Ooceraea biroi

A small, inconspicuous ant that has spread around the world through human commerce.

Identification
Dias et al (2018) - The species appears robust with opaque body having closely spaced piligerous punctures and dense pilosity. The species displays a great variation in colour and we also observed that the colour of specimens mostly corresponds to the colour of soil they inhabit. Mandibles subtriangular, dentate; antennae 9-segmented; scapes short and clavate reaching up to half of posterior head margin; eyes and ocelli absent; anterior clypeal margin entire and convex; vertex deflexed and flat.

Distribution based on Regional Taxon Lists
Afrotropical Region: Comoros. Indo-Australian Region: Guam, Hawaii, Marshall Islands, Northern Mariana Islands, Philippines, Samoa, Singapore. Malagasy Region: Madagascar, Mayotte, Seychelles. Neotropical Region: Guadeloupe, Lesser Antilles, Puerto Rico, Trinidad and Tobago, Turks and Caicos Islands. Oriental Region: India, Nepal, Sri Lanka, Taiwan, Vietnam. Palaearctic Region: China, Japan.

Biology
Wetterer et al. (2012) - Cerapachys biroi has small colonies, typically consisting of a few hundred workers. Workers are only 2-3 mm in size and are entirely subterranean. Cerapachys biroi feeds primarily on the brood of other ants (Tsuji and Yamauchi, 1995), but also may consume the soft-bodied larvae of other insects (Wocott, 1948). Cerapachys workers have heavily sclerotized cuticle that protects them against attack or injury when raiding the broods of other ants (Holldobler, 1982).

The reproductive cycle of Cerapachys biroi is similar to that of some army ants in that C. biroi colonies produce brood in distinct cohorts, synchronized with cycles of alternating statary and nomadic phases (Ravary and Jaisson, 2002, Ravary et al., 2006). Cerapachys biroi has received particular attention because, unlike most ants, all workers can produce diploid eggs through thelytokous parthenogenesis, although workers differ in their number of ovaries and their potential reproductive output (Tsuji and Yamauchi, 1995, Ravary and Jaisson, 2004, Lecoutey et el., 2011). This means that any colony fragment can theoretically found a new population. It is possible that this method of reproduction has facilitated the spread of C. biroi around the world.



Ravary and Jaisson (2002) examined life-history attributes of laboratory colonies of O. biroi. They documented a biphasic reproductive cycle (Figure 1) similar to that of a few specie of well-studied army ants, e.g., Eciton burchellii). There are two alternating phases of adult activity, a foraging phase and statary phase. Brood development is synchronous and larvae develop through three instars. The transition from the foraging to statary phase occurs when the brood are in the pupal stage and do not need to be fed. A new cohort of brood is produced by the now idled foragers, with virgin workers laying diploid eggs. The statary phase ends with the callow workers emerging as adults and the eggs hatch. The adult workers begin again to forage for food. This provides the food resources needed by the synchronously maturing larvae.

Nomenclature

 *  biroi. Cerapachys (Syscia) biroi Forel, 1907a: 7 (w.) SINGAPORE.
 * Imai, et al. 1984: 5 (k.).
 * Combination in Ooceraea: Borowiec, M.L. 2016: 198.
 * Status as species: Emery, 1911d: 10; Chapman & Capco, 1951: 20; Brown, 1975: 22; Ogata, 1983: 136; Terayama, et al. 1988: 38; Morisita, et al. 1989: 31; Bolton, 1995b: 142; Tang, Li, et al. 1995: 25; Wu, J. & Wang, 1995: 48; Imai, et al. 2003: 210; Clouse, 2007b: 203; Framenau & Thomas, 2008: 58; Terayama, 2009: 122 (in key); Bharti & Akbar, 2013a: 82 (in key); Bharti & Wachkoo, 2013d: 1192 (in key); Chen, Shi & Zhou, 2016: 9 (in key).
 * Senior synonym of ierensis: Brown, 1975: 22, 73.
 * Senior synonym of seini: Brown, 1975: 22, 73.
 * Senior synonym of silvestrii: Brown, 1975: 22, 73.
 * Senior synonym of sinensis: Brown, 1975: 22, 73.
 * silvestrii. Cerapachys (Syscia) silvestrii Wheeler, W.M. 1909c: 269 (w.) HAWAII.
 * Status as species: Emery, 1911d: 10; Wheeler, W.M. 1935g: 8; Wilson & Taylor, 1967: 33.
 * Senior synonym of seini: Wilson & Taylor, 1967: 33.
 * Junior synonym of biroi: Brown, 1975: 22.
 * ierensis. Cerapachys (Syscia) ierensis Weber, 1939a: 94 (w.) TRINIDAD.
 * Status as species: Kempf, 1972a: 76.
 * Junior synonym of biroi: Brown, 1975: 22.
 * seini. Cerapachys (Syscia) seini Mann, 1931: 440, fig. 1 (w.) PUERTO RICO.
 * Status as species: Smith, M.R. 1937: 823; Kempf, 1972a: 76.
 * Junior synonym of silvestrii: Wilson & Taylor, 1967: 33.
 * Junior synonym of biroi: Brown, 1975: 22.
 * sinensis. Cerapachys (Syscia) sinensis Wheeler, W.M. 1928c: 3 (w.) CHINA.
 * Status as species: Chapman & Capco, 1951: 20.
 * Junior synonym of biroi: Brown, 1975: 22.