The world’s most widely used insecticides harm the ability of bees to vibrate flowers and shake out the pollen to fertilise crops, according to preliminary results from a new study.
Some flowers, such as those of crops like tomatoes and potatoes, must be shaken to release pollen and bumblebees are particularly good at creating the buzz needed to do this. But the research shows that bumblebees exposed to realistic levels of a neonicotinoid pesticide fail to learn how to create the greatest buzz and collect less pollen as a result.
The research is consistent with previous work that has shown neonicotinoid pesticides reduce learning and memory in bees. A moratorium on the use of three neonicotinoids on flowering crops was put in place in Europe in 2013 and will be reviewed next year.
In many flowers, bees collect pollen by simply brushing it off the anthers (the part of the stamen that contains the pollen), but other flowers require more work.
“So bees produce a vibration – or buzz – to shake pollen out of these anthers like a pepper pot,” said Penelope Whitehorn of the University of Stirling in Scotland, who led the study. “The bee lands on a flower, curls her body around the anther and grips the base with her mandibles. She then rapidly contracts the flight muscles to produce the vibration, without beating her wings.”
The researchers took two colonies of bumblebees in a laboratory setting and split the bees in each into three groups. One control group was not exposed to the neonicotinoid thiamethoxam, but the other two groups were fed solutions containing two parts per billion or 10ppb of the pesticide, doses similar to those found in crop fields.
After each visit to the buffalo-bur flowers used in the experiment, the bees in the control group learned how to buzz more pollen out of the anthers. But those in the 10ppb group did not improve at all.
Whitehorn will present the preliminary results at the British Ecological Society’s annual meeting on Tuesday and said they were “striking” and statistically significant, and would be submitted to a scientific journal next year.
“The implication is the bees take less pollen back to the colonies and the colonies will be less successful, meaning there may be fewer pollinators overall,” she said.
The study adds to a large body of evidence from lab- and field-based studies that neonicotinoids reduce learning and memory in bees, impair their communication, foraging efficiency and immune systems and, crucially, reduce their reproductive success as well as the pollination services that they can provide, Whitehorn said.
“These chemicals do have serious implications for wild bee populations in agricultural landscapes but some, notably from the agrochemical industry, still promote their use,” she warned.
A spokesman for Syngenta, which manufactures thiamethoxam, said: “Crop-measured pollen and nectar residues from thiamethoxam seed-treated oilseed rape is typically less than 3ppb. In all our thiamethoxam seed-treated oilseed rape field studies we have never recorded a pollen or nectar residue as high as 10ppb.”
There is strong evidence that neonicotinoids harm individual bees but only a little evidence to date that this harms colonies. Bees and other pollinators fertilise about three-quarters of the world’s food crops and have seen widespread declines due to habitat loss, disease and pesticide use.
This article was first published by The Guardian on 13 Dec 2016.
We invite you to share your opinion whether neonicotinoid pesticides should be banned to save our bees? Please vote and leave your comments at the bottom of this page:
Thank you for voting.
Share on social media:
You may also like:
Top-Viewed Posts Last 30 Days
- POLL: Should the cruel sport of bullfighting be banned? [2799 Views]
- POLL: Should South Africa’s canned hunting industry be banned? [1883 Views]
- POLL: Should Mozambique’s wildlife park be funded by trophy hunting? [1392 Views]
- POLL: Should the use of elephants for “entertainment” be banned? [1217 Views]
- POLL: Should Asia’s elephant tourism be banned? [968 Views]
- Bald Eagle Adopts Baby Hawk Instead of Eating Him [911 Views]
- POLL: Should wildlife-killing “cyanide bombs” be banned? [897 Views]
- POLL: Should the use of wild animals in circuses be banned? [880 Views]
- POLL: Should Yellowstone Grizzlies be removed from the Endangered List? [859 Views]
- POLL: Should the owning of exotic pets be banned? [745 Views]
Top-Viewed Posts Last 12 Months
- POLL: Should there be a worldwide ban on fur farms? [16900 Views]
- POLL: Should Congress disband Wildlife “Killing” Services? [11095 Views]
- Gray Squirrels versus Red Squirrels – The Facts [10111 Views]
- POLL: Should driven grouse-shooting be banned? [8689 Views]
- POLL: Should grouse shooting on highland estates be banned? [8233 Views]
- POLL: Should the killing of giraffes be outlawed? [4711 Views]
- POLL: Should the sale of elephant ivory be legalized? [4081 Views]
- POLL: Should foxes be culled to protect domestic pets? [3771 Views]
- POLL: Should the coyote continue to be exterminated? [3448 Views]
- POLL: Should the use of snares be banned in the UK? [2609 Views]