Light back reflex
The light back reflex or the light compass orientation is a reflex for setting a certain body position in space, which occurs above all in aquatic animals. The back is always turned towards the incident light. The decisive parameters for the light back reflex are the direction of incidence of the light and the light intensity ; the eyes in particular act as perceiving sensory organs .
Due to the light back reflex and different types of balance organs , aquatic animals such as fish , amphibians and insects can assume an optimal swimming position, with the belly side facing the bottom and the back side facing the water surface.
A number of experiments on the light back reflex were carried out with fish in particular . Light-sensitive fish, for example, assume an inclined position of around 50 ° when light falls from the side when swimming. If the organs of equilibrium reacting to the direction of gravity are removed, the back is completely aligned with the light source and the fish swim on their side or on their back. The extent of the light back reflex can be influenced by various stress factors , disturbances can provide conclusions about illnesses or environmental disturbance factors.
literature
- Keyword “light back reflex” in: Herder-Lexicon of Biology. Spectrum Akademischer Verlag GmbH, Heidelberg 2003. ISBN 3-8274-0354-5