The bizarre world of ants – DW – 10/28/2024

Ants are found all over the world, on every continent except Antarctica.

Scientists estimate that there are currently about 20 quadrillion such individuals roaming the Earth. That’s 2.5 million ants for every person. If you were to weigh all these ants, they would weigh more than all the wild birds and mammals in the world combined.

That’s a lot of ants. And although they are tiny, they can have a big impact on the environment in which they live.

“Ants have fascinated people for a long time,” says Jack Longino, a biology professor at the University of Utah. “They are as diverse and crazy as the mammals of the Serengeti, these wild and crazy looking creatures.”

Ants can wage war, tend their own gardens and keep livestock. But this is just the beginning. Here are some more interesting facts about these tiny creatures that you may not know.

Ants have superpowers

The ant world is incredibly diverse. There are over 15,000 known species on the planet, and they have all evolved different skills in their habitats.

Ants can live in soil, on trees, underground, in leaves, in deserts and in cities.

Small insects are critical to healthy ecosystems. They agitate the soil, making it more fertile, and disperse seeds, helping to support plant systems. They can be predators as well as food for other insects and birds.

“Ants are nature’s engineers and gardeners,” says Tanya Latty, an entomologist at the University of Sydney in Australia. “Ants do so many different jobs in the ecosystem that it would be terrible without them.”

They’ve also developed some pretty cool abilities, almost like superpowers. Take the incredibly fast Saharan silver ant. It can move 100 body lengths per second, which is similar to a human running at 200 meters per second. And it’s not just about speed – they are also very strong: some ants can even carry weight 50 times their own.

How does an ant colony function?

Ants are social insects. They usually live in colonies, the numbers of which can vary from a couple of hundred to millions. To keep all these individuals alive and nourished, the colony works like a well-oiled machine.

Each ant performs specific roles for the benefit of the group. There may be one queen or several queens whose job is to reproduce. All other ants are female workers, tasked with caring for eggs and larvae, foraging for food, digging out the nest, and protecting it from danger.

Male ants have a short life and only one task: to mate with the queen.

To communicate in their huge colonies, ants constantly touch each other with their front antennae, or antennae. They also use chemical signals to lead their colleagues to tasty food or to warn them of danger.

Farm ants herding insects

Some ants earn their living by farming. Leaf-cutter ants are a famous example. These herbivores are known for walking in rows, carrying small pieces of leaves above their heads that look like mini umbrellas. But instead of eating those leaves in the nest, they turn them into compost to grow fungus. And it is this mushroom that becomes their food. Some leafcutter ants build huge colonies in tropical South America with thousands of underground mushroom gardens.

Many ant species have also developed special relationships with other insects, such as aphids, which produce sugar ants that love to eat. Ants tend these sap-sucking insects like cattle, essentially “milking” them for sweet honeydew.

“For some of these colonies, this may be the main source of carbohydrates. So they are very important,” says Lettie. In turn, “they will take care to protect their small herds of sugar cows from predators.”

What are supercolonies?

Some ant species form supercolonies, which can have many nests connected over a large area. The largest known supercolony belongs to the so-called Argentine ants and stretches 6,000 kilometers (3,728 miles) from northern Italy through France and southern Spain to Portugal. Native to South America, Argentine ants now live throughout the world.

Many invasive ant species are capable of forming supercolonies. Lettie says because they can reproduce quickly and produce thousands of queens, they are difficult to eradicate.

This can cause problems, as invasive ants can damage infrastructure, attack livestock and crops, sting people, and invade homes. If an invasive species takes hold, it can also displace native ants and other insects, changing ecosystem dynamics.

When an aggressive yellow crazy ant took over Australia’s Christmas Island, it killed millions of the iconic migrating red crabs by spraying them with formic acid. As a result, the island’s landscape has changed: vegetation has sprouted from forested areas once cleared by crabs.

The number of ant species considered invasive is increasing due to globalization and increased trade. According to scientists, more than 500 species of ants have been discovered outside their natural range. About 20 of these species are considered particularly invasive, meaning they have negative environmental and economic impacts. Invasive ants caused $51 billion in economic losses between 1930 and 2021.

Climate change, habitat loss and other threats

Human behavior is driving the loss of biodiversity around the world. This also affects ants, despite their large numbers.

The spread of invasive species, human-caused climate change, and habitat destruction are all potential threats to ants.

“Some (ants) have very small colonies. Some of them have very close relationships with specific plants. And if these interactions go awry, we will lose this species,” says Lettie.

Climate change could also lead to an even greater proliferation of invasive species, providing new opportunities to displace or eliminate native ants, says Cleo Bertelsmeier, an ant ecologist at the University of Lausanne.

“Many ant species come from the tropics, subtropics and the Mediterranean. And it will be much easier for these species to penetrate into temperate places in Europe such as Switzerland, Germany, northern France,” she says.

Changing habitats and rising temperatures are also a concern, says Jack Longino of the University of Utah. As the planet continues to warm from burning fossil fuels, the outlook is not good for ants that have adapted to higher, colder altitudes, he said.

“They will run away from the top of the mountain, they will have nowhere to go.”

Editor: Anke Rasper

Sources:

Abundance, biomass and distribution of ants on Earth, published in PNAS.

https://www.pnas.org/doi/abs/10.1073/pnas.2201550119

Economic costs of invasive alien ants worldwide, published in the journal Biological Invasions.

https://link.springer.com/article/10.1007/s10530-022-02791-w

Global dispersal and invasion capabilities of alien ants published in Current Biology https://www.sciencedirect.com/science/article/pii/S0960982222019200.

You can listen to the full episode about ants on the Living Planet podcast here..