Spin, Spin, Spin
Song and Dance
ALAN ALDA There are spiders… and then there are spiders.
ALAN ALDA (Narration) Rosie the tarantula isn't even the biggest…
or the ugliest. Dancing spiders… aggressive spiders…even cyberspiders.
Spiders in their webs…
ALAN ALDA What happened?
ALAN ALDA (Narration) Spiders in the jungle. Virtual spiders… to
ALAN ALDA Oy! This is the first time I've been able to scare a
spider. I'm Alan Alda. Join me as Scientific American Frontiers
explores the slightly sinister world of spiders.
ALAN ALDA When I was a kid in California, I once found a tarantula
in the shallow end of the family swimming pool, and I panicked.
I didn't know what to do. I started frantically and clumsily
to kill it. It was a disturbing experience, and ever since,
spiders have made me kind of uneasy. You know, all those angular,
sometimes hairy legs; the way they scuttle out of the shadows,
clearly heading straight up your pants' leg; the feel of a
web suddenly draping itself across your face. So an hour program
devoted to spiders? Are they kidding? Well, once I got to
know them, it turned out that spiders are among the world's
most amazingly inventive creatures. And now, I not only find
them interesting, but with the help of a fellow arachnophobe,
I finally made my peace with a tarantula.
ALAN ALDA (Narration) A web glistens in the early morning sun in
a field in Denmark. My companion, from the nearby University
of Aarhus, is Fritz Vollrath.
ALAN ALDA Have you seen anything here?
ALAN ALDA (Narration) Fritz wants to know how orb-web spiders plan
and build such exquisite structures.
ALAN ALDA I see, oh yeah, it's very big
VOLLRATH Wonderful. It's gigantic.
ALAN ALDA Is that the spider up there?
VOLLRATH Yeah, that's the spider. Shall we get her out?
ALAN ALDA (Narration) The web was built by a very pregnant female
lurking at its corner.
FRITZ VOLLRATH There she goes. A bit of water…
ALAN ALDA (Narration) Fritz sprays the web with water to make it
VOLLRATH Ah ha, she's interested in the fly, and the water…
ALAN ALDA (Narration) But -- perhaps because she's pregnant
and feels vulnerable out on her web -- she beats a hasty retreat.
ALAN ALDA Are we disturbing her at all?
FRITZ VOLLRATH Yes I think so. They have very long hairs on
ALAN ALDA And they hear with them?
FRITZ VOLLRATH They hear with their legs. We can have a look
at one of the other spiders and clap our hands and you can
see how they can hear. Oy!
ALAN ALDA Oh yeah, yeah, when you said "oy".
FRITZ VOLLRATH Oy!
ALAN ALDA Look at that.
VOLLRATH Oy! Oy!
ALAN ALDA It's a cockney spider.
FRITZ VOLLRATH That's right. And it's not my breath see? Oy,
oy, hello spider!
ALAN ALDA Yeah, it's not the air, it's the sound. Woo-woo. Woo-woo.
Oy! Oy! This is the first time I've been able to scare a spider!
ALAN ALDA (Narration) Orb webs like these -- the classic spider
webs -- are built anew every night in just a half-hour or
so of labor.
ALAN ALDA I see a web there.
VOLLRATH Oh yes, look at that.
ALAN ALDA (Narration) At first sight, this one also seems unoccupied.
VOLLRATH Ah, she has a huge fly. No wonder that…
ALAN ALDA Oh she's having breakfast.
ALAN ALDA There she goes.
ALAN ALDA (Narration) The spider is the common garden cross spider.
FRITZ VOLLRATH There she is. You can see lots of little new
insects flying into the web.
ALAN ALDA (Narration) The orb web is the perfect device for catching
flying insects, like the fly she's eating now. But spiders
had found a use for silk long before insects even had wings.
VOLLRATH They invented silk about 400 million years ago, long
time ago they invented silk. And possibly to cover the eggs
maybe, or wallpaper a little burrow in the sand that they
ALAN ALDA You mean all this comes from interior decoration?
VOLLRATH That's right. And then of course once you have silk
you can do things with it. For example, you can make single
threads that go out from your wallpapered little house, and
an insect that walks around stumbles on one of these threads
and the thread gives you the information that there is somebody
out there. It's a line on which you have your feet, and you
can feel somebody tugging it and you rush out a go for it.
ALAN ALDA (Narration) When insects discovered flight, spiders followed
them into the air, spinning their snares into webs to catch
insects on the wing -- as well as careless ants. The spider's
silk now has another role -- wrapping the prey, which has
been paralyzed with a venomous bite, for eating later. This
wrapping silk is actually one of seven silks this spider spins
from glands in its tail. Another of these silks, a strong
non-sticky thread, is used to build the frame of the web,
the supporting spokes. Then the spider sets about spinning
the silk that will actually catch her prey -- but not quite
as I'd always imagined.
ALAN ALDA Is all this a spiral? Does it start with just one
line out from the center and go round and round?
FRITZ VOLLRATH That's right. But starting from the outside.
ALAN ALDA The outside?
FRITZ VOLLRATH Now this is… The problem that the spider has
is that it has to build a structure that has to be very sticky
and reasonably soft. If it is too tight, then it could act
like a trampoline. When an insect flies in it, it is flung
back out. So it has to be quite soft and quite giving. But
now imagine, working, precision working, on a trampoline.
