Slave-making ant (Chalepoxenus muellerianus)

Description

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Slave-making ant fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Slave-making ant description

Chalepoxenus muellerianus is a fascinating ‘slave-making ant’, so named because of its curious behaviour whereby it enslaves other species of ant to perform the work of the colony ⁽³⁾.

Chalepoxenus muellerianus is generally yellowish-brown and its body and legs are covered with fine erect hairs ⁽⁴⁾. Wrinkles can be found over its entire body, with the exception of the final segment, called the gaster, which is smooth and shiny ⁽⁵⁾.

Like all ants, Chalepoxenus muellerianus has a short, truncated waist segment, or petiole, which connects the middle body section to the final segment ⁽⁵⁾. Chalepoxenus muellerianus has a rounded petiole, and the postpetiole segment, found between the petiole and gaster, is virtually absent ⁽⁴⁾.

Size

Male body length: c. 2 mm ⁽²⁾

Female body length: c. 2.8 mm ⁽²⁾

Slave-making ant biology

All ants found within the genus Chalepoxenus are socially parasitic, raiding the nests of closely related Temnothorax species to capture their brood. The captured ants are raised as slaves of the Chalepoxenus ants to carry out the work of the colony ^{(3) (4)}. Work includes rearing the slave-maker brood, foraging for food and protecting the nest from other invading insects ⁽⁹⁾.

Chalepoxenus muellerianus predominantly parasitises Temnothorax unifasciatus, although it also parasitises approximately 12 other species of Temnothorax, including T. tuberum and T. recedens ^{(3) (4) (7)}. A colony will typically consist of a few dozen Chalepoxenus muellerianus individuals and from zero to several hundred host individuals ⁽¹⁰⁾.

Slave raids occur throughout the summer and involve several characteristic steps: scouting for host nests, recruitment of workers, fighting the host species and brood transport ⁽¹¹⁾. The queen Chalepoxenus muellerianus selects only the host brood, and has no use for the other host ants ⁽⁹⁾. Young female Chalepoxenus muellerianus are responsible for gaining access to the host brood, and capture, destroy or evict any host ants using their stingers ⁽⁴⁾.

Chalepoxenus muellerianus colonies generally tend to exclusively parasitise one species of host, due to imprinting upon the odour of the host species during a very sensitive period of growth. This significantly affects the queens choice of host during colony foundation, and workers almost exclusively raid the nests of host species already working in the slave-makers nest ^{(9) (10)}.

Slave-making ant range

Chalepoxenus muellerianus is one of the most common slave-making ants in Europe and is predominantly found in southern parts of the continent ⁽⁶⁾. It has a wide distribution in the Mediterranean region ⁽⁷⁾, ranging from Spain and southern France, to Italy, Croatia and as far east as Turkey ⁽⁴⁾.

Slave-making ant habitat

Colonies of Chalepoxenus muellerianus usually inhabit mountainous regions, and can be found in rock crevices, often in close proximity to woodland ⁽⁷⁾. Chalepoxenus muellerianus nests have been found in dry sticks in dense woodland, especially in areas containing black pine (Pinus nigra) ⁽⁸⁾.

Chalepoxenus muellerianus lives at a variety of altitudes ⁽⁴⁾, from 300 metres in the Vallée d’Ossau, up to 1,400 metres in San Juan de la Pena in the Pyrenees ⁽⁷⁾.

Slave-making ant status

Classified as Vulnerable (VU) on the IUCN Red List ⁽¹⁾.

Slave-making ant threats

The specific threats affecting Chalepoxenus muellerianus are unknown. However, in the Pyrenees, socially parasitic ants are threatened by the degradation of the natural habitat, due to forestry and agricultural practices, pesticide treatments and the snowsports industry ⁽⁷⁾.

Slave-making ant conservation

No conservation measures are currently known to be in place for Chalepoxenus muellerianus, but it occurs in several protected areas throughout its range, including the Serra da Estrela in Portugal ⁽⁴⁾ and the Abruzzi National Park in Italy ⁽¹²⁾.

Further investigation into the Chalepoxenus muellerianus population and behaviour is recommended to help determine exactly how this ant is threatened, and implement measures to protect it ⁽¹⁰⁾.

Find out more

More information on the conservation of ants and other insects:

• The Xerces Society:
  http://www.xerces.org/
• Buglife:
  http://www.buglife.org.uk/

Authentication

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:
arkive@wildscreen.org.uk

This species information was authored as part of the ARKive and Universities Scheme.

Glossary

Genus

A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.

Parasitic

Describes an organism that derives its food from, and lives in or on, another living organism at the host’s expense.

References

1. IUCN Red List (September, 2011)
   http://www.iuncredlist.org/
2. Finzi, B. (1924) Secondo contributo alla conoscenza della fauna mirmecologica della Venezia Giulia. Bollettino della Societa Entomologica Italiana, 56: 120-123.
3. Buschinger, A. (2009) Social parasitism among ants: A review (Hymenoptera: Formicidae). Myrmecological News, 12: 219-235.
4. Tinaut, A., Ruano, F. and Dolores Martinez, M. (2005) Biology, distribution and taxonomic status of the parasitic ants of the Iberian Peninsula (Hymenoptera: Formicidae, Myrmicinae). Sociobiology, 46: 449-489.
5. Buschinger, A. 1987 Synonymy of Leonomyrma Arnoldi 1968 with Chalepoxenus Menozzi 1922 (Hymenoptera: Formicidae). Psyche: 94: 117-126.
6. Buschinger, A., Ehrhardt, W., Fischer, K. and Ofer, J. (1988) The slave-making ant genus Chalepoxenus (Hymenoptera, Formicidae). Zoologische Jahrbücher, Abteilung für Systematik, 115: 383-401.
7. Buschinger, A. (1987) Teleutomyrmex schneideri Kutter 1950 and other parasitic ants found in the Pyrenees. Spixiana, 10: 81-83.
8. Heinze, J. (1987) Three species of social parasitic ants new to Turkey. Insects Sociaux, 34: 65-68.
9. Blatrix, R. and Sermage, C. (2005) Role of early experience in ant enslavement: a comparative analysis of a host and a non-host species. Frontiers in Zoology, 2: 13.
10. D’Ettorre, P. and Heinze, J. (2001) Sociobiology of slave-making ants. Acta Ethologica, 3: 67-82.
11. Schumann, R.D. (1992) Raiding behavior of the dulotic ant Chalepoxenus muellerianus (Finzi) in the field (Hymenoptera: Formicidae, Myrmicinae). Insectes Sociaux, 39: 325-333.
12. Mei, M. (1992) A survey of the socially parasitic ant genera Epimyrma Emery, 1915 and Chalepoxenus Menozzi, 1922 in Italy (Hymenoptera, Formicidae, Myricinae). Insectes Sociaux, 39: 145-156.