What is the typical form and function of the silk structure spun by Yellow Sac Spiders?
Small, silken tubes or sacs spun in sheltered locations for daytime resting.
The common name 'Yellow Sac Spider' directly refers to the structure they create, which is notably different from the expansive capture webs built by orb-weavers. Instead of large capture webs, these spiders construct small, silken retreats or sacs. These retreats are typically spun in secluded areas, such as under rocks, within leaf litter, or tucked away in structural corners inside buildings. The silk used creates an opaque tube dense enough to completely conceal the spider during the day while it rests. The size of this day retreat directly corresponds to the spider's body size; for instance, a mature female's sac is often around half an inch long, offering camouflage from overhead predators.
