RELATION BETWEEN PREY AND PREDATOR — ROEDER 299 



those obtained for insects, bearing out the possibility that startle 

 response times in animals which are likely to interact or compete tend 

 to reach the same minimum values. 



THE PREDATOR 



From the foregoing it is concluded that in the startle response of 

 the prey quality of information is subordinated to speed of operation 

 and simplicity of neuronal connections. The information require- 

 ments of a predator are much more complex, and will certainly be 

 more difficult to analyze in terms of the essential neural events. 



In the case of a predator whose prey are active and able to escape, 

 feeding behavior may be divided roughly into two stages. During the 

 first stage, the stalk, detection, identification, and orientation to the 

 prey require the reception and integration of a considerable amount 

 and variety of information, and speed at this stage may be neither 

 possible nor essential. The second stage, the attack, depends upon 

 speed in those predators whose prey is active, and may be steered en- 

 tirely by information gathered during the first stage. 



An excellent example of this type of behavior is seen in the capture 

 of other insects by the praying mantis. The factors directing the 

 strike of the forelegs in Parastagmatoptcra unipunctata and other 

 Mantidae have been analyzed in some detail by Mittelstaedt (1954, 

 1957). The final stage in the attack, extension of the prothoracic 

 legs followed by flexion of the spined tibia on the femur so as to 

 grasp the prey, appears to be so rapid as to be unsteerable during its 

 execution, and is analogous to throwing a ball or firing a gun. Ac- 

 cording to Mittelstaedt extension of the forelegs is accomplished in 

 1 1 to 30 msec. 



The full strike up to the instant of contact with the prey takes 

 somewhat longer. This was determined by attaching a balsa wood sup- 

 port to the prothorax of an adult mantis. The support was inserted 

 in a phonograph pickup so that sudden forward acceleration of the 

 prothoracic legs at the beginning of extension produced a ballistic 

 recoil in the mantis and support and a pulse of current in the pickup. 

 The feet of the mantis rested on a light paper platform suspended 

 from a thread and counterbalanced with a weight roughly equivalent 

 to that of the mantis. This method of mounting permits practically 

 normal behavior and prey capture (Mittelstaedt, 1954, 1957)- A live 

 fly was attached by wax to a small rod in another pickup and moved 

 within striking distance of the mantis. 



When the mantis struck at the fly the recoil of its body triggered 



