0:00

I'm Dr Karl, coming to you from

0:02

the lands of the Gadigal people of

0:05

the Eora Nation. I acknowledge Aboriginal and

0:07

Torres Strait Islander peoples as the first

0:09

Australians and traditional custodians of the lands

0:11

where we live, learn and work. G'day,

0:16

Dr Karl, University of Sydney, Shedlows of

0:18

Science, talking with somebody who is allergic

0:20

to an animal that they make their

0:22

income from. We're

0:24

talking about a creature that is

0:26

going to potentially destroy, or at least

0:29

severely impact, the Australian agriculture industry, one

0:31

that we're incredibly dependent on. So I'm

0:33

talking with Dr Emily Remnant. That's right.

0:36

And we're talking about bees. I'm a bee

0:38

geneticist. Bee geneticist. Yes. So

0:40

they have chromosomes? They sure do. They

0:43

got DNA longer or shorter than ours?

0:46

They have much smaller genome

0:48

than humans, tenfold smaller. Tenfold

0:50

smaller. Yeah, so there's 300

0:52

megabases instead of three. Billion.

0:55

Yeah. So we're talking about

0:58

the Varroa mite, which has landed in Australia in

1:01

2022. It's now

1:04

near the end of 2023. It's nearly 18 months

1:06

ago, yeah. And this could

1:08

do devastating things. And

1:11

you're allergic to bees? Yes, well. You know you

1:13

work with them? Yes, and obviously that's

1:15

a bit of a job hazard. I didn't start

1:17

out this way. So I've been at the uni

1:19

for about 10 years. And

1:22

back in 2013, I was getting

1:24

stung happily. Not quite happily, but.

1:26

But with no bad reactions? Sort

1:28

of like, I'm stung, ouch, that's annoying. Yes,

1:31

you know, a bit of local swelling, which

1:34

slowly got worse. And at some

1:36

point it was starting to swallow

1:38

all over all the other places

1:40

of my body, like face, feet.

1:42

So I got checked and I

1:44

was getting too sensitive to

1:46

the venom. So I had to stop working

1:49

with bees and I underwent immunotherapy for five

1:51

years. Is that when they give

1:53

you micro, pico, nano amounts

1:55

or something? You start off with, say,

1:57

one one thousandth of a bee sting. They

2:00

inject that into your arm and they monitor you for an

2:02

hour. Then after a few weeks

2:04

you sort of progress up to get 1B

2:07

equivalent. So I was

2:09

getting stung by a B via syringe

2:12

for once a month for five

2:14

years. Once a month, every

2:16

month, for five years. You

2:19

didn't go to the full anaphylactic reaction where you were

2:21

throat-swallowing the car? No. You were

2:24

heading down that? I was, yes. You have to carry

2:26

an EpiPen? I did carry an EpiPen for a while.

2:28

Now that I am considered to be safe to

2:30

be stung but not safe enough to open up

2:32

a B hive. I think

2:34

it's a dose thing. If I was to get stung

2:36

10 times it might not be so great but one

2:38

sting in the park would be fine. Probably.

2:41

Wow, I'd be lucky to live in a country where we

2:43

can have that medical therapy. Absolutely, yes. It

2:45

was all covered by Medicare. So looking at

2:48

the big picture with bees, I've heard various

2:50

statistics on how they provide 100% or 1%

2:52

or they help with our human agriculture. So

2:56

can you give me sort of like a vague

2:58

figure worldwide of how much they help us and

3:01

we're not paying them at all by the way

3:03

for this. No. So

3:05

bees are variously quoted to contribute to

3:08

agriculture. About one third of all food

3:10

we eat is enhanced

3:12

by pollination from honey bees.

3:15

They may not be the only thing that

3:17

can pollinate that crop but they're the best

3:19

thing that can pollinate those crops. So they

3:22

really enhance the quality and the yields of

3:24

a lot of fruit, vegetables, nuts, some seeds.

3:27

That eventually amounts to increasing the variety

3:29

of the food that we actually consume.

3:31

So grains aren't pollinated

3:33

by bees but I think life would be

3:35

pretty boring if that's all we were able

3:37

to eat. So all the yummy stuff, the

3:39

fruits and veg and all the nuts, seeds

3:41

and other things. So these bees

3:43

are a potential risk of food. Firstly in China,

3:46

in some places they're doing human

3:48

pollination and it's secondly in Australia they're

3:50

out of our, I think it's

3:52

700,000 hives. One

3:55

third get put onto semi-trailers and

3:57

taken to border of New

3:59

South Wales. Victoria and South

4:01

Australia to pollinate canola.

