SPECIES FACT SHEET

Scientific Name: Bombus franklini (Frison, 1921)

Common Name: Franklin’s Bumble BeePhylum: ArthropodaClass: InsectaOrder: HymenopteraFamily: ApidaeTribe: BombiniGenus: BombusSubgenus: Bombus sensu stricto (ITIS 2018)

Conservation Status: Global Status: G1 (Last reviewed 04 Sep 2009)National Status: N1 (United States): (Last reviewed 30 Aug 2007)State Status: S1 (Oregon), S1 (California)(NatureServe 2018) IUCN Red List Category: Critically Endangered(IUCN 2018)

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 (Thorp et al. 1983; Michener 2007; 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; records from Oregon are largely confined to Klamath, Jackson, Josephine, and Wallowa counties (Ascher and Pickering 2018).

Bombus franklini is readily distinguished from other bumble bees in its range by the extended yellow on the anterior dorsal side of the thorax which extends well behind the wing bases and forms an inverted U-shape around the central patch of black, lack of yellow on the abdomen, yellow on the vertex (top of the head), and white on the fifth tergal (dorsal abdominal) segment. Other bumble bees with similar color patterns in the range of B. franklini have the yellow extending back to the wing bases or only slightly beyond. Females of B. fervidus which have black hair on the face also have black hair on the vertex in contrast to the yellow hair on the vertex in B.

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franklini. Additionally, B. fervidus have yellow on the abdomen while B. franklini does not, and have a long face in contrast to the short face of B. franklini. Females of B. occidentalis are similar to B. franklini in the short, round faces, and most B. occidentalis females have predominantly black hairs on the vertex, though many have at least some yellow hairs mixed in; this contrasts with B. franklini which has predominantly yellow hairs on the vertex. While B. occidentalis females are variable in color pattern, the closest matching patterns to B. franklini will have significantly more pale or white hairs on tergal segments 4 and 5, while the pale hairs in B. franklini are reduced to at most tergal segment 5. The differences between these species and B. franklini are noted in the detailed description below (descriptions compiled from Williams et al. 2014).

Queens & workers: Bombus franklini queens are 22-24 mm in length, the worker is 10-17 mm in length. Face round with area between bottom of compound eye and base of mandible (= malar space) just shorter than wide; hair of the face black with yellow hairs intermixed above and below antennal bases. Hair on top of head (= vertex) yellow. Hair of thorax (= mesosoma) on anterior two-thirds above (= scutum) yellow extending rearward laterally inside and beyond the wing bases (= tegulae) to rear third (= scutellum), but interrupted medioposteriorly by inverted U-shaped patch of black; hair on posterior third (= scutellum) black above; hair of lateral thorax (= mesopleura) black, except for small patch of yellow in upper anterior corner in area of pronotal lobes. Hair of abdomen (= metasoma) black except for whitish or silvery hair at sides and apex of 5th plate above (= tergum 5, = T-5).

Males: The color patterns of the males of this species are similar to females, differing as follows: malar space as long as wide, face below antennae with predominantly yellow hair, and tergum 6 with some pale hair laterally.

Technical keys, including color pattern illustrations of B. franklini and species that it might be confused with, are presented in Stephen (1957), Thorp et al. (1983), and Williams et al. (2014).

Life History:Bombus franklini is a primitively eusocial bumble bee. Like all other true bumble bees (those not in the subgenus Psithyrus), this species lives in colonies consisting of a queen and her immature and adult offspring: 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 wax structures to store nectar and to enclose the eggs and pollen; forming a mass of pollen mixed with nectar on which to lay eggs.

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The nesting biology of B. franklini is undescribed, but, like other members of the subgenus Bombus sensu stricto, it probably nests underground in abandoned rodent burrows, or, occasionally, in clumps of grass on the ground (Plath 1927; Hobbs 1968; Thorp et al. 1983; Laverty and Harder 1988; Macfarlane et al. 1994).

