ENDANGERED WONDER DRUG
RESTROTING THE PRAIRIE
INVASION OF THE PUPAE SNATCHERS
NARRATION A chemical in this tree may cure cancer
- but there's not enough for every patient. Search for new
sources on Scientific American Frontiers. Also: Hot wheels
designed by users take the lead in the Boston Marathon. Ants
battle for life and death on the forest floor. In the air
-- a contest of flying robots. And setting fires is the secret
to saving the prairie. All next, on Scientific American Frontiers.
FLOWERS Hi, I'm
FLOWERS and welcome to Scientific American Frontiers. You
know, a modern pharmacy like this is full of miracle drugs.
Here's a whole row of stuff for people with colds and allergies.
And this one is used to treat some forms of high blood pressure
.... modern miracles? Well, it turns out that people in India
were making this one out of snake root at least 300 years
ago and healing with the afredra plant which is the raw material
for these decongestants began with the Babylonians more than
5,000 years ago. Now, it may come as a surprise, but in out
own hi-tech era, nature is still the most important source
of new medications and you just couldn't ask for a more dramatic
example than our first story.
The Cascade Mountains of Oregon -- home to some of America's
very own rain forest. Phil Hassrick and Jerry Kordan are out
to find a very special inhabitant of these old growth woods.
This is their quarry - the Pacific yew. It grows only 30 feet
high, and has no commercial value compared to the big stands
of cedar and fir. So why are they cutting it down? 3000 miles
away, Elaine Hess is entering the Johns Hopkins Hospital.
Elaine has ovarian cancer. She needs what's inside that yew
tree -- an experimental drug called taxol. It's her best hope
for stopping the deadly disease.
HESS I am young and stronger and better able to fight. I know
the statistics for ovarian cancer aren't that great but I've
never been a person to go with statistics that much myself
anyway. I'm going to fight as hard as I can and just go day
by day. And I feel that with the taxol I have a much better
Elaine may have reason to be optimistic. She's part of a clinical
trial that's being run by Dr. William McGuire. The Johns Hopkins
trial has produced encouraging results.
WILLIAM MCGUIRE Some 30 to 40% of ovarian cancer patients
who don't respond, or have stopped responding to other drugs,
respond to this drug. Often times their responses are dramatic
responses. The tumors went away.
Elaine's tumor is shrinking -- she and her husband may soon
be on their way home.
WILLIAM MCGUIRE .... this afternoon. Hopefully, we'll have
you out of here by Wednesday morning and then you'll see me
in 3 weeks. At that point we'll repeat the cat-scan and hope
to see that the disease is small or possibly even gone.
ELAINE HESS Okay, that sounds good.
Taxol was discovered by the National Cancer Institute in a
random sampling of plants in the forest. Yew tree bark is
rich in taxol, so Phil Hassrick is collecting it for the clinical
trials. Peeling off the bark kills the tree, but right now
this is the only way to provide the drug to cancer patients.
And this is the distilled essence of that yew bark: 200 milligrams
of the refined drug taxol, today's prescribed dose for Elaine
Okay Elaine, you have your taxol. We're ready to start. You
How does your arm feel?
The taxol is given intravenously -- six doses like this one
over a four-month period.
Your heart rate is pretty much baseline, but remember when
we start I want you to let me know if there's any pain in
that site. If you have any chest discomfort at all or any
So far, Elaine is one of the lucky ones. She's not cured yet,
but for her and the 20,000 American women diagnosed each year
with ovarian cancer, taxol is the one promising medicine on
the horizon. But behind this exciting potential looms a serious
problem. If taxol succeeds here, there may not be enough of
it to treat more women like Elaine. The problem lies in the
old growth forests scattered throughout the Pacific Northwest.
For the past 80 years these virgin stands have been cut for
their timber. The efficient modern method is clear cutting.
These areas will be replanted, but only with one or two commercially
valuable species. The rich diversity of plant life that was
here, including the yew, is gone.
HASSRICK Prior to the finding of taxol the yew tree was considered
a nuisance species to the point where no one had any idea
how many trees were in the forest. They were regarded as a
menace, they would cut them down or they would try and lay
the big trees down on top of them and use them for a cushion
so that the big trees didn't get broken as they fell.
