SPONTANEOUS POLYDOMY IN LABORATORY COLONIES 
OF THE ANT LEPTOTHORAX CU RVISPINOSUS MAYR 
(HYMENOPTERA; FORMICIDAE) 
By Robin J. Stuart* 
Department of Zoology, Erindale College, 
University of Toronto, Mississauga, Ontario 
Canada L5L 1C6 
Introduction 
Leptothorax curvispinosus Mayr is a small, common ant in east- 
ern North America where it often nests in such preformed cavities as 
hollow acorns, hickory nuts, galls, stems and twigs. Its range and 
nesting preferences overlap broadly with those of two closely- 
related species, L. ambiguus and L. longispinosus (Creighton 1950; 
Alloway et al. 1982). Colonies within this group are both intra- and 
interspecifically aggressive; and although normally considered 
nonparasitic, they occasionally engage in facultative interspecific 
slavery, apparently by capturing and rearing brood from one anoth- 
er’s colonies. Facultative intraspecific slavery may occur more fre- 
quently (Alloway 1980). In addition, these species serve as hosts for 
the obligatory slave-makers Harpagoxenus americanus and L. dulo- 
ticus (Alloway 1979; for terminology see Stuart and Alloway 1983). 
All five species coexist in some areas, nest in close proximity to one 
another, and form dense local populations (Alloway et al. 1982; Del 
Rio Pesado and Alloway 1983). 
Approximately one third (36.3%) of individual L. curvispinosus 
nests (e.g. single acorns) are queenless, while about half (46.7%) are 
monogynous, and the remainder (17.0%) are polygynous (Headley 
1943; Talbot 1957; Alloway et al. 1982). Dissections have shown 
that polygyny in this species is more than just a superficial phenom- 
enon with over 90% of the queens in polygynous nests being 
inseminated and reproductive. Moreover, young queens often coex- 
ist with older queens, indicating that established colonies may 
♦Present address: Museum of Comparative Zoology Laboratories, Harvard Univer- 
sity, Cambridge, Mass. 02138. 
Manuscript received by the editor September 19, 1984 
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