Once the colony has been initiated by the queen and the first brood of female workers has 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). At their peak, average Bombus sp. 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). Two colonies of B. franklini initiated in the laboratory and set out to complete development in the field contained over 60 workers by early September, and probably produced over 100 workers by end of season (Plowright and Stephen 1980).

Near the end of the colony cycle, reproductive queens and males are produced. Male bumble bees patrol selected territories, producing a queen-attracting scent, which they deposit in suitable places and replace if it rains. When a female locates a male patrol-area, she remains still until a male finds her, and mating usually takes place on vegetation or the ground. Queens usually mate with only one male, but males may mate with multiple queens. After mating, the queens feed to build up their fat bodies and search for a suitable location (hibernacula) to overwinter, usually burrowed a few centimeters underground. At the end of the colony season the founding queen, all workers, and males die and the inseminated hibernating new queens are left to carry on the line into the following year.

In Bombus sensu stricto, queen production is complicated, apparently depending on a switch point when the first males are produced. This switch point usually occurs when queens cease producing a pheromone that inhibits workers from laying haploid (male producing) eggs, and is followed by a “competition point” when some workers initiate egg laying and compete with the queen for survival of their male progeny. An early switch point results in more males and fewer queens, while a late switch point results in larger colonies, more queens, and fewer males (Duchateau and Velthius 1988).

The flight season of B. franklini is from April to the end of September (Williams et al. 2014); a few individuals have also been encountered in October (Southern Oregon University Bee Collection 2012).

Bumble bees, including B. franklini, are generalist foragers and have been reported visiting a wide variety of flowering plants. B. franklini has a short tongue, and thus is best suited to forage at open flowers with short corollas,

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although it has been observed nectar robbing (chewing through the side of the petals, thus avoiding contact with the reproductive parts of the flower) plant species with longer corolla tubes. According to Williams et al. (2014), important food plants for B. franklini are in the genera Agastache, Centaurea, Ceonothus, Eriogonum, Eschscholzia, Lupinus, Monardella, and Vicia.

Range, Distribution, and Abundance: Franklin’s bumble bee has the most limited geographic distribution of any bumble bee in North America and possibly the world (Williams 1998). It is known only from southern Oregon and northern California between the Coast and Sierra-Cascade Ranges. Stephen (1957) recorded it from the Umpqua and Rogue River Valleys of Oregon. Thorp et al. (1983) recorded it from northern California and suggested its restriction to the Klamath Mountain region of southern Oregon and northern California. Its entire distribution, including historic populations and recent range extensions (Thorp 1999; 2001; 2004) can be covered by an oval of about 190 miles north to south and 70 miles east to west between 122o to 124o west longitude and 40o 58’ to 43o 30’ north latitude. It is known from Douglas, Jackson, and Josephine counties in Oregon and Siskiyou and Trinity counties in California. Elevations of localities where it has been found range from 540 feet (162 m) in the north to above 7800 feet (2340 m) in the south of its historic range. Although the number of populations that existed prior to 1998 is unknown, there are several historical records for this species, both published and in museums, including two in 1925 (Gold Hill and Roseburg, OR), one in 1930 (Roseburg, OR), two in 1950 (Gold Hill and Medford, OR), two in 1958 (Ashland, OR), two in 1968 (Mt. Ashland and near Copper, OR), one in 1980 (Ashland, OR), two in 1988 (Ashland and Merlin, OR), two in 1989 (Hilt and Yreka, CA), four in 1990 (Ashland, Ruch, Central Point, and Gold Hill, OR), one in 1992 (Ashland, OR), two in 1997 (Roxy Ann Peak near Medford and Ashland Pond in Ashland, OR), and four in 1998 (Roca Canyon in Ashland, Lost Creek Reservoir, and Grizzly Peak near Shale City, OR). Additional records with unknown dates and/or localities are also available, including the 1917 type specimen whose locality (Nogales, AZ) has been determined to be erroneous (Thorp 1970).

