FLICKER FUSION
Certain animals have evolved specific sensory abilities much wider than our own...
Insects could never enjoy the illusion created by motion pictures, because they would see the distinct periods of darkness between the individual frames as they are projected; they can also see the 100 or 120 times each second that fluorescent lights grow dim, as well as the black bands that sweep across television screens 50 or 60 times each second. Animals with high flicker-fusion rates thus have a greater sensitivity to motion, probably a necessity for rapidly moving creatures like many insects.
Gould, James L. and Gould, Carol Grant (1994) The Animal Mind. Scientific American Library, New York.
Gould and Gould (2004: 13) note that the resolution of the human eye is superb. Only falcons and, perhaps cheetahs, with double foveas do better. Insects, with the notable exception of dragonflies, are "legally blind" as far as resolution is concerned but are supreme in the realm of flicker fusion. The rate is 200Hz in bees.
Flicker fusion is the frequency at which an intermittent light stimulus appears to be continuous. Silent movies were filmed at 16 frames per second. They appeared slightly jerky. Contemporary movies are usually shot at 24 fps. In theaters projectors double the rate to 48 Hz by showing each frame twice.