Earth has 20 quadrillion ants, says new population study

It’s the world of ants, and we’re just leaving.

A new estimate of the total number of burrowing and buzzing ants on Earth totals about 20 quadrillion individuals.

This staggering amount – 20,000,000,000,000,000, or 20,000 trillion – reveals the astonishing ubiquity of ants, even as scientists are concerned that potential mass death from insects could overwhelm ecosystems.

In a paper released Monday by the Proceedings of the National Academy of Sciences, a group of scientists from the University of Hong Kong analyzed 489 studies and concluded that the total mass of ants on Earth weighs about 12 megatons of dry carbon.

Put another way: If all the ants were removed from the ground and placed on a scale, they would put all the wild birds and mammals together. There are about 2.5 million ants for each person.

“This is unimaginable,” study lead author Patrick Schultheis, now a researcher at the University of Würzburg in Germany, said in a Zoom interview. “For example, we can’t just imagine 20 quadrillion ants in a heap. It just doesn’t work.”

Counting all those insects — or at least one of them to come up with a sound estimate — involves combining data from “thousands of authors in many different countries” over a period of a century, Schulthis said.

To match insects as abundant as ants, there are two ways to do this: get down on the ground to sample leaf litter – or set up small pit traps (often just a plastic cup) and watch for ants to slip. wait. Researchers have found their shoes are dirty from surveys in almost every corner of the world, although data is lacking in some places in Africa and Asia.

“It’s a really global effort that goes into these numbers,” Schultheis said.

Ants, like humans, have marched on almost every continent and in all kinds of habitats. According to the research team, land ants are most abundant in tropical and subtropical regions, but they can be found almost everywhere except in the coldest parts of the planet.

Or the famous author and myrmecologist (which means ant scientist) EO Wilson put it once: “No matter where I go – except possibly Antarctica or the High Arctic, and I don’t go there because there are no ants – no matter how different human culture, no matter how different the natural environment, there There are ants.”

The world could, in fact, be better than all these ants. By creating tunnels, they aerate the soil and drag the seeds under the ground to germinate. They serve as a source of food for untold arthropods, birds and mammals. While carpenter ants are pesky to homeowners, without the decomposing power of wood-destroying insects, forests would be piled with dead wood.

Entomologists are seeing worrying declines in insect populations beyond ants in Germany, Puerto Rico and elsewhere. Habitat destruction, pesticides and climate change contribute to this likely-but-still-debating ,Bugpocalypse. “More than 40 percent of insect species may become extinct, According to a 2019 studyThe biggest threats are faced with butterflies and beetles.

Scientists aren’t sure whether ant numbers are falling as well. “To be honest,” Schultheis said, “we have no idea.”

That’s the next research question the team wants to answer. “We have not yet attempted to show this temporal change in ant abundance,” said Sabine Knuten, an insect ecologist and co-lead author of the study, by Zoom. “That would be something that would come next.”

For decades, scientists have observed ant farms in laboratories to test theories on animal behavior. Ant scientist Wilson, Joe dead Last year, ants used their insights to help explain the genetic basis for cooperation between animals and to preserve life’s vast biodiversity.

In the 1990s, he made a rough estimate on Earth’s ant population with fellow biologist Bert Holdobler. His estimate was about 10 quadrillion — within the same order of magnitude as the more recent, more rigorous estimate published Monday.

“In the case of EO Wilson, he was simply a very smart guy,” Schultheis said. “He knew a lot about ants and basically had a gut feeling.”

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