Hello, my name's Lindsay Turnbull and I'm an associate professor in the Department of Plant Sciences
at the University of Oxford, and we're right in the middle of this very serious corona virus crisis right
now. And my students are all stuck at home and we want to keep them in touch with biology
and keep in touch with us. And so we're going to make a new series of videos and they're going to be called back garden
biology.
Welcome to this next episode of Back Biology. It's the Easter weekend and it's almost eerily
quiet around here. Even the buildings to those down have stopped. This episode is going to be about
bumblebees. They're one of the real favourite insects that people enjoy watching.
And we know that they're always doing something good. They're visiting our flowers, pollinating them. So we have a
very positive image of them. And lots of people want to do more for bumblebees and try to plant
the flowers that they like to come and visit and provide the kind of homes that they like to come and live in
at the moment in my garden. Most of the buzzing that I can hear around me isn't coming from bumblebees.
The most noisy insects at the moment are the hairy fosset flower bees. They're not a true bumblebee.
What's called a solitary bee. And you can find both males and females of those buzzing
around at the moment. They have a slightly HIGH-PITCHED Buzz. And every now and then we get
the kind of bass note of a bumble bee going past. And we are seeing them, but they're very,
very difficult to film because what those bumblebees are queen bumblebees coming
out of hibernation and they're big and glossy and they're going around
and they're looking mostly for nest sites and they're very difficult to film because although they
look large and ungainly and not white, they ought to fly very well. In fact, they can fly very
well indeed. And they go whizzing around co-authoring the ground in an area like this.
And they're looking to see where can they build a nest and particularly what they're looking for, his
old mouse nests, which make very good places for those bumblebee queens
to found their colonies. So let's do a little guide to some of the common queen
bumblebees that I'm seeing in my garden right now. And you're probably seeing the same species
there, maybe one or two additional ones, depending on exactly where you live. But before we start that,
I'm going to challenge you, get a piece of paper, get a pencil and see if you can sketch
a bee and see if you can get the main parts right. And then pulls this video for a second.
While you do that, men, you can press play again and see whether you got it right.
Okay. So here are the main parts of a bee that you should have included on your diagram.
The key thing when you're drawing any insects is to realise that it has three main
body parts. So I'm drawing the head in no child's
eyes, tongue and some antennae. Remember, high maths
is the four X and then the bits at the end is the abdomen.
OK. So all insects have this basic structure. This basic three part structure had four
X abdomen ancestrally the ancestral insect probably had a lot
more segments and they would have been a lot more similar. So before Axe is actually made up of
three segments that have been sort of been cemented together over evolutionary
time. So they look like a single segment now. And if you drawn legs and wings and I
hope you have that we should all be coming off the thorax. None should be coming off the abdomen.
Now, a bee is obviously an insect, but it's also belongs to a bigger group called the Arthropods.
All the reports are characterised by these jointed legs, and all insects have six
legs, three pairs of legs, all coming off the four x one from
each of those ancestral segments. I'm going to just draw the legs in on one side, because the other thing
that's characteristic of most insects, although some have lost them, are wings.
So if they have two pairs of wings and they've been modified a lot in different
insect groups. But in the bees, they always have two proper wings. The first
part, normally the largest. The second, Paris smaller. And they are actually kind of zipped
together as a little series of hooks between the front and the hind wing that keeps
it almost functioning as a single wing. When bees land, they often fold these
right back, actually over the body. So that's often where you see them and they snap them out with them up
before they fly off. So that's a basic bee structure.
OK. So what about some different common species of bumblebee? Well, they're not
that easy to recognise. So I'm going to show you three that I think are quite easy to recognise,
at least when the queens are around. This is at this time of year, of course, I've got my trusty play
dough. And so the common khadir bee is a ginger
bee and all ginger bee. So that means it has
a gingery coloured thorax and a ginger coloured abdomen. And sometimes
the abdomen is darker. It's streaked with black or blackish, but it always has
a uniformly covered coloured abdomen. It never has a separate colour on the tip of the tail.
And that distinguishes it from the tree bumblebee because they also have a gingery
for thorax and. The abdomen is really black, though not
really any hints of ginger at all. And at the end, a very clear white tip.
This is a newcomer to the U.K. It's flown in from continental Europe in the last
10 to 20 years, and it's established itself very successfully. And it does not seem to have
any negative impacts on any of our other bees. So it's to be welcomed. And you sometimes
see nests in old nest boxes or high up. There was one in my next door neighbour's garden,
which they'd made it inside a sort of pergola. And we used to see them coming and going. So
that's the tree bumblebee. I mean, another one that's easy to recognise when it's the queens
anyway is the all black red tailed bumblebee. So she's got
a black four acts, a black abdomen with a very clear red tip. We've got a beautiful, huge
one flying around our garden at the moment, but I cannot get her on film because she's remarkably
agile. So there's three common, easy bumblebees. Now, you might be thinking, hang on
it, but why bumblebees? To me, surely bumblebees aren't supposed to be black and yellow striped? Well, those
three are all quite common and they don't have any black and yellow stripes. But of course, other bumblebees
do. So here are a couple of common yellow and black striped bumblebees.
