POLYDOMY IN THE SLAVE-MAKING ANT, 
HARPAGOXENVS AMERICANVS (EMERY) 
(HYMENOPTERA: EORMICIDAE)* 
Bv 
Maria Gi adaluph Del Rio Pesado and Thomas M. Alloway 
Erindale College 
University of Toronto 
Mississauga, Ontario L5L 1C6 
Canada 
Introduction 
Slavery in ants is a form of social parasitism in which parasitic 
“slave-making” species exploit the labor of workers derived from 
host-species colonies. The slave makers raid host-species nests, 
where they capture all or part of the brood. Subsequently, workers 
maturing from the captured brood form a social attachment to the 
slave makers and perform all the usual worker-ant functions in the 
parasites’ colony (see review in Buschinger et al. 1980). 
Harpagoxenus aniericanus (Emery) is an obligatory slave maker 
living in eastern North America, where it forms mixed colonies with 
members of certain Leptothorax species (see Alloway 1979). Two 
kinds of H. aniericanus nests are found: “primary nests” containing 
a single slave-maker queen and slaves with or without slave-maker 
workers, and “secondary nests” consisting of slave-maker workers 
and slaves without a slave-maker queen (Creighton 1927; Sturtevant 
1927; Buschinger & Alloway 1977). Primary nests are apparently 
established when a parasite queen successfully invades a host- 
species nest (Wesson 1939), but the origin of secondary nests is 
questionable. The problem is compounded by the fact that secon- 
dary nests are usually more numerous than primary nests and fre- 
quently produce slave-maker females (workers and / or queens) from 
'This research was supported by a scholarship from CONACYT [Consejo Nacional 
de Ciencia y Tecnologia, Mexico] to the first author and by a grant from the Natural 
Sciences and Engineering Research Council (Canada) to the second author. The 
authors would like to thank Victor Chudin for his assistance in collecting the data 
and Robin Stuart for his constructive comments on the manuscript. 
Manuscript received hy the editor February 19, 1983. 
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