Dawn Sturges was looking out of her bedroom window in the south of England one day last summer, just in time to witness an arachnophobic nightmare: a shrew tangled in a spider’s web, poisoned by spiders. Shutting down the nerves of small mammals rapidly weakened the shrew’s ability to fight.
For the next 20 minutes, Sturges watches a female Noble False Widow spider lift an immobilized matchbox-sized dwarf shrew, many times larger than the spider, about 10 inches above the rafters of the house. Did. Liquefy and consume its food.
“I stood behind the window and watched for years,” Sturges, a citizen scientist, filmed the entire interaction on her phone. “I was fascinated by the spider’s strength and determination to bring home its prey!”
While this is the first confirmed case of noble false widow spiders devouring shrews in the UK, it is not the first time these voracious spiders have been seen taking down relatively large prey. According to recent information ecosphere In a study co-authored by Sturgess and researchers from the Venom Systems & Proteomics Lab at the University of Galway in Ireland, this is the third documented case of a noble spider spider preying on a vertebrate in the past five years. This suggests that small mammals such as the British protected shrew may be appearing on spider menus more frequently than previously thought.
Noble False Widow Spider (Steatoda nobilis) is native to the Canary Islands. They arrived in England in the 1870s after stowaways on ships carrying bananas and houseplants. The spiders then spread to mainland Europe and the Mediterranean, and eventually to South America and California. It can produce up to 1,000 offspring.
Another factor that contributes to their longevity is a versatile diet. John Dunbar, one of the Galway University researchers who led the new study, said noble spiders are known to eat a wide variety of arthropods, from flies and wasps to centipedes and other spiders. It states that The new find adds evidence that these spiders, which can reach up to half an inch in length, also hunt larger prey. In recent years, Dunbar’s team has seen common ground lizards and small bats tangled in the sticky webs of noble false widow spiders.
“The fact that this spider was able to lift a shrew ten times its size was truly amazing,” said the German Integrative Biologist, who published a 2020 literature review of vertebrate-eating arthropods. says Jose Valdez, an ecologist at the Center for Diversity Research. The ability to lift such large prey suggests that spiders may be well suited to hunting larger prey in their environment.
Many vertebrate-eating spiders are mammoths, at least in arthropod terms. A prime example is the Goliath bird-eating spider, the world’s largest spider. With legs up to 11 inches wide, this tarantula can turn into food for anything smaller than itself, including frogs, lizards, mice and, of course, birds.
Unlike the goliath birdeater, the much smaller noble false widow spider cannot muscle its prey out. Instead, it relies on a deadly combination of powerful silk and powerful poison. The spiders then inject a potent neurotoxin concoction that can paralyze small vertebrates such as pygmy shrews in minutes, says Dunbar.
Then it’s time to eat. The venom contains proteins that break down tissue, helping the spider to liquefy its diet by excreting digestive juices. In the case of the shrew, the only remains researchers found after three days were inedible fur, bones and skin.
Among noble spiders, only adult females have so far been observed feeding on vertebrates. This is probably because female spiders need to gather as much food-derived energy as possible in order to produce a staggering number of offspring.
“Vertebrates make great food for spiders, so they’ll attack if they get the chance,” says Witt Gibbons, a herpetologist at the University of Georgia. Gibbons published a study last year that found that about 30% of arachnids eat vertebrates. For example, a triangular cobweb spider (which comes from Eurasia and is a close relative of the noble false widow spider) has been observed subduing a garter snake weighing 355 times its own weight. . Similar-sized brown spiders have been successful in repelling rats. “I think spiders generally fall into one of the many animal categories associated with spiders. [with] Wider prey diversity than expected,” says Gibbons.
Noble spiders prefer large prey, but Dunbar doubts spiders pose a serious threat to vertebrates such as pygmy shrews. But he thinks it’s important to monitor what these his eight-legged aggressors are eating. “Other kinds of small vertebrates are very likely to fall prey to the noble false widow. [spiders] They continue to expand their reach,” he says. “It adds a new dimension to their invasiveness.”
