Weed killers should be redesigned to save bumblebees

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A new study conducted by researchers from Royal Holloway concluded that weed killers, bought by many households across the country and used in agriculture, could easily be redesigned to adapt to bumblebees by changing ingredients and thus saving bee lives.

Ph.D. student, Ed Straw and master’s student Edward Carpentier, along with Professor Mark Brown, all from the Center for Ecology, Evolution and Behavior at the Department of Biological Sciences at Royal Holloway, investigated the effects of weed killers on bumblebees.

Their research showed that, after bees came in contact with certain known weed killers, sold under the Roundup brand, up to 96% of bees died within 24 hours, compared to other weed killers, such as which is Weedol that did not cause fatal damage.

The mortality rate of other weed brands is thought to be due to ingredients used in the weed remover itself, blocking the breathing holes and gas exchange system of the bees, essentially drowning them, and gelling the bees ’hair.

The research was conducted with a range of weed removers, including those that can be purchased in supermarkets and used exclusively by farmers.

During research, Weedol was found to be safe for bumblebees because it does not cause mortality. A number of other weed killers from the same company caused mortality.

This could be because, despite the fact that the main ingredient in these sprays is glyphosate, previously thought to be the most harmful to bees, it was not actually the cause of bumblebee death, but more other ingredients, known as co-formulants, causing mortality.

Lead author Ed Straw of Royal Holloway said: “Weed killers are not usually considered as dangerous to bees and therefore farmers are allowed to spray weed remover directly on flowering plants while the bees are visiting them.

“However, our research has shown that bees, if they come into direct contact like this, could be very deadly, depending on the weed remover used and its ingredients.”

Edward Carpentier, also from Royal Holloway, added: “Weed killers are the most commonly used type of pesticide in the world, and now we know they can be dangerous to bees. We need to re-evaluate how to use them in a way that won’t harm bees.”

“Our research has shown that manufacturers need to be more transparent on the list of ingredients, and they also need to look at what they use in their formulas which makes one weed spray safer than another.

“This is a huge problem for our pollinator friends, but it could be a very easy repair.”

Professor Mark Brown of the Department of Biological Sciences at Royal Holloway said: “Wild bees, like bumblebees, are key to wild flowers and crops – without them we would lose both biodiversity and food safety.

“It is worrying that wild bees are declining around the world, and although we still do not know exactly why, this kind of research brings us closer to understanding.

“This research shows that the indiscriminate use of weed killers in agricultural and urban areas could pose a real threat to bee health, but also that simple changes in the behavior and composition of weed killers could immediately eliminate this danger.”

Bumblebee larvae growth damaged by insecticide

More information:
Edward A. Straw et al. Examination causes a high mortality rate after exposure to contact in bumblebee bees, Journal of Applied Ecology (2021). DOI: 10.1111 / 1365-2664.13867

Provided by Royal Holloway, University of London

Citation: Weed killers need to be redesigned to save bumblebees (2021, April 8) downloaded April 8, 2021 from https://phys.org/news/2021-04-weed-killers-redesigned-bumblebees.html

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