The yellow crazy ant, according to a paper published Thursday in the journal Science, lives up to its name. The acid-spraying insect has a bizarre form of reproduction unseen until now in the animal kingdom, one that may have allowed it to become one of the world’s worst invasive species, devastating many of the delicate ecosystems it encounters.
A quick refresher from your sex-ed class: Normally, an embryo — in everything from humans down to the simplest multicellular animal — develops after a sperm fertilizes an egg. That single, fused cell divides to form an organism made up of genetically identical cells. Pluck nearly any cell from your body, and you should see the same DNA as you would in any other cell.
Rather than fusing together, the genetic material from a queen’s egg and her mate’s sperm do not mix when forming a new male. Instead, the female and male ant both contribute DNA-laden nuclei, which begin replicating separately over and over again. These form into cells, which then become bound up in an embryo.
As a result, the bodies of male yellow crazy ants are not composed of cells containing the same set of DNA. The male ants are instead made up of two cell lines each with its own distinct genetic lineages — one from the queen and the other from her mate. The species’ queens and female workers, by contrast, form from a regular sperm-egg combination.
“But every time I wrote out such a list, it turned out that fact is stranger than fiction,” he said. “I never imagined a species in which males would be a mixture of cells of two lineages, and that one lineage would be used for making sperm. I can only describe this ‘crazy ant sex’ as beyond my imagination.”
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