Butterflies are good bellwethers for our increasingly weird climate and its impact on insect life because they are so visible. Autumn last year brought the first sighting of an American painted lady in Cornwall since 1876. And this autumn there were almost certainly the first British-born American painted ladies, after this extremely rare migrant set up home on the Isles of Scilly.
The butterfly is native to the US, and other US natives have been blown across the Atlantic this warm, windy autumn, including the green darner dragonfly. The American painted lady is also resident on the Canary Islands, and this is the likely source of most British individuals.
A steady smattering of sightings on St Mary’s in October culminated in five being spotted in a single field, almost certainly the Scillonian offspring of a gravid female.
Painted ladies are natural migrants, adapted to breed quickly and move on, transitioning from egg to adult butterfly in only six weeks. On the Isles of Scilly, larvae probably fed on Jersey cudweed, itself once extremely rare but now popping up as a “pavement weed” across Britain.
As a fascinating new book on rare British migratory butterflies by Peter Eeles reveals, there is a long history of unexpected arrivals on our shores. But hummingbird hawkmoths feeding on valerian in November and large white caterpillars still munching kale in my Norfolk garden is definitely not normal!
