Many people remember summer nights with moths and mayflies circling porch lights, or road trips that left windshields splattered with insects. Some may have the uneasy feeling that things have changed.
Scientists say those memories point to something real: many insects are becoming less abundant in Canada and around the world, with consequences for birds, bats, fish, plants and people.
In southern Ontario, York University PhD student Hadil Elsayed found the total mass of insects collected at two protected sites had fallen by roughly half since the 1990s. In the U.K., a citizen-science project measuring insect splatter on license plates has documented a steep drop in flying insects. Many other studies document insect declines around the world.
A huge loss of tiny creatures
In the summers between 2021 and 2023, Elsayed trapped insects to measure populations at Long Point National Wildlife Area and St. Williams Conservation Reserve in southern Ontario, painstakingly replicating a survey conducted by Environment Canada in the early 1990s.
Elsayed is preparing to submit her findings, part of her PhD dissertation, to a journal. Although the results have not been peer-reviewed for publication, they show that over the past 30 years, the total mass of insects trapped had roughly halved, from 645 grams to 333 grams.
Her findings are consistent with a study published in June by researchers at the University of Michigan and Birds Canada. That study found flying insects at the nearby Long Point Bird Observatory declined 62 per cent between 1977 and 2011.
A large proportion of the insects Elsayed collected were minuscule flies called midges, insects so tiny they weigh almost nothing. Despite their size, they’re an important, nutritious food source for fish, other insects, birds and bats.
The loss Elsayed measured is equivalent to about 640 million midges.
“It’s an insane number of insects,” she said. Although the results were not surprising, Elsayed called them “heartbreaking.”
Flies, including midges and mosquitoes, were the hardest hit in both studies. Elsayed also found declines in butterflies and beetles too.
“We’re not just losing our rare species, we’re losing a lot of individuals from common groups as well.”
How big and bad is the problem?
Conservationist Andrew Whitehouse said the decline of common species may be more worrying than the extinction of rare ones “because it’s probably the more common widespread abundant things … that keep everything running.”
Those functions include pollinating plants and breaking down dead and rotting plants and animal matter.
Whitehouse is head of operations at Buglife in Plymouth, England, a group focused on insect conservation — and there’s ample evidence worldwide that insects need conserving.
A study published last spring found a decline in U.S. butterflies so stark that it brought scientists to tears. A 2019 study found that worldwide insect declines could lead to the extinction of 40 per cent of insect species within decades, although studies covering different periods have found wide variations among groups and regions.
A collection of studies in 2021 suggested insects were disappearing at a rate of one to two per cent per year.
Researchers commonly point to habitat loss, invasive species, pesticides and pollutants and climate change as major pressures on insects.
Shrinking swallows
The loss of insects is already being felt by other species.
The Birds Canada study published in June found that insect-eating swallows are becoming smaller and less numerous as their food source dwindles.
Humans, other animals and plants that don’t eat insects still rely on them for pollination, pest control and their role in the food chain.
Insects also touch our lives in more subtle ways.
In England, Whitehouse said, many people noticed their car windshields, grilles and licence plates have become uncannily cleaner because of fewer insect splatters.
Buglife created a citizen-science project called Bugs Matter to document the change using photos of people’s licence plates after they drove.
Between 2021 and 2025, the project found a 59 per cent decline in flying insects in the U.K. and Ireland — “pretty scary stuff,” Whitehouse said.
Buglife is expanding the survey to more regions, and said it might even come to Canada in the future.
A close-up view of nature
The insects around us also provide a unique local, up-close view of nature.
Whitehouse developed a fascination with insects as a boy in England, while hunting tadpoles and finding stranger six-legged creatures in and around their ponds.
His favourite is the bloody-nose beetle.
“If it’s threatened by a predator, like a bird, it can squirt its body contents out through its face and they’re bright red — which puts the bird off.”
Elsayed’s love of insects developed when she got a job looking through a microscope at parasitoid wasps — the inspiration behind the Alien movies, where parasitic creatures burst from the bodies of their human hosts.
In nature, the scenes play out on a smaller scale. The wasps are often less than a millimetre long.
“Some of them were so tiny, but they could wreak such big havoc on these much larger insects,” Elsayed said.
In her current work, she is excited by the variety of insects she is seeing for the first time, including rare ones. But she’s also saddened by the declines in all kinds of insects she has noticed even in the past five years.
“I’m just seeing lost insects across the board.”
What can help
The good news, Elsayed and Whitehouse said, is that many insect declines can be reversed if people take action by planting more native vegetation, preserving habitat and cutting back on pesticide use.
There are cases where insect populations have bounced back.
A recent 90-year study in Switzerland found beetles and butterflies started declining steeply in the mid-20th century, especially species adapted to colder climates. But in the past three decades, beetles that prefer warmer climates have been recovering.
The researchers suggested they’ve benefitted from deadwood being left in forests as insect habitat, along with environmental measures to promote natural areas on farmland.
Whitehouse said creating more connected, natural “safe” spaces for nature is key.
“I do think we can change this,” he said, “but we need to bring a lot of people with us and people need to care.”
This is part of a series of articles highlighting the work of scientists looking at disappearing groups of species you may not have thought much about. It’s a chance to get to know them and how they impact our lives, and find out what can be done to keep them around.
Have you noticed fewer bugs around the last few years? Experts say there’s growing evidence that Ontario’s insect population is shrinking. CBC’s Talia Ricci visited a GTA nature reserve to learn more.
