Most species of ants are born into royalty. But for Indian jumping ants, workers can fight for the crown.
Capture? The winner becomes queen, but his brain shrinks as well.
In a study published Wednesday in the Proceedings of the Royal Society B, scientists found that Indian jumping ants can shrink and grow their brains in a few weeks – a fact that has never been seen in insects before and is also incredibly rare in the animal kingdom.
“Indian jumping ants are particularly unique,” said Clint Penick, an assistant professor of biology at Kennesaw State University and one of the study’s authors. “It sheds some of its brain mass to conserve energy and push resources from the brain to the ovaries for reproduction.”
Indian jumping ants, also known as Harpegnathos saltator, are long arthropods known for their forceps-like jaws and large black eyes. And, as their name suggests, these ants can be found in the forests of India, where they hunt and jump a few inches in search of prey.
Like many ant colonies, the nest of an Indian jumping ant contains a queen and thousands of workers who clean royal eggs, hunt food and feed the larvae.
But the similarities stop here.
The lifespan of most ant colonies is often dependent on the lifespan of the queen. When an Indian queen of jumping ants dies, more than half of the colony’s working women participate in a month-long “tour” to fight for a top spot, Penick said. Indian colonies of jumping ants can have many queens.
As hundreds of workers duel, they begin to undergo a physiological change that turns them into queen-type workers called gamergates – “not the online harassment campaign,” he said, referring to a harassment campaign that targeted more many women in the video game industry. in 2014.
A small group of eight to 10 workers will emerge victorious, while the losers will return to their duties as workers, Penick said. The winners will then activate their ovaries to take on the queen’s previous role, “essentially an egg factory,” according to Penick.
During this period, the ovaries of gamergates will increase five times in size, while their brains will shrink by up to 25 percent compared to the anatomy of workers.
“The colony will live and, in essence, in this state, they can theoretically become immortal,” he said.
Penick said the Indian colonies of jumping ants used in the study were the same ones that were collected in India almost 20 years ago and were the first epigenome for the sequenced species.
At one point, he said, he and the other researchers became interested in determining if the brain contraction was reversible and created an experiment to isolate the newly formed gamergates from the colony.
He said he expected to die, but what they found was that Indian jumping ants could regenerate brain size and reduce the size of workers’ ovaries.
“It was incredible,” Penick said. “When we lose brain tissue, we may be able to reproduce some brain cells, but they don’t fully repair and don’t grow back to their original state. It’s gone forever.”
Ants have become a “developmental plasticity model” that can provide details about “which genes control this phenomenon and which parts of the brain retain their ability to grow again,” he said.
Penick added that he believes queens can return to their original form, as losers in the crown duel should be able to return to their responsibilities as workers.
“They need more brain capacity,” he said. “Their main job is to leave the colony, sometimes a few meters away, to find food and bring it back to the nest.”
“He has to remember how to find his way home.”
