EMIGRATION RAIDS BY SLAVE-MAKING ANTS: A 
RAPID-TRANSIT SYSTEM FOR COLONY RELOCATION 
(HYMENOPTERA: FORMICIDAE) 
By Ellen C. Kwait' and Howard Topoff^ 
Introduction 
Polyergus lucidus Mayr is an obligate slave-making ant, found 
throughout north temperate regions of the world. Their slave raids 
are dramatic events in which columns of highly aroused workers 
penetrate nests of the related ant genus Formica, and carry the 
target colony’s pupae back to their own nest (Marlin 1969; Talbot 
1967). Although many of these pupae are consumed, varying 
numbers are reared through eclosion and become permanent mem- 
bers of the mixed-species nest. During the evolution of social para- 
sitism, Polyergus workers lost the ability to participate in the 
ordinary chores of foraging, nest maintenance, and brood rearing, 
all of which are left to the Formica slaves. 
Raiding behavior in Polyergus has only been reported in the con- 
text of slave raids, or of intraspecific territorial raids (Topoff et al. 
in preparation). Field observations of colonies in late summer, 
however, have revealed an entirely new function of raiding be- 
havior: the rapid transport of colony members during emigrations 
to new nests at the end of the slave-raiding season. During such 
colony movements, the low level of mixed-species ant traffic is 
periodically interrupted by the abrupt emergence of Polyergus 
workers, and their formation into a well-organized swarm. The 
Polyergus workers promptly “raid” the old nest, and transport 
adult Formica individuals to the new site. For such group processes, 
occurring in the context of nest relocation, we propose the term 
“emigration raid.” 
'Department of Biology, City College of CUNY, New York, N.Y. 10031. 
^Department of Psychology, Hunter College of CUNY, New York, N.Y. 10021, and 
The American Museum of Natural History, New York, N.Y. 10024 
Manuscript received by the editor May 28, 1983. 
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