A tally of the number of insects crushed on car license plates suggests that the number of flying insects has fallen by almost 60% in less than 20 years.
The ‘Windshield Phenomenon’ Citizen Science Project is anecdotal evidence from drivers that they collect fewer moths, flies, aphids, bees and flying beetles on their windshields than they do did in the past.
Now a survey by Kent Wildlife Trust and Buglife has attempted to quantify this and gather more data on what is happening to insects in the UK, amid a global drop in insect numbers.
The Bugs Matter survey asked members of the public to record the number of flying insects squashed on their license plate in 2019 and 2021, and compare it to data from a survey conducted by the RSPB using the same method in 2004.
Before making an essential journey in their vehicle, drivers cleaned their license plates, then counted insects crushed on them using a “splatometer grid” provided as part of the survey.
They then submitted a photo and counted the details via the Bugs Matter app and the data was converted to “splats per mile” to make it comparable between rides.
The number of bugs sampled from vehicle license plates dropped by 59% between 2004 and 2021, the survey found.
Insects are crucial to a healthy environment, pollinating most of the world’s crops, performing natural pest control, breaking down organic matter and returning nutrients to the soil, conservationists said.
Counting insects provides an estimate of how they are doing in our cities and countryside, but also shows how the wider natural world is doing.
“We can no longer postpone the action”
The number of insects such as moths, butterflies, flies, flying beetles and ants, aphids, wasps, bees and lacewings differed across the UK, with England recording the most steep declines of 65% from 17 years ago.
Wales recorded 55% fewer insects, Scotland recorded a 28% drop from 2004 figures and there have been too few surveys in Northern Ireland to draw any separate conclusions, said conservationists.
Although the data showed significant declines in insect numbers, drawing strong conclusions about long-term trends in insect populations would require data over multiple years, long time periods, and large spatial scales.
Matt Shardlow, Managing Director of Buglife, said: “This vital study suggests that the number of flying insects is declining by an average of 34% per decade, it’s terrifying.
“We can delay action no longer, for the health and well-being of future generations this demands a political and societal response, it is essential that we halt the decline in biodiversity – now.”
Paul Hadaway, conservation director at the Kent Wildlife Trust, said the decline in insects reflected the huge threats and loss of wildlife more broadly across the country.
“These declines are occurring at an alarming rate and without concerted action to address them, we face a bleak future,” he warned.
“Insects and pollinators are essential to the health of our environment and rural economies.
“We need action for all of our wildlife now by creating larger and larger areas of habitat, providing corridors through the landscape for wildlife and allowing natural space to recover.”
• To take part in the Bugs Matter survey this summer, people can visit Buglife.