Star turn

Kam Patel listens to the man who once told Ken Livingstone to name a London park after his favourite all-female snails.

Geneticist Steve Jones does not drive a Renault. He wants his life science students at University College London to know that from the start. He may be in a television advert exhorting the "evolutionary" merits of the Laguna, but he does not own one.

By the end of his first lecture the students could not care whether he was selling Trabants, so gripped are they by his lecturing skills. A ripple of clapping breaks in the Darwin theatre - not an unusual occurrence at a Jones lecture.

Jones is a natural performer. He prowls the stage, cracking jokes and conjuring up anecdotes and powerful metaphors that serve as props to hold the students' interest, allowing them to ease their way into understanding complex subject matter.

This was an introductory lecture to a group of students beginning their degree courses in a range of subjects including biochemistry, genetics, neuroscience and human sciences. The title of the lecture was "What Sex Really Means", its aim to convey the awesome power of sex as examined under the powerful lens of modern biology (especially molecular biology) as opposed to, say, the pornographic literature of Ken Starr.

The story of sex woven by Jones criss-crossed the world of plants, animals and humans. One memorable slide showing the extraordinary lengths plants will go to to reproduce was of the "hot lips plant", which looked like pouting red lips. "Now that is clearly a come-on gesture," says Jones, adding, "the bee is a sort of flying penis."

To highlight the phenomenal disregard normal reproductive sex has for geography, Jones highlighted a Canadian study of a family with a rare inherited form of deafness. While several other families suffering the same disease were identified in Canada, one was also found in Norfolk and another indigenous one in the West Indies.

But what really gets Jones going is slugs, "utterly charming and far more interesting and if you ever step on one I think I'll cry...". With slugs being hermaphrodite, there is, Jones pointed out, a powerful temptation for them to mate with themselves - "I defy you to find a better example of inbreeding".

With a map of Europe, Jones showed how strongly asexual behaviour in slugs is affected by geography, with colder regions like Scotland (and Scandinavia) particularly prone to generating this behaviour.

He joked that in Britain, "sex stops at Preston". But there are nonetheless "hot spots" of slugs exhibiting asexual behaviour on a large scale in more southerly climes too. His passion for molluscs knows no bounds. He recalled, for instance, that many years ago he visited Thamesmead Park in south east London. "You can imagine what it was like, dog **** everywhere, empty beer cans...". But the park was home to something astonishing, a group of all female snails of the species Potamopyrgus.

He dashed off a letter to Ken Livingstone at the Greater London Council, telling him how amazing this was, suggesting the park should be renamed Potamopyrgus Park in honour of the slugs. "I got a nice letter back saying what a good idea, but then Thatcher got rid of the GLC. If we get a mayor I might try it again," he says.

At the end of the lecture, he reminded the students that the lecture was introductory and non-examinable. Which neatly explained why only one person was taking notes - and that was the journalist.