Scientists are warning of 'ecological Armageddon' after discovering the number of flying insects has fallen by three-quarters over the past 27 years.

Researchers in Germany have documented a steep decline at dozens of nature reserves.

Their findings have sparked fears the foodchain will collapse because insects are important pollinators and serve as meals for birds and other small creatures.

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Scientists are warning of 'ecological Armageddon' after discovering the number of flying insects has fallen by three-quarters over the past 27 years. Pictured is a hoverfly, one of the insects whose numbers have declined dramatically

WHAT ARE THE CONSEQUENCES? Around 80 per cent of all of the world's plant life is of the flowering variety. This means to reproduce, they must have pollen physically transferred from a male anther to the female stigma. Insects are important pollinators and without them these plants would disappear. This would be devastating to the rest of the world, as animals and humans rely on these plants for food. Between 50 and 90 percent of the human diet comes directly from flowering plants. They also bury animal dung and prey on pests. Because they serve as major decomposers of organic material, without insects the world would be full of corpses. Advertisement

It is thought the decline may be caused by agricultural pesticides used to stop insects eating crops.

It comes after drivers across the UK have been reporting noticing fewer flies, gnats, wasps and moths than usual on their vehicles.

The trend has also been spotted elsewhere.

'For those of us who look, I think all of us are disturbed and all of us are seeing fewer insects,' Scott Black, executive director of the Portland-based Xerces Society, a nonprofit environmental group told the Washington Post.

'On warm summer nights you used to see them around streetlights.'

For the study published in Plos One, researchers used sticky traps to collect insects at 63 nature reserves, then measured the biomass, documenting changes over time.

Over the past 27 years, they found an average decline of 76 percent, with the effects appearing worst in summer (82 percent).

'The fact that flying insects are decreasing at such a high rate in such a large area is a very alarming discovery,' said lead researcher Hans de Kroon of Radboud University.

Shown here is the average weight of trapped insects per day against the years 1989 until 2016. After 27 years, the total average weight has been declined by more than 75 per cent

Professor Dave Goulson of Sussex University told The Guardian: 'Insects make up about two-thirds of all life on Earth [but] there has been some kind of horrific decline.

WHY ARE INSECTS DISAPPEARING? While the study did not pinpoint a reason for the drop, researchers said many nature reserves are encircled by farm fields, and that pesticides could be to blame. The use of chemical pesticides can, in addition to killing pests, also kill 'good bugs' that help keep pests in balance. Lead researcher Hans de Kroon of Radboud University said: 'The only thing we can do right now is to maintain the utmost caution. 'We need to do less of the things that we know have a negative impact, such as the use of pesticides and prevent the disappearance of farmland borders full of flowers. 'But we also have to work hard at extending our nature reserves and decreasing the ratio of reserves that border agricultural areas.' Advertisement

'We appear to be making vast tracts of land inhospitable to most forms of life, and are currently on course for ecological Armageddon.

'If we lose the insects then everything is going to collapse.'

Around 80 per cent of all of the world's plant life is of the flowering variety.

This means to reproduce, they must have pollen physically transferred from a male anther to the female stigma.

Insects are important pollinators and without them these plants would disappear.

This would be devastating to the rest of the world, as animals and humans rely on these plants for food.

Between 50 and 90 percent of the human diet comes directly from flowering plants.

They also bury animal dung and prey on pests. Because they serve as major decomposers of organic material, without insects the world would be full of corpses.

While the study did not pinpoint a reason for the drop, researchers said many nature reserves are encircled by farm fields, and that pesticides could be to blame.

'As entire ecosystems are dependent on insects for food and as pollinators, it places the decline of insect eating birds and mammals in a new context,' said de Kroon.

Researchers used sticky traps to collect insects at 63 nature reserves, then measured the biomass, documenting changes over time. Shown here is a one of the traps (the white 'tent') in one of the research nature reserves, bordered by farmland

'We need to do less of the things that we know have a negative impact, such as the use of pesticides,' he added.

'We also have to work hard at extending our nature reserves and decreasing the ratio of reserves that border agricultural areas.'

This is not the first study to point out that insect levels have fallen sharply in recent years.

In 2013, The Krefeld Entomological Society - a German amateur group of entomologists that monitored more than 100 nature reserves in western Europe since the Eighties - returned to one of its trapping sites from 1989 and found the number of insects had dropped by nearly 80 per cent, Science Mag reported.

Analysis of further samples confirmed the phenomenon.

According to Dave Goulson, an ecologist at the University of Sussex who is working with Krefeld Entomological Society, other species are at risk, too.

HOW BEES ARE AFFECTED BY PESTICIDES Queen bees emerge from hibernation in spring to fly off to continue the bees' life cycle in a new colony. An agricultural dose of thiamethoxam reduces their ability to do this, and boosts the risk of population collapse. When a queen is going to set up a colony, she will secrete wax and form it into containers for nectar and pollen. She will then begin to lay her eggs and sit on them like a bird - these spring queens represent the next generation of bumblebee colonies. But exactly how thiamethoxam blocks the queens' reproductive cycle is not yet known. Advertisement

Drivers have been reporting fewer flies, gnats, wasps and moths than usual on their vehicles

'If you're an insect-eating bird living in that area, four-fifths of your food is gone in the last quarter-century, which is staggering,' he told the magazine earlier this year.

'One almost hopes that it's not representative - that it's some strange artifact.'

The so-called 'windscreen phenomenon' has been blamed by experts on the increasing use of pesticides over the past 50 years.

And it's not just the kind of insect you find on your windscreen that is affected.

Since 2006, bee colonies have declined by about a third due to the chemicals, as well as the loss of flower-rich grassland.

This was backed up by Matt Shadlow, chief executive of the insect charity Buglife, who told the paper: 'Yes, indeed this is a well-recognised phenomenon.

'Just today we had a member of the public phone up and say, unprompted, that 'the front of my car is now devoid of insects, and there are virtually no moths in the headlights.'