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[Vol. 95 
queens ensures the colony’s continuation in the event of one or more 
queen deaths. In many monogynous species the death of the queen 
results in the dissolution of the colony (e.g., Oecophylla spec., Van- 
derplank, 1960). Polygyny, however, is not the only mechanism for 
queen replacement observed in ants. In some species, several dealate 
females may be present in a colony but only one lays eggs. Occa- 
sionally some of the extra females are sterile, uninseminated females 
that somehow missed the mating flight. Others are inseminated 
females, which do not lay eggs in the presence of the fully fertile 
queen. Tschinkel and Howard (1978) demonstrated the presence of 
these sterile, inseminated females in colonies of Solenopsis invicta by 
removing the single fertile queen. In 27 percent of the test colonies a 
previously sterile female began to lay fertilized eggs. 
The presence of sterile, though inseminated females, in addition 
to a fertile queen has been termed “functional monogyny.” Origi- 
nally described by Pardi with the paper wasp, Polistes gallicus 
(1940; 1946), functional monogyny appears to be very rare in ants. 
In addition to Solenopsis invicta, in which it occurs along with 
polygyny and monogyny, functional monogyny has so far been 
proven to exist only in some species of the well-studied ant tribe 
Leptothoracini: in Leptothorax gredleri (Buschinger, 1968a), Lepto- 
thorax sphagnicolus (Francoeur, 1986), and in some, if not all spe- 
cies of the xenobiotic genus Formicoxenus (Buschinger, 1979a; 
Buschinger and Winter, 1976; Buschinger et al., 1980; Francoeur et 
al., 1985). 
With the exception of L. gredleri, which is fairly common in some 
populations in Bavaria (Buschinger, 1966), functionally monogy- 
nous leptothoracines are quite rare. Thus, more detailed studies on 
colony and population structure are difficult. During the past few 
years, however, we have collected numerous colonies of a new, func- 
tionally monogynous species of Leptothorax closely related to the 
palaearctic species L. muscorum. The taxon is to be described by A. 
Francoeur (Univ. of Quebec, Chicoutimi); here we again refer to it 
as Leptothorax spec. A (Heinze and Buschinger, 1987). This ant is 
common in suitable habitats throughout Quebec and the northern 
part of New England, and it is abundant especially on the rocky 
shore of St. Lawrence River near Tadoussac, Quebec. A most 
important trait of Leptothorax spec. A is that it has a genetically 
mediated queen-polymorphism, with primarily winged, gynomor- 