4:08

Yes so the almond pollination happens

4:12

every August. It's about a third of all hives in

4:14

the country, a truck to this

4:16

small region sort of at the junction between South

4:18

Australia, Victoria and New South

4:20

Wales. It's the biggest livestock movement in the

4:22

country and that is one issue

4:25

surrounding the most recent event that we've had with

4:27

Faroah in that this

4:30

migratory behavior of pollination industries

4:33

is a big threat for the spread of

4:35

parasites and diseases. So on

4:37

one hand these bees contribute mightily

4:39

to one-third of all the food we eat

4:42

and we don't pay them, they don't have

4:44

a union, all that sort of stuff. But

4:46

on the other hand some

4:48

sort of infectious agent has come into Australia

4:51

after we've been free of them

4:53

for a long time. Did the

4:55

Faroah might arise recently or has

4:57

it been around in all of

4:59

human recorded history 5,000 years or

5:01

whatever? So the Faroah might are

5:03

a recent parasite of our

5:05

Western honey bee Apis mellifera so that's

5:07

the species we use the European bee

5:10

that was brought to Australia pollination. So

5:12

we don't use native Australian honey bees,

5:14

is there year to year low or

5:16

something? We do use native bees

5:18

for some tropical crop so we

5:20

have nine different species in Australia

5:22

that can pollinate some crops but

5:25

they aren't able to pollinate a lot

5:27

of crops especially in the cooler regions.

5:29

They're much smaller and also

5:32

their temperature range is a bit more

5:34

restricted for warmer temperatures. So we

5:36

do rely on the Western or European honey bee

5:38

for all of those things. And how

5:41

do you pronounce it?

5:43

Apis? Apis mellifera. M-E-L-L-I-S-E-R-A.

5:45

Okay so Apis mellifera

5:47

is the standard used

5:50

in Western society to

5:52

give us a bit of honey but also to pollinate

5:55

like crazy. That's right and this species is one of,

5:57

depending on who you talk to, about 11 Apis. species

6:00

around the world. There's quite a few especially throughout

6:02

Asia. This Western

6:06

honeybee that we frequently use has

6:08

not had mites like the Varroa

6:10

mite which we're talking about for

6:12

its entire life history but these

6:14

mites came from another apis species

6:16

in Asia, apis serana. These

6:19

mites were brought into contact with apis

6:21

mellifera as people moved the beehives around

6:24

and their mites saw this new host and thought, oh

6:26

you look tasty I'm going to jump over and see

6:28

if I can reproduce on you and over

6:31

the last century they managed to shift

6:33

the host over to these bees and via

6:36

hive movements around the world they spread throughout the

6:38

rest of the world as well. You said over

6:40

the last century so it's not something that's been there

6:42

for many thousands of years just a recent thing. Yeah,

6:45

a recent host shift and that has been

6:47

part of the problem is that Western bees

6:49

have not been able to deal with this

6:51

new parasite because it's such a new threat

6:53

to them so they don't have any behavioural

6:56

adaptations to protect themselves against

6:58

it. What does

7:00

the mite look like? It's

7:02

about the size of a sesame seed, the

7:05

Varroa mite and relative to the

7:08

bee that's about one-third of its thorax so

7:10

if you think of the insect has a

7:12

little head it has sort of medium thorax

7:14

and a big fat abdomen and

7:17

the thorax region the mite takes about one

7:19

third of it. So if you think of

7:21

our back of a human it's like having

7:23

a little mini monkey hanging off your back

7:25

and sucking out your fat. A

7:28

bagel is one thing that I've heard people refer

7:30

to, the size of a large bagel or a

7:32

big donut or something that's about the same size.

7:34

I'm just thinking the middle image of me

7:36

having a bagel sized creature stuck to my

7:38

chest. Feeding on you instead of you feeding

7:40

on it. Now what they talk about something

7:42

I wasn't aware of in bees called a

7:44

fat body. Can you tell me? I have

7:46

no idea. So in the bee

7:48

they have organs like we do and

7:51

they have what's called a fat body

7:53

it's basically their liver and it's for

7:55

the fat body because it's majoritivly made

7:57

up of fatty tissue. which

8:00

is delicious to the mite. So the mite

8:02

basically will attach to the abdomen which is

8:04

the lower part of the body where the

8:06

fat body is and it will suck those

8:08

fat cells out and digest them and eat

8:11

them. Is the fat body located in one place

8:13

like our liver or is it just sort of

8:15

spread over the entire thorax like a thin layer?

