When I first heard of Hubert Duprat, I can no longer remember. But I have never forgotten his name since. Duprat is, to me, a legend – a French artist who works not with a brush, but with caddisflies. Insects that live underwater as larvae and build protective cases. From grains of sand, pebbles, shells, pine needles and aquatic plants – from whatever can be found in the streams where they live. When Duprat once read about people panning for gold in rivers, an idea took shape. Might caddisflies ever have stumbled upon gold by chance? Might they, unknowingly, have incorporated a small nugget of gleaming gold into their cases?
As an experiment, Duprat released caddisflies in the 1980s into aquaria whose floors were strewn entirely with gold flakes, diamonds, pearls and gemstones. The case-artworks that resulted are now part of prestigious collections, including that of the Centre Pompidou in Paris. These precious cases are a collaboration between the artist and the insect, or as Duprat puts it: ‘It is as much their work as it is mine.’
A few years ago, in 2018, the first caddisfly cases containing microplastics were found. It surprised me. Not so much that they were building with plastic – I was, after all, familiar with Duprat’s work – but that this should be such a recent phenomenon. Could it not be that plastic had been collected by caddisflies much earlier, and that we had simply never noticed?
As Duprat puts it: ‘It is as much their work as it is mine’
Together with biology student Isabel, I therefore spent a day delving into the collections of Naturalis. Going into the collection is a kind of journey back in time. There in the dark lie cases from long before the age of plastic, but also cases collected after the 1950s, when plastic could potentially have been gathered. And indeed. Isabel soon found a case with surprisingly yellow fragments incorporated into it, from 1971. Later, a jar full of cases with bright blue elements, from 1986. Analysis showed that the particles consisted of elements such as titanium, chlorine, sulfur, zinc and barium – precisely the elements one would expect from microplastics. It turned out that caddisflies had already been collecting plastic nearly fifty years earlier than we had thought. Decades before the term ‘microplastic’ would even be coined – which did not happen until 2004. Research into microplastics in freshwater had yet to begin at that point.
I am grateful to them, those caddisflies. Just as Duprat saw his art as a collaboration between human and insect, so I see this publication in the same way. They collected plastic particles of which humans had no inkling, and in doing so ended up, quite by chance, in the Naturalis collection. Thanks to these insects from the 1970s and 1980s, we can now say something retrospectively about microplastic pollution from that era. The discovery attracted worldwide attention, including from Nature and Science. After all those years of waiting, the flies finally shared their startling findings.
Auke-Florian Hiemstra studied biology in Leiden, conducts research into animal architecture, and is currently seeking funding for a postdoctoral position. His research can be followed on BlueSky @aukeflorian.