Evidence for the decline in this species is based on intensive and extensive surveys, primarily by R.W. Thorp (Thorp 1999, 2001, 2004, 2005a, 2005b, 2008) from 1998 through 2017. Surveys for the Bureau of Land Management were also conducted in 2006; 16 sites with optimal habitat for B. franklini were each surveyed twice (Code & Haney 2006). R.W. Thorp surveyed from nine to seventeen historic sites (average 13.8 sites) per year from 1998 to 2009; reports of surveys completed since 2009 are not available, although it has been confirmed that no B. franklini have been found in surveys that have occurred since 2009 (Thorp 2018, pers. comm.). Dr. Thorp also surveyed from six to nineteen additional sites (average 12.8 sites) each year, some of

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which were visited more than once per year and some of which were visited in multiple years.

Between 1998 and 2005, the number of sightings of B. franklini throughout its range declined precipitously from ninety-four individuals in 1998 to twenty in 1999, nine in 2000, and one in 2001. In Oregon, twenty were found in 2002, although only three were sighted in 2003, all at a single locality at Mt. Ashland in southern Oregon. None were found in 2004 and 2005 in Oregon or California. A single worker of B. franklini was sighted in 2006 at Mt. Ashland in Oregon, which is the same locality where B. franklini were found in 2003 (Table 3). None have been found from 2007-2017. R.W. Thorp’s unpublished surveys have revealed that, since 1998, the populations have decreased to the point of being not seen at all in 2004 or 2005, with only one individual found in 2006. Because extensive surveys of the area within which B. franklini exists have, as of 2006, uncovered only one individual, but similar surveys in the first three years (1998-2000) uncovered individuals at many historic and seven new sites, it can be concluded that the extent of population is decreasing severely. No B. franklini were found during the BLM search effort in 2006 (Code & Haney 2006). BLM/Forest Service Land:

Documented: Bombus franklini has been documented on the Rogue River-Siskiyou National Forest and on BLM land in the Medford District.

Suspected: In Oregon, this species is suspected in the Roseburg BLM District and the Klamath Falls Resource Area of Lakeview BLM District, based on the proximity of records.

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, Bombus franklini 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.

Nest sites: The nesting biology of B. franklini is unknown, but, like other members of the subgenus Bombus sensu stricto, it probably nests underground in abandoned rodent burrows, or, occasionally, in clumps of grass on the ground (Plath 1927; Hobbs 1968; Thorp et al. 1983; Laverty and Harder 1988; Macfarlane et al. 1994).

Floral Resources: B. franklini requires habitat with a sufficient supply of floral resources to provide continuous blooming throughout the colony season.

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Bumble bees are generalist foragers, gathering pollen and nectar from a wide variety of flowering plants. Bombus franklini have been observed collecting pollen on lupine (Lupinus) and California poppy (Eschscholzia), and nectaring on horsemint (Agastache) and mountain penny-royal (Monardella) (Thorp 2004). They may collect both pollen and nectar from vetch (Vicia) and also rob nectar from this plant (P. Schroeder 2006, pers. comm.).

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

Landscape level habitat quality has been shown to influence bumble bee species richness and abundance, indicating that isolated patches of habitat are not sufficient to fully support bumble bee populations (Hatfield & LeBuhn 2007; Öckinger & Smith 2007). Additionally, since B. franklini probably requires abandoned rodent borrows or clumps of grass for nesting, population sites may be limited by the abundance of rodents and the presence of undisturbed grassland.

