Tube-web Spider Identification Guide
Identify a tube-web spider by its glossy dark body, long front legs, and silk-lined tube retreat in bark crevices or walls.
Read the full Tube-web Spider encyclopedia entry →
Key Visual Features
Tube-web spiders build a signature silk-lined tunnel retreat with trip-line threads radiating outward to detect prey.
- Size: Body length typically 8-20 mm depending on species, with a fairly elongated build.
- Color: Glossy dark brown to black or purplish-black, sometimes with a slight sheen on the abdomen.
- Body shape: Elongated cephalothorax and abdomen, giving the spider a somewhat cylindrical, streamlined look compared to bulkier hunting spiders.
- Eyes: Eight eyes, often arranged in two rows, though inconspicuous compared to the spider's other features.
- Legs: Eight legs, with the front two pairs notably long and often held forward, well-suited to quickly grabbing prey that trips the silk lines near the tube entrance.
- Web/retreat: A silken tube tucked into a bark crevice, wall crack, or gap between stones, with irregular trip-line threads radiating out from the entrance across the surrounding surface — this tube-and-trip-line combination is the clearest identification feature.
Where and When You'd See It
Tube-web spiders favor vertical surfaces with crevices, such as tree bark, stone walls, and the mortar lines of brick buildings. They are most active at night, remaining just inside the mouth of their tube during the day and darting out rapidly after dark when an insect brushes one of the trip-line threads. The silk tube itself can often be seen year-round, even when the spider is not visible.
Similar-Looking Bugs
- Lace weaver spiders: Also build a tube retreat, but their silk has a distinctly woolly, bluish texture from cribellate silk, unlike the smoother silk of a tube-web spider.
- Purseweb spiders: Build a similar-looking external silk tube, but purseweb spiders strike through the tube wall rather than emerging onto trip lines outside it.
- Funnel-web type spiders: Build a funnel-shaped sheet rather than a narrow cylindrical tube, with a broader entrance area.
Quick ID Checklist
- Glossy dark brown to black, elongated body
- Long front legs held forward near the retreat entrance
- Silk tube tucked into bark, wall, or stone crevices
- Trip-line threads radiating from the tube entrance
- Nocturnal, darting out quickly when prey contacts a trip line
Behavior Notes
The spider senses vibrations transmitted along the trip lines when an insect touches one, allowing it to rush from the tube, seize the prey, and retreat back inside within moments.
Frequently asked questions
What's the clearest sign of a tube-web spider's presence?
A silk-lined tube tucked into a crevice, with several irregular trip-line threads radiating out across the surrounding bark, wall, or stone surface.
How does a tube-web spider catch its prey?
It waits just inside the tube entrance and senses vibrations when an insect brushes one of the trip lines, then darts out to grab it before retreating back inside.
Where are tube-web spiders commonly found?
On vertical surfaces with crevices, such as tree bark, stone walls, and brick mortar lines, especially in sheltered spots.
How is a tube-web spider's retreat different from a lace weaver's?
Both build tube retreats, but a lace weaver's silk has a fluffy, woolly, bluish texture from cribellate silk, while a tube-web spider's silk is smoother.