tropotaxis

Tropotaxis is a type of taxis, which is an unlearned behavioral response of an organism to a stimulus. In tropotaxis, an organism orients itself by comparing stimuli of different intensities acting on separate end organs. This means the animal uses simultaneous comparisons from two sides of its body to determine direction. For example, if one side is stimulated more than the other, the animal will turn towards the less stimulated side (negative tropotaxis) or away from the more stimulated side (positive tropotaxis). This behavior is common in many arthropods, especially insects, which have paired sensory receptors that allow for this comparison. Tropotaxis is a fundamental mechanism for animal orientation in response to environmental cues.123