By Roshni D’Souza
Researchers at the University of Galway published a study recording the first sighting of a noble false widow spider feeding on a pygmy shrew. The study was published in the “Ecosphere,”an international environmental journal.
Dr Michel Dugon and Dr John Dunbar from the Venom Systems Lab in the Ryan Institute at the University of Galway published the study.
“The noble false widow is a very intriguing spider, and we have much to learn about it still. We are very grateful to the members of the public who share their observations with us. This allows us to understand better how this invasive species may impact us and our environment,” said Dr Dunbar in a public statement.
Dawn Sturgess sighted the spider eating the shrew in Chichester, West Sussex, England.
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The Importance of the finding
The research team, led by Dr Dugon, has been studying the species for the past seven years. In 2018, they sighted the noble false widow spider eating a gecko larger than the pygmy shrew.
In an interview with The Galway Pulse, Dr Dugon said that the study helps them understand why the spider is doing so well outside its natural habitat.
The origins of the noble false widow are in the Canary and Madeira Islands, “yet it seems to do amazingly well, in the cooler and wetter climate of Ireland and the UK” according to Dr Dugon.
“A pygmy shrew is about 10 times heavier than a noble false widow. To capture such a large prey, the spider uses spring-loaded silk threads attached to the closest surfaces. When a prey brushes against the silk thread, it detaches itself and move upward, hoisting the prey with it.”
This is only the third sighting of the false noble widow preying on a vertebrate animal, although the spider is a habitual vertebrate eater.
Dr Dugon said that a habitual vertebrate eater “doesn’t mean that they eat vertebrates every other day” as spiders can survive months without any food, but rather “vertebrate captures are not just accidental, but the result of active predation events.”
“Observing an invasive species feeding on three types of vertebrates over a couple of years is a pretty big thing and shows that these predation events are not just accidental,” he added.
According to Dr Dugon, there’s a lot more to explore with the noble false widow in terms of how the spider is surviving in a climate which it is not native to .
The Venom Research Lab that Dr Dugon heads is also looking at the impact the species has on native species, including vertebrates and arthropods — more commonly known as bug species.
“We are currently measuring this impact by quantifying the density and diversity of native species in relation to the presence or absence of the noble false widow in various habitats,” Dugon said.