Insects could become extinct within a century if their rapid rate of decline continues, according to the first global scientific review.
A damning study claims insects are on a doomed path towards oblivion, triggering a ‘catastrophic collapse’ in the planet’s ecosystems.
Scientists at the University of Sydney revealed Earth has entered its sixth mass extinction – the first since a giant asteroid slammed into modern-day Mexico and triggered the demise of the dinosaurs 66 million years ago.
The total mass of insects was found to be falling by 2.5 per cent a year and may become extinct in the next one hundred years, according to the research.
The speed at which insects are dying out is eight times faster than that of mammals, birds and reptiles, with analysis finding that more than 40 per cent of species are declining and a third endangered.
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A University of Sydney study says insects could become completely extinct within 100 years as a ‘sixth mass extinction’ beckons, scientists claim. They say industrial agriculture, climate change and urbanisation are to blame (stock)
Numbers of insects were found to be dwindling at an unprecedented rate and this prompted the researchers to issue a stark warning to the public as part of their scientific conclusions.
Writing in the ground-breaking paper, the researchers used an unusually forceful manner to drive the message home.
Its condemning tone is against the norm for scientific papers but was deemed necessary by both the authors of the study and the editors of the journal in order to bring the global crisis into view as 41 per cent of insect species have experienced decline in the last decade.
Figures show that 53 per cent of butterfly species have dropped over the past decade, while 46 per cent of bees species are in decline.
The worst hit group of all is the caddisfly with 68 per cent of species declining, but dragonflies and beetles have also seen a significant drop of 37 per cent and 49 per cent, respectively.
Intensive agriculture was found to be ‘the root cause of the problem’, but a host of issues were identified by the researchers as contributing to the insect genocide, such as climate change, urbanisation, habitat loss, disease and invasive species.
Insects are ‘essential’ to all ecosystems because of their role in pollinating plants and flowers, and as a food item for other creatures, the researchers say.
Any major decline in the amount of insect species will ultimately have a huge impact on humans too.
There have been recent reports of heavily declining insect numbers in Puerto Rico and Germany but the review claims the problem is a worldwide crisis.
Writing in the study, the researchers laid out their damning conclusions.
It read: ‘The [insect] trends confirm that the sixth major extinction event is profoundly impacting [on] life forms on our planet.
‘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.’
Francisco Sánchez-Bayo was one of the lead authors of the study and defending the use of the strongly-worded claims, insisting they are not alarmist.
Instead, he hopes the review’s dire outlook on insect numbers will ‘really wake people up’.
Francisco Sánchez-Bayo, at the University of Sydney, Australia, who wrote the review with Kris Wyckhuys at the China Academy of Agricultural Sciences in Beijing, said: ‘If insect species losses cannot be halted, this will have catastrophic consequences for both the planet’s ecosystems and for the survival of mankind.’
Forty-one per cent of insect species have experienced decline in the last decade (pictured). Since 1990, butterfly numbers dropped by 27 per cent in farmland and by 58 per cent in woodland and neonicotinoids has seen numbers of bees plummet
Butterflies and moths are among the worst hit. For example, the number of widespread butterfly species fell by 58 per cent on farmed land in England between 2000 and 2009. Any major decline in insect species will ultimately have a huge impact on the wider ecosystem and humans (stock)
He described the 2.5 per cent rate of annual loss over the last 25-30 years as ‘shocking’.
He said: ‘It is very rapid. In 10 years you will have a quarter less, in 50 years only half left and in 100 years you will have none.’
Insects are an essential part of the world’s ecosystem and are more plentiful and varied than any other group of animals.
There are more than 17 times the amount of insects than humans by weight alone.
Industrial farming and the associated use of chemical pesticides has been identified as the primary cause of decline but urbanisation and climate change have also been slated as key barriers to the revival of insects.
‘If insect species losses cannot be halted, this will have catastrophic consequences for both the planet’s ecosystems and for the survival of mankind,’ Dr Sánchez-Bayo told
He added that the 2.5 per cent loss of insects annually is ‘very rapid’ and ‘shocking’.
Puerto Rico has served as a long-running example of the devastating impact insect loss can have on the wider ecosystem.
WHAT IS EARTH’S SIXTH MASS EXTINCTION?
The world has experienced five mass extinctions over the course of its history, and experts claim we are seeing another one happen right now.
A 2017 research paper claimed a ‘biological annihilation’ of wildlife in recent decades has triggered the sixth mass extinction and says the planet is heading towards a ‘global crisis’.
Scientists warn humanity’s voracious consumption and wanton destruction is to blame for the event, which is the first major extinction since the dinosaurs.
Two species of vertebrate, animals with a backbone, have gone extinct every year, on average, for the past century.
Currently around 41 per cent of amphibian species and more than a quarter of mammals are threatened with extinction.
There are an estimated 8.7 million plant and animal species on our planet and about 86 per cent of land species and 91 per cent of sea species remain undiscovered.
Of the ones we do know, 1,204 mammal, 1,469 bird, 1,215 reptile, 2,100 amphibian, and 2,386 fish species are considered threatened.
Also threatened are 1,414 insect, 2,187 mollusc, 732 crustacean, 237 coral, 12,505 plant, 33 mushroom, and six brown algae species.
