More than 40% of the species of insects could disappear in the next decades, according to the report "Decline of the entomofauna in the world: an overview of its factors", published in the journal Biological Conservation.
The report indicates that the biomass of insects is decreasing by 2.5% per year, indicating widespread extinctions over a century.
In addition to the 40% of people threatened with extinction, one third of the species are in danger – a number that could cause the collapse of the planet's ecosystems and have a devastating impact on life on Earth.
The report, co-written by scientists from the Universities of Sydney and Queensland and the Academy of Agricultural Sciences of China, examined dozens of existing reports on insect dieback published over the last three decades, as well as that the reasons for the fall in the number of insects. alarming overall picture.
Its lead author, Francisco Sanchez-Bayo, of the School of Life Sciences and the Environment at the University of Sydney, called the study a truly comprehensive first review of the issue.
In the past, the focus had been on the decline of vertebrate animal biodiversity, but this study underscored the importance of insect life for interconnected ecosystems and the food web. Insects make up about 70% of all animal species.
The impact of the extinction of the insects would be "at least catastrophic", according to the report, because the insects constitute "the structural and functional base of many global ecosystems since their ascent … there are nearly 400 millions of # 39; years. "
The main causes of this decline are "habitat loss and conversion to intensive agriculture and urbanization", pollution, including pesticides and fertilizers, as well as biological factors, such as "pathogens and pathogens". introduced species "and climate change.
While a large number of specialized insects, which occupy a specific ecological niche, and as insects in general declined, a small group of adaptable insects saw their numbers increase – but not enough to stop decline, according to the report.
Small creatures running the world
Don Sands, entomologist and retired scientist of the Commonwealth Scientific and Industrial Research Organization, said that he was "quite" in agreement that the effects "of the base "of the loss of insects are serious.
"If we do not have insects as moderators of other pest populations, we have insect populations that ignite and ruin crops." and make them difficult to cultivate, "he said.
He added that the ecosystem at this level must be "in balance." This is the bottom layer and if we do not tackle it, all our lives could suffer enormous consequences.
"(Insects are) the little creatures that rule the world," he said.
Insect decline reports are not new: researchers have been warning about the phenomenon and its impact for years.
"These are not agricultural areas, they are places to preserve biodiversity, but we still see insects get out of our hands," said co-author Caspar Hallman.
Birds eating birds
Scientists say that insect-dependent species – and predators high up in the food chain that eat them – are likely to suffer from this decline. Pollination of wild crops and plants would also be affected, as would the nutrient cycle in the soil.
According to the study, about 80% of wild plants use insects for pollination, while 60% of the birds feed on insects. Sands said the immediate decline of insects posed an immediate danger, namely the loss of insectivorous birds and the risk that larger birds would feed each other on insects.
In his native Australia, "the birds that lack insects are turning around," he said, adding that it was probably a global phenomenon.
Radical action needed
The report's authors called for radical and immediate action.
"Insects are the most abundant and diverse group of animals in the world and provide essential services within ecosystems, such events can not be ignored and should prompt decisive action to prevent a catastrophic collapse. natural ecosystems, "they wrote.
They suggested reviewing existing farming methods, "in particular a significant reduction in the use of pesticides and its substitution by more sustainable and ecological practices".
"The conclusion is clear: unless we change our methods of food production, the insects as a whole will fall on the path to extinction in a few decades," they concluded.