Nearly 3.5 trillion migrating insects fly over south-central England annually: study

Nearly 3.5 trillion migrating insects fly over south-central England annually: study

More than three trillion migrating insects fly over the region of south-central England each year, unseen and unnoticed by humans, according to a new study by University of Exeter researchers.

Dr. Jason Chapman, an entomologist at University of Exeter and colleagues estimated that as many as 3.5 trillion bugs and butterflies migrate across the region annually. Their total mass is equivalent to nearly 20,000 flying reindeer.

While the origins of the migrating insects were not recorded, the researchers estimated that several of them were travelling to and from the United Kingdom from across the English Channel and the North Sea.

Hugh Dingle, an animal migration expert at UC Davis, said it’s just an “awfully good” research, pointing to the fact that most insect migrations have thus far remained unknown not only to the public but also to the scientists.

Speaking on the topic, Dingle said, “But perhaps because of all that attention on these big charismatic insects, the huge migrations that occur in lots and lots of other insects, all the way down to tiny aphids, is certainly not as well known by the public, and may not even be as well known by scientists.”

Over the 10-year study period, the researchers looked at bugs and butterflies flying night and day, at altitudes between 150 and 1200 meters above the ground.

The researchers reported their findings in the latest issue of the widely-acclaimed journal Science.

A report published by Discover Magazine added, "Researchers deployed a set of experiments at three locations in southern England during seasonal migrations from 2000 to 2009. They used special entomological radar devices to measure the passage of larger insects and relied on nets attached to blimps to sift out the smaller ones."

When the insects move, they take these nutrients with them, and leave them behind when they die. The researchers say that the flows of insects seem to balance out in the long run, meaning that the system stays in equilibrium, but seasonal variations do occur.

The research paper further informed...

Migrating animals have an impact on ecosystems directly via influxes of predators, prey, and competitors and indirectly by vectoring nutrients, energy, and pathogens. Although linkages between vertebrate movements and ecosystem processes have been established, the effects of mass insect “bioflows” have not been described. We quantified biomass flux over the southern United Kingdom for high-flying (>150 meters) insects and show that ~3.5 trillion insects (3200 tons of biomass) migrate above the region annually. These flows are not randomly directed in insects larger than 10 milligrams, which exploit seasonally beneficial tailwinds. Large seasonal differences in the southward versus northward transfer of biomass occur in some years, although flows were balanced over the 10-year period. Our long-term study reveals a major transport process with implications for ecosystem services, processes, and biogeochemistry.