In just two years, all that has changed completely. The Pacific
yew is now a very valuable tree. So Phil Hassrick's company,
Hauser Northwest, hustles into the forests before they are
clear-cut to remove the bark. But even this is no real solution.
As the yew is removed, no one is replacing what is taken.
The wild supply of the drug is being diminished. Even if all
the yew trees are harvested, there will not be enough taxol
to meet future demand. That's because it takes a lot of bark
to make a little taxol. At Hauser Northwest's collection center,
thousands of yew trees are stripped and reduced to handfuls
of bark chips. It takes about 30 trees to fill this box with
chips -- and that's only enough to treat ten women with ovarian
cancer. If taxol also proves to be effective against lung
and breast cancer, 10 times more bark will be needed.
HASSRICK If this drug is a success, we're going to have a
problem. The demand for the drug and the demand on harvesting
it from the forest will increase as much as possible. I don't
think there's a limit to how much that they can take. And
for that reason I think that we have to find alternatives
as soon as possible so that we can be out of here and that
we can not damage the speeds irreparably.
One alternative is to grow the yew. Here in Corvallis, Oregon,
a U.S. Forest Service project is planting cuttings from wild
trees under controlled conditions. Researcher Nan Vance's
goal is to find out how to cultivate the trees for maximum
taxol production. But growing these cuttings into mature trees
will take 80 years. That's when the bark will be ready for
harvest. One new idea is to tap the young needles instead.
Taxol is present in these needles, but at much lower levels
than in the bark. New work suggests that this approach could
lead to a renewable source of the drug, if researchers can
grow high-yielding yew needles. But getting to that point
takes lots of basic research. To gather information Nan Vance
is stalking wild samples of yew to find genetically superior
taxol producers. She's also looking for how growing conditions
influence taxol concentration. For example, she takes samples
from this shady understory where the trees get very little
light. Then Nan and her colleague Rick Kelsy visit another
area, where yews are growing in sunnier conditions. Comparing
the effects of different light levels takes painstaking analysis
in the laboratory. The samples are evaluated and plotted,
to pinpoint the most important influences on taxol production.
KELSY Okay, there's our sun sample. Now we've got an overlay.
This is your shade taxol and this is the sun sample, its taxol.
VANCE No ambiguity about it. That's very good.
If these preliminary results hold up, and shade stimulates
higher taxol yields, then Nan will have to mimic the natural
shady condition of an old growth forest to raise the most
productive yew trees. Meanwhile...far from the forest, a dramatically
different approach to the supply problem: making taxol without
the yew tree. Bob Holton, a chemist at Florida State University,
is using a computer to model the problem of building a synthetic
taxol molecule. It's quite a problem --taxol is one of the
hardest natural chemicals to copy.
HOLTON This is a model of taxol which shows its complexity
and its shape. There are essentially two parts, one is this
part which looks much more complicated and the second is this
part down here which has been know as the taxol side-chain.
The simpler side chain is what Bob Holton's team tackled first.
After years of effort, running thousands of chemical reactions,
they succeeded in synthesizing an exact replica of the chain.
But the more complex main ring remains out of reach. So Holton
has gone back to nature to get some help.
HOLTON There's another naturally occurring molecule known
as baccotin III which is identical to taxol except that it
has no side-chain. It is obtained from the leaves of the English
yew and perhaps many other varieties of yew, and is a much
more readily available material than taxol itself. So what
we have done is gone ahead and develop a procedure to attach
the side-chain here to baccotin III to make taxol.
Thanks to Bob Holton's insight, a whole new source can now
be tapped to make taxol. And it lies as close as our own backyards.
The English yew and other ornamental varieties have Baccotin
III in their needle. Each spring at nurseries around the country,
these young yew bushes are pruned. The clippings are left
to rot. Here at the Zelenka Nurseries in western Michigan,
the world's largest grower of ornamental yew, this spring's
pruning is being done differently. For the first time, they're
using combines to prune the yew bushes, so they can collect
the potentially valuable clippings. It's the world's first
ornamental yew harvest. The objective is to produce baccotin
III and taxol for testing by the National Cancer Institute.
We still don't know if making synthetic taxol on a large scale
is viable, or if this hybrid chemical is as effective a cancer
treatment as the natural variety. If it is, then these needles
... combined with the chemical side chain from the test-tube..,
may one day produce this needed drug in commercial quantities.
