Scientists fear early emerging insects may fall out of sync with pathogens, predators or availability of food

Midsummer butterflies are on the wing in early May after a sunny spring prompted one of the most advanced seasons for Britain’s Lepidoptera on record.

The Lulworth skipper – usually found in June and July – is flying at Lulworth Cove in Dorset, the chequered skipper emerged in April rather than mid-May in Scotland and the first swallowtail, which is most common in mid-June, was spotted in Norfolk on 1 May.