David Attenborough interview

Attenborough is sitting in his elegant Richmond garden, surrounded by a plethora of nesting boxes, a pond that is home to crested newts and damson flies, and a great cherry tree that he planted 50 years ago. Tracked to his own lair, the naturalist remains endlessly enthusiastic about his new subject. Some of these creatures are more exotic than any other type of life form on the planet, he claims - a consequence, in part, of their fast-lane evolution. Species for whom a day is a lifetime can churn out dozens of generations in a year. Thus the forces of natural selection will manifest themselves at a far greater rate than they will with long-lived creatures such as elephants and humans.

In addition, terrestrial invertebrates - which are defined simply as creatures that lack a backbone - have existed for 400 million years compared with mammals who first appeared about 100 million years ago and who are, frankly, a bunch of Johnny-come-lately additions to the animal kingdom. In combination, this length and speed of evolution produces some astonishing effects.

Consider the spinning of silk. Its gossamer strands are as strong as steel and the ability to make the stuff appears to have evolved independently in invertebrates on several different occasions. In some cases, silk is used simply to wrap larvae to protect them. In others, its employment is truly astounding: principally among spiders. Attenborough has two favourites: the bolas and the gladiator, both found in North America and Australia.

'The bolas does not use silk to make a web. Instead, it hangs from a strand like an acrobat. When a moth comes near it, it throws out a line of silk with a gluey blob at the end. This sticks to the moth and the spider reels it in. As for the gladiator spider, it makes a little cat's cradle web, which it holds in four of its legs. It then hangs by a thread above the ground. When an insect passes by, it drops the net over it and bundles it up. These guys are real operators.'

Attenborough's enthusiasm for the living wonders of our planet has been the defining feature of a career that is one of the most distinguished in the history of broadcasting. After gaining a zoology degree at Cambridge, he started out as a trainee producer at the BBC in 1952 and, after a couple of years, began making 'Zoo Quest' which ran for ten years. It was here that Attenborough per-fected his now legendary hushed and serious monologues as he crept after some unsuspect-ing species - a dozing wombat or grooming gibbon - that was about to be bundled up and shipped off to a new home.

In 1965, he quit natural history to become a penpusher, taking over the post of controller of the new TV channel BBC2 before he was made the BBC's director of programmes in 1969. He was a highly successful administrator but disliked the bureaucracy and the constant schedule of meetings, describing his work then as'absolutely beastly'. So he quit (in the process turning down the chance to be the BBC's director general) and took to the road again, or, more precisely, to the savannah, the ice floe and the desert.

Thus began David Attenborough's magnificent explorations of the grandeur of nature. The first, Life on Earth, is still rated as one of the finest products of public television broadcasting. It has been seen in an estimated 500 million homes across the planet, and has been sold in book form in equal volumes in more than 100 countries. This was followed by The Living Planet, Trials of Life, The Private Life of Plants, The Life of Mammals - and now Life in the Undergrowth, which will accompany the BBC TV series to be screened in October and November.

'It is all part of a pattern, I suppose. The only trouble was trying to find the right name for the book. I still don't know if it is a good touch or not. You can't call it "The Life of Terrestrial Invertebrates", that is too cumbersome. You can't call it "The Life of Insects" because that would exclude all invertebrates that don't have six legs, such as spiders, which have eight, and centipedes, which have about 50, and these are some of my stars. I also didn't want to baby-talk viewers and call it "The Life of Creepy-Crawlies". So "Life in the Undergrowth" it has become.'

Taking on the denizens of the dirt and the dark is asking more from his readers than normal, Attenborough admits.'There will be more resistance from readers, I know that. You know the prejudice: two or four legs is good, anything more is bad if not terrifying. However, I cannot go on writing books and making films about elephants and chimpanzees all the time.'

The time was right for terrestrial invertebrates not just chronologically, however. There is also the issue of technology - digital techniques have recently progressed to such a state that they allow the photo-graphing of ants, spiders and scorpions in as much detail and depth of field as used to be possible in filming a lion on the savannah.'Lenses are smaller than match-heads, servo mechanisms linked to computers let you track insects in action, while cameras' incredible sensitivity means you don't have to flood an insect colony with light to photograph it and fry the poor little buggers in the process.'

The net result is some of the most stunning images ever taken of the insect world, adding a lavish and dramatic lustre to Attenborough's book. One favourite encounter, photographed in graphic detail, is described by him in terms that would do justice to The Odyssey.

'Matabele ants are ferocious warriors with great shear-like jaws that live entirely by preying on termites. Every morning, a raiding party of 200 to 300 sets off from their underground nest, on a trail laid down by scouts, towards a particular termite hill. The termites know these buggers are coming and their soldiers, all big brutes, line up to defend their colony. But they are no match for the Matabeles, who storm the termite hill galleries like storm-troopers. They attack the defending soldiers by grabbing them and stinging them in the only place they lack armour: their mouths.

'You can see each termite soldier shudder and collapse. Then the ant throws the carcass out and it is shipped off by worker ants. But what is really amazing is that you can now listen to the different sounds the Matabele ants make as they depart and return. Each act has a special sort of chorus. It's as if they are singing "Hi ho, hi ho, it's off to work we go" as they set off.'

Such encounters reveal the extraordinary nature of the tiny world of the invertebrates, though theirs was not always a diminutive existence, says Attenborough. The first of these creatures to crawl from the sea were huge. Four hundred million years ago, 4ft scorpions were scuttling around the lichen-covered landscape. A little later, 3ft dragonflies appeared on the scene.'Then the invertebrates started to shrink,' he adds.'It was probably connected with the arrival of birds and large vertebrate animals. The invertebrates shrank because this made them less vulnerable as prey.'

Life in the Undergrowth is a fairly fantastic affair, in other words, and well worthy of readers overcoming their aversion to the multi-legged appearance, says Attenborough.'They were the first land animals and they have created the ecosystem in which we live. That's pretty important.'

The new book will form the penultimate chapter in Attenborough's explorations of the wonders of life on Earth. All that is left is his next project - amphibians and reptiles - and that will be that. Although still startlingly boyish for a man who will be 80 next year and still capable of nipping around the world, he recognises his limits, he says.

'I have done ocean creatures, mammals, birds, and plants, and when I have done amphibians, that will be it. I will have created a set of books and about 70 hours of video or DVD that provide a snapshot of what life was like on Earth in the late 20th and early 21st centuries. That will be my legacy. I suppose that is a kind of vanity, but at least it has kept me out of the betting shops. 'After that, I will have to hang up my boots. It would be an impertinence to hope to go on after that. I will be 84 or 85. I just hope they have invented a motorised Zimmer frame by then.'