Threats:Bombus franklini is in imminent danger of extinction. Extensive surveys from 1998-2017 have demonstrated that there has been a precipitous decline in the number of individuals and localities. In 1998, 94 individuals were found at 8 sites, while in the past 11 years, only one individual has been observed in surveys. Threats that have altered the habitat of B. franklini include agricultural intensification, water impoundments, livestock grazing, urban development, fragmentation of landscapes, natural and introduced fire, and invasive species. These threats are even more significant when the range of an animal, such as B. franklini, has been reduced to just a few locations. 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). 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 since genetic diversity already tends to be low in this group 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. 2011b and Lozier et al. 2011). In this case, habitat loss or degradation at any one site has a more pronounced impact on the extinction potential of this species. The threats to this species are outlined as follows:

Disease: The recent declines of Bombus franklini and its close relatives are hypothesized to be primarily due to a selectively virulent strain of the microsporidian Nosema bombi acquired from the commercially reared and

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closely related European large earth bumble bee, Bombus terrestris (Thorp 2003; Thorp & Shepherd 2005; National Research Council 2007; Cameron et al. 2011b). Commercially reared bumble bees frequently harbor pathogens and their escape from greenhouses can lead to infections in native species (Colla et al. 2006; Otterstatter and Thomson 2008; Durrer & Schmid-Hempel 1994; Goka et al. 2001; 2006). 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, although recent evidence suggests that while N. bombi was very likely distributed to wild bumble bees throughout North America by commercial bumble bees, it does not appear that the strain distributed was novel, or exotic (Cameron et al. 2016). Other pests and diseases found in commercial bumble bees that could be leading to the continued decline in North American bumble bees include the protozoan parasite Crithidia bombi (Brown et al. 2003; Otterstatter & Whidden 2004), the tracheal mite Locustacarus buchneri (Otterstatter & Whidden 2004), and the RNA virus known as Deformed Wing Virus (DWV) (Fürst et al. 2014). Habitat Alteration: Modifications to bumble bee habitat from over grazing by livestock can be particularly harmful to bumble bees (reviewed in Hatfield et al. 2012) by removing floral resources, especially during the mid-summer period when flowers may already be scarce. In addition, livestock may trample nesting and overwintering sites, or disrupt rodent populations, which can indirectly harm bumble bees. Indirect effects of logging (such as increased siltation in runoff) and recreation (such as off-road vehicle use) also have the potential to alter meadow ecosystems and disrupt B. franklini habitat.

Additional habitat alterations, such as conifer encroachment resulting from fire suppression (Schultz & Crone 1998; Panzer 2002; 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), and urban development (Jha & Kremen 2012; Bhattacharya et al. 2003 may threaten B. franklini.

Pesticide Applications: 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).

Global climate change: A changing climate may cause shifts in the range of host plant species available to pollinators, and can be especially detrimental to pollinators when combined with habitat loss (National Research Council

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2007). Changes to the climate that are expected to have the most significant effects on bumble bee populations include: increased temperature and precipitation, increased drought, increased variability in temperature and precipitation extremes, early snow melt, and late frost events. These changes may lead to increased pathogen pressure, decreased resource availability (both floral resources and hibernacula), and a decrease in nesting habitat availability due to changes in rodent abundance or distribution (Cameron et al. 2011a). Variability in climate can lead to phenological asynchrony between bumble bees and the plants they use (Memmott et al. 2007; Thomson 2010). Furthermore, as the climate warms in North America, range contraction from the south is a severe threat to the continued existence of North America’s bumble bees (Kerr et al. 2015), and B. franklini in particular due to its limited range. Although the very large size of the queens suggests that the dispersal ability of this species may be greater than that of other bumble bees within its range, the patchy distribution of its remaining habitat might hinder dispersal made necessary by climate change.

