Crematogaster nigriceps

Crematogaster nigriceps
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Crematogastrini
Genus:	Crematogaster
Species:	C. nigriceps
Binomial name
Crematogaster nigriceps Emery, 1897 Specimen Labels
Subspecies
Crematogaster nigriceps prelli Forel, 1911 Crematogaster nigriceps saganensis Consani, 1952

One of four ant species (also Crematogaster mimosae, Crematogaster sjostedti, Tetraponera penzigi) that live on Vachellia drepanolobium. This small arboreal ant assemblage, nesting in this dominant Africa savanna tree, have been the subject of intensive research by a large group of ecologists studying species interactions and species co-existence.

At a Glance

• Ant-plant specialist

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 32.583333° to 3.916666667°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Afrotropical Region: Kenya, Somalia (type locality).
Palaearctic Region: Israel.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Vachellia drepanolobium  Vachellia drepanolobium, more commonly known as Acacia drepanolobium or whistling thorn, is a swollen-thorn acacia native to East Africa. The whistling thorn grows up to 6 meters tall. It produces a pair of straight spines at each node, some of which have large bulbous bases. These swollen spines are naturally hollow and occupied by any one of several symbiotic ant species. The common name of the plant is derived from the observation that when wind blows over bulbous spines in which ants have made entry and exit holes, they produce a whistling noise. Symbiosis with ants Like other acacias, whistling thorns have leaves that contain tannins, which are thought to serve as deterrents to herbivory. Like all African acacias, they are defended by spines. In addition, whistling thorn acacias are myrmecophytes that have formed a mutualistic relationship with some species of ants. In exchange for shelter in the bulbous spines (domatia) and nectar secretions, these ants appear to defend the tree against herbivores, such as elephants and giraffes, as well as herbivorous insects. At a site in Kenya, three Crematogaster and one Tetraponera ant species compete for exclusive possession of individual whistling thorn trees: Crematogaster mimosae, Crematogaster sjostedti, Crematogaster nigriceps and Tetraponera penzigi (Young et al., 1996; Palmer et al., 2008). Ant species vary in their level of mutualism with whistling thorn trees. The most common ant symbiote (~ 50% of trees), C. mimosae, has the strongest mutualistic relationship, aggressively defending trees from herbivores while relying on swollen-spines for shelter and feeding from nectar produced by glands near the base of leaves. Because the ants compete for exclusive usage of a given tree, some species employ tactics to reduce the chance of a hostile ant invasion. Crematogaster nigriceps trim the buds of trees to reduce their lateral growth, thereby reducing chances of contact with a neighbouring tree occupied by a rival colony. Tetraponera penzigi, the only species which does not utilise the nectar produced by the trees, instead destroys the nectar glands to make a tree less appealing to other species. The symbiotic relationship between the trees and the ants appears to be maintained by the effects of browsing by large herbivores. At the site in Kenya, when large herbivores were experimentally excluded, trees reduced the number of nectar glands and swollen spines they provided to ants. In response, the usually dominant C. mimosae increased their tending of parasitic sap-sucking insects as a replacement food source. In addition, the number of C. mimosae-occupied trees declined while twice as many become occupied by C. sjostedti, a much less aggressive defender of trees. Because C. sjostedti benefits from the holes made by boring beetle larvae, this species facilitates parasitism of trees by the beetles. As a result, the mutualistic relationship between whistling thorn trees and resident ants breaks down in the absence of large herbivores, and trees become paradoxically less healthy as a result (Palmer et al., 2008) and become much more vulnerable should herbivores be reintroduced. References Palmer, T.M., Stanton, M.L., Young, T.P., Goheen, J.R., Pringle, R.M., Karban, R. 2008. Breakdown of an Ant–Plant Mutualism Follows the Loss of Large Herbivores from an African Savanna. Science 319(5860): 192–195 (doi:10.1126/science.1151579). Young, T.P., Stubblefield, C.H., Isbell, L.A. 1996. Ants on swollen-thorn acacias: Species coexistence in a simple system. Oecologia 109(1): 98–107 (doi:10.1007/s004420050063).

