Survey shows ongoing decline in flying insects in Wales

Emily Price

The “troubling” extent of insect declines across Wales has been highlighted by the results of a citizen science survey published today.

The latest data gathered in 2024 by Bugs Matter shows that the number of flying insects sampled on vehicle number plates, across Wales, has fallen by 64% since 2021.

The survey, led by Kent Wildlife Trust in partnership with invertebrate charity Buglife, relies on a nationwide network of volunteer citizen scientists who record insect splats on their vehicle number plates after journeys.

Decrease

Analysis of records from more than 25,000 journeys across the UK since 2021 shows a sharp decrease in bug splats – but data from 2024 shows this decrease has slowed.

Insects are critical to ecosystem functioning and services. They pollinate crops, provide natural pest control, decompose waste and recycle nutrients, and underpin food chains that support birds, mammals and other wildlife.

But their numbers are dwindling due to habitat loss, pollution, pesticide use and climate change.

Without insects, the planet’s ecological systems would collapse.

‘Stark’

Dr Lawrence Ball of Kent Wildlife Trust said: “The results from the Bugs Matter survey are really concerning. We are probably detecting insect declines as they are happening, which reflect the enormous threats and loss of wildlife more broadly across the UK.

“These declines appear to be 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.”

The new data shows a decrease in insect splat rates across all the UK nations, with the sharpest fall recorded in Scotland – 65% between 2021 and 2024.

In England, the number of insect splats fell by 62% and in Northern Ireland by 55%, over the same time period – with an overall average decrease across the entire UK of 63%.

Dr. Lawrence Ball of Kent Wildlife Trust said: “This huge decrease in insect splats over such a short time is really alarming. It’s most likely that we are seeing the compounding effects of both a background rate of decline as well as a short-term cycle of decline, perhaps linked to the extreme climate in recent years.

“Bug splats declined 8% from 2023 to 2024, following sharper drops of 19% in 2023 and 52% in 2022. This shows the rate of decline has slowed and it may even flatten or reverse next year.

“Continued support from citizen scientists is key to revealing the overall trend in insect numbers.”

‘Unviable’

The charities have warned that that the current pace of decline is “clearly ecologically unviable”.

Organisers of the Bugs Matter survey say that by taking part each year, citizen scientists can provide crucial data to better understand insect population patterns and support evidence-based conservation actions.

Buglife Cymru’s Clare Dinham said: “The latest Bugs Matter data suggests that the abundance of flying insects in our countryside has fallen again. But we can turn the tide.

“We need more space for nature – so more habitats restored at scale, connected across whole landscapes. We need safer places for wildlife – which means reducing our use of pesticides and other pollution of land and freshwater.

“Thank you to everyone who participated in the Bugs Matter survey in 2024. Your contribution has provided invaluable insights into the health of our insect populations and wider environment across Wales. We are relaunching the survey on May 1 this year, and we hope to engage even more people in this crucial citizen science effort.”

The 2025 Bugs Matter survey will run from Thursday 1 May to Tuesday 30 September.

It is quick, free and easy to get involved – simply download the free mobile phone app and start recording insect splats on vehicle journeys.