A Wild Bee Squeeze: A study in bee conservation (Ep. 74)

On the quiet Mediterranean island of Giannutri, a fascinating experiment has offered fresh insight into how managed honey bee colonies interact with wild bee communities. Led by Dr. Lorenzo Pasquali, the research team temporarily paused honey bee activity on the island—and the change was immediate. The familiar roar of half a million honey bees faded, and for the first time, the gentler buzz of wild bees could be clearly heard.

This rare opportunity helped researchers see just how much honey bee hives influence local food resources. Without honey bees competing for nectar and pollen, wild bees suddenly had far more to forage, leading to noticeable improvements in their activity and overall wellbeing.

At a time when climate change, habitat loss, and human pressures are putting pollinators at risk, understanding and managing this imbalance in beekeeping practices may be key to protecting biodiversity. Giannutri’s story invites us to rethink our relationship with bees to seek a balance where managed and wild species can thrive side by side, rather than compete.

Dr. Lorenzo Pasquali is a Post-Doctoral Reseracher at the University of Białystok in Poland. You can learn more about him here and this is the study we discussed.

Good to know

One of the main findings from Lorenzo’s research is that honey bees showed strong trophic resource overlap with wild bees. Trophic resource overlap for bees means how much honey bees and wild bees use the same food (nectar/pollen from the same flowers). This can often lead to intense competition that depletes resources for wild bees, especially when honey bee numbers are high or flowers are scarce. As we heard, it can affect wild bee foraging and potentially cause declines in their populations.

Transcript

74. A Wild Bee Squeeze

[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 am Jacy Meyer, and I thank you for being here.

Bees are essential partners in keeping our ecosystems and food systems running, but while managed honeybee colonies are thriving under human care, many wild bee populations are struggling. And that imbalance is raising important questions about biodiversity. On Giannutri Island in the Mediterranean

researchers found a rare chance to study this dynamic up close by temporarily closing managed honeybee colonies they could see how wild bees responded in real time. From changes in [00:01:00] nectar and pollen availability to shifts in foraging behavior, and even longer term population trends. In today’s conversation, Dr.

Lorenzo Pasquali joins us to share what he and his team discovered, why it matters for conservation, and how it could shape the way we think about balancing managed hives with wild pollinators. Set the scene for us please. Can you describe Giannutri Island?

So to imagine how the island is here to the position of this island in the  Mediterranean Sea, because it’s quite isolated from other islands and the mainland 10 kilometers apart for all other land.. And Giannutri Island is in the, in a half moon shape. So, and it’s, the surface is 2.6 square kilometers, so it’s [00:02:00] very, very small. And from one tip of the island, you can easily see the other tip of the island and.

You can just 30, 40 minutes walk, you can just visit all the, all the island. And it’s really impressive because there are no cities, no roads, so it just nature and some house because let’s say from autumn to spring, only 10 people live on the island so it’s quite no people isolated and the environment is amazing ’cause it’s all Mediterranean, um, shrubland or some woodlands.

And in some areas you can really just walking by, you can really smell the rosemary like a small heaven in the Mediterranean sea. And, uh. During the early spring when I was there to do this study, there were only [00:03:00] researchers.

Some people living there and bees and birds. That’s it. So it’s really isolated. You feel like any on an adventure. I’d say. That’s a beautiful adventure. A beautiful adventure is a absolutely perfect way to describe it. So what inspired you to study the relationship between managed honeybees on this island and the wild bees?

Yes, actually it’s a bit less poetic than the island description because the all the island is protected by the Tuscan Archipelago National Park, and in 2021, the National Park wanted to monitor the pollinator diversity on the island according to the European Pollinator Monitoring Scheme. And so they asked the University of Florence and Pisa.

I was working at University of Florence to start this project, and in the meeting to. Arrange [00:04:00] the staff to start the program. The idea of addressing the issue of the presence of honey bees came out by like a group brainstorming, let’s say, because there is a bit of growing body of literature addressing this topic.

So we said, okay, we’ll monitor the pollinator abundance and in addition, we would like to. Understand if there is competition between honeybees and wild bees on the island. So I say the idea came out from immediately from a conservation perspective because it’s a small island, so every potential stressors could be quite impactful.

So we need to experimentally study this topic. We also contacted beekeepers. The honeybees are on the island from 2018. And the beekeepers bring the hives in December and they remove them in, uh, [00:05:00] June. And they do this for economical, uh, of course, uh, reasons. And every year the beekeepers has to ask for permission to bring the hives to the national park.

So we made this, uh, agreement with the national park and the beekeepers in which we, we said, okay. The National Park will, uh, give you the permission to bring the hives for the next, uh, three years at least. It was 2021 and in exchange the beekeepers had to help us in the experimental study and. Teach us and allow us to close the beehives temporarily, and that that’s the, the core, the most important part of the study, the possibility to close the hives and study this.

So, so tell us what happened when you, uh, did temporarily kind of close up the honeybee hives. What did you notice right away? Yeah, the first non-scientific [00:06:00] thing that we saw, but it was really impressive. It’s the soundscape because you can imagine it’s a small island. We did these experiments in from February to the beginning of April, and in this period there were like, we estimated in abundance of honey bees, of three, no, let’s say half a million, more or less, half a million.

It’s a lot of honeybees and by working on the path on the island, you can really hear all the honeybees bzzz, buzzing, around and we pass from this situation to closure of the hives, total silence. So we, the soundscape is really the first thing that you notice. And after that, by paying a little more attention to the details, you can start hearing the buzzing of the wild bees so in our case, the true most [00:07:00] abundant of these were bombus terstris.

And you can also recognize them by the buzzing sound because it’s quite different. So I’d say that for me also, for my colleagues, the buzzing sound was first thing. Immediately notice as a difference. That’s the like personal experience from a scientific point of view. That’s what the national park wanted.

