1981] 
Steiner — Anti-predator Strategies 
7 
Fig. 3: Postural defense replacing escape (startle and/or death feigning display?). 
The attacked grasshopper froze into a hunched posture, with appendages tucked in, 
thus protecting the vulnerable ventral surface. The colorful wings, showing striking 
semi-circular dark markings, are fully extended and/or flutter convulsively. The 
wasp, after many vain efforts, managed to slip under the grasshopper (one leg is still 
visible on the right of the grasshopper head) and will attempt to reach the vulnerable 
ventral surface of the thorax made less accessible by the posture and interposition of 
appendages (obstruction behavior). 
Uncommon and odd postural defenses replacing escape: 
stationary wing flashing or extension; body arching; freezing 
(Fig. 3) = first line of defense. 
a) Field observations 
These rare occurrences guarantee that such responses are not 
reducible to captivity artifacts. 
The first observation was made on Sept. 4, 1972, near the end of 
the morning, in the Arizona grassland desert. One hunting Prionux 
(parkeri?) suddenly pounced on a motionless grasshopper. Instead 
of trying to escape, as usual, the latter was seen with the colorful 
wings open, fluttering convulsively, with a startling suddenness, 
thus producing a striking color flash. The hind legs were rigidly 
extended behind like in the flying posture (Fig. 5b). However the 
