Thinking Beyond Science

Without insects, the world’s wealthy could perhaps deploy the resources required to indefinitely stretch out a semblance of the status quo. But for the majority of humanity, the loss of insects would be an agonizing ordeal eclipsing any war and even rivaling the looming ravages of climate breakdown.

“Most of life on Earth would disappear if we didn’t have insects, and if there were any humans left they wouldn’t be having much fun,” says Dave Goulson, professor of biology at the University of Sussex.

“I think it is stretching it a bit to suppose that all humans would be dead in a few months, but there is no doubt that millions of us would be starving.”

Insects have been involved in an intricate dance with almost every aspect of the terrestrial environment for millions of years, forming an underappreciated foundation for human civilization itself. They multiply our food, act as food themselves for the other living creatures around us, rid us of the foulest waste, eliminate unwanted pests, and, crucially, nourish the soil, the Is-centimeter (6-inch) patina wrapped around our globe that sustains all of humanity.

The weight of this dependence has failed to spark much devotion for insects. Three out of every four known animal species on Earth are insects and yet, within their massed ranks, only butterflies are considered with anything close to affection. Wasps are a baleful summertime menace, ants an invading army fought with toxic sprays in the kitchen, and mosquitoes everything from irritating nuisance to lethal threat. Most of the other I million species of identified insects are considered by many people, if they are ever considered at all, to be either quirkily obscure or pointless.

Bumblebees have been found at 5,500 meters (18,000 feet) above sea level, a height just shy of Mount Kilimanjaro’s summit. Dragonflies can steadily hover in fierce winds that would down even the most advanced helicopter. A horned dung beetle is so strong that if it were a human, it would be able to hold aloft six double-decker buses.

You could say that the insect family embraces the bizarre. Insects breathe in and out via holes called spiracles in their exoskeletons and see via intricate compound eyes, allowing creatures such as dragonflies to have a 360-degree field of vision. Stingless bees feed on human sweat and tears, a species of butterfly has an eye on its penis, and some aphids can produce young that already contain their own babies-—effectively they give birth to their own grandchildren. Insect populations are normally fairly elastic, too, able to navigate huge spikes and troughs when dealing with changeable conditions. But while insects are legion, that doesn’t mean that they are utterly disposable —they all play some sort of role in pollination, or in decomposition, or in the food chain.

Start yanking enormous numbers of insects out from the environment and the whole web of life, including humanity, is thrown off-kilter. The collapse can fold in on itself, too-around 10 percent of insects are parasites, often of other insects. If certain wasps can’t find caterpillars to act as their slave puppets and egg hosts, or if certain flies can’t hijack an ant’s brain and then decapitate it, they, too, are under threat. This dangerous scenario is now coming into focus as scientists have started to piece together the puzzle of insect life. A warning shot was fired in 2014 with a compendium of available research that found that a third of invertebrate species documented by the International Union for Conservation of Nature (IUCN) are in decline, with these population decreases amounting to 45 percent globally over the past four decades. The losses were nearly double that of vertebrates.

Pull different levers and you set in motion a cascade of conse-quences. Across the broad family of arthropods there are creatures such as wood lice, millipedes, and springtails that perform tasks such as chewing up dead plant matter, grazing on fungi off root surfaces, and releasing nutrients for plant growth. Waste-eating insects such as dung beetles unlock nutrients from feces, rotting plants, and corpses that would otherwise stagnate. Other species like ladybugs and lacewings prey on crop pests such as aphids. The engineering aptitude of termites—their tunneling cracks open hard ground, helping it absorb water and nutrients—can help turn barren land into fertile fields.

If whole species of these specialists are lost, then vital ecosystem functions, such as maintaining soil and plant health, are diminished.

But certain animals themselves feed on these insects in huge volumes; a blue tit parent, for example, will need to cram up to a hundred caterpillars a day down the gullet of a single chick. The loss of a few niche species won’t bother most birds if they are able to dine on other insects that boast strong populations. A major crash in overall insect numbers, though, is a different matter. We can marvel at the individual qualities of insects, but their role in the ecosystem is almost always executed in massed numbers. It’s not just about the breadth of the insect universe, it’s the depth, too.

Source : The Insect Crisis: The Fall of the Tiny Empires That Run the World by Oliver Milman

Goodreads : https://www.goodreads.com/book/show/58100655-the-insect-crisis