Honeybees Can Swim and Navigate Using Dark Visual Cues, Study Finds

When a bee crashes into water, it may still be able to swim to safety. New research confirms that honeybees can propel themselves across the water’s surface, and their movement is purposeful and directional, orienting toward darker areas to locate the shoreline and escape.

How Bees Swim

Scientists recently discovered that honeybees can propel themselves across water, a surprising ability for an insect built for flight. The mechanism behind this is surprisingly simple: the undersides of their wings become wet and lose lift, but the flight motor continues to fire, creating a hydrofoil-like effect. This generates waves that propel the bee forward. Research published in PNAS details how honeybees utilize their wings as hydrofoils for water surface locomotion.

Directional Swimming: The Role of Dark Cues

Bees don’t move randomly when on water; they actively orient toward darker areas, likely representing land, vegetation, or the edge of a pool. This behavior, known as skototaxis, is the tendency to move toward darker visual cues and increases their chances of escaping the water. Researchers at Michigan State University found that bees consistently moved toward dark areas in a shallow bowl of water, demonstrating a clear directional preference.

Impact of Insecticides on Swimming Ability

Exposure to thiamethoxam, a commonly used insecticide, significantly affects a bee’s ability to navigate whereas on the water. Bees exposed to the insecticide no longer showed a preference for dark areas, instead moving randomly and taking longer routes to reach the edge. Further analysis revealed that insecticide exposure led to increased turns, suggesting reduced motor control rather than a loss of visual orientation. This suggests that insecticides can disrupt the motor coordination needed for this survival behavior.

Mason Bees and Evolutionary Origins

The study also examined mason bees, a solitary species. Both male and female mason bees exhibited a strong preference for dark areas, even more so than honeybees. Female mason bees reached the edge faster and traveled shorter distances. These findings suggest that the ability to move across water and orient toward escape routes may have evolved before the development of complex bee societies.

Why This Matters

Bees encounter water frequently while foraging, collecting water for hive temperature regulation, or accidentally landing on bodies of water. The ability to propel themselves toward the shoreline could be crucial for survival. Even a small fraction of worker bees encountering water makes this ability beneficial for the colony. The research also highlights how pesticides can affect bee behaviors that are not typically studied, such as swimming.

Key Takeaways

• Honeybees can swim by using their wings to create a hydrofoil effect.
• Bees navigate toward darker areas when on water, likely to find the shoreline.
• Insecticide exposure impairs a bee’s ability to swim and orient toward safety.
• This swimming behavior may have evolved early in bee evolution.

This study was published in Communications Biology.