Tuesday , January 26 2021

Insect population and species reject a "wake-up call", researchers say – science news



If you are old enough, remember to dry the clear remnants of turbines, grasshoppers and other insects from your windscreen as you drive through the regional Australia.

key points insects

Key points:

  • Researchers examined 73 longitudinal studies of insect populations from around the world
  • On average, 41 per cent Of the known insect species in the population decline studies
  • Losses were reported across all insect groups, but some species grew in number

According to Francisco Sanchez-Bayo, a great Australian tradition has gone.

"When I started studying, we had to stop every time we filled up with gas to clean the windshield because it was full of mills and crickets and insects of all kinds. And now there is none," he said.

It is anecdotal evidence, but it is supported by the first global review of insecticide studies worldwide and the reasons for what was done by dr. Sanchez-Bayo, an honorary association at the University of Sydney and recently published in Biological Conservation.

"Among them, one third of all species go into extinction. They are in danger right now. The rate of rash in insects is about eight times higher than the rate of extermination of vertebrates."

Dr. Sanchez-Bayo and his colleague Kris Whyckhuys analyzed all the long-term studies of insect populations they could find. The majority of the 73 studies were from Western Europe and the United States, with only a handful of studies from other parts of the world and only one from Australia.

A study in Germany experienced a 75 percent decrease in insect biomass over 27 years. Another study in Puerto Rico reported losses of between 78 and 98 percent over 36 years.

The rate of decline is so dramatic – up to 2.5 percent per year – that Dr. Sanchez-Bayo claims that insects cannot currently occur in these regions within 10 years.

Losses were reported across all insect groups, although some species grew in number, he said.

"Those who are to die out are specialized species that require very specific conditions to live on," Sanchez-Bayo said.

Insect decline claims & # 39; not backed up & # 39;

That is why manu Saunders, a researcher in ecosystem services, believes that the claims of catastrophic decline from dr. Sanchez-Bayo is overrated.

"It's an important wake-up call that insect populations change in some places."

"But to claim worldwide decline of all insects is not backed up by what data is actually available."

Many insect species on Earth have not been described yet, so we do not know about them – where they live, how they live, what their life cycle is, what affects them.

"Many insects could be affected worse, or they could not be so bad, but the point is that we don't actually know," said Dr. Saunders.

In Australia, most of our original insect species have not yet been identified. The only study suitable for inclusion in Dr. Sanchez-Bayo's analysis was on commercial honey bees in Queensland.

So what causes fall?

There were many different reasons for the decrease in the investigated studies.

Dr. However, Sanchez-Bayo found that there were four important factors: habitat loss; pollution, in particular pesticides and fertilizers; biological factors, including pathogens and introduced species; and climate change.

The dramatic loss of insect biomass in Puerto Rico was largely due to climate change, with a strong correlation with the frequency of severe cyclones and subsequent forest destruction.

In Germany, the reduction of insects was attributed to the introduction and increased use of systemic pesticides used as prophylactic against pest infestations.

"If you live in the tropics, it is most likely that deforestation and climate change are [that are responsible for declining insect populations]but in Europe – where deforestation is no longer a problem – it is the use of chemical fertilizers and pesticides, and the reduction of other elements that used to be present in the agricultural landscape, such as hedges, trees, flowers, weeds. "

However, Dr Saunders points out that we cannot necessarily extrapolate the information to Australia or other areas not covered by the audit.

"It is OK to wonder that these drivers are likely to have the same influence on areas where we have no data, but we cannot say it unequivocally."

When the insects go, the animals go

Dr. Sanchez-Bayo is aware that his claims are dramatic, but considers it important to draw attention to this issue.

"We are trying to ring the alarm bells very loudly so everyone listens," he said.

In addition to all the important functions that insects play in our ecosystems – such as pollination or recycling of nutrients – they are also an essential element of the food chain that supports life on our planet. When the insects go, the frogs, the birds and the mammals do not have food.

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