Fleas are an irritation for many people, but for Robert George they are a passion. For the past 58 years he has compiled detailed records of the blood-sucking parasites to create an atlas of fleas.

“It's kept me out of mischief,” Mr George, 86, said. “They intrigue me. I've always been able to find a lot of time for fleas.”

He has counted and identified fleas in samples sent to him by other researchers, on the bodies of animals, in their nests and, for bats, in their faeces to get an accurate idea of how they are spread across the British Isles.

People are bitten most frequently by the human flea, Pulex irritans, but our blood is also a favourite of the cat and hen fleas. Others that like to take a bite out of people include the hedgehog flea and the grey squirrel flea.

Hedgehogs, squirrels and house martins are the most flea-ridden animals in Britain and Ireland — one hedgehog alone was found to have 7,116 fleas on it — and bank voles are a home to more species of flea than any other animal (at least 27).

Moles are afflicted with the biggest specimens in Britain: the mole flea, Hystrichopsylla talpae talpae, growing up to 7mm long, though a dwarf in comparison with fleas in Russia and North America, which reach 25mm.

Mr George, of Bournemouth, is a retired teacher and wartime fighter pilot, whose book Atlas of the Fleas (Siphonaptera) of Britain and Ireland is published this week. “I'm the only person in the country now who is doing fleas seriously and I'm often called the Flea Man,” he said. “I am frequently asked why I work on 'those horrible, dirty things'.”

His fascination with fleas began in 1949, when he was living close to a butcher's and restaurant in Gloucester and trapped 35 mice over three nights.

He collected 15 fleas from one mouse and sent them to Frans Smit, curator of the Rothschild Collection of Siphonaptera at Tring, Hertfordshire. Mr Smit told him that they included two species that had never been recorded in Gloucestershire before.

Mr George, who studied beetles at the time, quickly changed allegiances. “The temptation of adding new knowledge on the British fauna was too great. Fleas had one great advantage over beetles — there was little competition,” he said.

His atlas, published by the Biological Records Centre, highlights the most successful species of flea, including cat, mole and vole fleas, as well as those in decline. “Dog fleas have become very rare. Nearly all fleas on dogs now are in fact cat fleas.”

Helen Roy, of the Centre for Ecology and Hydrology, who edited the atlas, said that such studies helped scientists to assess biodiversity in Britain.

“We need high-quality detail and we can't do it without volunteers like Mr George,” she said. “He makes the subject of fleas absorbing.”

BITING WITS

— For the poet John Donne, fleas became a metaphor for would-be seducers. In The Flea he used the insect as a device to persuade a woman that to sleep with a man was a matter of little consequence

— Jonathan Swift's reference to fleas is one of his most famous quotes. In A Rhapsody he wrote:

“So, naturalists observe, a flea

Hath smaller fleas on him that prey

And these hath smaller fleas to bite 'em

And so proceed ad infinitum”

— Ogden Nash, the 20th-century American writer, was much briefer in his poem Fleas, which went simply: “Adam Had'em”

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