Imagine driving down a highway in the summer. The windows are down, the music is loud, and the wind is whipping through your hair. Now picture your car's windshield. You might expect to see a handful of splats from unfortunate bugs. But 30 years ago, there would have been significantly more buggy skid marks plastered on the front of your vehicle.
"When I was a kid, you could go out driving in the summer, and you would come home and your car windshield was covered in bugs," said Cheryl Schultz, an ecologist at Washington State University. "Now, you can go across many areas at the same time of year and your windshield is clean."
This phenomenon, called the "windshield test," is indicative of a larger, very worrying trend: Insects, particularly the flying ones that pollinate many crops, are in steep decline. This nosedive is disrupting ecosystems around the world, and could jeopardize the global food supply. But tracking the decrease of insect populations over the past three decades has proved tricky — and stopping the decline may be even harder.
However, researchers are working quickly to find ways to stem the tide and even reverse the trend. Key to that is a collaborative approach that includes local and federal conservation efforts, new pollinator habitats, and a reduction in pesticide use.
The age of the "insect apocalypse"
Both the total number of insects and the number of insect species have been declining for decades in pretty much every place scientists have looked — prompting researchers to dub it "the insect apocalypse." Global bee biodiversity is down 25% compared with pre-1995 numbers, according to research published in 2021. A sweeping 2025 study showed that butterfly abundance across the U.S. fell by 22% over the past two decades. And a study in Germany found a whopping 76% loss of flying insects in some of the country's forested areas over 27 years.
"It's a worrisome thing," Scott Black, executive director of the nonprofit Xerces Society for Invertebrate Conservation, told Live Science.
By and large, experts know why insects are becoming scarcer. The first factor is climate change. As the planet warms, key host plants for insects start to bloom earlier each year. This can cause a mismatch in life cycles for certain species, putting many newly hatched or metamorphosed bugs out of sync with their food sources. And extreme heat, reduced snowpack, severe storms and megadroughts can chip away at previously robust insect numbers. Many populations simply can't keep up. Meanwhile, milder winters can benefit a few adaptable pest species, which may outcompete sensitive insects and wreak ecological and agricultural havoc in some regions.
The second driver is habitat loss — the inexorable creep of urbanization, deforestation and sterile suburban lawns, which host fewer and less-diverse ranges of insects. As humans encroach on insect habitats, insects like ground-dwelling bees are left without space to build nests, rear young and overwinter, leading to population declines.
Finally, there are pesticides. For instance, neonicotinoids (often labeled as the active ingredients acetamiprid, clothianidin, dinotefuran, imidacloprid and thiamethoxam), have been identified as a major threat to wild bees, and they're still used in the U.S. and some other industrialized countries, including parts of Canada and Australia. Other pesticides, like the common weed killer glyphosate, have been shown to weaken bees' ability to regulate hive temperature, leaving them vulnerable to plunging winter temperatures.
"It's really extremely rapid environmental changes that we're seeing," Roel van Klink, a researcher at the German Center for Integrative Biodiversity Research, told Live Science. "Those species that were adapted to the conditions that we had maybe 50 or 100 years ago are not adapted to the conditions now anymore. And so they go down."
Collecting data on the scale and scope of these declines has been challenging, however. For one thing, some insects are easier to find than others. Flying insects like beetles and dragonflies are much more mobile, and therefore easier to spot, than earthbound bugs like earwigs and ants. Likewise, charismatic insects like bees and butterflies tend to have more historical records of their numbers and are usually easier to identify.
But there's another reason these insects' declines have gotten more scientific attention: They are extremely important for global food security.
The importance of diverse pollinators
Disappearing insects are bad news for the global food system. As the world's population continues to grow, the stress that insect declines — and dropping pollinator numbers, in particular — put on the food system could lead to an agricultural economic collapse, as well as increased food scarcity.
"Preventing further declines is no longer enough," Francesca Mancini, an ecological modeler at the UK Centre for Ecology & Hydrology, told Live Science. "We need to restore insect biodiversity to past levels."
In the U.K. alone, insect pollinators provide an estimated $1 billion in economic value each year, Mancini said. For the U.S., it's in the ballpark of $34 billion.
Worldwide, three-quarters of the crops we eat — and just over one-third of total crop yields — depend on pollination by insects.The degree to which these crops rely on pollinators falls along a spectrum. Some, like soybeans, would be much less productive without insect pollination. Others would cease to exist. "Coffee and chocolate are actually 100% dependent on pollination by insects," van Klink said.
A lot of that pollination work is done by managed European honeybees (Apis mellifera), which beekeepers around the world diligently maintain, transport and unleash upon fields across the globe each year. But to flourish, many crops need more than just honeybees.
For example, fruits native to North America, like blueberries and tomatoes (which is technically a fruit), are more effectively pollinated by native bumblebees, such as Bombus fraternus. That's because bumblebees can perform what's known as "buzz pollination," where they land on a flower and vibrate rapidly to release even the most deeply held pollen grains. Cacao trees (Theobroma cacao) — the source of the cocoa beans used to make chocolate — are entirely pollinated by chocolate midges. And cotton yields would plummet by up to 50% without butterfly pollinators.
Some staple crops, like soybeans, can make it without insects. However, research has shown that soybean fields visited by pollinators have significantly higher yields.
