What is the estimated global population of ants?

From the depths of tropical forests to arid deserts, ants are omnipresent, colonizing almost every corner of the globe. Their discreet but constant presence masks a dizzying reality: they are among the most numerous creatures on the planet. But how many ants are there in the world? This question, as fascinating as it is ambitious, has pushed scientists to undertake an investigation of unprecedented scale. The result, at the crossroads of figures and biology, could well redefine our perception of these insects which silently shape our ecosystems.

A colossal number of ants in the world

In 2022, a study published in the journal Proceedings of the National Academy of Sciences, relayed by IFLScience, revealed a striking estimate. The Earth is home to around 20 quadrillion ants. This conclusion is the result of painstaking work compiling data from nearly 500 studies on insect biodiversity across continents, biomes, and various types of habitats.

This estimate far exceeds that of 1994, the first scientific attempt at quantification, which was based on a simple extrapolation from data from the south-east of England.

The current methodology, by integrating a wider and more diverse range of data, offers a more global and precise view. It also highlights gaps, particularly in regions such as Asia and Africa, where data remains limited.

To visualize this monumental figure, imagine 2.5 million ants for every human being on Earth. A dizzying perspective which testifies to their incredible omnipresence.

Biomass of impressive proportions

Beyond the impressive number of ants in the world, their overall weight is also remarkable. According to the researchers, these 20 quadrillion individuals total a biomass of approximately 12 megatons of dry carbon, which is equivalent to 20% of human biomass. To put this into perspective, this weight corresponds to the total biomass of domestic poultry, such as chickens.

But their impact does not stop there. A 2023 study shows an impressive data: all terrestrial insects and arthropods combined reach a weight of one billion tonnes. This far exceeds the human biomass, estimated at 400 million tonnes, and that of livestock, close to 600 million.

This superiority in biomass underlines their crucial role in ecosystems. Insects, especially ants, are essential for recycling organic materials. They enrich the soil and help regulate populations of harmful insects.

An exceptional and unevenly documented diversity

Ants are also notable for their extraordinary diversity. Currently, scientists have recorded more than 15,700 species and subspecies. However, this number could be twice as high if still unknown species are included. These insects are capable of adapting to a wide variety of ecosystems and climatic conditions, which explains their presence on all continents, with the notable exception of Antarctica.

Certain regions, such as tropical forests and savannahs, concentrate almost two thirds of known species. These ecosystems rich in natural resources offer ideal conditions for their development.

However, entire areas of the globe, particularly in Asia and Africa, remain understudied. This means that our current knowledge of ant biodiversity is still partial and that many species remain to be discovered.

The geographic distribution of ants also reflects complex ecological dynamics. For example, some isolated islands, such as Iceland or parts of Eastern Polynesia, do not support any native species. These areas offer a unique insight into how ants spread and adapted over millennia.

The evolution of ants

Ants are not only numerous and varied, they are also ancient. According to a 2006 study, they date back to a period between 140 and 168 million years ago, during the Jurassic. This era, marked by a hot and humid climate, favored the emergence of many forms of life, including dinosaurs and the first flowering plants.

The appearance of flowering plants, in particular, played a determining role in the evolution of ants. The latter were able to exploit the new food sources offered by these plants, which favored their diversification. Since then, ants have evolved to adapt to a wide variety of ecological niches, developing complex social behaviors and symbiotic relationships with other species.

This remarkable evolutionary history partly explains their current success. They have survived major climate changes and ecological upheavals, becoming one of the most successful insect lineages in Earth's history.