But remember, these alternatives are still only fledgling
developments. For now, the old growth forest is the only place
to go for taxol -- and for other discoveries that may be just
HASSRICK More than 70% of the drugs that are available on
the market come from natural sources and are extracted from
natural products. We don't know at this time what's in this
forest. We have no idea how many more taxols there are out
there to be found, and what sorts of diseases and what sorts
of benefits they can render to man.
FLOWERS In the time it took to watch that story, more than
a thousand acres of the world's tropical rainforest were destroyed.
That's more than 50 million acres a year which is why so many
people worry that some day greenhouses like this may be the
only place to find many tropical plants and trees. One reason
environmental groups argue we have to save the rainforest
is that we may be throwing away valuable medicines ... maybe
even a cure for cancer. Now, along comes taxol, a real example
of a treatment for cancer that comes from rainforests right
here in the United States. When you consider that half the
plants in the world live in tropical rainforests and that
only one in a hundred have been screened for their medicinal
value you wind up with one solid practical reason for worrying
about the fate of the forest. Those trees that seem so far
away may one day save your life.
The starting gun of the Boston Marathon - one of the world's
premier sporting events. Just to make this field, you need
legs of steel. But some competitors can't use their legs at
all. Paralyzed by injury or disease, these racers will pull
themselves through 26 miles in wheelchairs. Like every runner
here, they have to be in top physical form. But to win in
this division, they also need hot wheels. Fast chairs are
part of a design revolution -- a profound change that's been
engineered by wheelchair users themselves. One of these user-designers
is Rainer Kueschall. He didn't set out to be an engineer -
but life left him no alternative.
KUESCHALL When you are very limited you only have 2 choice
to go forward or stay where you are and suddenly one day comes
and you say 'I have to do something with my life'. Which way
shall I go? And I went a positive thinking way.
Watching Rainer work out in his native Switzerland today,
it's hard to believe that a diving accident 26 years ago left
him virtually paralyzed. His long recovery was made even more
difficult by the wheelchair he was given. It's tough to push
that conventional wheelchair, even up a ramp, as Rainer's
associate demonstrates. As for climbing over curbs -forget
it - at fifty pounds, the chair's too heavy. And the main
wheels are so far back that steering and maneuvering are really
tricky. For Frontiers, Rainer reluctantly agreed to get back
into the old standard wheelchair. All the discomfort and dissatisfaction
he experienced years ago came back as forcefully as ever.
KUESCHALL My seat position is not good enough. My legs are
much forward. The mobility is absolutely eliminated so I feel
Rainer refused to endure these limitations. Ten years ago,
he decided there was only one thing to do … design his own
KUESCHALL (V.O.)/SYNC I feel free.., maneuverable.., only
like that am I able to be active. I think as you saw me before
I never have a chance to survive outside.
The standard wheelchair is heavy and high off the ground.
Rainer's chair is lighter, lower to the ground, and most important
- the back wheels are directly beneath the seat. That makes
it easier to maneuver the chair and to get more power into
each push. Today Rainer is a world leader in wheelchair design,
and he operates a factory in Basel. The engineering changes
he made are simple enough - but they make a big difference
because they come from a personal understanding of wheelchair
KUESCHALL We are wheelchair users and it is in our interest
to squeeze the maximum out of it. That's why I think we found
all these technical improvements in a short period of time
that nobody saw before.
Thanks to Rainer, and a handful of other user-designers, wheelchair
riders can now tackle just about any sport they choose. One
athlete who's made the most of the new mobility is Bob Hall.
Like Rainer, Bob rejected the limitations of the standard
HALL I found that the wheelchair was the most disabling aspect
of my being and that really held me back. It was made for
not really any other purpose than to sit there and I wanted
to move and move fast.
In 1975 Bob became the first athlete to complete the Boston
Marathon in a wheelchair. That first ride was in this conventional
chair. But he too became a user-designer - and built this
racing chair. The back wheels are angled -- that puts the
tops within reach for a power push, while providing maximum
stability at the bottom. Bob's latest is this three-wheeler.
A mere 17 pounds, it's been clocked at 40 miles per hour.
Three weeks before the Marathon, Bob is struggling to come
up with the extra edge of speed that could make him the winner.