8:17

It's mostly throughout the abdomen. It's sort

8:19

of quite mushy. I've seen it when

8:21

I've dissected it out. Really?

8:23

Which is sort of this white cloud

8:25

of tissue but it is

8:27

pretty contained to the abdomen of the bee. It

8:30

does the same in some ways as an equivalent job to

8:32

our liver which is processing

8:34

foods, detoxifying, making chemicals,

8:37

recycling stuff. Absolutely. It's

8:40

kind of essential. Yep. It's pretty essential. So when

8:42

the mites feed on that tissue it depletes

8:44

the size of the bee as it emerges

8:47

and it also causes their body weight

8:49

to be smaller and they're just malnourished

8:51

and don't tend to live as long

8:53

as a normal bee would. So

8:55

when a bee gets attacked by

8:57

the varroa mite its life

8:59

span is shortened. That's one factor

9:02

and it's not just the fact that the mite

9:04

feeds on its nutritious tissues. It's

9:07

also the viruses that a mite can

9:09

spread. So it acts like a vector

9:11

for disease. So similar

9:13

to a mosquito biting off and transmitting

9:15

dengue fever or something like that, the

9:18

mites also transmit viruses between bees

9:21

which can cause major issues for

9:23

a colony. So I'm guessing in

9:25

humans we had the plague and there were

9:27

the rats and the rats carried a flea

9:29

and the flea carried a bacteria

9:32

called Eucinia pestis and that was what

9:34

caused the plague. What are the viruses?

9:36

There are a few viruses that bees

9:39

suffer from. Lots of these are pre-mung

9:41

and don't crop up at all only

9:43

seasonally. Some of these viruses cause the

9:45

larvae that are growing in the hive

9:47

to die early. Other

9:49

viruses cause the queen cells

9:52

to turn black. There's a virus called black

9:54

queen cell virus. So when they re-rear in

9:56

the queens they don't emerge and they turn

9:58

black. become

10:00

a queen that's being fed

10:02

the special royal jelly. That's

10:05

right and sometimes the viruses can

10:07

disrupt that process. There's one virus

10:09

that does that and there's

10:12

one particular virus around the world associated

10:15

with mites called deformed winged virus.

10:17

Deformed wing. Maybe have a guess what you think

10:19

that might do to the bees. Would that be the feel

10:21

of their ability to travel? That is one

10:24

typical symptom. It's actually a badly named

10:26

virus because you can carry deformed winged

10:28

virus without having deformed wings. This virus

10:31

is particularly associated with varroa throughout the

10:33

world and the parasite and the virus

10:35

together are what causes colony losses.

10:38

So the mite is

10:40

bad enough but if you have the mite with

10:42

any one of a bunch of viruses that can

10:44

then lead to colony. I don't like

10:46

using the term colony collapse disorder. That's also

10:49

a bit of a term that carries some

10:51

weight but colony declines is

10:53

one way to put it so a

10:55

hive will have varroa mites. If

10:57

the virus is also present over

10:59

time that virus will increase to really high

11:02

levels in the presence of the mite and

11:04

then the colony will eventually die. Let

11:06

me ask you about colony collapse disorder which

11:08

you don't want to use because I heard

11:11

this phrase many times over a decade.

11:13

Is it a decade? Probably longer.

11:16

So what was it? What was

11:18

the cause if there is one known and where are

11:20

we with regard to fixing that before we come back

11:22

to the varroa mite? The colony collapse was really

11:24

used in the early 2006 maybe when it first

11:26

came commonly used.

11:30

This is sort of a collection of different

11:32

symptoms that people would noticing in their bees

11:34

where you would open a hive and all

11:37

the adults are gone. The

11:39

adults are gone? Yes. So

11:41

a hive contains the whole family. It's got the

11:43

queen which is the mom, it's got the drones

11:46

which are the boys and the workers which are

11:48

the females and these workers are growing all the

11:50

young baby bees so little larvae and pupae that

11:52

are growing in the hive. The

11:54

drones, the males are kept around

11:57

only until they fertilise the queen and they're booed out to

11:59

die. something. Yeah the mating system

12:01

of the bee is pretty fascinating actually

12:04

that's a different story but the drones

12:06

are produced around mating season around springtime.

12:08

Well each springtime. Yeah. Even if the

12:10

Queen is still alive. They don't mate

12:12

with the Queen in their own height. Fly out

12:14

once a day to what's called a

12:16

drone congregation area which is an open space. We've

12:19

got one of them on campus. The University

12:21

of Sydney. We do. Well it's so close to the centre of

12:23

Sydney. We do. They're anywhere

12:25

that's sort of a big open area

12:27

with some surrounding trees. One of our

12:29

ovals on campus has a drone congregation

12:32

area and the drones fly out once

12:34

a day and they scan for Queens from other

12:36

hives. What? They're checking out the action man.

