Migrating flies vital for people and nature - University of Exeter

Buzzing insects may be seen as pests – but globally, hundreds of fly species migrate over long distances, with major benefits for people and nature, new research shows.

Bugs such as houseflies, fruitflies, blowflies, hoverflies and mosquitoes all belong to an order called Diptera – which contains over 125,000 known species, and possibly over a million in total.

The new study finds that almost 600 of these species are likely to be migratory – and the true number is probably far higher.

This is important because these insects play multiple important roles, including as pollinators, pest controllers and decomposers.

With insect numbers declining worldwide, the review highlights the need for complex, connected habitats to support flies along their epic journeys.

“Migrating flies play an unparalleled range of ecological roles – making them a major force in ecosystems and the economy,” said Dr Will Hawkes, from the Centre of Ecology and Conservation on Exeter’s Penryn Campus in Cornwall. “Many of the species that benefit humans are under threat from climate change and other human impacts – and many could disappear without ever being documented unless action is taken. To conserve them, it will not be enough to protect or restore habitat at single locations; the entire migratory route must be capable of sustaining these insects.”

Dr Karl Wotton said the priority should improving “connectivity” – linking insect-friendly areas across landscapes.

“Worldwide, factors including urbanisation, intensive agriculture and destruction of wetlands have made large areas unfriendly to insects – potentially creating damaging gaps on insect migration routes,” Dr Wotton said.