klinotaxis

Klinotaxis is a type of directional orientation in zoology where an organism turns toward a stimulus. This involves a process of comparing stimulus intensities between different positions to make a "choice" about direction.12

This behavior is achieved through alternate lateral movements of the body or a body part. Animals with a single sensory receptor, such as Euglena, earthworms, and fly larvae, often exhibit klinotaxis. For example, a blowfly maggot moving away from light swings its head left and right, presumably using a light receptor on its head to determine direction based on changing light intensities. This response is more common with chemical stimuli than light.2