Scientists publish first record of false widow spider feeding on protected bat species

Scientists in Galway have released the first record of a noble false widow spider feeding on a protected species of bat in the UK. The new study, titled Webslinger Versus Dark Knight, published in the international journal Ecosphere, shows that false widow spiders continue to impact native species.

This is the first time a member of the spider family Theridiidae has been recorded hunting a bat anywhere in the world, or any vertebrate in the UK. The event also marks the first time a species of false widow spider has been recorded feeding on mammals.

The study of the noble false widowhood feeding on Pipistrelle bats has been published by scientists at the National University of Ireland in Galway. The discovery was made by wildlife artist Ben Waddams at his home in North Shropshire.

For two consecutive days, bats living in the attic were found entangled in the spider web under the entrance to the roost. The first bat, a young pup, was completely immobilized with its limbs pinned tightly to the torso with silk. It was slightly shriveled and discolored from the spider feeding on the remains.

A second, much larger adult bat was also captured and entangled in the web, but as it was still alive the bat was rescued and released.

In the UK, Pipistrelle bats are protected under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017.

The gruesome occurrence isn’t as rare as people might expect – three years ago the noble false widow spider was reported feeding on a protected species of lizard native to Ireland.

Native to Madeira and the Canary Islands, the noble false widow Steatoda nobilis has the potential to become one of the most invasive spider species in the world.

It was first recorded in southern England in 1879 and has increased its range and population density in recent decades, spreading north towards Scotland and east. west through Wales and Ireland. During this period, the species also spread worldwide from Europe, East Asia, North America and South America.

The species is known for its medical importance, having the ability to cause a range of mild to severe symptoms in those bitten, but little is known about its impact on native species.

Over the past five years, the team led by Dr Michel Dugon at the Ryan Institute at NUI Galway, has studied a wide range of species-specific characteristics, including its venom, symptoms after envenomation, ecology and behavior .

Dr Dugon, head of the Venom Systems Laboratory at the Ryan Institute, said: “We’ve been working on the noble false widow for five years and have learned a lot about this species – yet we’re still amazed at its ability to s “adapt to new environments and make the most of available resources. This is a truly remarkable species.”

Dr John Dunbar, Irish Research Council postdoctoral researcher at the Venom Systems Laboratory and lead author of the study, said: “In more exotic parts of the world, scientists are documenting such spider predation events on small vertebrates for many years, but we are only beginning to realize how frequently these events occur.

“Now that this exotic species is well established in Ireland and the UK, we are witnessing such fascinating events on our doorstep.

“Even other, much smaller, false widow species have been known to capture and feed on snakes and lizards. This study presents yet another example of the invasive impact of the noble false widow on native species. know that they are much more competitive than native spiders, and this further confirms their impact on prey species.”

He added: “Although the spider has been present in Ireland for over 20 years, we do not know what its impact on the environment and ecosystem is in terms of competition with native spiders or impact on the native prey species This is important as we are beginning to have a better idea and understanding of what prey he can handle.

“In this case, bats being vertebrates, the spider’s venom has a powerful neurotoxin and this allows it to take down vertebrate prey. This makes them much more competitive than native spiders. Some studies show that the Noble False Widow’s venom is significantly more potent than native spiders.”

He said the spider would not consume the entire bat, but would feed on it until the spider was full. Spiders possess a fast-acting neurotoxic venom with a composition very similar to true black widow spiders that can cause neuromuscular paralysis in terrestrial vertebrates, allowing them to occasionally feed on small reptiles and mammals.

Aiste Vitkauskaite, a researcher at the lab, said: “The false widow spiders, much like their close relatives the black widow spiders, have extraordinary prey-catching techniques and a remarkably potent venom that allows them to capture small vertebrate prey multiple times. larger than the spider itself with surprising ease.”

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