It seems miraculous that any butterflies can survive a month of rain, but as soon as the autumn sun emerges so do red admirals and the occasional painted lady, en route for the sunnier south.
The 59 British species are perfectly adapted for our weather but adjusting to rapid climate change is more challenging, as two new studies led by scientists from the University of York show.
Relatively cool regions should gain more warmth-loving butterflies than they lose but many species are not moving north as widely or quickly as expected.
One reason is some species are isolated on fragments of suitable habitat, unable to expand through a human-dominated landscape. Climate change has helped the versatile comma spread from Yorkshire to Aberdeen in two decades. But the silver-studded blue, which requires heathland or grassland, has been unable to move between these rare habitats and expand its range.
Another reason is butterflies and moths are emerging in spring on average between one and six days earlier per decade. Flexible species with multiple breeding cycles, such as the speckled wood, benefit from “more” time. But single-generation specialists, such as the endangered high brown fritillary, are thrown out of sync with the plants they feed on.
