Running for the hills

Around the world, insect species are responding to the climate crisis by shifting their habitats northwards and upwards, but this could have potentially catastrophic results for our ecosystems

- Gary Hartley

In the Alps and Apennines of southern Europe, nearly all the longhorn beetles are moving uphill, and way up at the peaks, the isolation of a brown butterfly with orange-tipped wings is pushing it towards extinction. This is a snapshot of a global trend. With temperatures rising and pressure on biodiversity growing, insects vital to our ecosystems are not only moving north and south, but up.

Research shows many animals are making similar moves, but insects' high levels of mobility and short generation times allow them to respond quickly to change. Bumblebees in the Pyrenees have moved upwards on average by more than a metre a year, with some species making significantly greater journeys. Moths on Borneo's Mount Kinabalu have followed suit.

All of this makes them a useful indicator of the speed of climate change and ecological impacts at higher altitudes - often global biodiversity hotspots and havens for endemic species. To try to grasp the implications, scientists are filling their backpacks and lacing up their walking boots.

"If you want to track climate change on a mountain, you go a few metres. To do that with latitude, but on a flat basis, you have to move many kilometres," said Prof Jane Hill from York University.

Studies also show that reproduction and development can be hit as insects move upwards. For species long adapted to the cooler air of higher slopes, there are fixed limits to how far they can move to find conditions conducive to survival. And yet well over half of the mountain-dwelling insects that have been studied are shifting upwards.