Monomorium santschii is a species of ant that is native to Tunisia. The most famous species in the Monomorium genus is the highly invasive pharaoh ant, Monomorium pharaonis. It is a parasitic ant that has no worker caste. The queen enters the colony of a different species and, probably by employing a pheromone, she forces the host workers to kill their queen. She then uses these workers as slaves to bring up her own offspring.