MALE ladybirds are pretty stupid. They can spend up to four hours mating with a dead female before realising something is wrong. And if these cold-blooded creatures get caught in the act when the Sun goes down, the falling temperatures may leave them immobilised till morning. Such tales about one of the world’s most cherished insects might scandalise ladybird lovers. Yet they come from an ardent admirer who should know. Michael Majerus, a naturalist at the University of Cambridge, is the founder and coordinator of the Cambridge Ladybird Survey, an extraordinary study of the activities of ladybirds in Britain.

The survey started in 1984 as a casual request to amateur entomologists for more information on ladybirds to assist his research on sexual selection. From that, says Majerus, it developed “more by luck than judgment” into one of the most exhaustive nature-watch campaigns ever, drawing in a diverse network of part-time ladybird spotters. Participants ranged from professional entomologists to primary schoolchildren, who all recorded their observations and sent them to Majerus and his small team of researchers and collators in the university’s genetics department.

As the survey’s network of recorders quickly grew to an estimated 30 000 people, so the information poured in. “There’s so much data you can’t believe it,” says Majerus. And much is valuable scientific information too, he insists. On the strength of the survey’s results, Majerus and his colleagues have produced several academic papers, which are all “quite widely cited”, and there are more in the pipeline, he adds.

The Cambridge survey soon overshadowed Britain’s official project, the Coccinellidae Distribution Mapping Scheme, which had been running since …