British swallowtail split from European cousins much earlier than thought, study finds | Butterflies

endangered swallowtail butterfly Papilio machaon britannicusBreeding regularly only in Britain, on the Norfolk Broads, this species has been a separate subspecies for at least 200,000 years, according to one study.

It is smaller, darker in color, and much rarer than the continental swallowtail. English It was previously thought to have developed its distinctive form during its confinement in the wetlands of eastern England over the last 8,000 years, after Doggerland was flooded.

But new genetic study shows English It is a wetland specialist and may have once occurred much more widely in northern European wetlands, diverging from its continental cousins ​​between 200,000 and 1.7 million years ago.

Whole genome sequencing of swallowtail populations across Europe. Conservation and Diversity of Insectsfound some evidence of consanguineous marriage English but concluded that their surviving populations did not suffer from deleterious mutations.

The study is likely to transform conservation approaches to swallowtails in Britain. Some butterfly experts discussed recently continental swallowtail, Papilio machaon gorganusThis much more common species, as its caterpillars feed on a variety of plants including fennel and parsnips, could be introduced to Britain and become much more widespread, potentially hybridising “less successful” ones. English outside of your existence.

But its chairman, Mark Collins Swallowtail and Birdwing Butterfly Trust and one of the paper’s co-authors, genetic difference English making it worthy of a renewed conservation effort. Britannicus It is found nowhere else in Europe and is in danger of extinction as global warming causes sea levels to rise, threatening freshwater wetland habitats.

“We’re looking at not only a British relict population in the Norfolk Broads, but also a relict population that was once much more widely distributed in European wetlands,” Collins said. “Britannicus “It is protected by law for good reason because it is part of our own natural heritage, something unique, and we must not allow it to disappear.”

Caterpillars in the wild English It will only reliably eat milk parsley, a rare wetland plant, which is why the butterfly is so rare in Britain.

Both plants and butterflies are threatened by rising seas causing the salinization of the Norfolk Broads, England’s largest freshwater wetland. With most of Britain’s breeding populations living at or below sea level and salt water rapidly killing milkweed, the species will need to be relocated to new wetlands protected from rising seas in the long term.

Meanwhile, global warming is ensuring continental swallowtail reaches Britain more regularly. It is regularly seen in Kent and Sussex and often breeds successfully in these counties during the fine summer months.

While some lepidopterists believe it is inevitable that continental subspecies will eventually come together English Collins said he eliminated it by hybridizing English They can survive in wetlands if given a helping hand.

“Special wetland subspecies have a very good chance of surviving into the future, along with generalist swallowtail species, gorganusflies over the wider rural area,” he said. “Mybridization may occur on the coasts, but English Our wetlands can endure if we protect them.

“We now know that we are faced with a distinctive butterfly that needs to be protected. We urgently need to identify the best places to make sure we can grow milk parsley there and introduce the butterfly so it will thrive. Lakenheath in Suffolk, Shapwick in Somerset or on sites in Yorkshire. “This is a project that is our target.”

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