1981] 
Steiner — Anti-predator Strategies 
13 
mouth-based defenses (biting, regurgitating), now discussed, since 
they effectively neutralize hind leg defenses with their powerful 
“embracing” legs. Correspondingly, these wasps deliver the first 
sting in the throat, not around the hind legs (Steiner 1976). 
Biting and retaliation ( aggressive defense: 
Edmunds 1974, p. 182) 
Orthopterans commonly use their powerful jaws for threat, 
intimidation or even active defense, retaliation, if not for predation. 
The predaceous North American katydid Neobarettia severely bites 
and displays the open mandibles as part of the threat-intimidation 
display (Cohn, in Sebeok 1977, p. 342, Fig. 5b). 
In one observation in captivity (Arizona, June 24 1973, 1335 h) a 
wrongly positioned Tacky sphex tarsatus (No + 1042) was clearly 
and severely bitten by a nymph Trimerotropis pal/idipennis p. 
(Burm.) (No + 1098) during a stinging attempt. This suggests that 
the wasp is particularly vulnerable before proper positioning is 
achieved and that strong selection pressures in the direction of 
minimum risk must have shaped the usual stinging postures. The 
penalty for wrong posturing can be very heavy. Thus the above 
wasp was found dying in the cage the next day, June 25, most likely 
as a result of this violent retaliation of the prey. 
Importance of mouth-based defenses is confirmed by the fact that 
many orthoptera-hunters deliver a special throat sting (Steiner 1962, 
1976) sometimes even before any other sting (e.g. Prionyx parkeri). 
This also eliminates opposition to prey-transport and storage in the 
nest (and furthermore “de-activates” the prey that recovers in part 
from paralysis, later: Steiner 1963a). In sharp contrast, Oxybelus 
uniglumis wasps omit the throat sting when they paralyze their non- 
recovering fly-prey devoid of subesophageal ganglion and of poten- 
tially dangerous mouth parts (Steiner 1978, 1979). Orthoptera- 
hunting wasps with missing legparts or damaged antennae are often 
found, particularly late in the season. This might be a testimony to 
the efficiency of bites of their prey but also result from intra-specific 
fighting (see for instance Brockmann and Dawkins 1979, for Sphex 
ichneumoneus ) and/or accidents during nesting. A female Pal- 
modes carbo with two deep dents on the back of her abdomen was 
found in southern British Columbia. It is probable that this 
represented severe bites received from one of their large, often 
