Bee swimming is adaptive but disrupted by insecticide

Area of Science:

• Ecology
• Entomology
• Behavioral Biology

Background:

• Honey bees (Apis mellifera L.) exhibit a unique water-walking locomotion, propelling themselves on water surfaces while keeping wings dry.
• The ecological significance of this hydrofoiling behavior in bees remained unclear.

Purpose of the Study:

• To investigate the ecological relevance of water-walking locomotion in bees.
• To determine the effect of neonicotinoid insecticides on this behavior.
• To compare water-walking behavior across different bee species.

Main Methods:

• Observed honey bee and mason bee (Osmia excavata) behavior on water surfaces.
• Assessed preference for dark areas (skototaxis) during water locomotion.
• Tested the impact of thiamethoxam insecticide on honey bee motor control and skototaxis.
• Compared swimming efficiency between male and female mason bees.

Main Results:

• Honey bees demonstrated skototaxis, preferring dark regions when moving on water.
• Thiamethoxam disrupted honey bee skototaxis by impairing motor control.
• Mason bees also exhibited skototaxis, with a stronger preference for dark areas than honey bees.
• Female mason bees were more efficient swimmers than males.

Conclusions:

• Water-walking behavior in bees is an ancient trait, predating sociality, with significant adaptive and ecological functions.
• Environmental pollutants, such as pesticides, can negatively affect this essential bee behavior.
• Skototaxis is a key component of water locomotion in bees, with species-specific variations.