Commonly Used Pesticide Turns Honey Bees into 'Picky Eaters'

Summary

Since 2006, honeybee populations have faced alarming declines, with beekeepers in North America and Europe losing about a third of their colonies. Researchers at UC San Diego have identified a possible contributor: the pesticide imidacloprid. Experiments showed that even small doses make bees picky eaters, preferring only the sweetest nectar, and reduce their ability to communicate food sources to nestmates. These behavioral changes limit food availability in the hive, threatening colony survival. The findings highlight a potential cause of colony collapse disorder and underscore the need for careful pesticide use, particularly in bee-pollinated crops.

Takeaways

• 🐝 Since 2006, honey bees in North America and Europe have experienced dramatic population declines, with beekeepers losing about a third of managed colonies.
• 🔍 The exact cause of these declines is not fully known, but scientists are investigating potential factors.
• ⚠️ UC San Diego biologists identified a possible culprit: colony collapse disorder linked to pesticides.
• 🌿 A commonly used pesticide called imidacloprid, applied on crops and in gardens, may negatively affect bees' feeding behavior.
• 🍯 Bees exposed to small doses of imidacloprid become picky eaters, preferring only the sweetest sugar water and ignoring lower-concentration nectar.
• 📉 This selective feeding reduces the food available in the hive, potentially impacting colony survival and health.
• 🗣️ Pesticide-exposed bees are less active in communicating food sources to nestmates, sometimes stopping the communication entirely.
• 💃 The waggle dance is the method bees use to share food location information with their colony members.
• 🌍 Some European countries have banned imidacloprid for certain crops due to its harmful effects on bees.
• 📚 These findings have broader implications for how pesticides are applied, highlighting the need for careful management in pollinator-dependent crops.
• 🔬 Research like this helps scientists understand and mitigate factors contributing to colony collapse disorder.

Q & A

What phenomenon has caused significant losses in honeybee populations since 2006?

Honeybee populations have experienced dramatic declines due to a phenomenon known as colony collapse disorder.

Approximately what fraction of managed honeybee colonies have been lost in North America and Europe?

Beekeepers have lost about one-third of their managed colonies.

What potential culprit have UC San Diego biologists identified for honeybee decline?

They identified a small dose of a commonly used crop pesticide, imidacloprid, as a possible contributor to colony collapse disorder.

How does imidacloprid affect honeybee feeding behavior?

Imidacloprid makes honeybees picky eaters, causing them to prefer only the sweetest nectar and ignore lower concentrations of sugar water that would normally feed their colony.

What impact does the pesticide have on honeybee communication?

Bees exposed to the pesticide are less active in communicating the location of food sources to nestmates, and in some cases, they stop communicating altogether.

What is the significance of the waggle dance in honeybees?

The waggle dance is a method bees use to communicate the location of food sources to their nestmates.

Where was the research on pesticide effects on bees conducted?

The research was conducted at the UC San Diego Biological Field Station.

What experimental method did researchers use to test bees’ food preferences?

Researchers individually harnessed bees so that only their heads could move and tested their response to sugar water concentrations from 0 to 50% by touching their antennae to see if they extended their mouthparts.

Why is the finding about pesticide effects on honeybees important for agriculture?

It has implications for how pesticides are applied and used on bee-pollinated crops, as improper use could worsen colony collapse disorder.

Has imidacloprid been regulated differently in other parts of the world?

Yes, it has been banned in some European countries for use on certain crops due to its harmful effects on bees.

What is the broader consequence of bees becoming picky eaters due to pesticide exposure?

With fewer bees gathering food and failing to communicate effectively, the hive receives less nourishment, leading to lower survival and thriving rates for the colony.