Where have all the insects gone?

For some people, insects can be pretty scary. The mere thought of March flies and mosquitoes makes them itchy. Gardeners, on the other hand, relish beneficial insects such as dragonflies, hover flies and ladybirds. Irrespective of your predilections, nature depends upon 900,000 different kinds of wriggling, buzzing, floating, spinning, swimming and soaring invertebrates in order to function.

Alas, just like our planet’s climate, the insects, too, are in terrible trouble.

During the summer, no matter where you live in the world, whether you are bicycling, driving an automobile or motorcycle, the absence of insects is apparent. There are far fewer smashed bugs on sunglasses, windshields and helmet visors. In some locations, eerily, there are almost none.

Why are insects so important? 

As vital members of the Earth’s ecosystems, insects perform many important functions. For example, insects aerate the soil, pollinate blossoms, self-regulate themselves as well as protecting some plants.

Many insects, especially beetles, are scavengers. They feast upon dead animals and help begin the decomposition process of fallen trees. They also recycle nutrients. Along with many other insects and soil flora, beetles help create rich humus, enabling plants to grow. Burrowing bugs, such as ants, beetles and others, excavate tunnels that provide channels for oxygen and water thereby sustaining plant growth. Bees, hover flies, wasps, butterflies, ants and many others pollinate 330,000 kinds of flowering plants. Insects fertilise the soil with nutrients via their droppings. Then there’s the smorgasbord of food insects provide for amphibians, birds, mammals, fish and reptiles. Insects comprise two thirds of all terrestrial species on Earth. Life on this planet cannot exist without the breathtaking diversity and bulk of the astonishing insects.

Hover flies are heroes. Some 6000 species of these splendid beneficial insects make them the second most important plant pollinators next to 20,000 kinds of bees. Large bulbous eyes, short antennae and a single pair of wings easily identify the hover fly. These beauties dart to and fro and hover like miniature spy helicopters while feeding on nectar and pollen. Many of the more furtive species employ a black and yellow striped camouflage, mimicking the colouration of bees and wasps to foil predators. Hover fly larvae are voracious consumers of aphids and scale. They are wonderful garden custodians. The two most common Australian species of hover flies are Melangyna viridiceps and Simosyrphus grandicornis. Hover fly eggs require still water to develop.

Unfortunately, among the 120,000 or so species of flies on the planet, sophisticated long-lasting poisons have trounced global populations.

Here in Australia

The Australian Alps are a heavenly slice of unique fauna and flora, especially adapted to a winter snowfall environment that is effectively regulated by the enigmatic root systems of the incomparable cold-tolerant snow gums. But over the previous decade, bushfires have repeatedly scorched the Alps, while heatwaves and droughts have killed a million gums. As a result, billions of summertime High Country ambassadors, the migrating bogong moths, are gone. This, in turn, has tightened the noose on the critically endangered mountain pygmy possums, which depend upon the moths as their food source after emerging from hibernation in September. No moths. No food. No pygmy possum offspring.

The grandfather of High Country ecology, Dr Ken Green, has been monitoring bogong moths for almost half a century. He’s apprehensive because, “Last summer numbers were atrocious. It was not just really bad, it was the worst I had ever seen. Now this year it’s got even worse.”

Alas, the bogong moth is just one stark example of the impact global warming is having on insects all over Australia and the world.

Which insects are most affected?

The most glaring trend amid the missing insects is the direct consequence of poisons on the pollinators (bees, hover flies, butterflies) and the fresh water insects (beetles, caddisflies, dragonflies, mayflies, stoneflies). No pollinators means that we could lose 75 per cent of our food. The diversified water-dependent insects are both predators and prey, a good barometer of fresh water health while being vital food for fish, reptiles, amphibians, bats and others.

That such large diverse groups of insects are all declining, as the use of nerve poisons is skyrocketing, is a clear signal of far-reaching chemical toxicity stoking the accelerating Earth’s sixth mass extinction.

For every problem there’s at least three solutions. Scientists understand the causes of the insect decline and how to slow it down, so there is hope.

While penning this story, a billion painted lady butterflies danced across southern California’s sky – a rare pageantry and an encouraging spectacle after a wet winter. We must all become caretakers, consuming and wasting much less in order for nature to survive the forthcoming decades.

Action you can take

The destruction of habitat and insects is devastating, but there is so much individuals can do stem the tide and give insects a chance. Here are some ideas to get you started:

• Become a citizen scientist and join community monitoring groups such as Atlas of Living Australia (ala.org.au/citizen-science-central) and Project Finder.

• Join an environment group and work to convince authorities and governments of the urgent action needed, such as stopping land clearing and better chemical regulations.

• Always provide wild spaces and nesting sites for insects and wildlife in your garden: ponds for water insects, bee houses for native and honey bees, and watering stations. In fact, you could even keep your own bees!

• Plant your garden with nectar-rich, insect attracting flowers, plants and trees.

• Only spray pest insects with organic sprays as a last resort, and even then, when beneficial insects are not present.