It's difficult to do that because everything moves. So what
the spider does, it has a little pretty tough spiral, from
the inside out. And then it builds from the outside in the
sticky spiral and eats the structural spiral away.
ALAN ALDA Wow.
VOLLRATH That means that it ends up in the center, surrounded
by a pristine web.
ALAN ALDA (Narration) Soft yet sturdy, the web can even survive
being poked and torn.
VOLLRATH You can see the rest of the structure is hardly affected
by it. It's a perfect lightweight structure in which the tensions
and forces are distributed in such a way that local damage
does not result in total failure.
ALAN ALDA You just touch it?
VOLLRATH Just touch it and…
ALAN ALDA Oh! What happened? It thought I was a fly!
ALAN ALDA (Narration) Fritz is especially intrigued by how the
spider constructs its sticky capture spiral. Orb spiders have
very poor sight, but they seemed to him to be using their
legs and bodies to make measurements of distances and angles.
By slowing down the video, you can see for instance how the
left front leg reaches out to touch the previous spiral before
the spider attaches the new one. But just how does the spider
turn measurements like these into decisions? Fritz assumed
that spiders possess some inborn set of web-building rules.
The trick was to figure them out.
VOLLRATH What we decided to do there is to take the rules
and encode them into a robotic spider.
ALAN ALDA Some little imaginary spider that just exists on the
VOLLRATH Exactly, a robot that exists in the screen, so we
don't have to worry about the little wheels and the legs and
everything actually working and being oiled. The thing just
lives in the screen. But it is like a robot. It uses the brain
of a robot.
ALAN ALDA (Narration) Enter the cyberspider -- whose brain has
to figure out for itself how to lay down the capture spiral,
using rules Fritz and his colleague made up. This cyberspider's
an expert, reversing direction to keep its web spacing even
-- and like its living counterpart, eating its scaffolding
as it goes. But most of the rules the researchers tried out
produced thoroughly incompetent cyberspiders. So they turned
to the method used by nature.
FRITZ VOLLRATH Instead of us looking at our computer cyberspider
and changing part of the rules and how the rules interact,
we actually programmed that into the life of our cyberspiders
-- because we don't have just one, we have many.
ALAN ALDA You're not telling me you get these cyberspiders to mate?
FRITZ VOLLRATH Absolutely.
ALAN ALDA They meet each other in chat rooms and get together?
KRINK And they migrate. They meet each other in cyberspace.
It's true. Actually on the screen…
ALAN ALDA Little spider bars. How do you actually get two cyberspiders
to mate? What's the real process you go through?
FRITZ VOLLRATH Ah well, we have several cyberspiders in there
that build webs. These webs -- using their rules -- these
webs catch prey…
ALAN ALDA What, do you randomly toss in insects and then you see
how many it catches and you add them up and it gets points
for that? Then it becomes a valuable cyberspider, it's a smart
VOLLRATH A good one with lots of prey is a good one and one
with very little is a bad one. Now the good ones -- there
are many -- the good ones mate and have children which inherit
ALAN ALDA (Narration) Here are six webs built by one generation
of cyberspiders. Each spider has a random selection of cybergenes,
and so different web-building rules. Now the web is sprayed
with cyberprey-- both small and large insects -- and the spiders
that catch the most pass on their cybergenes to the next generation.
Just as happens in nature, some of the genes pick up mutations
as they're passed along.
ALAN ALDA How do you know how much mutation to put in?
VOLLRATH We put in… you have to be a bit clever about that.
If you put in too much you get, you know, monster spiders…
ALAN ALDA Monster cyberspiders. Ah, this is getting good now…
ALAN ALDA (Narration) But with just enough mutation to generate
novel new genes, the webs keep getting better and better.
ALAN ALDA This is wonderful. You have a window here -- on the same
kind of computer screen that I have on my desk, you have a
window into evolution. You're watching evolution take place,
at least a model of evolution.
ALAN ALDA (Narration) This is how one population of cyberspiders
evolved their web through time. Amazingly, Fritz and Thiemo
believe that only two key rules, involving angles and distances,
govern this web-building ability -- a marvelous example of
how simple rules can combine and interact to produce very
complex things. This web evolved in just 50 generations. What
the work suggests, but of course doesn't prove, is that real
spiders also build their webs using these same simple rules
-- creating in the process not only a device to catch prey,
but also an instrument for serenading the opposite sex. Fritz
is hoping this male will demonstrate, by plucking out a love
song on the threads of the web built by the female at its
ALAN ALDA He just seems like he's sitting there limply. He doesn't
seem to be engaged at all.
VOLLRATH He's limp with fear maybe. He has to figure out where
he is in relation to her, exactly where in the web he is.
But he also knows the only way to find out is to walk around.
ALAN ALDA And if he walks around he's in danger of being eaten.
FRITZ VOLLRATH Exactly.
ALAN ALDA Now what's he doing? He's moving his feet, his legs.
VOLLRATH Yes, he might start to play…
ALAN ALDA (Narration) Our male's tentative plucking of the female's
web-strings wasn't unsuccessful, and he ignored Fritz's urgings
to try again. But as we'll see in our next story, the signals
a web can transmit don't always serve the spider's interests
-- they can also lure it to an untimely end.
ALAN ALDA (Narration) In a greenhouse at Binghamton University
in New York State, Stim Wilcox is setting up to record a fatal
confrontation between spiders -- one in its web, the other
-- called Portia -- about to be released from her plastic
WILCOX This is called a Portia Palace of course…
ALAN ALDA (Narration) The Portia spider is a hunter -- of
WILCOX It's amazing, they just sort of lock on like warriors,
with prey in sight and sword raised.
