16 
Psyche 
[Vol. 88 
pronuba (in Edmunds 1974) and also many orthopterans. For the 
latter, wing opening (lifting) is for instance part of the dramatic 
threat-intimidation display of Neobarettia already mentioned (in 
Sebeok 1977, p. 342) or the one of Phymateus. Since these latter 
species are potentially dangerous and/or distasteful such displays 
are usually interpreted as warning (in Edmunds 1974, pp. 148, 154; 
see also for instance Frazer and Rothschild 1962). The first species 
bites severely while the latter has strong hind leg spines and secretes 
a repelling fluid if further molested. When exhibited by harmless 
species such as the stick insect Metriotes diocles (e.g. Bedford and 
Chinnick 1966; Robinson 1968a) or common grasshoppers it is 
considered as mere “bluff’ based on a startle effect and/or an 
apparent increase in size, height, volume, etc. (intimidation beha- 
vior). Similar actions are reported from some cicadas and mantids 
and are particularly dramatic in the African mantid Idolium 
diabolicum (in Wickler 1968). 
b) Display of dark markings or “eyespots” 
Eyespots are commonly displayed by moths (see for instance Blest 
1957, 1964). If even very imperfect imitations are considered 
effective then perhaps this also applies to the semi-circular dark 
markings displayed by grasshoppers (Figs. 3 and 5d). Rarity of the 
display is essential (in Edmunds 1974, p. 168). 
c) Appearance of disabled, dying or dead insect (thanatosis) with 
freezing, hunching and appendages tucked in (Fig. 5d). 
Inhibition of movement in itself or freezing is likely to lower the 
probability of detection and / or attack by predators that hunt 
moving live prey visually (e.g., Steiner 1962, 1976 for cricket- 
hunting Liris wasps). This probably includes many digger wasps. 
Thanatosis is known from a number of insects, also orthopterans 
(Edmunds 1974, p. 172; Robinson 1968a). The prey might also be 
considered unsuitable because of the unusual appearance as such 
(oddity effects). The latter is illustrated by “protean defenses” an 
unpredictable, erratic and highly diverse behavior (in Edmunds 
1974, pp. 144-145; see also Chance and Russel 1959; Humphries 
and Driver 1971, etc.). 
Furthermore, grasshoppers with wings spread, appendages 
tucked in and body strongly arched (Fig. 3) also seem less exposed 
because of reduced access to the vulnerable stinging sites, all located 
on the well protected ventral surface of the thorax (Steiner 1981). 
