The Hidden Decline Beneath Our Feet

On a recent trip to research insect populations, I visited a small sliver of the Chihuahua desert that runs through the extreme southeast corner of Arizona. While hiking through the flat expanse, I encountered hundreds of eager hover flies.  I say eager, because the flies followed and buzzed around me relentlessly.  While I couldn’t identify any single individual fly, I am certain that a few of them followed me for more than half a mile as I trekked through the dry, rock strewn, dusty desert.  I am not a dancer, but all of the swatting, arm waving, and stumbling probably made me look like I move like Mic Jagger.  Relief came when wind from an approaching thunderstorm forced the flies to land or be blown away.

Of course, the flies were after me because I was a source of water and salt in the middle of a desert.  The flies need both to survive and reproduce, and with a life span measured in weeks, the flies had no time for politeness.  Their tiny biological clocks were ticking.   They were in their golden days, having already lived most of their young lives as larvae and then metamorphosing into the annoying fly stage that zipped just a little too close to my ear canals.  For me it was irritating, but for the swarming flies, it was all-or-nothing; do or die.

What struck me later was not how many flies there were, but how differently most people would interpret the experience. Standing among hundreds of insects, I was witnessing an important part of the ecosystem. Many people would have seen only a nuisance.

That difference in perception lies at the heart of one of the most important questions in ecology.

How do we recognize the loss of something we rarely notice in the first place?

The Creatures We Overlook

Large mammals capture our attention effortlessly.

People travel thousands of miles to see polar bears, elephants, jaguars, or whales. Conservation campaigns celebrate charismatic species because they inspire emotion and public support.

Insects rarely receive the same treatment.

When insects appear in news stories, they are often described as pests, invaders, or disease carriers. Even the language we use reflects this bias. A group of buffalo is a herd. A group of insects is a swarm.

One sounds majestic.

The other sounds threatening.

Yet insects perform many of the ecological functions that make life possible. They pollinate plants, recycle nutrients, aerate soil, control pests, and serve as food for birds, bats, fish, reptiles, and countless other animals.

Most ecosystems depend on insects.

Most people rarely think about them.

The Ecology We Stop Seeing

One of the challenges of studying insects is that abundance can create an illusion of permanence.

When organisms appear everywhere, it becomes difficult to imagine they could disappear.

History suggests otherwise.

Few examples illustrate this better than the Rocky Mountain locust. During the nineteenth century, enormous swarms darkened skies across the American West. Settlers described clouds of insects so dense that trees, fences, buildings, and fields became completely covered.

At the time, few people believed such vast populations could ever vanish.

Yet they did.

The Rocky Mountain locust is now extinct.

Its disappearance reminds us that even extraordinarily abundant species can be vulnerable when critical habitats are altered.

How Do We Measure What We Rarely Notice?

In recent years, scientists have raised concerns about declining insect populations in parts of the world.

One influential study reported substantial declines in insect biomass collected from traps in European nature reserves over several decades. More recently, researchers analyzing long-term surveys from thousands of sites found evidence of declines in many terrestrial insect groups, although some freshwater insects appeared to be increasing.

These findings generated headlines about an “insect apocalypse.”

The reality is more complicated.

Unlike birds or large mammals, many insects have never been monitored consistently. Population sizes often fluctuate dramatically from year to year. Some species experience natural cycles that may last years or even decades. Many regions of the world lack long-term surveys altogether.

For countless insect species, we simply do not know whether populations are increasing, decreasing, or remaining stable.

This uncertainty reveals another hidden aspect of ecology.

Sometimes the greatest challenge is not understanding why something is disappearing.

It is realizing that we never paid enough attention to measure it in the first place.

What Happens When Small Things Matter

When people think about biodiversity loss, they often focus on species themselves.

Ecologists frequently think about processes.

Pollination.

Decomposition.

Nutrient cycling.

Seed dispersal.

Food webs.

Much of the work that keeps ecosystems functioning happens quietly and largely out of sight. Insects are responsible for many of these processes.

When insect populations change, the effects can ripple outward through entire ecosystems. Birds may lose food sources. Plants may receive fewer pollinators. Soil communities may function differently. The consequences are often subtle at first, making them difficult to recognize until much later.

The Hidden World Around Us

The hoverflies in the Arizona desert reminded me of something easy to forget.

Nature is filled with organisms that exist below the threshold of our attention.

We notice insects when they sting, bite, or become a nuisance. We rarely notice them when they pollinate flowers, recycle nutrients, or support entire food webs.

Yet these overlooked organisms help shape the ecosystems we depend upon every day.

The question is not simply whether insect populations are declining.

The deeper question is whether we are paying enough attention to know.

Because by the time we notice the absence of something we rarely saw in the first place, part of the story may already be gone.