Clearing the Air: The Impact of Air Pollution on Bees (Ep. 17)

Air pollution is a significant problem today, and its impact on human health and the environment is well-documented. In this episode, we talk about recent research that has shown air pollution can also harm the health of bees. Our guest, Dr. Hannah Sampson, is studying how air pollution affects the bee’s gut bacteria and microbiome composition and the subsequent impact on their health.

The balance of bacteria in the bee gut microbiome is vital to maintaining bee health. Any disruption to this microbiome could pose a risk to bee health, pollination, and global food security. Hannah’s research found that air pollution, specifically black carbon pollution, can significantly impact the bee gut microbiome.

In her study, Hannah sampled bees before and after exposure to black carbon pollution. She then measured the abundance of bacteria in their gut to observe any differences. There was a significant change in the quantity of two beneficial bacteria that are vital to the health of the bee gut microbiome. This disruption could have a lasting impact on the bee’s health and their ability to pollinate crops.

Dr. Hannah Sampson is a postdoctoral research associate in the Department of Genetics and Genome Biology at the University of Leicester. You can read more about her study here, follow her on X (Twitter), or connect on LinkedIn.

Good to know

Black carbon may be an unfamiliar phrase for something we are all familiar with. As Hannah shared, black carbon is produced both naturally and by human activities and is what we commonly call soot. It mainly comes from diesel engine emissions, cook stoves, wood burning, and forest fires. It actually doesn’t stay in the air for a long time, but its effects are highly damaging in that period. According to Inside Climate News, one gram of black carbon contributes 100 to 2,000 times more to global warming than one gram of CO2 on a 100-year timescale.

Transcript

[00:00:00] Smoggy air doesn’t just look and smell bad, it’s dangerous for our health. The World Health Organization reports that outdoor air pollution is estimated to have caused 4. 2 million premature deaths worldwide in 2019. But breathing all that polluted air doesn’t just harm us humans. It has devastating consequences on everything that breathes, including bees.

Today I’m excited to have Dr. Hannah Sampson with us. She is not an entomologist or bee researcher, but has done some very important work involving bees, air pollution, and the damaging effects bad air is having on bee health. Thank you for joining us, Hannah. You work in the Department of Genetics and Genome at the University of Leicester, and this research was undertaken by the air pollution bacteria [00:01:00] team.

What made you decide to look at bumblebees as part of this research? So yeah, that’s right. I work in the air pollution bacteria team and this research was part of my PhD project where I investigated the effects of air pollution on bees and their gut microbiome. Our team’s research was initially focused on how human associated bacteria adapt to air pollution stress and how this impacts host pathogen interaction.

And the previous work on bacteria associated with human lung disease found that air pollution has a direct effect on the colonization of these pathogens. And this work was the first study to identify that air pollution directly affects bacteria. and has motivated further research into these effects.

The decision to look at bumblebees came from my PhD supervisors who saw the importance of the bee gut microbiome and how it was a vital component to pollinator [00:02:00] health and wanted to investigate the effect of air pollution exposure on bee gut microbiome. So I’m sure I don’t have to explain to this audience. But bees are really critical to the maintenance of natural ecosystems and of course are essential pollinators in agriculture, making the study of bee health a really important area of research.

And for this research we are using the buff-tailed bumblebee, Bombus terrestris, as they are native pollinators in Europe as well as globally, agricultural pollinators. So you looked at black carbon air pollution. Can you tell us what that is, where it comes from, and the dangers it poses to bee and human health? So, yes, black carbon is an air pollutant and air pollution is made up of a mixture of gases and solid particles that are present in the air.

And contaminate our atmosphere. So you have gases you’ve probably heard of, things like ozone, [00:03:00] carbon monoxide, nitrogen dioxide. And black carbon is essentially soot. It’s a by product of fossil fuel and biomass burning. And it’s a major component of the particulate matter air pollution. And the particulate air pollution is everything that’s not a gas.

So it’s made up of tiny microscopic pieces of solids or liquids that are suspended in the air. And air pollution comes from natural sources, so things like wildfires or volcanic eruptions. But also man made sources like burning of fossil fuels, vehicle emissions, and industry. In terms of bees, there is less known about how pollution affects bee health, but we’re beginning to understand how these pollutants interact with bees.

So we know that when bees are flying and foraging around, of course, they’re in the air, coming into contact with these pollutants, and the particulate pollutants do accumulate on bees’ bodies, [00:04:00] specifically on their heads, legs, and wings. Um, you can imagine their hairy bodies are like magnets for these particulates. We also know that these pollutants are likely ingested because there have been screenings of honey has found the presence of these different pollutants in honey as well.

And there’s also been research looking into bees that are foraging in highly polluted areas. And they’ve shown that these bees have changes to their behavior. They visit flowers much less frequently and also have changes to their physiology, their heart rate. But the work that we have done recently, which has been submitted and is out as a paper, is the first study looking at the impact of black carbon on bees.

