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April 18, 2025 report This article has been reviewed according to Science X's editorial process and policies . Editors have highlightedthe following attributes while ensuring the content's credibility: fact-checked peer-reviewed publication trusted source proofread by Bob Yirka , Phys.org A team of biologists working at the Naturalis Biodiversity Center, a research museum in the Netherlands, has found evidence of caddisfly larvae using microplastics to build their casings as far back as the 1970s.
In their study , reported in the journal Science of The Total Environment , the group discovered microplastics in larvae casings held at the museum . The caddisfly is a moth-like insect found in most countries around the world. The insect makes its home near lakes and streams, where it deposits its eggs in huge masses of jelly.
The larvae hatch a few days later and soon thereafter begin using nearby material to encase their bodies to protect against predators. In this new study, the researchers in the Netherlands found that starting more than 50 years ago, the larvae began including microplastics in their casings. The work began after one of the team members noticed something colorful in one of the larva casings held at the museum.
A close look showed it to be a particle of microplastic. That led the team to take a closer look at the 549 casings in their collection, which has been growing in number over several decades. In so doing, they found plastic in many of them.
As one example, the team found one casing that had multiple particles of blue microplastic —it was dated to 1986. Another with yellow plastic was dated to 1971. Further study of such casings also showed there was evidence of plastic additives such as lead, titanium and zinc.
The researchers suggest that microplastics have been contaminating the environment for at least the last half-century, helping to explain how so much has been found globally. They also suggest the possibility of other species being impacted for just as long. They conclude by noting that the plastics used in the casings were more visible than natural material used to build casings, and also more buoyant, factors that could potentially put the larvae at greater risk of being found and eaten by birds and fish.
More information: Auke-Florian Hiemstra et al, Half a century of caddisfly casings (Trichoptera) with microplastic from natural history collections, Science of The Total Environment (2025). DOI: 10.1016/j.
scitotenv.2025.178947 Journal information: Science of the Total Environment © 2025 Science X Network.
