QUEEN REPLACEMENT IN DEQUEENED COLONIES 
OF THE ARGENTINE ANT 
I RID OM YRMEX HUMILIS (MAYR) 
By Luc Passera, 1 Laurent Keller 2 and Jean-Pierre Suzzoni 1 
Introduction 
Replacement of killed or damaged queen by a new inseminated 
queen produced in the same nest is regularly accomplished in honey 
bees (Butler, 1967; Wilson, 1971; Michener, 1974). In the lower 
termites, e.g., Calotermes, it has been known for a long time that the 
removal of the sexual pair leads to the differentiation of neotenic 
reproductives from larval, pseudergate or nymphal forms (Grasse 
and Noirot, 1946; Nagin, 1972). In the higher termites, e.g., Nasuti- 
termes, dequeened societies may produce either neotenic reproduc- 
tives or differentiate young alates who have fully developed wings 
(Harms, 1927; Noirot, 1956, 1969; Thorne, 1982; Roisin and Pas- 
teels, 1986). 
In contrast, the replacement of queens by new inseminated queens 
produced in the same nest is very rare in ants. When colonies are 
orphaned, workers often start to lay eggs (see review in Passera, 
1984) but these eggs are not fertilized and therefore develop into 
males. Furthermore, after a colony has been dequeened, it often 
starts to rear queen larvae, then produces virgin queens (Passera, 
1984). But these virgin queens are not inseminated and thus may not 
replace the absent mated queens. Insemination generally occurs 
only during the nuptial flight. The probability that winged queens 
will return to their natal society after the nuptial flight is very low. 
The aim of this study was to determine whether queen replace- 
ment occurs in dequeened colonies of Iridomyrme x humilis. 
Material and Methods 
Large societies of the Argentine ant were collected in December 
1985 in Port-Leucate, near Perpignan, in Southern France. These 
'Laboratoire d’Entomologie, Universite Paul-Sabatier, 118 route de Narbonne, 
31062 Toulouse Cedex, France. 
2 Musee zoologique, Palais de Rumine, CP 448, Lausanne 17, Switzerland. 
* Manuscript received by the editor December 15, 1987. 
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