Turning behaviour related to optical stimuli in Tenebrio molitor

The walking behaviour of the beetle Tenebrio molitor was studied on a compensating running globe under optical stimuli. The animals show a clear frequency distribution for the duration of continuous walking between abrupt stops. The turning behaviour after a light is switched on or off is correlated with these frequency distributions. The circadian rhythmic changes of activity and of the sensitivity of the eyes influence the turning behaviour. A model describes the phenomenon of ‘sensory storage’ as the result of an integration over the reaction probabilities given by the frequency distributions.