Tube Spiders

Details

Tube spiders is a common name for spiders that build tube-like silken retreatsin cracks, under stones or behind bark and then wait at the entrance to ambush passing prey. In arachnology the term most often refers to tube-web or tube-dwelling spiders in families such asSegestriidae, so this article treats “tube spiders” as a general group of spiders with this lifestyle.

Basic Biology

• Representative taxonomic scope: Mainly family Segestriidae and related tube-dwelling spiders

• Common English names: Tube Spiders, Tube-web Spiders

• Body size: Typically medium to small ground spiders, about 8–20 mm in body length, with some species      reaching slightly larger sizes.

• Life span: Many species live around 1–3 years, with females often occupying the same tube retreat for      long periods.

Appearance

The appearance of tube spiders varies among species, but they share several general features:

• Body form: Moderately elongated bodies with well-developed legs, suited to rapid movement forwards and      backwards inside the silk tube;

• Colouration: Usually brown, grey-brown or dark brown with subtle markings that blend in with bark, rock      or masonry;

• Eye arrangement: Many tube-web spiders have characteristic eye patterns (in Segestriidae often six or      eight eyes in a curved or horseshoe-shaped row);

• Silk tube: A tubular or sac-like silken retreat built in a crack, beneath stones or behind bark, with the      front end at the surface and silk lines extending outward as “trip wires”.

Unlike orb-weavers that rely on large aerial webs, tube spiders behave more like “doorstep ambush predators”, rarely leaving the immediate area of their retreat.

Tube Retreats & Hunting Strategy

The name “tube spiders” comes from their tube-shaped silk retreats. A typical tube spider constructs a silk-lined tunnel in a narrow crevice:

• The inner walls of the tube are reinforced with layers of silk, making a durable shelter;

• Short strands of silk extend from the entrance across the surrounding rock or bark, acting as trip lines;

• During the day the spider usually stays deep inside the tube, while at night it rests near the entrance with its front legs      touching the signal threads.

When an insect or other small arthropod touches these trip lines, vibrations travel back to the spider. It then rushes out of the tube, grabs the prey with its front legs and fangs, and drags it back into the retreat to feed.

Distribution & Habitat

Tube spiders occur in many temperate and subtropical regions around the world. They are recorded from Europe, Asia, the Americas and Australia, with some related tube-dwelling species also present in tropical forests and montane habitats.

They are typically found in:

• Rock piles, stone walls, retaining walls and crevices in old buildings;

• Cracks in tree trunks, beneath loose bark and in cavities within fallen logs;

• Gaps between garden stones, steps and edging in parks and backyards;

• Occasionally in gaps on balconies, fences or under eaves around houses.

These spiders prefer shaded, sheltered and slightly humid microhabitats close to the ground, which are also favoured by many of the insects they hunt.

Diet & Ecological Role

Tube spiders are classic sit-and-wait predators. Their diet usually includes:

• Ants, beetles, small cockroaches and other ground-dwelling insects;

• Other spiders and a variety of small arthropods that pass near the tube entrance;

• Occasionally small vertebrates of similar size, such as tiny lizards or frogs, in the case of larger species.

By preying on many ground-dwelling invertebrates in cracks and stone piles, tube spiders contribute to natural pest controland are important predators in nocturnal arthropod communities.

Venom & Human Significance

Most tube spiders have venom that is effective on insect prey but mild to humans. Documented bites are relatively rare, as these spiders tend to stay within their retreats and do not actively roam indoors.

Reported bites generally cause only local pain, slight swelling or itching. Standard advice is to wash the area, apply a cold compress if needed and seek medical attention if symptoms are severe, persistent or occur in children or allergy-prone individuals.

Interactions with People

Tube spiders are unobtrusive residents of walls, rocks and tree trunks, and they seldom come into direct contact with people. In gardens and urban green spaces they act as quiet allies, helping to reduce numbers of insects and other small arthropods.

If a tube retreat is found in a place where it causes concern, the structure (stone, piece of bark, etc.) can be carefully moved to a more suitable location in the garden rather than using insecticides, which also protects other beneficial invertebrates。