Cardiocondyla are tiny myrmicine ants which live in colonies consisting of several dozen to a few hundred workers. Queen number varies by species. Nests are commonly in the soil, less so under rocks and in just a few species are known to be made in vegetation. Open arid habitats are favored by many Cardiocondyla. Several species are well known tramp species (Seifert, 2003).
Bolton (1982) - Small to minute monomorphic myrmicine ants. Mandibles with 5 teeth which decrease in size from apical to basal. Palp formula 5, 3 (16 species examined). Clypeus with flattened and prominent projecting lateral portions which are fused to the raised projecting median portion to form a shelf which projects forward over the mandibles. Sometimes the lateral portions of the clypeus extend further forward than the median so that the anterior margin of the projecting shelf is concave medially. Median portion of clypeus posteriorly broadly inserted between small narrow frontal lobes. Frontal carinae and antennal scrobes absent. Eyes present, generally large and conspicuous, situated in front of the midlength of the sides. Antennae with 11-12 segments, usually with a distinct 3-segmented club but the first club segment may be relatively small. Promesonotal dorsum flattened to evenly convex in profile, the dorsal alitrunk without sutures but the metanotal groove commonly (but by no means universally) impressed. Pronotal corners in dorsal view broadly rounded to bluntly angular and projecting. Propodeal spiracle small, situated approximately at the midlength, often low down on the side but not shifted back towards the margin of the declivity. Propodeum unarmed to strongly bispinose. Metapleurallobes low and rounded. Petiole nodiform with a moderate to long, usually slender, anterior peduncle. Postpetiole dorsoventrally flattened in profile, in dorsal view very broad, much broader than the petiole node. Sting large and strongly developed, knife blade-like and broad in profile, without lamelliform appendages. Dorsal surfaces of body usually hairless.
Cardiocondyla is still separated from Leptothorax and its close relatives by the characters devised by Emery and Wheeler, namely the specialized form of the anterior clypeus (although this is hinted at in some Leptothorax), the characteristic form of the postpetiole and the reduced wing venation of the females. A further character distinguishing the two is the specialized blade-like sting of Cardiocondyla, not seen in Leptothorax.
- Key to Afrotropical Cardiocondyla workers
- Key to Australian Cardiocondyla
- Key to Holartic Cardiocondyla
- Key to US Cardiocondyla species
Distribution and Richness based on AntMaps
The biology of most Cardiocondyla species has not been studied. 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.
Ergatoid males and queens are present in some species.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- CARDIOCONDYLA [Myrmicinae: Formicoxenini]
- Cardiocondyla Emery, 1869b: 20. Type-species: Cardiocondyla elegans, by monotypy.
- Cardiocondyla senior synonym of Emeryia: Forel, 1892h: 461; Forel, 1892i: 313.
- Cardiocondyla senior synonym of Xenometra: Baroni Urbani, 1973: 200; Marikovsky & Yakushin, 1974: 60.
- Cardiocondyla senior synonym of Dyclona, Loncyda, Prosopidris: Smith, D.R. 1979: 1375; Bolton, 1982: 309.
- DYCLONA [junior synonym of Cardiocondyla]
- Dyclona Santschi, 1930b: 70 (footnote) [as subgenus of Cardiocondyla]. Type-species: Monomorium cristatum, by original designation.
- Dyclona junior synonym of Cardiocondyla: Bolton, 1982: 309.
- EMERYIA [junior synonym of Cardiocondyla]
- Emeryia Forel, 1890b: cx. Type-species: Emeryia wroughtonii, by monotypy.
- Emeryia junior synonym of Cardiocondyla: Forel, 1892h: 461; Forel, 1892i: 313.
- LONCYDA [junior synonym of Cardiocondyla]
- Loncyda Santschi, 1930b: 70 [as subgenus of Cardiocondyla]. Type-species: Cardiocondyla (Loncyda) monardi, by monotypy.
- Loncyda junior synonym of Cardiocondyla: Bolton, 1982: 309.
- PROSOPIDRIS [junior synonym of Cardiocondyla]
- Prosopidris Wheeler, W.M. 1935b: 40 [as subgenus of Cardiocondyla]. Type-species: Cardiocondyla (Prosopidris) sima, by original designation.
- Prosopidris raised to genus: Reiskind, 1965: 80.
- Prosopidris junior synonym of Cardiocondyla: Bolton, 1982: 309.
- XENOMETRA [junior synonym of Cardiocondyla]
- Xenometra Emery, 1917a: 96. Type-species: Xenometra monilicornis (junior synonym of Cardiocondyla emeryi), by monotypy.
- Xenometra junior synonym of Cardiocondyla: Baroni Urbani, 1973: 199; Marikovsky & Yakushin, 1974: 60.
