Net-casting spiders (genus Deinopis) have a remarkable—albeit unorthodox—hunting technique. By day, they hide stick-like among the brambles and branches of eastern Australian forests, and by night, they build silken webs the size and shape of postage stamps.
To catch their prey, the spiders create a silk frame amid low branches of vegetation, filling it in with an elastic silk from its cribellum—a silk-spinning organ covered in thousands of tiny spigots. These spigots produce extremely thin fibers that the spider combs with specialized leg bristles called calamistrum. The bands of silk are so fine and elastic that prey are entangled in them without the need for a sticky substance.
Upon completing its web, the spider deposits specks of white feces on the ground as a target point for prey. Hanging head first from a thread of silk, the spider holds the net between its front pair of legs and patiently waits.
With large marble eyes that have compound lenses, their night vision can concentrate light more efficiently than a cat or an owl. The moment an insect passes over the white specks, the spider expands the web to double or triple its resting size and plunges the net on top of unsuspecting prey. The insect is subsequently paralyzed, wrapped, and dinner is ready to be eaten.
GIF via Imgur: http://i.imgur.com/k6qocD6.gif
Watch a video of the spider in action below.