2026-04-03 バージニア工科大学（VirginiaTech）
米バージニア工科大学の研究により、除草剤グリホサートがミツバチの健康に与える影響が明らかになった。曝露により腸内細菌叢のバランスが乱れ、免疫機能や栄養吸収に悪影響を及ぼす可能性が示された。さらに行動変化や生存率低下にも関連し、コロニー全体の健全性に影響を与えることが示唆された。
本研究は、農業で広く使用される化学物質が受粉昆虫に与えるリスクを再評価する必要性を示し、持続可能な農業や生態系保全の観点から重要な知見を提供する。今後は曝露量の管理や代替手法の検討が求められる。
A marked honeybee drinks a sugar solution containing glyphosate from a feeder. Photo by Margaret Couvillon for Virginia Tech.
＜関連情報＞
- https://news.vt.edu/articles/2026/03/cals-honeybee-glyphosate-impact.html
- https://journals.biologists.com/jeb/article-abstract/228/9/jeb250124/367891/Sublethal-glyphosate-exposure-reduces-honey-bee?redirectedFrom=fulltext
致死量以下のグリホサートへの曝露はミツバチの採餌活動を減少させ、脳内の生体アミンのバランスを変化させる Sublethal glyphosate exposure reduces honey bee foraging and alters the balance of biogenic amines in the brain
Laura C. McHenry,Roger Schürch,McAlister Council-Troche,Aaron D. Gross,Lindsay E. Johnson,Bradley D. Ohlinger,Margaret J. Couvillon
Journal of Experimental Biology Published:06 May 2025
DOI:https://doi.org/10.1242/jeb.250124
ABSTRACT
Glyphosate is a broad-spectrum herbicide that inhibits the shikimate pathway, which honey bees (Apis mellifera), a non-target beneficial pollinator, do not endogenously express. Nonetheless, sublethal glyphosate exposure in honey bees has been correlated to impairments in gustation, learning, memory and navigation. While these impacted physiologies underpin honey bee foraging and recruitment, the effects of sublethal glyphosate exposure on these important behaviors remain unclear, and any proximate mechanism of action in the honey bee is poorly understood. We trained cohorts of honey bees from the same hives to forage at one of two artificial feeders offering 1 mol l−1 sucrose solution, either unaltered (N=40) or containing glyphosate at 5 mg acid equivalent (a.e.) l−1 (N=46). We then compared key foraging behaviors and, on a smaller subset of bees, recruitment behaviors. Next, we quantified protein levels of octopamine, tyramine and dopamine, and levels of the amino acid precursor tyrosine in the brains of experimental bees collected 3 days after the exposure. We found that glyphosate treatment bees reduced their foraging by 13.4% (P=0.022), and the brain content of tyramine was modulated by a crossover interaction between glyphosate treatment and the number of feeder visits (P=0.004). Levels of octopamine were significantly correlated with its precursors tyramine (P=0.011) and tyrosine (P=0.018) in glyphosate treatment bees, but not in control bees. Our findings emphasize the critical need to investigate impacts of the world’s most-applied herbicide and to elucidate its non-target mechanism of action in insects to create better-informed pollinator protection strategies.
