マルハナバチのスーパーフードに隠された驚くべき科学的事実が明らかに。(UMass Amherst Research Finds Surprising Science Behind Bumblebee Superfood)

ヒマワリ科のトゲトゲ花粉がマルハナバチの広域寄生虫の有病率を大幅に減少、女王蜂の生産量も増加 Sunflower family’s spiny pollen vastly reduces prevalence of widespread parasite in bumblebees, increases production of queens

2023-04-05 マサチューセッツ大学アマースト校

Smooth pollen from buckwheat (A) and red maple (B), and spiny pollen from plants in the sunflower family (C-J). Credit: Figueroa et al., 10.1111/1365-2435.14320

<関連情報>

• https://www.umass.edu/news/article/umass-amherst-research-finds-surprising-science-behind-bumblebee-superfood
• https://royalsocietypublishing.org/doi/10.1098/rspb.2023.0055
• https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2435.14320

ヒマワリの植栽により、一般的な腸内病原体が減少し、ヒガシマルハナバチのコロニーにおける女王蜂の生産量が増加した。 Sunflower plantings reduce a common gut pathogen and increase queen production in common eastern bumblebee colonies

Rosemary L. Malfi,Quinn S. McFrederick,Giselle Lozano,Rebecca E. Irwin and Lynn S. Adler
Proceedings of the Royal Society B: Biological Sciences  Published:05 April 2023
DOI:https://doi.org/10.1098/rspb.2023.0055

Abstract

Community diversity can reduce the prevalence and spread of disease, but certain species may play a disproportionate role in diluting or amplifying pathogens. Flowers act as both sources of nutrition and sites of pathogen transmission, but the effects of specific plant species in shaping bee disease dynamics are not well understood. We evaluated whether plantings of sunflower (Helianthus annuus), whose pollen reduces infection by some pathogens when fed to bees in captivity, lowered pathogen levels and increased reproduction in free-foraging bumblebee colonies (Bombus impatiens). Sunflower abundance reduced the prevalence of a common gut pathogen, Crithidia bombi, and reduced infection intensity, with an order of magnitude lower infection intensity at high sunflower sites compared with sites with little to no sunflower. Sunflower abundance was also positively associated with greater queen production in colonies. Sunflower did not affect prevalence of other detected pathogens. This work demonstrates that a single plant species can drive disease dynamics in foraging B. impatiens, and that sunflower plantings can be used as a tool for mitigating a prevalent pathogen while also increasing reproduction of an agriculturally important bee species.

ヒマワリのトゲとその先: ヒガシマルハナバチにおける腸内病原体感染を軽減する花粉のメカニズムとその幅 Sunflower spines and beyond: Mechanisms and breadth of pollen that reduce gut pathogen infection in the common eastern bumble bee

Laura L. Figueroa, Alison Fowler, Stephanie Lopez, Victoria E. Amaral, Hauke Koch, Philip C. Stevenson, Rebecca E. Irwin, Lynn S. Adler
Functional Ecology  Published: 19 March 2023
DOI:https://doi.org/10.1111/1365-2435.14320

Abstract

1. 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 pathogen Crithidia 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.
2. 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.
3. 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 C. bombi infections than those fed non-Asteraceae pollen. Spine length, however, did not explain variation in bumble bee infection.
4. Our study indicates that sunflower pollen’s capacity to suppress 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.

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