The Brazil Nut Gardener
Given the size of the brazil nut pod, you may expect something large. But the animals that can handle it is actually rather small. It's a rodent
called an agouti. She may look insignificant but her actions have a very significant impact on this rainforest. She specialises in eating tough seeds
and nuts. Thanks to her teeth, which work like chisels.
So this is how they are meant to be opened! That nut is packed full of energy and nutrients. After all, it contains everything you need to start
growing a Brazil nut tree.
And what happens next is the bit that I'm really interested in. Because there are so many nuts in the pod, she can't eat all of them in one go.
She's saving the rest for later. The question is, where is she going to put them? Look at that. She's even putting every leaf back where she found
it. Each nut is being carefully carried away to a different hiding place. As far as she is concerned, this is the ideal place for a larder. And by
complete coincidence, as far as the tree is concerned, this is the ideal place for its seeds to germinate.
Here is one of our marked nuts. And the mother tree is hundreds of metres through there. So the tree, a plant, has managed to get a mammal to bury its
seeds with just as much care as a really good gardener. It's one of those magical rainforest relationships. And the best thing about it is that she has
no idea how important she is. The agouti is the only animal that can disperse the seeds of the brazil nut tree, so the brazil nut tree is completely
reliant on the agouti. It's a case of what we call species specific dependency.
I can guarantee that every brazil not that you'd ever cracked open has come from a tree that was planted by one of these animals. That's fantastic.
You've got to admit, ecology is fantastic.
Euglossine, The Orchid Bee
It's clear why the brazil nut tree needs an agouti. But how does the orchid that I found fit into our story? Like many flowers, it uses pollinating
insects, bees. In fact these orchids use a very special group of these called Euglossine or orchid bees. And more specifically, they have to be males.
Unlike most bees, which up after nectar, this one is after something quite different. He's after perfume. He collects a waxy secretion by rubbing his
legs all over the flower. And in doing so, pollinates that flower. Collecting this perfume is so important to a male orchid bee that it may fly miles
all over the forest in search of it.
The reason that he's collecting scent is that the males compete with one another using smell. They have a sort of a scent-off. The one with the best
bouquet of perfumes gets the right to mate with the females.
But what has all of this got to do with her story of brazil nut trees and agoutis? Only the male orchid bees pollinate the orchids. To reduce
competition between the sexes, the males and females have evolved different niches. It's another example of the extreme diversification that
takes place here in the rainforest.
So the females pollinate a completely different species. A very, very much larger one. The one that I'm sat on. The brazil not tree.
Brazil Nut Tree Flowers
Once a year, the tips of the brazil not tree branches are adorned with a large white flowers. They attract insects from all over the forest.
Including the much larger female orchid bees.
The nectar is hidden beneath a special petal. And the female orchid bees are one of the few insects that are big enough and strong enough to
open the flowers. A small bee, on the other hand, simply doesn't have the strength to open it. This selective door policy is the tree's way of
ensuring that it will only be used by insects which are guaranteed to visit other Brazil not tree blooms and then pollinate them.
The intricate relationship between the male orchid bee and the flowers is the reason that Brazil not trees like this one can only grow in intact
rainforest ecosystems. Now, the Brazil not tree needs the agouti, way down there, to disperse the seeds. The agouti needs the female orchid bee up
here to pollinate the flowers so those seeds are produced in the first place. The female orchid bee needs the male, which in turn leads those orchid
flowers. That's why the Brazil not needs the orchid.
This wonderfully complex web of connections has all come about due to the sheer biodiversity of rainforests. And understanding it reveals the natural
world in a very different light. Animals don't simply live in forests. They are the forests. And forests without orang-utans and elephants are broken
ecosystems. We might want to save rainforests for the elephants, when really, we see bee saving the elephants for the forest. We've been motivated by
what an orang-utan looks like, we should be motivated by what it does.
Stretched out around me is the most complex ecosystem on our planet, home to millions of different species. And whilst there is a wonder in the detail
of the individual lives, nothing competes with the sheer beauty of the bigger picture. The dynamic, functional, living, breathing rainforest. For me,
science is the art of understanding truth and beauty. Well, here's the beauty. And we've seen just a little of its truth.