Two scientific studies of the number of insects splattered by cars have revealed a huge decline in abundance at European sites in two decades.

The research adds to growing evidence of what some scientists have called an “insect apocalypse”, which is threatening a collapse in the natural world that sustains humans and all life on Earth.

The survey of insects hitting car windscreens in rural Denmark used data collected every summer from 1997 to 2017 and found an 80% decline in abundance. It also found a parallel decline in the number of swallows and martins, birds that live on insects.

Swallows

The second survey, in the UK county of Kent in 2019, examined splats in a grid placed over car registration plates, known as a “splatometer”. This revealed 50% fewer impacts than in 2004. The research included vintage cars up to 70 years old to see if their less aerodynamic shape meant they killed more bugs, but it found that modern cars actually hit slightly more insects.

“This difference we found is critically important, because it mirrors the patterns of decline which are being reported widely elsewhere, and insects are absolutely fundamental to food webs and the existence of life on Earth,” said Paul Tinsley-Marshall from Kent Wildlife Trust. “It’s pretty horrendous.”

Insect population collapses have been reported in Germany and Puerto Rico, and the first global scientific review, published in February 2019, said widespread declines threatened to cause a “catastrophic collapse of nature’s ecosystems”. Insects pollinate three-quarters of crops and another recent study showed widespread losses of such insects across Britain.

The causes of decline are the destruction of natural habitat, pesticides and the impacts of the climate crisis. Light pollution has also been cited as a key “bringer of insect apocalypse”.

Matt Shardlow, the chief executive of the charity Buglife, said: “These new studies reinforce our understanding of the dangerously rapid disappearance of insect life in both the air and water. It is becoming clear that the four horsemen of the insect apocalypse are climate change, habitat destruction, habitat fragmentation and pollution. It is essential we create more joined-up space for insects that is safe from pesticides, climate change and other harm.”

Most scientific research to date has shown serious declines in the number of insects in the places studied. “There is no doubt about this,” said Møller. “What there is slight doubt about is the extent to which this occurs across geographical and temporal scales.”

Long-term studies are rare and mostly from Europe and North America, with a few ranging from Australia to China and Brazil to South Africa, but hardly any elsewhere. There has also been discussion about the best methodologies among researchers.

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