La Trobe
16936_Hedtke,S_2015.pdf (1.88 MB)

Introduction of Non-Native Pollinators Can Lead to Trans-Continental Movement of Bee-Associated Fungi

Download (1.88 MB)
journal contribution
posted on 2022-03-30, 05:35 authored by Shannon HedtkeShannon Hedtke, EJ Blitzer, GA Montgomery, BN Danforth
Bees are essential pollinators for many flowering plants, including agriculturally important crops such as apple. As geographic ranges of bees or their host plants change as a result of human activities, we need to identify pathogens that could be transmitted among newly sympatric species to evaluate and anticipate their effects on bee communities. We used PCR screening and DNA sequencing to evaluate exposure to potentially disease-causing microorganisms in a pollinator of apple, the horned mason bee (Osmia cornifrons). We did not detect microsporidia, Wolbachia, or trypanosomes, which are common pathogens of bees, in any of the hundreds of mason bees screened. We did detect both pathogenic and apathogenic (saprophytic) fungal species in the genus Ascosphaera (chalkbrood), an unidentified species of Aspergillus fungus, and a strain of bacteria in the genus Paenibacillus that is probably apathogenic. We detected pathogenic fungal strains in asymptomatic adult bees that therefore may be carriers of disease. We demonstrate that fungi from the genus Ascosphaera have been transported to North America along with the bee from its native range in Japan, and that O. cornifrons is exposed to fungi previously only identified from nests of other related bee species. Further study will be required to quantify pathogenicity and health effects of these different microbial species on O. cornifrons and on closelyrelated native North American mason bees that may now be exposed to novel pathogens. A global perspective is required for pathogen research as geographic ranges of insects and microorganisms shift due to intentional or accidental introductions. Copyright:


This research was supported by an Academic Venture Fund grant from the David R. Atkinson Center for a Sustainable Future ( to BND as well as USDA National Institute of Food and Agriculture, Hatch project NYC-139415 (accession number 0230813) to BND. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the National Institute of Food and Agriculture (NIFA) or the United States Department of Agriculture (USDA). SMH was supported in part by funding from the Cornell Center for Comparative and Population Genomics ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.


Publication Date



PLoS One





Article Number

ARTN e0130560




Public Library of Science



Rights Statement

© 2015 Hedtke et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.