International Design Contest
Art of Science: Walkin' After Midnight
Mind Reading: Dyslexia
FLOWERS Tally ho and all that. I'm Woodie Flowers, and welcome
to Scientific American Frontiers. Check out my outfit!
(V.O.) This is the classic fox hunt -- except, there's no
fox. The dogs are following fox scent laid down early this
morning. It's the modern version of an old English tradition.
Our first story takes us to the West Coast, to unearth a very
different fox tradition -- -- one that links Native Americans
of long ago with scientists of today. If it's a clear day
on Santa Catalina you can see Los Angeles just 22 miles to
the east. But to the west the view is the same as it was 2000
years ago when the Gabrielino people lived here. Native Americans
disappeared from the island long ago, but their culture is
not entirely lost. Today, archaeologists from the University
of California are reconstructing the ancient rhythms of life
SYNC All of this shell in here is refuse from their meals...
in other words, we're looking in somebody's garbage dump.
FLOWERS One man's garbage is Bill Howard's treasure. From
these fragments, he's piecing together a mosaic of the Gabrielino
SYNC These are what's left over from making tools. Some of
them are tools. Now this is a nice flake that's very sharp
and could be used for cutting vegetable material or hides
or cordage or each other.
FLOWERS As the archaeology team digs deeper they're finding
out what the Gabrielinos ate and what the island ecology was
like. Abalone shells are especially abundant in the 2000 year-old
layer...so abalone must have been plentiful and a food staple.
SYNC I love their diet...it's good eatin'. Do you know how
much abalone sells for a pound? Wonderful. A day in the life
of an Islander 2000 years ago would have been like this. In
the mornings, the community cast large fishing nets into the
kelp beds near shore. Of course the Gabrielinos would have
known the best fishing spots. While men fished offshore, women
and children gathered tasty tegula snails from the rocks.
At low tide abalone was easy to find and easy to harvest.
In the afternoons, when the stronger men returned from ocean
fishing, the community would gather to prepare the evening
meal. Here, the sharp stones were used to cut abalone or to
scale and clean fish. Stone tools were also used to cut vegetables,
or pound them. And it was here, around the cooking fire, that
families passed on the myths that shaped their religion. Finding
out about this spiritual side of life is one of the toughest
jobs for an archeologist.
SYNC Neato Alburito!...Thatís a prize...Oh that's incredible...Isnít
that gorgeous? That's why finding a clue like this is so exciting.
It's a hand carved pelican stone. Reverence for nature's creatures
was expressed in sculptures like these. Pelicans were respected
for their fishing ability. The whale was admired for its formidable
size and strength. The fox was esteemed as a quick and clever
survivor. But the islanders enjoyed a special relationship
with the fox. Fox bones show up, not in the garbage dumps,
but in ritual burial sites, where Dana Bleitz and her colleagues
found this complete skeleton.
SYNC One fox we found was buried in a very small hole, just
large enough for its body and it was capped by a stone. Underneath
the stone we found that the fox had his head up towards the
top and he was tightly flexed and his tail curved right up
towards his nose and his paws were crossed in front of him.
And he was very carefully placed in the pit that way. The
implications of finding ritually buried foxes is...it's really
exciting because we do get an insight into how the Indians
were perceiving these animals. Some fox rituals have survived
the centuries. Tony Romero, a Chumash dancer from Santa Ynez,
still performs an ancient fox dance. In this dance, Tony transforms
himself into the sly, tenacious creature of Native American
legend. The fox fleece on his head conceals his human form.
The fox is keen, cautious and sure footed. Nothing escapes
his sharp eyes. He leaves no stone unturned, no tree unexplored
in his determination to survive. Thousands of years ago Chumash
traders brought foxes to Catalina, where they were adopted
by the Gabrielinos. Ironically, the Gabrielinos are long gone
from this island.., the only living trace of their culture
here is the fox, who still roams Catalina. The fox is a true
survivor, but today even its presence here is being challenged.
NARRATION This island paradise has attracted a wave
of tourists and residents. They benefit the local economy,
but they also tax the environment. For example, the land around
these new luxury homes is inhabited by foxes. If the development
spreads it could overrun fox habitat. If home owners bring
disease, the foxes could be wiped out. So the Catalina Island
Conservancy has dispatched biologists to study the fox, and
to help ensure that its home here remains secure. Dave Garcelon
and Gary Roemer have their own fox ritual.
