Bye-bye, bugs. For several years, there’s been buzz about a looming insect crisis. It’s true: Insect numbers are falling. But rumors of the demise of honey, flowers, and food have been exaggerated. Still, many scientists believe a bug die-off, however small, is a big problem.
A recent study in the journal Science reports that one quarter of all land-dwelling insects have disappeared in the last 30 years. That puts the vanishing rate at just under one percent per year.
“This is not even something you would notice from year to year, because the insect population varies so much,” study author Roel van Klink tells Science News. “But after 30 years, you will have lost a quarter of your insects.”
Those findings are less dire than previous predictions. But it still adds up to something “awfully alarming,” according to van Klink.
Michigan State University butterfly expert Nick Haddad agrees. “The decline across insect orders on land is jaw-dropping,” he says.
God created insects for specific jobs. They pollinate plants, feed other creatures, control pests (insects slay insects!), and decompose trash. Haddad calls them “critical to functioning of all Earth’s ecosystems.”
Insect declines are worst in North America and in parts of Europe. But the drop appears to be leveling off in the United States in recent years. Large global losses occur near cities, where bugs are losing their food and habitat, van Klink says. He also noted that on farmland, growers remove weeds and flowers that bugs need.
Study co-author Ann Swengel is a citizen-scientist who’s tracked butterflies for more than 30 years. She recalls driving around Wisconsin a few decades ago and seeing large yellow butterflies everywhere. Now she says, “I can’t think of the last time that I’ve seen that.”
Insect losses differ from place to place and from decade to decade. Insect expert David Wagner says that means “we’re not looking for a single stressor, or we’re not looking at a global phenomenon that is stressing insects in the same way.”
The study also found that some freshwater insects—mayflies, dragonflies, and mosquitoes—are increasing faster than land bugs are disappearing. The findings show that bug populations are complex. Struggling species may live nearby thriving insects of another species.
“Each bug faces its own battle,” says Stuart Reynolds, biologist and former president of the Royal Entomologist Society. Apparently, what’s good for the gadfly may not be good for the grasshopper.