Ooceraea biroi, the clonal raider ant, is a queenless clonal ant in
Ooceraea (recently transferred from the genus
Cerapachys). Native to the Asian mainland, this species has
become invasive on tropical and subtropical islands throughout the
world. Unlike most ants, which have reproductive queens and mostly
nonreproductive workers, all individuals in a O. biroi colony
reproduce clonally via thelytokous parthenogenesis. Like most
dorylines, O. biroi are obligate myrmecophages and raid nests of other
ant species to feed on the brood.
2 Cyclic life history
3 Genetics and genomics
5 External links
Clonal raider ants are small, about 2 mm long, but relatively
stocky. Like many former cerapachyines, O. biroi is heavily armored,
with the short, thick antennae which give the old subfamily its name
(from Greek, keras/κέρας, meaning horn and pachys/παχυς,
meaning thick). The other defining characteristic of the former
Cerapachyinae, a row of teeth over the pygidium (last visible
abdominal segment), is very small in O. biroi and difficult to see. O.
biroi can be distinguished from many other former cerapachyines by the
combination of highly reduced or nonexistent eyes, rectangular head,
and a distinct postpetiole.
Cyclic life history
Like many myrmecophagous ants, O. biroi exhibits synchronized
oviposition and cyclic behavior, shifting between a reproductive phase
and a foraging phase. The reproductive phase begins when a
cohort of larvae pupate and all the adults in the colony activate
their ovaries. Thelytokously produced eggs are then laid synchronously
after about four days and develop for roughly 10 days while the adults
remain within the nest, cleaning and tending the eggs and pupae. Eggs
hatch roughly two weeks into the reproductive phase, and then a few
days later, the foraging phase begins with emergence of new adults
from the pupae. Adults forage for the next two weeks, raiding the
nests of other ant species to bring back food for the larvae. The
cycle completes with the pupation of the new larval cohort and the
resumption of the reproductive phase.
Genetics and genomics
The effects of central fusion and terminal fusion on heterozygosity
Parthenogenesis is a natural form of reproduction in which growth and
development of embryos occur without fertilisation.
Thelytoky is a
particular form of parthenogenesis in which the development of a
female individual occurs from an unfertilized egg. Automixis is a form
of thelytoky, but different kinds of automixis are seen. The kind of
automixis relevant here is one in which two haploid products from the
same meiosis combine to form a diploid zygote. Because O. biroi can be
very easily maintained in laboratory conditions, it has attracted
attention as a potential model organism for studying the molecular
biology of sociality. Laboratory maintenance is made easy by the
clonality of the species; a few individuals placed in an airtight box
and given ant brood as food can be grown up into many large
colonies. Clonal reproduction is achieved by automixis with central
fusion (see diagram), as is common in the Hymenoptera, yet unlike most
clonal Hymenoptera, loss of heterozygosity is extraordinarily
slow. The upshot of this is that offspring are almost genetically
identical to the parent, allowing nearly complete control over the
genotype of experimental subjects. Finally, since O. biroi colonies
are queenless and all workers reproduce, generation time is about two
months (the developmental time of a single individual), rather than
many years as is the case for most ant species.
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Cerapachys biroi". Insectes Sociaux. 42:
^ F. Ravary; P Jaisson (2004). "Absence of individual sterility in
thelytokous colonies of the ant
Cerapachys biroi Forel (Formicidae,
Cerapachyinae)". Insectes Sociaux. 51: 67–73.
^ Hölldobler, Bert; Wilson, Edward O. (1990). The Ants. Belknap Press
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^ D.J.C. Kronauer (2009). "Recent advances in army ant biology
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^ a b c F. Ravary; P. Jaisson (2002). "The reproductive cycle of
thelytokous colonies of
Cerapachys biroi Forel (Formicidae,
Cerapachyinae)". Insectes Sociaux. 49: 114–119.
^ a b c P.R.O Oxley; L. Ji; I. Fetter-Pruneda; S.K. McKenzie; C. Li;
H. Hu; G. Zhang; D.J.C. Kronauer (2014). "The Genome of the Clonal
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Media related to
Cerapachys biroi at Wikimedia Commons