The decline of butterfly collecting as a hobby is making conservation research more difficult for entomologists, according to an analysis of 1.4 million specimens held in US museum collections dating from the 1800s.
Although butterfly collecting is often seen as a pastime of Victorian-era gentlemen, Erica Fischer at King鈥檚 College London and their colleagues actually found that the largest growth in specimens occurred between 1945 and 1960, showing an 82 per cent increase.
This may have been driven by college-educated veterans who received free tuition after the second world war, the researchers say. The number of specimens collected in the US then faltered in the 1960s, and plunged after 1990, the team found.
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Fischer says that instead of collecting physical specimens, amateurs these days are more likely to gather observational data, particularly photos posted to online databases. While useful, photos don鈥檛 let researchers analyse DNA, chemical ratios, internal organs or the pollen found clinging to specimens, says Fischer.
For example, Heidi MacLean at Aarhus University in Denmark and her colleagues, in a study published in 2018, examined physical specimens of the Mead鈥檚 sulphur butterfly (Colias meadii) collected over the course of 60 years at Loveland Pass, Colorado, to see how they adapted to climate change by changing colour. 鈥淲e couldn鈥檛 have done it without the actual specimens,鈥� says MacLean. 鈥淓ven though we used image analysis, the lighting and the background had to be the same for every specimen.鈥�
Fischer is now studying collections of butterflies and moths in UK museums to see if the same decline holds true and the cultural forces behind the change. 鈥淚s it that science has moved away from collections? Is it the professionalisation of science?鈥� says Fischer.
To solve the looming shortage of butterfly specimens, Fischer says scientists can lean on iNaturalist images 鈥� not directly for research, but to ask the photographer to collect a specimen for research purposes, where this is possible and legal.
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