Competition from honey bees ( Apis mellifera ): While there remains a need for additional research, there is evidence that honey bees can potentially impact the native bee community by removing available supplies of pollen and nectar (Anderson & Anderson 1989; Paton 1990; 1996; Wills et al. 1990; Dafni & Shmida 1996; Horskins & Turner 1999; Cane and Tepedino 2017). Thomson (2004, 2006) conducted competition experiments on Bombus occidentalis colonies placed at three distances from introduced honey bee hives. These studies found decreased foraging activity, especially for pollen, and lowered reproductive success in B. occidentalis colonies nearest the Apis hives. Evans (2001) found the same results in a similar study with B. impatiens colonies in Minnesota. The long-term implications of this shift in resource use are not entirely clear, although the growing body of research demonstrates negative competitive effects of honey bees on bumble bees, including lower reproductive success, smaller body size, and changes in bumble bee foraging behavior – notably a reduction in pollen gathering (Evans 2001; Goulson et al. 2002; Thomson 2004; 2006; Paini & Roberts 2005; Walther-Hellwig et al. 2006; Goulson & Sparrow 2009; Elbgami et al. 2014). 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:

Inventory: Comprehensive surveys are needed to understand the size and range of the remaining population; although very few individuals have been observed, further investigation should be done to reveal precisely how many Bombus franklini are remaining.

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Research: Research is needed to evaluate the status of this species throughout its range and to monitor, sample, and conduct population estimates of extant populations of Bombus franklini. Conduct research aimed at increasing understanding of the pathology and control of Nosema bombi [Microsporidia] and other potential disease organisms (such as Locustacrus buchneri [Acarina] and Crithidia bombi [Protozoa]). Focus research on elucidating the virulence and cross-infectivity of strains of these disease organisms, especially Nosema bombi, between honey bees, commercially reared and wild bumble bee species in order to better assess the ecological risks of trafficking managed crop pollinators.

Management: All habitat known to previously host Bombus franklini should be protected and managed to include plentiful food (pollen and nectar resources such as Lupinus, Eschscholzia, Agastache, Monardella, Vicia), abandoned rodent burrows in which to nest, proximity to water sources (lakes, rivers, streams, seeps) for prolongation of flowering season of plant food sources, and a safe place to overwinter. 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 (availability of nectar and pollen throughout the colony season and availability of underground nest sites and hibernacula). All efforts should be made to prevent the spread of disease from honey bees and commercially reared and managed bumble bee colonies to native populations.

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

Version 2Prepared by: Michele Blackburn and Rich Hatfield, the Xerces Society for Invertebrate ConservationDate: June 2018Reviewed by: Rich Hatfield, the Xerces Society for Invertebrate Conservation Date: June 2018

Version 1

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Prepared by: Scott Black, Sarina Jepsen, Elaine Evans, Sarah Foltz, the Xerces Society for Invertebrate Conservation; Robbin Thorp, University of California- DavisDate: June 2009

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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 41:79.

Laverty, T. and L. D. Harder. 1988. The bumble bees of eastern Canada. Canadian Entomologist 120: 965-987.

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.

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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. 2nd edition. The Johns Hopkins University Press, Baltimore, MD. 972 pp.

National Research Council. 2007. Status of Pollinators in North America. The National Academies Press, Washington, DC.

NatureServe. 2018. “Bombus franklini.” NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available at: http://www.natureserve.org/explorer. [Accessed 23 February 2018]. Öckinger, E. and H. G. Smith. 2007. Semi-natural grasslands as population sources for pollinating insects in agricultural landscapes. Journal of Applied Ecology 44: 50-59.

Otterstatter, M. C., and J. D. Thomson. 2008 Does pathogen spillover from commercially reared bumble bees threaten wild pollinators? PLoS ONE 3(7): e2771. Available At: http://www.plosone.org/doi/pone.0002771. [Accessed 7 March 2017].

Otterstatter, M. C., and T. L. Whidden. 2004. Patterns of parasitism by tracheal mites (Locustacarus buchneri) in natural bumble bee populations. Apidologie 35:351–357. Available at: http://www.edpsciences.org/10.1051/apido:2004024. [Accessed 28 February 2018].

Paini, D. R. and J. D. Roberts. 2005. Commercial honey bees (Apis mellifera) reduce the fecundity of an Australian native bee (Hylaeus alcyoneus). Biological conservation 123:103–112.

