Bombus Confusus Flies Again (Ep. 15)

The Bombus Confusus, or the confusing bumblebee, is one of the rarest bumblebees in Europe. This species was once widespread throughout most of Europe. It’s unique among European bumblebees, the only species with territorial males with enlarged eyes.

In the Czech Republic, this bumblebee is red-listed and protected by law. The workers usually appear on honeybee patches at the beginning of July; however, it was unclear where they came from and where they went after the patches dried up. This year, due to the cold and rainy spring, the mowing of potential host plants was postponed, and the bumblebees were observed flying on some clover patches between the apartment buildings in the town of Ceske Budějovice. Today, we’re talking to one of the researchers who found the Bombus Confusus and what he and his team did to learn more about this species. 

Michal Perlík is a researcher in the Institute of Entomology at the Biology Centre, part of the Czech Academy of Science, and also works in the Faculty of Science at South Bohemia University. 

Good to know

The International Union for Conservation of Nature (IUCN) has an older (2014) publication listing bees red-listed in Europe. It’s a scientific publication and not that reader-friendly. “Red List” is an IUCN term for creating an easily and widely understood system to classify species at high risk of global extinction. The IUCN lists 16 species of bees as vulnerable, 18 as endangered, and nine as critically endangered globally.

Transcript

[00:00:00] Bombus confusus is a species of bumblebee found in Western and Central Europe. In the Czech Republic, it’s a critically endangered species, but it was recently spotted earlier than normal in the southeastern part of the country. Researchers sprang into action, getting the city on board and putting in place a study plan.

Today, I’m pleased to have with us one of those researchers, Michal Perlik from the Czech Academy of Sciences and the Faculty of Science at South Bohemia University. First, I asked him to introduce us to the Bombus Confusus. The Bombus Confusus or the confusing bumblebee is by the IUCN organization considered one of the rarest bumblebees in Europe.

It used to be widespread through most of the Europe, basically starting the Western part of its distribution, starting in Pyrenees in the border of Spain and [00:01:00] France, and it continued all the way through the European part of Russia, across the Asian parts of Russia, uh, throughout the central Europe and reaching a lot of parts in the Southern Europe as well.

Except the peninsula, where it didn’t reach all the way basically to the Mediterranean basin. But in the later parts, uh, in the later decades, it has been somewhat decreasing, especially in the south. Likely due to climate change. But in Central Europe, it still somewhat prevails. But it’s very far from being as widespread as it used to be,

some, you know, 50, 60 years ago. It’s a kind of unusual species for the European bumblebees. In Europe, there is about 80 species of bumblebees, including those that just… reach, you know, a tiny little corner of Europe with their distribution and the only one of them that has territorial males with these like enlarged eyes, you know, like what a honeybee drone looks like.

So these males of these bumblebees look very similar and they are the only one who do these. The males [00:02:00] basically patrol some area where they wait for the young queens, for the young females. And they actually need like, uh, perching points where they would fill the weight. So they are also dependent on the structure of the habitat where they live, where they kind of need to have the good ability to look around with those big eyes to catch up to the females.

And also compared to many other of the more common species, they have very small nests and build them very slowly. So yeah, that’s the confusing bumblebee. And why is it nicknamed the confusing bumblebee? Very likely due to its color pattern, which is, uh, black with orange tail, orange end of the abdomen.

And it shares this kind of coloration with five or more other species that are very common in Europe. So it is very easy to mistake at the first sight. One of the most common bumblebees, the red tailed bumblebee, the Bombus lapidarius, the most common dark bumblebees, looks literally the same in coloration.

The only way they differ is… in the males, of course, because the Confusus has the [00:03:00] large eyes and the females have a very velvety, very short trimmed coat of hair. So if you look like a normal bumblebees , they are usually like very shaggy with different lengths of hairs and so on. The Confusus looks like it has been in a barber shop.

It is like very short, very trimmed all the way, all the hairs are the same length and so on. Also, there are some characters on the lower side of the body, but this very nice and clean look is very specific to him. So as you mentioned, this bumblebee is endangered here, but you found it in the Cesky Budějovice region.

How did that happen? This bumblebee actually has several localities across Czech Republic. We have known about this bumblebee appearing in Budějovice pretty regularly actually. But only in the later parts of the season on some honeybee patches that are already pre- planted for the bees. So we would know that the workers would appear in the beginning of July in these patches.

