Finally someone has calculated the number and weight of all the ants in the world

Don’t say you’ve never wondered how many ants there are in the world, or if they weigh more or less than all the whales. However, after the release of a more rigorous analysis, rough guesses and back-of-the-envelope calculations may now emerge. The work isn’t just an elaborate way to settle internet disputes — it could help us understand the role these nearly ubiquitous insects play in ecosystems everywhere.

Insects “have long been thought of as the ‘little things that rule the world,'” writes the research team, citing biologist Edward O. Wilson. Despite this, they find that knowledge of their prevalence and frequency is scant as scientists have focused on larger and more charismatic things.

To address this, the authors combined studies of ant abundance in many environments to provide estimates of the ground-dwelling and tree-dwelling ants present in nearly every major land-based ecosystem. Your number of 20 trillion (20 x 10fifteen) is a double very crude calculation by EO Wilson published in 1994 – the first scientific attempt to estimate ant numbers by extrapolation from south-east England. But even the paper’s estimate omits members of colonies that do not leave their nests to forage, as well as areas such as boreal forests where data are scarce.

Some of the results may surprise non-entomologists. For one thing, tree-dwelling ants outnumber their ground-dwelling relatives by about six to one. For those of us who think of ants as underground nests, it seems we just haven’t spent enough time in the rainforest.

Taking into account the different ant weights, the authors conclude that the dry carbon in these quadrillion small bodies is about 12 megatons. If you chose Formicidae vs. Whales in the weight contest, you can take a bow. All the wild mammals and birds on the planet add up to about 10 tons, of which whales are just a part.

On the other hand, ants are surprisingly puny relative to the total carbon of all life on Earth. A previous study calculated that 550 gigatonnes of carbon – nearly 50,000 times that amount – are incorporated into living things. Most of it is plant life; The trees that ants live in weigh a lot more than themselves, and fungi and bacteria add up to a lot.

Even among the animals, the 15,700 named ant species do not stand out. Humans now have about five times as much carbon in our collective body as ants. The chickens, cows and sheep that feed and clothe us have significantly more again. Despite human activity, there are also many more fish in the sea (by weight).

The authors hope the work will be useful in studying how biodiversity changes between ecosystems and over time. As you note; “Ants are estimated to dig up to 13 tons of soil per hectare annually, increasing local nutrient availability by an order of magnitude.” Among arthropods, the authors note that ants make up only 1.2 percent of terrestrial species, but at least 6 percent make up the biomass.

Of course, all of these calculations will have to be adjusted if someone decides to release the double-sized ants, developed seven years ago, into the wild.

The study was published in Proceedings of the National Academy of Sciences.

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