Flowers Contaminated With Metal Behind Bumblebee Decline

More than a little evidence has linked pesticides to the alarming decrease in the number of bumblebees in the U.S. Now new research from the University of Pittsburgh suggests another factor: metal pollution.

According to a recent study in the journal Environmental Pollution, bumblebees are ingesting metals such as aluminum and nickel in toxic amounts. The metal comes from flowers that have been grown in soil contaminated by exhaust from a combination of motor vehicles, industrial machinery and farm equipment. Modern agriculture practices, in which more and more tasks are mechanized, are contributing to the decline in bumblebee numbers.

Bumblebees can detect the presence of certain metals in flowers by tasting them, but not from afar — that is, by  the time they’ve identified metal, they’ve ingested some. The bees are able to ignore some metals and will still forage from contaminated flowers, so moderate to high levels of metals can accumulate in the tiny creatures’ bodies over time.

Tia-Lynn Ashman, a biological sciences professor at Pitt and a PhD student in her lab, George Meindl, studied bumblebee behavior around uncontaminated and contaminated Impatiens capensis. This North American flower provides an “ideal place” for bumblebees to seek out food as it has large blossoms and produces plenty of super-rich nectar daily. The researchers collected fresh flowers for two weeks and observed the bees’ behavior in a lab.

Notably, the bees tasted and then left flowers containing nickel. But this was not the case for flowers contaminated with aluminum. The bees foraged on these for as long as they did uncontaminated flowers, adding to the levels of that metal in their bodies.

Why the bees sensed nickel but not aluminum is not yet known. Meindl cites previous studies that found higher concentrations of aluminum in flowers than of nickel, a suggestion that the bees may actually be “more tolerant or immune” to the presence of aluminum.

40 to 50 percent of the U.S.’s population of honeybees has been wiped out this year. The ramifications for supplies and prices of U.S.-produced honey and of almonds, fruits and vegetables pollinated by honeybees are huge and beekeepers have become more and more aware of the damage pesticides — especially neonicotinoids — can cause. In the case of bumblebees, these powerful chemicals are just one threat. As the Pitt researchers’ findings suggest, looking even more closely, and critically, at multiple aspects of modern farming practices and their environmental impacts (pdf) is necessary to ensure their survival


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Photo from Thinkstock


.1 years ago

I really love your write-ups guys continue the good work.
metal roof colors

Carrie-Anne Brown

sad news but thanks for sharing

Debbie Crowe
Debbie C4 years ago

I do NOT have a shortage of Bumblebees in my yard. I haven't seen any so far this year, but last year they got mad at me because I was trying to water my flowers. I left that area and came back later!

Mark Donners
Mark Donner4 years ago

America is the source of terrorist organizations, corporations like the oil companies, Monsanto, Syngenta, Dow, Bayer get away with global terrorism. They are criminal operations that must be stopped.

Waheeda S.
Waheeda E4 years ago

This is so sad! Now what can we do to change this for the bumblebees??

Gary L.
Gary Leeson4 years ago

It is not about blaming one contaminant over another - it is the combination of environmental pollutants including pesticides and habitat decline from population growth and climate change that must be considered. As agronomists if we can mitigate the effects by minimising the exposure of bees to neonicotinoids then we have done our part. We can't stop people driving cars but we can choose our pesticides more wisely.

Melissa Adelson
Melissa Adelson4 years ago

This is very alarming. I wonder if they can adapt to such a dire situation as this.

Marilyn J.
Marilyn Jewett4 years ago

Since honey is basically bee puke, if they are ingesting these metals that are making them sick and die off, aren't we also ingesting the same metals that's killing them off? That sounds very concerning doesn't it? We could already be suffering from this ingestion for the past several years and not realize it because it's a small amount or we can't explain some sickness as we don't have evidence or proof that this ingestion is negatively affecting us. Something to "bee" aware of.

ali a.
ali a4 years ago

Poor lttle things.

Katheleen Sauret
kathleen Sauret4 years ago

That is sad! Yes, save the bees!!!! I got stung by a bumble bee last year (for the first time in my life)......and I haven't gotten sick since. A friend told me that being stung by mulitple bees can't boost your immunity....and this big guy certainly did mine.