Cooperation Between Dealate Queens During Colony Foundation in the Green Tree Ant, Oecophylla Smaragdina

Colony reproduction in ants typically occurs through the foundation of a new nest by a single mated queen (haplometrosis), but sometimes involves several cooperating queens (pleometrosis). Pleometrosis enables successful colony foundation under adverse conditions (reviewed by Rissing and Pollock 1988), but it is not necessarily followed by polygyny once the colony has become established. There exist two species of Oecophylla, both of which are conspicuous arboreal ants who weave living leaves into nests using larval silk. Although mature colonies can be extremely populous (half a million workers) and can be made up of hundreds of nests in many adjoining trees (H611dobler and Wilson 1977, H611dobler 1983), they are strictly monogynous (e.g. H611dobler and Wilson 1983a, Greenslade 1971). Early observations on colony reproduction in the Asio-Australian species O. smaragdina by Dodd (1902) and Maxwell-Lefroy and Howlett (1909:233) have led to the assumption that a new colony is established by a single queen. However, various observations on the African species O. longinoda suggest that it is pleometrotic. Richards (1969) observed a group of dealate queens together with many eggs and larvae on a window ledge, and Ledoux (1950) failed to collect single foundresses with brood. Here we document for the first time pleometrosis in O. smaragdina, and this behavior is discussed in the context of the monogynous state of established colonies.