A bugging apocalypse threat

The world is now seeing a ‘catastrophic collapse’ of insects, warns study.

NEARLY half of all insect species worldwide are in rapid decline and a third could disappear altogether, according to a study warning of dire consequences for crop pollination and natural food chains.

“Unless we change our way of producing food, insects as a whole will go down the path of extinction in a few decades,” concluded the peer-reviewed study, which is set for publication in April.

The recent decline in bugs that fly, crawl, burrow and skitter across still water is part of a gathering “mass extinction,” only the sixth in the last half-billion years.

“We are witnessing the largest extinction event on Earth since the late Permian and Cretaceous periods,” the authors noted.

The Permian end-game 252 million years ago snuffed out more than 90% of the planet’s life forms, while the abrupt finale of the Cretaceous 66 million years ago saw the demise of land dinosaurs.

“We estimate the current proportion of insect species in decline – 41% – to be twice as high as that of vertebrates,” or animals with a backbone, Francisco Sanchez-Bayo of the University of Sydney and Kris Wyckhuys of the University of Queensland in Australia reported.

“At present, a third of all insect species are threatened with extinction.”

An additional one percent join their ranks every year, they estimated. Insect biomass – sheer collective weight – is declining annually by about 2.5% worldwide.

The catastrophic decline of insects would pose an existential threat to other animals, insects being at the bottom of the chain and the primary food source. Since 1970, 60% of mammals, birds, fish and reptiles have been wiped out.

“Only decisive action can avert a catastrophic collapse of nature’s ecosystems,” the authors cautioned.

The study, to be published in the journal Biological Conservation, pulled together data from more than 70 datasets from across the globe, some dating back more than a century.

By a large margin, habitat change – deforestation, urbanisation, conversion to farmland – emerged as the biggest cause of insect decline and extinction threat.

Next was pollution and the widespread use of pesticides in commercial agriculture.

The recent collapse, for example, of many bird species in France was traced to the use insecticides on industrial crops such as wheat, barley, corn and wine grapes.

“There are hardly any insects left – that’s the number one prob- lem,” said Vincent Bretagnolle, an ecologist at Centre for Biological Studies.

Experts estimate that flying insects across Europe have declined 80% on average, causing bird populations to drop by more than 400 million in three decades. Only a few species of insects – mainly in the tropics – are thought to have suffered due to climate change, while some in northern climes have expanded their range as temperatures warm.

In the long run, however, scientists fear that global warming could become another major driver of insect demise.

Up to now, rising concern about biodiversity loss has mostly focused on big mammals, birds and amphibians.

But insects comprise about twothirds of all terrestrial species, and have been the foundation of key ecosystems since emerging almost 400 million years ago.

“The essential role that insects play as food items of many vertebrates is often forgotten,” the researchers said.

Moles, hedgehogs, anteaters, lizards, amphibians, most bats, many birds and fish all feed on insects or depend on them for rearing their offspring.

Other insects filling the void left by declining species probably cannot compensate for the sharp drop in biomass, the study said.

Insects are also the world’s top pollinators – 75% of 115 top global food crops depend on animal pollination, including cocoa, coffee, almonds and cherries.

One-in-six species of bees have gone regionally extinct somewhere in the world.

Dung beetles in the Mediterranean basin have also been hit particularly hard, with more than 60% of species fading in numbers.

The pace of insect decline appears to be the same in tropical and temperate climates, though there is far more data from North America and Europe than the rest of the world.

Britain has seen a measurable decline across 60% of its large insect groups, or taxa, followed by North America (51%) and Europe as a whole (44%).

Ironically, the insect species that are bucking the global crash are among the small number that can harm humans, such as mosquitoes, which are spreading to other countries and spreading diseases.

These insects have adapted to human environments and are spread by human activity.

According to scientists and environmentalists, restoring wilderness areas and a drastic reduction in the use of pesticides and chemical fertiliser are likely the best way to slow the insect loss.

Buying organic food is among the actions people can take to curb the global decline in insects, as well as urging political action to slash pesticide use on conventional farms, they added.

“If you buy organic food, you make sure the land is used less intensively,” said Prof Axel Hochkirch, who leads on insects for the International Union for the Conservation of Nature.

“There are a lot of studies that show organic farming is better for insects than intensive farming. It is quite logical,” he told British daily The Guardian.

People with gardens could also make them more insect friendly by not mowing their lawn too frequently. Other measures proposed include planting plants which are native to the area and stopping the use of fertilisers and pesticides in the garden.

The Guardian also reported that the most critical large-scale action to help insects was reform of the enormous public subsidies given to intensive farming.

“This is the strongest threat to most species. It can only be dealt with on the political level. You need to change the system of how farmers are paid. It is not the farmer who is to blame, it is the system,” Hochkirch was quoted as saying.