A cold and wet summer has led to a tough autumn for butterflies – and gardeners are being asked if they can help.

Dorset-based charity Butterfly Conservation is asking people to take part in a survey to help find out how late in the year butterflies can still be seen.

The experts said butterfly numbers fell during August but the warm conditions in spring enabled many species to emerge and breed early this year.

These good spring and early summer conditions enabled more butterflies to fit in an extra generation, so we may be poised for an impressive autumnal emergence of species such as Comma, Red Admiral and Speckled Wood in the coming weeks.

Despite their association with summer, Peacock, Small Tortoiseshell, Large White, Small White, Painted Lady, Small Copper, Common Blue and other butterfly species can be seen into early November if mild conditions persist.

A warm spell of weather this month could provide a timely boost to garden sightings as butterflies fly in to take advantage of the abundant blooms in garden borders while most flowers in the countryside have gone over.

Butterfly Conservation head of recording Richard Fox said: “Gardens become increasingly important for butterflies at this time of year.

“Nectar, the flight fuel for most of our butterflies, is in short supply in the countryside as we move into autumn, yet many of our garden flowerbeds and borders are still full of colour.

“For some butterflies it is a matter of life and death; species such as the Small Tortoiseshell, Peacock and Comma, which hibernate as adult butterflies, have to feed up and lay down substantial fat reserves in their bodies in order to survive the winter. If they can’t find enough nectar they simply won’t make it through to breed next spring.

“Others, such as the Painted Lady and Red Admiral will be taking on fuel reserves that they need to migrate south to warmer climes around the Mediterranean.”

The aim of the Garden Butterfly Survey is to assess the changing fortunes of butterflies in gardens and, ultimately, to understand how important gardens are for our butterfly populations and what gardeners can do to help. 

Butterfly sightings can be entered online at www.gardenbutterflysurvey.org to help build a picture of the fortunes of these beautiful insects.