Researchers from the University of Reading are suggesting that microplastics - tiny shards of plastic from man-made products - are being passed up the food chain through an avenue other than marine life.

It is generally accepted that the often difficult-to-see and thus hard-to-collect microplastics overwhelm the world’s oceans, harming marine life and subsequently threatening human health. However, the team from Reading believes the microplastics are also entering the food chain through mosquito larvae and other flying insects.

The team found that mosquito larvae, in particular, feasted on microplastic beads, the kind commonly found in cosmetics. Following the insects through their life cycle, researchers determined that as the plastic transferred into the adult form of mosquitoes, whatever ate the mosquitoes would inevitably ingest the plastic as well.

"The significance is that this is quite possibly widespread," said Amanda Callaghan, biological scientist at Reading and lead study author.

"We were just looking at mosquitoes as an example but there are lots of insects that live in water and have the same life-cycle with larvae that eat things in water and then emerge as adults."

The animals likely to eat insects such as mosquitoes include several bird varieties, spiders and bats - all of which are a food source for other animals.

"It's basically another pathway for pollution that hadn't been considered previously," Callaghan said.

Despite recent efforts to limit single-use plastics, the team warns that the issue may be much more concerning.

"It's a major problem and those plastics already in the environment are going to be with us for a very, very long time," Callaghan said.

The study is published in Biology Letters.

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