1983] Blondehim & Frankenberg — Sounds of Grasshopper 391 
apparent from the present results that the appetite for grasshoppers 
may be tempered by their behavior. In the present case, mandibu- 
lar sounds emitted by P. syriaca appeared to interfere with preda- 
tion by this gecko. 
Because of its confinement in the cage of the gecko during exper- 
iments, a grasshopper which had chirped its way to freedom was 
prevented from escaping its predator as it might in the wild. P. 
syriaca, though it cannot fly, is an excellent jumper and under nat- 
ural field conditions would probably have jumped far and hidden 
itself well before the predator had recovered from its encounter. 
The sound itself has a wide frequency spectrum such as that 
characterizing alarm calls of birds (Marler 1957; Morton 1977). The 
utility of sounds such as these might include conspecific warning, 
since these grasshoppers occur in loose aggregates. However, hold- 
ing a chirping male in close proximity to conspecifics, or playing the 
recorded sound back into a cage of P. syriaca failed to produce any 
discernible reaction. 
It was observed that these grasshoppers are often seized headfirst. 
It is suggested that the hollow bones of birds, or the large buccal 
cavity of lizards may act as a resonating chamber, enhancing the 
intensity of the insect’s sounds or vibrations. 
For the few grasshopper species known to produce^mandibular 
sounds spontaneously or in encounters with conspecifics, an intra- 
specific communicative function has been suggested: {Paratylotropi- 
dia hrunneri, Alexander 1960; Oedaleonotus fuscipes, Varley 1939; 
Calliptanius italicus, Faber 1949) but no experiments have been 
reported in support of this hypothesis. Henry (1942) reports that 
Mesamhria duhia emits a shrill creak when seized and investigation 
may reveal that this sound, like the protest sound of P. syriaca 
studied here, may play a predator-deterrent role. 
Whether a remnant of an intraspecific communicative cue or a 
language of predator deterrence, a signal such as that presented here 
has quite probably been playing a part in the evolutionary history of 
the struggle for survival in this species. 
Acknowledgment: 
This paper is intended to answer the question of Dr. David 
Blondheim, who at age 10 asked his mother (SAB) why P. syriaca 
made those strange noises with its mouth when you caught it. 
Thanks are extended to Dr. N. Ben-Eliahu and to Profs. R. Galun, 