12:38

Yeah it's like yeah they're down to the

12:40

nightclubs for that well it's in the afternoon

12:42

it's about two o'clock. Presumably there is

12:44

a Queen that has not yet

12:47

mated in a hive? The

12:49

Queens that haven't yet mated we call them the

12:51

Virgin Queens they will fly out at that time

12:53

of day and they will be eagerly pursued by

12:56

any drones in the area and

12:58

they mate in the air and the

13:00

drones will mate with the Queen once

13:02

and then they die. That can happen

13:04

about 20 or 30 times

13:07

for the one Queen so she'll mate with

13:09

the drone the drone dies and then another

13:11

drone will mate with her as she flies

13:13

around that drone congregation area. When

13:16

do the drones die? Like immediately after

13:18

mating? So the act of mating

13:20

causes the abdomen to explode. Yes.

13:22

I had this wrong

13:24

I thought the drones got booted out of the hive

13:26

because their job was done but you're saying the

13:29

act of mating? Yep when they reach

13:31

the Queen they attach to her and they

13:33

avert their endophilus which is the polite word

13:36

for their drone penis and

13:38

that causes their abdomen to puncture and

13:40

so once they've mated they basically drop

13:42

to the floor dead so they

13:45

have really achieved their goal in life which is

13:47

to pass on their genetic material to the next

13:49

generation. And it's like sperm?

13:51

Same thing as humans. Like

13:54

a little tadpole thing with

13:56

mitochondria to power it. Yeah

13:58

look I think there is mitochondria. And

14:00

how many sperm are we going to know? Lots

14:02

and lots. But the queen actually mates with

14:05

20 or 30 drones in one mating flight.

14:08

So that would be like 10 minutes or an

14:10

hour or several hours? In the space of about half

14:12

an hour. A couple of minutes each. Yeah.

14:15

Come on drone, you did the next one. So

14:18

that gives her a variety of potential

14:20

genetic material. Exactly. That's

14:22

right. So her goal is to

14:24

mate widely so she has a robust

14:26

population in her hive of different genotypes,

14:28

different genetic lineages that will each have

14:30

certain strengths or weaknesses. So a bit

14:32

of diversity in the hive to help

14:35

keep that hive strong. And

14:37

she stores the sperm in her sperm

14:39

storage organ which is the spermotheca and

14:42

that lasts for the rest of her life.

14:44

Which is five or six years or something? That's

14:46

about the sort of maximum you see. That's about

14:48

maximum, is it? My former mentor Ben Aldroyd

14:51

said he had a queen for nine years once.

14:54

That's the upper end. But most

14:56

beekeepers would probably re-queen their hives

14:59

every year or two. What do

15:01

you re-queen a hive? Yeah, so you catch the queen,

15:03

you say thanks for your service and going to

15:05

put in a new queen now because the younger

15:07

the queen, the more offspring they lay

15:09

and the stronger the hive. But

15:12

that means that there's a certain period before

15:14

that young queen has mated where

15:16

she's not producing babies. Yes. So

15:19

the virgin queens will emerge and

15:21

within a few days they will take a

15:23

mating flight and then they return to their

15:25

original hive. And

15:27

then there's a tussle. So often what would

15:29

happen is you'd have the old queen dive

15:31

for some reason. She gets squashed by the

15:34

beekeeper or something else takes out

15:36

the queen and then the colony will

15:38

rear the virgins after the queen

15:40

has gone. It's not always

15:42

a case of one queen remaining in the

15:44

hive and the younger queen trying

15:47

to usurp her. Sometimes the queen has

15:49

died. The queen might have swarmed so

15:51

she might have decided to pack up

15:53

and leave and start a new colony

15:55

and that leaves the virgin queens to

15:57

replace her there after they're mated. But

16:00

you can only have one queen per hive, have

16:02

my rotor wrong on that? Yep, that's usually

16:04

what happens. I think there are some places

16:07

where you can experiment with putting in a

16:09

couple of queens and keeping them separate from

16:11

each other, but that's not commonly done here.

