After a decade of insect migration monitoring, researchers have revealed that trillions of high-flying insects take to the skies every year to migrate.
High-flying insects are defined as insects capable of reaching over 492 feet in the air, while larger insects are categorized as weighing at least 10mg.
In a study published in the journal Science, researchers detailed that about 3.5 trillion aerial bugs fly over southern England, a movement that equates to 3,200 tons of biomass flying to and from the UK. The number of insects migrating is over seven times larger than the mass that 30 million songbirds total as they leave UK each autumn to head to Africa.
"Insect bodies are rich in nutrients and the importance of these movements is underappreciated," said study author Jason Chapman.
He also added that given the mass the insect movement represents, the migration represents the most important of the yearly animal movements that occur on land ecosystems, if densities were extrapolated to represent all airspaces above continental landmasses.
Insect Migration Patterns
The researchers were not able to record exactly where the insects were flying from and where they are headed but evidence points to a general area over UK involving the North Sea and the English Channel.
Additionally, when they examined observations on insect movement above radar sites within southern England, the researchers saw that there were differences in mass migrations depending on the season. According to their findings, insects generally head to the north during spring while they are southbound in the fall. Seasonal figures varied from year to year but overall, larger insects fly north in springtime while southward movements are observed in the fall.
Importance Of Insect Migration
According to study author Gao Hu, a lot of the insects they were able to study serve an important ecological service necessary for maintaining ecosystems healthy, like pollination, crop pests predation and providing food sources for bats and birds.
Ka Lim, also an author for the study, added that insect migration can be an important indicator regarding the state of the environment as the movement is highly sensitive to climate conditions.
"Global climatic change could cause decline of many species, but equally other highly adaptable species thrive and become agricultural crop pests," he said.
Until now, not a lot was known about the migratory activities of nocturnal insects like agricultural pests and no research has been done whatsoever to determine the numbers of migrating insects active during the day.