The researchers surveyed bumble bee populations in Kanawha County, West Virginia between May and July 2014. They identified 9 bumble bee species but found the community was dominated by just 3 species, B. impatiens, B. bimaculatus, and B. griseocollis, which accounted for over 95% of individuals. Rare species like B. terricola and B. affinis were largely absent, suggesting a decline. Diversity indices also indicated low evenness with a heavily skewed population. The results provide evidence that some bumble bee species are declining in the study area, parallel to trends in other parts of North America.

1. Abstract
The goal of our research is to assess the diversity of bumble bees (i.e., the numbers of
species and their relative abundances) and to ascertain the presence and relative
abundance of two critically endangered bumble bee species (Bombus affinis and B.
terricola), in Kanawha County. The results of this study will contribute to our
understanding of the local diversity of these insects, but will also generate valuable
data regarding the decline of these pollinators and perhaps provide insights to the
locations of refugia where they may occur in higher, sustainable densities.
Our data followed a pattern similar to that found in other regions of North America,
that being the decline of local species in the subgenera Thoracobombus and Bombus
(sensu strictu). Our survey was dominated (95% of total specimens) by very strong
populations of species in the subgenera Pyrobombus and Cullumanobombus.
Introduction
Bumble bees (Bombus spp.) are the native social pollinators of the Americas. Bumble
bees are particularly important pollinators (relative to the more familiar honey bee,
Apis mellifera) because of their ability to pollinate flowers that A. mellifera cannot and
because they are more effective pollinators of greenhouse plants. The annual
economic value of bumble bees for pollination services is in the billions of dollars
(Goulson 2003). Their long tongues and buzz-pollination capabilities make them the
sole primary pollinators of numerous important crops (Whittington et al. 2004,
MacKenzie 1988). One unfortunate feature shared by both bumble bees and honey
bees is their precipitous decline over the last 2 decades (Oldroyd 2007). In honey
bees, this decline has been attributed to a combination of symptoms (e.g., Varroa
mites, Nosema apis (a fungus), viruses, pesticides) collectively referred to as colony
collapse disorder (or CCD) (Oldroyd 2007). Unlike honey bees, CCD is not believed to
explain the decline of Bombus; rather, some unknown environmental factor has
dramatically affected the distribution and abundance of several bumble bees species,
leading to the extirpation of these insects from many areas.
Bumble bee declines have been reported from around the globe (e.g., Europe, Asia,
South America). It has been suggested that bumble bee disappearances from these
areas coincide disproportionately with regions that are being used or intensive
agriculture. In North America, some species appear to have undergone similar range
reduction and decline in abundance gradually over many decades [B. fervidus, B.
pensylvanicus, B. vagans in Ontario (Colla and Packer 2008); B. fraternus, B.
pensylvanicus, and B. vagans in Illinois (Grixti et al. 2009, Lozier and Cameron
2009)]. However, other North American species appear to have undergone rapid
population collapses within the last decade (Cameron et al. 2011).
The goal of our study is to assess the local diversity of bumble bees (i.e., the numbers
of species and their relative abundances) and to ascertain the presence and
abundance of two critically endangered bumble bee species (Bombus affinis and B.
terricola), in Kanawha County. The results of this project will contribute to our
understanding of the local diversity of these insects, but will also generate valuable
data regarding the decline of these pollinators and perhaps identify the locations of
refugia where declining species may occur in high densities than expected.
Methods
Bombus were collected from several sites throughout Kanawha County, including but
not limited to: Charleston, Institute, Cross Lanes, Nitro, Dunbar, Loudendale and
South Charleston from May – July, 2014. Most specimens were collected by aerial or
sweep netting during various times throughout the day; the great majority of those
captured were able to be identified to species and released quickly. Those that could
not be identified in the field were brought back to the lab, identified and frozen. We
did not typically return to sampling sites so as not to capture the same individuals
repeatedly. Data were collected on species identities, locations, host plants, and
frequencies. We performed Shannon and Simpson diversity analyses to determine
the relative frequencies of each species. Of particular interest to us was the relative
abundance of two Bombus species that have declined most precipitously, B. terricola
and B. affinis. These once common species have become increasingly rare and have
completely disappeared from many areas from which they once ranged.
Discussion
Several species of bumble bees have been on the decline for at least the last 50 years;
but it is believed this phenomenon has become much more pronounced over the last
2 decades (Cameron et al. 2011). We are investigating this phenomenon in West
Virginia, where the status of bumble bees in the state is not well known. This project
is the first of a series that we anticipate expanding to cover the entire state within the
next 3 – 4 years. The focal area for our research was Kanawha County, and though
this is a relatively small area, our data parallel those from other parts of North
America that have been surveyed and reveal a very likely pattern of decline for
several species of Bombus in this area. The two species that have become the
exemplars for the decline of bumble bees in the eastern part of North America, B.
terricola and B. affinis (Colla and Packer 2008) were largely absent from our survey.
