Cellar Spiders will hunt Woodlice who like the damp environment of bathrooms
Nature on our doorsteps: A spider-eating spider
Rosaleen Dwyer is the County Heritage Officer at South Dublin County Council – every week she gives us an insight into the natural heritage around us and the beautiful biodiversity of the plants and creatures
One of the long-legged spiders that can often be seen in sheds and houses is the Cellar Spider.
While this spider’s body measures less than 1 cm, its legs can grow as long as 6 cm.
This gives rise to its other more commonly used name, the Daddy Longlegs.
Its body is a very light grey brown, and its long legs are almost transparent with darker spots at the joints.
Its long legs and soft colour give the spider a very light and airy appearance.
This species generally does not like to live outdoors in our cool Irish climate.
Instead, it prefers sheds, cellars, caves, and more especially, warm houses.
It makes irregular-shaped wispy webs in corners close to the ceiling from which the spider hangs upside down.
If it feels threatened, it has an interesting technique to defend itself.
It clings on tight to its web with its long legs and it begins to swing its body around in a circle at top speed.
This Cellar Spider has caught and wrapped a juvenile House Spider
This rapid twirling movement makes the spider almost invisible, and this confuses the potential attacker.
The Cellar Spider’s webs are not sticky.
While some prey simply wander into the web and become entangled in the dense mesh, Cellar spiders mostly leave the web to hunt for insects and other creatures like woodlice.
They will also feed on other spiders, even their own kind when food is scarce.
It often catches the larger bodied brown House Spider by throwing out silky threads to subdue it, before biting it and injecting venom into its body.
The Cellar Spider will also invade other spiders’ webs. It delicately taps the prey’s web, drawing the web’s owner out to investigate.
When it comes close enough, the Cellar Spider stretches up on its long legs to avoid being bitten and it shoots its own silky threads over the other spider before biting it.
In some parts of the world, the Cellar Spider is considered a beneficial species because it preys on poisonous spiders.
