Plight of the bumblebee

Honeybees are used worldwide as pollinators, but as numbers dwindle their price is increasing. Could bumblebees hold the answer?
26 August 2014

Interview with 

David Pattemore, Plant & Food Research's Ruakura site


In the news we often hear about the demise of honey bees and bumble bees. Dr David Pattemore, a pollination scientist at Plant and Food Research's Raukura site spoke to Chris Smith and Simon Morton about how he's trying to help the future of pollination... Bumblebee - Bombus terrestris

David -   So, what we're trying to do is actually develop alternative pollination systems for growers in New Zealand.  And that's largely because of the threats that are facing honeybees.  The biggest problem for growers is it means that honeybees get more expensive.  So, they have to pay hundreds of dollars per each hive to put it in their crop.  They want 8 hives per hectare, that's a lot of money.  So, what we're trying to do is we're trying to develop alternative systems.  One of the big things that we're doing is trying to turn bumblebees into a system that growers can manage in their orchards.  So currently, if you want bumblebees in an orchard, you have to pay over a hundred bucks for a cardboard box like this.  I'll just open this absolutely carefully.  In here, there's probably about 100 bumblebees in a small colony.  I'll turn the microphone on and you can hear it.  If I whack it, they'll start coming out.

Chris -   Don't do that.

David -   So, this is what growers have.  Often they have at the moment if they want bumblebees.  But this really a design for glasshouse tomato pollination.

Chris -   When you say a hundred - because if that were a box of that size of honeybees and you'd have a 100,000 in something that size.  Do bumblebees live in smaller groups than honeybees then?

David -   They definitely live in small groups.  That's one of the big limitations.  If you're just wanting numbers of bees, get yourself a honeybee hive with 60,000 bees.  This is only maybe 100 to 200.  This works well in glasshouses for tomato pollination, but when you put it out in the field, they often really struggle to figure out how to get outside the box to start with and that they're actually meant to forage.  It's just simply too expensive.  If you only got a couple hundred bees and a box like this, one will just buy a honeybee hive.

Chris -   So, we need to learn to think outside the box is what you're saying?

David -   There were go.  

Chris -   So, it's a problem of scale.  If you've only got 200 bees and you've got 200,000 plants, and you had 200,000 honeybees, they would have no problem - one bee per plant on average.  So, the bumblebees, why can't you just have more bumblebees then?

David -   Well actually, bumblebees have one thing in their advantage.  So, some of the studies, especially with kiwi fruit, I found that one of these bumblebee workers does the job of 50 honeybee workers.  So, that starts to even out a little bit more, but you still need a whole lot of these and these are simply too expensive.  So, what we're trying to do is develop ways that growers can harness the power of wild bumblebees because there's bumblebees out there in the environment anyway.  The key thing for the grower is that they like to count things.  If they can't actually count and say, "I have 10 colonies of bumblebees," they won't change their management at all.  They'll just bring in the same amount of honeybees.  So, we want to give them away to find out how many bumblebee colonies they have in their orchards and then give them tools to manage those colonies.  So, what we've developed up on your screen there is the picture of our bumblebee bunker.  And that's mark 2.0.  It looks kind of like a popcorn - not popcorn, the rice crispy slice.

Chris -   It looks like a Breeze Block.

David -   Yeah, Breeze Block, something like that.

Simon -   Have you got a designer onboard or is that...?

David -   I think we haven't got a designer onboard and that's part of the problem.  This is actually like a flat pack construction style because we've expanded to a massive trial.  We've got a thousand of these nest boxes going all throughout the country.  We've got 5 regions in New Zealand ranging from coastal avocado orchards to high country red clover stations in Marlborough.  And we're putting these in the ground and the idea is that we want to build the best nest box that attracts queen bumblebees.  So bumblebees, rather than honeybees, they continue year-round.  Bumblebees have an annual cycle and only the queen survives over winter.  So, those queens hibernate in the ground and they come out in spring and they're looking for a new nest site.  So, we want to build something that to them is just perfect.  This is where they want to set up a new colony.  So, we've been trialling it for two years now.  We've had great success which enables us to expand to this new trial.

