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How many ants live on earth? Scientists have an answer : ScienceAlert

Have you ever wondered exactly how many ants live on earth? Maybe not, but that’s certainly a question we’ve been asking ourselves.

Our study published today provides a rough answer. A conservative estimate is that our planet is home to about 20,000 trillion ants. This is 2 billion, or 20,000,000,000,000,000 in numeric form (20 and 15 zeros).

Furthermore, it is estimated that the world’s ants collectively constitute about 12 million tons of dry carbon. This is more than the world’s wild birds and wild mammals combined. It also corresponds to about one-fifth of the total human body weight.

Renowned biologist Edward O. Wilson once said that insects and other invertebrates are “the little things that make the world go round,” and he was right.

Ants in particular are an important part of nature. Among other roles, ants aerate soil, disperse seeds, decompose organic matter, create habitat for other animals, and form an important part of the food chain.

Estimating ant numbers and masses provides an important baseline for monitoring ant populations amid environmental changes of concern.

counting ants in the world

There are over 15,700 named species and subspecies of ants, many of which have yet to be scientifically named. Ants’ advanced social organization has allowed them to colonize nearly every ecosystem and region around the world.

The amazing ubiquity of ants has led many naturalists to ponder the exact number of ants on Earth.

But these were basically educated guesses. A systematic, evidence-based estimation was lacking.

Our study included an analysis of 489 studies on ant populations conducted by fellow ant scientists around the world. This included non-English literature in languages ​​such as Spanish, French, German, Russian, Mandarin and Portuguese.

Studies spanned all continents and major habitats, including forests, deserts, grasslands and cities. They used standardized methods of collecting and counting ants, such as pit traps and leaf litter samples. As you can imagine, this is often a tedious task.

All of this puts us at an estimated 20,000 trillion ants on Earth. While this number is conservative, it is two to twenty times higher than previous estimates.

Previous figures have taken a “top-down” approach, assuming that ants make up about 1% of the world’s estimated insect population.

In contrast, our ‘bottom-up’ estimation uses data from ants directly observed in the field and makes fewer assumptions, making it more reliable.

Our next step was to calculate the weight of all these ants.The mass of an organism is usually measured by its carbon composition.

It is estimated that 20,000 trillion average-sized ants correspond to about 12 million tons of carbon dry weight or “biomass.”

This is more than the biomass of wild birds and mammals combined, and about 20% of all human biomass.

Carbon makes up about half of the ant’s dry weight. The total mass of ants in the world would be even greater if the weights of other body elements were included.

We also found that ants were unevenly distributed on the Earth’s surface. They differ six-fold between habitats and generally peak in the tropics. This highlights the importance of tropical areas in maintaining healthy ant populations.

Also, ants are especially abundant in forests, and surprisingly, they also live in dry areas. However, they become less common in man-made habitats.

Our findings have several caveats. For example, the sampling locations of the dataset are unevenly distributed across geographic regions.

Also, most of the samples were collected from strata, leaving little information on tree and subterranean ant populations.

Many ant species are important seed dispersers.Here, two workers Melano Plus Ants bring the seeds back to their nests. (Francois Brassard)

we all need ants

Ants also provide essential “ecosystem services” to humans. For example, a recent study found that ants may be more effective than pesticides in helping farmers produce food.

Ants have also developed close interactions with other organisms – and some species cannot survive without them.

For example, some birds rely on ants to wash down their prey. Thousands of plant species feed and build nests for ants in exchange for protection and seed dispersal. Many ants are also predators, helping to keep other insect populations in check.

Surprisingly, threats such as habitat destruction and fragmentation, chemical use, invasive species, and climate change are reducing the world’s insect populations.

However, data on insect biodiversity are surprisingly scarce. We hope that our study provides a baseline for further research that will help fill this gap.

Monitoring ant populations is in the interest of mankind. Counting ants is not difficult. It could help citizen scientists around the world investigate how these important animals thrive in times of great environmental change.conversation

Mark Wong, Forest Fellow, University of Western Australia. Benoit Guénard, Associate Professor, University of Hong Kong. François Brassard, PhD Candidate, Charles He Darwin University. Patrick Schulteis, Adjunct Research Fellow at the Julius-Maximilians-Universität Würzburg. Her Runxi Wang, her PhD candidate at the University of Hong Kong, and her Sabine Nooten, interim principal investigator at Julius Her Maximilian University in Würzburg, said:

This article is republished from The Conversation under a Creative Commons license. Please read the original article.