This past summer, “murder hornets” became high-profile pests, joining the ranks of monarch butterflies and bumblebees as insects that capture our attention. Although it’s easy to contemplate the arrival of one new (and vicious) insect, it’s much more difficult to attune to the departure of many. Insects comprise more than three-fourths of the known animal kingdom, but recent evidence suggests that their dominance is dwindling. A 2019 study, based on a review of seventy-three reports of insect populations worldwide, predicted a decline in insect biomass of 2.5 percent per year (if we think of all the insects on the globe as a singular body, that’s the rate at which that body is wasting away). If these numbers are representative of global decline, the study suggested, we’re facing a precipitous drop in biodiversity: 40 percent of all insect species could go extinct over the next few decades.
Entomologists estimate that at least two million insect species have never been named, and data on insect populations is heavily concentrated in the last three decades, so it’s difficult to measure just what we’ve lost; like so much in our shifting ecosystem, the absence of many small creatures becomes visible to us only through its effects. When we no longer find insects peppering our windshields, we begin to contemplate what it would mean to the larger ecosystem were they to disappear from their vital roles as pollinators and decomposers, as sustenance for birds and other small animals. In other words, the insects’ disappearance would trigger a domino effect of extinction.
Insects are extremely vulnerable to the growth of cities; the expansion of monoculture crops like corn and soybeans; and (especially in North America) the use of neonicotinoid pesticides, which have set off alarm bells among environmental activists. But while it’s true that the language around depleting insect populations can begin to sound apocalyptic, evidence shows that mitigation is possible. Habitat protection, restoration, changes in agricultural practices: all of these measures can slow this distressing trend—if we start to take notice.