Appeal launched to help rare Large Blue butterfly found on Charlton Mackrell nature reserve

Somerset Wildlife Trust has launched a new appeal which will help to support the Large Blue butterfly.

The Large Blue Butterfly Appeal has been launched to help this rare and iconic butterfly, which was declared extinct in the UK in 1979.

Thanks to donated eggs from Sweden it was reintroduced to South West sites in the 1980s - the trust's Green Down Nature Reserve at Charlton Mackrell being one - which is now home to the UK's largest population of Large Blue butterflies.

Their future, however, is under threat once more due to the increasingly unpredictable weather due to our changing climate.

The drought in 2018 meant fewer red ant grubs and less wild thyme, the Large Blue caterpillar's food plant, resulting in a steep fall in numbers in 2019 – from approximately 9,500 adults in 2018 down to only 3,800.

This spring's cold snap will likely affect the Large Blue too, though it will be 2022 before we know the full impact.

The appeal is raising funds to support important monitoring of populations at Green Down, and to carry out habitat work to provide the conditions that this rare butterfly – and the species it relies upon to complete its complex lifecycle – needs.

This includes controlling tree and scrub growth, carrying out conservation grazing, and fence and infrastructure repairs.

The appeal's ambition is to help build the population sufficiently, so the Large Blue butterfly can withstand climate shock and can also naturally colonise, or be introduced to, other nearby nature reserves in the Polden Hills.

Mark Green, the trust's reserves manager for South Somerset, said: "The story of the Large Blue butterfly is a fascinating one and an incredible conservation success story here in Somerset.

"But while our Green Down reserve has proved to be a safe haven for this wonderful creature so far, it is going to take a great deal of effort to ensure that the habitats they rely on for their fragile lifecycle are resilient enough to cope with now unpredictable weather conditions.

"Monitoring is critical, but with support we can work to grow its population. We hope people get behind the appeal and help ensure the Large Blue has a future here in the county."

An amazing lifecycle

The Large Blue butterfly exists parasitically with a tiny red ant – Myrmica sabuleti – which is deceived into taking the butterfly's caterpillar into its brood chamber, where the caterpillar feeds on ant grubs before pupating and emerging as a beautiful butterfly the following year.

With such a niche lifecycle, as well as the butterfly historically being a target for collectors, and having been negatively affected by changing agricultural practices, it's no wonder that Large Blue's populations have always been fragile.

In addition to the Large Blue butterfly, the Large Blue Appeal will also benefit other species in the area, including the Shrill Carder Bee, one of the UK's rarest bumblebees; cut-leaved selfheal, a perennial herb now only found in a few scattered locations in southern England; and the lesser whitethroat, a shy summer migrant that lives in the dense hawthorns and blackthorns around the edge of the Green Down reserve.

These species also rely on the conservation work the trust does on its Green Down reserve for their survival too.

You can donate to the appeal by visiting https://www.somersetwildlife.org/largeblueappeal, by telephoning 01823 652429 and speaking to Zoë, or by sending a cheque made payable to Somerset Wildlife Trust to 34 Wellington Road, Taunton, Somerset, TA1 5AW. Please specify that your cheque is for Large Blue Appeal.