Hit distance and the predatory strike of the praying mantis

Summary

• 1. A series of preliminary experiments are conducted to determine the most convenient quantity of food mantids must receive in order to ensure a long life span and a high level of striking.

• 2. In other series of experiments the dynamic components of the strike are analysed. Preparatory movements tend to place the animal in an optimum position for striking and probably integrate a mechanism for estimating distances. Movements during the strike itself include the sudden displacement of the predatory legs and the lunge, i.e. a sudden thrust which takes place simultaneously with the movement of the predatory legs. An especial study of this latter component is presented. Computation previous to strike has to take this lunge into account in order to hit successfully.

• 3. The maximum motivation distance to strike lies between 70–80% of the foreleg length. Optimum hitting is achieved at a distance that represents 30–40% of foreleg extension. The gap between these two distances, i.e. 70–80% and 30–40%, is filled by the lunge. When the lunge is prevented by immobilizing the animal, a dramatic increase in the number of misses occurs.

• 4. There is a relationship between the maximum motivation distance to strike and optimum distance to hit, on the one hand, and the salient anatomical features of the grasping mechanism and the length of the forelegs, on the other hand.