1981] 
Steiner — Anti-predator Strategies 
17 
Some Prionyx wasps experienced great difficulties in squeezing 
themselves under such grasshoppers (Fig. 3, one leg of the wasp 
visible). Sometimes also the wasps succeeded in turning over such 
grasshoppers, venter up (Fig. 4). Even so, stinging was difficult. 
Reduced accessibility might be an accidental by-product of the 
“disablement” display or a more direct result of wasp-grasshopper 
coevolution. The apparent immunity of Acrotylus grasshopper 
nymphs to Tachysphex peetinipes was also attributed to restricted 
accessibility linked with dense and long pilosity (Ferton 1910, p. 
158). Body arching has also been observed on some other orthop- 
terans and is sometimes associated with the release or violent 
expulsion of repellent fluid, as in Poekilocerus buforus (Fishelson 
1960). 
d) “Intimidating” and aggressive defensive elements (Fig. 5d). 
If the posture shown in Figs. 3 and 5d is also an eyespot display 
then it has an intimidating as well as “bluff’ value. 
Sideways rocking, known from some mantids (Crane 1952) and 
also forward-backward rocking were often observed in crickets, just 
before or after contact with Liris wasps (Steiner 1968), suggesting an 
intimidating function. This was also observed in Empusa egena in 
response to attacks by the sphecid wasp Stizus distinguendus Handl. 
(Deleurance 1941, pp. 287-288), along with other aggressive re- 
sponses such as wings open, striking with the raptorial fore legs. 
Rocking was also observed in some phasmids (Crane 1952) and 
roaches such as Periplaneta fuliginosa (Simon and Barth 1977, p. 
307). Crickets also sometimes froze into odd or intimidating erect 
postures difficult to interpret as “death feigning” (Steiner 1962, 
1968). Absence of stinging in such cases, if related at all to the 
display, might depend on: (1) the oddity of the posture, as Chauvin 
and Chauvin (1977) suggest (the vertical posture is in sharp contrast 
with the usual horizontal one), or (2) the possible intimidating 
effects associated with increased height (bluff behavior), (3) preda- 
tor mimicry, namely a mantis-like appearance (see Steiner 1968, 
Fig. i, p. 267). [Remark: this latter possibility was considered far- 
fetched by one reviewer of the paper cited and consequently 
eliminated from the text. . .and yet Simon and Barth (1977, p. 307, 
Fig. 2) describe a somewhat comparable rare posture from the roach 
Periplaneta fuliginosa which they interpreted (probably rightly) as a 
“Mantis-threat”!] 
