The Wasmannia auropunctata (also called the small ant of fire or electric ant , because of very irritant puncture) is a species of invasive Fourmi being able to form Supercolonie S.
Mode of reproduction
Researchers French and Suisse S explain the strange reproductive strategy of Wasmannia auropunctata. In this mode of reproduction ever observed before, the males are the clones of their father and the queens are the clones of their mother.
" At the majority of the species of ants, the queens manufacture two types of egg " , explains Denis Fournier, first author of the study and in charge of research to the Fonds national of the scientific research (FNRS) of Belgium. " Some, known as Haploid S, not fertilized, produce males while others, said Diploïde S, are fertilized and produce either of the queens, or of the workers. " But in the small ant of fire, the queens, little by little, learned how to do without the seed from the males to generate other queens, thus transmitting the totality of their Genetic inheritance to the following generation of reproductive females.
Blow, the males do not transmit any more their genes but to the workers, who, sterile, cannot ensure the perenniality of this genetic inheritance. To thwart this " hegemonism génétique" queens, the males owed ruser. The males fertilize the haploid ovules and once fecundation carried out, the DNA of the male eliminates that from the female. The egg in question generates, ultimately, a clone of the male having fertilized it.
To Wasmannia auropunctata, all or almost thus occurs like if the males and the females belonged to two different species. However, even if this divorce, soup of long time, the place on two branches distinct from the tree of the evolution, males and queens have despite everything need one for the other. Their genes mix thus to generate the workers. Although deads, these last do not ensure of it less the social organization of the species and the good performance of the colonies.
Without being finalist, one could see one of the explanations there on the fact that, although equipped with wings in their youth, the queens and the males never make nuptial flight. Moreover, it was shown that the queens survive badly without the assistance of some workers (who do not have wings).
Invasion of Africa
Since its introduction to the Gabon, by agronomists in the Years 1920, Wasmannia auropunctata invades now several countries of central Africa and threatens the Biodiversité.
An investigation was led into its current distribution to Cameroun. Nests were collected in each infested locality and were raised at the laboratory for one month. Tests of aggressiveness consisting with confrontations with one of the workers coming from same nests, of the same localities or of different localities were led in boxes of Petri (Ø = 1,5 cm). The observations were made under a binocular magnifying glass (x16). During five minutes, the predefined behaviors were recorded and classified according to a scale of increasing aggressiveness on four levels: 1 = fortuitous contact, antennation short, antennation mutual, to remain motionless in contact with congeneric, trophallaxie, 2 = prolonged antennation, continuation, avoidance, 3 = seized, 4 = combat, agrippement. The results obtained show that the zone infested by W. auropunctata extended from approximately 120 km and 300 km respectively towards the South and the North of the zone of introduction. Aggressiveness was absent inside the same nest, weak inside the same locality and between the localities. These results indicate that only one supercolonie exists in Cameroun.
Invasion of French Polynesia
Wasmannia auropuncata was probably not introduced voluntarily in Tahiti, but its expansion is from now on in the course of description and of control, because as it already showed, it threatens the local biodiversity. In addition, several animals make already the expenses of its attacks.
See too
External references
External bonds
- Photograph gallery
- complete presentation of the ant of the ISSG
- the cloning: the ecological success of the ant W. auropunctata By Eric Geirnaert.
- Wasmannia in Tahiti Site centralizing information on the invasion of W. auropunctata in French Polynesia.
- Fenua Animalia Site summarizing of information on the invasion of W. auropunctata in French Polynesia.
- Fenua Animalia Site summarizing information one the French Polynesia invasion by W. auropunctata.
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