16:14

So we went down a little bit

16:16

of a diversion there. Thank you

16:18

for correcting my misapprehension, because I really thought that

16:20

the drones, having made it, went back to the

16:22

hive, hung around, drank a few beers. And the

16:24

rest of the hive said, we were thinking you

16:26

off you go. The drones that are a

16:28

main in the hive were the ones that didn't

16:30

manage to mate. So they would probably come back

16:32

home, say I'll try again tomorrow. And eventually the

16:34

hive do get a bit sick of the little

16:36

freeloaders, and they kick them out at the end

16:38

of the season. There's three sort

16:41

of gender-y, sexy things happening. There's

16:43

a fully fertile female who's

16:45

the queen. Yep. There's

16:48

a very small number of males who once

16:50

they've done their job are booted out. And

16:52

then there's a lot of, is

16:55

it fair to say they're sterile females?

16:57

Yeah, they are. The work

16:59

force, thousands of females, up to 40, 50,000

17:01

in each hive. Wow.

17:05

They are functionally sterile, is

17:07

what we say, because if the

17:09

queen was to die, while

17:12

they can't go out and mate,

17:14

they can activate their ovaries and

17:16

lay unfertilized eggs. Those unfertilized eggs

17:19

can become male bees. So honey

17:21

bee sex determination is based on whether

17:23

the egg has been fertilized or not.

17:26

So even though they're sterile,

17:29

they can lay all

17:32

of them, or just some of them under

17:34

certain circumstances. Only when there's no queen, usually.

17:36

When there's no queen, something happens, a pheromone

17:38

is released or something that changes. Yeah, so

17:40

the queen is constantly producing a pheromone. So

17:42

when that pheromone is no longer present, the

17:45

bees know that something's wrong with the hive,

17:47

and they go, where's our queen? There's

17:50

two things that happen. One is, if there's

17:52

some eggs already laid by a queen that

17:54

are fertilized, they think, I'm going to make

17:56

a new queen, so I'll feed those eggs

17:58

royal jelly. It's official royal jelly. which

18:00

is epigenetics. But if we

18:03

don't get new eggs in the hive and

18:05

there's no chance of re-queening that way, the

18:07

workers then say, okay, what are we going

18:09

to do? We're going to activate our own

18:11

ovaries and try and lay eggs. But because

18:14

they haven't mated, those eggs don't get fertilized

18:16

and they become more. The last-ditch attempt at

18:18

saving their DNA and passing it on is

18:20

to produce some worker-produced

18:23

runes. But the ones who

18:25

do all the work are females, so really

18:27

they want females. Yeah, the females are

18:29

really what keep the hive going. So a hive

18:31

would pretty much be on its last legs at

18:33

that stage if there was no queen and no

18:36

chance of re-queening. We still

18:38

haven't gone deeply into the

18:41

varroa mite. Can I ask you to

18:43

come back and we do a part

18:45

two? Of course. Okay, so that is

18:47

now the official ending of part one,

18:49

Dr. Emily Remnant, R-E-M-N-A-N-T. How

18:52

can people follow you if they want to

18:54

become your student because you're at the University

18:56

of Sydney and you follow you and you'll

18:58

find working stuff? So you can

19:00

always check out our website which

19:02

is www.b-lab.sydney.edu.au. So

19:04

that's B-E-DASH, not an underscore, a dash. Yep.

19:10

Then L-A-B. Yep, dot

19:12

Sydney.edu dot AU. And

19:15

then we could also email

19:17

me. My name is

19:19

Emily dot Remnant at Sydney.edu dot

19:22

AU. Or if you are on

19:24

social media, I have a Twitter account

19:27

at MZRemz, one word. M-Z-Remz.

19:29

That's right. E-M-S-Y, R-E-M-S-Y. R-E-M-S-Y.

19:33

Thank you very much for part

19:35

one. Thank you, Dr. Carl. Forty

19:38

years after my very first story on

19:40

climate change, I'm still on the case.

19:43

But now I've decided to write a

19:45

book on it. It's

19:47

Dr. Carl's little book of climate change

19:49

science and it will explain how we

19:51

got into this mess and how we

19:53

can get out of it. You'll

19:56

find out who did the early research

19:58

into climate change and then... We've spent

20:00

billions of dollars trying to cover

20:02

it up and why they did

20:05

that? We'll find out now. Greenhouse

20:07

gases trap 400,000 Hiroshima atom bombs

20:09

worth of heat every day and

20:12

invest how we

20:14

can stop and even reverse global warming.

20:16

Dr Karl's little book of climate change

20:19

science. Get this book while it's not

20:21

hot. Yes, we

20:23

can help stop global warming and improve

20:25

the lives of current and future generations.

20:28

It's available as a paperback, e-book

20:30

and audio book from your local

20:33

bookshop, library or online. Shirtloads of

20:35

science is washed, spun and aired

20:38

by the University of Sydney.