GabyThe total mass of all arthropods on Earth—about one billion tons—slightly exceeds the combined weight of all humans and agricultural animals, researchers at the Weizmann Institute of Science in Rehovot found.
Arthropods include insects, crustaceans, arachnids, and myriapods.
Without these little creatures that buzz, flutter, run, and crawl, the world would be very different. They play essential roles across the biosphere. Dr. Yuval Rosenberg, one of the study’s authors, called them “tiny beings that govern the world.”
After calculating global totals, the team made a surprising discovery. Despite their small size, arthropods’ combined mass slightly exceeds the mass of Earth’s human population plus livestock (people weigh about 400 million tons worldwide, while livestock weigh about 600 million tons).
Arthropods — fighters against global warming
The study’s conclusions are essential for understanding humanity’s impact on the planet and for predicting the likely consequences of climate change, Rosenberg said.
He and his colleagues analyzed 7,000 measurements from the scientific literature on arthropods. The data covered 300 sites worldwide across diverse terrestrial environments — farms, deserts, and tropical forests.
The team divided arthropods into ground-dwelling (including those in leaf litter) and above-ground (including plant-associated insects).
The data show that most arthropods live “tightly pressed against the skin of our planet or inside it,” and their combined mass is about one billion tons.
Termites make up about 40 percent of soil arthropod biomass. Ants are roughly 10 percent less abundant than termites, ScienceAlert reported.
Each square meter of the upper soil layer contains tens of thousands of arthropods, the vast majority of which are mites and springtails.
Just in and on the soil, about 10 quintillion organisms live (a quintillion is a 1 followed by 18 zeros). These small animals help recycle nutrients and play a role in the global carbon cycle.
Rosenberg emphasized that arthropods strongly influence vegetation. They feed many birds, reptiles, and amphibians, and they break down dead plants, animals, and waste. That decomposition fertilizes soil and helps limit disease outbreaks.
These results will help scientists understand how arthropods fit into ecosystems and predict the consequences if their populations decline under the climate crisis.
In a review for Science Advances, the authors say the quantitative assessment establishes a baseline to detect future changes in arthropod communities and to predict how those changes might affect the planet’s future.
