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species of slave present, and thus the slaves must accept pupae from 
more than one species. It would be interesting to track the fate of 
captured pupae from different species, with the species composition 
of several generations of slaves that had eclosed in the slave-makers 
nest. 
Alloway (1982) speculated that the enhancement of pupae accept- 
tance in Leptothorax slaves by the presence of the slave-makers is 
pheromonally mediated, with a substance either applied to the 
pupae themselves or transmitted trophallactically by the slave- 
makers. Possibly, the “deterioration” of pupae acceptance, or the 
switch to conspecific pupae as a food source by F. schaufussi in the 
presence of the slave-makers, is mediated the same way. As the 
above comparisons suggest, the evolution of dulosis has apparently 
proceeded along quite different pathways in myrmicine and 
formicine ants. 
Summary 
Pupae acceptance behavior was studied in Formica species used 
as slaves by the slave-making ant genus Polyergus. Only one slave 
species is found in any single Polyergus nest. Pupae exchanges 
between different free-living colonies of F. schaufussi (enslaved by 
P. lucidus) and F. gnava (enslaved by P. breviceps ) demonstrated 
that workers treat pupae of alien conspecific colonies as their own. 
However, in the presence of their slave makers, enslaved F. schau- 
fussi workers consume a greater proportion of alien conspecific 
pupae than their free-living sisters. Also, enslaved F. schaufussi 
workers consume more pupae of a different slave species of P. luci- 
dus (F. nitidiventris) than of the resident slave species. Comparisons 
with studies of pupae acceptance in slave species of myrmicine slave 
makers suggest they may have followed a different evolutionary 
pathway to dulosis. 
Acknowledgments 
This study was supported by NSF Grant BNS-8402041, and by 
PSC-CUNY Grant 6-66346. We thank Stefan Cover for reading the 
manuscript. 