Then, there are crops like alfalfa (Medicago sativa). This legume isn't widely consumed by humans, but it is a staple for livestock — particularly dairy and beef cattle. Like blueberries and tomatoes, alfalfa depends on insect pollinators to thrive. However, honeybees will only pollinate it reluctantly; given the choice, they'd rather buzz around plants with flowers that are easier for them to access. But wild bees, particularly the alfalfa leaf-cutting bee (Megachile rotundata), are extremely effective alfalfa pollinators.
A recent study found that alfalfa fields visited by a mix of honeybees, wild bees and other pollinators, like wasps and butterflies, produced significantly more and larger seeds than fields visited by honeybees alone. This higher yield translates to more food for cattle — and thus more milk, cheeseburgers and steaks for us.
Glimmers of hope
Of course, restoring insect abundance and biodiversity is no easy task, especially in the face of an all-encompassing threat like global climate change. Experts told Live Science that coordinated federal regulations aimed at slowing climate change, reducing industrial pesticide use, and preventing the destruction of wild spaces are essential for protecting insects. But there are also actions people can take at the local and personal level that can have a positive impact.
Although the current U.S. administration's cuts to federal science programs and green energy have dealt a harsh blow to progress on these fronts, many experts still see reasons for optimism.
"As much as the overall picture is overwhelming, there's lots of places for hope," Schultz told Live Science. In a detailed report about the state of U.S. butterflies written this year in collaboration with the Xerces Society, Schultz highlighted a number of "success stories" — species that bucked the trend and increased in abundance thanks to years of focused work at both the federal and local levels.
Chief among them is the Fender's blue (Icaricia icarioides fenderi), a tiny azure butterfly native to Oregon. In 2000, the U.S. Fish and Wildlife Service listed it as endangered. In 2023, it became the second-ever insect to be downlisted to "threatened."
And the benefits of conservation efforts for one species had knock-on effects: Of the 342 butterfly species and subspecies analyzed in the report, 65 others had increased in number, and most were not on the endangered species list. This suggests that protections to conserve one insect could benefit others as well.
Increasing healthy habitat
One of the best ways to help butterflies and other pollinators is to create more habitat for them. Unlike grizzly bears or elk, these insects don't need large stretches of unbroken wilderness. Even something as small as a backyard butterfly garden or a flower-filled window box can go a long way, Wendy Leuenberger, an ecologist at Michigan State University, told Live Science.
One study in the Pacific Northwest found that converting a 5,400-square-foot (500 square meter) plot of land — roughly half the size of the average American lawn — into an insect-friendly habitat full of native or wild plants can increase pollinator species' richness and abundance by about 90%. However, that effect was fairly localized, and it dissipated when these patches were placed in plots of more than 150,000 square meters (37 acres) — about the size of seven or eight blocks in Chicago.
Some pollinators, like hoverflies (Syrphidae spp.) and certain types of bees, can cover miles in search of flowering plants. But others, including many butterflies, tend to stay closer to home — within a 650-foot 200 meter radius for more delicate species. This suggests that plots of native or wild flora are most effective at bolstering our food supply when interspersed within larger agricultural fields.
"I would say it's the closer, the better for your crops," Andy Grinstead, a conservation manager at Pollinator Partnership, told Live Science.
In agricultural communities, experts like Grinstead recommend planting "buffer strips" of native vegetation near (or, if possible, in between) crops. He also suggests planting hedgerows of woody, flowering plants around fields to act as both pollinator habitat and wind protection. But you don't have to be a farmer to support pollinators. Folks living within a few miles of farms can plant "bee lawns," which are filled with low-growing flowering plants like clover, instead of pure turfgrass.
And for those without yards, growing micro-plots of native wildflowers — even just a pot on a rooftop or balcony or hanging from a window — can create green "stepping stones" for bees, hoverflies, migratory butterflies and beetles passing through urban areas.
"Pollinator-friendly practices are valuable across all landscapes," Grinstead said. "It takes very little space to actually make an impact."
Reducing pesticide use on an industrial scale can also benefit pollinators, Black said.
One way to do this is to adopt an integrated pest management framework. This can mean rotating crops to keep soil healthy; accurately identifying pests before applying pesticides; and carefully spraying in targeted areas (away from blooms) when the wind is low to prevent the pesticides from drifting into the surrounding environment.
But even home gardeners can help reduce pesticides by replacing lawns or ornamental plants with hardier native species, hand-weeding rather than blanket-spraying small plots, and using screens or draining standing water instead of spraying for pests like mosquitoes, Black said. Taken together, these actions can help create havens where pollinators can thrive.
Taking action
Crucially, scientists are still researching the full scope of global insect declines, especially for species that have been historically understudied. This means we need field research to estimate insect numbers, Black said.
Community pollinator counts, whether as part of a formal program or through apps like iNaturalist, are also essential, Leuenberger told Live Science. These data help experts pinpoint which species are most vulnerable and which conservation efforts are most effective.
But with the future of the global food system hanging in the balance, it's important to try to restore these numbers now — not wait till researchers have published comprehensive data on how and where insect numbers are plummeting, Black said. "We don't want to wait until we have everything tucked into a perfect paper before we take action," he said. "We know how to take action."