Multiple Midsummer Butterfly Species Emerging In UK Up To A Month Ahead Of Normal Schedule In Record-Warm Spring
Midsummer butterflies are on the wing in early May after a sunny spring prompted one of the most advanced seasons for Britain’s Lepidoptera on record. The Lulworth skipper – usually found in June and July – is flying at Lulworth Cove in Dorset, the chequered skipper emerged in April rather than mid-May in Scotland and the first swallowtail, which is most common in mid-June, was spotted in Norfolk on 1 May.
“The chequered skipper is a butterfly you can set your calendar by – it typically comes out 13-15 May,” said Tom Prescott, the head of Butterfly Conservation Scotland. “I was absolutely staggered when it was seen on 26 April.”
Lepidopterists said the early appearances this year were caused by the prolonged sunny, dry spring but were also a clear sign of insects responding to global heating. While some species appear to be adapting their lifecycles to climatic changes, there are fears some early emerging insects may fall out of sync with pathogens, predators or the availability of food for their caterpillars.
“It’s fine for the chequered skipper but I worry for some butterfly and moth species that are overwintering as an egg and trying to emerge as a caterpillar in sync with the leaf flush,” said Prescott. The caterpillar of the rare dark bordered beauty moth feeds on sucking aspen but if the fine spring causes it to emerge too early there won’t be any leaves for it to eat. Many butterflies are emerging at least two or even three weeks earlier than normal this spring. The average first sighting of the swallowtail over the past 10 years has been 14 May but this year it was spotted at Norfolk Wildlife Trust’s Hickling Broad nature reserve on 1 May.
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https://www.theguardian.com/environment/2025/may/09/midsummer-butterlies-spotted-early-in-britain-after-sunny-spring