But we would have no idea where they came from and where they disappear after the bee patches [00:04:00] disappear as well. But every year for several years now, we have been able to observe them. And this year was the first one where probably due to… very cold and rainy spring a lot of this city mowing was postponed so a lot of patches of potential host plants were left intact to much later than they would usually be if it wasn’t raining the whole spring.

So we have noticed these, uh, bumblebees actually flying on some clover patches, basically in between the apartment buildings, close to the periphery of the town. So, uh, we contacted the city magistrate to basically ask them if they could postpone the mowing of these patches because of this rare bumblebee, because it’s not only rare,

in the whole Europe, it’s also red listed in Czech Republic, but it’s also protected by law in Czech Republic, which makes it much easier to get things moving. And the city magistrate basically was very helpful and took a very quick action to change the mowing [00:05:00] schedules for these parts until the clovers in these parts managed to be useful, yeah.

So was there anything other than the clover that was flowering in this area that you wanted to make sure the bumblebees had access to? Yes, at that time it was mostly the clover and the wisteria plants. Yeah, it’s one of the legumes. Yes So these were also the plants and they are kind of a compartment of its diets when it starts at the clovers when the clovers’ bloom is off the wisteria are starting and then there is the second generation or the second blooming time of the clovers if the mowing schedule or grazing schedule if you are lucky is ideal. So they basically prefer legumes all year round. So to them it’s very important to either have such a landscape such an area around where there are some legumes blooming the entire season or you may help this by somehow changing your either mowing schedule or grazing schedule.

Now it has been, so we are recording this and it is [00:06:00] the end of July. I’m going to assume that the municipality has mowed these areas by now. Are you still kind of going back and seeing, are the bees still hanging around, do you know where they have gone, and do you think they may return to this area next spring?

Yes, that’s a very good question. That’s what we are actually planning to do because as I said, this was literally the first year where we have noticed them before the one one and only locality where we knew them to be before. So we use this as a jumping off point to basically monitor how they behave when we cut down, when a little part of these like clover patches gets mowed down if they move somewhere around how far they are able to reach away from them.

So with this knowledge, we plan to basically propose a moving plan for the next season, which would already include this knowledge, which will make it a little bit more patchy, a little bit more heterogenic to basically connect all the spots where the clovers [00:07:00] and the thatches grow during the season. So that there are some, at least all the time with reasonable connectivity.

So they don’t have to fly too much because they seem to be very picky even though when there is a reasonable amount of clovers in the grass in the common lawns in the city greenery. They still prefer the ones that are very densely covered by the clover. So they don’t like to like look for the individual flowers.

They need big patches to harvest. So we are trying to focus, especially on these places where there’s a lot of cover of these host plants. Also, we still didn’t actually figure out where they nest around the city. We have been trying to track them, but when they leave the clover patches, they just beeline straight outside of the city,

so they are really difficult to track. And, uh, it’s kind of difficult to trace the nests in other ways than marking the females, marking the workers, and then slowly recording them and zeroing in on the nest basically over the whole season. But since they have very small nests, usually up to 50 [00:08:00] workers maximum during the whole season, it’s not that many insects that you can really track.

You had some success working with the city who was quite supportive. If other cities wanted to do something similar to support bees, what do you recommend? I think it always helps to have a diversified mowing schedule, meaning not to just cut everything at the same time and then 10 days later do it again and again, especially during the hotter months.

It’s really horrible. We are kind of suffering from it, especially in these seasons when you can tell a city has a bad mowing plan when you just go through the city and everything is just yellow, dead and pointy. And you can tell that the microclimate is suffering. In my opinion, the aesthetics as well and everything, it just mowed to dust.

But a lot of cities now are actually fairly flexible with this. I would say especially in the last year and especially in the Budějovice, in the České Budějovice, the city’s approach to these mowings has been fairly good, especially on these, especially when [00:09:00] they are notified of something that needs to be done or something that needs to be avoided.

They are very quick and the system seem to be working very well with the community of the local ecologists, hobbyists, or these non-state organizations that take care of these flowering patches or extensive lawns as they call them. Do you have a favorite bee? Well, yeah, of course I have many favorite bees.

