By almost any measure, insects are by far the most numerous animals on the planet. Scientists estimate there could be anywhere between five and 30 million species of insects on Earth, one million of which have been formally named and described. In comparison, there are a paltry 6495 known species of mammals and an estimated 18,000 species of birds.

Insects are also mind-bogglingly numerous. For example, there are an estimated 10,000,000,000,000,000 (10 quadrillion) individual ants alive at any one time. The sheer number of insects on Earth is so jaw-droppingly high that most people – including some scientists – simply assumed that insect populations could not possibly be in trouble.

But we may have been very, very wrong. Recent studies in the Americas and Europe have uncovered evidence of worrying declines in insect populations. In one concerning example, 75 per cent of insect biomass vanished within 26 years. Other studies have reported decreases in protected areas where insect populations were expected to be thriving.

In retrospect, insect falloffs are not particularly surprising. Human actions over the past few centuries have led to the catastrophic decline of birds, mammals, fish and reptiles. There’s little reason to believe that insects will have fared better than other animal groups. For all their seeming toughness, insects are just as susceptible to habitat loss, climate change, pollution and impacts from invasive species.

Insect apocalypse?

The fact that some insects are in decline is undisputable. But are we really on the edge of an imminent ‘insect apocalypse’?

The answer is complicated. The sheer diversity of insects means it is impossible to make generalisations – while some species are undoubtedly in decline, others are thriving. A recent review of scientific studies concluded that, on average, populations of land-living insects are waning by about eight per cent every decade. Paradoxically, insects with an aquatic life stage such as dragonflies and damselflies are actually increasing – possibly as a result of improvements in water quality.

The bottom line is that insects are diverse. There are many species, each with their own specific set of needs. And how a species fares over the next decades will depend on the details of its biology and on the specific threats it faces.

Ideally, scientists would be able to identify species most at risk of extinction; these could then be prioritised for protection. Unfortunately, we know almost nothing about the biology of the vast majority of insect species. In most cases, we don’t know how many there are, how many there were in the past, what threats they face or what they need to survive. Without this basic information, it’s almost impossible to say with any certainty whether insect populations are rising, falling or staying the same.

In Australia, the lack of information about insect ecology is compounded by the sheer number of unique species that call our continent home. It’s estimated that we have identified and named less than 20 per cent of Australian insect species. How can we protect an animal if we haven’t yet given it a name? The grim reality is that we are almost certainly losing species before we even know they exist.

It’s like burning a library without reading the books. We will never know what we have lost.

The importance of insects

While claims of large-scale insect catastrophes are not yet supported by data, it’s clear that at least some insect species are in trouble. It’s a funny quirk of human psychology to think that only massive, global declines are worth our attention. Insects play so many key roles within our ecosystems, that plunges in even a few species should be cause for concern.

Insects are powerhouse pollinators; 90 per cent of flowering plants are pollinated by insects including many important – and delicious – crop plants like strawberries, macadamias, watermelons and avocados. We have insects to thank for pollinating both coffee and chocolate, two things many of us could not imagine living without.

Without insects, waste would not be recycled back into the ecosystem to nourish the next generation of plants. Insects are also the main food source for countless species of birds, fish, reptiles and mammals.

Insects are carrying the whole world on their six tiny shoulders. To quote famous entomologist EO Wilson, they are “the little things that run the world.”

Public image problem

Unfortunately, the plight of endangered insects rarely attracts much public attention unless it’s framed as an ‘insect apocalypse.’ Despite the important role they play in our ecosystems, insects are at best ignored, and at worst, actively disliked.

We tend to notice insects only when they are causing a problem: a buzzing mosquito in the bedroom, a large cockroach on our toothbrush, a sting from an angry wasp. But all the while, most insects are quietly going about their business, unnoticed by the majority of people. These insects are our pest controllers, our pollinators and our waste managers. Many other species are functionally neutral, neither hurting nor harming humanity. And yet, the bad impression left by the minority of insect species is enough to sour public opinion.

Even biologists are guilty of vilifying insects. In the 1990s, conservation biologists were feverishly working to save the California condor and the black-footed ferret, two iconic American species on the brink of extinction. As part of the captive breeding program, ferrets and condors were treated with an insecticide aimed at killing the tiny parasitic lice that lived in their fur and feathers. The program was successful and both the condor and the ferret were saved. But the insecticide treatments drove the two species of louse into extinction. Neither louse species was ever shown to be harmful; much like human head lice, they were probably little more than an annoyance.

The sad story of the extinct lice highlights the difficult ethical issues that arise in insect conservation. How do we go about assigning value to the life of a species? Are furry mammals intrinsically more worth saving than are insects? It’s a thorny issue with no easy answers. But it’s a discussion we need to have, because if we cannot learn to value and love insects, then we almost certainly will not fight to save them. And that would be a tragedy.

Tiny wonders

As an entomologist, I spend a lot of my time looking closely at insects. I can see why people find them unattractive: they often look like tiny aliens. They have an unreasonable number of legs and they move in unpredictable and unnerving ways. But up close, insects can be astonishingly beautiful.

To appreciate the strange beauty of insects, you need to see them on their scale. Take the little Chrysis wasp. Up close, they look like tiny colourful disco balls, their bodies shimmering in jewel tones of iridescent emerald and purple. Or the bee-fly, a fluffy flying puffball with delicate legs and big doleful eyes.

Other insects are notable not because they are cute or beautiful, but because of their astonishing abilities. The tiger beetle, for example, runs so quickly that its eyes cannot collect enough light to form an image ‑ it literally runs so fast it goes partially blind. One of the longest insects, Chan’s megastick is a stick insect as long as an adult human forearm, while the smallest insect – in fact, the smallest animal of any kind – is the tiny fairy wasp, no bigger than the full stop at the end of this sentence.

When you take the time to get to know them, insects are every bit as amazing and beautiful as larger animals.

Protecting the little things that run the world

As a scientist, I wish we had better information about the health of our insect populations. But I worry that if we wait until data on insect slumps is crystal clear, it will likely be too late to avert a tragedy.

Fortunately, there are actions we can take now, with little risk, that can help protect our insect biodiversity. At a high level, moves like protecting our bushland, increasing green spaces in cities, acting on climate change, and lowering soil and water pollution will help to conserve insects. These actions will also benefit other animals like mammals, birds, fish and reptiles, as well as improving human health and wellbeing.

At home, we can avoid the use of broad-spectrum insecticides in our houses and gardens. Broad spectrum insecticides often cause more harm than good because they kill off the predatory insects and spiders that might otherwise keep our pest problems under control. Simple techniques like hand removing caterpillars from plants can be effective ways to minimise insecticide use.

Planting flowers is another simple practice that can have a strong impact on insect diversity. Many insects love a sip of nectar or a feed of nutritious pollen, so planting a variety of flowers ‑ particularly native ones ‑ can help support insect biodiversity. Flowers can also increase the number of predatory insects in an area, resulting in better pest control.

In the end, perhaps the most important thing we can do is to start appreciating insects for the wonderous, beautiful and important animals that they are. Next time you go outside, take the time to really look at nature’s tiny wonders. Watch them as they go about their business. Take the time to identify them and learn about their ecology.

Because learning to love the little critters that run the world is the first step towards conserving our precious insect biodiversity.