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Even honey bees struggle with air pollution

Did you ever look at the blades of a fan and notice how the leading edges gather crud from the air? It’s gross, and whenever I see it, I imagine breathing all that stuff.

It turns out that honey bees also have a problem with dirty air. A new paper appeared earlier this month in the Proceedings of the National Academy of Science that shows insects, specifically the giant Asian honey bee, Apis dorsata, and the common fruit fly, Drosophila melanogaster, can suffer severe health problems due to air pollution.

Stress, heavy metals, and poor health

The paper, titled “A field-based quantitative analysis of sublethal effects of air pollution on pollinators” compared individuals from extremely polluted areas of India with individuals from less polluted areas over a three-year period. The differences were stark.

The lead author, Geetha Thimmegowda, and her associates examined the bodies of over 1800 bees. Of one bee in particular she said, “Its body looked like a war zone.”  In addition, many bees had wing edges “crusted with dirt” and others were “covered with all sorts of crud and particles.”

When the wing deposits were examined, the researchers found toxic heavy metals, including arsenic, lead, and tungsten, and eighty percent of the heavily-coated bees died within one day of capture. Postmortem examinations revealed that the bees in the most polluted areas showed signs of poor cardiac health, stress, and compromised immune systems along with damaged antennae.

Bees from the less polluted areas were able to visit up to twice as many flowers per day as their polluted kin and they lived longer. The fruit flies yielded similar results, including indications of stress and shorter lifespans.

Other research agrees

India has a major problem with air pollution and is home to 9 of the top 10 most polluted cities in the world. But previous research in other countries has shown that car exhaust interferes with honey bee navigation by masking scent cues, which makes finding flowers difficult. The current research adds another layer of complexity, showing that pollution can damage a bee’s overall health as well as its ability to navigate.

The authors stress that these are sublethal effects. In other words, they do not kill the bee outright but shorten its life and interfere with its ability to function normally.

Death by a thousand cuts

Those of us who live in less polluted environments should not be complacent. Many things about our modern world impair our pollinators, and it’s impossible to know how much each factor contributes. Even if things like air pollution contribute only small amounts to colony demise, when you start adding them together, you can see that “just a little bit” of something might be enough to tip a colony over the edge.

Take an average colony of bees. A certain percent might die of exposure, predation, or bad genetics. More might die of pesticides, parasites, and pathogens. You can also add habitat loss and fragmentation, loss of forage due to invasive weeds, or the chance of getting diced by a lawnmower. And now air pollution. How many will that kill? We don’t know, but we can see the news is not good.

At some point, not enough bees remain to sustain the colony. Lots of people say, “My colony just died. It seemed fine, I treated for mites, I supplemented its food, I checked for disease, but it still died. What did I do wrong?”

When I hear that, I always wonder. Maybe the beekeeper did nothing wrong. Maybe a three percent loss here, and a five percent loss there, and a seven percent loss later on combined with all the other misadventures was enough to make it fail. I don’t believe there is always one big overriding cause of colony death. Many times it could simply be death by a thousand cuts.

The biggest job of all

We still need to do everything we can to help our bees. We need to monitor, treat when necessary, and give our colonies a leg up if they need it.

Sometimes, though, things spiral out of our control. We must remember that the world our bees are forced to live in is not the one they evolved in. The best thing we can do for all living things is to take giant steps toward saving our environment, our planet. This is job one for all of us.

Rusty
Honey Bee Suite

Air pollution affects all species, not just humans. Sometimes we forget.
Air pollution affects all species, not just humans. Sometimes we forget. Image by sm-ekb2005 from Pixabay

Comments

Gary Kaufman
Reply

As always, thank you. I suspect there would be some kind of correlation as well when it comes to the impacts US wildfires have on populations. Just thinking back to how horrible 2015 was here in the PNW and now of course major parts of Colorado and California [again]. Granted it would be anecdotal, but wondering nonetheless if the bigger beekeepers have considered that as part of the “failure to thrive” issues.

Rusty
Reply

Hi Gary,

I agree with you. It must be a factor in those areas that have lots of fires. Wildfire particles seem big to me, so imagine how big they must be to the insects that need to fly through them.

Andrew
Reply

Hello Rusty

I’m concerned what effect 5g could have on their 1mm square brains, especially with navigation.

Also on another subject, comb honey. If you put all the vegetables you know in a pot & made soup, we wouldn’t be able to taste any individual vegetable. As is with extracted honey. I’ve found that’s a good way to get people to understand the different taste experience they will have trying comb honey. Sorry if you have said that before Rusty.

Best wishes
Andrew

George Norman
Reply

Hi Rusty:

Insightful as always.

Our bees may be more susceptible to this type of pollution than other insects, because the workers would fly a lot farther than other insects in order to forage far afield.

It also struck me that our domestic bees have a huge advantage over more solitary insects, in that when a colony is assaulted by pollution, or non-lethal stressors, the queen can usually kick it into gear and lay more eggs to keep numbers up. This, of course, takes a toll on our queens, with the consequence they would run out of sperm or ova sooner.

In an age of decreasing queen quality, it would be interesting to quantify the effect pollution has on queen longevity and performance.

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