Gut Check for Urban Bees: Hidden pollinator pressures in cities (Ep. 76)

What if a single wild bee could tell us the story of an entire city? As urban areas grow, they break up natural habitats, change which plants can thrive, and expose wildlife to new pollutants and disease risks. Yet the tools we usually rely on to track biodiversity rarely capture the hidden pressures animals face—especially wild bees, whose pollination work supports everything from community gardens to major crops.

A new study suggests these bees may be carrying far more information than we realized. Researchers found that the microbiomes of city‑dwelling wild bees hold detailed clues about both bee health and the condition of the environment around them. In other words, each bee acts like a tiny environmental sensor, offering hints about local plant diversity, pollution, pathogens, and even chemical stress in the landscape.

To explore this idea, Dr. Min Tang and her team studied the gut microbes of mason bees collected from ten urban farm sites across Suzhou, China. Their results were both eye‑opening and worrying: the bees’ pollen diets showed a heavy dependence on a small set of flowers; honeybee‑related viruses were turning up in wild bees; and antibiotic‑resistance genes—though still at low levels—were present. Together, these microbial clues paint a complex picture of how city environments shape bee health and the ecological networks they rely on.

Dr. Min Tang works in the Department of Biosciences and Bioinformatics at Xi’an Jiaotong-Liverpool University. Her Sustainable Be(e) Lab focuses on evolutionary adaptation, the gut microbiome, and host-symbiont interactions. This is the paper we discussed.

Good to know

Min’s team used metagenomic sequencing which is analyzing all DNA within an organism’s gut. For this study, they looked at the dietary pollen, gut bacteria and viruses, and antibiotic resistance genes in the mason bees found at their ten chosen study sites. 

Transcript

[00:00:00] Welcome to the Bees Knees. A podcast wild about native bees. Wild and native bees are under threat worldwide. In each episode, we look at actionable things we can do to support these adorable little guys whose pollination work is crucial for maintaining biodiversity. I’m Jacy Meyer, and I thank you for being here.

How much information can a tiny pollinator carry and what do you think that information can tell us about urban conservation? As cities expand and natural habitat shrink, the wildlife that lives alongside us has to adapt. Fast and sometimes the clues to how they’re coping are hidden in surprising places like the gut of a bee.

Joining us today is Min Tang to talk about what she and her team found studying the guts of Mason bees across 10 urban [00:01:00] agricultural sites in Suzhou China by looking at everything from dietary pollen to gut bacteria. And antibiotic resistant genes. They uncover a powerful new way to monitor ecological wellbeing in cities.

Enjoy this conversation accompanied by the delightful chirping of Min’s parrots in the background. So, your study shows that a bee’s gut can act almost like a microbial diary of its environment. What surprised you most about what these gut communities revealed about urban landscapes, and most importantly, the pressures that bees face there.

Actually shows many aspects that we would like to know. We got useful information as long as we check. The most surprising one is the diet composition, which includes the ornamental tree, Platanus , the plane tree. [00:02:00] It is not a normal choice for bees, actually, so it seems that the Osmia the mason bee.

Couldn’t have better choice. So that’s the one I think they face the biggest pressure from the city region. So you also found that urban bees often rely on a very narrow set of floral resources like you just mentioned. From your perspective, what does this tell us about how city vegetation planting, so perhaps like street trees or community gardens, could better support wild pollinators?

We know that Mason bee cannot fly far when foraging, so we placed them near the rape seed farm land with abundant flowers, which actually primarily supported the mason bees. But obviously if we look at the data, it’s. Not enough. They eat crops [00:03:00] like peas and tomatoes and even garden trees and grass, which are quite common in the city region.

So our cities can plant more trees with bee flowers across seasons. Buildings can have flower roofs rather than just green roofs. Every citizen can definitely help by simply diversifying their balcony with flowers like the strawberries and the tomatoes, which will taste better with bee pollination also, right? So we can help the bees and the bee can help us.

So the presence of honeybee associated viruses in the wild bees that you studied suggests some level of pathogen spillover. How concerned should we be about this overlap between managed and wild pollinators? And [00:04:00] what practical steps do you think could be done to reduce these risks? It’s inevitable that pathogens will be exchanged among organisms that overlap in life.