ALAN ALDA (Narration) Now everything happens very fast.
WILCOX: She's signaling. It's perfect. She's stalking. God!
She pounced the prey! If you got that on film, we've got it.
ALAN ALDA (Narration) We're about to find out what just happened.
But first here's Portia alone in all her bizarre beauty --
with headlamp eyes that shine out from a brain filled with
WILCOX: The first step to record is to put the recording device
on the webbing. I've got here a galvanometer with a little
ALAN ALDA (Narration) The needle will pick up the tiniest vibrations
of the web. It allows Stim to literally hear every footstep
of the spider that lives here. But it's the Portia that Stim
really wants to listen to -- because it's the way she exploits
the web to transmit messages that makes her such a mistress
STIM WILCOX OK, Portia's on the web…
ALAN ALDA (Narration) Found most commonly in Australia and Southeast
Asia, Portia spiders don't build webs of their own, but invade
the webs of others. Her arrival on this one hasn't gone unnoticed.
Portia's goal is to get close enough to her host to attack
and kill it.
WILCOX Portia when on a web like this tends to look up and
stare fixedly at you for maybe five to ten minutes before
doing anything else. So I'm just going to try to stay still
while Portia orients herself and decides what to do.
ALAN ALDA (Narration) It's a high stakes game. Every move
she makes sends a message -- and the wrong message could get
her killed. The trick is to send a signal that tempts her
host to investigate but not attack.
WILCOX Portia is now beginning to move around and make palp
plucks with her two little apparent legs up front, and is
in fact signaling that way to try to lure the prey spider
up close to it.
ALAN ALDA (Narration) But this time the strategy doesn't work.
The host spider panics -- and Portia switches its tactics.
WILCOX The left front leg there was making signals.
ALAN ALDA (Narration) Instead of gently plucking the web, it starts
to twang it with its front legs.
WILCOX Notice it's starting to move forward just a little
bit. When it makes these larger jolting signals, the whole
body moves. It becomes what we call a smokescreen signal,
because the frequency that Portia's body makes when it shudders
like you can see there is virtually identical to the waveform
made when a leaf or a twig drops into the web.
ALAN ALDA (Narration) By moving forward as it shudders, Portia
hides its advance behind what seems to the host spider to
be a bombardment of flying objects. It's this ability of Portia
to change tactics in mid hunt that Stim Wilcox finds so impressive.
He's recorded a repertoire of some one hundred different signals
from Portia -- which often tries out first one, then another,
till it finds one that works. This time the smokescreen signals
have brought it within jumping distance of its by-now thoroughly
WILCOX See the front legs come up? Like so -- raised up high
like that, higher and higher. They're way up high ready to…
JUMP. Perfect! Absolutely perfect.
ALAN ALDA (Narration) Every time he witnesses Portia's prowess,
Stim Wilcox almost glows with pride.
STIM WILCOX They are amazing little dynamos of cleverness,
deceit, problem solving, thinking and just plain flat-out
instinct. As a research animal, just from a strictly scientific
viewpoint, it's a dreamboat animal. It's got it all.
ALAN ALDA (Narration) If Portia's got it all as a research animal,
then this -- another of the class of spiders called jumping
spiders -- runs it a very close second. It's a female Maevia,
sharing with Portia a huge pair of eyes up front and three
smaller eyes on each side. Here's a male Maevia, with grey
stripes and bright orange-yellow pedi-palps -- mouthparts
that look like extra legs. When he courts the female he scuttles
from side to side in a ritual shaped by evolution to let the
female know he's a potential mate and not a meal. Now things
get strange -- because this is another male Maevia, black
and white with three tufts on his head. When a female's around,
he too does a mating dance, but his is a sort of "hey, look,
I'm over here!" Only after he gets on OK signal from the female
does he sidle in for the final approach. Dave Clark of Alma
College in Michigan has built a miniature movie theatre to
find out how female Maevias cope with having two very different
males in their lives.
DAVE CLARK She's orienting around the arena. Now she's looking
up at me, kind of checking me out. We're looking eye to eye
at each other right now. And hopefully she'll re-orient to
the grey morph that's courting her. There, just like that.
ALAN ALDA (Narration) What the female is actually watching is a
video image of the grey-striped male. Dave Clark discovered
that spiders treat small-screen versions of their kind like
the real thing when he was one day watching spider movies
projected on the wall of his lab.
CLARK: I noticed that a female in her cage had swiveled and
oriented to the image on the wall. In fact she ran down to
the end of her cage and displayed full blown sexual receptivity
behavior to that male image. And I thought, wow, this is pretty
ALAN ALDA (Narration) In real life, half the male Maevias are born
grey and the other half tufted. At the movies, females are
happy with the video versions of either. This gave Dave an
opportunity to ask a question that had long intrigued him.
What are the females responding to -- the way the males look,
or the way they act? He turned to his computer.
CLARK Here we have our tufted in his phase one posture. This
is all just little objects in here that you use to create
these and piece them together, sculpt them together into a
spider-like shape that you see there. You can also animate
these images as well. Here's a 3-D animation of a tufted male
in phase one courtship. You can do the same thing with our
grey male, animate our grey male. This also provides quite
a bit of flexibility in how you might go about changing the
appearance of these images. And here's our tufted assuming
a posture that it would never assume in nature.
