Have you ever wondered how many ants there are in the world or whether they weigh more or less than all whales? Fortunately, with the release of a more rigorous analysis, you can now leave behind rough estimates and rounded calculations. But this work is not just an elaborate way of decoding internet arguments; It can help us understand the role that nearly ubiquitous insects play in ecosystems.
“Insects have long been viewed as ‘the little things that run the world,'” write one team of researchers, quoting biologist Edward O. Wilson. Despite this, information about their distribution and abundance is low, as scientists focus on larger and more charismatic things.
The authors combined studies of ant abundance in multiple environments to make predictions about land-dwelling and tree-dwelling ants found in nearly every major land-based ecosystem. The 20 quadrillion (20 x 1015) figure is double EO Wilson’s rough calculation, published in 1994, the first scientific effort to estimate ant numbers by making estimates from southeast England. But even the article’s estimate excludes colony members who do not leave their nests to forage, as well as areas where data is sparse, such as boreal forests.
Some findings may surprise non-entomologists. First, tree-dwelling ants outnumber their ground-dwelling cousins by about six to one. Those of us who think of ants as creatures living in underground burrows may not have spent enough time in the rainforest.
Taking into account the diversity of ant weights, the authors conclude that the dry carbon in these quadrillions of tiny bodies is about 12 megatons. If you sided with Formicidae (ants) and not cetaceans (cetaceans) on the question of who weighs more, you may be pleased to learn that you were right. The combined weight of all wild mammals and birds on the planet, including whales, reaches about 10 MT.
However, when compared to the total carbon in all life on Earth, ants are surprisingly small. In a previous study, it was calculated that all living things have 550 gigatons of carbon, that is, almost 50,000 times more. Most of this is plant life. The trees in which ants live weigh much more than ants, and fungi and bacteria also contribute large amounts to the total carbon.
The 15,700 ant species mentioned are inconspicuous even among animals. Altogether, we as humans currently have about five times more carbon in our bodies than ants do. Chickens, cows and sheep bred to feed and clothe us again account for much more than carbon.
The authors hope the study will be useful for examining how biodiversity changes across ecosystems and over time. As they point out, “The ants are estimated to dig up to 13 tonnes of soil per hectare per year, increasing local nutrient availability by an order of magnitude.” The authors note that among arthropods, ants account for only 1.2 percent of terrestrial species, but at least 6 percent of biomass…
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