It sounds like another one of those dire “climate change” warnings – and in fact, it largely is. Some amateur entomologists – scientists that study bugs – say that the world’s insect population is under siege, and as a result birds and plants and indeed, our entire food production system is in danger.
The evidence supporting the forecast of an “Insect Apocalypse” is spotty at best. What typically happens is that a researcher collects data on insect population declines in a small area of the world and begin recklessly extrapolating – largely because it draws attention to their work.
For example, a 2015 study often cited by those fearful of a massive insect decline found a total of 117,000 dead insects along a 2-kilometer stretch of highway in Ontario, Canada. The authors misused this data to estimate that “hundreds of billions” of insects were being killed not just across Canada but throughout North America.
“We just have no idea if that’s true,” says Kaitlin Whitney, an insect ecologist and assistant professor at the Rochester Institute of Technology. “There’s no reason to believe that declines or even road mortality from one highway stretch in Canada is indicative of what’s happening across the rest of the continent … We just don’t have global surveillance of insects to be able to make a reasonable estimate like that.”
It turns out that insect levels – like climate trends — can also fluctuate wildly, with peaks and valleys and no obvious long-term trend.
Many scholars, especially PhD students, are constrained by their research funding cycle, which only allows them to study insects in short-term intervals. In reality, they have no way of knowing how typical the findings from their narrow study period might be.
More research would help, but it’s extremely difficult to get funding for longer-term insect inventories, critics say.
Even when researchers do manage to compare insect population at longer intervals, their data may be too limited to arrive at sweeping conclusions.
Take the example of cicadas, which have lengthy underground gestation periods. Most of the argument about their decline is based on research conducted in one locale — Puerto Rico — where data was collected just a handful of times in two periods — more than four decades apart.
Critics say data collected this way at best represents snapshots in a complex ever-changing environment, and it’s absurd to try to tease out a “trend” from such findings.
Another problem is the way insect populations are often measured, in terms of their overall “biomass” and based largely on flying insects alone. Insects that crawl on the earth or on plants and trees or swim – which may outnumber their airborne counterparts — are completely missed in these studies.
Can any broad conclusions about the fate of insects be reached based on available research?
Not really. It turns out that little is known about insects and the complex ecological roles they play in different environments around the world. And entomology departments that study insects have declined in size and funding at universities the world over.
This means that even as insect populations continue to diversify, the research resources to study them is shrinking.
There is also a strong geographic bias in the research conducted thus far, which tends to focus on Europe and North America. According to a study published in 2018, only 20% of the planet’s insect species have been identified and named thus far. In Africa, Asia, and Latin America, where insect diversity stands unparalleled, most species are still unknown to science, experts say.
With such a limited knowledge base, making bold predictions about the fate of insects is worse than risky – it’s downright irresponsible.
Whitney and others note that the “ecological Armageddon” paradigm is so pervasive that scientists often miss important new discoveries — or have no way of explaining them when they do
For example, in New Zealand earlier this year, field researchers extracted and analyzed DNA from the soil of the small forested island of Hauturua – and to their surprise, found up to 2,500 new insect species.
In fact, new species are being discovered every day. Studies in some locales suggest that some insect populations may be growing, not declining, for reasons still unknown.
Nature, it seems, is enormously resilient. But then, so are the arguments of the doomsayers.