[The behavioral reactions of fresh-water crayfish to sensory exposures: the autonomic components].

Sudden changes of the environment such as a short-lasting shadowing of an animal, placing of some small objects into the tank, light vibrations of the bottom etc. Caused vegetative responses in the freely moving native crayfish Astacus astacus and the American crayfish Procambarus cubensis adapted for many generations to aquarium habitat. We observed mainly a sudden decrease of ECG-frequency correlated with similar changes in the electrical activity of the muscles moving the specific ventilatory appendages, scaphognathites (scaphognathite-gram, SGG). Rise of the ECG and SGG rate was shown during and after the illumination of dark-adapted animals. The rate changes could be coincided with different changes of the amplitude of both ECG- and SGG-waves. It should be noticed that these vegetative responses took place mostly without any body movements of the animal. We suggest that the crayfish responses to sudden environmental changes are similar to mammalian orienting response; probably they also include an emotional component.