Indeed, we were only to collect a single individual of B. terricola (from South
Charleston) and not a single B. affinis over the duration of our study. Considering the
breadth of our coverage, unless there are very significant undiscovered refugia for
these species, they are most definitely very scarce and in the case of B. affinis,
possibly extinct from this area. On a more positive note, three local species (B.
bimaculatus, B. impatiens and B. griseocollis) are doing very well. In fact, these 3
species represented 95% of the total Bombus surveyed. This is a pattern that has
been observed in other studies as well and so was not a surprising result. Our
diversity analyses reinforced our data indicating a highly skewed bumble bee
community. Shannon indices typically fall within the range of 1.5 and 3.5, with the
higher values correlating to higher levels of species “evenness”. As expected, our
Shannon index value of 1.838 is very low and thus indicative of a very uneven
bumble bee community that is heavily skewed to one or a few species. The other
diversity analysis, the Simpson index take evenness and abundance both into account
and thus measures the probability of two of the same species being collected
randomly. This value ranges from 0 – 1, with higher values correlating to lower
diversity. Our Simpson index was a 0.324, suggesting a reasonable level of diversity
for our study area. Considering what is measured by the Simpson index, this value
was not surprising either. Since the overwhelming majority of Bombus collected were
from 3 species, the chance of selecting a second of any of those would be fairly high
as well. In the field it was quite frequently the case that all day was spent collecting B.
impatiens, B. griseocollis, B. bimaculatus and nothing else.
While it is apparent that as a whole, bumble bees are declining, it is equally apparent
that whatever is lowering the fitness of many Bombus, does not affect all species
equally (Lozier and Cameron 2009). Contributing to the mystery of the disappearing
bumble bees is the fact that it may have a phylogenetic basis (many of the most
severely threatened species are in the subgenera Bombus (s.s.) and Thoracobombus).
Though there have been many hypotheses proposed to explain the declines observed
in bumble bees (pesticides, Nosema bombii infections, environmental pollutants) the
actual cause remains elusive. We are hopeful that the findings from this study will
contribute substantially to our understanding of this ecological catastrophe.
References
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widespread decline in North American bumble bees. Proc. Natl. Acad. Sci. USA 108:662-667.
Colla S, Packer L. 2008. Evidence for decline in eastern North American bumblebees (Hymenoptera:
Apidae), with special focus on Bombus affinis Cresson. Biodivers. Conserv. 17:1379-1391.
Goulson D. 2003. Effects of introduced bees on native ecosystems. Annu. Rev. Ecol. Systemat. 34:1-26.
Grixti JC, Wong LT, Cameron SA, Favret C. 2009. Decline of bumble bees (Bombus) in the North
American Midwest. Biol. Conserv. 142:75-84.
Lozier JD, Cameron SA. 2009. Comparative genetic analyses of historical and contemporary
collections highlight contrasting demographic histories for the bumble bees Bombus pensylvanicus
and B. impatiens in Illinois. Mol. Ecol. 18:1875-1886.
MacKenzie KE. 1994. The foraging behavior of honey bees (Apis mellifera) and bumble bees (Bombus
spp.) on cranberry (Vaccinium macrocarponAit). Apidologie 25:375-383.
Oldroyd BP. 2007. What's Killing American Honey Bees? PLoS Biol 5(6): e168.
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Acknowledgements
We thank Amanda Carte and Michael McClain for assistance with collecting and
identifying specimens. This research was supported by The West Virginia State
University Faculty Development Fund, The Robert McNair Scholars Program and The
Teacher Research Experience for the Advancement of Knowledge program (TREK).
Bumble bees of Kanawha County, WV, with emphasis on two endangered species
Erica Bickham1, Hunter Aliff2 and Sean A. Collins1
Results
We collected over 600 bumble bees over the duration of the project. Our survey
identified 9 Bombus species (Figure 1), of which, three were overwhelmingly
dominant (B. impatiens, B. bimaculatus and B. griseocollis). These 3 species
represented over 95% of the species observed and collected during the study period
(see Figure 1; Table 1). The diversity indices we calculated, as expected, suggested a
very unevenly distributed bumble bee fauna (Table 1). The values for the two
Simpson diversity indices (basic and reciprocal) suggest a bumble bee community
that is heavily skewed toward one or a very few species (Table 1).
Figure 1: Bombus species identified from WV during the study period (May – July 2014). Species
names are color coded according to subgenus: Pyrobombus are black, Bombus (s.s.) is green,
Cullamanobombus is red, Thoracobombus are blue and Bombias is purple. Studies have suggested
that Thoracobombus and Bombus (s.s.) have declined more rapidly than the other subgenera and that
populations of many species in the Pyrobombus have have been least affected.
Species N Frequency
B. auricomis 12 0.02
B. bimaculatus 212 0.35
B. fervidus 14 0.02
B. griseocollis 113 0.19
B. impatiens 242 0.41
B. pensylvanicus 2 < 0.01
B. perplexus 1 < 0.005
B. terricola 1 < 0.005
B. vagans 2 < 0.01
Shannon Index: 1.838
Simpson Index: 0.324
Table 1: Frequency data for each Bombus species collected and identified during the study period
(see Figure 1 for images of each species). Results of tests for overall diversity and evenness of the
bumble bee fauna for the study area are listed below the table.
B. impatiens B. bimaculatus
B. vagans
B. pensylvanicus B. fervidus
B. griseocollis
B. auricomus
B. terricola
B. perplexus
West Virginia State University1, Nitro High School2

2. B. auricomus B. bimaculatus B. griseocollis B. impatiens B. pensylvanicus
B. impatiens B. griseocollis B. auricomus B. bimaculatus B. pensylvanicus B. fervidus B. terricola B. vagans
B. perplexus
B. perplexus