Panzer, R. 2002. Compatibility of prescribed burning with the conservation of insects in small isolated prairie reserves. Conservation Biology 16 (5): 1296-1307.

Paton, D. C. 1990. Budgets for the use of floral resources in mallee heath. In The Mallee Lands: A Conservation Perspective, J. C. Noble, P. J. Joss, G. K. Jones (eds.). Melbourne: CSIRO. 189–93 pp.

Paton, D. C. 1996. Overview of feral and managed honeybees in Australia: distribution, abundance, extent of interactions with native biota, evidence of impacts and future research. Australian Nature Conservation Agency, Canberra, Australian Capital Territory. 77 pp.

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Plath, O. E. 1927. Notes on the nesting habits of some of the less common New England bumblebees. Psyche 34: 122-128.

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

Schroeder, P. 2006. Personal communication with Robbin Thorp, Distinguished Emeritus Professor, Department of Entomology and Nematology, University of California, Davis California. Associate Professor of Biology, Southern Oregon University, Ashland, Oregon.

Plowright, R. C. and W. P. Stephen. 1980. The taxonomic status of Bombus franklini (Hymenoptera: Apidae). Canadian Entomologist 112: 475-479.

Schultz, C. B. and E. E. Crone. 1998. Fire to restore butterfly habitat? A modeling approach to management tradeoffs for the Fender’s blue. Restoration Ecology 6: 244-252.

Southern Oregon University Biology Department Insect Museum. 2012. Bumble Bee Collection, “Bombus franklini”. Available at: http://www.sou.edu/biology/insectmuseum.html. [Accessed 23 February 2018].

Stephen, W. P. 1957. Bumble Bees of Western America. Oregon State College, Agricultural Experiment Station, Technical Bulletin 40: 163pp. Thomson, D. 2004. Competitive interactions between the invasive European honey bee and native bumble bees. Ecology 85: 458-470.

Thomson, D. M. 2006. Detecting the effects of introduced species: a case study of competition between Apis and Bombus. Oikos 114: 407-418.

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

Thorp, R. W. 1970. The type locality of Bombus franklini and notes on putative Arizona records of other Bombini (Hymenoptera: Apidae).Pan-Pacific Entomologist 46:177-180.

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.

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Thorp, R. W. 1999. Franklin’s bumble bee, Bombus franklini (Frison 1921): a species of special concern. Report to USDA Forest Service, Ashland. OR on 1998 season (submitted 23 November 1999).

Thorp, R. W. 2001. Franklin’s bumble bee, Bombus franklini (Frison 1921): a species of special concern. Report to US Fish and Wildlife Service, Portland, OR on 1999-2000 seasons (submitted 14 May 2001)

Thorp, R. W. 2003. Bumble bees (Hymenoptera: Apidae): commercial use and environmental concerns. Pp. 21-40. In: K. Strickler and J. H. Cane (eds.). For nonnative crops, whence pollinators of the future? Thomas Say Publications in Entomology: Proceedings. Entomological Society of America, Lanham, MD., 204 pp.

Thorp, R. W. 2004. Franklin’s bumble bee, Bombus (Bombus) franklini (Frison). Report to US Fish and Wildlife Service, Portland, OR on 2001-2003 seasons (submitted 29 June 2004).

Thorp, R. W. 2005a. Franklin’s bumble bee, Bombus (Bombus) franklini (Frison). Report to US Fish and Wildlife Service, Portland, OR on 2004 season (submitted 29 March 2005).

Thorp, R. W. 2005b. Franklin’s bumble bee, Bombus (Bombus) franklini (Frison). Report to US Fish and Wildlife Service, Portland, OR on 2005 season (submitted 7 November 2005).