And we saw significant changes to beneficial gut bacteria. And also alterations to gut microbiome, which is important for bee health. So these [00:05:00] particulate pollutants are an underexplored risk for the health

of insect pollinators. So how does black carbon effect bees? We found that black carbon changes… The abundance of a couple of different types of bacteria that are beneficial to bee health. So, one of them, Gilliamella, is really important for carbohydrate metabolism, so breaking down lots of different food sources. And the other is also Bumbalactobacillus, which is important for, immune and hormone roles in the bee as well.

So changes in the abundance of these beneficial bacteria likely has knock on effects to bees ability to

use different food sources and also resist pathogen infections as well. Can you explain a bit more about gut microbiomes? The gut microbiome is a group of microscopic organisms, or microbes, [00:06:00] that live in the gut. This includes bacteria, fungi, viruses, and bees, just like humans have their own gut microbiome. Humans have a huge diversity, so many different types of bacteria in their gut.

Whereas bees have a distinct gut microbiome, which is made up of just a few different types of core bacteria. And these bacteria have a close relationship with bees and are specialised, having co evolved with bees over millions of years. And core bacteria in the bee gut microbiome are beneficial to bee health and found in many different species of bee.

This includes honeybees and bumblebees across different environments all over the world. And the maintenance and balance of this core gut microbiome is a key element to bee health, which aids in the digestion of food, providing essential nutrients for the bees, promoting post weight gain and[00:07:00]

protecting them against pathogens and environmental stressors. When bees hatch, they’re essentially microbe free and their gut microbiome forms over the course of a few days from interactions with bees in the colony and the colony environment. And once these bacteria have colonized and established, the adult gut microbiome composition, or the arrangement of different bacteria in the gut, remains pretty stable for the remainder of the worker’s lives.

But the bee gut microbiome can be disrupted, such as with use of antibiotics. And this increases, uh, infection rates and mortality. And how did you conduct this study? We focused our investigations on the core bee gut microbiome, as the balance of different beneficial bacteria in the gut is strongly linked to health.

And for this work we used age controlled adult bees that already had their fully formed gut microbiome. And we measured the gut microbiome, then exposed bees to black carbon for a number of [00:08:00] days, and then measured again. And we found that black carbon air pollution exposure changed the amount of core bacteria in the bee gut, disrupting the balance of these beneficial gut bacteria.

And these changes we didn’t see in the control. And this is concerning as black carbon disrupted the established gut microbiome for adult bees. This may affect the functionality of the gut microbiome, such as the ability to use different food sources, and resist pathogen infection.

. So you look specifically at black carbon, do you believe that other air pollutants can be just as damaging to bee health? It’s difficult to say for sure because it’s such a new research area, and there are lots of different kinds of pollutants.. These pollutants can have different effects, they’re not all going to have the same impacts.

But, other studies have shown that the different pollutants change, um, bees’ [00:09:00] behaviour and survival rates, and but we’re not sure the degree to which each pollutant is having an effect here. And this needs to be given more attention because we can’t assume that they’re all, they’re all doing the same thing.

And in nature, there’s always multiple different pollutants. You’re not going to have just one side of things happening. So having, looking

at these knock-on effects is also important. And other studies that have also looked at how air pollution affects the bee gut community. Um, finds that there are increases in, uh, some bacteria and decreases in the abundance of other bacteria. So they found some similar findings to what we saw, but, uh, not exactly the same. So… Initially, from the research we’ve already seen, it looks like different pollutants are affecting the bee gut microbiome in different ways, and it’s important to fully establish the impact of different pollutants, both on insect [00:10:00] pollinator health, because specific pollutants have these distinct effects on the abundance of the core bee gut microbes.

So where would you like to see the research go in terms of air pollution and pollinator health? So this is a really important and critical research area, especially right now as air pollution levels are increasing, and we’re more and more reliant on our bee pollinators for our growing human population.

I’m hoping to see more research into how environmental stresses like air pollution affect bees and to what extent so we can better understand how pollution affects these important pollinators. I would like to see more research into the effects of these different air pollutants on bees and pollinator health because understanding bee health and the factors that affect it are increasingly important both for our global biodiversity and [00:11:00] food security.

From digestion to the ability to fight off pathogens, the balance of a bee’s gut microbiome is essential for their survival. It’s impossible for bees to avoid air pollution. Learning more about how the different types of pollution can impact a bee’s health is critically important as we work to support their survival.

Thanks so much to Dr. Hannah Sampson for introducing us to another aspect of bee health. You can get more information about Hannah’s study at thebeesknees.website, where you can also join The Hive to receive our twice a month newsletter. On behalf of the bees, I thank you for listening. Until the next episode, keep buzzing.