Phototaxis

Phototaxis is a kind of taxis, or locomotory movement, that occurs when a whole organism moves towards or away from a stimulus of light. This is advantageous for phototrophic organisms as they can orient themselves most efficiently to receive light for photosynthesis. Phototaxis is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite.

Phototaxis has been described in microorganisms and algea, insects and other invertebrates, and vertebrates. Typically nocturnal insects can show positive phototaxis, while nocturnal mammals often show negative phototaxis.