To give the chair sleeker lines, he's considering an idea
from auto raring: taper the squared off back, so the whole
flame becomes a streamlined diamond. And to reduce the weight,
Bob's got another trick. For the first time ever, he's fashioning
a wheelchair frame from titanium. It's an idea he got from
raring bikes, which use titanium because it's light but extremely
strong. With some delicate finishing work, the diamond frame
is completed. And to get the most out of the new design, Bob's
bringing in a top young racer. He's Craig Blancherte - featured
in this Nike commercial. Craig is a genuine sports star who's
making it big. Three days before the Marathon, Craig flies
in from Oregon to take on Bob's new machine.
BLANCHETTE How light is it?
HALL What do you think?
BLANCHETTE It's awesome. It's awesome.
HALL I think it's about 12 1/2 pounds.
BLANCHETTE Really...pretty amazing.
Craig's usual event is sprinting - and he discovers he can
really fly in this chair. Now he wants to check out a key
racing strategy - drafting. With the old three-wheeler up
front, Craig gets close in - then he can ride the draft of
reduced air resistance, and work less hard. Bob's design is
shaping up as a real contender. Back in Switzerland, Rainer
is also making final preparations for the coming race. As
a quadriplegic, he won't compete directly with Craig, or with
paraplegics who have full upper body strength. But just being
in the same race is a personal victory.
KUESCHALL I think it's natural when you are slow you want
to be fast. And when you see the big boys, the paraplegics,
and so on you saw the possibility they could move and so ...
I think it always a little dream of a quad, 'Wow, if I could
just do that',
Race day in Boston ... the preparations are over ... time
to warm up ... for runners ... and for wheelchair racers.
Craig's new chair is ready to roll. Now the pressure's squarely
on him: Can a sprint racer really cut it over the marathon
BLANCHETTE I'm feeling anxious and nervous actually. I'm ....I
really don't know what I'm feeling actually.
Fifteen minutes before the foot racers, the wheelchair racers
take off on a rolling start. That's Craig in the blue helmet.
The official whistle, and they're off. After just a few minutes,
the field thins out, with Craig up front. Two miles later
... this trio makes a break from the pack ... with Craig hanging
onto third. Jim Knaub, the 1982 and '83 winner, pulls ahead.
Craig - already a little winded - remains behind to ride the
draft. Then, with a sprinter's spurt, Craig makes his bid
for first place. Soon it's just a two-man race, with Jim and
Craig trading first place. But behind the leaders ...the infamous
Heartbreak Hill takes its toll. And for Rainer it's especially
grueling. He's completely exhausted - he can't push anymore
- but the crowd keeps cheering him on, and he pulls himself
up the hill. Meanwhile, at the front, Jim Knaub begins to
pull away from Craig. In a distance event, you've got to know
how to pace yourself... Craig's fast chair can't make up for
his inexperience. And the veteran wins his third race. hour,
thirty minutes. He's wheeled 26 miles in one. Four minutes
later, Craig comes in second ... an outstanding finish for
his first shot at a major marathon.
BLANCHETTE Basically, all I did was try to hold onto second.
I tried to dial 911.
Rainer finishes in a respectable three hours - his bravery
and persistence paid off.
KUESCHALL It's the hardest race I ever did. These hills take
everything out of you. It was unbelievable ... the crowds.
These people are absolutely crazy so I never could allow me
to give up.
The new mobility has progressed so far that a hundred-year-old
foot race now has two winners. And as user-designed technology
becomes available to all disabled people, everybody wins.
FLOWERS Scientists today are in danger. Danger of being buried
under all the numbers pouring our computers, but there's hope.
We're learning to use these computers in a new way to create
pictures to help make sense out of numbers. And sometimes
pictures produced in this process of scientific visualization
turn out to be real works of art. As a regular feature of
Frontiers we're going to look at some extraordinary images.
They may come from microscopes, sensors, TV cameras, or computer
animation. What they have in common is enabling us to see
something marvelous that we couldn't see any other way. This
time we travel inside a severe thunderstorm. Courtesy of the
National Center for Computing Applications at the University
of Illinois we get kind of an x-ray view of how a storm builds
PACKARD I'm standing on what was the prairie, the tall grass
prairie, now one of the rarest ecosystems in the world. This
is why it's so rare. This place, the buffalo pawed here. The
rain fell on the prairie flowers and prairie grasses. It says,
"Prairie View Plaza" over there. I don't see it. What I would
like to see, if I saw the prairie, I would see a mass of blue
flowers here, then a mass of green over there, tall grasses
waving back and forth, the buffalo comes wandering through
over there, big masses of them.
