The role of landscape factors in bumble bee pathogen loads across regions of the eastern Nearctic

Pathogens and parasites are considered important drivers of declines of wild bumble bee populations. Transmission of pathogens and parasites can be influenced by numerous abiotic and biotic factors, such as floral resource availability, inter/intraspecific pollinator interactions, land use change, climate, and exposure to pesticides . Identifying the key factors in the landscape to address to reduce disease burden in bees is thus challenging. We evaluated loads of common bee viruses Black Queen Cell Virus (BQCV) and Deformed Wing Virus (DWV) in the bumble bee Bombus impatiens, as well as the honey bee Apis meliferra, and loads of bumble bee parasites Vairimorpha bombi and Crithidia bombi in B. impatiens, from sites representing diverse habitat types and quality across North Carolina. We assessed relationships between pathogen loads and land cover characteristics, floral quality metrics, bee community diversity/richness metrics, and weather variables to determine which landscape factors best explained variation in pathogen loads. We compared our results with a comparable dataset from Pennsylvania. The data support latitudinal difference in pathogen loads but that pathogen loads otherwise tend to be influenced by landscape factors similarly between states. In North Carolina bumble bees, there was very low prevalence of DWV (14% of samples) and no Vairimorpha (0% of samples) and C. bombi showed consistently moderate loads across North Carolina (99% of samples) but more variation in loads in Pennsylvania . Directionality of pathogen incidence by landscape factors for both bee species generally mirrored results from Pennsylvania, however, BQCV loads were impacted differently by floral resource availability metrics by species and region. Honey bees and bumble bees in North Carolina showed similar trends, but correlations were weaker for bumble bees. Together with data from the literature, our results suggest honey bee density and percent developed land tend to be associated with increased pathogen loads in North American bumble bees, but floral availability metrics and community composition and diversity have mixed effects on pathogen loads.


Gratton, Elena; Hines, Heather; Grozinger, Christina (2023). The role of landscape factors in bumble bee pathogen loads across regions of the eastern Nearctic [Data set]. Scholarsphere.



Work Title The role of landscape factors in bumble bee pathogen loads across regions of the eastern Nearctic
Open Access
  1. Elena Gratton
  2. Heather Hines
  3. Christina Grozinger
License CC BY-NC 4.0 (Attribution-NonCommercial)
Work Type Dataset
Publication Date 2023
DOI doi:10.26207/12ca-gg34
Deposited May 15, 2023




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  • Added Creator Elena Gratton
  • Added Creator Heather Hines
  • Added Creator Christina Grozinger
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