The Weight Loss Quest in Tampa The Black Widow Spider usually preys on other insects, nevertheless they will occasionally go after other spiders, woodlice, chilopods and diplopods too. Most of their prey is captured after they become entangled in the webs of the black widow spider as soon as they are willing to feast upon the prey they bite them to inject the venom then hold them tightly for your approximate ten mins it takes for that venom to look at effect. Once their prey is dead they take it to their retreat and then feed on it.