As well as light other stimuli that invertebrates respond to include chemicals (chemotaxes), gravity (geotaxes) and water/humidity.

By moving more rapidly in areas of higher light intensity the animals will tend to stay in areas of lower light intensity longer.

Behaviour

Some of the behaviour shown by invertebrates can be classified as taxic responses and kineses. These forms of behaviour are innate not learned.

Taxic responses are directional responses to a stimulus.

Kinetic responses are non-directional responses to stimuli.