More than 25,000 species of 91,523 assessed for the 2017 ‘Red List’ update were classified as ‘threatened’.
The number of invertebrates at risk has also peaked.
Scientists predict insects may go extinct within 100 years as a result of crippling population decline.
The dawn of the mass extinction coincides with the onset of the Anthropocene – the geological age defined by human activity being the dominant influence on climate and the environment.
The widespread use of pesticides and, more specifically, neonicotinoids, has caused the numbers of bees (pictured) around the EU and US to drop dramatically. EU courts stepped in last year to prevent these from being used but it comes after the number of honeybee colonies in the US has dropped by 2.5 million since the end of the Second World War (stock)
It has seen the number of insects fall by 98 per cent in the last 35 years and the various fish, reptiles, amphibians and mammals that rely on them as a food source have since been in decline.
In order to get an accurate look at the state of the declining animal numbers around the world, the researchers collated 73 of the leading studies done in recent years.
Most were conducted in western Europe and the US, with some focusing on Australia, China, Brazil and South Africa.
There remains a vast gap in the collective knowledge of many other regions as more research is needed.
This included a fresh look at a study released in June 2018 which discovered that since 1990, butterfly numbers dropped by 27 per cent in farmland and by 58 per cent in woodland.
WHEN WERE EARTH’S FIVE GREAT EXTINCTION EVENTS?
Five times, a vast majority of the world’s life has been snuffed out in what have been called mass extinctions.
End-Ordovician mass extinction
The first of the traditional big five extinction events, around 540 million years ago, was probably the second most severe. Virtually all life was in the sea at the time and around 85% of these species vanished.
Late Devonian mass extinction
About 375-359 million years ago, major environmental changes caused a drawn-out extinction event that wiped out major fish groups and stopped new coral reefs forming for 100 million years.
Five times, a vast majority of the world’s life has been snuffed out in what have been called mass extinctions. The most famous may be the End-Cretaceous, which wiped out the dinosaurs. Artist’s impression
End-Permian mass extinction (the Great Dying)
The largest extinction event and the one that affected the Earth’s ecology most profoundly took place 252 million years ago. As much as 97% of species that leave a fossil record disappeared forever.
End-Triassic mass extinction
Dinosaurs first appeared in the Early Triassic, but large amphibians and mammal-like reptiles were the dominant land animals. The rapid mass extinction that occurred 201 million years ago changed that.
End-Cretaceous mass extinction
An asteroid slammed down on Earth 66 million years ago, and is often blamed for ending the reign of the dinosaurs.
Leafhoppers (pictured) constitute a large proportion of flying insects in Europe but numbers of the animal have plunged by 66 per cent by 1950 (stock)
This UK-focused study was part of a long-running research project and provided a wealth of data and information for analysis.
The report from the UK’s department for environment, food and rural affairs (DEFRA) called this an ‘ecological Armageddon’.
Nigel Bourn, director of science at Butterfly Conservation, told
‘That the worst five years ever for butterflies have all been in the last decade should ring major alarm bells,’ he explained.
Butterflies and moths are among the worst hit but another high-profile casualty of the insect Armageddon are bees.
The widespread use of pesticides and, more specifically, neonicotinoids, has caused the numbers of bees around the EU and US to drop dramatically.
WHAT ARE NEONICOTINOIDS?
Neonicotinoids are neuro-active chemicals similar to nicotine that have proved to be highly effective at protecting crops from pests, especially aphids and root-eating grubs.
They can either be sprayed on leaves or coated on seeds, in which case they infiltrate every part of the growing plant.
Years of research have shown that under controlled conditions the chemicals are toxic to honey bees and bumblebees, causing brain damage that can affect learning and memory and impair their ability to forage for nectar and pollen.
The chemicals are a key battleground in the environmental movement – with campaigners demanding a ‘complete and permanent’ ban on the pesticides as they are suspected to be harmful to bees.
Only two to 20 per cent of the neonicotinoids, which are still used on crops such as wheat, are taken up and the rest is left on the soil.
Samples taken in October revealed 75 per cent of samples from around the world contain the chemicals.
Researchers tested 198 honey samples and found three out of four were laced with at least one of the neonicotinoid chemicals.
For the study, an international team of European researchers tested almost 200 honey samples from around the world for residues left by five different neonicotinoids.
While in most cases the levels were well below the EU safety limits for human consumption, there were exceptions.
Honey from both Germany and Poland exceeded maximum residue levels (MRLs) for combined neonicotinoids while samples from Japan reached 45 per cent of the limits.
Samples from England had neonicotinoid levels that were no more than 1.36 per cent of the amount thought to be safe for human consumption.
EU courts stepped in last year to prevent these from being used but it comes after the number of honeybee colonies in the US has dropped by 2.5 million since the end of the Second World War.
Neonicotinoid eradication was heralded as a ‘major victory’ by campaigners but remains a small positive step in the face of overwhelming decline.
While areas of agricultural activity are likely seeing insects disappearing as a result of chemical usage, the tropical areas are being more heavily impacted by climate change, the researchers say.
Conditions in these areas have remained relatively constant and predictable for a long time, with the animal inhabitants poorly adapted to changing conditions.
In the wake of declining populations some adaptable species have found a way to overcome the widespread misery and thrive, but these pockets of success are unable to offset the wider decline.
The study is published in the journal