Squashed bugs on number plates suggests ‘terrifying’ Scottish insect declines

If the state of the nation’s vehicle registration plates are to be believed, the number of flying insects in Scotland has declined by nearly 30 per cent in less than 20 years.

In a highly creative study, a citizen-science survey monitored the number and different species of insect found squashed on number plates across the country.

Using the ‘splatometer’ method, and with expert guidance by Kent Wildlife Trust and Buglife, researchers found the abundance of flying insects in Scotland has plummeted by nearly 30 per cent over the past 18 years.

The study has highlighted a worrying trend and the crucial need for insect-focussed conservation research.

Small Heath butterfly is disappearing from our countryside (Coenonympha pamphilus) Pic: Darren Bradley

The 2021 Bugs Matter findings, which are published in a report released by Kent Wildlife Trust and Buglife, show the number of insects sampled on vehicle number plates by citizen scientists across Scotland decreased by a staggering 27 per cent between 2004 and 2021. These findings are consistent with research that has widely reported declining trends in insect populations globally.

Insect counts differed across the UK and England suffered the greatest decline with 65 per cent fewer recorded in 2021 than in 2004. Wales recorded 55 per cent fewer insects, whilst Scotland saw the smallest decline, still with 28 per cent fewer insects in 2021 when compared to 2004 figures. There were too few surveys conducted in Northern Ireland to analyse and draw conclusions.

Inspired by the ‘windscreen phenomenon’ – the number of insects squashed on the windscreens of cars today compared to several decades ago – Bugs Matter enlists the help of the public to monitor the health of the UK’s insect populations.

The concept is simple – before making an essential journey in a vehicle, clean the number plate. After each journey, count the insects squashed on the number plate using a ‘splatometer’ grid, which is posted to you when you download the free Bugs Matter app. A photo and count details are submitted via the app.

Most species of the humble bumblebee are under threat Pic: Dan TP

Insects and other invertebrates are critical to a healthy functioning environment. They pollinate most of the world’s crops, provide natural pest control services, decompose organic matter and recycle nutrients into the soil. Without them, life on earth would collapse.

Counting insects is a measure of the health of our environment and the results can shape how the work of conservation organisations and others is helping nature’s recovery.

Natalie Stevenson, Scotland and Northern Ireland Manager at Buglife, said: “This vital study suggests that the number of flying insects is declining by an average of 34 per cent per decade. This is terrifying. We cannot put off action any longer, for the health and wellbeing of future generations this demands a political and a societal response. It is essential that we halt biodiversity decline – now.”

Paul Hadaway, director of conservation at Kent Wildlife Trust, added: “The results from the Bugs Matter study should shock and concern us all. We are seeing declines in insects which reflect the enormous threats and loss of wildlife more broadly across the country.

The Lacewing (Chrysopa perla)is among insect species declining in Scotland Pic: Jaybee

"These declines are happening at an alarming rate and without concerted action to address them we face a stark future.

"Insects and pollinators are fundamental to the health of our environment and rural economies. We need action for all our wildlife now by creating more and bigger areas of habitats, providing corridors through the landscape for wildlife and allowing nature space to recover.”

Experts say the 'splatometer' gives a remarkably accurate count of insect numbers. Pic: Bug Life