Holly blue butterfly makes a comeback

A species of butterfly that is targeted by a parasitic wasp which kills its caterpillars by laying eggs inside them has enjoyed a surprisingly good year despite the wet July and August.

The holly blue butterfly, a garden favourite, saw a 151 per cent increase in numbers compared to last year and its best showing in the Big Butterfly Count since 2010, after a series of steep declines.

When numbers of both species are low, the holly blue can quickly build its population but the wasp soon catches up to take advantage of the booming numbers of caterpillars and the butterfly’s population crashes.

As a whole, however, fewer butterflies were spotted on average than in 2014, charity Butterfly Conservation said.