|Kleptoparasites feed on the prey or collected food of others other organisms. Stealing the prey of others is not so common in insects. However, the tiny Milichiidae feed on body fluids of the prey of spiders. More common in insects is the theft of food provided to the larvae. Perhaps this may be a law in ecology: as soon as one organism predictably hoards food, there are kleptoparasites to take advantage of the collected food. Often the kleptoparasite is a species closely related to its host, as in various bees; but this need not be true, as in the Miltogramminid flies (Sarcophagidae), which are kleptoparasites of various digger wasps or bees.