An ichneumon wasp new to the UK was caught in a chance sweep of a butterfly net at the RSPB’s Broadwater Warren nature reserve is a type of wasp never before recorded in the UK.
Back in 2013, Tony Davis of Butterfly Conservation was undertaking a moth monitoring programme at Broadwater Warren when he came across an ichneumon wasp specimen; a parasitic wasp, Lymantrichneumon disparis, now known to be a genus and species new to Britain.
Tony said: ‘I’d finished my work and was leaving the reserve but couldn’t resist one last sweep on my net and that’s when I found the wasp. I knew it was something special, but I could never have guessed it was an entirely new species to the country‘.”
Dr Gavin Broad is an expert on ichneumonid wasps at the Natural History Museum. The specimen was sent to him for identification and he believes the find was a recent colonist from continental Europe. He said: ‘It’s not uncommon to find parasitic wasps new to Britain, but to find a new genus for the country that is large and showy is very unusual and good evidence of change in our fauna. I knew almost immediately what this wasp was as I’d recently been looking at some Japanese specimens of Lymantrichneumon disparis. It was rather surprising to see one from Britain!‘.
In Europe the wasp parasitises a few related moth species including the gypsy moth, which has recently colonised parts of southern England. It is possible that the arrival of the wasp is related to this gypsy moth colonisation. However, the wasps are known to parasitise native moths too, so its arrival could also be due to warming of the climate.
Broadwater Warren was acquired by the RSPB in 2007, when work started to remove ranks of conifers to restore the historically open landscape of the Weald and improve the surrounding woodland for wildlife. Almost 80 per cent of the UK’s heathland has disappeared since the 1800s due to forestry, agriculture and urban development.