ALAN ALDA (Narration) The tufted is in fact behaving like a grey.
And this grey is waving just like a tufted. Dave can now show
these mixed-up males to females in his spider theatre. Most
females are unimpressed by the tufted males that behave like
greys. On the other hand, they are clearly interested in grey
males that act as if they're tufted. So for the tufted males,
it's their vigorous waving that seems to count rather than
their hairdos -- which fits with the fact that they do their
courting at a much safer distance from the females than do
the greys. Right now both males seem equally successful in
their strategies. But Dave suspects that he may be watching
one species in the act of separating into two -- a magical
moment in evolution that may also be crystallizing in the
next spiders we meet.
ALAN ALDA (Narration) We're in Southern Arizona. After the brief
summer rains, the desert's deceptively green. This is a harsh
environment, posing extreme challenges to the plants and animals
that live here.
Usually what we have is a sort of a permanent sheet that's
kind of large, because these are hungry spiders.
ALAN ALDA Could they be anywhere?
ALAN ALDA (Narration) I'm again looking for spider webs -- this
time with Susan Riechert of the University of Tennessee, who's
been studying the spiders here for 30 years.
ALAN ALDA There's a... there's a web.
Yep, see, you did better than I did.
ALAN ALDA (Narration) It's a funnel web, a flat sheet of silken
webbing extending like an apron in front of the spider's funnel-shaped
They're touching the web and they're feeling the vibration
of anything that might be coming down the web. In addition
they're... picking up airborne vibrations of flying insects
that are moving the air. And so they can tell what kind of
insect that is that's in the vicinity and um... whether they
want to come out and attack it or not.
ALAN ALDA They can tell just by the vibrations on the web or...
or in the air what kind of insect is sitting on their trap,
ALAN ALDA (Narration) These are fire ants. They're tough and aggressive,
with a nasty bite.
RIECHERT Here we go. I'm dropping the ant.
ALAN ALDA (Narration) The spider attacks without hesitation. It's
a female -- summer is breeding season so she has to eat, even
though she's risking her life in the process.
ALAN ALDA She grabs at it then she pulls back.
ALAN ALDA What's she doing when she does that?
She's trying to avoid the jaws of that ant. She's trying to
inject venom. Oh... she has to try and get her little fangs
that are very small in through that hard casing of the ant.
ALAN ALDA (Narration) But it's not just the ant that could kill
her -- the hot desert sun could, too. She'd be protected back
in the shade, but she can't take her prey in until it's subdued
and safe to move. Five minutes into the struggle the sun comes
out. As the web rapidly heats up, the spider's forced to retreat
to its shady funnel. It's now over a hundred degrees out on
ALAN ALDA How does she know the ant will still be there when she
She doesn't. But she doesn't have a choice, because if she
heats up and she goes into a stupor she'll die... she'll get...
she'll cook. But they're hungry so they have to try for everything.
ALAN ALDA (Narration) She's back within a minute for a quick check
on her victim. Now it seems safe to take in. Susan thought
she had her desert spiders pretty well figured out until one
day she discovered the spiders who live up in this canyon.
The canyon's a lush oasis, so biologists would expect the
plant and animal species living here to be different from
the ones coping with desert extremes. But to Susan's surprise,
the spiders were the same. This launched her on a journey
of discovery that's still continuing, and that may eventually
lead to a glimpse of evolution itself in action.
ALAN ALDA Well this is a lot nicer here. I mean, I can see how
the spiders feel about this...
RIECHERT It's better for us, isn't it?
ALAN ALDA Yeah, but I... I can... it's cooler.
ALAN ALDA (Narration) Susan first noticed that, even though it's
cool here, river spiders often stay in their funnels. They're
timid and fearful, unlike their desert cousins. That makes
sense, she realized, because under the trees the enemy's no
longer the sun -- it's hungry birds. But seeing the same species
changing its behavior like this, to fit a different environment,
was a big surprise -- an important discovery in biology.
Let's try an ant, shall we? Let's see... do you see her at
all? If she's there, she's back pretty far.
ALAN ALDA I see something in the tunnel.
ALAN ALDA (Narration) The threat of birds stops river spiders coming
out to fight a tough ant. There are plenty of softer insects
ALAN ALDA There's a definite lack of interest in this ant here.
They're gonna ignore her... the vibratory patterns that an
ant's gonna make. They're not gonna come out...
ALAN ALDA It's not worth the trouble, because you could get killed
ALAN ALDA (Narration) Susan set up a natural laboratory -- an eight-acre
enclosure running from the river up the canyon side. At the
top the lush river environment gives way to dry woodland,
where the spiders are very aggressive -- like those in the
extremes of the desert. For Susan the question was, what happens
when the tough guys above meet the softies below? The first
thing that happens is any spiders heading down into the canyon
are stopped by the border patrol. They come up against the
study area's boundary, and get caught in pitfall traps.
ALAN ALDA I'll check the ones coming from this side...
We'll see who finds the first animal, how's that?
ALAN ALDA ... all right.
ALAN ALDA (Narration) Both sides of the fence are checked, but
most spiders are heading downhill toward the easy life on
ALAN ALDA Ah... there's something in here... oh.... oh geez...
watch out, there's something in there!
RIECHERT Yeah, a cricket or something.
ALAN ALDA What? A cricket?
RIECHERT A cricket, and an itsy, bitsty spider, and...
ALAN ALDA You never know what it could have been. It could have
been a scorpion.
