Recipient Organization
WEST VIRGINIA STATE UNIVERSITY
PO BOX 1000
INSTITUTE,WV 25112
Performing Department
Agricultural & Environmental Res Station (AERS)
Non Technical Summary
Pollination services are critical to our existence. The great majority of products made by humans are in some way dependent on the pollination of plants. For example, the value of worldwide food production dependent upon action of insect pollinators is approximately $500 billion annually. Recently, it has been found that several species of these important insects are at risk and their numbers are declining. In particular, bumble bees (Bombus spp.), the native social pollinators of the Americas, have experienced an alarming decline over the past 50 years . In the state of West Virginia, very little is known about the distribution and abundance of bumble bees. Thus, my lab has initiated an ambitious study to survey the bumble bee fauna of WV by identifying current and past trends regarding the distribution of Bombus species in the state as well as to determine what factors are most impacting bumble bees in the state and possibly causing their decline. Due to the paucity of information regarding WV bumble bees, this project will establish a foundation for our understanding of the local diversity of as well as generate valuable data regarding the possible causes of the decline of these important pollinators.The proposed project comprises 4 separate experiments, each investigating one of the possible causes of the decline of certain bumble bee species.1- To determine if a loss of preferred flora has affected the abundance of several species of bumble bees, we will create floral plots consisting of plant species preferred by bumble bees known to be in decline. This experiment's purpose is to determine whether a lack of floral resources may be responsible for the decline of these species, and more importantly, if the introduction of species that are preferred can increase the abundance of these species.2- The pathogen Nosema bombi is often cited as a causative agent in the decline of bumble bees. To ascertain the degree to which this pathogen is present in West Virginia and whether the changing demographics of different bumble bee species is because certain species can tolerate N. bombi infections better than others, we will analyze the rate of infection of this pathogen in different bumble bee species by dissecting individual foragers and examining their gut walls for evidence of Nosema infection. These data will enable us to not only determine the presence of this pathogen here in West Virginia, but also enable us to see if there are differential rates of infection in different species.3- Another hypothesis suggested to explain the decline of bumble bees is a loss of genetic variation leading to less fit populations. To test this, we will conduct a genetic analysis of 2 species that have been identified as in decline and assess their genetic variation using microsatellites. Microsatellites are tandem repeats of DNA that are highly variable and thus are excellent tools for comparing genetic variation between multiple groups. Regardless the outcome, the data from this project will increase our understanding of the current status of bumble bees in West Virginia as well as increase our overall understanding of factors affecting the spatial distribution and abundance of these important insects. The findings will significantly improve our understanding of factors contributing to bumble bee declines worldwide. At the very least, the results of this project will contribute to the increasing volume of knowledge that will lead to solutions to the problem of bumble bee decline.
Animal Health Component
5%
Research Effort Categories
Basic
95%
Applied
5%
Developmental
(N/A)
Goals / Objectives
Bumble bee species are declining worldwide. The question of what is causing the losses of certain species remains elusive. Further complicating this issue is that some species are thriving while others are declining. The goal of this project is to understand the factors that are impacting the bumble bee community in West Virginia. The project will, upon its completion, provide significant insights toward determining the cause of bumble bee declines both here in WV and across the globe.The project objectives are as follows:1- To determine whether a changing floral community is responsible for the decline of Bombus species in WV.2-To determine whether the spatial abundance of certain Bombus species can be increased by creating floral patches comprising plant species known to be preferred by those species.3- To determine the impact that the pathogenic microsporidian Nosema bombi has on bumble bees in WV.4-To use microsatellites to compare genetic variation of B. auricomus and B. pensylvanicus to ascertain its role in the divergent population trends in these two species.
Project Methods
1- Effect of floral community on the bumble bee pollinator communityThe primary literature and plant collection databases will be used to create a virtual map of West Virginia for native and non-native species over the past century. These maps will be used to determine the spatial distribution of plants throughout the state over this period. These data will then be correlated with the data my lab has already collected for the bumble bees in the state over the same time period. The goal is to determine whether there has been a substantive change in the flora of the state to consider it a causative factor in the decline of several species of bumble bees in the state.2- Creating targeted floral patches to ascertain bumble bee local abundanceIf a loss of suitable forage is a cause for the apparent decline of certain bumble bee species, providing preferred flora may enable us to better understand why these species are no longer as abundant as they once were.For this experiment, 3 raised flower beds measuring 12'X12'X2' will be constructed and placed at 3 sites on the West Virginia State University campus. Each plot will contain a mixture of 6 species that are known to be preferred by long tongued bumble bees. Following a period of establishment in a greenhouse, young plants will be moved to the raised beds and allowed to continue their growth and development. When flowering has commenced, foraging observations will begin. At 3 separate time periods each day. Observers will focus on a 3'x3' area during each observation period and will collect data on bee species, duration of visit and frequencies of repeat visitations. Additional data will be collected on bee visitors to native plants in the areas outside of the plots. This will enable a determination of whether the targeted approach was successful in recruiting different bumble bee species than those that are the dominant species on campus, B. bimaculatus and B. impatiens.3- Bombus pathogen loadsInfections of N. bombi have been indicated as a possible causative factor in the decline of bumble bees and are identified by the presence of mature infective spores that develop in the cytoplasm of cells in the midgut. For this experiment, we will examine the Nosema loads of 4 Bombus species (B. auricomus, B. bimaculatus, B. griseocollis, and B. impatiens) collected from different locations at different periods of the colony cycle. To perform this analysis, field-collected worker bees will be dissected and their intestinal tracts will be removed and smeared on individual microscope slides. Smears will be air dried and exposed to 95% ethanol for 5 minutes then suspended in 10% buffered Giemsa stain for 10 minutes. After the stained smear has dried, the sample will be screened using phase contrast microscopy. Presence, absence, and quantification of spores will be determined by examining the number of spores identified via inspection of 20 visual fields. These data will be analyzed by performing ANOVA on JMP software.4- Microsatellite analysis of two divergent Bombus speciesStudies have shown that declining bumble bees often have lower levels of genetic variation relative to those that are not declining. In West Virginia, B. pensylvanicus is in decline as it is over most of North America. B. auricomus is not declining in West Virginia but it is declining in other parts of North America. This experiment will be performed to determine if there is a difference in the levels of genetic variation in these two long-longued bumble bee species and if this difference can explain differing population trends in these two species.B. auricomus and B. pensylvanicus collected from multiple locations will have a single metathpracic leg removed and placed in 95% ethanol to avoid destructive sampling. DNA will be extracted using Qiagen Blood and Tissue Kits. Samples will be genotyped at 11 microsatellite loci. Electrophoresis will be performed using an ABI 3730xl capillary DNA sequencer and alleles will be scored using GENEMAPPER software.For each component of the project, undergraduate students will be trained to independently perform various experiments:Use plant and insect databasesIdentify different bumble bee speciesDissect bumble bees and remove the alimentary canal intactPerfect smearing technique and appropriately stainExtract DNA, perform PCR, and use capillary DNA sequencesAnalyze microsatellite fragments