Why is a ladybird called a ‘bishy barnabee’?

People in different regions like to think their dialects incomprehensible to outsiders, yet they can usually come up with quite a short list of words that differ from the norm. In Norfolk a favourite is bishy barnabee for ‘ladybird’. Ladybird, as I have mentioned before, refers to Our Lady, the Virgin Mary. But there have been attempts recently to derive bishy barnabee from Bishop Bonner (1500-69). Professor Peter Trudgill, who, as a sociolinguist born in Norwich, should have known better, wrote in an OED blog that bishybarnybee ‘comes from Bishop Bonner’s bee. Bishop Edmund “Bloody” Bonner, who had been vicar in the Norfolk town of East Dereham, became bishop of London in 1539 and was known as a ferocious persecutor of Protestant martyrs during the reign of Queen Mary.’