Big British butterflies due to climate change

Butterflies are growing along with global temperatures, a new study shows

Big Zero Report 2023

British butterflies are getting bigger and bigger, as they adapt to climate change.

That’s according to a new study by the Natural History Museum (NHM), suggesting that warming temperatures are leading to the species having to alter their size.

NHM analysed tens of thousands of species with a new computer vision technology, finding that during the last few decades, butterflies across the British countryside have been steadily growing.

The scientists from NHM and the Universities of Southampton and California, put this down to butterflies having more late-stage larvae, as temperature rises impact hatching season.

Image: The Trustees of the Natural History Museum, London

Female butterflies were also confirmed to be the larger sex of the species using the computer technology. Although this had been the presumption for a while, the study was the largest of its kind to actually test and verify this theory.

The technology used, called Mothra, was developed at the Berkley Institute for Data Science, automatically measuring the size of the specimens, length of the wings and the sex.

This study is part of a push to digitise natural history collections to make them accessible online, not only cutting emissions but also allowing easier access for people looking to learn from them.

Co-Author of the paper, Dr Phillip Fenberg from the University of Southampton, said: “Our paper is among the first to show that computer vision can be applied to these digital images for testing hypotheses on how animals may respond to climate change.

“This is accelerating our potential to understand how the biosphere will react to climate change.”

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