Do you know how many ants live on Earth? It may not be true, but we have certainly asked ourselves the question.
We provide an approximate answer in our research published today. Approximately 20 quadrillion ants live on our planet, according to conservative estimates. The numerical equivalent is 20,000,000,000,000,000 (20 with 15 zeros).
Furthermore, it is estimated that the world’s ants contribute about 12 million tons of carbon to the atmosphere. There are more wild birds and wild mammals in the world combined than there are wild birds and wild mammals combined. A human being weighs about one-fifth of that amount.
Edward O. Wilson, an eminent biologist, once remarked that insects and other invertebrates “run the world”. The ant is a crucial part of nature, in particular. As well as aerating soil, dispersing seeds, destroying organic materials, and creating habitats for other animals, ants play a crucial role in the food chain.
Monitoring ant populations amid worrying environmental changes requires estimating ant numbers and mass.
Counting the world’s ants
Thousands of species and subspecies of ants have been named by science, and many more are yet to be discovered. Due to their high degree of social organization, ants have colonized nearly all ecosystems and regions on earth.
Ants are ubiquitous on Earth, leading many naturalists to speculate about their exact number. However, these were essentially educated guesses. The lack of systematic, evidence-based estimates has been a problem.
In our study, we analyzed 489 studies of ant populations conducted around the world by fellow ant scientists. In addition to English, this included literature in Spanish, French, German, Russian, Mandarin, and Portuguese.
In addition to forests, deserts, grasslands, and cities, the research covered all continents. Their methods for collecting and counting ants included pitfall traps and leaf litter samples. You can imagine how tedious this can be.
Based on all this, we estimate that there are approximately 20 quadrillion ants on Earth. It is between two and twenty times higher than previous estimates, despite being conservative.
In the previous figures, ants were assumed to make up about 1% of the world’s estimated insect population based on a “top-down” approach. Our “bottom-up” estimate is more reliable because it uses direct observations of ants in the field and makes fewer assumptions.
As a next step, we calculated the weight of all these ants. Typically, organisms are measured based on their carbon composition. According to our calculations, there are approximately 12 million tonnes of carbon in 20 quadrillion average-sized ants.
About 20% of the total human biomass is composed of this material. This is more than the combined biomass of wild birds and mammals.
The dry weight of an ant is approximately half carbon. The total mass of the world’s ants would be even higher if other bodily elements were included.
The distribution of ants on Earth’s surface is also uneven. In the tropics, they typically peak sixfold and vary sixfold between habitats. As a result, tropical regions are critical for maintaining ant populations in good health.
Ants were also particularly abundant in forests, and, surprisingly, in arid areas as well. Human-made habitats, however, make them less common.
There are a few caveats to our findings. There is an uneven distribution of sampling locations across geographic regions in our dataset, for example. Our data on ant numbers in trees and underground are limited because the majority of samples were collected from the ground layer. The results of our study are therefore somewhat incomplete.
Why Ants are Important?
Humans also benefit from ant “ecosystem services.” According to a recent study, ants can help farmers produce food more efficiently than pesticides.
It is also important to note that ants have developed tight relationships with other organisms – and some species cannot survive without them.
Some birds use ants to flush out their prey, for example. As a result, thousands of plant species feed or house ants in exchange for protection or seed dispersal. Additionally, many ants are predators, helping to control populations of other insects.
There is an alarming decline in insect numbers around the world due to threats such as habitat destruction, fragmentation, chemical use, invasive species, and climate change.
However, insect biodiversity data are alarmingly scarce. In order to fill this gap, we hope our study serves as a baseline for further research.
Monitoring ant populations is in humanity’s best interests. It is not difficult to count ants, and citizen scientists from around the world could help investigate how these important animals are faring amidst a changing environment.