How does orthokinesis change an animal’s activity level?

Orthokinesis is a type of unoriented kinesis, which is a stereotyped response where an animal changes its activity level in direct response to the intensity of an environmental stimulus.1

Specifically, orthokinesis involves the speeding up or slowing down of an animal's rate of locomotion, or a change in the frequency with which it transitions from a state of rest to a state of movement. Because these movements are undirected, they do not necessarily lead the animal toward or away from a stimulus in a straight line, but rather alter how much the animal moves based on its surroundings.1

Examples of this behavior include:
* Lampreys: These animals exhibit increased activity in response to high light intensities.1
* Cockroaches: These insects show increased activity when exposed to low light intensities.1

Other invertebrates, such as flatworms and various fly larvae, also utilize orthokinesis as a fundamental behavioral mechanism.1