Protomognathus americanus queens (winged females) and males mate in July, following which the female sheds her wings and crawls about on the ground in search of a nearby nest belonging to one of three species of ant: Leptothorax ambiguus, Leptothorax curvispinosus or Leptothorax longispinosus. Once a nest has been located, the queen proceeds to invade the nest, savagely ridding it of Leptothorax ants by seizing each worker ant by its antennae, dragging the ant outside the nest, and flinging it to one side. The queen moves rapidly, to avoid attacks from the Leptothorax workers (3).
After the queen has ransacked the colony in this manner for a while, the remaining Leptothorax workers and queen panic and desert the nest, leaving behind their larvae and pupae. As these Leptothorax young develop, they recognise the female Protomognathus americanus ant as their queen and serve her accordingly, carrying out the necessary foraging, nest-building and caring for the new queen’s own brood (3).
When the new Protomognathus americanus queen’s own brood develop they are not like traditional worker ants, as the Leptothorax slaves adopt this role. Instead, they remain in the nest while the slaves feed them by regurgitating food into their mouths and periodically go in search of a new Leptothorax nest to raid, in order to bring back Leptothorax larvae and pupae to replenish the slave work force. If asingle Protomognathus americanus ant locates a Leptothorax nest it may attempt to overtake it, but if unsuccessful, the ant will return to the home nest and lay a chemical trail to entice a larger group of ants towards the Leptothorax nest (3).