title: Introduction of Non-Native Pollinators Can Lead to Trans-Continental Movement of Bee-Associated Fungi.
abstract: 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 closely-related 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.
authors.affiliation: Department of Entomology, Cornell University, Ithaca, New York, United States of America; Department of Ecology, Environment, and Evolution, La Trobe University, Bundoora, Victoria, Australia.
authors.forename: Shannon M
authors.initials: SM
authors.lastname: Hedtke
authors.affiliation: Department of Entomology, Cornell University, Ithaca, New York, United States of America.
authors.forename: Eleanor J
authors.initials: EJ
authors.lastname: Blitzer
authors.affiliation: Department of Entomology, Cornell University, Ithaca, New York, United States of America.
authors.forename: Graham A
authors.initials: GA
authors.lastname: Montgomery
authors.affiliation: Department of Entomology, Cornell University, Ithaca, New York, United States of America.
authors.forename: Bryan N
authors.initials: BN
authors.lastname: Danforth
mesh_terms: D025041:Animal Migration; D000818:Animals; D001230:Aspergillus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D001516:Bees / Q000145:classification / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis; D004271:DNA, Fungal / Q000032:analysis; D005260:Female; D054884:Host-Pathogen Interactions; D007306:Insecticides; D058865:Introduced Species; D007564:Japan; D016013:Likelihood Functions; D008297:Male; D027845:Malus; D008969:Molecular Sequence Data; D009425:Nesting Behavior; D009518:New York; D020036:Onygenales / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D056507:Paenibacillus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D010802:Phylogeny; D054817:Pollination; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D004269:DNA, Bacterial; D004271:DNA, Fungal; D007306:Insecticides