page_title: Slave-making ant
section_title: Raids
hierarchical_section_title: Slave-making ant / Raids
caption_attribution_description: English: Polyergus lucidus returning from raid on Formica incerta. Two of the latter already incorporated into the mixed colony are visible to the right of the nest entrance.
context_page_description: Slave-making ants are brood parasites that capture broods of other ant species to increase the worker force of their colony. After emerging in the slave-maker nest, slave workers work as if they were in their own colony, while parasite workers only concentrate on replenishing the labor force from neighboring host nests, a process called slave raiding.
  The slave-making ants are specialized to parasitize a single species or a group of related species, and they are often close relatives to their hosts, which is typical for social parasites. The slave-makers may either be permanent social parasites or facultative slave-makers. The behavior is unusual among ants but has evolved several times independently.
context_section_description: Parasitized nests need to replenish the host workers periodically. This is achieved by raiding other nests in a process called slave raiding. The parasite workers are specialized for conducting raids in a two-step process. First, scouts individually search for potential host nests. When successful, the scout returns to its nest and recruits nest-mates to initiate the raid, during which slave-maker ants seize a brood and bring it back home. A colony may capture 14,000 pupae in a single season. Most slave-raiders capture only the young, but Strongylognathus sp. also enslave adult workers.
  In most parasite species, workers mark the way to its nest with pheromones and afterwards fellow slave-makers are attracted within a few seconds. They then go quickly to the targeted host nest, attack it, and carrying as many larvae and pupae as possible, return to their nest following the same trail marked by the pheromone. Rossomyrmex is the only reported slave-maker that exclusively uses adult transport and single recruitment chain instead of pheromones during raids, a behavior probably constrained by the arid habitat; raids take place in early summer when soil surface temperature can reach up to 30 °C (86 °F), a temperature in which pheromones would quickly evaporate.
  Workers of the attacked nest can fight or flee. In the host species Proformica, the most common behavior is flight, probably because hosts almost always lose fights. Most studies on the raiding behavior of species in the F. sanguinea complex confirm that slave raiders usually rout their opponents, who typically flee in a state of panicked alarm, and that aggressive encounters, when they occur, are brief and do not result in the death of adult individuals from either species. However, when large colonies of slave species offer resistance during raids prolonged fighting is possible and many workers of both species can be killed.
  Later, host workers emerging in the parasite nest will be imprinted on and integrated into the mixed colony where they will rear the parasite brood, feed and groom the parasite workers, defend the nest against aliens, and even participate in raids, including those against their original colony. Altruistic acts of slaves are thus directed toward unrelated individuals. One hypothesis suggests that slave deception is possible because slaves are captured as pupae and learn the slave-maker colony odor after emergence.
  However, in some cases, the enslaved ants rebel against their slave-maker ants, killing a large number of the slave-maker ant offspring. This is because "slaves can gain indirect fitness benefits by reducing parasite pressure on nearby host colonies, because these are often closely related to the slaves". Thus, the slave ants protect their native colonies from further raids by slave-maker ants.
caption: Polyergus lucidus returning from raid on Formica incerta. Two of the latter already incorporated into the mixed colony are visible to the right of the nest entrance.
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