20 quadrillion ants live on Earth, new study estimates
Scientists believe there are about 20 quadrillion ants on Earth, according to a conservative estimate published in an academic journal this week.
University of Gloucestershire entomologist and ant stan Adam Hart says the biomass of all the ants on Earth would surpass that of all wild mammals and birds. The ant population would weigh 20% of the weight of all humans on the planet.
Scientists looked at the more than 500 studies on different types of ant populations in ecosystems around the world to form the estimate, Hart says.
“Every ant species we know is highly social. So when you find a worker ant walking around on the pavement or whatever and you follow it, it will take you back to a nest,” Hart says. “And in some species, those nests can be huge.”
Leafcutter ants in South America can reach a population of 8 million — and driver ant colonies in Africa can exceed 20 million, he says. These organized ant societies do complex work, which makes them an important part of ecosystems.
Ants aerate soil and help recycle nutrients by bringing materials down from the surface, Hart explains. The teeny creatures are also predators who prey on animals humans consider pests and increase biodiversity.
“If we think of insects as the glue that holds the ecosystem together, ants are almost kind of the super glue,” he says. “They’re involved in all kinds of different interactions that are of real significance.”
A few ant species use Earth’s magnetic field to navigate. Researchers are starting to understand the “tiny magnetic crystals” in ants’ brains that interact with the nervous system to direct them, Hart says.
“I guess in a sense you could say that ants have an inbuilt GPS system, which is at least as sophisticated as anything that we’ve come across in the natural world,” he says. “They are quite remarkable.”
Gabrielle Healy produced and edited this interview for broadcast with Jill Ryan. Allison Hagan adapted it for the web.
This article was originally published on WBUR.org.
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