Characteristics of Tramp Species
Luc Passera
Abstract
The attraction of tramp ants to unstable and perturbed environments linked to human activity explains their strong tendency to move. Less is known about other tramp species, but it seems they show the same tendency. For example, colonies of T. melanocephalum show no signs of aggression when mixed or when individuals are exchanged along foraging trails. Tramp species are characterized by true polygyny, i.e., nestmate queens show no signs of hostility toward one another that could be construed as dominance. A number of tramp ants, in which sexuals are normally winged, seem to have lost the capacity to undergo mating flights. A short queen life may seem disadvantageous, but it is compensated for by the large capacity of tramp species to produce and rear new queens. The following definition of tramp ants is proposed: tramp ants are ant species with small, sterile workers, widely distributed throughout the world by human commerce, living in close association with humans.