Chris -   So, this is like the bee ideal home exhibition, isn't it?

David -   Absolutely, yeah.

Chris -   So, how do you decide that whether the bees like the home you've made for them or not?  What do you measure?

David -   We measure whether they turn up for a start.  So, it's interesting.  The simplest measure that most people around the world use is occupancy.  Did you ever see a bumblebee or a sign of a bumblebee or think that there may have been a bumblebee inside this box?  Globally around the world, when they do these trials, you get about 3% success rate.  You're going to have to put out 300 of these to get just a few colonies in your orchard which really doesn't work.  New Zealand has this reputation for doing really well with these artificial nests.  And so far, overall with our trial, we get about 30% occupancy.  Some orhcards, it's up to 60% occupancy.  That's pretty damn good.

Chris -   Could you boost that by putting some kind of smell or chemical in there that might lure the queen in?

David -   Yeah, we've tried that.  A lot of the lures have been sort of based on floral scents.  They're not looking for flowers when they're looking for nest sites.  So, that doesn't really work, but we're trying to sort of distil an essence of disturbed Earth.

Simon -   It might be like cavalier bremworth I'm thinking.

David -   ... a little kitchen sink, yeah.  Well, we actually have used carpet underlay and that's works pretty well, but that's a fibre.  So, the thing is, bees actually find it really easy to find their nest sites.  And that the key thing for us is understanding what is that trigger that when a bee comes into our nest site, what makes it think, "Ah!  This is the place I want to stay" rather than just going back out again.  So, one of the other things that we've been doing especially because there's one bumblebee species, we've had a lot of difficulty getting is that we're putting little radio transmitters and there's another picture here.  On the back of this bumblebee queens - so, we're actually able to track them as they're searching for their nest sites.  And we actually get at very early stage, we get a picture of where these bees are choosing to nest.  We've got a masters student from Massey University who's doing the study.  She was up in the Netherlands and she's just come back to New Zealand.  she's doing it again in New Zealand.  actually, chasing these bees across the landscape.

Chris -   Does she use G - B - S?

David -   No.

Simon -   Is that ethically - I mean, that's not fair.  I mean, that's like me having a rats tail 9 metres long.

Chris -   What we're seeing here is a bumblebee with a tail.  I presume that's the antenna, that thing stringing off the back.

David -   And you can see the little package.

Chris -   And it's about three times longer than the bee is.  Does that impair the bee when it flies around?

David -   Occasionally, it gets caught in the flowers, but it doesn't seem to bother them too much.  More of the problem is it gets caught and then it gets ripped off, and then we lose the bee.

Simon -   What about the weight of the little transmitter thing though?

David -   So, the weight is about a quarter of the body weight.

Simon -   Wow!

David -   That, you've got to take in account...

Chris -   It's the size of a grain of rice, the little thing you've got stuck on there.

David -   These bees will easily carry their own body weight in pollen and nectar.  So, I brought along a backpack that's a quarter of my body weight.  But that's very difficult to carry, but for the bees, they're used to carrying these sort of weights.  The interesting, when we first put a transmitter on the bee, I was quite nervous about this method.  It was blowing 30 knots at our research centre.  I thought, "Well, I can't release the bee into the wild."  I took it up to our orchard.  We have sort of good protection from the wind. I got there and I released this queen as she goes straight up over the top of the projection, into the wind and disappears.  Never saw her again.  So, they certainly have no problem flying with this.  We do need to make sure they're in good condition, that you get it good feed and active before you release them, but they fly with no problem.

Chris -  And is it working?  Do you think this is going to be a viable strategy?

David -  It certainly is.  It gives us a level of information that we're not able to achieve in any other way.  So, you can find colonies at the late end of the season when there's lots of work that's coming in and out, but it's almost impossible to find these early stage nests.  So, by putting these - when they first go to a nest, we can actually build up a picture of what is that nest site when those queens first say, "This is where I want to set up a colony."  We can figure it out and we can take those elements, build them into our bumblebee bunker design and hopefully improve the success rate.


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