@article{strange_tripodi_huntzinger_knoblett_klinger_herndon_vuong_mcfrederick_irwin_evans_et al._2023, title={Comparative analysis of 3 pollen sterilization methods for feeding bumble bees}, volume={116}, ISSN={0022-0493 1938-291X}, url={http://dx.doi.org/10.1093/jee/toad036}, DOI={10.1093/jee/toad036}, abstractNote={Abstract
               Pollen is an essential component of bee diets, and rearing bumble bees (Bombus spp.) for commercial use necessitates feeding pollen in mass quantities. This pollen is collected from honey bee (Apis mellifera L.) colonies because neither an artificial diet nor an economical, large-scale pollen collection process from flowers is available. The provenance of honey bee-collected pollen is often unknown, and in some cases has crossed international borders. Both deformed wing virus (DWV) and the fungal pathogen Ascosphaera apis (Claussen) Olive & Spiltoir (cause of chalkbrood disease); occur in honey bee-collected pollen, and infections have been observed in bumble bees. We used these pathogens as general surrogates for viruses and spore-forming fungal diseases to test the efficacy of 3 sterilization methods, and assessed whether treatment altered pollen quality for the bumble bee. Using honey bee-collected pollen spiked with known doses of DWV and A. apis, we compared gamma irradiation (GI), ozone fumigation (OZ), and ethylene oxide fumigation (EO) against an untreated positive control and a negative control. Following sterilization treatments, we tested A. apis spore viability, detected viral presence with PCR, and tested palatability to the bumble bee Bombus impatiens Cresson. We also measured bacterial growth from pollens treated with EO and GI. GI and EO outperformed OZ treatment in pathogen suppression. EO had the highest sterilizing properties under commercial conditions and retained palatability and supported bee development better than other treatments. These results suggest that EO sterilization reduces pathogen risks while retaining pollen quality as a food source for rearing bumble bees.}, number={3}, journal={Journal of Economic Entomology}, publisher={Oxford University Press (OUP)}, author={Strange, James P and Tripodi, Amber D and Huntzinger, Craig and Knoblett, Joyce and Klinger, Ellen and Herndon, James D and Vuong, Hoang Q and McFrederick, Quinn S and Irwin, Rebecca E and Evans, Jay D and et al.}, editor={Tarpy, DavidEditor}, year={2023}, month={Mar}, pages={662–673} }
 @article{giacomini_adler_reading_irwin_2023, title={Differential bumble bee gene expression associated with pathogen infection and pollen diet}, volume={24}, ISSN={1471-2164}, url={http://dx.doi.org/10.1186/s12864-023-09143-5}, DOI={10.1186/s12864-023-09143-5}, abstractNote={Abstract
                Background
                Diet and parasitism can have powerful effects on host gene expression. However, how specific dietary components affect host gene expression that could feed back to affect parasitism is relatively unexplored in many wild species. Recently, it was discovered that consumption of sunflower (Helianthus annuus) pollen reduced severity of gut protozoan pathogen Crithidia bombi infection in Bombus impatiens bumble bees. Despite the dramatic and consistent medicinal effect of sunflower pollen, very little is known about the mechanism(s) underlying this effect. However, sunflower pollen extract increases rather than suppresses C. bombi growth in vitro, suggesting that sunflower pollen reduces C. bombi infection indirectly via changes in the host. Here, we analyzed whole transcriptomes of B. impatiens workers to characterize the physiological response to sunflower pollen consumption and C. bombi infection to isolate the mechanisms underlying the medicinal effect. B. impatiens workers were inoculated with either C. bombi cells (infected) or a sham control (un-infected) and fed either sunflower or wildflower pollen ad libitum. Whole abdominal gene expression profiles were then sequenced with Illumina NextSeq 500 technology.
              
                Results
                Among infected bees, sunflower pollen upregulated immune transcripts, including the anti-microbial peptide hymenoptaecin, Toll receptors and serine proteases. In both infected and un-infected bees, sunflower pollen upregulated putative detoxification transcripts and transcripts associated with the repair and maintenance of gut epithelial cells. Among wildflower-fed bees, infected bees downregulated immune transcripts associated with phagocytosis and the phenoloxidase cascade.
