Trillions of winged migrants take to British skies
The trillions of migrating insects weigh a combined total of 3,200 tons 鈥� the equivalent of more than 636 elephants flying overhead each year. These flying bugs offer humankind a multitude of services, scientists say.
The painted lady butterfly (Vanessa cardui), pictured, is a major component of the large day-flying insect migration studied by radar in a new study measuring migration annually over a region in south-central England, monitored with specialized radar and a balloon-supported aerial netting system. Dec. 22, 2016.
Jane Hill/Reuters
Three and a half trillion.
That鈥檚 how many insects migrate over southern Britain in one year, according to聽. To put that number in perspective, that鈥檚 the equivalent of more than 54 bugs for every person in Britain.
The team of scientists from Britain, China, and Israel spent a decade tracking insect migration at altitudes between 492 and 3,937 feet using entomological radar and an aerial insect-catching net.听
鈥淗igh-altitude aerial migration of insects is enormous,鈥� University of Exeter entomologist and co-author Jason Chapman . 鈥淭hese aerial flows are an unappreciated aspect of terrestrial ecosystems, equivalent to the oceanic movements of plankton which power the oceanic food chains.鈥�
And the vast quantity was not the only surprising aspect of their study. The researchers also discovered that insects migrate north and south seasonally (just like birds), and can reach speeds between by choosing wind patterns that are blowing in their chosen direction, Ars Technica reports.
The trillions of migrating insects weigh a combined total of 3,200 tons 鈥� the equivalent of more than 636 elephants flying overhead each year.听
But if hundreds of elephants' worth of bugs were flying overhead each year, wouldn鈥檛 we know about them already?聽
No, say scientists: the vast majority of these bugs are super small. Take the marmalade hoverfly, for example.
鈥淚t鈥檚 only about a centimeter long, it鈥檚 orange with black stripes, but it鈥檚 a hugely abundant migrant, and it actually does some very important jobs鈥� such as pollinating crops and wildflowers, Dr. Chapman .听
And the authors say Britain鈥檚 overhead migration is likely modest compared to other regions of the world. In fact, Chapman that Britain鈥檚 overhead populations are probably 鈥渃lose to minimum values鈥� because of the area鈥檚 cold and dry climate. The warm, moist skies of the Amazon 鈥� or southern California, for example 鈥� likely see far more than 3.5 trillion insects each year.
While some bug-averse people might find this study chilling, it is really quite encouraging, say scientists. Healthy insect populations are crucial for a productive environmental landscape.听
鈥淲e could not function without them,鈥� Chapman tells Reuters. The insects pollinate plants, feed birds and bats, and promote healthy soil through decomposition and other important processes.听
鈥淚f, due to human influence, a large fraction of the [insect] migrant population is wiped out, it might have catastrophic consequences for those particular ecosystems,鈥� Eric Warrant, a zoologist at Lund University in Sweden, told Science magazine in a聽.听聽
This study proves that insect migrations are too understudied, and that is the real misfortune, say scientists.
鈥淐ertain insects like locusts and the monarch butterfly, have gotten a great deal of attention,鈥� Hugh Dingle, an expert on animal migration at the University of California, Davis, told NPR. 鈥淏ut 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, are certainly not as well known by the public, and may not even be as well known by scientists.鈥澛犅