Thorp, R. W. and Shepherd, M. D. 2005. Subgenus Bombus. Latreille, 1802 (Apidae: Apinae: Bombini). In Shepherd, M. D., D. M. Vaughan, and S. H. Black (eds.) Red List of Pollinator Insects of North America. CD-ROM Version 1 (May 2005). Portland, OR: The Xerces Society for Invertebrate Conservation. Available at: www.xerces.org/Pollinator_Red_List/Bees/Bombus_Bombus.pdf. [Accessed 8 March 2018].

Thorp, R. 2018. Personal communication with Michele Blackburn, the Xerces Society for Invertebrate Conservation. Distinguished Emeritus Professor, Department of Entomology and Nematology, University of California, Davis California. June 19.

Walther-Hellwig, K., G. Fokul, R. Frankl, R. Büchler, K. Ekschmitt, and V. Wolters. 2006. Increased density of honeybee colonies affects foraging bumblebees. Apidologie 37:517–532.

Whitehorn, P. R., S. O’Connor, F. L. Wackers, and D. Goulson 2012. Neonicotinoid pesticide reduces bumble bee colony growth and queen production. Science 336: 351-352.

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

Williams, P. H. 1998. An annotated checklist of bumble bees with an analysis of patterns of description (Hymenoptera: Apidae, Bombini). Bulletin of the Natural History Museum, London (Ent.) 67: 79-152. updated at: www.nhm.ac.uk/research-curation/projects/bombus/

Williams, P. H., Thorp, R. W., Richardson, L. L., Colla, S. R. 2014. Bumble Bees of North America: An Identification Guide. Princeton University Press. 208 pp.

Wills, R. T., Lyons, M. N., and Bell, D. T. 1990. The European honey bee in Western Australian Kwongan: foraging preferences and some implications for management. Proceedings of the Ecological Society of Australia 16: 167–76.

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 (30): 10742–10746.

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.

ATTACHMENT 2: List of pertinent or knowledgeable contacts:

Robbin Thorp, Professor Emeritus, 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 for Invertebrate ConservationRich Hatfield, Xerces Society for Invertebrate ConservationJeff Lozier, University of Alabama

ATTACHMENT 3: Map of Species Distribution and proximity of records to Suspected and Documented National Forests and BLM Districts.

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Records of Bombus franklini in Oregon and California, relative to BLM and USFS land.

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Bombus franklini Records in Proximity to BLM Roseburg District

Bombus franklini Records Documented on BLM land in the

Medford District

Bombus franklini Records Documented on the Rogue River-

Siskiyou National Forest

Rogue River-Siskiyou National

Forest

Rogue River-Siskiyou National

Forest

ATTACHMENT 4: Photographs and Illustrations of Bombus franklini and similar species

Bombus franklini clockwise from top left, queen showing U-shape of yellow on thorax extending beyond the wings; queen showing side of thorax and abdomen; male showing patterning on end of abdomen; queen showing patterning on end of abdomen. Photographs by Hadel Go, Discover Life.

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Illustrations of adult females of Bombus franklini (left) and B. occidentalis (right). Note the characteristic inverted U-shape of yellow hair extending behind the wings on the thorax of B. franklini in contrast to B. occidentalis. Illustrations by Elaine Evans and Rich Hatfield, the Xerces Society, used with permission.

Illustrations of potential look alike species. Illustrations by Elaine Evans and Rich Hatfield, the Xerces Society.

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

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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, 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

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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 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. 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

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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.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 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