Well, you're losing out on...
ALAN ALDA I don't want it back!
I emptied it.
ALAN ALDA Oh.
You always have to empty all the insects out... when you do
ALAN ALDA You know...
RIECHERT By... by the way, there are scorpions... um...
ALAN ALDA There are or aren't?
ALAN ALDA There are. Of course there are! What do you think I was
So watch your fingers when you reach in.
ALAN ALDA Nothing... something, something! Huh-huh, a spider...
RIECHERT Yeah, probably another cricket...
ALAN ALDA No, no, a spider.
ALAN ALDA Yes.
Let's see. What kind?
ALAN ALDA Very aggressive spider... ha... That's a spider!
ALAN ALDA What is it?
Well, that is an Agelenopsis aperta.
ALAN ALDA I told ya!
ALAN ALDA (Narration) Every day trapped spiders are brought to
the lab close to the enclosure. They'll be returned to the
wild just across the fence, at the point they were caught,
to continue their journey. But first they're put through their
paces. This is a test for aggression. Two males are placed
on a web built by a female who's been removed. Immediately
one male takes possession of the web funnel, looking for the
female. Susan's seen this kind of face-off many times in the
wild. The result can be anything from one spider running away,
to a fight to the death. These are both aggressive, dry-land
spiders so neither is prepared to back down. In fact, after
he's first driven off, the attacker heads right back to the
web funnel. Inside the funnel the defender slowly edges toward
the attacker, who's lurking just outside. They're both looking
for a fight. When it finally erupts it's ferocious. In a surprise
reversal the attacker, now on the left, bites the defender's
leg and hangs on -- it could be all over. But then the defender
pulls free, scares the attacker off and pauses to nurse his
leg. He once again takes possession of the funnel. But it's
not over yet. The defender wants the attacker well clear of
the area. But the attacker stays lurking nearby. This particular
confrontation took about two hours, although Susan's seen
them run for an entire day. The end came like this -- with
a vicious tangle that was going to lead to death, until the
referee stepped in.
I've got them separated.
ALAN ALDA (Narration) Susan doesn't want to lose any of her spiders.
The aim is to score them for aggression, mark them, and then
see how they do back in the enclosure. The contestants will
be returned within the hour. There are about fifteen hundred
spiders within the enclosure, and Susan has caught and tested
every one. Females are kept in the lab until they build webs
in their plastic boxes, then they go back in the field with
the males. Now the study moves to the next stage.
ALAN ALDA You know exactly where it is?
ALAN ALDA It's like, there's a favorite night spot they go to or
RIECHERT Um... no, well, potentially any one of these spiders
that is in a box could be mating. Now, I think if you were
to look inside that funnel you will see...
ALAN ALDA Down in here?
Yes, you will see that there are two spiders.
Oh, yeah yeah. OK.
ALAN ALDA (Narration) There's a mating going on between an aggressive,
dry-land male who came down the hill, and a timid river female.
It would have gone something like this, with the male cautiously
approaching while doing his mating dance, to signal his intention
to the female. Both spiders have to be careful because things
can turn ugly pretty quickly. A fight could start, especially
if male and female are very aggressive. Or if one's too aggressive
and the other's too timid, then the timid one might simply
run away. But in this case wedding bells ring out and the
tough, dry-land male wins his shy bride from the river. The
happy couple will be blessed with about three hundred kids.
Susan's been following the spiders in her enclosure for twenty
years now and she's run into a puzzle -- the spiders just
aren't behaving right.
ALAN ALDA Right there?
ALAN ALDA (Narration) Many spiders are much more aggressive than
makes sense here. Susan's figured out they are the hybrid
offspring of aggressive, dry-land males and timid, river females.
ALAN ALDA That really seems aggressive. You think that's a
RIECHERT It's gotta be. I mean, here's a spider that obviously
isn't hungry. She takes these ants, that could kill her, into
her funnel and she lets them go.
ALAN ALDA Just catching them for no reason? And they're dangerous
And she probably won't even eat it.
ALAN ALDA (Narration) Here's the kind of super-aggressive behavior
by the hybrids that Susan discovered. Dangerous fire ants
are pulled into the funnel without first being subdued. Not
even a hungry desert spider would take this risk, and sure
enough, Susan's found most hybrids don't make it. Many are
taken by birds, many don't breed because they scare off their
partners. So now Susan predicts a new behavior will evolve
among the river females, that prevents them from mating with
aggressive males. The offspring of those females would survive,
unlike hybrids. If she's right, she'll see much more of this
-- a male with no partner.
RIECHERT Hey Terry!
You got something Susan?
Yeah I'm at A134 and I have a male. It looks like ah... white,
He was there last check.
The female is... ah, not here, so he must have chased her
ALAN ALDA (Narration) Susan expects that somewhere there's a timid,
river female who won't mate with an aggressive male from up
the hill. Her offspring will inherit that behavior, they'll
thrive, and eventually they'll take over the canyon. They'll
never mix with the guys up the hill again. It'll be a shift
to a new species of spider -- evolution in action. To make
that discovery Susan Riechert's prepared to put in another
ALAN ALDA Do you ever at night before you go to sleep say to yourself,
wouldn't it be great if in the next few months I started to
see this shift.. and I... I was there to experience it?
Oh... we'd all love to have that kind of... ah.. event happen.
But... that's nature. It does what it wants. Whatever happens,
happens, and we can just follow it.
