Ants fill a 150-year gap in biodiversity research

In the bustling world of biodiversity, ants have long been the missing piece in a puzzle we’ve been assembling for nearly 150 years.

While it’s a well-established fact that species distribution around the globe is influenced by a blend of evolutionary mechanisms and environmental factors, our understanding has been based exclusively on vertebrates and plants – until now.

These “little things that run the world” have finally taken center stage, revealing new insights into the biogeographic realms that shape life on Earth.

Biogeographic realms in biodiversity

The distribution of species around the globe is not a random process but an outcome of evolutionary mechanisms and environmental limitations, both past and present.

Since the mid-19th century, biologists have identified key regions, known as biogeographic realms, that depict these large ensembles of species around the world.

These realms represent one of the most fundamental descriptions of biodiversity on Earth and are commonly used across various biological fields.

Filling the insect knowledge gap

However, for nearly 150 years, the characterization of these biogeographic units has been based solely on vertebrates (e.g., birds, mammals) and plant groups.

These groups represent only a small fraction of Earth’s species, leaving hyperdiverse organisms like insects largely out of the picture.

This gap in knowledge has posed a significant challenge for conservation planning and understanding biodiversity distribution.

Mapping the biodiversity of ants

Recently, ecologists from The University of Hong Kong (HKU) and their collaborators in Japan took a major step to fill this gap by mapping the global biogeographic regions for ants.

This work, published in Nature Communications, provides the first comprehensive effort to include insects in such studies and offers new approaches to understanding their distribution. The study marks a significant milestone in global conservation efforts.

Ants: The little giants of biodiversity

Insects make up over 55% of all described species, yet the knowledge gap regarding their distribution has hindered scientists’ ability to map their biogeographic regions.

“A first step to protect species, and thus biodiversity, is to understand where those are located,” noted Professor Benoit Guénard, senior author of the study and head of the Insect Biodiversity and Biogeography Laboratory at HKU’s School of Biological Sciences (SBS).

To tackle this challenge, Professor Guénard has led an international team for more than a decade to assemble distribution data for nearly 16,000 ant species.

Ants are among the most widespread and ecologically dominant insects, with a combined mass that exceeds that of all wild birds and mammals, as shown in a previous study by Professor Guénard’s team.

First global biogeographic map of ants

For an insect group, ants are relatively well-documented. The team’s extensive work, compiling data from over 300 years of ant research, enabled them to use advanced techniques, including bioinformatics and machine learning, to predict and analyze their distribution.

This effort culminated in the creation of the first-ever biogeographic map of ants. The map reveals the division of ants’ global territory into nine large biogeographic realms.

“Interestingly, when I was comparing this map with those for vertebrates and plants, I saw so many similarities,” said study first author Runxi Wang, a PhD candidate in HKU’s School of Biological Sciences. “Ants and plants share several regions that are not found in vertebrates.”

Ecological relationship of ants and plants

Further analysis confirmed these observations – the biogeographic regions are strikingly similar across different taxa, but ants and plants share a closer resemblance than any vertebrate groups.

“It’s not very surprising because we know that ants and plants have very close ecological and evolutionary relationships,” explained Professor Guénard.

“For instance, ants help tens of thousands of plants to disperse their seeds and protect many more from herbivores. They have co-evolved for millions of years, but this is one of the first pieces of evidence showing such significant biogeographic consequences.”

Ants and future biodiversity research

The results of the study suggest that many similarities between animals and plants might not be captured by looking only at vertebrates.

“Ants alone cannot represent the hyperdiversity of all insects, but their similarities to plants are probably not an exception,” said Wang. “We certainly need greater efforts to include more insect groups in the future to depict the global picture of biodiversity.”

The full study was published in the journal Nature Communications.

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