Invasive spider caught trapping and feeding on protected bat species

The pipistrelle bat is also found in Canada.

Originating from Madeira and the Canary Islands, the noble false widow spider was first spotted in the UK in 1879, believed to have arrived via banana boxes sent over from the Canary Islands. Since then, its population has grown and spread, both in England and globally, reported in East Asia, North America, and South America.

Considered one of the most invasive spider species on the planet, scientists are still trying to determine the ecological impact of false noble spiders, but a new report by researchers from the Ryan Institute in NUI Galway suggests their presence is detrimental to at least some native species.

In a world first, scientists have published a record of a noble false widow spider trapping and feeding on pipistrelle bats in a UK attic.

"A member of the public actually noticed a bat being entangled in a web in a house in the UK and posted a picture on social media, and my postdoc John Dunbar contacted the person ... and we understood very quickly that this was a first," Dr. Michel Dugon, the senior author on a new paper documenting the find said in a video about the study.

Steatoda nobilis France source-Wikipedia

A false nobel spider (Alexis Lours/Wikipedia CC BY 4.0

"What's interesting here is the spider actually set its web just below the bat roost, and so young bats that are trying to fly, have the possibility [of falling] on the web."

Researchers say they have never seen a member of this family of spiders (Theridiidae) preying on a bat anywhere in the world, and it has never been observed preying on a vertebrate in Britain.

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It is the first time a member of this family of spiders, called Theridiidae, has been recorded preying on a bat anywhere in the world or any vertebrate in Britain, but the spider feeds on lizards elsewhere.

Pipistrelle bats are small, with adults measuring between 3.5 and 4.5 centimetres long. The bats caught up in the web in the study were a pup, which was deceased, and a "much larger adult bat" which was alive and entangled. That bat was rescued and released.

In humans, false noble spider bite can cause symptoms ranging from mild to severe cases that may require hospitalization.

While false noble spiders are not in Canada, pipistrelle bats occur in New Brunswick, Nova Scotia, Quebec, and Ontario.