Caridoid Escape Reaction - Research With Crayfish

Research With Crayfish

Behavioral neurobiologists in the field of neuroethology have researched this behavior extensively for over fifty years in the crayfish species Procambarus clarkii. Based on studies of P. clarkii it was discovered that the tail- flip mechanism is characterized by a decisive, all-or-nothing quality that inhibits all unnecessary behaviors while generating a fixed action pattern for escape swimming. The type of escape response depends on the region of the crayfish that is stimulated but all forms require abdominal contractions. When a strong, unpleasant tactile stimulus is presented, such as a burst of water or the prod of a probe, a stereotyped behavior occurs in which the muscular tail and wide tail fan region of the telson are used like a paddle to propel the crustacean away from harm using a powerful abdominal flexions. The entire process occurs in a fraction of a second as movements are generated within two hundredths of a second (20 milliseconds) from the original trigger stimulus and the period of latency after a flexion is a hundredth of a second (10 milliseconds). Finally, the caridoid escape reflex requires that neurons be able to complete the arduous task of synchronizing the flexion of several abdominal segments. The speed, coordination, and decisiveness of the process seem to be the main attributes to its success.