| Cardiocondyla nigra|
One databased worker specimen was collected from a thorn bush. Nothing else is know about the biology of Cardiocondyla nigra.
Seifert (2003) - A member of the Cardiocondyla batesii group. Differs from Cardiocondyla batesii by the steeper, more acute, and in lateral view more narrow based spines and the lower SPBA/CS with 0.257 ± 0.009 [0.242, 0.271] in C. batesii and 0.231 ± 0.013 [0.199, 0.257] in nigra. The pigmentation contrast between head and mesosoma is significantly larger in C. batesii, but is no reliable discriminator because of the occasional occurrence of homogeneously dark specimens.
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Distribution based on Regional Taxon Lists
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Little is known about Cardiocondyla nigra. Until further studies reveal more about this species we can infer that its natural history and biology is likely similar to other members of the genus. Seifert revised the holarctic species of Cardiocondyla in 2003 and the following synopsis is based on his excellent treatment of the genus. References to other publications and more details about what is reported here can be found in Seifert (2003).
Many Cardiocondyla species inhabit areas that experience frequent disturbance and/or are quite open. These may be human altered areas, where a number of Cardiocondyla tramp species thrive, but also natural areas such as semi deserts and steppes, immature soils at rivers, lakes, and sea shores and to a lesser extent forest margins or burned-down woodland patches. In contrast to this open-land group, the natural habitat affinities of many tropical species are primary rain forests.
Nests are typically in soil and sometimes under stones. Two species are known to nest in vegetation but this is unusual for the genus. The single nest entrances is small (1-1.5 mm) and inconspicuous. In the desert nests can be relatively deep (> 1m) and have many chambers but in areas where conditions are less extreme there is generally a single chamber (15-20 mm diameter and 3-4 mm height) that is not far below the ground surface (2-15 cm).
Cardiocondyla tramp species (Cardiocondyla wroughtonii, Cardiocondyla obscurior, Cardiocondyla mauritanica, Cardiocondyla emeryi and Cardiocondyla minutior) are known to be polygynous, as are some less widespread species, while other species are known to be monogynous.
Cardiocondyla ants are omnivorous. Zoophagy (zoo necrophagy and killing of small weakly sclerotised arthropods), granivory, and nectarivory have also been noted. Tandem running has been observed as a method of recruitment to food sources in a few species.
Intranidal mating appears to be the norm for most species in the genus. Mating strategies are species dependent and may take various forms. Winged males may mate within their nest or fly to and enter other colonies to mate. Queen mate intranidally and fly from their nest to begin a new colony, become integrated into their natal colony, or may walk away from their nest and establish a new colony nearby.
Cardiocondyla are unusual in having peculiar male forms. Male polymorphism is found in some species with typical males and an ergatoid form. These latter males are wingless and worker like in appearance. Ergatoid males fight with other males within their natal nest. By killing potential rival males, a dominant male can monopolize matings with the virgin queens in their colony. Morphological modifications that enhance the fighting abilities of ergatoid males have been documented, e.g., modified mandibles well suited to fighting and increased mesosomal size for better protection against attacks from rivals. Another unusual characteristic of ergatoid males is the continuation of spermatogenesis throughout their adult life. Males of most aculeate hymenoptera stop producing sperm once they are fully mature.
Some species are known to produce different queen morphs. This presumably facilitates there being a longer range dispersal queen form and a shorter or non-dispersing form. Gyne polymorphism appears to be an adaptation for species inhabiting continental desert or semi-desert habitats. The cosmopolitan tramp species, on the other hand, do not exhibit this gyne polymorphism.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- nigra. Cardiocondyla batesii var. nigra Forel, 1905b: 174 (w.q.) TUNISIA. Santschi, 1907: 324 (m. ergatoid m. and gynandromorph). Raised to species: Schembri & Collingwood, 1981: 428. Junior synonym of batesii: Radchenko, 1995b: 451. Revived from synonymy and senior synonym of torretassoi: Seifert, 2003a: 240.
- torretassoi. Cardiocondyla elegans var. torretassoi Finzi, 1936: 167 (w.) EGYPT. Raised to species: Radchenko, 1995b: 451. Junior synonym of nigra: Seifert, 2003a: 240.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Seifert (2003) - Head of medium length, CL/CW 1.172. Postocular distance very small, PoOc/CL 0.366. Occipital margin slightly excavated. Eyes large, EYE 0.266. Frontal carinae immediately posterior of FRS level converging. Lateral clypeus longitudinally carinulate. Dorsal area of head almost without longitudinal sculpture; weak longitudinal carinulae present on and posterior of frontal laminae. Vertex with very shallow and simple foveolae of 14 - 19 mm diameter, their internal surface micro-corrugated; foveolar interspaces wider than foveolar diameter, moderately shining, and with fine cross-branched or semi-reticulate microstructures. Dorsum of mesosoma and waist moderately shining and finely microreticulate. Propodeal spines rather short, steep, and acute. Petiole profile with relatively long peduncle and relatively small node, which is in dorsal view about as long as wide. Postpetiolar sternites without any flat bulge. Whole body usually concolorous dark to blackish brown, specimens with distinctly lighter mesosoma occasionally occur.
Seifert (2003) - Head of medium length, CL/CW 1.170. Postocular index very small, PoOc/CL 0.376. Occipital margin straight or weakly concave. Dorsal area of head almost without longitudinal sculpture; very weak longitudinal carinulae present on and posterior of frontal laminae. Vertex with very shallow and simple foveolae of 16 - 18 mm diameter; interspaces as wide as foveolar diameter, shining, with fine cross-branched microstructures. Dorsal area of mesosoma foveolate; interspaces between foveolae shining, wider than foveolar diameter and with fine cross-branched microstructures. Lateral area of mesosoma shining, finely reticulate-carinulate, lateral metapleuron longitudinally rugulose. Propodeal spines rather short. Petiole node in dorsal view as wide as long, usually circular; dorsal and lateral petiole shape frequently as depicted for the type of Cardiocondyla nigra, but conditions similar to that of the Cardiocondyla batesii type do occur. Whole body concolorous dark brown. Gynes from Tunisia: Lac Kelbia- 1935.03 brachypterous, with forewing length 1350 - 1400 mm.
Tunisia [types investigated]. Cardiocondyla nigra: 5 syntype workers and 5 syntype gynes labelled “C. Batesii For. var. nigra, Kairouan (Santschi) 159”, Musee d'Histoire Naturelle Genève.
- Forel, A. 1905e. Miscellanea myrmécologiques II (1905). Ann. Soc. Entomol. Belg. 49: 155-185 (page 174, worker, queen described)
- Radchenko, A. G. 1995g. Palearctic ants of the genus Cardiocondyla (Hymenoptera, Formicidae). Entomol. Obozr. 74: 447-455 (page 451, Junior synonym of batesii)
- Santschi, F. 1907. Fourmis de Tunisie capturées en 1906. Rev. Suisse Zool. 15: 305-334 (page 324, male, erqatoid male and gynandromorph described)
- Seifert, B. 2003. The ant genus Cardiocondyla (Insecta: Hymenoptera: Formicidae) - a taxonomic revision of the C. elegans, C. bulgarica, C. batesii, C. nuda, C. shuckardi, C. stambuloffii, C. wroughtonii, C. emeryi, and C. minutior species groups. Annalen des Naturhistorischen Museums in Wien Serie B Botanik und Zoologie. 104:203-338. PDF (page 240, Revived from synonymy and senior synonym of torretassoi)