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Psyche 
[Vol. 89 
complete account of polyethism in relation to the life history of A. 
pallipes is given by Traniello (1978). 
Predatory behavior. Prey were found in only three of the colonies 
collected. In two colonies larvae were found clustered around litho- 
biid centipedes (length = 1.5-2. Ocm), and in the third colony a 
carabid beetle larva was taken. In the laboratory, colonies were 
offered a variety of live arthropods that workers might encounter in 
leaf litter, soil, or rotting wood. Wood lice ( Oniscus ), house centi- 
pedes ( Scutigera ), and various millipedes were consistently rejected 
while small elatyrid, tenebrionid, and buprestid beetle larvae were 
carried to the nest and fed upon. The diet of A. pallipes appears to 
be restricted to live, linear-shaped arthropods that can be captured 
by workers. A related species, A. pluto, is entirely specialized on 
geophilomorph centipedes (Gotwald and Levieux, 1972). When 
large, robust-bodied centipedes ( Lithobius sp.) were offered to col- 
onies of A. pallipes, workers were unable to grasp the prey due to 
its escape movements and body diameter. It is difficult to imagine a 
condition under which large prey could be captured, even if they 
were “cornered” in a narrow gallery. When Lithobius of similar size 
were held with forceps, workers were still unable to subdue the centi- 
pede. Freshly killed centipedes were not accepted. It is therefore 
difficult to support the hypothesis of a nomadic life style for A. 
pallipes. Although this species of Amblyoponini does not appear to 
move its colonies to the location of large, previously captured prey, 
other species, such as Onychomyrmex do provide evidence linking 
group predation and nomadism in this primitive group of ants 
(Wilson, 1958). 
Prey capture and retrieval is very stereotyped, and solitary hun- 
tresses stalk prey in a highly methodical manner. As prey are 
approached, workers advance cautiously, apparently orienting to 
odors or air microcurrents produced by the prey. When within strik- 
ing range (2-3 mm) the mandibles are opened and the head is 
oriented orthogonal to the long axis of the prey. Then in a single 
motion the mandibles close around the prey, the legs elevate the 
body, and the gaster is swung forward. The prey is then repeatedly 
stung and the venom soon shows its paralytic effects. Initially, only 
the area adjacent to the cuticle penetrated by the sting is immobi- 
lized, and stinging continues until escape movements stop. Subse- 
quently, the retrieval of the prey begins after a brief period of self- 
