The return of this star butterfly species is a welcome success story
THE STATE OF BUTTERFLIES IN THE UK IS a story in two parts. On the one hand, surveys by Butterfly Conservation show that a whopping 80 per cent of butterfly species have become scarcer or decreased in range since the 1970s. But on the other, a handful of species have bucked the trend, including some helped by a warming climate and others by intensely targeted conservation work.
Among them is the large blue, star of BBC series Wild Isles (Grasslands episode), which was declared extinct in Britain in 1979 but has prospered at a few carefully managed sites in south-west England since its reintroduction four years later.
It is on the wing in mid-June and has a strange lifecycle involving ants. The caterpillar releases a pheromone that certain red ants can’t resist, enticing them to take it underground into their nest, where the parasite feasts on ant grubs and completes its development.
Wild Isles large blue butterflies feature in episode three