We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Wrapped up in plastic
Summary
Researchers discovered that caddisfly larvae in a Swiss stream had begun incorporating plastic waste fragments into the protective cases they normally build from sand and plant material. This behavior shows how plastic pollution is altering the behavior of aquatic insects and potentially affecting the quality of the protective structures they rely on.
Plastic is a versatile material appreciated for its durability and wide applicability in everyday products like food containers, beverage bottles, and medical devices. However, mismanaged plastic waste frequently washes into streams and rivers, where it is consumed by various organisms. To help avoid mortality from potentially crushing predators such as juvenile dragonflies (Odonata) and brown trout (Salmo trutta), the aquatic larvae of caddisflies (Trichoptera) build protective cases. Interestingly, we recently discovered that caddisfly (Lepidostoma basale) larvae use plastic waste as a material for case-building (Aquat Biol 2019; doi.org/10.3354/ab00711). During a laboratory experiment, the caddisfly larva shown here was offered blue microplastic particles (<5 mm) of polyethylene terephthalate (PET, a plastic type commonly used in beverage bottles), along with gray sand grains. After having been removed from its original case composed of natural materials, the larva immediately started building a new case using the PET particles, and then later incorporated the sand grains into its case. The experiment revealed that caddisfly case stability decreased with increasing PET particle load (Environ Sci Pollut R 2020; doi.org/10.1007/s11356-020-08790-5), suggesting that plastic waste incorporation in caddisfly cases may reduce protection from predators and, thereby, influence predator–prey interactions. Fish often consume caddisfly larvae along with their cases, and microplastics are known to cause inflammatory responses in fish. The question that remains unanswered is how microplastics in caddisfly larval cases may affect predatory fish.
Sign in to start a discussion.
More Papers Like This
Caddisfly Larvae are a Driver of Plastic Litter Breakdown and Microplastic Formation in Freshwater Environments
Researchers found that freshwater caddisfly larvae actively incorporate polylactic acid plastic film into their protective cases and rapidly fragment it into hundreds of microplastic particles, representing a previously unrecognized biological mechanism of microplastic formation in freshwater ecosystems.
Microplastics of different characteristics are incorporated into the larval cases of the freshwater caddisfly Lepidostoma basale
Researchers found that the freshwater caddisfly larva Lepidostoma basale actively incorporated microplastics of various sizes, shapes, and polymer types into its larval case alongside natural materials, representing a novel pathway of microplastic interaction beyond dietary ingestion in aquatic insects.
A curious case: caddisfly cases built from brick and sewage overflow microplastics
Researchers collected over 1,100 caddisfly cases from three locations in the Netherlands with varying levels of urbanization and sewage overflow pollution. In the most polluted stream, more than half of all cases contained artificial materials including microplastics from sewage overflows and brick fragments from urban areas. This is the first study directly linking sewage overflow events to microplastic incorporation in caddisfly cases, raising concerns about plastic transfer through aquatic food webs.
High Density of Microplastics in the Caddisfly Larvae Cases
High densities of microplastics were found embedded in the cases (shelters built from environmental debris) of caddisfly larvae, with plastics replacing natural materials like sand grains and plant fragments. This documents how widespread microplastic contamination has become in freshwater insect habitats and raises concerns about its effects on larval development.
PVC and PET microplastics in caddisfly (Lepidostoma basale) cases reduce case stability
Caddisfly larvae (Lepidostoma basale) incorporated PVC and PET microplastics into their protective cases in the laboratory, and increasing plastic content made the cases less structurally stable than cases built from sand. Weaker cases could impair the larvae's protection from predators and their ability to resist stream currents.