As it happens5:21How many ants are there? The song is ‘incredibly hard to understand’
There are so many ants on the planet that the human brain can barely comprehend them, says the German insect ecologist who helped calculate the number.
In a new study published in the Proceedings of the National Academy of Sciencesa group of scientists examined data from 489 ant studies and used those findings to estimate the number of critters currently roaming the Earth.
The final total was 20 quadrillion. That’s 20 billion million, or 20,000,000,000,000,000 with 16 zeros. And it’s probably an underestimate.
“I am stunned,” said Sabine Nooten, an insect ecologist from the University of Würzburg and one of the lead authors of the study. As it happens host Nil Koksal. “It’s incredibly difficult to understand. It’s also amazingly wonderful.”
In other words, the combined biomass of the world’s ants is greater than that of all wild birds and non-human mammals combined. And while they are most common in tropical climates, they can be found in different habitats on every continent.
And they’re all out there doing their busy work, interrupting picnics and playing an important role in sustaining global ecosystems.
How did they do it?
To come up with their count, Nooten and her colleagues looked at hundreds of studies from around the world in different languages.
The studies themselves usually used one of two methods to calculate different ant populations. One is collecting samples of leaf litter: “This is very neat because you can use a square meter of forest floor, take all the leaf litter and take the ants out of this leaf litter. And then you count all the ants in this area and you can eventually scale up from this area and extrapolate to the global surface,” Nooten said.
The other is to use pitfalls for the ants and wait for them to fall in, and use those totals to extrapolate larger populations.
Aaron Fairweather, a doctoral student at the University of Guelph who studies ants and other insects, says the study’s methodology is “very impressive and sound” and its global scope is “a huge undertaking.”
“Understanding that there are trillions of ants on the planet is unbelievable and unfathomable. The fact that we have the resources to understand that is even more amazing,” they said.
“We are now beginning to glimpse what global ant life is like on the planet. That said, I think this is probably an underestimate of the total number of ants on the planet.”
That’s partly because existing methods for calculating ant populations are limited and can’t account for the critters that live underground and in vegetation, Fairweather said.
But it’s also because there are whole species of ants that have yet to be discovered.
Nooten says there are 12,000 known species of ants, or 16,000 if you break down all the subspecies, and “many more species are discovered every year.”
What’s so great about ants anyway?
So why do scientists want to know how many ants there are?
“While ants can sometimes be a real nuisance when they invade our kitchens or when they invade us during picnics outside in the parks, they are hugely important in the ecosystems where they exist,” Nooten said.
They help with nutrient cycleaerate the soil, spread seeds and decompose plant and carcass biomatter.
“So they do all these different functions out there. And without them, the ecosystems would look a lot different than they do now,” Nooten said.
“I think it’s very important for us when we go to the forest and go for a walk in the park or something, we don’t just appreciate the big animals that we see, like little fluffy mammals and birds, but we also have to take care of ourselves.” look beyond and look at the little things that actually power our ecosystems and help keep our ecosystems running and in check.”
Fairweather agrees, saying studying insect biomass can also help us better understand how our planet works, and monitor the effects of climate change.
“This is an extremely understudied area, but it’s incredibly important to monitor as the climate changes faster and faster. Contextualizing our impact on the planet with numbers, mass, individuals, that’s what gets more attention to the problem,” Fairweather said. .
It could also help us track insect populations over time, they said, and get a better idea of how many are lost to things like climate change, pesticide use, urbanization, agriculture, spread of invasive species and pollution.
In fact, Nooten says a good next step, in terms of research, would be: until map the ant population on a timeline to see how it has shifted. In follow-up studies, scientists could investigate whether they are increasing or decreasing in number.
Ants, she says, “do so many different, amazing things.” So the next time you feel the urge to crush one, she urges you to reconsider.
“If I see one at a picnic, I give it a crumb of cookie or something else to eat and see where it goes,” she said.