- Arnold, G. 1916. A monograph of the Formicidae of South Africa. Part II. Ponerinae, Dorylinae. Ann. S. Afr. Mus. 14: 159-270 (page 200, Cardiocondyla in Myrmicinae, Cardiocondylini)
- Ashmead, W. H. 1905c. A skeleton of a new arrangement of the families, subfamilies, tribes and genera of the ants, or the superfamily Formicoidea. Can. Entomol. 37: 381-384 (page 383, Cardiocondyla in Myrmicinae, Stenammini)
- Baroni Urbani, C. 1973a. Die Gattung Xenometra, ein objektives Synonym (Hymenoptera, Formicidae). Mitt. Schweiz. Entomol. Ges. 46: 199-201 (page 200, Cardiocondyla senior synonym of Xenometra)
- Bernard, F. 1956c. Révision des fourmis paléarctiques du genre Cardiocondyla Emery. Bull. Soc. Hist. Nat. Afr. Nord 47: 299-306 PDF (page 299, Revision of Palearctic species)
- Bolton, B. 1982. Afrotropical species of the myrmecine ant genera Cardiocondyla, Leptothorax, Melissotarsus, Messor and Cataulacus (Formicidae). Bulletin of the British Museum (Natural History). Entomology, 46: 307-370 (page 309, Cardiocondyla senior synonym of Dyclona, Loncyda, and Prosopidris; page 311, Cardiocondyla in Myrmicinae, Leptothoracini)
- Bolton, B. 1994. Identification guide to the ant genera of the world. Cambridge, Mass.: Harvard University Press, 222 pp. (page 105, Cardiocondyla in Myrmicinae: Formiccoxenini)
- Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 244, Cardiocondyla in Myrmicinae: Formiccoxenini)
- Dalla Torre, K. W. von. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. 7. Formicidae (Heterogyna). Leipzig: W. Engelmann, 289 pp. (page 70, Cardiocondyla in Myrmicinae)
- Dlussky, G. M.; Fedoseeva, E. B. 1988. Origin and early stages of evolution in ants. Pp. 70-144 in: Ponomarenko, A. G. (ed.) Cretaceous biocenotic crisis and insect evolution. Moskva: Nauka, 232 pp. (page 80, Cardiocondyla in Myrmicinae, Cardiocondylini (anachronism))
- Emery, C. 1869b. Enumerazione dei formicidi che rinvengonsi nei contorni di Napoli con descrizioni di specie nuove o meno conosciute. Ann. Accad. Aspir. Nat. Secunda Era 2: 1-26 (page 20, Cardiocondyla as genus)
- Emery, C. 1877b. Saggio di un ordinamento naturale dei Mirmicidei, e considerazioni sulla filogenesi delle formiche. Bull. Soc. Entomol. Ital. 9: 67-83 (page 81, Cardiocondyla in Myrmicinae [Myrmicidae])
- Emery, C. 1895l. Die Gattung Dorylus Fab. und die systematische Eintheilung der Formiciden. Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 685-778 (page 769, Cardiocondyla in Myrmicinae, Myrmicini)
- Emery, C. 1914e. Intorno alla classificazione dei Myrmicinae. Rend. Sess. R. Accad. Sci. Ist. Bologna Cl. Sci. Fis. (n.s.) 18: 29-42 (page 40, Cardiocondyla in Myrmicinae, Cardiocondylini)
- Emery, C. 1922c. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [part]. Genera Insectorum 174B: 95-206 (page 124, Cardiocondyla in Myrmicinae, Cardiocondylini)
- Emery, C.; Forel, A. 1879. Catalogue des Formicides d'Europe. Mitt. Schweiz. Entomol. Ges. 5: 441-481 (page 456, Cardiocondyla in Myrmicinae [Myrmicidae])
- Forel, A. 1892h. Le mâle des Cardicondyla [sic] et la reproduction consanguine perpétuée. Ann. Soc. Entomol. Belg. 36: 458-461 (page 461, Cardiocondyla senior synonym of Emeryia)
- Forel, A. 1892j. Die Ameisenfauna Bulgariens. (Nebst biologischen Beobachtungen.). Verh. K-K. Zool.-Bot. Ges. Wien 42: 305-318 (page 313, Cardiocondyla senior synonym of Emeryia)
- Forel, A. 1917. Cadre synoptique actuel de la faune universelle des fourmis. Bull. Soc. Vaudoise Sci. Nat. 51: 229-253 (page 242, Cardiocondyla in Myrmicinae, Cardiocondylini)
- Heinze, J., Cremer, S., Eckl, N. & Schrempf, A. 2006. Stealthy invaders the biology of Cardiocondyla tramp ants. Insect. Soc. 53, 1–7.
- Jaffe, K. 1993. El mundo de las hormigas. Baruta, Venezuela: Equinoccio (Ediciones de la Universidad Simón Bolívar), 188 pp. (page 10, Cardiocondyla in Myrmicinae, Cardiocondylini (anachronism))
- Kusnezov, N. 1964 . Zoogeografía de las hormigas en Sudamérica. Acta Zool. Lilloana 19: 25-186 (page 57, Cardiocondyla in Myrmicinae [Myrmicidae] (anachronism))
- Marikovsky, P. I.; Yakushkin, V. T. 1974. The ant Cardiocondyla uljanini Em., 1889 and the systematic status of the "Xenometra parasitic ant". Izv. Akad. Nauk Kaz. SSR Ser. Biol. 3: 57-62 (page 60, Cardiocondyla senior synonym of Xenometra)
- Seifert, B. 2003a. 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. Ann. (page 203, Cardiocondyla revision)
- Smith, D. R. 1979. Superfamily Formicoidea. Pp. 1323-1467 in: Krombein, K. V., Hurd, P. D., Smith, D. R., Burks, B. D. (eds.) Catalog of Hymenoptera in America north of Mexico. Volume 2. Apocrita (Aculeata). Washington, D.C.: Smithsonian Institution Pr (page 1375, Cardiocondyla senior synonym of Dyclona, Loncyda, Prosopidris)
- Wheeler, W. M. 1910b. Ants: their structure, development and behavior. New York: Columbia University Press, xxv + 663 pp. (page 139, Cardiocondyla in Myrmicinae, Myrmicini)
- Wheeler, W. M. 1922i. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VII. Keys to the genera and subgenera of ants. Bull. Am. Mus. Nat. Hist. 45: 631-710 (page 661, Cardiocondyla in Myrmicinae, Cardiocondylini)