Iain Hunter: The decline of insects is a worrying development

It’s a habit of our species to walk tall, not creep and crawl. It’s our habit to look up, not down.

We delight in our big companions on Earth, such as elephants and orcas. We give scant attention to the creepy crawlers, such as bugs — except when they bite us or fall in the soup.

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Some scientists around the globe, though, have been looking down. They believe that the worldwide decline in entomofauna (insects to us flyswatters) is a more pressing problem even than global warming.

We’ve been warned about climate change and our apparent reluctance to stop it. But though it seems relentless, it’s slow.

The decline of the insects, though, is fast. The scientists who report that decline in the journal Biological Conservation want us to realize how scary that is.

More than 40 per cent of insect species are declining. A third of them are endangered. Their total mass is falling by 2.5 per cent a year. In 100 years, they could all be gone. And then?

The birds, reptiles, amphibians and fish that eat insects will starve to death.

The large number of plants that depend on pollinators will die off.

The soil no longer will be kept healthy, nutrients no longer will be recycled, pests no longer will be controlled.

In short, the scientists warn, a “catastrophic collapse of nature’s ecosystems” is threatened.

And we know who’s at the centre of this worldwide web. Us, its destroyers and preservers.

We destroy because we can. We preserve because we must.

It won’t be easy, though. Nothing that’s worthwhile is easy.

To begin with, our planet is awakening to the dawn of the sixth mass extinction of life since its beginning.

The list of species endangered, threatened or declining includes 22 per cent of vertebrates, 26 per cent of birds, 23 per cent of amphibians, 15.4 per cent of land mammals and 19 per cent of reptiles.

But look at the insect toll: 68 per cent of caddisflies, 53 per cent of butterflies, 49 per cent of beetles and 46 per cent of bees.

Only flies have a rate of decline — 25 per cent — close to that of higher species, which might or might not concern us flyswatters.

Egyptologists, though, will be saddened to learn that of the 350,000 species of beetles vanished or vanishing, dung beetles, depicted on pharaonic tombs rolling the sun across the sky, are going fastest.

We, who walk tall with our heads close to the clouds, might be skeptical of all this. It invites denial just as climate warming does.

It’s hard to imagine how anyone can know for certain how many bugs are dying off or thriving secretly in every part of the world.

The Biological Conservation report, though, is a review of 73 scientific studies in places such as England (butterfly species fell by 58 per cent on farmed land in the nine years ending in 2009), Oklahoma (half of bumblebee species lost between 1949 and 2013), Puerto Rico (a 98 per cent decline in ground insects over 35 years) and Germany (a 75 per cent insect loss in nature preserves).

The reviewers admit big gaps in scientific knowledge about critters such as crickets, ants, shield bugs and aphids, but don’t think they could be doing better than the species that have been studied.

And who’s looking deeper into the world of bacteria, moulds and other life forms that even insects would feel beneath them?

There is, apparently, some evidence that some insect species are adapting to whatever ails them. But the adapters are far fewer than those that aren’t adapting and moving from the “endangered” to “extinct” list.

It’s up to us to prevent the collapse of our ecosystem, though no one seems to be keeping track of our decline.

The scientists say that the climate as we’re helping change it is just the fourth cause of insect-cleansing worldwide.

Habitat loss — to agriculture, urbanization and manmade corridors — is identified as the main culprit. Pollution — fertilizers, pesticides and manmade waste — is second. Third are pathogens and species introduced for human enjoyment.

So how can we rise to this sorry occasion? We could stop introducing our own species in such great numbers through population control.

We could stop consuming so much and wasting so much and become vegetarians.

At least, mindful of the bugs, we could watch where we step.

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