National Geographic: Panama Wild - Rain Forest of Life Page #4

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But when other juicy edibles

become scarce...

...baby dipteryx does end up

on the menu.

The parent tree has spent centuries,

growing hundreds of feet and

preparing millions of fruit,

so at least one offspring will

survive to reach the canopy.

Yet all that effort can be

gobbled up in seconds.

It will never survive being

stripped bare.

And even those who remain intact

need luck to prevail.

They must have light to live.

And light is hard to come by

on the forest floor.

Each and every ray must penetrate

layers of foliage to reach

a seedling below.

Animals can search out light,

but the seedlings, rooted in place,

must wait for the sun.

They make do with sun specks that

flicker over the forest floor,

illuminating them for

just minutes each day.

Even if it gets its moment

in the sun...

...the fall of a single leaf

can seal a seedling's doom.

A new day in the forest sometimes

brings disaster.

If a new tree is to thrive,

another must fall.

For the plants that have struggled

to survive in its shadow,

perhaps for decades,

this is a reprieve from

a dark prison.

A light gap has been torn

in the fabric of the canopy.

It has been centuries since

this spot saw broad daylight.

For seedlings starved for the sun

it is a chance to grow and flourish.

A race for the life-giving light

has begun.

There will be winners and losers

as each plant tries to crowd

out its neighbors.

Into the new light comes

another creature,

biologist Phil Devries.

Phil studies the world of

the light gap

and he's discovered some astonishing

relationships here.

Since I've been a small child

I noticed plants and

I noticed insects.

I like being in nature and

I like forests a lot.

I can think of nothing more

enjoyable

than being surrounded completely

on all sides

and I literally mean up, down,

any direction

with life and that's what being

in a tropical rain forest is

all about.

His love for this forest world

is neatly matched to his quick eye

and insatiable curiosity.

I observe as much as I possibly can,

and effectively what

you're doing is you're asking,

"Hello organism,

what are you doing for a living

and who do you interact with while

you're out here doing your duties

as a butterfly or an ant or

a lizard or a plant?"

I can use butterflies literally

to move around in the forest

and tell me what

the vegetation is like.

Phil has uncovered a light gap plant

called a croton

that's developed an unexpected

relationship with

two different insects,

an ant and a butterfly caterpillar.

Croton provides sugar secretions

which attracts ants to

little nectaries,

and the ants when they're

on the plant...

...deter herbivores,

that is insects that eat leaves.

The plant actually uses ants

to guard its vulnerable leaves

bribing them with a sugary nectar.

The ants keep away any insect

that might do their meal ticket harm.

However, this is really what

I'm looking for.

It's an herbivore as well,

but the ants don't bother it

because it produces sugar

secretions of its own.

The butterfly caterpillar uses

its sugar secretions just

as the plant does

as a tasty bribe.

It keeps the ants well-fed in

exchange for their protection.

Back to ants & caterpillar

The funny thing about this

butterfly caterpillar is that

it bribes these ants with

a sugar secretion

and the ants act like guard dogs

and help protect it from

it's own predators.

In addition to producing sugar

secretions for the ants,

this caterpillar has another trick

that's even more magic.

Phil has made another remarkable

discovery.

These caterpillars can actually

sing.

To capture this amazing talent Phil

has designed special audio

equipment to record its calls.

This gear I have here is

an amplifier and a very,

very sensitive microphone.

I use this to listen to well,

basically, sounds that nobody

else can hear,

and I'm listening to this

caterpillar singing at the moment.

And how these caterpillars produce

their songs are pretty interesting in that on the top

of their head there are long bridges,

and right above the head

there's a collar where there are

two little rods,

and the two rods beat up and

down on top of the head,

and then the head moves in and out,

and these little rods have

little rings in them,

and what they do is they hit

the top of the head,

and then it's rasping back

and forth like a Latin American

percussion instrument...

Caterpillar on mic,

Phil's fingers move it to branch

I think it's fair to say,

without gloating too much,

I have the world's largest

collection of caterpillar calls.

Now let's see what happens

when we reintroduce this

caterpillar to the ants.

Upon its return,

the caterpillar puts its musical

ability to another surprising use

mimicking the calls of ants.

The ants respond as we would,

if we heard a cry for help.

They rush over immediately.

And help is always welcome.

Danger is never far away.

This guard ant earns its keep.

An assassin bug could skewer

the caterpillar and suck it dry.

But it's no match for the ant.

A parasitic wasp fares no better.

In the tropical forest,

every creature lives within

an intricate web

shifting always between harmony

and struggle.

The lesson that I've learned is

that it's probably just scratching

the surface of the number

of interactions that you have in

any light gap in the tropics.

The picture that emerges from

there is of staggering complexity

when you think about

how many species...

there are of plants in the tropics,

and insects in the tropics.

It's very humbling to realize that,

even though I know a little bit

within the context of

a tropical rain forest,

I know absolutely nothing.

This little dipteryx, of course,

also knows nothing of the complex

network of relationships

that have brought it into the light.

So far, it has beaten the odds.

And if its luck holds out,

it may someday become

a forest Titan itself.

Dipteryx, large and small,

is at the heart of

a glorious pattern of forest life.

Unveiling this grand design

remains the quest of the scientists

of Barro Colorado Island

a labor of love,

and a journey of many lifetimes.

Perhaps centuries from now,

the forest will still be here

and scientists will

still be working in

its green depths

when our tiny seedling finally

takes its place among the giants.

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