PSYCHE 
Vol. 80 
September, 1973 
No. 3 
THE EVOLUTION OF CRYPTIC POSTURES IN 
INSECTS, WITH SPECIAL REFERENCE TO SOME 
NEW GUINEA TETTIGONIIDS (ORTHOPTERA)* 
By Michael H. Robinson 
Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa 
Panama Canal Zone 
Introduction 
A number of authors (see, for instance, Cott 1940, and de Ruiter 
1952) have suggested that the structural adaptations to defense by 
concealment that are found in insects can only function efficiently 
if they are accompanied by appropriate behavior patterns. These 
behavior patterns include diurnal immobility and the adoption of 
complex resting positions. A resting position may involve both the 
selection of an appropriate location (background selection) and the 
assumption of a special resting posture. The latter may entail sys- 
tems that function to suppress signals that predators could use to 
locate the insect, and in addition may give rise to signals that convey 
false information about the edibility of the insect. The first category 
involves the strategy of concealment, the second category involves 
the strategy of mimicry. 
I have suggested (Robinson 1968, 1969a, 1969b, 1973) that the 
protraction of the anterior legs of stick-mimicking insects (particu- 
larly phasmids and mantids, but including insects of other orders) 
in line with the long axis of the body has, at the very least , a dual 
function with respect to the signals that are potentially detectable by 
the predator. Thus, this behavior may : 
(a). Conceal the legs, head and antennae of the insect, thereby 
suppressing signals that could be used as prey-detection cues by a 
predator. 
* Manuscript received, hy the editor June 6, 1973. 
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