Steve wants to see more of this - original prairie. Once it
covered 150 million acres, but after European settlers arrived
in America, almost all was turned into farms and cities. We
need farms and cities, Steve's the first to agree, but now
the prairie's nearly a dead ecosystem. Just a few isolated
patches like this remain, hemmed in by trees. It's time to
do something about it. And a lot of people agree. Today, they
meet on public land near Chicago.
PACKARD What our goal here is, on this little piece, this
little six hundred acres, is to put it back the way it was
when the buffalo walked across this ground, 200 years ago,
2000 years ago, 8000 years ago.
They won't be tearing down farms and cities, but they will
attack something else that replaced the prairie - forests.
Every tree in sight comes from Europe or Asia, brought in
by settlers. Foreign trees have choked out much of the original
prairie, stealing sunlight and water. So before prairie seeds
can be re-sown, the land must be cleared of everything but
the few natives - giant burr oaks. Hundreds of years ago these
trees stood alone, amid the grasses.
PACKARD And we will take these wonderful little rakes that
sound like Hare Krishna bells, don't they? You know it helps
the seed, we go "Ah, yeah..." really helps them. We'll do
some strips, through there.
Steve scatters rare prairie seeds on an already cleared area.
Foreign grasses are established here. But the rakes drill
the seeds into the soil, where the chance to sprout and compete
is best. The prairie grasses won't win back this turf for
decades. But to those that labor, it's worth the time and
SYNC The work out here is what makes me feel my life is counting.
This is the important part. I feel like I'm not only doing
a nine to five job in an office, that I do all the time, but
I'm doing things that make me feel like I'm helping the Earth
a little bit more.
MAN SYNC My ancestors came over in about the 1870's from Ireland,
so I can imagine what they saw, none of my family has seen
for possibly about 50, 60, 70 years. So I'm going to relive
somewhat what they saw previous.
PACKARD People think of frogs as creatures of ponds, but this
guy lives in the prairie ... a leopard frog. Making a little
All sorts of prairie creatures are now showing up in a patch
of land they've been working on for the past 7 years.
PACKARD This is a katydid, and they only grow in the prairie
and while we're saving 50 species of plants, we may save 500
species of guys like this.
And even fire has a place in bringing the land back to life.
Winter's over, and underneath the carpet of dead grass, there's
a prairie waiting to get out.
PACKARD These are the weed grasses. These are the ones that
we don't want. This one, I see the little cup shaped end,
this is Kentucky Bluegrass. And the fire's going to kill it.
Unlike the imported bluegrass, native prairie plants do well
in fire. The inner kernels of their seeds can survive intense
heat. And not only are they safe from fire, they depend on
it. The flames will help burn off the thick outer coats of
the seeds, so plants can sprout. Started by lightning, fires
were once a frequent, natural event here. But as the prairie
was broken up by farms and cities, fire could no longer spread
and do its job. Now it's up to people.
PACKARD This is probably as much white prairie clover as there
has ever been in one place, and I'm, .. it's just awesome
to me, and .... This is a very rare plant.
Again, people must lend nature a hand.
PACKARD What you'll be doing is simulating a cow's stomach,
a buffalo's stomach, rather!
The buffalo and its stomach juices are gone. They, like fire,
used to help eat away at the tough outer seed coat of prairie
plants. Now, sandpaper does the job. The best time to plant
is when the ground is still warm from the fire. To restore
the prairie is a long-term battle -- Every year the seeds
of foreign species will blow in and try to take root. But
so far ... the prairie shows signs of winning.
PACKARD This is wild quinine, wonderful little rare prairie
species. This is early goldenrod. Not the weedy goldenrod
you might find down the street, but a nice prairie one. This
Indian Grass is in bloom -- all the little yellow stamens
hanging out. This is a patch here. There's a patch over there.
There's a patch over the other side of this hill. It's going
to make seeds like crazy. They're going to blow all over the
place. Pretty soon, the prairie is on the way back.
