Researchers find spiders eat up to 800 million tons of prey annually

Researchers have revealed that spiders consume up to 800 million tons of prey every year.

This figure may seem even more surprising when compared with the fact that all of the humans on Earth consume about 400 million tons of meat and fish each year, according to the United Nations Food and Agriculture Organisation.

Spiders mostly consume insects but the largest tropical species occasionally make a meal of vertebrates such as frogs, lizards, fish and small mammals, say experts.

Over 45,000 species of spider live across the world and have a collective weight of about 25 million tons.

A team of Swiss and Swedish scientists calculated that collectively the spiders kill between 400 million and 800 million tons of prey annually,

The appetite of spiders even exceeds that of whales, which consume an estimated 280 million to 500 million tons of prey a year.

Lead researcher Dr Martin Nyffeler, from the University of Basel in Switzerland, said: "Our calculations let us quantify for the first time on a global scale that spiders are major natural enemies of insects.

"In concert with other insectivorous animals such as ants and birds, they help to reduce the population densities of insects significantly,.

"Spiders thus make an essential contribution to maintaining the ecological balance of nature."

Ninety per cent of spider prey consists of insects and springtails, small insect-like arthropods, the study published in the journal The Science of Nature found.

The team showed that spiders killed many times more insects in forests and grasslands than in other habitats.

Their impact was lower in agricultural areas because intensively managed farmland is not favourable to spiders, said the researchers.