About 3.5 trillion insects migrate over the skies of southern England every year, according to researchers. These insects have a total mass of up to 3,200 tons, which is equivalent of an herd of 800 huge elephants.
The study was led by researchers from the University of Exeter and Rothamsted Research. Jason Chapman, one of the authors of the study and an entomologist at the University of Exeter in Cornwall, said that he believes the numbers in the southern U.K. are close to minimum values for the rest of the world. He further said that almost anywhere he can think of will likely have much higher values, especially in the hotter parts of the world.
Dr. Chapman added that the insect bodies are rich in nutrients and the importance of these movements is underappreciated. He also said that if the densities observed over the southern U.K. are extrapolated to the airspace above all continental landmasses, high-altitude insect migration represents the most important annual movement in ecosystems on land, comparable to the most significant oceanic migrations, as noted by Phys.org.
In the study, the researchers used a special entomological radar that could determine body mass, flight altitude and other information about individual insect with a mass of 10 milligrams or more. This is about the size of a housefly and bigger. They found that all the insects were flying at least 500 feet off the ground. To gauge the number of smaller insects, the team used aerial netting to monitor the tiniest migrators, according to LA Times.
The results showed that 99 percent of the insects that migrated belong in the smallest group of insects, which is about smaller than a housefly in size. These are made up of only 80 percent of the total migrating biomass. Meanwhile, the 15 billion medium-sized insects and 1.5 billion large insects were about 12 percent and 7 percent of the mass, respectively.
They also discovered that 70 percent of that biomass movement from migration happened in the daytime and that the migration was northward in the spring and southward in fall. The team said that the bodies of insect are composed of 10 percent nitrogen and 1 percent phosphorus by dry weight. These mean that they are rich sources of nutrients that could be needed for plant productivity.