At the University of Texas in Arlington, an aircraft with
a strange mission is revving up. Today pilot Steve Spence
plans to fly the vehicle using a radio controlled joy stick.
But it's just a test -- because eventually this vehicle will
have to lift off and hover on its own -- as a flying robot.
It will compete with robots from other schools, in the first
ever aerial robotics contest. To qualify, computers not man,
will have to control the machine. For the contest, a sand
volleyball court will be covered by a rubber mat and the net
replaced by a 3 foot tall barrier. On one end will be a source
ring, containing 6 neon orange disks. The object -- a flying
robot must pick up one disk at a time and bring it over to
a target ring on the other side of the barrier. The contest
is the brainchild of Georgia Tech Professor Rob Michelson.
MICHELSON One of the tasks that has to be performed is to
locate these disks. The vehicles will have to fly over the
ring in which these disks are contained and then look down
or feel around to find the disks.
Back in Texas, they're testing a small search camera, attached
to the bottom of the robot.
CILIA OK David, bring it in.
The camera sends its picture to a computer.
OK, slowly now. OK, track one. When the faint white lines
cross, the computer has recognized a disk. Now the robot has
to pick it up.
MICHELSON These disks have been designed so that they can
be picked up with a suction device, some sort of tactile grabbing
device, or, they can be picked up magnetically.
A pulley draws the magnet and disk up to the base of the vehicle
-- where they sit until the robot navigates its way to the
MICHELSON Navigating may be one of the easier tasks that has
to be done, because the teams are allowed to set up navigation
devices around the arena.
Texas is sending sonar signals to a receiver that will eventually
go on the robot. Signals are sent out by six sonar beacons.
As the vehicle moves, the distance each signal travels will
change. An on-board computer calculates position, based on
the changing distances, and tells the robot where to go next.
SMITH (VOICE UNDER) OK stop, now do the rotate.
Sonar is nothing new -- the hard part is programming the robot's
onboard computer. It has to interpret the navigation data
.... and control everything else the robot does. And because
it's a contest, the work goes on in secret.
SMITH Some of the schools are probably doing things that are
totally different than what we're thinking about, and it gets
your adrenaline going. In San Luis Obispo, Cal Poly is building
SUFFREDINI OK, well as you can see here, we're running on
a Briggs and Stratton 3 amp/horsepower motor. It's just turning
this plastic fan blade, much like a standard lawn mower would
It even starts like a lawn mower. It qualifies as a flying
machine because it's not touching the ground. Two more fans
give the hovercraft a surprising amount of thrust. The hovercraft
is speedy and stable -- but it can't fly over a ring. The
team plans to throw in a claw to pluck out the disks. The
claw is part of a five foot tall arm they're attaching to
the top of the robot. The disks won't have to be located by
a complicated camera system. The arm will just feel them.
As it sweeps around the ring, it catches all the disks. But
that's a problem.
MICHELSON The rules state clearly that you can only carry
one of these disks at a time.
So, a flap will close when the first disk gets caught. Since
the other disks won't be locked in place, they should fall
out when the arm lifts up. But it's not easy to teach the
MICHELSON I didn't want to design something that everybody
would finish with an A+. I wanted it to be a challenge. Therefore
it's a very difficult contest, I don't believe it's impossible.
I don't know that everybody will be able to move all six disks,
in fact I doubt that any of the teams will move all six disks.
And now, the day of reckoning.
MICHELSON Ladies and Gentlemen, welcome to the First International
Aerial Robotics competition…
Four teams have entered. The judge briefs the first team up,
the University of Dayton from Ohio. JUDGE ...and you tell
me when you're ready and that's when we'll start the clock...
They entered late, and haven't had time for a test flight.
Their passenger sits in on the maiden voyage. The vehicle
is a helicopter ... run on gasoline.., and controlled by computer...
or not controlled, as it turns out. At least the passenger
We're still intact!
BAKER Mechanical problems will happen. The world's not perfect,
and we didn't have it balanced out quite well enough, and
the computer couldn't control it.
Next, the hometown team, Georgia Tech, has a sad announcement.
