Israeli scientists calculate the total weight of all insects on Earth – study

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Arthropods work as “ecosystem engineers” and their absence would be a disaster. They pollinate our crops and cultivate agricultural soils, while being food for many species of animals. about their numbers and weight.

Researchers at the Weizmann Institute of Science in Rehovot have taken a significant step towards answering these questions. In a study published in the journal Science Advances, a team led by Professor Ron Milo in Weizmann's Department of Environmental Sciences estimated that the total biomass of terrestrial arthropods is about one billion tons, which is roughly equal to the biomass of all humans – about 400 tons – and farm animals – about 600 million tons – combined.

“Insects are called “little creatures that rule the world” due to their important role in many ecological processes. We must take them into account if we want to fully understand the impact of humanity on the planet and the possible consequences of climate change, – says Dr. Yuval Rosenberg, co-author of the study. “Quantification of arthropod populations establishes a baseline against which we can measure future changes in arthropod communities and how these changes, in turn, may affect global processes.”

The researchers collected data from thousands of observations over many years in about 500 biomes, from rainforests to deserts and farmlands. The study shows that the bulk of the biomass of terrestrial arthropods belongs to creatures living underground, which are critical to the ecology of the underworld. Underground arthropods are responsible for the processes that fertilize the soil and affect the global carbon cycle. They prey on other organisms, maintaining the ecological balance.

Researchers have calculated that the number of individual arthropods underground is about 10 quintillion, or 10 billion billion.
Insects living in colonies make up half the mass of underground arthropods, termites and ants make up 40% and 10% of this category, respectively. Most of the aboveground arthropod biomass is found in rainforests and includes many familiar arthropods such as butterflies, ants, beetles, grasshoppers and spiders.

According to Rosenberg, species with a large number of individuals or a large collective weight usually have a greater impact than rare species. Quantifying the mass of arthropods helps develop a more up-to-date perspective on ecological processes and contributes to a holistic understanding of the role of arthropods in global ecology. Arthropods are highly influenced by humans and climate, which in turn makes our ecological systems vulnerable, for example, that on agricultural land they are much less than in forests and forests in the same climatic zone.

“The health of our ecological systems largely depends on the state of arthropod populations. Thousands of species of birds, reptiles, and amphibians depend on them for food, and arthropods help decompose and recycle dead plants and animals, as well as their excrement, – explains Dr. Rosenberg. “A broad quantitative approach can help us assess how our ecological systems may change and how this may affect our health, economy, agriculture and quality of life”.

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