World’s Most Common Pesticide Could Be Causing Bumblebees To Go Colorblind

There have been a lot of discussions on bumblebees in the past few years. Concerns over bees disappearing have cast a light on them in an unusual way, but there have also been some studies that show they can feel pain and another, which shines a light on a popular pesticide.

More than likely, you have used Roundup at some time in the past. It’s an herbicide that is used for killing weeds, but it seems as if it is also affecting bumblebees in a rather unusual way.

Photo: flickr/Mike Mozart

Considering the fact that flowering plants around the world require pollinators for their survival, it’s important that bumblebees are kept safe. In addition, bumblebees rely on seeing color in order to determine where to land and gather the pollen.

In an experiment, bumblebees were kept in an area with Roundup. That herbicide contains glyphosate, which has already been shown to affect temperature regulation when bee colonies are exposed to it. It seems as if it may also have an effect on a bumblebee’s ability to see color.

The bumblebees were given 10 tasks that involved color to see how the herbicide affected them. This included 20 artificial flowers, and two of each of the flowers would have a unique color.

Photo: flickr/Judy Gallagher

Five of the colors were associated with the type of sugar that would attract the bumblebee to the flower in the first place. The other five were associated with quinine, a type of flower that the bees would not visit.

It took five different learning sessions for the control group to figure out which of the colors gave them sugar and which gave them quinine. They could remember which of the flowers to go to after three days.

On the other hand, the group that was exposed to Roundup had a difficult time learning which of the flowers gave the reward and after two days, they forgot anything they had learned previously.

Photo: YouTube/Turun yliopisto – University of Turku

In a press release, Marjo Helander, an Associate Professor from the University of Turku, said: “We focused on the cognitive traits of the bees because these traits determine the successful foraging and social behavior of social insects and therefore their fitness. I am really worried. Even one very small acute dose had a harmful effect on the bumblebees.”

Another test was done involving an odor challenge and two basic color tasks. Both groups of bees were able to do those two tasks successfully. It seems as if bees that were exposed to Roundup could still sense color but they had become somewhat colorblind. Their sense of smell seems to be unaffected, as well as their long-term memory.

Docent Olli Loukola, who is from the University of Loukola, agreed with Professor Helander, saying that the results were ‘=”quite worrying.” He went on to say: “Even small disturbances in color vision can be catastrophic in terms of foraging and nesting success.”

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