A gene mutation turns a group of ants into would-be parasite queens

About a decade ago, scientists observing cloning ants discovered something strange: although this species is known to have no queen, a few ants they posed as queens of the colony, lording over his fellow workers. Are would-be queens They had wings, eyes and giant ovaries.

Researchers had long assumed that these ants Relying on other workers for survival, they acquired these traits one by one, through a series of mutations. But now, scientists discovered that a single “supergene” mutation can convert normal clonal workers from raider ants (Ooceraea biroi) in parasitic queen-like sloths.

“It has been a shocking discovery,” he told live science in an email Waring “Buck” Triple, entomologist, John Harvard Distinguished Science Fellow and lead author of study in which the findings were published. “The clonal raider ant is a queenless ant species, and winged adult females have not been observed in this species before.”

Pseudo queens are born with wings that shed as adults, but retain scars visible. They are the same size as worker ants, but their indifference general to labors such as brood care, foraging, and nest defense make them stand out in the colony.

The researchers isolated the parasites and found that their offspring also had wings, suggesting that queen traits were genetic. They performed analyzes to confirm this observation and discovered a mutation in a “supergene” on chromosome 13.

For them, this mutation it may be the switch that turned clonal raider ants from the “wild type” usually found in nature into a mutant variant of the same species.

“Is really amazinggiven that the parasites differ from the wild ones in many features, such as morphology (segmented thorax), anatomy and even behavior,” he asserted for his part. Daniel Kronauerassociate professor and director of the Laboratory of Social Evolution and Behavior of the Rockefeller University of New York.

What we describe here is a mutant strain that is very closely related to its ancestors wild type. So it’s not really a different species, but what could be considered an intermediate form, Kronauer added.

The researchers observed that would-be queens they laid twice as many eggs than normal cloning ants. However, they cannot let their numbers grow too much, because they need the workers. “When they become too common, they run into problems,” Kronauer said. The parasites hook their bulky wings into the skin of the pupae when they moult, and if there aren’t enough workers around to help untangle them, many of them die.

According to the study, published February 28 in the journal Current Biology, the optimal point seems to be when the parasites make up about a quarter of the colony. When the proportion of would-be queens was higher, their survival rates they plummeted.

Although some species of exclusively social parasitic ant queens exist in nature, the cloning ant is the first documented to have developed aspirants within its own species. “I was very surprised to find these ants,” Kronauer said.

And he concluded: “The social parasites they tend to be very rare and are only found in a few colonies of the host species. But what is crazy in this case is that the parasites must have arisen within the host colony through mutation, instead of having infiltrated the colony from outside, as social parasites do in nature.”

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