Anoplolepis custodiens
Anoplolepis custodiens, the Common Pugnacious Ant, is a robust reddish-brown formicine native to Sub-Saharan Africa where it is considered a major indigenous pest. Although A. custodiens is not known to have established populations outside of its native range, the species is occasionally intercepted at ports of entry in the United States. A suite of life-history traits suggest A. custodiens could become a serious pest if it were to establish outside of its native range.
Anoplolepis custodiens is a relatively well studied species because of its impact on agricultural systems (especially vineyards) in South Africa (Addison & Samways, 2006). In its natural habitat in the southern Karoo, this ant nests in open, well insulated soil and feeds on dead and live animal matter as well as honeydew and nectar (Dean, 1992). The species is polygynous, highly aggressive, and is known to exhibit extreme dominance over other ant species in agricultural landscapes (Samways, 1990), especially when honeydew food resources are available. The lack of intra-specific aggression among colonies has been noted in previous studies (Steyn, 1954; Way, 1953), and is thought to facilitate invasive expansions at the local scale. It has been suggested that A. custodiens has the potential to become a serious invader of open-canopy, subtropical countries outside Africa, and should receive quarantine attentiveness by non-African nations (Addison & Samways, 2006; Samways, 1999). The species is known from South Africa, Zanzibar and Tanzania, Democratic Republic of Congo, Angola and the ‘Ethiopian region’ (Addison & Samways, 2006), and determined specimens from Antweb are also listed from Swaziland.
A suite of life-history traits suggest A. custodiens could become a serious pest if it were to establish outside of its native range.
Diagnosis of worker among Antkey species. Polymorphic worker caste. Antenna 11-segmented. Antennal club indistinct. Antennal scape length less than 1.5x head length. Eyes large; do not break outline of head. Antennal sockets and posterior clypeal margin separated by a distance equal to or greater than the minimum width of antennal scape. Dorsum of mesosoma with metanotal impression, but never with a deep and broad concavity. Propodeum and petiolar node both lacking a pair of short teeth. Propodeum lacking posteriorly projecting protrusion. Metapleuron with a distinct gland orifice. Propodeal declivity less than twice length of propodeal dorsum. Waist 1-segmented. Petiole upright and not appearing flattened. Gaster armed with acidopore. Distinct constriction not visible between abdominal segments 3+4. Hairs not long thick and produced in pairs. Yellowish-brown to reddish-brown with a darker gaster. Polymorphic worker caste.
Anoplolepis custodiens is most easily confused with Anoplolepis gracilipes, but can be readily distinguished by the shorter antennal scapes and by the eyes that do not break the outline of the head.
Anoplolepis gracilipes
Native range. Southern Africa. South Africa, Zanzibar and Tanzania, Democratic Republic of Congo, Angola and the Ethiopian region, and determined specimens from Antweb are also listed from Swaziland.
Introduced range. Not yet established outside its native range.