Mosquitoes Can Contaminate Ecosystems with Tiny Pieces of Plastic | Science

The mosquito larvae are remarkably unattractive. They glide through the ponds and puddles in which they live, creating currents that draw tiny particles of food into their mouths, but tiny pieces of plastic can also easily slide down the hatch. New research shows that these "microplastics" remain in the belly of mosquitoes even after they have emerged from the water as flying adults, putting their terrestrial predators at risk of ingesting contaminants.

To conduct the study, the researchers poured small fluorescent yellow and green plastic balls the size of red blood cells into cups filled with water containing hungry mosquito larvae. Several days later, they fished the larvae.

When the larvae grew up, the team spotted bright pearls inside their squamous tubules – structures equivalent to those of the kidneys – confirming that microplastics can persist in the body of an insect as it passes from larval stage in the adult stage. The researchers also found that the smaller the pearls, the more likely they were to become mosquitoes.

The results, reported today in Letters of biology, indicate that, once the adult mosquitoes have abandoned the water (as shown in the picture above), they can introduce the plastic pieces that they have eaten as larvae in their new ones habitats. This means that when non-aquatic predators – including birds, bats and dragonflies – nibble on mosquitoes, they risk receiving an unhealthy dose of microplastics from the polluted waters in which their prey is born. Scientists already know that microplastics can be toxic to many underwater animals. This new transportation route could also pose a threat to species that eat insects on land.