The dance of the dung beetle Marcus Byrne

this is food and what I want to do today

is share my passion for poo with you

which might be quite difficult but I

think what you might find more

fascinating is the way these small

animals deal with poo so this animal

here has got a brain about the size of a

grain of rice and yet it can do things

that you and I couldn’t possibly

entertain the idea of doing and

basically it’s all evolved to handle its

food source which is dumb so the

question is where do we start this story

and it seems appropriate to start at the

end because this is a waste product that

comes out of other animals but it still

contains nutrients and there are

sufficient nutrients in there for dung

beetles basically to make a living and

so dumb beetles eat dung and their

larvae are also dumb feeders they are

grown completely in a ball of dung

within South Africa we’ve got about 800

species of dung beetles in Africa we’ve

got 2,000 species of dung beetles and in

the world we have about 6,000 species of

dung beetles so according to dung

beetles dhoni is pretty good but unless

you’re prepared to get dung under your

fingernails and route through the dung

itself you’ll never see ninety percent

of the dung beetle species because they

go directly into the dump straight down

below it and then they shuttle back and

forth between the done at the soil

surface and a nest they make underground

so the question is is how do they deal

with this material and most dung beetles

actually wrap it into a package of some

sort ten percent of the species actually

make a ball and this fall they roll away

from the dong sauce usually bury it at a

remote place away from the dung source

and they have a very particular behavior

by which they are able to roll their

balls so this is a very proud owner

at the beautiful dung ball you can see

it some mail because he’s got a little

hair on the back of his leg there and

he’s clearly very pleased about what

he’s sitting on there and then he’s

about to become a victim of a vicious

smash-and-grab and this is a clear

indication that this is a valuable

resource and so valuable resources have

to be looked after and guarded in a

particular way and we think the reason

they roll the balls away is because of

this because of the competition that is

involved in getting hold of that done so

this dump at was actually well it wasn’t

done about 15 minutes before this

photograph was taken and we think it’s

the intense competition that makes the

beetles so well adapted to rolling balls

of dung so what do you better imagine

here is this animal here moving across

the African felt its head is down it’s

walking backwards it’s the most bizarre

way to actually transport your food in

any particular direction and at the same

time it’s got to deal with the heat this

is Africa it’s hot so what I want to

share with you now are some of the

experiments that myself my colleagues

have used to investigate our dung

beetles deal with these problems so

watch this people and there’s two things

that I would like you to be aware of the

first is how it deals with this obstacle

that we’ve put in its way see there’s a

little dance and then it carries on in

exactly the same direction that it took

in the first place Neil Vance and then

heads off in a particular direction so

clearly this animal knows where it’s

going and it knows where it wants to go

and that’s a very very important thing

because if you think about it you’re at

the dung pile you’ve got this great big

pies that you want to get away from

everybody else and the quickest way to

do it is in a straight line so we gave

them some more tests to deal with and

what we did here is we turned the world

under there

feet from what response so this animal

has actually had the whole world turn

under its feet it’s turned by 90 degrees

but it doesn’t flinch it knows exactly

where it wants to go and it heads off in

that particular direction so our next

question then was highly doing this what

are they doing there was a culet that

was available to us was it every now and

then they climb on top of the ball and

they take a look at the world around

them and what do you think they could be

looking at is a climb on top of the ball

what are the obvious cues that this

animal could use to direct its movement

and the most obvious one is to look at

the sky and so we thought now what could

they be looking at in the sky and the

obvious thing to look at is the Sun so a

classic experiment here in that what we

did is removes the Sun what we’re going

to do now is shade the Sun of the board

and then move the Sun with a mirror to a

completely different position and look

at what the beetle does does a little

double dance and then it heads back in

exactly the same direction twins in the

first place what happens then so clearly

they’re looking at Sun Sun is a very

important human scarf for them the thing

is the Sun is not always available to

you because at sunset disappears below

the horizon what was happening in the

sky here is that there’s a great big

pattern of polarized light in the sky

that you and I can’t seize the way our

eyes are built but the Sun is that their

horizon over here and we know that when

Sun is at the horizon sets over on this

side there is a north-south a huge pass

way across the sky of polarized light

that we can’t see but the Beatles

conceived so how do we test that well

that’s easy what we do is we get a great

big polarization filter pop the beetle

Indonesia

and the filter is at right angles to the

polarization packages sky beeping comes

out from underneath the filter and it

does right hand to him because it comes

back under the sky that it was

originally it orientated too and then re

already takes itself back to the

direction it was originally going so

obviously Beatles can see polarized

light okay so what we’ve got so far is

what a Beatles doing they’re rolling

balls how they doing it well they

rolling in them in a straight line how

they maintaining it in a stroke

particular straight line well they’re

looking at celestial cues in the sky

some of which you and I can’t see but

how do they pick up those celestial cues

that was what the interest to us next

and it was this particular little

behaviors our dance that we thought was

important because look it takes her paws

every now and then and then heads off in

the direction that it wants to go in so

what are they doing when they do this

dense have far can we push them before

they will reorient eight themselves and

in this experiment here what we did was

we force them into a channel and you can

see he wasn’t particularly forced into

this particular channel and we gradually

displaced the beetle by 180 degrees

until this individual ends up going

exactly the opposite direction that it

wanted to go in in the first place and

let’s see what his reaction is because

he’s headed through 90 degrees here and

now he’s going to when you end up down

here is going to be a hundred and eighty

degrees in the wrong direction and see

what his responses does a little dance

turns around and heads beckons he knows

exactly where he’s going he knows

exactly what the problem is and he knows

exactly how to deal with it and the day

