1981] 
Steiner — Anti-predator Strategies 
5 
Fig. 2: Regurgitation of a repelling fluid. An acridid grasshopper (Oedipodinae), 
just paralyzed by a Prionyx parkeri wasp, lies on its back and a huge drop of fluid 
covers a large surface of the ventral thoracic area where all four stinging sites are 
located (indicated by white dots and arrows). Wasps often hesitate to dip their 
abdomen tip into this viscous, probably offensive, fluid. Accidental contact triggers 
vigorous body rubbing in an attempt to eliminate the unpleasant fluid from the body 
surface. 
and long-range escape were impossible, however, because of space 
limitations. 
There was no evidence of active avoidance of Prionyx or Tachy- 
sphex wasps by grasshoppers (“predator recognition”), even after 
repeated attacks. Escape was always in direct response to attack, 
imminent attack, or at least sudden movements such as a wasp 
running and/or pouncing. Thus predator and prey were often seen 
basking together. Immediately following an attack, the escape 
threshold was clearly lowered, however. 
Mechanical defenses after contact: kicking, pushing and/or 
brushing away the wasp: biting; wing fluttering and flying 
= second line of defense (Fig. 1) 
After contact, Prionyx wasps attempt to anchor themselves to the 
struggling or escaping grasshopper. They try to gain a firm grip 
