As if spiders weren't terrifying enough, a study has shown that they eat twice as much the amount of food that humans do. Scientists have long thought that spiders are an important part of keeping pests under control, and now there's proof.
Many people are terrified of these eight-legged creepers. After all, they do look terrifying. Now we know that they collectively eat more than we, or even whales, eat. If that makes them even more terrifying, it actually shouldn't. This is evidence that the spider population plays an important role in global ecology.
Each year, the creepy crawlies consume 400 million to 800 million tonnes of prey. That's more than what humans eat, which is about 400 million tonnes of meat and fish. Seabirds, meanwhile, eat 70 million tonnes. Whales, the largest marine mammals on earth, eat just 280 million to 500 million tonnes of food a year.
A new study by researchers at the University of Basel and Lund University has detailed the new findings in the journal The Science of Nature. The researchers collated various studies and came up with an estimate of how many spiders crawl the earth. There are over 4,500 known spider species in the world, which collectively weigh around 25 million tonnes. There are more of them in forests and grasslands than in urban areas and other kinds of habitats.
The researchers also looked into data on the amount of food a spider needs to survive. They observed how the little predators capture prey and eat in the wild. Interestingly, the spider population in forests and grasslands contributed almost 95% of the total amount of yearly prey. Spiders in places like agricultural fields don't contribute nearly as much. This may be because areas like these have already been “disturbed” by heavy human activities.
The researchers were able to calculate how much the global spider population eats by calculating the biomass of their prey. A spider has a diet consisting mainly of insects, a lot of which are pests. Disease-carrying insects are also fair game. Interestingly, scientists have also observed that a spider may also feast on small mammals, fish, lizards, and frogs.
Therefore, these little eight-legged creatures contribute to keeping crops safe from pests and disease away from humans and other animals.
Aside from being prolific hunters, spiders are also an important food source for other predators. They feed up to 10,000 parasites and parasitoids, as well as up to 5,000 species of birds.
Thus, the spider plays a more important role in the greater scheme of things than we may think. If you're terrified of spiders, maybe this will help you think of them in a different light. They work behind the scenes to make sure that pests don't spread to other areas, or that diseases don't spread through insects. We can visualize a spider's effect on the planet by visualizing a small drop of water creating ripples on a liquid surface. For something so small, a spider makes quite an impact.
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