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• nigriceps. Crematogaster nigriceps Emery, 1897e: 600, fig. (w.) SOMALIA, ETHIOPIA.
  • Type-material: syntype workers (number not stated).
  • Type-localities: Somalia: Banas (E. dei P. Ruspoli) (invalid restriction of type-locality by Wheeler, W.M. 1922a: 842; no lectotype designated), Ethiopia: Hauacio (E. dei P. Ruspoli).
  • Type-depository: MSNG.
  • Viehmeyer, 1923: 89 (q.m.).
  • Combination in C. (Crematogaster): Wheeler, W.M. 1922a: 842;
  • combination in C. (Acrocoelia): Emery, 1922e: 148.
  • Subspecies of auberti: Finzi, 1940: 160.
  • Status as species: Emery, 1922e: 148; Wheeler, W.M. 1922a: 842; Viehmeyer, 1923: 89; Menozzi & Consani, 1952: 65; Bolton, 1995b: 158; Hita Garcia, et al. 2013: 211; Borowiec, L. 2014: 67 (see note in bibliography).
  • Distribution: Ethiopia, Israel, Kenya, Libya, Somalia, Sudan.
  • Current subspecies: nominal plus prelli, saganensis.

Taxonomic Notes

Taylor & McGavin (2020) treat the subspecies Crematogaster nigriceps prelli and Crematogaster nigriceps saganensis as synonyms of this species but provide no justification. Further studies are needed to confirm the true status for these taxa.

References

• Borowiec, L. 2014. Catalogue of ants of Europe, the Mediterranean Basin and adjacent regions (Hymenoptera: Formicidae). Genus (Wroclaw) 25(1-2): 1-340.
• Emery, C. 1897f. Formiche raccolte da Don Eugenio dei Principi Ruspoli, durante l'ultimo suo viaggio nelle regioni dei Somali e dei Galla. Ann. Mus. Civ. Stor. Nat. 38[=(2(18): 595-605 (page 600, fig. worker described)
• Emery, C. 1922c. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [part]. Genera Insectorum 174B: 95-206 (page 148, Combination in C. (Acrocoelia))
• Heterick, B.E. 2021. A guide to the ants of Western Australia. Part I: Systematics. Records of the Western Australian Museum, Supplement 86, 1-245 (doi:10.18195/issn.0313-122x.86.2021.001-245).
• Heterick, B.E. 2022. A guide to the ants of Western Australia. Part II: Distribution and biology. Records of the Western Australian Museum, supplement 86: 247-510 (doi:10.18195/issn.0313-122x.86.2022.247-510).
• Martins, D.J. 2010. Not all ants are equal: obligate acacia ants provide different levels of protection against mega-herbivores. African Journal of Ecology 48, 1115–1122 (doi:10.1111/j.1365-2028.2010.01226.x).
• Sensenig, R. L., D. K. Kimuyu, J. C. Ruiz Guajardo, K. E. Veblen, C. Riginos, and T. P. Young. 2017. Fire disturbance disrupts an acacia ant–plant mutualism in favor of a subordinate ant species. Ecology. 98:1455-1464. doi:10.1002/ecy.1797
• Taylor, B., McGavin, G. 2020. Ants found on acacia of the genus Vachellia. Belgian Journal of Entomology 99: 1-47.
• Viehmeyer, H. 1923. Wissenschaftliche Ergebnisse der mit Unterstützung der Akademie der Wissenschaften in Wien aus der Erbschaft Treitl von F. Werner unternommenen zoologischen Expedition nach dem anglo-ägyptischen Sudan (Kordofan) 1914. VII. Hymenoptera (page 89, queen, male described)
• Ward, P.S., Downie, D.A. 2005. The ant subfamily Pseudomyrmecinae (Hymenoptera: Formicidae): phylogeny and evolution of big-eyed arboreal ants. Systematic Entomology 30:310-335 (doi:10.1111/j.1365-3113.2004.00281.x).
• Wheeler, W. M. 1922j. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bull. Am. Mus. Nat. Hist. 45: 711-1004 (page 842, Combination in C. (Crematogaster))

References based on Global Ant Biodiversity Informatics

• Borowiec L. 2014. Catalogue of ants of Europe, the Mediterranean Basin and adjacent regions (Hymenoptera: Formicidae). Genus (Wroclaw) 25(1-2): 1-340.
• Izhaki I., B. Idelovich, R. Laster, and Y. Ofer. 2009. The impact of macro- vs micro environmental factors on the structure of ant communities inhabiting East-Mediterranean Aleppo pine forests. Israel Journal of Entomology 39: 129-146.
• Soulié J., and L. D. Dicko. 1965. La répartition des genres de fourmis de la tribu des "Cremastogastrini" dans la faune éthiopienne et malgache. Hymenoptera - Formicoidea - Myrmicidae. Ann. Univ. Abidjan Sér. Sci. 1: 85-106.
• Stanton, M.L., T.M. Palmer and T.P. Young. 2002. Competition-Colonization Trade-Offs in a Guild of African Acacia-Ants. Ecological Monographs 72(3):347-363
• Stanton, M.L., T.M. Palmer and T.P. Young. 2005. Ecological barriers to early colony establishment in three coexisting acacia-ant species in Kenya. Insectes Sociaux 52:393-401
• Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004