Slave-making ant (Harpagoxenus canadensis)

GenusHarpogoxenus (1)
SizeWorker length: c. 3 mm (2)
Queen length: c. 4 mm (2)

Harpagoxenus canadensis is classified as Vulnerable (VU) on the IUCN Red List (1).

Like other species in the Harpagoxenus genus, Harpagoxenus canadensis is known for its ‘slave-making’ behaviour, enslaving ants of other species to provide workers for its own colony. This small ant is brown in colour and the workers, the wingless females, have club-like tips to their antennae. In contrast, males of this species have filliform (whip-like) antennae (2).

Harpagoxenus canadensisis larger than its host species, Leptothorax muscorum, which may be advantageous in its parasitic lifestyle (3).

As its name suggests, Harpagoxenus canadensis is found mainly in eastern Canada, although there are also records from the northern United States (4) (5).

Harpagoxenus canadensis is most commonly found in rotten wood, although, like other species in the Harpagoxenus genus, it can also be found in bogs, marshlands and under tree bark (3).

The ‘slave-making’ process begins with Harpagoxenus canadensis scouting the area around its nest for colonies of its host species, Leptothorax muscorum. Once the scouting ants have discovered a host’s nest, they lead other ants to the nest using a chemical secretion which the other ants can follow (3).

Harpagoxenus canadensis will then invade the host’s nest, engaging in fights with the host species which may last for long periods of time, usually between two and three hours. Harpagoxenus canadensis workers will use their mandibles to pull the limbs and antennae off their opponents. It is currently not clear whether Harpagoxenus canadensis also use chemical secretions to cause the defending workers to attack each other (3).

Following the invasion of the nest by Harpagoxenus canadensis, a group of the host species Leptothorax muscorum will generally flee with part of the brood in order to try and preserve the colony. The Leptothorax muscorum workers remaining in the nest are killed by the invading Harpagoxenus canadensis (3).

Once the host nest has been overtaken, Harpagoxenus canadensis workers carry the captured Leptothorax muscorum brood back to their own nest, or move their colony to the raided host nest, where the pupae are raised as part of the colony and become workers tasked with foraging and caring for the Harpagoxenus canadensis brood (3).

The Harpagoxenus canadensis nest is thought to be monogynous, meaning that there is only one queen (5).

Although Harpagoxenus canadensis is currently considered threatened by the IUCN Red List (1), it is not yet clear what specific threats this ant faces.

There are currently no specific conservation measures in place for Harpagoxenus canadensis.

To find out more about the conservation of ants and other insects:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (March, 2011)
  2. AntWeb - Harpagoxenus canadensis (March, 2011)
  3. Stuart, R.J. and Alloway, T.M. (1983) The slave-making ant, Harpagoxenus canadensis M. R. Smith, and its host-species. Behaviour, 86(1): 58-90.
  4. Global Ants - Harpagoxenus canadensis (March, 2011)
  5. Buschinger, A. and Alloway, T.M. (2007) Caste polymorphism in Harpagoxenus canadensis M. R. Smith (Hym. Formicidae). Insectes Sociaux, 25(4): 339-350.