SYNC Mr. Fox! Each day they trap the animals. It's D5Yellow.
She's also collared. This female's bark is worse than her
bite. She's really a gentle creature. Bark..yes...growl...no
that's my finger. Trapping allows Dave and Gary to keep track
of population numbers and to perform medical check-ups. She's
not missing any hair around her teats so she may not have
a litter. Ok her eyes are normal. Since the island foxes have
never been studied before, no one knows how long they live.
I'm going to check her teeth, OK?...OK. To estimate the fox's
age, Gary checks the condition of her teeth.
OK upper incisors, all 6 normal. OK. Both upper canines are
normal. This fox has good teeth so she's probably young.
SYNC What about her age Dave, have I got her age? She's a
one. She looks like a one. OK.
NARRATION Dave and Gary need to learn about fox
behavior, so they plan to spy on this female. A radio collar
will help them follow her in the wild. They have to pay special
attention to the fit of the collar...too tight and it will
hurt the fox...too loose and it will fall off. Like most check-ups,
the hard part comes last...getting a blood test. Things go
a little more smoothly if you can't see the needle.
Yeah, you look like little red riding hood.
NARRATION The blood sample will tell the biologists
a lot about this fox's health, but it will also tell them
how she is related to other island foxes and how Vulnerable
she is to disease. Collecting this kind of baseline information
is a critical part of protecting the species.
BILL SYNC She was barren this year or maybe she lost the litter?...bark...she's
talking to us...one sync bark. Like bad tasting medicine,
this ritual is good for foxes, even if they don't enjoy it.
I think that's a fox expletive to you Gary. Now Gary can track
the fox he just collared. His antenna picks up her signal.
Where are you little girl? There she is. She's running down
through the canyon toward the vehicles. The fox knows she's
being followed.., so she makes it harder. But by keeping up
with her Gary finds out things...like where she hunts and
what she eats. After dark, this game of hide and seek becomes
more difficult, even dangerous. Foxes are nocturnal but biologists
aren't, so tracking becomes a real art.
Ones that are a little bit more skittish...you just have to
lay off of them more, and use a lot more signal interpretation.
You kind of get a feel for things after a while, you know,
you've just gotta be out there and kind of get a feel for
what the signal does and what the animal does and that kind
of thing. But lots of times you're wrong too."
NARRATION This is where Gary saw the fox. He marks
the spot with a flag so that he can find it the next day.
These are long sleepless nights. Gary's vigil continues until
dawn. The next day he returns to his marker. He takes compass
readings to record the exact location of last night's fox
on a map. Gary knows generally where the foxes live on Santa
Catalina, but tracking will pin down their habitat and range
more precisely. This yellow dot is where Gary left the marker.
As he follows the same female for a long time, the boundaries
of her territory become clear. By tracking many foxes he begins
to identify the key features of their environment. Foxes depend
on these grass patches to forage for insects. They frequent
burrows in search of squirrels and mice. They visit cactus
patches looking for edible fruits and often resort to berries
to supplement their diet. This research is teaching us what
the fox needs to survive on Santa Catalina. For now the population
is healthy. But will the fox continue to have what it needs?
Native Americans protected and provided for the fox 2000 years
ago. Now this is our responsibility.
20 years ago -- the first MIT engineering contest. It started
when a young professor named Woodie Flowers had his students
build machines and compete head to head. Woodie is now a famous
TV host, and his contest has become a world-wide phenomenon.
It's spread to the Tokyo Institute of Technology where students
learn the MIT hands-on approach. And it's come to universities
in Germany and in Britain. Now the best, the top ten from
each of the four countries, will meet in Boston for the World
Series of Engineering. This will be their playing field. Each
team will have a goal and a supply of ping pong balls. Their
task: in ten days, build a machine that collects the balls
and gets them to the goal. They can fling them, drive them,
roll them, you name it. Whoever gets the most in, wins. As
the students arrive, they are divided into teams. This competition
doesn't pit nation against nation -- each team has one member
from each country, and one of the goals is international cooperation.
Right away an obstacle becomes obvious. There is a different
color t-shirt for each of the ten teams -but they each get
an identical kit of parts. Motors, gears, springs, pneumatic
cylinders .... It's a collection of junk nobody but an engineer
My favorite piece is the blue stuff, this stuff, because you
can do anything to it. It's easy to cut. It drills nicely
and it's blue... You can do a lot of tricky things with it.
