Is an ‘Insect Apocalypse’ Happening? How Would We Know?
Brian Lovett at University of Maryland | 4/29/2019 | Via TheConversation.com
Insects scuttle, chew and fly through the world around us. Humans rely on them to pollinate plants, prey on insects that we don’t get along with, and to be movers and shakers for Earth’s ecosystems. It’s hard to imagine a world without insects.
That’s why news reports in recent months warning of an “insect apocalypse” sparked widespread alarm. These articles, which were based on long-term insect collections and a review of past studies, suggested that people alive today will witness the indiscriminate extinction of insect-kind.
I study fungi that can be used to control harmful insects, such as pests that damage crops and mosquitoes that transmit malaria. In my world, reports of mass insect die-offs are big news. But while there clearly is reason to be concerned about certain insects, such as the endangered rusty patched bumble bee or the American burying beetle, in my view it isn’t yet possible to predict a looming insect apocalypse.
More than 1 million insects have been discovered and named, but many millions have yet to be described. It’s undeniable that Earth is becoming increasingly inhospitable to some insects – but nightmarish conditions for one may be heaven to another.
Put another way, there is no perfect environment for all insects. And human impacts on the environment, like climate change and land development, very well may hurt beneficial insects and help harmful ones.
Around the world, entomologists are looking wistfully into empty nets, and car owners are increasingly unsettled by their pristine windshields. It does not take decades of data collection and a degree to notice that in a human lifetime, our teeming world teems less.
The first study to set off alarms was published in 2017 by entomologists in Germany, who reported that over 27 years the biomass of flying insects in their traps had declined by 75%.Another study from the Luquillo Long Term Ecological Research program site in the Puerto Rican rainforest reproduced an insect survey from the 1970s. It found that the biomass of arthropods – a large group of organisms that includes insects – had declined 10- to 60-fold in that time, and that lizards, frogs and birds that ate arthropods had also declined.
Underscoring this theme, in April 2019 two scholars published a review that synthesized over 70 reports of insect decline from around the world, and predicted mass insect extinctions within a human lifetime. They took a alarmist tone, and have been widely criticized for exaggerating their conclusions and selecting studies to review with the word “decline.”
Nonetheless, these researchers had no trouble finding studies to include in their review. Many scientists are currently analyzing the roles that climate change, land use, chemical pesticides and other factors have played in reported declines in many insect species.