Also, we saw from the data like really evident statistical evidence difference between the data collected in the presence of honey bees and in the absence of honeybees. Maybe I need to specify that the honeybees were kept closed from one day. Uh, for one day if we cannot keep them closed for too longer, otherwise they, they’ll die of course.

So we need to alternate some demo, open hives, [00:08:00] close hives, and so on. And by collecting all the data, we saw that the, when honeybees were closed in the hives, there were a higher abundance of pollen on flowers. There a higher volume of nectar. And in response to the lower uh, exploitation done by honeybees bees, the wild bees changed the foraging behavior.

They actually, let’s say. Standing up all the foraging activity. I’d say that the wild bees improved the foraging time in absence of honey bees with this, I mean like they can make more foraging trips during the day. And because there are of course more resources on flowers so they can find them easily, so faster.

And at the same time, in the absence of honey bees, the wild bees were able to obtain more nectar from the [00:09:00] flowers because we were able to measure the time that each wild bees forage on single flower for nectar. And we know that this time. Correlated with the amount of nectar taken. Of course, it’s quite logical, but we also demonstrated that so, and the when honey bees were not there.

This time was longer, so it means that there were more nectar for the wild bees to collect.

So all this data were like from independent, also observations because they’re not a single experiment. There are many different observations, techniques, and methods, and all the methods point to the same direction of a really, really impact of honeybees. So. We notice from, say, from a human perspective, we notice a difference in the soundscape and also a visual from visual clues on the flowers.

But from a wild [00:10:00] bees perspective, the absence of honey bees created more food, more opportunity, and also more wellness, I’d say. Of course. So do you have thoughts on how we could better balance managed hives and wild pollinators? Understanding that it can have an impact on the environment, and after we have acknowledged it, we can start regulating the example, the honeybee hives density In some areas, of course, these can be done in protected areas at first, at least, because protected areas are areas that, uh, devoted to protect biodiversity.

So the human impact should be minimized. Regulating the honeybee density in that area is one of the steps needed to minimize these, um, their impacts. And of course, not all the protected areas are the same. For [00:11:00] example, in our case, Giannutri Island was a particular case because. It’s Island. So it’s a closed environment, isolated.

So every effect that honeybees can have is incremented because the wild bees were not able to find food so far from the hives because there are no food in the sea. Of course, maybe. So in, uh, the mainland, all the honeybees, the wild bees can go farther away from the hives to search for food. So. it’s really also context dependent.

And what we hope is that in many protected areas, the policymaker starts to increase the knowledge about the pollinator diversity, abundance, and by evaluating also the specific context, regulate the honey bee density. But we do not want to pass the message that. We are against honey bees. They’re no good bees and bad bees, heavy bees.

They’re just wild bees, [00:12:00] managed bees. But we can really hope that we can make them live together in a sustainable way without creating enemies, but creating allies. Say that. So in all your time with working with bees, has there been a discovery that made you feel like a bee hero? Like you were really making a difference?

Well, bee hero it’s a strong, a strong statement, but I’d say at two, two moments when I felt like a bee hero, it was doing the, because we did this study for four years in total. Actually five years because we continued also the, this year, so let’s say four years. And during the first year, which also was the, my first PhD, I started at the first day.

I started questioning, okay, I have to be on this island for a month. That’s a long time isolated with only with colleagues. What am I doing here? So we [00:13:00] started doing the experiment or observing the behavior of the bees, taking measurements of the volume of the nectar and flowers and just randomly in a moment, uh, on a day.

And I felt, okay, but I’m doing this. Not just for the sake of doing this, I’m doing this for a purpose, for helping this wild bee population. So wow. It was quite impactful for me to realize when I was on the physics, I’m doing something to help the conservation of wild bes and that was really amazing. let’s say, and the second moment was one year ago, maybe something more.

When we showed the all the results we had to the national park in another meeting, the national park said, okay, we have these results, and they took the decision to not give their authorization to the beekeepers. to bring the [00:14:00] honeybees on the island. So from our study, the national park make a conservation, an evidence-based conservation action.

Actually, it was not allowing the beekeepers to bring the honeybees to the island. And also we, with the other colleagues, we started understanding. Wow. So we have done some really something practical. We are doing something to help this population we can not know yet. It has been a positive impact because we need some time.

There’s some time lag between the conservation actions and the, the positive results that we can see, but we are very curious about about that. So. We replicate also in this year 2025. We replicated the measurements, we did the observations we did in a condition of prolonged absence of honeybees because there were totally no honeybees on the island.

And we [00:15:00] replicated all the, the measurement and we are planning to do also in the, in the next year to see if this decision of the national park had a positive impact. So. I’d say, and we felt somehow like a bee hero, like to protect the wild bees. Congratulations. I absolutely think that qualifies you and your team as bee heroes.

This study gave rare, conclusive evidence of how managed honeybees compete with wild bees. Even brief removals boosted nectar pollen availability, improved wild bee foraging, and revealed the pressure honeybee colonies place on fragile ecosystems. Over just four years, wild bee populations declined by 80%.

With honeybee competition, the most likely driver. In a world where climate change and habitat loss already strain pollinators, high hive densities can amplify those impacts, especially in sensitive places like islands and national parks. [00:16:00] The takeaway is clear. While many threats to wild bees are beyond our control, competition with honeybees is one we can manage.

This research calls for careful limits on beekeeping and protected areas, and sets the stage for broader studies to safeguard biodiversity. Thanks to Lorenzo for sharing the beautiful buzz of Giannutri Island with us and to you for joining in the adventure. If you enjoyed this episode, it would mean a lot if you could share it with a friend.

Thank you, and until next time, stay balanced.