Not only listen to the music... I like this and I am making
like this...I like music. I don't know if I can use it but
I like it...But the parts are only raw materials -- what's
needed is a good idea.
And as the gray team brainstorms, they're seeing how important
communication is in engineering. Working together they're
getting a taste of the future -- and that's exactly why MIT's
Harry West organized the contest.
HARRY WEST Today and even more so in the future, engineering
is going to be an international business. Products are designed
by teams of engineers and those teams are made up of engineers
from all over the world. To be competitive you have to be
able work together as a team. The gray team is taking an important
step in developing teamwork. While it may look like they're
just out having a good time, they're also learning about each
Burkhard, the German member of the gray team, eagerly shares
his love of classical music with his British teammate Sarah.
Before college, Burk worked in a church. It was part of his
two years of national service that's mandatory for all Germans.
The experience means they come to America older and more mature.
And for Burk, the time has helped him put his music into perspective.
My favorite music, that's baroque music. You can compare with
to be an engineer because order is very important in the baroque
music, and also good ideas.
For the yellow team, understanding each other's culture begins
with food. Asako valiantly tries to introduce her teammates
to a concoction of rice, pickled plumb and seaweed. She is
a pioneer -- a woman engineer from Japan. There were just
a handful of women in her class in Tokyo. And she was the
only one to win a trip to America. The differences between
her and her teammates go beyond food. Asako was raised in
a traditional society, one that does not encourage independence,
especially for women. But Japan is westernizing -- and when
her college took up football, Asako became a manager. Now
her trip to America is exposing her to more provocative possibilities.
MIT women seem more independent. They can build machines by
themselves. In Japan, since there are so few women in engineering,
we are babied by our classmates.
NARRATION In the machine shop, where ideas come to life, the
other women feel right at home -- but not Asako. In Japan,
the men were always eager to help her. At MIT, she's getting
the chance to develop her own skills. Her team has decided
to convey the balls to the goal with a ramp. It's an obvious
choice -- fast and efficient, it's been a proven winner in
this year's national contests. With this design, the yellow
team is focusing on victory. But Asako is disappointed. The
ramp may win, but it's not very original. Despite her growing
confidence, she wasn't able to persuade her team to be more
It's an idea contest so I'd like to make a more creative machine.
But it's not just my machine, so I can't just change it. In
fact, throughout the shop, conformity is catching.
STUDENTS We're going to make a ramp... Push them down a ramp...
Down the ramp to the goal. The original strategy was a ramp..,
a ramp.., an unfolding ramp...
HARRY WEST When students work alone they can decide for their
own personal reasons, for their own personal criteria to come
up with a really outrageously creative design -- a design
that probably won't win but will show off their design talents
to their friends. But when they're working as part of a team,
I think there is a certain pressure to conform.
The gray team -- wrestling with exactly this dilemma -- is
meeting to pin down their priorities. Masaya, the Japanese
member, wants to try to win with a safe but sure design --
like the other teams. Burk argues for the opposite tack --
have fun with an innovative but risky design.
To win is very... important
But we have already won
We've all shown that we can build a ramp. Everybody's built
And we wanted to do something new and challenging.
BURK Our goal is to make action
The decision: innovation, with a flipper design. Masaya goes
along, though he's not happy. Their flicker isn't working
that well. But that's Okay. To be creative you have to take
risks. Matt, the American member of the gray team, is no stranger
to risk -- he likes zooming around at 120 mph. His grades
suffer because he has a habit of spending more time in the
pits than in the library. But this hands-on experience has
given him a practical education in engineering.
I've learned most of what I know about engineering in my garage.
Most of the stuff that I do on the machines for the 2.70 contest,
just common sense stuff, that I've seen on cars or something
Matt has the experience and the confidence to be creative.
And it's no surprise what he contributes to his team's design.
A car to disrupt the opponents. Let's just hope he's a better
driver on the race track. Already it's the night before the
contest. There's last minute scrambling to meet size and weight
restrictions, and of course, the finishing touches. With time
up, it's clear there's conformity on another issue -- neatness.
It's Contest time. The yellow team is up early and Asako is
nervous. Their opponents also have a ramp -- and a surprise
-- an attack vehicle. But the yellow team's prepared with
an impenetrable defense. They stop the attack vehicle dead
in its tracks. And on the offensive side, they've designed
a chopping arm to drive balls down the ramp -- it works flawlessly.
