22 
Psyche 
[Vol. 89 
Although the raiding cerapachyine ants are usually enormously 
outnumbered by the worker force of the prey species, not one Cera- 
pachys worker was lost during all the raiding experiments in the 
laboratory. As can be seen from Fig. 2, Cerapachys and Sphinc- 
tomyrmex are excellently protected by a heavily sclerotized cuticle. 
The intersegmental joints, that is, the joints between head and 
thorax, and between thorax, petiole and gaster, are covered by 
cuticular projections so that no intersegmental membrane is ex- 
posed, even if the ant is twisted and bent to an extreme degree. 
In addition, Cerapachys and probably all the other cerapachyine 
ants have a most powerful sting that immobilizes the opponents 
within seconds. Not only the adults of the raided colony, but also 
the captured larvae and pupae are stung by the raiders before they 
are retrieved to the Cerapachys nest. Observations and experiments 
demonstrated that the prey larvae are kept in a stage of metabolic 
stasis and can thereby be stored for a period of more than two 
months. This food storage system enables Cerapachys to adjust the 
raiding activities to food requirement and supply. From the labor- 
atory experiments we can conclude that Cerapachys does not con- 
duct daily or periodic raiding expeditions. The frequency of raiding 
expeditions depends on the food supply stored inside the Cera- 
pachys nest. 
I was unable to demonstrate periodic nomadic behavior in Cera- 
pachys in the laboratory. I assume that nest emigrations might 
occur relatively frequently in this species, but that they do not fol- 
low a periodic pattern. Instead, environmental factors such as food 
supply or physical conditions of the nest site are likely to play the 
important role in inducing a Cerapachys colony to emigrate. 
Acknowledgements 
Many thanks to H. Engel-Siegel for technical assistance, to E. 
Seling for the SEM work, and to W. L. Brown and R. W. Taylor for 
identifying the ants. I am most grateful to R. W. Taylor and the 
Division of Entomology, CSIRO, Canberra (Australia) for their 
generous hospitality. This work was supported by a grant from the 
National Science Foundation BNS 80-021613, the National Geo- 
graphic Society and a fellowship from the John Simon Guggenheim 
Foundation. 
