Introducing the brain: some ant brains shrink and grow (Introduction)

by David Turell , Thursday, April 22, 2021, 16:21 (1380 days ago) @ David Turell

Indian jumping ants were studied:

https://www.npr.org/2021/04/18/988262580/the-incredible-shrinking-and-growing-brains-of...

"'In most ants, the queen is the only member of the colony that lays eggs," says Clint Penick, an assistant professor of biology at Kennesaw State University in Georgia. "The workers just do all of the hunting and take care of the babies and all of the chores in the colony. But the queen is the only one who reproduces. And when she dies, the colony dies."

"Not so for this type of ant, native to India. Their worker ants have the ability to mate and reproduce. So when the Indian jumping ant queen dies, "it actually triggers a dominance tournament. And they'll fight each other over a month to decide who's going to be the next ant to replace the queen."

"(These are all females we're talking about. The males really aren't involved in anything here except mating and dying.)

"The queen doesn't have an exact replacement. A handful of tournament winners — called "gamergates" — all assume queen-like duties of laying eggs.

"Penick and his colleagues found that when the ants take on the role of gamergate, their brains shrink by 19% on average. The shrinkage likely happens so that they can save energy to focus on producing eggs. Hormones trigger additional changes in the ants, including larger ovaries, less venom production and much longer lifespans.

"The fact that the ants' brains shrink to reproduce wasn't new.

"'But what we didn't know was if they had the capacity to regrow them back to their previous size," Penick tells NPR's Lulu Garcia-Navarro

***

"Penick and other scientists plucked these gamergates away from their colonies for a few weeks. The thinking was that the lack of social interaction and care would make them revert back to their previous worker status.

"It worked. After several weeks, the ex-gamergates were back to being lowly workers — with their bigger brains regrown.

***

"'It tells us that brains are a lot more plastic and have a lot more abilities to change back and forth between their size than we knew," Penick says. "And ants, their brains have some shared traits with humans, believe it or not. So now we're looking at digging into some of the genetic and other neural mechanisms that are underlying these brain changes.'"

Comment: Some branches in evolution have strange results, but this is a logical result as a tradeoff. Brains take lots daily energy requirements (20% in humans), and egg production is very energy demanding. It doesn't mean any other species brain can learn to do it.