              
                Conclusions
                Taken together, these results indicate dissimilar immune responses between sunflower- and wildflower-fed bumble bees infected with C. bombi, a response to physical damage to gut epithelial cells caused by sunflower pollen, and a strong detoxification response to sunflower pollen consumption. Identifying host responses that drive the medicinal effect of sunflower pollen in infected bumble bees may broaden our understanding of plant-pollinator interactions and provide opportunities for effective management of bee pathogens.

              }, number={1}, journal={BMC Genomics}, publisher={Springer Science and Business Media LLC}, author={Giacomini, Jonathan J. and Adler, Lynn S. and Reading, Benjamin J. and Irwin, Rebecca E.}, year={2023}, month={Mar} }
 @article{giacomini_moore_adler_irwin_2022, title={Sunflower pollen induces rapid excretion in bumble bees: Implications for host-pathogen interactions}, volume={137}, ISSN={0022-1910}, url={http://dx.doi.org/10.1016/j.jinsphys.2022.104356}, DOI={10.1016/j.jinsphys.2022.104356}, abstractNote={Host diet can have a profound effect on host-pathogen interactions, including indirect effects on pathogens mediated through host physiology. In bumble bees (Bombus impatiens), the consumption of sunflower (Helianthus annuus) pollen dramatically reduces infection by the gut protozoan pathogen Crithidia bombi. One hypothesis for the medicinal effect of sunflower pollen is that consumption changes host gut physiological function, causing rapid excretion that flushes C. bombi from the system. We tested the effect of pollen diet and C. bombi infection on gut transit properties using a 2x2 factorial experiment in which bees were infected with C. bombi or not and fed sunflower or wildflower pollen diet. We measured several non-mutually exclusive physiological processes that underlie the insect excretory system, including gut transit time, bi-hourly excretion rate, the total number of excretion events and the total volume of excrement. Sunflower pollen significantly reduced gut transit time in uninfected bees, and increased the total number of excretion events and volume of excrement by 66 % and 68 %, respectively, in both infected and uninfected bees. Here we show that a sunflower pollen diet can affect host physiology gut function, causing more rapid and greater excretion. These results provide important insight into a mechanism that could underlie the medicinal effect of sunflower pollen for bumble bees.}, journal={Journal of Insect Physiology}, publisher={Elsevier BV}, author={Giacomini, Jonathan J. and Moore, Nicholas and Adler, Lynn S. and Irwin, Rebecca E.}, year={2022}, month={Feb}, pages={104356} }
 @article{fowler_giacomini_connon_irwin_adler_2022, title={Sunflower pollen reduces a gut pathogen in the model bee species,
            <i>Bombus impatiens
            , but has weaker effects in three wild congeners}, volume={289}, ISSN={0962-8452 1471-2954}, url={http://dx.doi.org/10.1098/rspb.2021.1909}, DOI={10.1098/rspb.2021.1909}, abstractNote={
            Commercial bumblebees have become popular models to understand stressors and solutions for pollinator health, but few studies test whether results translate to other pollinators. Consuming sunflower pollen dramatically reduces infection by the gut parasite
            Crithidia bombi
            in commercially reared
            Bombus impatiens
            . We assessed the effect of sunflower pollen on infection in wild
            B. impatiens
            ,
            Bombus griseocollis, Bombus bimaculatus
            and
            Bombus vagans
            . We also asked how pollen diet (50% sunflower pollen versus wildflower pollen) and infection (yes/no) affected performance in wild
            B. impatiens
            microcolonies. Compared to controls, sunflower pollen dramatically reduced
            Crithidia
            infection in commercial and wild
            B. impatiens,
            had similar but less dramatic effects in
            B. bimaculatus
            and
            B. vagans
            , and no effect in
            B. griseocollis
            .
            Bombus impatiens, B. bimaculatus
            and
            B. vagans
            are in the same subgenus, suggesting that responses to sunflower pollen may be phylogenetically conserved. In microcolonies, 50% sunflower pollen reduced infection compared to wildflower pollen, but also reduced reproduction. Sunflower pollen could control
            Crithidia
            infections in
            B. impatiens
            and potentially close relatives, but may hinder reproduction if other resources are scarce. We caution that research using managed bee species, such as
            B. impatiens
            , be interpreted carefully as findings may not relate to all bee species.