For their opponents, nothing works. It's a rout -- Asako's
team wins by a landslide. As the night goes on, it becomes
clear why ramps are a smart choice. They're the best way to
get balls to the goal. Now it's the gray team's chance to
show off their design. They're up against one of the few other
teams that doesn't use a ramp. Right away, there's trouble.
Inexplicably, the flicker is stuck on top of the balls. Then
Sarah has an idea. She tells Matt to bring the car over and
give a push, but it doesn't work. Meanwhile the opponents
dump truck is collecting balls and getting ready to deposit
them. For Matt, it's demolition derby time as he drives the
dumpster away from the goal. The defense is strong, but the
offense can't score. Their experiment in creativity won't
win the contest, but they're not disappointed.
SARAH It was luck. This was always touch and go. It was touch,
it wasn't go.
After three grueling rounds, the yellow team makes it to the
finals. No surprise, it will bc ramp against ramp. Just before
the starting buzzer, the yellow team spots a problem.
TEAM It's okay, it's okay.
It's not okay. Their ramp gets caught on the way. They try
freeing it with the chopping arm but to no avail. The red
team makes winning look easy. They are the world champions.
But winning is not really the point of this contest. It's
about understanding other cultures, communicating ideas, and
working together as part of a team. All these students have
taken a giant step into the international future of engineering.
FLOWERS These contests are spreading like wildfire - from
elementary schools to universities all over the world. That's
because they work! They teach physics, math, engineering -
and other things, like international cooperation. But most
of all, they link teaching to the real world. Here's what
I mean. This computer system is running one of the new engineering
packages. And it's great! If I were in one of these contests,
and wanted to scoop up balls, tip the scoop back quickly to
hold them in, then dump them out behind the machine - this
looks like a winner. Designing it on this took just a few
hours - and since the system automatically generates plans,
I should be able to build this thing. See, it looks just like
the one on screen, and it works the same way too - oops! It
won't swing all the way back. Now if I take the linkage apart
and reassemble it in the "dump" position, it looks like this.
But it won't swing from front to back. Even using a high tech
tool doesn't ensure good design. Unless you have hands-on
experience that teaches you what to look for, the computer
won't necessarily tell you what Mother Nature thinks of the
design. Mother Nature, you see, applies all of her rules all
of the time. And that's something you really learn from these
OF SCIENCE: WALKIN' AFTER MIDNIGHT
FLOWERS This time on the "Art of Science" we have something
a little different: a dance, by choreographer Thecla Schiphorst.
What's the science connection? Well, the dancers are animated
on a computer - but what really caught our eye is the way
it's done. Thecla and her colleagues at Simon Fraser University.
The dancers developed their own software, called "Life Forms",
that makes it easy to program the individual steps ... put
several figures on stage at the same time ... and even change
their relative movements in time and space. Now, for the first
time, a choreographer can see a dance before calling the first
rehearsal. And sometimes the animation itself can be a work
of art. So sit back and enjoy "Walkin' After Midnight"
Where was Uncle Somebody going to come from? Does anybody
remember? What state in the United States? ... Alex?
Washington. Now there are two Washingtons. Do you know the
difference between the two Washingtons?
Ah yes ... the one farthest away. Third grade ... and there's
so much to learn. Geography is just one of the subjects ten
year-olds have to master. And Alex is pretty good at it --
as he is at most things in school, from art to arithmetic.
Okay and what's that one?
Just Washington. Okay, if I pulled down the map of the United
States, could you come show me? First of all, Uncle Somebody
is coming from which Washington? Way up there - that is Washington
State. He's also got a knack for how things work -- so he
can help eight year-old Jimmy get the hang of driving. But
it's not geography or mechanics that's brought these kids
to Newark, New Jersey.
You press reverse down there and forward's there. And you
have to make a straight ... there ... and then press forwards.
JIMMY Nowadays soccer balls -- as well as the balls used in
some other sports -- are made from synthetic materials molded
into the correct shape. However, the balls used by professional
teams have always been made from leather panels stitched together
around a rubber bladder. They've come to take part in a reading
study in this laboratory at Rutgers University. Jimmy is flying
through a standardized passage from a first-grade storybook.
The balls used by professionals ...
Wow! Okay ...
Close -- What's that letter? That one after the ďlĒ?
Bla - dder.
STEVE What's that word? Do you know that word?
Great! But Alex is not having such an easy time.
