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How the smallest bugs make the biggest impact

The Importance of Tiny Insects

A recent visit to a community allotment, brim-full with healthy, succulent vegetables and fruit glistening in the sunshine, brought into sharp focus the crucial part played by insects in bountiful food production. The ripe and plentiful beans, artichokes, brassicas, onions, lettuces and the rest, their leaves glossy and stems heavy with produce, were surrounded by and intermingled with deliberately planted flowers whose brilliant colour and scent had attracted thousands of tiny insects who flitted from plant to plant collecting nectar but also, crucially, pollinating plants and eradicating pests, thereby facilitating the abundant crop.

The truth is, about three quarters of all flowering plants and the crops that produce more than one third of the world’s food supply are pollinated by insects. Tiny insects may disturb your picnic, bite or give you the creeps, but they are quite simply the difference between life on Earth or extinction, because they are not just the pollinators without which crops would fail, they return essential nutrients to the soil from dead matter, and also serve as the base of the food chain, being eaten by everything from birds to small mammals to fish. So, it’s not unreasonable to say that if they decline, every living thing on the planet will too. Dino Martins, an entomologist at Kenya’s Mpala Research Centre, couldn’t be plainer:

“No insects equals no food, [which] equals no people.”

Now that’s serious!

“There is reason to worry,” adds its lead author Francisco Sánchez-Bayo, a researcher at the University of Sydney in Australia. “If we don't stop it [insect decline], entire ecosystems will collapse due to starvation.”

But the terrifying part is that insects ARE declining! Fast. In February 2019, National Geographic reported how a study published recently in Biological Conservation suggested that:

  • 40% of all insect species are in decline and could die out in the coming decades;

  • that half of the moth and butterfly species are in decline, one third of them threatened with extinction;

  • that nearly half of surveyed bees and ants are threatened;

  • that caddisflies are among the worst off with 63% species threatened, due in part to their eggs being laid in water, making them vulnerable to pollution and development.

And these are not just one-off findings: in October 2017, a group of European researchers found that the biomass of flying insects in 63 protected areas of Germany had declined by more than 75% in just 27 years; more recently, in Puerto Rico, it was found that the biomass of insects had fallen between 10 and 60-fold since the 1970s. So, this is a global problem.

What’s clear is that the negative effects of reduced numbers of insects are being felt around us already: in Britain, the grey partridge, whose chicks fed on the insects once prolific in cornfields, and the spotted flycatcher which feeds on aerial insects, have both declined by more than 95%. The red-backed shrike, which feeds on big beetles, became extinct in Britain in the 1990s.

Help! What’s caused the decline? Man, Man, Man, of course!

  • Herbicides, insecticides, fungicides and pesticides are in part to blame — insecticides hurt non-target insects and pesticides are thought to have caused one eighth of the insect decline.

  • Then on top, habitat disturbances caused by humans, such as deforestation, the decline of hedgerows, the demise of small family farms which tended to focus on fields for pasture, the obliteration of meadows and wetlands erased for development have all played their part in the destruction.

  • So, too, has climate change: extremes of weather such as droughts and flooding have all had impact on insect populations.

  • Pollutants share the blame too: for example, research shows that plants exposed to high levels of nitrogen dioxide, similar to levels recorded in major urban centres, are able to better defend themselves against herbivorous insects.

Here’s the bottom line: if we are to save the food all animals depend on, if we are to preserve the continuation of our very own species, we must take action to encourage the survival of some of the tiniest species in our world first. And that action has to be now!

Check out our next blog to discover the changes we have to make…

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