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UK's Unique Swallowtail Butterfly: A 200,000-Year-Old Relic
5 Jul
Summary
- Britain's unique swallowtail butterfly subspecies is 200,000 years old.
- Rising sea levels and habitat salination threaten its survival.
- A new study supports renewed conservation for the distinct subspecies.
The endangered swallowtail butterfly subspecies, Papilio machaon britannicus, found predominantly in Britain's Norfolk Broads, has been revealed as a distinct lineage for at least 200,000 years. This finding, based on whole-genome sequencing, suggests it originated from a wider European wetland distribution rather than a recent isolation.
This unique British subspecies, smaller and darker than its continental relatives, is critically threatened by global heating. Rising sea levels are causing increased salination of its essential freshwater wetland habitats, jeopardizing the milk parsley plant that its caterpillars exclusively consume.
Conservationists are now calling for a renewed focus on protecting britannicus, emphasizing its unique genetic identity and status as a relict population. The study's findings bolster arguments against introducing the more common continental swallowtail, which could hybridize and potentially eliminate the rarer native subspecies.
Urgent conservation actions are planned, including identifying and preparing new wetland sites to cultivate milk parsley and reintroduce the butterfly. These efforts aim to safeguard britannicus from extinction as its current habitat faces irreversible changes due to rising sea levels.