ALAN ALDA (Narration) A tributary of the Rio Napo in Ecuador --
itself a tributary of the Amazon. In a journey that moves
from motorized canoe to dugout, two arachnologists are doing
what arachnologists love most -- searching for spiders. Letitia
Aviles was born in Ecuador. Rick West is here from British
Columbia. And this is one of the biggest spider webs in the
AVILES This is a pretty good size nest, not the largest one
WEST Looks like it's about 10 or 12 feet across.
AVILES One can estimate how many spiders there are in there
by measuring the cross section of the nest, and there is a
very good correlation between the number of spiders in the
nest and the cross-section.
WEST How many individuals would you estimate would be in that?
AVILES Yeah, I imagine this colony might have between five
and eight thousand spiders in it.
ALAN ALDA (Narration) The spider is Anelosimus eximius -- out of
39,000 known spider species, one of only 17 that live together
in colonies. This nest has webbing that stretches 20 feet
or more up into the surrounding trees.
WEST Within the one colony, are all the individuals related?
AVILES Yes, they are. The colonies get initiated by sometimes
just a single female. And then they remain within the nest
until they mature and then they mate with nestmates.
ALAN ALDA (Narration) Letitia Aviles began studying these spider
colonies when she was a graduate student.
AVILES It's really wonderful to be working on an organism
that happens in my country, especially to have started working
on them while I still lived in Ecuador, because I was able
to come to the field year round as frequently as I wanted
and that way I got to learn a lot of things about their lifestyle
that I don't think I would have been able to figure out if
I'd been coming here only for a month every year. And with
that basis, now that I live in the States, I already know
enough of the biology to know what it is that I can do and
cannot do with them.
ALAN ALDA (Narration) On this visit, Letitia and her graduate students
are doing an experiment to find out why some colonies grow
large, others stay small, and still others abruptly go extinct.
The spiders from this colony are destined for a new life elsewhere.
AVILES I think this colony contains mostly adults and some
ALAN ALDA (Narration) The experiment begins with sorting the spiders
into different age classes -- and then counting them -- one
at a time. These are adult females, which usually outnumber
males ten to one. Deep within the forest, Letitia plans to
release some of the captured spiders to see what sort of new
colony they build.
AVILES We're going to put them a little bit below so that
when they start building they're going to build up.
ALAN ALDA (Narration) She starts with juvenile spiders, which immediately
and enthusiastically begin laying out the silken threads of
a brand new nest. And almost at once, they claim their first
prey. Next come the adults, which join in the frenzy of new
construction. We'll check back later to see how Letitia's
new nest is progressing. Meanwhile, Rick West is off in search
of his favorite spider.
WEST A lot of frogs and cockroaches in here so there's a good
food source. Also, they like to use burrows around the buttress
roots of these trees. Ah, there's a nice burrow. And it's
got a big tarantula in it, too.
ALAN ALDA (Narration) Rick digs with his knife at the back of the
WEST …something to prod her out. There she comes. What a beauty.
ALAN ALDA (Narration) He's handled hundreds of tarantulas -- and
so far has never been bitten.
WEST This tarantula is an adult female. It's Megaphobema velvetosoma.
Near the front of the underside of the body you can see the
fangs, There's two of them. They're about half an inch. And
they're used for stabbing -- they actually stab their prey.
ALAN ALDA (Narration) The back of the tarantula is covered with
tiny hairs, barbed like harpoons.
WEST When they're scraped off -- she uses her rear leg and
there are some very stout spines -- and she'll scrape these
over the top of her abdomen very quickly and cause these hairs
to scrape off just like I'm doing here. And you can see them
floating away here. And those float in the very fine air currents
set up by the legs and, boy, I'll tell you, when these land
into your skin, they cause a great irritation.
ALAN ALDA (Narration) While Rick's been showing off his tarantula's
weapons of attack and defense, Letitia has been checking her
brand new spider colony.
AVILES Oh, it looks like they did pretty well. They have been
working, it's less than 24 hours since we set up the spiders,
and they have already built a complete nest.
ALAN ALDA (Narration) The nest includes a huge skein of webbing
reaching up into the trees. Its job is to capture prey for
the nest's inhabitants.
AVILES Oh, they've caught some prey overnight, and there's
a group of spiders feeding on it right now. And it's not necessarily
the same individuals that caught it that are going to feed
ALAN ALDA (Narration) This ability to capture and transport much
bigger victims than a single small spider could may be one
reason for the spider's collectivist lifestyle. Unlike social
insects, these spiders don't have specialized tasks within
the colony -- everyone does everything. The thousands of individuals
in each nest stay together throughout their lives and through
the generations -- with just occasionally a single female
or small group setting off into the outside world to found
a new, daughter colony. Letitia wants to know when, why and
how this decision to found a new nest gets made: questions
she hopes this colony and others she is setting up in different
parts of the forest will one day help answer.
WEST I'm just going to examine this burrow. There's a silken
tube on the side of this tree and it looks like it's occupied
ALAN ALDA (Narration) Rick is off climbing trees, armed with a
tiny video camera.
WEST Looks like there's a nice large female. Looks like she's
coming down the burrow now. She senses the camera as a possible
intruder and she's coming to defend herself.
ALAN ALDA (Narration) Frustrated, the tarantula turns from attack
WEST She's turning around. She's going to cover her entrance
ALAN ALDA (Narration) This is a task tree-dwelling tarantulas routinely
perform during daylight hours, sealing their burrows not against
prying cameras but parasitic wasps. But with tarantulas, there's
always that one big question.