Can you narrow it down to one, maybe two? Yeah. I’m a big fan of these, uh, pantaloon bees. They’re called the Dasypoda , the Pantaloon bee. They’re called that because they’re kind of very primitive bees, so they’re collecting apparatus are not these nice baskets on the hind legs, but basically the whole leg almost from the tip to the joint to the hip is covered with these very long hair brushes. So they really look like they are wearing these like very baggy pants. And they are not very good collectors also because they put a lot of pollen in this but because they are just a big collection of hairs they are losing it on the way when they when they fly so you can sometimes see them dropping stuff on the [00:10:00] go and they nest in the ground in disturbed soil. So when they dig the nest they look like they are doing these, uh, swimming breaststrokes, but with their hind legs, they are just like moving up and down, like swimming in the sand, basically.

On most of the nests, when they are reasonably large, they are hole in the ground that has this little pile of soil on top of it with the hole in the middle, and it has a little slide. On one side, but they basically just remove the soil to one side to slide away from this so that it doesn’t cave in. So they are very fun to observe and you find the nest typically in like in the southern parts of Europe, but in Czech Republic, they also, they also appear fairly frequently.

So when you find the nest, it’s a very nice place to make a picnic next to, because they are very hard workers, very ineffective, but very hard working all the time. Yeah, it’s a very nice bee. Final question. What do you believe are the biggest threats to native bees and what can we do about it? Oh yeah, there’s a lot of things I would say.

In our country, a lot of it has to [00:11:00] do with our past, where there was this collectivization of the landscape basically, where small fields or small pieces of owned land were basically forcefully joined together to create larger fields that could be, you know, uh… processed together and by this you sometimes create these large swaths of land that are not very useful to not only pollinators but also to insect diversity or animal diversity in general because even for example the rapeseed which is a very common plant to grow in the fields in here when it flowers it is used by many many insects. Because, you know, it’s yellow, the flowers are fairly rich in nectar.

The pollen is fairly usable. There is a lot of ease of access to the nectar and to the pollen. So they are generally very useful, but they bloom, you know, every now and then. And between the blooming and the rest of the season, basically the whole field is dead because not only do the growers or the, the farmers have to take great care to make sure that there’s only the rapeseed [00:12:00] plants growing in the field.

So they do it either by some mechanical preparation of the soil beforehand, which basically removes everything from the topsoil layer. And then on top of that, there can be some chemical treatment on top of these. And when they bloom and the flowers are no longer resources for the bees, there’s no more pollen, no more, no more nectar.

It basically turns into what some people call the green desert. It’s a very big square in the landscape that’s just green, but it’s absolutely dead because there’s nothing to eat there, nothing to feed on, nowhere to live. So this is, I think, one of the life problem. Of course, climate change doesn’t really help with this either.

I would say maybe one more thing that people are now more and more willing to do, and cities as well, is to basically establish these, uh, flowering lawns or flower patches in the cities, which are used as a foraging grounds for these bees, for pollinators in general, that are managed in different regime than the normal lawns, because it’s often much easier to plan when you [00:13:00] say this patch of ground will be managed in this system or will be managed this way and the rest of the let’s say park or the greenery of the place will be managed this way so you can at least leave little patches little islands that are useful and if they are connective enough and if there is enough of them they can actually provide for the pollinators within the cities fairly reasonably, but what is important about them.

It’s really helpful to be from the locally sourced plants. So if you actually can get seeds to the local plants from the to the regional mix of seeds, that is helpful, or you can just basically open up the soil and wait for what grows in there. As long as you manage it properly, it will probably not over, no, at least in the first few years, you need to somehow manage it to make sure it doesn’t get overgrown with grasses and these pioneer plants.

And second thing about them, they have to be spatially kind of connective, but they also have to be temporarily connected. That means in time, there still has to be a network of these flowering things. So if you create your flower patches and all of the [00:14:00] flowers will finish blooming in the middle of June then you didn’t really help you have basically created what’s called an ecological trap. You will pull all the insects or all the little animals to the one place and when it’s finished blooming they have nowhere to go.

They are just stranded on this dead patch of greenery. So it is not as easy as some people think but I think as long as you create enough of these patches with a reasonable plant composition, then you can even within fairly large cities support some diversity of these insects. This episode was extra special for me as I live in the Czech Republic and The Bee’s Knees is produced in Prague.

It was such a joy to connect with a local researcher and hear firsthand how specific interventions can have such spectacular effects. My thanks again to Michal for his time, and you dear listener for being here. If you’re enjoying learning more about wild bees and their special lives, it would mean a lot if you could tell a friend about the podcast, leave a review, [00:15:00] or sign up for the newsletter.

Thank you. As always, be sure to visit thebeesknees. website for more information about today’s episode. Thanks again for listening, and keep buzzing.