Biologists at the University of Arizona have identified an all-female species of ant, which has dispensed with sex.
The researchers have revealed that the ant species - Mycocepurus smithii - rely upon cloning for reproduction. They say that the queen ants copy themselves to produce genetically identical daughters.
According to the research team, this species cultivates a garden of fungus, which also reproduces asexually.
Biologist Anna Himler, who led the research, revealed that the research team used a battery of tests to verify their findings.
Upon "fingerprinting" DNA of the ant species, the researchers found them all to be clones of the colony's queen.
The researchers later dissected the female insects, and found them to be physically incapable of mating.
They said that an essential part of the ants' reproductive system, known as the "mussel organ", had degenerated.
While asexual reproduction of males from unfertilised eggs is a normal part of some insect reproduction, the researchers noted that such a process in females is "exceedingly rare in ants".
"In social insects, there are a number of different types of reproduction. But this species has evolved its own unusual mode," the BBC quoted Dr. Himler as saying.
She agreed that her team had yet to find out why the particular ant species had become fully asexual.
Her team are presently conducting more genetic experiments to find out how long ago the evolutionary change occurred.
Dr Himler has revealed that her interest in Mycocepurus smithii was originally sparked by their ability to cultivate crops.
"Ants discovered farming long before we did - they have been cultivating fungus gardens for an estimated 80 million years," she said.
While many different species of ant cultivate fungi, this particular species is able to grow "a greater number of crops than other ant species," she explained.
Since the fungus crop reproduces asexually, Dr. Himler thinks that it might give the ants some kind of advantage "not to operate under the usual constraints of sexual reproduction".
"There is certainly more work to be done in this system. We're quite excited about the direction this research might take us, and its implications," she said.
The study has been published in the journal Proceedings of the Royal Society B.