If a bug starts its life in water, there’s a good chance it is eating microplastic pieces.
Mosquitoes start their lives as larvae, living in the water. They are filter-feeders, wafting tiny pieces of algae into their mouths in order to grow and move on to the non-feeding pupa stage. After that, they hatch and fly away as adult mosquitoes.
What scientists have learned recently, and published in a study for the journal Biology Letters, is that a great number of mosquitoes ingest microplastic beads in the larval stage and these pieces remain in their body, even through adulthood. The larvae are unable to distinguish between algae and microplastic pieces, as they are roughly the same size; and because of the way in which their bodies develop, there is no mechanism to dispose of the plastic before hatching.
The discovery has been surprising to many. As lead study author Prof. Amanda Callaghan from the University of Reading said,
“It is a shocking reality that plastic is contaminating almost every corner of the environment and its ecosystems. Much recent attention has been given to the plastics polluting our oceans, but this research reveals it is also in our skies.”
It is likely that other flying insects that start out as water-based larvae are also carrying microplastics into the air. The plastic pieces would be passed on to predators who feed on those insects, such as spiders, dragonflies, birds, and bats. Callaghan again: “This is a new pathway to get plastics up in the air and expose animals that are not normally exposed. We don’t know what the impact will be.”
It is disconcerting to learn of more pathways for contamination, but it shouldn’t be surprising. The problem is that very little research has been done into microplastic’s effect on freshwater habitats; most attention to date has been given to ocean pollution and plastic accumulation in marine animals and sea birds. It’s time we turned our attention to freshwater sources, as well.
From the Guardian:
“It is widely accepted that humans are also consuming microplastics. ‘We all eat them, there’s no doubt about it,’ said Callaghan. Eating seafood such as mussels or cod is one route, while beer, sugar and sea salt have all been found to contain microplastics. Exposure is likely to rise, as plastic production is expected to climb by 40% in the next decade, prompting scientists to call for urgent research on the effects of microplastics on people.”
It’s hard to know what to do. A ‘Save the mosquitoes!’ campaign isn’t going to catch on, but knowing what they carry in their bodies may spur people to greater action. It is indicative of a problem that’s deeper-rooted than we may have realized. With plastic floating in our drinking water, piling up in the ground, and now flying above our heads, it is more important than ever to cut back on personal consumption of plastic products (especially single-use disposables), ask local businesses to do the same, pressure food manufacturers to take responsibility for the full life cycle of their packaging, and ask governments to take anti-plastic action at a national level.