Spying on bees reveals pesticides impair social behaviour

2018-11-09 14:05

A new study that allowed humans to spy on bumblebees inside their nests showed that pesticides can impair social behaviour, making it hard for bees to eat and rear their young, researchers said on Thursday.

Previous research has shown that the common class of pesticides known as neonicotinoids can harm bees' ability to forage outside the nest.

The latest findings add to long-standing concerns about these important pollinators' health.

Researchers tracked the changes in bees' behaviour by placing cameras inside 12 specially made boxes that contained one chamber for a nest and another chamber for foraging.

Some bees were exposed to concentrations of the neonicotinoid imidacloprid similar to that expected in the environment. Others were not.

They found the pesticide-exposed bees were less social in a variety of ways than control bees placed in similar boxes but not fed nectar that contained neonicotinoids.

"Exposure to the neurotoxic pesticide resulted in measurable changes in worker bee behavior within the nest," said the report in the journal Science.

"The workers were less active, less likely to feed and care for larvae, and more likely to be found towards the periphery of the nest."

The effects were particularly noticeable at night.

"Bees actually have a very strong circadian rhythm," said lead author James Crall, a postdoctoral fellow at Harvard University.

"So what we found was that, during the day, there was no statistically observable effect, but at night, we could see that they were crashing."

Experiments also showed that pesticide exposure made it more difficult for bees to regulate their body temperature, and to build a protective wax cap over the colony.

"Almost all of our control colonies built that cap," Crall said.

"And it seems to be totally wiped out in the pesticide-exposed colonies, so they lose this capacity to do this functional restructuring of the nest."

Researchers said their findings add to mounting evidence of the harm posed by neonicotinoid pesticides.

The European Union has voted to outlaw the use of three neonicotinoids – clothianidin, imidacloprid and thiamethoxam – in crop fields.

France has gone even further and banned these three neonicotinoids plus thiacloprid and acetamiprid, both outdoors and in greenhouses.

In recent years, bees have been mysteriously dying off from "colony collapse disorder", blamed partly on pesticides as well as mites, viruses, and fungi.

The United Nations has warned that 40% of the planet's insect pollinators, particularly bees and butterflies, risk global extinction, which would have serious implications for food production and ecosystem health.

KEEP UPDATED on the latest news by subscribing to our FREE newsletter.

- FOLLOW News24 on Twitter

Read more on:    insects

Join the conversation!

24.com encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.

Inside News24

Traffic Alerts
There are new stories on the homepage. Click here to see them.


Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.

Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.


Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.

Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.