Dramatic declines in insect numbers could see 40% of species die out in the "largest extinction event on Earth" for millions of years.

Scientists have warned of a catastrophic collapse of nature’s ecosystems if numbers continue to decline, as insects are key to many of the world’s natural systems and wildlife chains.

Insects provide a food source to other wildlife such as birds and mammals, and are also important for pollinating plants and recycling nutrients.

Researchers say the agricultural industry is largely to blame for declining populations, with destruction of habitat and the widespread use of pesticides having a major impact.

Other factors include disease and introduced species, as well as climate change, with rising temperatures affecting the range of places insects can live.

The Earth is currently facing its sixth mass extinction, according to another study published in the peer-reviewed journal Proceedings of the National Academy of Sciences.

The report found billions of animal species have been lost over the last few decades in a biological annihilation of wildlife.

Insect numbers are declining by 2.5% each year and a third of species are endangered, meaning many face extinction by the end of the century.

They currently make up more than half of the world’s species, but research shows they are disappearing much faster than birds and mammals.

The latest study, published in the journal Biological Conservation, found butterflies, bees and dung beetles were among the worst hit.

This not only affected specialist species which rely on particular host plants or habitats, but more hardy types as well.

Scientists say urgent action is needed to prevent the mass extinction.

The study’s authors, Francisco Sanchez-Bayo and Kris Wyckhuys, said: The conclusion is clear: unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades.

The repercussions this will have for the planet’s ecosystems are catastrophic to say the least, as insects are at the structural and functional base of many of the world’s ecosystems since their rise at the end of the Devonian period, almost 400 million years ago.

They called for a dramatic reduction in the use of pesticides, habitat restoration and changes to agriculture, such as planting flowers along the margins of fields.

The chief executive of the wildlife charity Buglife called the report gravely sobering and also urged change.

It is becoming increasingly obvious our planet’s ecology is breaking and there is a need for an intense and global effort to halt and reverse these dreadful trends – allowing the slow eradication of insect life to continue is not a rational option, said Matt Shardlow.

Falling insect populations have been the subject of concern for a number of years, with a report published last year finding species in German nature reserves had declined by more than 75% during the 27-year study.

(c) Sky News 2019: Insect species could fall by 40%, causing ‘catastrophic collapse’ of world’s ecosytems