We found viruses not just associated with managed honey bees, but also other invertebrates and even vertebrates. These impacts on wild bees remain unclear actually. So it’s called calling for further. Study to avoid pathogen spillover from a managed honeybees. We again, need to provide more diverse food for wild bees, so they do not need to compete with honeybees as much crowding in the same flower region.

Another thing we can do is learn more about local bees and the better flowers resources for them. So let’s stick with our bees guts for a moment. [00:05:00] You detected antibiotic resistant genes in the bees, and even at like low levels. What might this tell us about human impacts on city environments and how could this information guide more sustainable urban agriculture or pollution management?

Right, wild bees collect water from the city environment and are directly exposed to whatever they land on, right, including soil, which means they can get access to the environment microbes. We humans always wash our hands to avoid the pathogens and at the same time the antibiotic resistant bacteria, but they do not.

The wild bee doesn’t wash their body hands. Another piece. Of background information about the bacteria here is that they’re very efficient at the DNA organization, they [00:06:00] have small genomes and they usually retain genes necessary for life, so they acquire antibiotic resistant genes when they are threatened by drugs.

Our data indicates different drug residues across sampling sites, which call for more efficient supervision or oversight of the drug use and wastewater treatment, as well as natural drug discovery and so on. Where would you like to see the research go in this area? The research go is to let us know more about the threats from the urban region because actually we don’t know.

We know there will be antibiotic resistant genes transfer among different bacterias, but we don’t know the [00:07:00] impact or the data support, what kind of antibiotic resistant genes transferred between different organisms. So these part will tell us which region or which site. has abnormal drug use. So maybe you can guide the government or institute to supervise the drug use locally and to maybe change or improve how they can treat those waste water.

Something like that. In your opinion, which aspect of urban living for bees is the toughest on them? What puts the most pressure on their little lives? Firstly, must be the habitat because we occupied too much space. This is why there are [00:08:00] less and less flower resource for them. I think that’s the reason why they have lower dietary flowers.

So this is why I suggested if we cannot reduce our occupation, maybe we can increase some flower roofs or flowers for them so we can share the space at the same time. Right? And I think the organisms have their own power for the adaptation, but if they can not have enough food, enough diverse nutrition to against those threats.

I think that’s over. So just like people, if we eat well and sleep well, our immune system would work more efficiently. It’s the same thing, and we just leave other things to the same bind [00:09:00] bacterias. And, uh, they be themselves. As long as we provide enough flowers, I think bees would be fine in the future.

And may, uh, you remind me of another thing besides antibiotic resistance. Genes, actually there are pesticides, herbicide resistant genes. Those things we can also look at, it’s just in our study, in this published paper. we can find some range. So we cannot study all of them, but those things we can all look at in. So all my point is it’s just a simple bee gut that it can tell us so many information.

And sensitively tell us what’s wrong, what’s not right about the environment they were living in and the environment. Exactly the environment We also lived in. In all your times [00:10:00] working with bees and in ecology, has there been a discovery or some other part of your work that has given you hope or made you feel like you were making a difference?

Right. Um, why? I didn’t see the antibiotic research gene is the most, uh, crisis for them. Actually. That’s the crisis for us. Right. But actually the, uh, microbiome is a incredible thing because it’s under the lure, under the lore of the evolution. So the answer to your question is the more information we learn about the bees and the life, the more we can do to help, for example, planting flowers.

It’s quite easy and uh, everyone can do it. Also know more about bees, especially the native bees, so we can help the diversity conservation globally, uh, more reasonably. And for the natural drug development I just mentioned, we [00:11:00] have been trying to identify natural antimicrobial peptides from the wild insect guts, learning from the evolution instead of produce new antibiotics.

Artificial ones, right? We shall slow down on solely human or economic development, but learn from the nature for integrated and healthy development. The One Health aim, that’s what I saw. Min’s research shows just how much these small pollinators can tell us about the environments we share. From the flowers available to them to the pathogens they encounter to the chemical pressures shaping their health.

One finding that particularly stood out to me was the presence of antibiotic resistant genes in the bees microbiomes. It’s a distressing signal that we need far more research into how [00:12:00] antibiotic use environmental contamination and microbial spillover are affecting wildlife. What that means for the broader ecosystem and public health.

Thanks to Min and her parrots for joining us today, and thank you for listening and hopefully sharing this episode with the Bee Loving Friend. Do visit the Bees Knees website to learn more about the work Min is doing. Until next time, keep learning from nature.