Light has the power to blind and to harden. There are certain animals which come out only at night, in the dark-raccoons, for example. If you shine a light on them they scurry away. They do not want to be exposed. Some insects are the same way.
Cockroaches love the darkness.
As soon as they are exposed to the light they run for cover. Some men are that way, too. Thieves do not like to work in the light. They want darkness. If a policeman comes in the night and shines his spotlight as the thief is breaking into a house, the thief runs off.