Insects could disappear 'all at the same time': scientist

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Josh Dehaas CTVNews.ca Writer

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A new research paper has come to the startling conclusion that without changes to the way we produce our food, “insects as a whole will go down the path of extinction in a few decades.”

The review published in the journal Biological Conservation looked at 73 studies that measured the prevalence of insects, mostly in North America and Europe. They calculated that populations are declining at an average rate of 2.5 per cent annually.

Examples of the studies included are a 27-year-long study in Germany that found a 76 per cent decline in flying insect biomass and a 36-year-long study in Puerto Rican rainforests that found losses of 98 per cent of ground-foraging and 78 per cent of canopy-dwelling arthropods.

Study co-author Francisco Sanchez-Bayo, an ecologist at the University of Sydney in Australia, told CTV News Channel on Monday that we could lose insects “all at the same time.”

“They’re all going down in parallel,” he said.

Researchers identified four major causes for the declines, Sanchez-Bayo explained.

“The first one obviously is the habitat loss,” he said. “That’s due to agricultural practices, urbanization and deforestation.”

The second factor, he said, is “pollution by pesticides and industrial chemicals of different kinds.”

“A small contribution of biological factors like invasive species and pathogens” is the third factor, according to Sanchez-Bayo.

The fourth major cause -- and least significant of the group, the researchers say -- is climate change. “Not only the warming we’ve experienced in the last century but also the cyclones (are) devastating.”

The researchers say that “rethinking of current agricultural practices, in particular a serious reduction in pesticide usage and its substitution with more sustainable, ecologically-based practices, is urgently needed to slow or reverse current trends.”

“In addition, effective remediation technologies should be applied to clean polluted waters in both agricultural and urban environments,” they write.

Sanchez-Bayo said that losing insects altogether would have dramatic impacts on other species – including humans – because we would lose all of the “ecosystem services they provide.”

“For example, pollination in the case of the bees or butterflies (and) some of the beetles as well,” he said.

“We have to bear in mind (that) insects provide the main food source for innumerable species of vertebrates,” Sanchez-Bayo added, pointing to birds, bats, frogs, reptiles and freshwater fish as examples. “All these other species of vertebrates will go down with the insects at the same time.”

RELATED IMAGES A Monarch butterfly rests in the Amanalco de Becerra sanctuary, on the mountains near the extinct Nevado de Toluca volcano, in Mexico, Thursday, Feb. 14, 2019. In January, Mexican officials announced that the population of monarch butterflies wintering in central Mexico was up 144 percent over the previous year. (AP Photo/ Marco Ugarte)