Yes, spiders are definitely present in Ireland. These arachnids are a natural and common component of the ecosystem across the island, just as they are in most other parts of the world. Ireland hosts a diverse array of species that thrive in various habitats.
Common Irish Spiders
Ireland is home to roughly 15 unique indigenous spider species, with a total of 583 species recorded through sightings. Among the most frequently encountered spiders is the Giant House Spider (Tegenaria atrica), an arachnid that can measure up to 120mm including leg span. These spiders often have a tan-colored abdomen featuring a herringbone pattern and are commonly found indoors, especially from September onwards as they seek warmth and mates.
Another common resident is the European Garden Spider (Araneus diadematus), also known as the Cross Orbweaver. These spiders are widespread in gardens, hedgerows, and near human structures, often identified by the distinct white cross marking on their reddish-brown backs. Cellar spiders (Pholcus phalangioides), frequently referred to as “daddy long-legs spiders,” are also very common indoors. They are recognized by their pale yellow to light brown bodies and exceptionally long, thin legs, constructing messy, irregular webs in corners. These spiders can sometimes prey on other spiders, including larger house spiders.
The False Widow spider (Steatoda nobilis) has become increasingly prevalent across Ireland since its first reported sighting in the late 1990s. These spiders, originally from the Canary Islands and Madeira, have successfully established themselves, particularly in urban areas, and resemble the black widow but are generally less venomous. Other species you might encounter include the Lace Web spider, which often retreats indoors during autumn, and the Zebra Jumping Spider, identifiable by its black and white markings and jerky movement.
Venom and Safety
While nearly all spiders possess venom, the vast majority of Irish spider species pose no significant threat to humans. Indigenous Irish spiders are considered harmless, and bites are rare. When bites from common species do happen, they are typically mild, often described as causing no more discomfort than a bee or wasp sting.
The Noble False Widow spider, an invasive species, has garnered attention for its bite, which can be more potent than those of native species. Symptoms from a False Widow bite can range from localized pain and swelling to, in some cases, more severe reactions like nausea, tremors, or persistent limb stiffness, occasionally requiring medical attention. However, these spiders typically only bite defensively if they feel threatened or are accidentally squeezed or trapped against the skin. Studies indicate that while its venom shares some toxins with the Black Widow, it is considerably less potent.
Spider Encounters in Ireland
Spiders are common in Ireland, inhabiting a wide range of environments from natural outdoor spaces to human dwellings. Common outdoor habitats include gardens, sheds, hedgerows, and wooded areas, where species like the European Garden Spider and Lace Web spiders are frequently found. Indoors, particularly in homes, you might encounter Giant House Spiders and Cellar Spiders in corners, basements, attics, and garages, especially as the weather cools.
Spiders often seek the warmth and shelter of houses during colder months or mating season, which typically runs from mid-August until early October. While spiders are present year-round, increased sightings indoors during autumn are common as male spiders become more active in their search for mates. Most spiders are reclusive and generally avoid human interaction, preferring undisturbed areas.