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ARS Home » Pacific West Area » Logan, Utah » Pollinating Insect-Biology, Management, Systematics Research » Research » Research Project #441774

Research Project: A Holistic Approach to Determining the Impact of an Established Exotic Pollinator, Bombus impatiens, on Bumble Bee Health in the Pacific Northwest

Location: Pollinating Insect-Biology, Management, Systematics Research

Project Number: 2080-21000-019-046-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Feb 1, 2022
End Date: Jan 31, 2026

Commercially available bumble bee (Bombus) colonies pollinate hothouse and open field crops in the USA, but mounting evidence indicates that they can negatively impact the health and persistence of native Bombus should individuals escape into the wild. The common eastern bumble bee, Bombus impatiens, is a commercially produced species that has escaped from culture and is rapidly expanding outside of its endemic range of eastern North America. The introduction and establishment of commercially produced non-native Bombus species outside of agricultural settings has been correlated with increased competition for floral resources, pathogen spread, and the decline of some native Bombus. It is not known how the invasion of B. impatiens will impact native Bombus communities in the Pacific Northwest, and what characteristics of its biology contribute to its rapid expansion. We propose to characterize the impact of B. impatiens on native Pacific Northwest Bombus communities by measuring rate of B. impatiens spread, Bombus community structure, native bumble bee colony density, competition for floral resources, pathogen loading and diversity, and immune response of native congeners. The overall objective of this proposal is to determine key factors that predict the spread of non-native B. impatiens in the Pacific Northwest and its impact on the ecology, behavior, and pathogen profile of native Bombus communities. The central hypothesis for the proposed research is that feral B. impatiens populations will impact native Bombus abundance, foraging behavior, pathogen/parasite diversity, and immune response both via resource competition and pathogen spillover. Our hypothesis is supported by preliminary findings which indicate that B. impatiens is well established in the Pacific Northwest and that Bombus pathogen/parasite diversity is high in areas that use commercial B. impatiens colonies for crop pollination. Specific Aim #1. Determine the distribution and expansion rate of feral B. impatiens in the Pacific Northwest and impacts on native Bombus community structure. Specific Aim #2: Determine the magnitude, mechanism, and effect of resource competition between B. impatiens and native Bombus. Specific Aim #3: Identify the parasites and pathogens of the Pacific Northwest Bombus community where B. impatiens is present and absent, and potential impacts of pathogen load and resource abundance on the generalized immune response of the native species. The proposed research is innovative, urgent, and high-impact. It is innovative to combine community and landscape ecology, network analysis, population genomics, pathology, and immunogenetics to examine the effect of an invasive species on native species. In particular, a study that takes a holistic approach to determine the effect of invasive species on native bee health is unprecedented. Furthermore, the proposed research is urgent given that B. impatiens is rapidly expanding south throughout the Pacific Northwest, and has the capacity to spread into Oregon and California, states with significant agricultural economies and home to several imperiled Bombus species.

Specific Aim #1. Determine the distribution and expansion rate of feral B. impatiens in the Pacific Northwest and impacts on native Bombus community structure. Study 1.1. Determine the distribution and community structure of native Bombus and B. impatiens in the Pacific Northwest. We will conduct passive and active surveys of Bombus using 150 Japanese Beetle Traps (JBTs) and netting throughout northern WA. We will test for the effect of B. impatiens presence/absence, location, and year on each community with biodiversity metrics.