LETITIA AVILES You seem to not be worried about the tarantula
biting you. Is it unusual for a tarantula to bite?
WEST It sounds morbid, but I've tried to find at least one
human mortality from a tarantula bite, and there's none. If
it bites you, the pain is purely mechanical at first and then
there's a burning sensation -- I've been told, I've never
been bitten -- but I've been told that the burning sensation
lasts for two hours and then goes away. So this is an Ecuadorian
spider, you're an Ecuadorian lady, is this the first time
you've held a tarantula?
AVILES It is the first time I've held a tarantula. A lot bigger
than the spiders I work with. Like a teddy bear walking on
you actually. Pretty soft.
ALAN ALDA (Narration) Rick
West can't resist trying to infect everyone he meets with
his enthusiasm for tarantulas. But he's about to meet his
RICK WEST This is Rosie. She's a Mexican red-kneed tarantula.
This particular species is protected by law, you can't capture
them in the wild and sell them for the pet trade.
ALAN ALDA What do you do with a pet like this? You can't put a
leash on it and take it for a walk.
RICK WEST It doesn't bark or chase cars, I know, but they
make the ideal apartment pet, I've heard. You can give it
a cricket and a cup of water and go away for a month and come
back, it's fine. But, bottom line is, it's just a large spider.
ALAN ALDA (Narration) But for Rick, apparently not large enough.
WEST This is one of the largest tarantulas in the world. She
comes from Venezuela. She is a little nasty, you can't handle
her. But when you think of her as a spider, it's absolutely
ALAN ALDA I don't know which one to worry about. Now I'm not
worried about Rosie so much. This is very clever of you. That
is a big animal.
RICK WEST Isn't that something?
ALAN ALDA Would he attack this other spider?
WEST Yes, and actually kill it and consume it.
ALAN ALDA (Narration) And as if I'm not sweating enough already,
here comes another one, recently discovered by Rick in Mexico,
and named by him, astonishingly:
RICK WEST Hapalopus aldanus, and I named it in honor of yourself.
ALAN ALDA I'm shocked.
ALAN ALDA (Narration) Rick obviously doesn't know of my history
WEST And at the back it's got what the species name is and
a little bit about it.
ALAN ALDA Fantastic. Hapalopus aldanus. If you had named any other
species after me I'd be delighted and have this little inner
glow. I'm sorry to say -- since this is your life's work --
with a tarantula I have completely blotted it out of my mind,
and it's only been two minutes now since you've named this
species after me. I'm really sorry.
WEST Well, that's it, I'm disconnecting the mike, we're out
ALAN ALDA (Narration) A day in the life of an arachnophobe.
SAKELARIS That would be my standard gear regardless of what
time of year it was. When I did laundry, the moment that I
got them from the drier I would put them in a plastic bag.
I had the cleanest truck because I had a spider brush and
I would literally brush my truck every single time I got in
it. I had also a special spider brush and I would like wave
it around in case there were webs hanging on the wall all
the way down the hall to my bedroom.
ALAN ALDA (Narration) For Joanne, avoiding even the slightest glimpse
of a spider had become a full-time obsession.
ALAN ALDA You tried a number of things, right? And then what? How
did you get the idea to work on virtual reality?
SAKELARIS Well I saw Scientific American Frontiers on Channel
9, with you…
ALAN ALDA The room is tilted…
ALAN ALDA (Narration) In the show Joanne saw, we visited researchers
at Georgia Tech in Atlanta. Using virtual reality, they are
able to give people with a fear of heights a simulated version
of the real thing.
ALAN ALDA Oh, you know what I hate is looking up.
LARRY HODGES That's what I've always said.
ALAN ALDA (Narration) The idea of VR therapy is to provoke the
anxiety of the phobia, then help the patient cope with it.
ROTHBAUM You want to give me a rating?
CHRIS CLARK Twenty-five.
ROTHBAUM Just because you feel something in your body when
you're up this tall doesn't mean that it's fear; just means
ALAN ALDA (Narration) After several sessions of VR treatment, our
patient was even able to take a ride in a glass elevator.
ALAN ALDA And you saw that show, and what did you think to
yourself, what was your reaction to that?
SAKELARIS I thought it was cool that the guy was going up
in that elevator. And I was looking at his eyes and going,
oh, he knows, he knows the feeling.
ALAN ALDA (Narration) Joanne Sakelaris, who lives in Seattle, went
to her therapist and asked if virtual reality was being used
to treat arachnophobia. He contacted a VR researcher at the
University of Washington, Hunter Hoffman.
ALAN ALDA You can make it a little tighter.
HUNTER HOFFMAN Oh, OK. That better?
ALAN ALDA Yeah, yeah.
HOFFMAN Now, if you hold your hand out, you should be able
to see your…
ALAN ALDA I see my hand.
HUNTER HOFFMAN Cyberhand.
ALAN ALDA My cyberhand, OK.
ALAN ALDA (Narration) Within a few weeks, Hunter adapted an existing
VR environment into one that's an arachnophobe's nightmare.
HOFFMAN If you can just move over toward that vase.
ALAN ALDA There's the vase. Oh my…! There's a spider! What's that
spider going to do?
HOFFMAN It's unpredictable.
ALAN ALDA I really did react to that little thing wiggling its
HOFFMAN What was your anxiety when you first saw it?
