Over 40 percent of insect species face extinction: study

From butterflies to bees, nearly half of all insect species are threatened with extinction "over the next few decades." Scientists have warned of the devastating impact it could have on the future of humankind.

New research published Sunday suggests more than 40 percent of insect species "are threatened with extinction."

For years now, scientists have warned of the devastating impact the loss of insects, especially pollinators, will have on the future of humankind.

Species affected:

  • Butterflies and moths
  • Bees and wasps
  • Beetles
  • Dragonflies, among others

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Monarch butterflies losing ground

One-of-a-kind

The monarch butterfly is a migrating marvel: It's the only insect that every year travels for two months and up to 5,000 kilometers (3,100 miles), from Canada and the United States to Mexico, where it spends the winter. There, the monarch butterfly roosts in the pine and fir forests in the Sierra Madre mountains west of Mexico City, which protect the insects, and help keep them from freezing.

Monarch butterflies losing ground

Mysterious insect

Not just the distance is amazing — also the butterflies' sense of direction fascinates scientists and experts. The monarch butterfly divides its migration over three generations, meaning no single butterfly lives long enough to make the roundtrip back to the US and Canada. And still, year in and year out, they seem to know exactly where they are heading.

Monarch butterflies losing ground

A perfect cycle

The butterfly synchronizes its lifecycle with milkweeds by laying its eggs on the plant in the US. In fall, when the milkweeds start to die, a young generation of monarch butterflies leave for Mexico. As soon as the first milkweeds appear in spring, the monarch butterfly returns to begin the cycle anew. There's evidence that they possess a genetically coded instinct for which direction to fly.

Monarch butterflies losing ground

Agricultural pest

Milkweed is considered a pest in farming — industrial agricultural practices including monculture cropping and intensive pesticide use has decreased the plant that monarchs rely upon. It's one of the factors linked to monarch butterflies' decline.

Monarch butterflies losing ground

Magnetic Compass

The baby butterflies that set off on the migration have never been to Mexico and therefore can't know the route. But still, the monarchs always find their way back to the Mexican reserve, where they wait out the winter. Studies in 2014 and 2016 suggest the sun offers orientation. In addition, the insects possess an inner magnetic compass corresponding to the Earth's magnetic field.

Monarch butterflies losing ground

Hard to count

Despite monarch butterflies being perfectly equipped to take on the vast distance each year, their numbers are decreasing nonetheless. It is hard to count individual butterflies, though, so experts came up with a specific method of assessing how many butterflies have migrated back to Mexico: They look at the area of forest the monarch butterfly covers.

Monarch butterflies losing ground

Declining numbers

And this area has declined dramatically. Since the winter of 1996-1997 it has shrunk, from about 44 acres (18 hectares) to 6 acres (2.5 hectares) in the winter of 2017. The reasons for this are diverse, among them more intense storms and busy hurricane seasons. Such extreme weather disturbs the insects' migration route and uproots trees, which the butterflies rely on in order to survive.

Monarch butterflies losing ground

Competing with avocados

Other reasons for the butterflies' decline include illegal logging and land use changes. Monarch butterflies migrate to pine and fir forests that thrive at about the same altitude as prime avocado-growing land. In February 2018, Mexican police shut down an illegal avocado plantation that had been set up in the Monarch butterfly's overwintering grounds.

Monarch butterflies losing ground

No trees, no butterflies

On the positive side, Mexican officials claim to have nearly eliminated illegal logging in butterfly refuge zones. Fighting such deforestation is key, because the spectacular migration of thousands of Monarch butterflies can only continue if there are enough trees for the monarch butterfly to find shelter in.

'Threatened worldwide'

Researchers said:

  • "Biodiversity of insects is threatened worldwide."
  • "Our work reveals dramatic rates of decline that may lead to the extinction of 40 percent of the world's inspect species over the next few decades."
  • "Affected insect groups not only include specialists that occupy particular ecological niches, but also many common and generalist species."
Nature and Environment | 05.12.2018

Read more: Climate change reduces male fertility, could help drive extinction

What is the problem?

The researchers, whose work was published in the leading international journal in the discipline of conservation science, Biological Conservation, pointed to several factors, including habitat loss, pollution, pesticides and biological factors, such as pathogens. They also cited climate change, saying "it is particularly important in tropical regions."

Although the researchers did not go into detail about the knock-on effects, scientists have warned of the potential for disaster, especially with reduced pollinator populations, and urged concrete action to protect critical species.

"Failure to do so will jeopardize food security by posing imminent threats to the global economy, nutrition and diet diversity, and the biodiversity of ecosystems," said the Chicago Council on Global Affairs in a report. "But our success in doing so will ensure our ability to feed a growing population for generations to come."

Read more: 'Our consumption choices are driving biodiversity loss'

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Can we change it?

According to the researchers led by Francisco Sanchez-Bayo of the University of Sydney and Kris A.G. Wyckhuy of the University of Queensland, there are several steps that can be taken to mediate losses and reverse the trend.

"A 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, allow the recovery of declining insect populations and safeguard the vital ecosystem services they provide," the researchers said.

Read more: Climate change could cause 'severe' global beer shortage

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Seven plants with medicinal powers

Bitter bark

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Seven plants with medicinal powers

Fragrant remedies

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Wake me up

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Miracle worker

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Seven plants with medicinal powers

Combating yawns

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Jack of all trades

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Dandelion improvements

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