INGALLS We've been working almost night and day for the last
three or four months, and as of 4:30 this morning we had an
engine failure that we just couldn't recover from. So we're
sorry to say that we won't be able to show you anything, at
least in the arena. But feel free please to come back and
ask us questions about our aircraft, cause we're terribly
proud of it.
The unwieldy hovercraft is brought in by Cal Poly team members.
The judge looks on as the craft makes its way right to the
ring ....and keeps going. The navigation system is out of
order, so the team's out of the contest. But to demonstrate
what it can do...they push the craft back. Some changes are
made - with laptop computer in hand - and the claw descends
into the ring by itself. It sweeps over the bottom - feeling
all six disks. And only one disk is lifted out. The robot's
arm works perfectly.
PETERS You know, we did pretty well. The control system works,
and, uh, the arm works, and there's just a little bit more
fiddling with it and we'll probably have a working system.
Next up, Texas.
SPENCE When you have to let your baby go, you know, it's like
parents kicking their kids out of the house, you know. It's
gone, you know, it's all on its own now, you know.
Sonar beacons - on the fence. The receiver -- on board. Now,
it's all up to the computer. Steve carries the remote control
joy stick box out of the arena. He's only allowed to use it
as a safety - to stop the robot if it accidentally flies outside
the contest area. In its rather short flight, the Texas robot
actually accomplished a lot.
SMITH It went directly toward the ring, didn't it? And it
got off the ground, which is a great accomplishment.
As soon as the robot took off, it headed directly to the ring.
The navigation computer calculated the correct position. But,
as the aircraft moved in to hover and search for the disks,
the landing gear, enlarged at the last minute, hit the edge
of the ring. The computer couldn't correct the balance in
time. Still, at an almost impossible task, it was an impressive
I think it's evident, that University of Texas at Austin,
uh, Arlington, was the defined winner.
The Texas team has taken a first small step in aerial robotics.
There's high hope for the future. But as for the present,
one team insists they hold the best current technology for
SMITH I guess they just can't take the man out of the machine!
OF THE PUPAE SNATCHERS
It's a sunny Tuesday afternoon in the Chiricahua Mountains
of Arizona. And there's a strange group of people who are
looking for something.
TOPOFF We’ve got a colony-with the queen and brood! And, but
she got away. But she certainly was onto the rock.
Yes, believe it or not, this is a hunting trip for ants. Howard
Topoff and his students at the Southwest Research Center know
exactly where to find them--which is about everywhere. But
they are after just one particular kind.
TOPOFF The vast majority of ants can take care of themselves.
But a small group have lost all those abilities. They become
parasites. They can't get any food for themselves, they can't
clean their nests, they can't feed their young, they can't
feed their queen. The only adaptation they seem to have left
is the unique ability to get other ants to do all these jobs
And these are the crafty parasite ants. They are called Polyergus,
red in color, about a quarter inch long--and ruthless. The
Polyergus parasites are good at just one thing: making war.
Howard, they're raiding.
TOPOFF There they go. Up here.
Practically every afternoon, not just Tuesdays, the parasite
ants send out their armies. As the marauding hordes stream
over any obstacle, other ants in the forest are cowering in
their nests. Who is going to get hit today? The parasites
have found their target. The first innocent victim is slaughtered.
And it's always these peaceful Formica ants that are attacked.
Now the raid is in full swing. Quick as a flash the parasite
ants climb down into the nests and haul out the living white
pupae of unborn Formica ants. The red parasite rush their
booty back across the obstacles into their own nests. And
inside is the most amazing sight. It's full--not of red ants,
but of their victims, peacefully looking after red-ant pupae,
as well as their own. Today's raid has brought more victim
pupae, ants that will be born into slavery. In his lab Howard
studies this strange relationship. The victims are well armed.
They give off poisonous formic acid. So do the red Polyergus
parasites. But look at what happens when the two types meet.
In this test they will be kept apart with a wire mesh, but
they can still use their chemicals on each other. The result
is always the same: even though they both have the same weapons,
it's clear that the Formica victims are not doing well out
of the exchange.
TOPOFF After just a few minutes, all the Formica workers are
dead and all the Polyergus workers are still running around.
This suggests to us that the Formica workers are indeed sensitive
to this noxious chemical formic acid. The couldn't care less.
They seem to be virtually immune to it.
