Sublethal imidacloprid effects on honey bee flower choices when foraging

Area of Science:

• Agricultural Science
• Ecology
• Entomology

Background:

• Neonicotinoids are widely used pesticides linked to honey bee decline.
• Imidacloprid, a common neonicotinoid, is investigated for its sublethal effects on bee behavior.

Purpose of the Study:

• To assess the impact of imidacloprid on the foraging behavior of honey bees (Apis mellifera anatoliaca).
• To determine if imidacloprid affects honey bee return rates, foraging trip frequency, and floral reward choice.

Main Methods:

• Free-flying honey bees were orally administered varying doses of imidacloprid (1/5 to 1/50 LD50).
• Bees foraged on artificial flowers offering different sucrose concentrations, with rewards reversed between blue and white flowers across trials.
• Forager return rate, visitation frequency, and flower choice were recorded post-treatment.

Main Results:

• Forager return rate decreased linearly with increasing imidacloprid dosage.
• The number of foraging trips per bee was negatively affected by imidacloprid.
• Flower fidelity was not dose-dependent, and bees accurately selected higher sugar rewards.

Conclusions:

• Imidacloprid exhibits acute, mild effects on honey bee foraging behavior.
• Bees retain the ability to discern and select higher nectar rewards even after pesticide exposure.
• The findings suggest the potential for imidacloprid contamination in honey, posing risks to bee colonies.