Pathogen 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 (
1. Social insect castes and sexes differ in many ways, including morphology, behavior, and sometimes ploidy level. Recent studies have found that consuming sunflower pollen reduces the gut pathogen
2. This study examined the effect of sunflower pollen compared to a diverse wildflower pollen mix on infection in worker, male, and daughter queen commercial
3. Compared to wildflower pollen, sunflower pollen dramatically reduced
4. Reducing
- NSF-PAR ID:
- 10452874
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Ecological Entomology
- Volume:
- 45
- Issue:
- 6
- ISSN:
- 0307-6946
- Page Range / eLocation ID:
- p. 1318-1326
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Helianthus annuus ) 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. bombi infection prevalence and intensity within individualB. impatiens workers 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. bombi infection 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. -
Abstract Plants have unique chemical and physical traits that can reduce infections in animals ranging from primates to caterpillars. Sunflowers (
Helianthus annuus ; Asteraceae) are one striking example, with pollen that suppresses infections by the trypanosomatid gut pathogenCrithidia bombi in the common eastern bumble bee (Bombus impatiens ). However, the mechanism underlying this effect has remained elusive, and we do not know whether pollens from other Asteraceae species have similar effects.We evaluated whether mechanisms mediating sunflower pollen's antipathogenic effects are physical (due to its spiny exine), chemical (due to metabolites) or both. We also evaluated the degree to which pollen from seven other Asteraceae species reduced
C. bombi infection relative to pollen from sunflower and two non‐Asteraceae species, and whether pollen spine length predicted pathogen suppression.We found that sunflower exines alone reduced infection as effectively as whole sunflower pollen, while sunflower pollen metabolites did not. Furthermore, bees fed pollen from four of seven other Asteraceae had 62%–92% lower
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C. bombi is driven by its spiny exine, and that this phenomenon extends to several other Asteraceae species. Our results indicate that sunflower pollen exines are as effective as whole pollen in reducing infection, suggesting that future studies should expand to assess the effects of other species with spiny pollen on pollinator–pathogen dynamics.Read the free
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Abstract Global 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 (
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