NARRATION Though two years older, Alex can't keep
up with Jimmy in reading. When an otherwise intelligent child
falls two or more years behind in reading level, most specialists
agree on a possible diagnosis: dyslexia.
Now I want you to read some words that are not real words,
okay? Instead, just tell me how they sound. How does this
first word sound?
Good. Now this one.
NARRATION Now we're just going to do some more.
One strategy dyslexic kids often use is guessing at words.
Watch Alex try that in this non-sense test.
See. Scattered. Chad.
Ah, you made that into a real word. one a little closer, okay?
NARRATION Let's look at that.
S - s - scratched.
NARRATION "Scattered" and "scratched" are shrewd
guesses -- Alex is playing off the consonants in the non-sense
word. And he gamely keeps trying.
Stretched? ... Stressed.
NARRATION Exactly what dyslexia really is has been
fiercely debated. Paula Tallal's work here at Rutgers is helping
make this murky label more precise.
TALLEL What they're having trouble with many times is reversals
of letters -- what appears to be reversals of letters, like
"B's" for "D's" or "g's" for "P's". Well, it's really interesting;
it turns out that those are also the same letters that are
the most acoustically confusable along a very important dimension.
And that has to do with how rapidly the acoustics are changing
inside that individual speech sound.
NARRATION When we speak we create sound waves --
and a computer can convert them into pictures. "Puh" looks
like this; "buh," like this. You can see they're the same
except for this short stretch at the beginning -- a few hundred
milliseconds of sound. Paula's theory is that sound changes
this brief are too fast for dyslexic people to pick up on.
So she's testing kids' ability to recognize sound changes.
Okay? Then it's your turn ... Okay, good.
NARRATION Jimmy can remember four tones and press
the corresponding buttons -- even when the beeps are played
quickly. But with just two tones, Alex is uncertain.
Okay, this one's a little tough ... your turn.
Oh no ... Oops!
NARRATION That was supposed to be that one. Trouble
... and to prove that Alex's problem isn't just hearing, Paula
switches to another medium: visual symbols. Alex still can't
do it -- the relationship between this string of symbols and
his button pushing is almost random. Paula's results are clear
and consistent: When information is presented too quickly,
her dyslexic subjects just can't keep up.
The language and learning impaired kids had just as much trouble
visually as they did auditorally. So the problem seems to
be a specific problem that has to do with the rate at which
the nervous system can transmit information that keeps coming
at it, one after the other.
NARRATION At the National Institutes of Health in
Bethesda, Judy Rumsey is investigating the physical side of
this brain processing problem. Charles is about to undergo
a positron scan. It's a painless procedure that allows Judy
to study what goes on inside his brain while he listens and
responds to a quiz.
JUDY RUMSEY Want to just go into the room and just try to
watch the IV, but sit down on the bed. Okay, now go ahead
and sit down and you're gonna lie down and put your head on
this. And let's see if we can get your head positioned.
Okay. I want you to just hold still and close your eyes for
the next couple of minutes. I'll be molding this to your face.
Should not be uncomfortable for you at all. If it is, let
me know right away and I'll adjust it.
This feels a little funny at first but it will be comfortable
after a second or two. Instead of tones or symbols, Judy uses
actual words -- but she's still testing how information is
Okay, we'll begin the scan in just a minute. Now you'll be
hearing pairs of unrelated words and if the two words within
a pair rhyme, you should press the button as soon as you know
that they rhyme. Paul, ready for the injection.
NARRATION As the scan begins, a radioactive tracer
in this solution will make things more visible. Rhyming test
words: Debate / relate, Iodine / serpentine, Improvement /
percolate, Degrade / cascade, Bent / wheat, Vindicate / penetrate,
Hesitate / dissipate, Deviate / permanent, Lace / pace, Salivate
/ cabinet, Lake / break, Sweet / treat, Calibrate / caliber,
Deplete / sustain, Wade / made, Frustrate / translate, Went
/ ray, Defeat / concrete, Negligee / matinee, Dental / angry,
Bent / lament It's not poetry, but it does the job. As Charles
listens to each pair and responds to rhymes, the scanner captures
successive pictures of the blood flow through his brain. Judy
zeroes in on the areas responsible for language processing.
It turns out that some of these brain areas are not active
in dyslexic people.
