The UK experienced a significant surge in butterfly populations this summer, driven by a series of record-breaking heatwaves, according to the latest results from the Big Butterfly Count. This annual event, recognized as the world’s largest insect survey, involved more than 100,000 volunteers who recorded nearly 1.4 million butterflies and day-flying moths across the country.

The survey results indicate that this year delivered the second-best butterfly season in 16 years, with unusually high temperatures providing favorable conditions for adult butterflies to thrive, reproduce, and expand their presence in both urban gardens and rural areas. The Dorset-based wildlife charity responsible for the count attributed the population boom directly to the warm weather, which featured five distinct heatwaves throughout the summer.

Among the species benefiting from the heat was the painted lady butterfly, a migratory insect that embarks on a complex, multi-generational journey from sub-Saharan Africa to the UK each year. The count showed a remarkable 335 percent increase in painted lady numbers compared to the previous year, representing the second-highest tally for this species since the survey’s inception in 2010.

The results highlight the broader impact of climate patterns on butterfly populations in the UK, with warmer temperatures enabling a greater number of individuals to reach maturity and complete their life cycles. While this boom is seen as a positive development for butterfly enthusiasts and conservationists, it also underscores the sensitivity of insect populations to changing environmental conditions.