_bombus_status_review.pdf.

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

Fürst MA, McMahon DP, Osborne JL, Paxton RJ, Brown MJF. 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, Lye GC, Darvill B. 2008. Decline and conservation of bumble bees. Annual review of entomology 53:191–208.

Greene, J.W. 1860. XXI. Review of the American Bombidae, together with a description of several species heretofore undescribed, being a synopsis of this family of Hymenopterous insects thus far known to inhabit North America. Annals of the Lyceum of Natural History of New York 7: 168-176

Hatfield RG, Colla SR, Jepsen S, Richardson LL, Thorp RW, Foltz-Jordan S. 2014a. IUCN Assessments for North American Bombus spp. for the North American IUCN Bumble Bee Specialist Group. The Xerces Society for Invertebrate Conservation, Portland, OR.

Hatfield, R., Jepsen, S., Thorp, R., Richardson, L. & Colla, S. 2015. Bombus suckleyi. The IUCN Red List of Threatened Species 2015: e.T44937699A46440241. http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T44937699A46440241.en. Downloaded on 01 March 2017.

Hatfield R, Jepsen S, Mader E, Black SH, Shepherd M. 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 RG, Jensen S, Vaughan M, Black S, Mader E. 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.

Hobbs GA. 1968. Ecology of species of Bombus Latr. (Hymenoptera: Apidae) in southern Alberta. VII. Subgenus Bombus. Can. Entomol 100:1156–1164.

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Hopwood J, Code A, Vaughan M, Biddinger D, Shepherd M, Black SH, Mader E, Mazzacano C. 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.

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

Kerr JT et al. 2015. Climate change impacts on bumblebees converge across continents. Science 349:177–180.

Kosior A, Celary W, Olejniczak P, Fijal J, Krol W, Solarz W, Plonka P. 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.

Macfarlane R. P., K. D. Patten, L. A. Royce, B. K. W. Wyatt, and D. F. Mayer. 1994. Management potential of sixteen North American bumble bee species. Melanderia 50:1-12.

Memmott J, Craze PG, Waser NM, Price MV. 2007. Global warming and the disruption of plant--pollinator interactions. Ecology letters 10:710–717.

Michener CD. 2007. The bees of the world. JHU Press. [ORBIC] Oregon Biodiversity Information Center. 2016. Oregon Rare,

Threatened, and Endangered Species List; updated August 2016. Portland, Oregon. Available at http://inr.oregonstate.edu/orbic/rare-species/rare-species-oregon-publications (accessed March 22, 2016].

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.

Plath OE. 1922. Notes on Psithyrus, with records of two new American hosts. The Biological bulletin 43:23–44.

Richardson L. 2017. Data Contributors. Available from http://www.leifrichardson.org/bbna.html (accessed February 22, 2017).

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

Schultz CB, Crone EE. 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.

Thomson JD. 2010. Flowering phenology, fruiting success and progressive deterioration of pollination in an early-flowering geophyte. Philosophical

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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). Bulletin of the California Insect Survey 23: viii.

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

Williams P, Colla S, Xie Z. 2009. 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 PH. 1986. Environmental change and the distributions of British bumble bees (Bombus Latr.). Bee World 67:50–61.

Williams PH, Osborne JL. 2009. Bumblebee vulnerability and conservation world-wide. Apidologie 40:367–387.

Williams PH, Thorp RW, Richardson LL, Colla SR. 2014. Bumble Bees of North America: An Identification Guide: An Identification Guide. Princeton University Press.

[WNHP] Washington Natural Heritage Program. 2016. Washington Natural Heritage Program List of Animal Species with Ranks, May 2016. Olympia, Washington. Available at: http://file.dnr.wa.gov/publications/amp_nh_animals_ranks.pdf (accessed March 22, 2017).

The Xerces Society, Wildlife Preservation Canada, York University, The Montreal Insectarium, The London Natural History Museum, BeeSpotter. 2017. 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 February 22, 2017).

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

ATTACHMENT 2: List of pertinent or knowledgeable contacts

Robbin Thorp, University of California, DavisJames Strange, USDA ARS Logan Bee LabTerry Griswold, USDA ARS Logan Bee LabPaul Williams, Natural History Museum, LondonMichael Otterstatter, Health CanadaCory Sheffield, Royal Saskatchewan MuseumJames Thomson, University of TorontoSarina Jepsen, Xerces Society

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Rich Hatfield, Xerces Society Jeff Lozier, University of Alabama

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ATTACHMENT 3: Maps of species distribution and proximity of records to Suspected National Forests and BLM Districts.

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ATTACHMENT 4: Illustration and photographs of species

B. suckleyi (female), nominate color form. Although several color patterns for females of this species have been described (see Williams et al. 2014), the color form illustrated above is representative of female B. suckleyi that occur in Oregon and Washington. Illustration by Elaine Evans and Rich Hatfield, the Xerces Society. Used with permission.

Bombus suckleyi photos: adult male left – dorsal view; adult female right – side view. Photo on right by www.discoverlife.org. Photo on left by Hadel Go/www.discoverlife.org. Photos used with permission.

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ATTACHMENT 5: Bombus survey protocol, including specifics for this species

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 is light enough to see the specimen through the net. When stalking individuals at flowers,

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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.

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 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

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bottom to kill it. Or, it can be collected in an empty jar, 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 to be used for 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 – avoid the collection of queens or female cuckoo bumble bees).

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.

