Cardiocondyla

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.

Identification
Seifert's 2003 Cardiocondyla revision includes a key to the holarctic species.

Biology
The biology of most Cardiocondyla species remain largely unstudied. 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.

Castes
Ergatoid males and queens are present in some species.

Nomenclature

 *  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.

Additional References

 * [[Media:Bernard 1956c.pdf|Bernard, F. 1956c. Révision des fourmis paléarctiques du genre Cardiocondyla Emery. Bull. Soc. Hist. Nat. Afr. Nord 47: 299-306 PDF]]
 * [[Media:Heinze, J., Cremer, S., Eckl, N. & Schrempf, A. 2006. Stealthy invaders the biology of Cardiocondyla tramp ants.pdf|Heinze, J., Cremer, S., Eckl, N. & Schrempf, A. 2006. Stealthy invaders the biology of Cardiocondyla tramp ants. Insect. Soc. 53, 1–7.]]