And they've got very similar names, as you see. They're called the white tailed bumblebee. And the buff
tailed bumblebee. And again, these are what the queens look like. So the white
tailed bumblebee, the thorax has one yellow stripe at the top. So it's a
black thorax with a yellow stripe at the top. The abdomen has one yellow stripe
quite high up, and then they have a clear white tail. The buff tailed bumblebee
is almost exactly the same. Also has a black thorax with a yellow stripe at the front
and the abdomen also has one yellow stripe. But then the tail is above
colour. And it's only now when they're queens that you can actually tell these two apart.
Once they start producing workers, then they'll all have white tails and you'll have no hope of telling
them apart. You may notice in your garden another stripy
black and yellow bee who has an extra stripe. So at this time of year, another queen
who has a yellow stripe here as well. That's the garden bumblebee. So there are actually at least
three common black and yellow striped bumblebees in addition
to these others that we see here. So you may think bumblebees just about Pourbaix.
But, you know, that's nature for you. We always have a lot of diversity and different
species. And that was a great time to look out for them. Try and grab a picture as they fly
past of the queens as they are searching for nest sites and feeding
their first brood of workers who are usual footage
of us trying to take pictures of queen bumblebees. Looks like this. You can see the bees flying
around very actively. They don't settle. They're looking around the base of trees. They're looking
under bricks and vegetation. They're looking for nest sites, not for nectar.
But sometimes they do stop and fade. And here is that same queen falling
out of a fertility flower as she is heavy and the inside of the petals are slippery. And there she
goes again. Just needs a bit of practise. freeze-Frame we see two yellow stripes and a clean
white tail. So this is the queen of the white tailed bumblebee. For contrast,
here is a still picture of the buff tailed bumblebee. You see the tail not clean white,
but a sort of dirty yellowish colour. And finally, here's the other black and yellow with three
yellow stripes and a white tail. That's the garden bumblebee taken by my uncle.
And finally, we managed to get some decent footage of this queen common Khadar
bee. She's got a lovely gingery thorax and quite a gingery abdomen,
certainly with no white tail. So that's the common car to be queen.
So let's think about the lifecycle of the bumblebees. And they all have a pretty similar lifecycle.
They come out now from hibernation in the spring and they're looking to found their colonies. They're not looking
for mates. They already did that. They found a male at the end of last summer before they
went into hibernation. And they can store that sperm all the way through the winter
and use it now in their new colonies. Now, what they're doing, as I said, the first generation
are going to retire is the first generation of workers, and they'll have to brood that generation themselves
and feed them. But as soon as those workers emerge and can go off and forage for themselves,
the queens will no longer leave the colony. They'll stay there laying eggs
and producing more workers and sort of ordering the others around. And the workers will be going off and foraging.
And that's when you start to see a lot more bumblebees. You'll see the populations really building up through the summer.
Now, bumblebees have a Albie's belong to. A group called the Hymenoptera,
and that's the bees. Ants and wasps, and they have some really strange mechanisms
for determining sex. So at the end of the summer, once the colonies become very large,
the colonies will switch, the females will switch to producing the males and
the new queen. So everything will change or stop producing workers and now produce the new
queens and the male. So how do they do that? So one way they do that is through
the sex determination mechanism. So remember, we said with the fertilises that for most sexual
organisms you have two copies of the instruction manual inside your genome.
And we call that being deployed. So we are deployed organisms. And when
we want to make new offspring, we have to, first of all, separate the two copies into
one. So for an egg cell or a sperm cell only gets one copy of the manual. And then
when egg and sperm cell fuse, we restore the deployed number. Now,
in space and was something really strange happened. So if the female simply lays
an egg, which is unfertilised and he has a single copy of the manual that
will develop into a male. But if the egg is fertilised and it's a diploid
embryo, then it will become a female. And that's unique to that group is a really strange
system. And we call them haploid deployed because the males are haploid and the females
are deployed. Now, the workers are all female and so are the new queen. So
how does that work out? How do you decide whether you are going to become a worker or a queen?
And that is under the control of the queen. So she releases chemicals inside
the nest that suppress the ovaries of the work of females, which means that they
can't have offspring of their own. And if that starts to break down, and it often does
at the end of the summer and all hell can break loose in the colony and the workers can start to rear
their own offspring. And that does happen. So the bumblebees seem like this very
calm and ordered system. But actually, there's quite a lot of tension and conflict within the colony.
And that starts to emerge as the season goes on. Well, we've spent the last week
chasing after these queen bumblebees and we've really found it hard to get some of the Monville.
We've really noticed that the car dibby that gingery bee. That's the one that's really quite friendly.
We'll let you approach. The others are much more difficult. I'm not sure whether it's because they're still really actively
looking for less. So they won't settle anywhere. Or whether they just are actually very skittish.
So we're sort of frightened of bees. But it seems like they're pretty frightened of us. So if you're having if you're
trying to get some photographs of queen bees, I hope you have a better job than I managed
anyway. Until next time. That's the end of this episode. So happy hunting for queen bees.
And we've found a bit of a casualty here. This is a queen of, I think,
the buff tailed bumblebee and she is in the grass there
and she's quite cross about something. And now I've made her rather irate. Oh, it's all right.
So the fact that they failed to heed that.