There is a thing older drivers remember that younger ones don't. Long road trips used to end with a windshield covered in insects — moths, beetles, flies, smeared across the glass in a way that required actual effort to clean. That stopped happening. Quietly, without announcement, the windshield just started coming back clean.
For a long time, people assumed it was the cars. Sleeker shapes, better aerodynamics, faster speeds that sent bugs flying around rather than into the glass. A reasonable explanation. Also wrong.
In 2019, researchers in Denmark adjusted for car model, speed, road type, and weather — all of it — and still found an 80% drop in insect strikes between 1997 and 2017. The UK ran standardised “splatometer” surveys using sticky plates on number plates. From 2004 to 2019: 50% fewer insects. By 2021 in Kent alone: 72%. By 2025 across the whole country: 59% down in just five years.
The windshield wasn’t getting cleaner because of better engineering. It was getting cleaner because there was nothing left to hit.
75% gone in protected areas
In 2017, a team of researchers published a paper that quietly changed how ecologists talk about insect loss. They had access to 27 years of data from malaise traps — tent-like nets that passively catch flying insects — set across 63 protected nature reserves in Germany. Not farmland. Not cities. Protected areas.
The result: flying insect biomass had declined by more than 75% overall. In midsummer, when insects should be at peak abundance, the drop was 82%.
This was not habitat loss within the reserves — those landscapes hadn’t changed. Something else was happening. Something that passed through fences and reserve boundaries and hit everywhere at once.
The windshield wasn't getting cleaner because of better engineering. It was getting cleaner because there was nothing left to hit.
By 2024, reviews of the global data were estimating 40 to 45% overall insect decline across 40 years. More than 40% of insect species are now considered threatened. And in 2025, a University of North Carolina study found a 72.4% drop in insects over 20 years in a remote Colorado subalpine meadow — a place with minimal human interference, no farms nearby, no obvious pressure. The decline was tied directly to warming summers.
That last detail matters. It means there is no pristine corner left to hide in.
Death by a thousand inputs
No single cause explains this. That’s part of what makes it hard to act on.
Neonicotinoids — the most widely used class of insecticides in the world — are systemic. They don’t just sit on the surface of a plant. They get absorbed into every part of it: the leaves, the stem, the pollen, the nectar. Bees and butterflies visiting treated flowers don’t die immediately. They come back disoriented. They can’t navigate. Their reproduction slows. A 2024 study linked insecticides directly to butterfly declines across the Midwest United States — more than herbicides, more than climate.
Habitat loss compounds everything. A bee that survives a pesticide-treated field still needs somewhere to overwinter, somewhere to nest, a corridor of wildflowers to feed from between one patch of land and another. Monoculture farming removes all of that. Light pollution disoriented nocturnal insects — moths especially — pulling them into artificial light instead of the dark routes they evolved to navigate.
Climate change then shifts the timing. Insects emerge earlier or later than the plants they depend on. The window of synchrony — the brief overlap between a flower’s bloom and an insect’s flight — shrinks or disappears. A caterpillar that should hatch alongside a burst of new leaves misses it by two weeks. It starves.
Each of these pressures alone might be manageable. Together, they compound in ways that are very hard to reverse.
What disappears when insects do
Insects represent more than 80% of all animal species on Earth. They are not a niche concern.
In the United States alone, insect-based ecosystem services — pollination, pest control, decomposition, soil health — are estimated at $70 billion a year. Global pollination services are valued at $215 billion. One in every three bites of food humans eat depends on a pollinator visiting a flower at the right moment.
96% of songbirds feed insects to their nestlings. Not seeds. Not berries. Insects — because insects are small, soft, and protein-dense in a way that nothing else is for a newly hatched bird. The collapse in insectivorous bird populations across Europe and North America tracks directly with the insect data. The birds are not disappearing first. They are disappearing because the insects already did.
The birds are not disappearing first. They are disappearing because the insects already did.
Soil health, nutrient cycling, the decomposition of organic matter — all of it runs on insects. An ecosystem without them doesn’t look like an ecosystem. It looks like a field that produces less, year after year, for reasons that are hard to trace back to a single decision anyone made.
What the science says to do
The 2025 meta-synthesis in BioScience named agricultural intensification as the dominant driver. That means the most direct lever is also the hardest one: changing how food is grown.
Reducing broad-spectrum pesticides — particularly neonicotinoids — is the most evidence-backed action. The EU banned outdoor use of three major neonicotinoids in 2018. Insect populations in treated areas showed partial recovery within a few years, though not full recovery. Restoration of wildflower margins along field edges, hedgerows, and habitat corridors costs relatively little and shows measurable results within a single season.
At the individual level: planting native species, reducing or eliminating garden pesticides, and turning off exterior lights at night all contribute. Citizen science programs like Bugs Matter in the UK, which trains volunteers to count insect strikes using splatometer kits, are generating the kind of consistent long-term data that makes trends visible.
The monitoring gap is real. Most insect data comes from Europe and North America. We know almost nothing about trends in tropical regions — which contain the highest insect diversity on the planet, and which are also facing the fastest habitat conversion.
The quiet summer
Oliver Milman wrote The insect crisis in 2022 — a book that laid out the scale of this problem for a general audience, clearly and without catastrophism. Rachel Carson did something similar in 1962 with Silent spring, which named the pesticide problem decades before the data caught up. Isabella Tree’s Wilding documents what happens when you stop managing land intensively and let insects, birds, and plants reorganise themselves — the recovery is faster than most people expect, and more complete.
The windshield is a small thing. A piece of glass at the front of a car. It means nothing on its own.
But it is a measurement. And what it is measuring, every summer, on every road in the northern hemisphere, is a world with fewer living things in it than the summer before.
The question is not whether we have noticed. We have. The question is whether noticing is enough.
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