For some ant queens, the secret to long life may be a self-produced insulin blocker.
Queen ants are famous for their longevity, even though they shouldn’t be. Generally, animals that devote a lot of energy to reproduction sacrifice some time of their lives. But queen ants produce millions of eggs and live an extraordinarily long time compared to worker ants that don’t reproduce.
Now researchers have shown how one species of ant achieves this anti-aging feat. When queens and would-be queens of the species Harpegnathos Leaper prepare to reproduce, a part of what is called the insulin signaling pathway it crashesdelaying aging, researchers report in the Sept. 2 issue Sciences. That molecular pathway has long been implicated in the aging of mammals, including humans.
“There has been a need to understand why queens, or reproductives, in social insects can live for so long,” says Marc Tatar, a biologist at Brown University in Providence, Rhode Island, who was not involved in the study. Some species of ants have queens that survive 30 times longer than their workers. Other social insects like bees and termites also have long-lived queens.
In rare behavior for ants, when a queen H. jumper dies, some workers begin to compete in duels for the opportunity to replace it (Serial number: 01/17/14). These hopeful royals develop ovaries, start laying eggs, and transition into queen-like forms called gamergates. When a worker transitions to a gamergate, his lifespan becomes five times longer than it was. But if she doesn’t end up becoming queen and go back to being a worker, her life is shortened again.
The researchers exploited this behavior to investigate the molecular underpinnings of antiaging in these ants. H. jumper It turns out that gamergates extend their lifespan by taking advantage of a split in the insulin signaling pathway, the chain of chemical reactions that drive insulin’s effects in the body. One branch of this pathway is related to reproduction, while the other is involved in aging.
“Insulin comes with our life — [after] we eat, we have a lot of insulin,” says Hua Yan, a biologist at the University of Florida in Gainesville. “But a consistently high level of insulin is bad for longevity.”
By examining gene activity patterns, Yan and colleagues found that gamergates have more active insulin genes than regular worker ants and, as a result, have higher metabolic activity and ovary development. But the secret ingredient that protects the ants from the aging effects of insulin appears to be a molecule called Imp-L2, which blocks the branch of the insulin pathway linked to aging, experiments showed. The branch involved in reproduction, however, remains active.
“What we don’t understand is how Imp-L2 can act on one aspect of the pathway and not the other,” says study co-author Claude Desplan, a developmental biologist at New York University.
These results represent a leap forward in our understanding of the extreme longevity of social insects, the researchers say, while also showing an evolutionary anti-aging adaptation that had not been seen before in nature.