PUPA ACCEPTANCE BY SLAVES OF THE 
SOCIAL-PARASITIC ANT POLYERG US* 
(HYMENOPTERA: FORMICIDAE) 
By Linda Pike Goodloe and Howard Topoff 
Department of Psychology, Hunter College of CUNY 
New York, N.Y. 10021 and 
Department of Entomology, The American Museum 
of Natural History, New York, N.Y. 10024 
Introduction 
Slave-making ants of the formicine genus Polygerus are obliga- 
tory parasites of the genus Formica. To maintain a supply of slaves, 
Polygerus workers raid Formica colonies and capture brood, pri- 
marily pupae. Some of this brood survives to eclosion in raiders’ 
nest, and these new workers perform their species-typical behaviors 
in the service of the slave-makers. Colonies of the eastern species P. 
lucidus, and of the western species, P. breviceps, contains only one 
species of slave, unlike related faculative slave-makers of the genus 
Formica. P. lucidus enslaves the subgenus Neoformica, while P. 
breviceps uses the Formica fusca species group (Creighton, 1950). 
Formica slaves within a Polygerus nest rear through eclosion 
both the Polygerus brood and the brood retrieved from various 
Formica nests. An encounter between two Formica workers from 
different nests, either free-living or enslaved, is fiercely aggressive. 
Under laboratory conditions where mutual avoidance is impossible, 
injury or death usually result (Goodloe & Topoff, unpublished 
data). Formica workers may be able to perceive colony specific 
differences in pupae (Wilson, 1971). If slaves were inclined to ignore 
or destroy pupae from alien conspecific colonies, survival of cap- 
tured brood would be threatened. For the myrmicine slave-maker 
Harpagoxenus americanus, Alloway (1982) has shown that the 
presence of the slave-makers enhances the pupae-acceptance behav- 
ior of the slaves (fewer pupae are eaten and therefore more are saved 
to eclose). 
* Manuscript received by the editor May 30, 1987. 
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