In the realm of insects, where the buzz of translucent wings and the patter of tiny feet reign, something troubling is unfolding: these small animals are quickly vanishing from the world.
But how do scientists detect insects’ often silent disappearances?
Because they’re tiny and often well hidden, detecting and preventing extinctions is no easy feat, explains Eliza Grames, a postdoctoral researcher at University of Nevada, Reno. “There are so many different things contributing to insect declines and it's not the same for all [groups] – it’s death by a thousand cuts,” Grames says.
Is Our Insect Population Declining?
Growing concern over the precipitous drop in insect populations has led some scientists to declare an "insect apocalypse." While some extinctions are a natural part of evolution, human changes to the environment are causing unprecedented declines and disappearances.
Over a million insect species are known to science. Experts guess, however, that there could be five to six times that many waiting to be described – but they may be lost before we can do so.
Threats to insects and other small critters are myriad: habitat loss through deforestation and urbanization; widespread use of pesticides; climate change-worsened drought, wildfires and storms; introduction of invasive species.
“We're seeing a decline across many, many different studies,” explains Grames, “which is where the concern really comes from. It's not just that insects are declining in Germany. They're declining in the U.S. They're declining in Brazil. They're declining in Costa Rica. It's everywhere.”
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Why Are Insects Important?
Those ants or cockroaches are more than pests that ruin picnics or hide in our bathrooms – they carry out essential jobs that both ecosystems and humans rely on.
“Insects are really important for ecosystem function, so it's not just about the insects, it’s about all of biodiversity,” says Grames.
These tiny creatures are responsible for up to 75 percent of crop pollination – and we’re not just talking about bees. Butterflies, beetles, moths, midges and more ensure the reproduction of countless agricultural plants.
Food for Other Wildlife
Insects are also a fundamental food source for countless creatures across the animal kingdom, including bats, birds, mammals and fish. This makes insects an irreplaceable link in the web of life, so that when insect populations decline or disappear altogether, other species can vanish along with them.
Decomposers provide essential ecosystem waste management services. Dung beetles keep the world from becoming covered in excrement and decaying animals. Termites break down logs and other organic matter. These and other insects play a vital role in taking nature’s trash and cycling it back into valuable nutrients that can be used by other organisms.
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Does Our Insect Population Fluctuate?
With their short lives and high mobility, insect populations can fluctuate in time and space. For instance, local extinctions and reappearances can occur in response to natural disasters or other habitat disruptions. Or, a species can vanish somewhere only to pop up in a place they’ve never been seen before because conditions in their old habitat were no longer livable.
Because of these and other factors, Grames explains, determining whether an insect is truly gone is a complex puzzle that makes scientists hesitant to declare a species extinct.
How Are Extinct Insects Made Official?
Declaring an insect extinct comes with it a healthy dose of uncertainty. It’s much easier to know that there are no more Tazmanian tigers than to be sure we haven’t missed a hidden Ridley’s stick insect or Central Plains locust.
“The guidelines for extinction have historically been based on large, charismatic vertebrates,” explains Grames.
Scientists, however, make highly educated guesses based on data, both on insect populations and the drivers of insect declines.
Should We Conduct Long-Term Insect Research?
Long-term research is key for knowing when insects are teetering on the brink of extinction – or when they have succumbed to non-existence. However, there is a dearth of these invaluable multi-decade studies.
“That’s one of the hard parts of trying to figure out [extinction patterns]. We don’t have time machines to go back in time and start a long-term monitoring effort back in the fifties or sixties,” says Grames.
While we cannot change the past to gather comprehensive information on insects, old data and emerging technologies are making the study of these creatures more accessible and informative.
Insect collections in museums, for example, can provide invaluable snapshots of historic insect communities. Additionally, weather radars, initially designed for tracking atmospheric conditions, are being repurposed to retrospectively examine large-scale insect emergences.
Technologies like the use of environmental DNA (eDNA) allows researchers to detect traces of insect DNA that are invisible to the human eye. By collecting and analyzing samples from the environment – such as water, soil or air – scientists can identify the presence of specific insect species.
What Is the Future of Insects?
Confirming insect extinctions is a science, albeit an imprecise one. As researchers strive to understand these troubling trends, innovative approaches combined with long-term research may help unravel the mysteries surrounding the extinctions, and conservation, of insects.
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