Insects have a reputation for “bugging” us humans with their bites, stings and incessant buzzing. While we may wish they would just go away, researchers have concerns about declining “bug biomass” and how it could impact us.
We know a lot about dinosaurs and the earth they lived in from studying fossils. Insects have been around even longer—showing up with land plants and outlasting dinosaurs through five mass extinctions.
“People who look at the diversity of life on Earth estimate that only about 2% of the species who ever lived with that ever lived are alive now. Probably the largest number that were ever alive at one time, because it's been expanding continuously for the past 66 million years since the last major extinction took place,” said Peter Raven, president emeritus of the Missouri Botanical Garden and a professor emeritus of botany at Washington University.
Raven said researchers began studying insect species— biodiversity—in the 1980s and now estimate there are many as 9 million species.
Researchers also study insect populations—biomass—and report declining species and populations for moths, butterflies, bees, hoverflies—as much as 1-2% per year.
With such a long record and so many species of insects, why be concerned about declining insect populations now?
Raven said humans are newcomers, arriving in Africa only about 300 thousand years ago. And the things that came with humans, like agriculture and the intensification of climate change place crucial ecosystems at risk.
“The population of the whole world at the time they started growing crops in the Middle East, about 11,000 years ago [was] about one million,” Raven said. “By the Roman Empire, the time of Christ, there were two-three hundred million people. We reached 7.8 billion that we have now, projected to grow to 9.9 billion in 30 years.”
According to Raven, 11% of land is now in agriculture and 30% in grazing, with most of earth’s landscape impacted by our development– numbers he said must change to sustain us.
“What individuals do, especially in very rich countries will help a lot. I do find hope in morality, because there are moral people. One of the great things you can do is teach everyone to be as international as you possibly can,” Raven said.
Insect declines are already beginning to affect the ecosystems they inhabit. Scott Black, the executive director of the Xerces Society for Invertebrate Conservation, said insects play an important role in ecosystems, pollinating crops, decomposing leaves and feeding everything from songbirds to fish, which feed larger animals.
“The two main food sources for grizzly bears are salmon, which need insects to get to the ocean, and berries, which need insects to pollinate them. So, even on up to grizzly bears, they are really relying on this base of the food chain,” Black said.
While declines aren’t often noticeable short-term, long-term declines are striking.
“In the West, monarchs used to travel all the way from Utah, back to California. In the 80's, we had over four million monarchs at these overwintering sites. This year, we had 1,914 monarchs,” Black explained. “Another species found in Utah is the western bumblebee. It's gone from the entire West Coast. You're lucky you still have it in Utah.”
So what can humans do to slow insect decline? A recent list published by Black and his colleagues provides a starting point.
For example, Black suggested buying insect-friendly products and supporting insect-friendly habitat initiatives, such as organic farming. In Cache Valley, organic agriculture is on the rise, thanks to sustainable farming ambassadors and insect-friendly initiatives like Bee Better Certified.
Similarly, Bee City and Bee Campus USA are programs focused on creating insect habitat. Last year, the University of Utah became a certified Bee Campus.
The quest for the perfect lawn is another source of insect declines.
“The best data we have shows that we've got 40 million acres of lawn and lawn provides nothing for almost any insect. If everybody took out 10% of their lawn, that'd be four million more acres of habitat for these animals,” Black said.
Even small actions are helpful, and Black said if friends or neighbors take the steps together, they become even more powerful.
To learn more about insect declines and other ways to help insects, visit Xerces.org.