This article is more than 3 years old

This article is more than 3 years old

A man has been found guilty of unlawfully collecting and killing specimens of one of Britain’s rarest butterflies, the large blue.

Phillip Cullen, 57, was spotted armed with a child’s shrimping net chasing the insects at a nature reserve in Gloucestershire and was seen the next day at another prime location for the butterfly in Somerset.

When he was challenged by a volunteer at one of the reserves, Cullen claimed he was interested in parasitic wasps and orchids.

Police later raided his home in Cadbury Heath, near Bristol, and found dead, mounted butterflies in about 30 trays, including two large blues labelled with the letters CH and DB.

Prosecuting, Kevin Withey said the letters stood for Collard Hill in Somerset and Daneway Banks in Gloucestershire, the two places where Cullen had been seen. The defendant claimed CH stood for “cobalt hue” and DB for “dark blue”.

Facebook Twitter Pinterest The large blue butterfly can fetch up to £300 if it is mounted and made to look like a Victorian specimen. Photograph: Butterfly Conservation/PA

Bristol magistrates were told the large blue became extinct in the 1970s and has been reintroduced to a few sites. The panel heard there was a market for large blues, which sell for up to £300 a butterfly when they are mounted and made to look like Victorian specimens.

Cullen conceded that he traded butterflies but said he bought them from farms in Europe, set and pinned them in cases and then sold them at auction. He insisted he had not caught or killed any large blues for decades.

The lepidopterist denied capturing, killing or possessing the large blues, which are protected under conservation of habitats and species regulations, but was found guilty after a trial.

Neil Hulme, from the charity Butterfly Conservation, told the court the large blue was an “iconic species”.

He described seeing Cullen and a second man clambering over a padlocked gate at Daneway Banks, near Cirencester, in June 2015. He was carrying a child-size net. Hulme said the second man “secreted himself” under a beech tree as a lookout while Cullen “worked” a slope with his net, chasing large blues.

Asked how big a problem illegal collecting of large blues was, Hulme said: “It’s probably really a small hardcore of people. It’s not widespread but the people involved are quite determined.” Hulme said capturing just a few large blues from a site where they were doing poorly could have a huge impact.

Volunteer Mark Greaves said that he spoke to Cullen at Daneway Banks and was told he was interested in parasitic wasps and green-winged orchids.

Rosie Clegg, a volunteer large blue ranger at Collard Hill, said she had spotted Cullen there the day after his visit to Daneway Banks. He told her that he was interested in the cuckoo wasp.

In Victorian times, the large blue was a highly prized specimen because of its wonderful colour and rarity. It could not be bred in captivity and was declared extinct in the UK in the 1970s, but the determination of two scientists brought it back to life.

Jeremy Thomas, a professor of ecology at Oxford University, worked out what it needed to survive: well-grazed meadows and the presence of a particular red ant for its caterpillars to feed on.

David Simcox, a conservation consultant for the Centre for Ecology and Hydrology, drove his VW campervan to Sweden, collected some eggs from the large blues there and released caterpillars in the south-west of England.

The large blue has a remarkable lifecycle. Eggs are laid on the flower buds of wild thyme. The larvae burrow into the flower heads and, when they are about 4mm long, they drop to the ground and wait to be found by foraging red ants, attracting them with sweet secretions from a “honey” gland. The ants place them in their brood chamber and the larvae feed on ant grubs. They turn into butterflies, crawl above ground and fly from mid-June to late July.

There are 59 species of butterflies in the UK. Of these, 25 are afforded some kind of protection and six, including the large blue, are fully protected, meaning they cannot be collected, killed or sold.

Cullen will be sentenced next month.