Your Land & Water for September 2025
- jhansen49
- Sep 14
- 4 min read
What's in this issue? The buzzing sound of insects is divisive to many people but is incredibly important for our ecosystem. The absence of our six legged counterparts would (and currently is) have detrimental effects for us and all other organisms on our planet.
Where Have All the Insects Gone?
By Suzanne McCarthy
Insects — the tiny powerhouses that pollinate crops, recycle nutrients, and feed countless species — are vanishing at breakneck speed.
Germany: Flying insect biomass down 76% in 27 years — 82% in midsummer.
Puerto Rico: Rainforest arthropods down 78–98% over 36 years.
Worldwide: 40% of species in decline, one-third threatened; biomass shrinking ~2.5% a year.
USA: Butterflies down 22% since 2000, with some species collapsing by over 50%.
What are the causes of this decline? Habitat loss, pesticides, climate change, light pollution, and invasive species are the principal factors, and it appears that the mix of those conditions is responsible, rather than just one. Another part of the problem is the lack of good data on insect numbers, especially in the tropics.
INSECT DECLINE = BIRD DECLINE = BIODIVERSITY DECLINE =
DANGER FOR HUMANS
Birds – Many bird species, especially insectivores like swallows, swifts, flycatchers, warblers, and nightjars, are heavily dependent on insect populations for food. It’s estimated that it takes between 350 and 570 caterpillars per day for Chickadee parents to feed their young, for example. When insect numbers fall, birds often follow the same downward trend. Most birds, even those that aren’t aerial insectivores suffer when insect numbers decline and when insect cycles shift.
Black-throated Blue Warbler (Setophaga caerulescens)
o Times its breeding to coincide with
caterpillar peaks.
o Studies show mismatches: warmer springs
make caterpillars emerge earlier, while the
warblers’ migration timing hasn’t shifted,
enough so chicks miss the food peak.
Flycatchers (like Eastern Phoebe or
Least Flycatcher)
o Depend on bursts of insect activity
in spring.
o Declines in insect-rich habitats
(like wetlands and meadows) have
hit them hard.
Biodiversity – “The rapid declines in birds signal the intensifying stressors that wildlife
and people alike are experiencing around the world because of habitat loss, environmental degradation, and extreme weather events,” said Dr. Amanda Rodewald,
faculty director of the Cornell Lab of Ornithology’s Center for Avian Population Studies.
“When we see declines like those outlined in the report [the 2025 U.S. State of the Birds], we need to remember that if conditions are not healthy for birds, they’re unlikely to be healthy for us.”
Danger for humans – Insects pollinate crops, recycle nutrients, control pest populations,
and form the foundation of food chains. Without them:
Pollination: Declines could threaten the production of fruits, vegetables, and nuts,
undermining global food security.
Soil health: Could deteriorate without decomposers breaking down organic matter.
Birds, amphibians, and mammals: Animals that feed on insects could suffer cascading population declines.
Bird declines: Consumption of pest insects would drop, threatening human crops.
As E. O. Wilson, the great sociobiologist, said, “If all mankind were to disappear, the world
would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos.”
In short, a collapse in insect populations would not be a quiet tragedy — it would be a profound ecological shock.
SOLUTIONS:
Reduce pesticide use and shift toward integrated pest management.
Restore habitats through native plant landscaping, wildflower meadows, and pollinator corridors. Reduce the amount of lawn.
Support organic and regenerative agriculture that prioritizes biodiversity.
Mitigate climate change by cutting greenhouse gas emissions.
Rethink urban spaces with insect-friendly green roofs, parks, and dark-sky lighting policies.
Support broadening and standardizing long-term monitoring, especially across underrepresented regions and tropical ecosystems.
Promote engaging the public through citizen science, which can enhance data collection and awareness, but must be paired with robust scientific oversight.
Although action is needed on a global scale, we can improve conditions on a much smaller, more personal level. One program that is easy to follow and adopt is University of Delaware entomologist Doug Tallamy’s “Homegrown National Park” (https://homegrownnationalpark.org) which proposes the following: “...what if each American
landowner converted half of his or her yard to productive native plant communities? Even moderate success could collectively restore some semblance of ecosystem function to more than 20 million acres of what is now ecological wasteland.”
The program and Tallamy’s fascinating books give simple advice on increasing insect diversity by reducing your lawn, using keystone native plants in your landscape, leaving leaf litter around plants for insect development, eliminating pesticide use, and changing your outdoor lighting to promote dark skies. A video of his talk to the Native Plant Society of New Jersey is definitely worth watching. It’s at https://www.youtube.com/watch?v=8EZq9kY6ovU.
Sources:
David L Wagner, Eliza M Grames, Matthew L Forister, May R Berenbaum, David Stopak. Insect decline in the Anthropocene: Death by a thousand cuts. Proc Natl Acad Sci U S A. 2021 Jan 11; 118(2).
North American Bird Conservation Initiative. 2025. The State of the Birds, United States of America, 2025. StateoftheBirds.org
Saravia, Christian. Insects Matter. Why Are We Wiping Them Out? May 20, 2025. Earth.org, www.earth.org