is this transition behavior that allows

them to reorient eight themselves so

that’s the dense but have to spending

many years sitting in the African bush

watching dung beetles on nice hot days

we notice that there was another

behavior associated with the dance

behavior every hand then when they climb

on top of the ball they wipe their face

and you see him do it again now he’s not

know what could be going on here the

clearly the ground is very hot too when

the ground is hot they danced more often

and when they do this particular dance

they wiped the bottom of their face and

we thought that it could be a

thermoregulatory behavior we could we

thought that maybe what they’re doing is

trying to get off the hot soil and also

spitting on to their face to cool their

head down so what we did was design a

couple of arenas one was hot one was

cold we shaded this one we left that one

hot and then what we did was we filmed

them with a thermal camera so what

you’re looking at here is heat image of

the system and what you can see here

emerging from the poo is a cool dung

ball so the truth is if you look at the

temperature over here don’t is cool

so all we’re interested in here is

comparing the temperature of the beetle

against the background so the background

here is around about 50 degrees

centigrade the beetle itself on the ball

are probably around about 30 to 35

degrees centigrade so this is a great

big ball of ice cream that this beetle

is now transporting across the hot felt

it isn’t climbing it isn’t dancing

because its body temperature is actually

relatively loads about the same as yours

and mine and what’s of interest here is

that little brain is quite cool but if

we contrast now what happens in a hot

environment look at the temperature of

the soil it’s up around 55 to 60 degrees

centigrade watch how often the beetle

dances and look at its front legs their

roaring Lee hot so the ball leaves a

little thermal shadow and the beetle

climbs on top of the ball and wipes its

face and all the time it’s trying to

cool itself down we think and avoid the

hot sand that it’s walking across and

what we did then was put little boots on

these legs because this was a way to

test it’s a legs were involved in

sensing the temperature of the soil and

if you look over here with boots they

climb onto the balls far less often when

they had no boots on so we described

these as cool boots it was a dental

compound that we used to make these

boots and we also pull down the dung

ball so we were able to put the ball in

the fridge gave them an icicle dung ball

and they climbed onto that ball far less

often then when they had a hot ball so

this is called still ting it’s a thermal

behavior that you and I do if we cross

the beach we jump onto a hop onto a

towel somebody else’s towel sorry I

jumped onto your tail and then you

scuttle across on somebody else’s to

hell and you in that way you don’t burn

your feet and that’s exactly what the

beetles are doing here however there’s

one more story I’d like to share with

you and that’s this particular species

it it’s from a genius called soma

there are sir

species in the genus and they have a

particular behavior that I think you

will find interesting this is a dung

beetle watch what he’s doing Tran you

spot the difference they don’t normally

go this slowly it’s a slow motion but

it’s walking forwards and it’s actually

taking a pellet of dry done with it this

is a different species in the same genus

but exactly the same foraging behavior

there’s one more interesting aspect of

this dung beetles behavior that we found

quite fascinating and that’s that it

forages and provisions are nest so watch

this individual here and what he’s

trying to do is set up a nest and using

like his first position but he comes up

with a second position and about 50

minutes later that nest is finished and

he heads off to forage and provision at

a pile of dried dung pellets and what I

want you to notice is that outward path

compared to the homewood path and

compare the two and by and large you’ll

see that the homewood passes far more

direct than that outward path on the

outlet pass he’s always on the lookout

for a new blob of dumb on the way how he

knows where home is and he wants to go

straight to it the important thing here

is that this is not a one-way trip as in

most done beetles the trip here is

repeated back and forth between a

provisioning site and a nest site and

watch you’re going to see another South

African crime taking place right now

his neighbor steals one of his dumb

Phillips so what we’re looking at here

is a behavior called pass integration

and what’s taking place is that the

beetle it’s got a home spot it goes out

on a convoluted path looking for food

and then when it finds food it heads

straight home it knows exactly where it

turn these now there’s two ways it could

be doing that and we can test that by

displacing the beetle to a new position

when it’s at the foraging site if it’s

using landmarks it will find its home if

it is using something called path

integration it will not find its home it

will arrive at the wrong spot and what

it’s doing here that’s using pass

integration is its counting its steps or

measuring the distance out in this

direction it knows the bearing home and

it knows it should be in that direction

if you displace it it ends up in the

wrong place so let’s see what happens

when we put this beetle to the test with

a similar experiment so here’s our

cunning experimental he displaces the

beetle and now we have to see what is

going to take place what we’ve got is a

burrow that’s where the forage was the

foragers been displaced to a new

position if he’s using landmark

orientation he should be able to find

the Burrow because they’ll be able to

recognize the landmarks around it if

he’s using a path integration then it

should end up in the wrong spot over

here so let’s watch what happens when we

put the people through the whole test so

there is there he’s about to head home

and look what happens

shame it hasn’t a clue it starts to

search for its house in the right

distance away from the food but it’s

clearly completely lost so we know now

that this animal uses pet integration to

find its way around and the callous

experimental leaves at top legs so what

we’re looking at here are a group of

animals that use a compass and they use

the Sun as a compass to find their way

around and they have some sort of system

for measuring that distance and we know

that these species here actually can’t

the stitch that’s what they used as an

odometer a step counting system to find

their way back home we don’t know yet

what dung beetles use so what have we

learned from these animals with a brain

that’s the size of a grain of rice well

we know that they can roll balls in a

straight line using celestial cues we

know that the dance behavior is an

orientation behavior it’s also

thermoregulation behavior and we also

know that they use a pat integration

system for finding their way home so for

a small animal dealing with a fairly

revolting substance we can actually

learn an awful lot from these things

doing behaviors that you and I couldn’t

possibly do thank you