RUMSEY This is an area in the left parietal lobe important
for language processing. And as you can see here, on the right
in our normal control, there's considerable blood flow and
considerable neuronal activity. On this scan we see the same
slice through the brain of one of our dyslexic subjects. There's
less activity, as indicated by the ... ah ... cooler colors
here and the fact that there's less of the warm colors --
the red and orange in particular -- in this dyslexic brain.
This means that dyslexics are unable to actually activate
this region that normals activate in order to do the rhyme
NARRATION So the evidence is mounting: dyslexia may be an
organic -- even perhaps a genetic -- disability. That's why
the Rutgers lab is now exploring early detection: playing
tone cues to babies, and measuring their response time.
Scene one says the setting is the Imperial Garden of Japan.
Up to second messenger. Early diagnosis will help -- but if
dyslexia really is a physical disability, sustained and supportive
teaching will remain the only way to help these bright kids
become successful readers.
This tree will have to be cut ... cut down. My perfect garden
will be perfect no long ... longer. How... how trouble.
FLOWERS You know, I really identify with Alex, 'cause ! think
I'm at least mildly dyslexia. When I was growing up, everyone
else in my family really enjoyed reading, while I was struggling
with it. The reason that struggle was so frustrating is that
we just didn't understand it.
(V.O.) If I'd been trying to learn something visible - like
how to juggle - everyone would have understood that I could
get one toss at a time, but I just couldn't put it all together.
But if you have a good teacher, and supportive people around
you -- even things that seem impossible - can happen!
FLOWERS In this tropical paradise, animals play.., raise their
young.., and wage the daffy battle of survival. Take argiope
argentata, more commonly known as the garden spider. Every
morning, in the hours just before dawn, she spins a new web.
The raw material emerges from silk glands inside her body.
She is both architect and master builder, as she weaves the
silk into this stunning tapestry. Its sole purpose: to snare
insects for her to eat. At daybreak, Yale biologist Cay Craig
and her graduate student, Cheryl Hayashi, track down the busy
spiders. A mystery spun into the webs has lured them to Panama:
Why do these spiders weave decorations, like this zigzag flourish?
Usually, there's just a single decoration, but occasionally
there are fancier patterns like this. How could decorations
help in the spider's struggle to survive?
Okay, this one's here from yesterday.
That's what Cay and Cheryl are here to investigate. They want
to find out if decorations catch more insects.
Oh, there's no decoration today.
To start they have to inspect an undecorated web. This one
has some holes. Cheryl sketches the damage onto what will
become a sort of baseline map of the web. Now Cay and Cheryl
can spend the next hour finding and mapping new webs, while
everything that goes on back at the original site will be
recorded in the web itself. A lot of bees fly into the sticky
net and then escape, musing only slight damage to the web.
But this bee is not so lucky. The spider wraps her prey with
fleshly made silk so it can't escape. Then she snips the strands
of the web that originally trapped the bee, and carries her
bundle back to the hub - she leaves a tell-tale trail of web
damage in her wake. The meal takes a long one - she has to
break down the bee with regurgitated digestive juices before
she can eat it. While she's busy digesting, a lot of bees
get a second chance. When Cheryl returns an hour later, she
can reconstruct the events of the hour by examining the web
and comparing it to her baseline map.
Looks like about three interceptions occurred. That the spider
actually caught the prey because they're cut out. There's
also a bee that's been caught and wrapped here, and you can
see that the spider went out along this line and came back
in. There are also a lot of other small line damages here
which are probably insects hitting the web and then fleeing
Now they're ready to tackle the mystery of the decorations.
Okay. I think it is from yesterday, right. I think this is
R - 24.
The small spider has spun a small decoration.
It probably has some growing to do.
Will it help her trap bees?
NARRATION During the hour, this spider catches several
bees.., and an unusual delicacy: a large grasshopper, still
alive, struggling to breathe through the thick silk. This
bee has been trying to escape for several minutes. Finally,
it's bound by just a single strand. NARRATION The spider is
not responding. Then the bee gets entangled again. The struggle
Oh my Gosh. What a mess. Look at this.
Big interception here.
The verdict that emerges from hundreds of these maps is unmistakable:
decorated webs catch more insects.
What these studies are showing is that they're really doing
fantastic things, that they're decorating their webs with
brightly-colored will to lure insects to them, to attract
insects to the web.
What is it about these decorations that make them so attractive
- and so fatal - to insects?
Stand by for a minute
Cay has a hunch - and to test it, she's going to take some
Ooh, perfect. Now perfect.
