17
May
Study of Dramatic Flying Insect Declines Reinforces Earlier Findings
(Beyond Pesticides, May 17, 2022) With public awareness of an ongoing ‘insect apocalypse’ growing, one of the first anecdotes people often note is how many fewer bugs are found splatted onto their car windshield than in the past. In a recent survey, conservation groups in Britain are finding evidence of insect declines in exactly that place, providing scientific backing for these concerning suspicions. Between 2004 and 2021, 58.5% fewer flying insects were squashed onto car license plates. “The results from the Bugs Matter study should shock and concern us all,” says Paul Hadaway, conservation director at Kent Wildlife Trust, which conducted the study alongside UK organization Buglife. “We are seeing declines in insects which reflect the enormous threats and loss of wildlife more broadly across the Country. 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.”
The survey was conducted primarily through citizen science, utilizing the “Bugs Matter” mobile app, and a sampling grid, referred to as a ‘splatometer’ that is affixed to a car’s license plate. Data was retrieved from trips taken by citizen scientists between June 1 and August 31 in 2004 and 2021. Locations and trip distance was written down in 2004, but automatically tracked via the app in 2021. Trip speed generally averaged under 30 miles per hour, and trip length ranged between an average of 16 to 36 miles.
Analysis of the survey results determined a splat rate of .238 insect splats per mile in 2004, but only .104 per mile in 2021. Within that period, the odds of taking a trip and seeing no insects squashed to one’s license plate increased by 2.9 times. Differences were seen between different areas of the United Kingdom. Scotland witnessed the smallest decline, at 28%, which could be attributed to the region having more wild land and fewer farms and cities. England, on the other hand, saw the greatest declines, at 65%, while Wales recorded losses of 55%. (Data was not available for Northern Ireland).
These results line up with the latest data on the insect apocalypse from peer-reviewed scientific literature. Published in Nature, a recent study found that in the context of climate change, low intensity agriculture and expansive natural habitats provided the best chance to reduce insect losses. The more wildland regions have surrounding their farmland, the better insects are expected to fare. The difference between the results observed in Scotland and England line up well with that modeling.
“This vital study suggests that the number of flying insects is declining by an average of 34% per decade, this is terrifying,” said Matt Shardlow, CEO at Buglife. “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!”
Research published in 2017 rose a major red flag for insect populations worldwide, finding that in German nature preserves, 75% of flying insect biomass had been lost. A systematic review of insect population decline studies subsequently published in 2019 determined that 41% of insect species worldwide are declining. Declines of butterflies, wild bumblebees, and honey bees are specifically linked to hazardous pesticide use in industrial agricultural systems. Worldwide, roughly a quarter of the global insect population has been lost since 1990, according to research published in Science. This research finds worldwide trends in declines in terrestrial insect biomass to be nearly 1% each year (~9% each decade).
As a 2019 review concluded, “We know enough to act now.” Across the globe, data continues to line up with people’s anecdotal experiences of seeing fewer and fewer insects as the years go by. Unless we act soon, ecological amnesia will set it, as subsequent generations will perceive the environment in which they were born as the norm.
Consider the decline of insects in the context of efforts to stop the deaths of eagles, falcons, condors, and other birds of prey in the 1960s from widespread DDT use. Field observations of broken eggs in Peregrine falcon nests in Britain the late 1960s led to populations surveys. In the United States, most longstanding falcon nests were found deserted. Massive increases in pesticide use following World War II was suspected as the cause, and it was confirmed that as DDT bioconcentrated up the food chain, it would be contained in eggshells. DDT concentrations in eggshells correlated in lock step with the thinness of an eggshell, scientifically confirming the issue.
With pollinators and the wider insect world, we are at a similar moment. We know that industrial agriculture and its use of hazardous pesticides, particularly systemic insecticides like the neonicotinoid class, are harming insect life and biodiversity throughout the globe. Scientific data is now so sophisticated we can provide year by year and decade by decade models of insect declines both past and future.
It took 10 years after Rachel Carson wrote Silent Spring for DDT to be banned. Yet, it has taken decades for bird of prey populations to bounce back. On the east coast, local populations of Peregrine Falcons were extirpated, and needed to be reintroduced over subsequent decades. It was not until 1999 that populations recovered enough to remove the birds from the endangered species list. Bald eagles were only removed from endangered species status in 2007. It was in early May that wildlife officials and the Yurok Tribe were able to reintroduce California condors into Northern California.
How many readers have anecdotally noticed more birds of prey in their region, but fewer pollinators and other insects?
The lag time between precipitous declines and species recoveries are often decades-long affairs. As we cheer the return of birds of prey we must likewise lament the years lost without them unnecessarily and shortsightedly, and be cognizant of the ongoing harm chemical use is causing to animals that form the basis of all ecological food chains. The work to ensure future generations can experience a world where “the bees are coming back” must start now.
For more information on ongoing insect declines, see Beyond Pesticides article Tracking Biodiversity: Study Cites Insect Extinction and Ecological Collapse. See here for more resources to get engaged and collect crucial ecological information through citizen science projects.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: BugsLife UK press release, BugsLife/Kent Wildlife Trust Technical Report
I live in far north Idaho, 25 years here. Used to be these warm summer nights the moths would come by the hundreds to the windows at night. They are 99% gone in the last 5 years.
June 28th, 2023 at 1:34 am