The decline of insect species might seem to some like a step in the right direction, or at least like a minor concern. But in reality, the looming extinction of many insect species, described in a new report, is another alarming sign that we’re entering an ecologically precarious period. Insects are vital to the same ecosystems that we depend on for food – and that’s only a small example of our reliance on insects.
The new paper, published in the journal Biological Conservation, reviewed 73 prior studies and found that 40 percent of insect species could face extinction in the next few decades. Over 40 percent have already seen declines over the last decade, and the total mass of insects on the planet is now declining by 2.5 percent annually.
“It is evident that we are witnessing the largest [insect] extinction event on Earth since the late Permian and Cretaceous periods,” the authors wrote.
It’s important to recognize exactly how disastrous these mass insect extinctions would be for human life – especially since the researchers say human activities are largely responsible for the escalating crisis.
“The main factor is the loss of habitat, due to agricultural practices, urbanization and deforestation,” according to the lead author of the new study, Dr. Francisco Sánchez-Bayo, of the University of Sydney. “Second is the increasing use of fertilizers and pesticides in agriculture worldwide and contamination with chemical pollutants of all kinds. Thirdly, we have biological factors, such as invasive species and pathogens; and fourthly, we have climate change, particularly in tropical areas where it is known to have a big impact.”
In particular, the authors call for changes to industrial agriculture, given its vast, and growing, impact on insect habitats.
“Unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades,” according to the paper. “The repercussions this will have for the planet’s ecosystems are catastrophic to say the least.”
There are some limitations to the study – the data is mostly from Europe and the US, and there is lack of data from tropical regions. But it certainly paints a picture of a growing global crisis with far-reaching implications, and it expands on research that until now, had mostly been limited to individual ecosystems, according to Vox.
David MacNeal, author of Bugged: The Insects Who Rule the World and the People Obsessed with Them, told National Geographic that the world’s insect population is an “invisible force working throughout the world to keep it running.”
He also cites work by entomologists saying insects contribute about $57 billion to the US economy – not including pollination.
“Most of this comes from wildlife, which insects keep going along because they are the base of the food chain for fish, birds, or mammals. Pest controlling insects add a further half billion. And there is no way to account for how much it costs to recycle a dead body or decompose plant life.”
Insects pollinate about three quarters of the world’s crops. They also provide food for small animals that form the base of many ecosystems, and help fight pest species, many of which the new report actually expects will thrive in the future. Many insect species that keep these pests in check, serve other important functions, or represent bellwethers of wider ecological crisis, are in decline. This includes insects like bees, butterflies, crickets, dung beetles, and moths.
Other insect species, not only agricultural pests, but also adaptable generalist species like houseflies and cockroaches, are likely to proliferate further under warmer conditions and in the face of expanding human-shaped environments.
In other words, we may be facing a decline among the most helpful insect species, and a rise in populations of pests.
“It should be of huge concern to all of us, for insects are at the heart of every food web, they pollinate the large majority of plant species, keep the soil healthy, recycle nutrients, control pests, and much more. Love them or loathe them, we humans cannot survive without insects,” said University of Sussex biology professor Dave Goulson, who was not involved in the study.
Other scientists have commented that the study downplays the role of climate change in favor of a focus on pesticides, according to The Guardian.
Stanford Professor Paul Ehrlich said the paper missed an opportunity to emphasize the connection between human “overpopulation and overconsumption” and the range of factors driving insect decline.
But the broader conclusions of the review have been widely embraced by scientists. And as with climate change itself, the public needs to recognize when alarm bells such as this are sounded by experts. Collective action has managed to rescue the ozone layer and a range of endangered species in recent decades. But first, the public has to come to a broad consensus that these issues represent a high priority. With insects, this may prove more challenging than with, for example, sea otters. And yet, these small and sometimes bothersome creatures form the backbone of the ecosystems we depend on for life itself.