I went down to give a seminar at Austin, Texas, and I thought, well, I'll tell them about this game theory stuff. So I described to them what I'd been doing, and right at the end, I described this ownership game, and said, 'Of course, I don't believe animals actually do this, but, you know, if they'd read my paper I'm going to write, they should do, you see.' And when I sat down, a man I've loved ever since, tall, lank Texan, called Larry...

[Q] Gilbert

Gilbert, that's right, my neurone for remembering names popped out about - several years ago now - got up and described how for his PhD, he'd worked on a butterfly called Papilio zelicaon, in California. And his story is that the males fly uphill, during the mating season, they fly uphill and they occupy hilltops. And a female who wants to mate flies uphill to get to the top of the hill, and she'll find a male at the top of every hill and she mates. The trouble is, there are more male butterflies than there are hilltops, so the guys who find the hilltops first are the... the 'owners', and any other butterfly that comes along, any other male who comes along, there's a brief spiral flight, and by marking them, he discovered that the intruder goes away and the owner of the hilltop stays there. And then he got two butterflies who believed they owned the same hilltop, by giving one of them the hilltop to occupy on Mondays, Wednesdays and Fridays, and the other one on Tuesday, Thursday and Saturday, and then on Sunday, they were both loosed on the same hilltop. And they went in for a great long fight, they both thought it was theirs, you see. And he described this, and I thought, he's right. It was the first time, I think, I actually thought I was on to something, that such an abstract piece of reasoning that I'd gone through actually seemed to be telling us what animals do. And since that time, the game theory thing has turned out to be relevant to everything from viruses to, you know, to plants growing to all sorts of things, they don't have to be animals. And it's now being very much involved in the whole communication thing. But it is odd that I - it wasn't one of those things where I thought I'd solved an important problem, it was some old thing where I thought I'd solved a really very trivial problem, and then gradually began to realise that the method could be used for solving a whole slew of problems, and as you know, probably is nowadays.