In the ponerine ant, Pachycondyla villosa, 40 % of all collected founding colonies were pleometrotic associations with two (24 %) or three (16 %) queens. The egg-laying rate of solitary founding queens did not differ from that of queens in the two-queen groups, whereas individual queens in the three-queen groups laid significantly fewer eggs. Twenty-one weeks after collection pleometrotic associations contained significantly more workers than nests founded by haplometrosis. During the founding phase only one queen per founding association left the nest to forage. Within pleometrotic founding groups the number of eggs laid by individual queens did not differ, and no aggressive behavior occurred, even in the presence of workers. P. villosa seems to be one of the rare cases, where pleometrosis can lead to primary polygyny at least in the laboratory, with the queens coexisting in mature colonies without antagonistic behavior.

Queens of the neotropical ponerine ant Pachycondyla cf. 'inversa' may cooperate during colony founding. Pleometrosis leads to permanent primary polygyny, with queens still co-existing in the same nest when the colony has become mature. Using multilocus DNA-fingerprinting we examined the genetic structure of colonies. Nestmate queens are typically not close relatives. Excepting one pair of queens, which appeared to be closely related, the band-sharing coefficients of co-occurring queens were similar to the background similarity among individuals from different nests. In mature colonies, queens typically contribute equally to workers and sexuals. Only in one of seven colonies did one queen produce significantly more workers than the other. Polygynous ants with unrelated queens might provide an interesting system to test predictions from kin selection theory.

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The workerless parasitic ant,Leptothorax wilsoni, as yet known only from colonies ofLeptothoraxcf.canadensis, was found in five colonies of a second host species,Leptothoraxsp. A (sensu Heinze and Buschinger, 1989) near Escoumins, Québec. This is the first finding of an inquiline with more than one host species in the ant tribe Formicoxenni. In contrast to a previous statemem, the palp formula ofL. wilsoniis 4. 3.

Workers in queenless colonies of the ponerine ant Pachycondyla villosa establish linear or near-linear rank orders by antennation bouts and overt aggression. In these hierarchies, top-ranking individuals were reliably among the most productive egg-layers, but several lower ranking workers also laid considerable numbers of eggs. Though many of the subordinates' eggs were eaten by the-workers, we could show by multilocus DNA-fingerprinting that low-ranking individuals occasionally succeeded in producing adult males. However, the most dominant workers always had the highest reproductive success.