Pesticide exposure patterns in honey bees during migratory pollination

Area of Science:

• Agricultural Science
• Environmental Toxicology
• Pollinator Health

Background:

• Pesticide exposure monitoring is crucial for protecting honey bees.
• Commercial migratory beekeeping exposes colonies to diverse agricultural landscapes.

Purpose of the Study:

• To investigate pesticide exposure patterns in honey bee colonies during migratory pollination.
• To assess risks to honey bees from pesticide residues in bee bread and identify impacts on colony health.

Main Methods:

• Monitoring pesticide residues in bee bread from colonies during pollination events.
• Assessing exposure risk using the risk quotient (RQ) model.
• Observing colony health, including brood mortality, in relation to pesticide exposure.

Main Results:

• Pesticide exposures varied seasonally, with increased fungicide exposure during almond bloom and higher insecticide/fungicide exposure during fruit pollination.
• Risk quotient analysis indicated no acute toxicity risk to adult bees.
• Severe brood mortality was observed in fields with high exposure to buprofezin, an insect growth regulator.

Conclusions:

• Current risk assessments may not fully capture the impact of certain pesticides, like insect growth regulators, on immature bees.
• Improved compliance with insecticide label requirements during tree fruit pollination is needed.
• Further research on insect growth regulator impacts on honey bee larvae is essential for policy development.