          }, number={1968}, journal={Proceedings of the Royal Society B: Biological Sciences}, publisher={The Royal Society}, author={Fowler, Alison E. and Giacomini, Jonathan J. and Connon, Sara June and Irwin, Rebecca E. and Adler, Lynn S.}, year={2022}, month={Feb} }
 @article{giacomini_connon_marulanda_adler_irwin_2021, title={The costs and benefits of sunflower pollen diet on bumble bee colony disease and health}, volume={12}, ISSN={2150-8925 2150-8925}, url={http://dx.doi.org/10.1002/ecs2.3663}, DOI={10.1002/ecs2.3663}, abstractNote={AbstractPathogen transmission between domesticated and wild host species has important implications for community ecology, agriculture, and wildlife conservation. Bumble bees provide valuable pollination services that are vital for both wildflowers and agricultural production. Intense concerns about pathogen spillover from commercial bumble bees to wild bee populations, and the potential harmful effects of pathogen spillback to commercial bees, has stimulated a need for practical strategies that effectively manage bumble bee infectious diseases. Here, we assessed the costs and benefits of a medicinal sunflower pollen diet (Helianthusannuus) on whole‐colony bumble bee disease and performance using commercial colonies of the common eastern bumble bee,Bombus impatiens, and its protozoan pathogen,Crithidia bombi(Trypanosomatida). We first found that a 1:1 mixture of sunflower combined with wildflower pollen reducedC. bombiinfection prevalence and intensity within individualB. impatiensworkers by nearly 4‐fold and 12‐fold, respectively, relative to wildflower pollen. At the colony level, a 1:1 mixture of sunflower and wildflower pollen reducedC. bombiinfection prevalence by 11% averaged over a 10‐week period and infection intensity by 30% relative to wildflower pollen. Colony performance was similar between pollen diets and infection treatments, including the number of workers and immatures produced, and size and weight of workers, drones, and queens. Infection significantly reduced the probability of queen production in colonies fed a pure wildflower pollen diet, but not colonies fed a mixed sunflower pollen diet, suggesting that the medicinal benefits of a mixed sunflower pollen diet can reverse the negative effects of infection on reproductive success. This study provides evidence that sunflower pollen as part of a mixed pollen diet can reduce infection in individual bees and whole colonies with no significant nutritional trade‐offs for colony worker production and most aspects of colony reproduction. A supplemental mixed sunflower pollen diet may provide a simple and effective solution to reduce disease and improve the health of economically and ecologically important pollinators.}, number={7}, journal={Ecosphere}, publisher={Wiley}, author={Giacomini, Jonathan J. and Connon, Sara J. and Marulanda, Daniel and Adler, Lynn S. and Irwin, Rebecca E.}, year={2021}, month={Jul} }
 @article{giacomini_leslie_tarpy_palmer-young_irwin_adler_2018, title={Medicinal value of sunflower pollen against bee pathogens}, volume={8}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/s41598-018-32681-y}, DOI={10.1038/s41598-018-32681-y}, abstractNote={AbstractGlobal declines in pollinators, including bees, can have major consequences for ecosystem services. Bees are dominant pollinators, making it imperative to mitigate declines. Pathogens are strongly implicated in the decline of native and honey bees. Diet affects bee immune responses, suggesting the potential for floral resources to provide natural resistance to pathogens. We discovered that sunflower (Helianthus annuus) pollen dramatically and consistently reduced a protozoan pathogen (Crithidia bombi) infection in bumble bees (Bombus impatiens) and also reduced a microsporidian pathogen (Nosema ceranae) of the European honey bee (Apis mellifera), indicating the potential for broad anti-parasitic effects. In a field survey, bumble bees from farms with more sunflower area had lower Crithidia infection rates. Given consistent effects of sunflower in reducing pathogens, planting sunflower in agroecosystems and native habitat may provide a simple solution to reduce disease and improve the health of economically and ecologically important pollinators.}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Giacomini, Jonathan J. and Leslie, Jessica and Tarpy, David R. and Palmer-Young, Evan C. and Irwin, Rebecca E. and Adler, Lynn S.}, year={2018}, month={Sep} }