298 
Psyche 
[September 
In addition, the wing-flick may be a secondary alarm signal when 
it is not a comfort movement to rearrange the folding of the hind- 
wings. A startling display by both sexes of A. pseudonietana, , men- 
tioned briefly by Otte (1968) and observed by us in the western 
populations of that species, involves a sudden flicking open of the 
wings so that they point upward above the back with their outer 
surfaces mutually in contact. The wings sometimes stay open in this 
position for several seconds, with the brilliant red-orange disc of the 
hind-wings fully expanded. Grasshoppers which were approaching 
another individual will stop and back up or turn away when the 
latter performs this action. We have been able to cause the reaction 
with sudden probes or movements. We have noted also, as Otte has, 
that this action is effective against smaller insects, especially Diptera 
attempting to settle on the insect, and would be a good defence 
against tachinid and smaller asillid predators. However, in the six 
years in which we have studied the montane populations of A. con- 
spersa , this behavior has never been evidenced by more than a very 
rapid flick with a duration of a few milliseconds. Only with the 
comparative data of A. pseudonietana does the potential communica- 
tive value of the wing flick become evident. Probably this prolonged 
exposure of the brightly colored wings is attractive to vertebrate 
predators, and only the large species can afford to use this as a 
communicative signal. A conspersa, for example^ is so beset by avian 
predators in most areas that the life expectancy of whole populations 
is only three to four weeks (Willey & Willey, 1967). Our observa- 
tions (unpublished) on A. conspersa in the plains of eastern Colorado 
indicate that these larger individuals take much longer flights, and 
are more conspicuous in general behavior than the montane popula- 
tions. Much of the muted behavior of montane populations can be 
postulated as a result of extreme predator pressure. 
Aggression. 
The so-called “rival’s song” is a common term which perhaps 
gives faulty perspective to the function and makeup of the male- 
interaction songs. Suffice it to say that the flutter-rasp serves to turn 
off courtship advances by a male in, at least, two well-defined in- 
stances: 1) when the courted male is alone and 2) when the courted 
male is part of a pair in copulo. In this way, aggression is prevented, 
conspicuous courtship interplays and fighting are mitigated and the 
insects are less obvious to predators. Indeed, the male flutter-rasp 
could be considered as forming also a courtship interruption signal , 
since the receptive female is not adversely affected by the flutter-rasp 
of the male in copulo and remains in a quiescent state. 