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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 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 franklini Where:This species has the most limited geographic distribution of any bumble bee in North America and possibly the world (Williams 1998). Bombus franklini is known only from southern Oregon and northern California between the Coast and Sierra-Cascade Ranges. The most recent observations from 2003 and 2006 have been limited to one site near Mt. Ashland in southern Oregon. Additional surveys at historic and potential sites on National Forests and BLM districts where B. franklini is suspected or documented are needed to identify this bee’s current distribution in Oregon. Open grassy coastal prairies and Coast Range meadows and grasslands with abundant floral resources are the appropriate habitat for this species (Williams et al. 2014). B. franklini is a generalist forager and has been reported to visit a wide variety of flowering plants in Oregon. The plants most commonly associated with B. franklini observations or collections include: lupine (Lupinus spp.), California poppy (Eschscholzia californica), horsemint or nettle-leaf giant hyssop (Agastache urticifolia) and mountain monardella (Monardella odoratissima) (Thorp 2004). Williams et al. (2014) report the following genera as important food plants for B. franklini: Agastache, Centaurea, Ceonothus, Eriogonum, Eschscholzia, Lupinus, Monardella, and Vicia.

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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. franklini’s preference for these plants over other flowering plants, but rather may represent the abundance of these flowers in the landscape. Other plants (including those with inconspicuous or small flowers) are worth surveying and should not be ignored.

When: Surveys should target the peak flight periods for female workers, which may occur in May, June, July, and August for Bombus franklini (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. franklini can begin as early as April and, in some cases, can last until early October (Williams et al. 2014). According to Williams et al. (2014), the flight period for B. franklini queens ranges from early April to early October, peaking in April and again in May. The flight period for workers is from mid-April to September and for males is from early July to early October; worker abundance peaks in May, June, July, and August, and male abundance peaks in September (Williams et al. 2014).

Identification:

Bombus franklini is readily distinguished from other bumble bees in its range by the extended yellow on the anterior dorsal side of the thorax which extends well behind the wing bases and forms an inverted U-shape around the central patch of black, lack of yellow on the abdomen, yellow on the vertex (top of the head), and white on the fifth tergal (dorsal abdominal) segment. Other bumble bees with similar color patterns in the range of B. franklini have the yellow extending back to the wing bases or only slightly beyond. Females of B. fervidus which have black hair on the face also have black hair on the vertex in contrast to the yellow hair on the vertex in B. franklini. Additionally, B. fervidus have yellow on the abdomen while B. franklini does not, and have a long face in contrast to the short face of B. franklini. Females of B. occidentalis are similar to B. franklini in the short, round faces, and most B. occidentalis females have predominantly black hairs on the vertex, though many have at least some yellow hairs mixed in; this contrasts with B. franklini which has predominantly yellow hairs on the vertex. While B. occidentalis females are variable in color pattern, the closest matching patterns to B. franklini will have significantly more pale or white hairs on tergal segments 4 and 5, while the pale hairs in B. franklini are reduced to at most tergal segment 5. The differences between these species and B. franklini are noted in the detailed description below (descriptions compiled from Williams et al. 2014).

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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 . [Accessed 23 February 2018].

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

Goulson, D., J. C. Stout, and A. R. Kells. 2002. Do exotic bumblebees and honeybees compete with native flower-visiting insects in Tasmania? Journal of Insect Conservation 6: 179–189.

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Illustrations of adult females of Bombus franklini (left) and B. occidentalis (right). Note the characteristic inverted U-shape of yellow hair extending behind the wings on the thorax of B. franklini in contrast to B. occidentalis. Illustrations by Elaine Evans and Rich Hatfield, the Xerces Society, used with permission.

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. [Accessed 23 February 2018].

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 at: https://irma.nps.gov/rprs/FileManager/IarAttachment?id=211202&iarID=103061 [Accessed 23 February 2018].

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.

Thorp, R. W. 2004. Franklin’s bumble bee, Bombus (Bombus) franklini (Frison). Report to US Fish and Wildlife Service, Portland, OR on 2001-2003 seasons (submitted 29 June 2004).

Williams, P. H. 1998. An annotated checklist of bumble bees with an analysis of patterns of description (Hymenoptera: Apidae, Bombini). Bulletin of the Natural History Museum, London (Ent.) 67:79-152. Updated at: www.nhm.ac.uk/research-curation/projects/bombus/. [Accessed 28 February 2018].

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

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