The parasites are unbeatable. And they're superbly organized
DR. HOWARD TOPOFF This scout has just begun scouting. It's
kept a relatively straight line from the nest, moving in a
southwest direction. It hasn't even started to lock for nests
Every day parasite scouts move out in different directions
to look for victims. Now this one is about a hundred feet
TOPOFF She starts circling around, making loopity loops, running
in a kind of a tortuous path. Now she's actually looking for
Formica nests. And as she moves she sticks her head, sort
of pokes her head underneath rocks and leaf litter, and underneath
There's a quick fight when a nest is located. The inevitable
outcome. And then back runs the scout to call out the troops
for a raid. But not so fast. bigger than you. If you're an
ant, there's always something There'll be no raid today. It
occurred to Howard that it was not just spiders that could
stop the raiding. He's mixing up some honey water. And he'll
place it where some Formica victims will find it.
TOPOFF I'm putting the honey water down on the ground where
there's a trunk trail of Formica workers. They are going back
and forth, looking for food. And it will take but a minute
for them to find the honey water and they'll probably start
to recruit nest mates within a couple of seconds.
Remember: these are victim ants. They work for the parasites,
and feeding their masters is one of their tasks. Very quickly
they clean out the dish of honey water and then they will
head back to the parasite ants' nests, their adopted home.
Inside the nest they regurgitate the honey water and feed
their masters. Table manners aren't a big thing in the ant
world. There was one striking result of Howard's feeding program.
DR.HOWARD TOPOFF We find that if we keep feeding the Formica
workers over a period of several days, slowly but surely the
number of raids starts to decrease in frequency. And it remains
low throughout the entire summer. So what we have learned
from this experiment is that the Polyergus raids are at least
in part motivated by hunger.
So when the parasites steal pupae, they get new workers--and
food. But for parasite ants, perhaps the biggest challenge
is starting a new nest.
TOPOFF In most of this species of ants, the queen, after mating,
digs a little hole, lays a few eggs, and when those eggs hatch
into larvae, she feeds them. But a Polyergus queen is kind
of in a unique situation because she is, after all, a parasite.
She can't take care of her own eggs. She can't even take care
This is a Polyergus parasite queen. She is being released
near a Formica colony, so far undisturbed by any parasites.
The Polyergus queen is peacefully laying eggs surrounded by
her attendants. Almost immediately, Formica guards rush to
attack the parasite queen--but it's no use. Then the parasite
queen pulls an astonishing trick. She plays dead, and allows
herself to be dragged into the nest, as if she were a piece
of food. By now the threatened o~ queen has retired to the
corner, but her attendants don't seem to realize the mortal
danger. Suddenly the Polyergus parasite queen reveals her
true identity. There's panic in the nest. She rushes to attack
her target--the hapless Formica victim queen.
TOPOFF The fight between the Polyergus queen and the Formica
queen is very, very prolonged, very, very brutal, and very,
very intense. We think that the Polyergus queen, by continuously
biting the Formica queen, is perhaps getting some of the chemicals
that identify the Formica queen as a queen. She covers herself
with them. That may be why the workers of the Polyergus queen
eventually treat the Polyergus queen as their own.
The battle royal took over fifteen minutes--but the Formica
queen was doomed from the start. She's dragged away by her
own offspring, who have become a peaceful new nest of victims,
ruled over by the parasite queen.
FLOWERS They are tropical carpenter ants, like the kind that
will chew up your house if you are not careful. Now listen.
Know what they're doing? They are actually banging their tails
on the floor. And like the killer whales in our first story,
they are communicating. That's what Norm Carling at this lab
here at Harvard has figured out. He thinks they are saying,
"Trouble. The nest has been disturbed." He thinks that because
right after the alarm is sounded, every single ant starts
putting the nest back together. Ants don't just use sound
for communication. It's more common as the ants and other
insects use chemical messages. Like the parasite queen in
our story. She fooled her new victims with a chemical lie
that announced that they should now serve her. Actually, that's
a good example of the kind of odor trickery that's beginning
to serve a very useful purpose. It can provide new ways to
control pests without using large doses of environmentally-sensitive
pesticides. That's it for this edition of Scientific American
Frontiers. Next time we'll hold a kayak race off Alaska, track
down some wily spiders in Panama, and find out why babies
babble -- everywhere. So please, come on back and watch.