Do spiders only eat gnats?

Although gnats are definitely on the spider's menu of preferred foods, their diet is by no means limited to gnats alone. Spiders are carnivorous and will eat whatever insects get caught in their webs, although some of the larger spiders are big enough to eat small birds and mice.

Four main techniques for capturing prey are used by spiders. Sedentary spiders create a silk-lined burrow where they hide until prey pass by; the spider then hops out and captures it. Active spiders ambush their prey by lying in wait under a stone, on tree bark or on a leaf until a meal happens by. There are also spider that hunt their prey. Nonetheless, most spiders weave a web and wait for their food to come to them.