Explaining Declining Insect Populations
A first-of-its-kind analysis published in April 2020 suggests that land-dwelling insect populations are declining by 0.92% per year, with the largest declines reported in the United States (West and Midwest) and Europe (especially Germany).
“[That] may not sound like much, but in fact it means 24% fewer insects in 30 years’ time and 50% fewer over 75 years,” explains lead study author Dr. Roel Van Klink. “Insect declines happen in a quiet way and we don’t take notice from one year to the next. It’s like going back to the place where you grew up. It’s only because you haven’t been there for years that you suddenly realize how much has changed, and all too often not for the better.”
Everyone knows we need to save the bees because they pollinate crops and make honey, but the problem is so much bigger than that. Did you know that up to 88% of the world’s plants are pollinated by beetles - not bees?
Did you know that a full third of all food and beverages produced rely on pollinators?
Insects also help facilitate crop growth by aerating the soil, recycling plant material, eating bugs that damage crops, and speeding the decay of dead leaves, animals, and waste.
“Without our insect recyclers, we would drown in our own natural wastes,” notes Breda Pest Management.
Insects also represent a major food source for birds, fish, and amphibians. Without bugs, we would see start to see these species (and those that eat them) disappear.
Spiders are among the most beneficial “pest” because they eat mosquitoes that carry disease. Spiders also eat moths, which can damage fabric, and other spiders, some of which carry a deadly bite.
Insects are also useful in the medical field. Currently, researchers are studying the venom of a Brazilian wasp as a potential cancer treatment.
The 2020 analysis I mentioned earlier supports a prominent study published in Germany in 2017. The earlier study suggests that the number of flying insects in Western Germany has declined by more than 75% over the past three decades. They call it the windshield phenomenon.
This shocking decline was consistent regardless of habitat, land use, and weather; it was even present in nature reserves meant to protect insects and other species.
The modern agricultural landscape is very hostile for insects, says Dr. Hans de Kroon of Radboud University.“It’s a desert, if not worse.”
On a brighter note, the 2020 analysis found that freshwater insects (such as midges and mayflies) showed an average annual increase of 1.08% - possibly due to clean water legislation.
Freshwater insects represent less than 10% of the total population, notes Van Klink. “The total number of freshwater insects will never be able to compensate for the terrestrial insects.
Nonetheless, Van Klink and his team are hopeful that legislation will be put in place to help land-dwelling insects recover.
“Insect populations are like logs of wood that are pushed under water. They want to come up, while we keep pushing them further down. But we can reduce the pressure so they can rise again. The freshwater insects have shown us this is possible,” says Van Klink. “The nice thing about insects is that most have incredibly large numbers of offspring, so if you change the habitat in the right way we will see them recover really fast.”