ALAN ALDA (Narration) Watching me along with Joanne is her therapist,
ALAN ALDA From zero to one hundred. Oh, I don't know, about 20
or 30. I mean I had a little startle reaction. I got used
to it right away because it's clearly virtual. But there's
something about that shape that I have an automatic reaction
HUNTER HOFFMAN So try to herd him into that sink.
ALAN ALDA Into the sink?
HOFFMAN Yeah. So you just have to bend your knees so you can
see him. Yeah there he goes, now push him into the sink. There
he goes. Now see those little red and blue buttons just to
your left? Touch those and it'll turn the water faucet on.
Now touch this apple…
ALAN ALDA Poor guy. Why didn't we just throw him out a window?
CARLIN Well, he comes back.
ALAN ALDA Well then forget about it.
HOFFMAN Let's take a short break.
ALAN ALDA All right. Well, am I cured now?
CARLIN You're the best judge.
ALAN ALDA How will I know if I'm cured?
CARLIN We'll find out.
ALAN ALDA You're not going to give me a real spider, are you?
AL CARLIN We'll see what happens.
ALAN ALDA What was it like watching me go through this? Did
that bring back the process for you?
SAKELARIS Yeah, because my hands got sweaty watching you.
HOFFMAN Now that you've achieved some level of desensitization,
we move to the next stage.
ALAN ALDA Is the spider going to get worse, is that it?
HOFFMAN Can you see OK?
ALAN ALDA (Narration) Now at this point, you know more about what's
going on than I do, locked away as I am in my virtual kitchen.
ALAN ALDA What is he, on a thread or something?
HUNTER HOFFMAN He's on a spider web. So what's your anxiety
from that spider?
ALAN ALDA I have to tell you that I consciously don't feel a lot
of anxiety, but I'm noticing that I feel here in my chest
and my stomach, I really feel a physical reaction.
CARLIN So just keep looking at it, and if you can, try to
take a deep breath, hold it for a moment and breathe out slowly.
ALAN ALDA Where'd he go? Oh, he went someplace, up and down. I
don't like it when it gets out of my sight.
HUNTER HOFFMAN If you can just reach out and touch the spider,
with an open hand.
ALAN ALDA Open hand. Aah.
HUNTER HOFFMAN Are you OK with that?
ALAN ALDA Yeah, yeah. Ah! You know what just happened? You
put that thing in my hand, that controller, but you were holding
it right where the spider was. And when I put my hand over
there, and there I got that controller, I thought I was touching
HOFFMAN OK, try touching that again.
ALAN ALDA You didn't do that deliberately did you?
HOFFMAN Try touching that again.
ALAN ALDA Where is it? Ah…
HOFFMAN So did that feel like a spider when you first touched
ALAN ALDA Yes of course it did.
HUNTER HOFFMAN So what was your anxiety then?
ALAN ALDA Well, I think my laughter was an expression of my
ALAN ALDA And I didn't know what it was. It was a shock. It must
have been 60 or 70. Ah, this is disgusting.
HUNTER HOFFMAN OK.
ALAN ALDA Ah, it's a tarantula, too. It's very interesting. The
longer we do this, the more convinced I am that I'm deeply
anxious about this, and you're not going to get me out of
CARLIN I suspect that with time you'd get real comfortable,
almost sort of bored with this virtual spider. But hopefully
if you're somewhat anxious along the way it may move you to
be less destructive to those guys when you meet them in the
real world. The may never be your favorite critters…
ALAN ALDA But I can learn to coexist with them.
AL CARLIN You can learn to coexist and I think also to learn
to be less troubled by the visceral response you have to them.
ALAN ALDA Is this something you could have done before you had
ALAN ALDA (Narration) Since Joanne came up with the idea of VR
therapy for arachnophobia, the program has been extended and
is now being offered to others.
ALAN ALDA You wouldn't even have been able to look at a field?
And here you are walking through it.
JOANNE SAKELARIS I know.
ALAN ALDA And what are you experiencing?
JOANNE SAKELARIS Nothing!
ALAN ALDA Really?
JOANNE SAKELARIS Joy. I can't explain it, it's so… I went
camping, and I've never been able to go camping before, and
I mean that for me that was… great.
ALAN ALDA (Narration) Not only can Joanne now go camping -- she's
even ready for a visit from Rosie.
WEST I understand you had a real fear for tarantulas at one
time? And you've overcome that, do you think?
SAKELARIS Yeah, I'm confident.
ALAN ALDA (Narration) This is someone, remember, who could spot
a tiny spider 50 feet away -- and fly into total, uncontrollable
SAKELARIS This is so cool.
RICK WEST Can you feel the little claws on the end of her
feet? They're like a cat foot.
ALAN ALDA (Narration) As for me, my mind is filled again with
visions of that tarantula I struggled with in the swimming
pool as a kid.
SAKELARIS This is cool.
ALAN ALDA When it started to crawl up your arm, I was cringing,
and I thought, how can she tolerate that? And you're the one
who had the problem. And I'm sitting here thinking I'm going
to go out of my head if you let that crawl any further up
ALAN ALDA (Narration) I don't know if it was the VR therapy or
just Joanne's bravery, but… here goes.
ALAN ALDA She's got the softest touch, you know.
ALAN ALDA (Narration) And so, having learned in the last hour to
appreciate spiders, I finally make contact.
ALAN ALDA Well, my heart's not pounding, too much. I can't breathe,
but my heart's not pounding.