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Identification: To identify a bumble bee to species, it is first necessary to determine whether the bee is male or female – and also whether it is a true bumble bee, or a cuckoo bumble bee (in the subgenus Psithyrus). For true bumble bees 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 of all bumble bees tend to have different color patterns than females and are also 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 length (malar space), 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 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 suckleyi

Where:This species has historically been sparsely distributed throughout much of Oregon and Washington. There has only been one observation of this species in Oregon and Washington since 2000 (Richardson 2017; The Xerces Society et al. 2017). This species also has an obligate dependency on social bumble bees, and to date has only been documented reproducing in colonies of B.

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occidentalis. Additional surveys at historic and potential sites on National Forests and BLM Districts where B. suckleyi is Suspected or Documented, as well as thorough searches in areas with recent B. occidentalis observations, are needed to identify B. suckleyi’s current distribution in Oregon and Washington.

Meadows and grasslands with abundant floral resources are appropriate habitat for this species – particularly at higher elevations. Bombus suckleyi is a generalist forager and has been reported to visit a wide variety of flowering plants in Oregon and Washington. The plant genera most commonly associated with B. suckleyi observations or collections include: "Aster", Chrysothamnus sp., Cirsium sp., and Solidago sp. (Williams et al. 2014). There are also several records of this species visiting Centaurea repens (Richardson 2017). The plant genera most commonly associated with B. occidentalis (its documented host) observations or collections from Oregon and Washington include: Trifolium (20 observations), Cirsium (12), Rubus (7), Solidago (6), Epilobium (5), Spiraea (5), Tilia (5), Cicuta (4), Heracleum (3), and Plantago (3) (Williams et al. 2014).

Although meadows 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. suckleyi or B. occidentalis’ 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: The timing for surveys for B. suckleyi will differ from the timing for most other bumble bees. This is largely because there is no worker caste to target, and this can make B. suckleyi difficult to detect. There are two opportunities to target detection of B. suckleyi – during the peak of the female flight period, and during the peak of the male flight period. Males are likely to be generally more abundant, and around in the landscape for longer, than females. But males will also be a bit more difficult to identify in the field, or from photos. The colony life cycle for B. suckleyi can begin as early as mid-April and can last until mid-October. According to Williams et al. (2014), the flight period for B. suckleyi females range from early April to October, with a peak in mid-June. The flight period for males is from mid-May to September with a peak in mid-August (Williams et al. 2014). The peak flight period at a specific site will vary by elevation and local climatic conditions.

Identification: This species does not have a worker class, and all females are reproductive members of the population. Since populations of this species are apparently very low – and thus highly imperiled (Hatfield et al. 2015), each individual

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female is likely critical for the continued existence of the species in Oregon and Washington. We strongly recommend photo documenting females of this species (see guidelines above). Males are less critical to the population, and limited collection is recommended to verify the presence of the species.

Females (adapted from Williams et al. 2014) : In Oregon and Washington, Bombus suckleyi will be most easily confused in the field by Bombus insularis and Bombus flavidus which are both also cuckoo bumble bees, but more abundant and widespread throughout both states. The key color pattern differences for these three species are in the color of the face and head. The face and vertex (top of the head – above the antennal bases) of B. suckleyi are black with at most a few yellow hairs mixed on the vertex. B. insularis has a yellow face and vertex; B. flavidus has a yellow vertex. While the descriptions above for these species can be diagnostic, color patterns vary significantly within species and it will be important to verify sightings using key morphological characters. Key morphological characters for B. suckleyi: T6 is at most weakly curved under the metasoma – the apex points ventrally, not distally (contrast B. flavidus); Sternal Segment (S)6 has lateral keels that are anteriorly broadly flattened in section, and v-shaped in profile (contrast B. insularis). Note: Female B. suckleyi can be separated from all true bumble bees by the hind leg tibia; B. suckleyi females lack a corbicula, instead the outer surface of the tibia is convex and densely hairy (see Williams et al. 2014 for photos).

Illustrations of adult females of Bombus suckleyi (left), B. insularis (center) and B. flavidus (right). Note the differences in the vertex (top of head), and face. There are other color variations of all three species – see Williams et al. (2014) for more detail. Illustrations by Elaine Evans and Rich Hatfield, the Xerces Society, used with permission.

Males (adapted from Williams et al. 2014) : In Oregon and Washington, Bombus suckleyi will be easily confused in the field by several other species of male bumble bees. B. suckleyi can be separated from all true bumble bees by the hind leg tibia. The shape of the tibia will be similar, but true bumble

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bees will have a hairless area on the tibia, while the cuckoo bumble bees will have a hind leg tibia that is densely hairy. B. suckleyi will be difficult to separate from other male cuckoo bumble bees by color pattern alone; there is significant overlap in the color patterns of B. suckleyi with B. insularis and B. flavidus. B. flavidus does have pale orange hairs on T6-7, and B. insularis generally has a distinct patch of black hairs centrally on T4; T4 on B. suckleyi is yellow – with only a minority of black hairs. These color patterns would ideally be confirmed with morphological characteristics. These characteristics involve the male genitalia, and often need to be extruded to be observed properly. It is important to note that these characters are somewhat relative and can be challenging, even for a trained eye. 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

Richardson L. 2017. Data Contributors. Available from http://www.leifrichardson.org/bbna.html (accessed February 22, 2017).

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, Sheppard W, Koch J. 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).

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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.

The Xerces Society, Wildlife Preservation Canada, York University, The Montreal Insectarium, The London Natural History Museum, BeeSpotter. 2017. 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 February 22, 2017).

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