When neat burrows with two entrances 10-15 cm apart are found these are more likely to be occupied by crickets than spiders.

The entrances to ant nests in the ground often have a surface cone of excavated soil and ants can usually be seen using the burrow. However, some burrow-dwelling spiders, including funnel-webs, also pile excavated soil on the down-hill side of their burrow after a period of rain has softened the soil.

Some moth caterpillars make densely webbed masses in green vegetation. The larvae of certain insect species also lay down webbing in masses of decaying plant material (including leaf litter) then make pupal cases that look like a spider's egg sac. The webbing produced at the bases of some gum trees by Symphyta larvae and some tiny white ant species is also remarkably similar to the webs of certain spiders.

What looks like spider's web may sometimes be seen on damp organic matter, including leaf litter, but has actually been made by fungi and is correctly known as a mycelium.

Weblike white areas that are sometimes found on domestic lawns are also due to fungal species and usually appear as expanding rings not as a solid areas of webbing.

Not many spider species lay unprotected egg masses so eggs not enclosed in webbing of any kind are more likely to have been laid by an insect than by a spider. Pholcid spiders are a notable exception, the females carrying their eggs around with only a few strands of silk holding them in place. Neuropteran (lacewing) insects produce single eggs (or U-shaped rows of eggs) on stalks but these hatch very quickly and the life cycle of these insects is very short when compared with that for most spiders.

Some insects lay batches of eggs encased in white material but this probably will not look like spider silk and presumably serves to impede desiccation of the eggs. A good example of this is the white egg patch of the common hemipteran planthopper that typically lays its eggs on smooth tree trunks.