An extremely rare half-male, half-female butterfly has emerged from its chrysalis at Butterfly World in St Albans and now staff are calling on the public to vote on a dual-gender name for the Great Mormon Butterfly.

An extremely rare half-male, half-female butterfly has emerged from its chrysalis at Butterfly World in St Albans and now staff are calling on the public to vote on a dual-gender name for the Great Mormon Butterfly.

Late on Tuesday (20), lepidopterist Louise Hawkins noticed the distinctive, “breath-taking” dual-gender markings on the butterfly. She said: “We had one three or four years ago. But I didn’t expect another one to be born here so soon after. When we had the first one, I thought it was a once in a lifetime thing.”

The genetic mutation, called gynandromorphism, is thought to only occur once in every 10,000 butterflies - or in 0.01 per cent. The as-yet-unnamed butterfly looks like two seprate and distinct butterflies in one, with a straight dividing line through it’s abdomen.

Louise said: “In its very early stages the sexes fail to develop properly. It’s generally understood that they have a shorter life-span. Sometimes they can have problems feeding.”

Louise told the Herts Ad the males and females of some species of butterflies are so similar that it’s often difficult to tell, but said with that “the Great Mormon butterfly, the sexes are just so different. It’s an amazing thing to see. It’s such a phenomnial thing to have one here.”

She added that it is being kept in a large mesh cage and is staying very still because of the inclemant weather.

Please cast your vote on what to name the butterfly and head down to Butterfly World Project in Chiswell Green to see this rare sight for yourself.

Voting ends at 5pm today (23).