Bumblebees can be Exposed to the Herbicide Glyphosate when Foraging

Area of Science:

• Environmental Toxicology
• Pollinator Health
• Pesticide Impact

Background:

• Herbicides are widely used pesticides globally.
• Potential risks of herbicides to bee health remain a concern.
• Understanding bee exposure routes to herbicides is crucial.

Purpose of the Study:

• To determine if bumblebees forage on glyphosate-treated plants.
• To assess glyphosate residue presence in pollen collected by bees.
• To investigate the availability of floral resources post-herbicide treatment.

Main Methods:

• Choice test to observe bumblebee foraging behavior on treated and control plants.
• Analysis of pollen for glyphosate and aminomethylphosphonic acid residues.
• Assessment of nectar and pollen availability in treated plants.

Main Results:

• Bees did not avoid foraging on glyphosate-treated plants.
• Floral resources remained available for at least 5 days post-treatment.
• Glyphosate residues were detected in pollen up to 70 hours post-treatment.

Conclusions:

• Bees can be exposed to herbicides orally and topically by foraging on treated plants before plant death.
• This foraging behavior represents a significant exposure pathway for bees.
• Further research is needed to assess the full impact of herbicides on bee health and pollinating insects.