She photographs the web once in normal light, and once with
a special filter that blocks out all light except ultraviolet
light. Ultraviolet, or UV light, is invisible to humans. But
insects not only see UV light;, they see it as extremely bright.
The flowers of many plants, including these grasses, reflect
UV light, so the flowers look even brighter to bees than they
do to us. In fact, LTV light is a kind of beacon for bees,
drawing them to their food sources. So as they fly through
the air, the bees are looking for any surfaces that reflect
UV light. Maybe the silk the spider uses to fashion her decoration
also reflects UV light, just like a flower.
All the visible light has been cut out.
And it's this hunch that led Cay to take these pictures. Here
is a high contrast black and white version of how we see the
web. The decorations stand out, but so do the spider, the
leafy background behind the web, and the entire blade of grass
in the bottom center - both stem and flower are extremely
bright. But in UV light only, the kind of Light that bees
are attracted to, almost everything fades away, EXCEPT the
decoration and the grass flower. This means that they both
reflect UV light. In fact in this light, the zigzag decoration
bears an uncanny resemblance to the flower. Viewed through
a video camera which has been speedily adapted to read only
ultraviolet light, the spider's strategy becomes dear: she
is decorating her web to look like a flower, trying to fool
hungry bees. But one more mystery remains. We know that spiders
are meticulous builders. Day after day, they weave their webs,
never varying the basic structure. But the decorations change
all the time. Sometimes a single arm pointed this way, sometimes
that way. Sometimes 2 arms, or even 4. Even more baffling,
on some days the spiders don't decorate at all. That makes
no sense, since decorated webs attract far more insects than
undecorated ones. Is this just random behavior? Or are the
spiders up to something? To fred out, Cay has devised an experiment
to ask the bees. Assisted by Jennifer Maas, Cay lures the
bees to the site of the experiment with a dish of sugar water.
Once the experiment begins, Cay needs to track the behavior
of each individual bee. That's a Problem. They all look kind
of similar. Solution: nail polish. Fortunately, these bees
Gold top, dark blue bottom. We haven't had one of those yet.
Each bee gets its own individual marking, so it can be recognized
later. Then Jennifer heads into the wild, to find the decorations
they need for the experiment. She carefully lays the decoration
onto a piece of sticky acetate. A web strung across this hoop
goes directly in front of the sugar water dish.
Are you ready, Jennifer?
Then it's decorated. The bees still want to get to the sugar
water. But now there's a decorated web in their way. How will
Gold top, pink bottom.
Cay looks for the individual bees that she's marked. Here's
the gold one.
Jennifer keeps track of what the marked bees do. Most of them
are getting caught. But since there's no spider to finish
them off, they always eventually escape. Do the bees learn
something from this experience?
We think that flying into a web is pretty traumatic. It's
kind of like if you slam your hand in a car door you're not
likely to do it again, because it's just a really strong signal
that will help you remember in the future.
Yeah, avoid, around, you're right.
After getting caught a few times, the bees do learn to avoid
the web and fly around it. Here's a slow motion replay. The
gold bee, who's gotten caught several times in the past, now
flies around the web. So the bees have learned to avoid a
web that's decorated like this. But what happens when Cay
changes the decoration by pointing it in a new direction,
Blue top, pink bottom. Caught.
NARRATION Cay will have to repeat this experiment many times,
to make sure, but it looks like the bees are now flying right
into the web, as if they'd learned nothing at all.
Caught, caught. Maybe changing the decoration confused them.
Well the idea is that if the bees see the same decoration
day after day, they may be able to learn to avoid the web
more easily, then if the decorations constantly changing.
So that could explain why the spiders have evolved to spin
variable decorations, why every individual spins a different
decoration, and its unpredictable.
The spider and the bee are locked in a life and death struggle.
The spider comes up with a trick to trap the bee; the bee
either catches on or ends up as spider food. And when enough
bees catch on, it's time for a new trick, or the spider goes
hungry. This is the battle of the hunter and the hunted -
played out by individuals, but evolving over thousands of
generations. New moves keep the hunters ahead, new countermoves
keep the hunted alive.
FLOWERS That's it for this edition of Scientific American
Frontiers. Be sure to join us next time, for a rare and exciting
look at science in the Middle East. From the Pyramids near
Cairo to the Bible lands around Jerusalem - from the rediscovery
of ancient music to the latest research on newborn babies
-- you won't want to miss Frontiers in Egypt and Israel. So
please, come on back and watch.