262 
Psyche 
[Vol. 95 
In conclusion, we may state that C. brunneus is a workerless spe- 
cies, derived from actively dulotic congeners. The queens have 
evolved the capability to coexist with adult host workers of the 
colonies, which they invade for colony foundation. The higher 
initial number of host workers makes slave-raiding less necessary. 
The C.b. queens have retained (always?) the feature of killing the 
host colony queens through stinging, as their dulotic congeners. 
Due to overgrazing and deforestation of the Great Atlas, as in 
other parts of Morocco, suitable habitats of C. brunneus have been 
largely destroyed. The population we studied is certainly but a tiny 
relic of a once much more widespread species, and it appears close 
to extinction. We do not know whether or not such relics exist 
elsewhere. It remains also questionable how much of the peculiar 
features of C. brunneus is due to the secondarily very small popula- 
tion size and isolation, and what was characteristic of the species as 
a whole. 
Summary 
Chalepoxenus brunneus, found in only one very small site in the 
Great Atlas of Morocco, represents a workerless parasitic species 
which is derived from actively dulotic congeners (“degenerate slave- 
maker”). The host species is Leptothorax cf. marocanus. The C.b. 
queen apparently eliminates the host colony queen by stinging her. 
She also stings to death a considerable part of the host colony 
workers, but, different from the dulotic congeners, the C.b. queen 
then is accepted by the remaining adult host workers. The sexual 
production is queen-biased (sex ratio 0.43 male/ female); mating 
presumably takes place close to the nest. We found no evidence for a 
female sexual pheromone, but the C.b. males react on the phero- 
mone from poison glands of other Chalepoxenus species. The life 
history of C.b. parallels that of other “degenerate slave-makers” in 
the genus Epimyrma. 
Acknowledgments 
We are greatly indebted to the Deutsche Forschungsgemeinschaft 
for a grant to A. Buschinger and J. Heinze, which enabled us to 
collect in Morocco; and to Conseil Scientifique de lTJniversite P. 
Sabatier, Toulouse, for financial support for the “Study of Moroc- 
can Ants” by H. Cagniant and X. Espadaler. 
