Anti-insulin protein helps queen ants live five times longer than workers
A fascinating new study has discovered an insulin-suppressing protein that can help extend the lifespan of some ants. The research revealed that in a certain species of ant this anti-aging pathway is activated when workers transition to the position of queen and helps the insects live five times longer.
The new research focused on a particular species of ant called Harpegnathos saltator. Also known as the Indian Jumping Ant, these insects exhibit a relatively unusual behavior. When the queen of a colony dies, the female worker ants battle to take the throne.
And when the winner emerges to become the new queen she undergoes a transition allowing her to start laying eggs. Most curiously, however, alongside this reproductive transition is a dramatic 500% increase in lifespan.
Harpegnathos queens tend to live for between four and five years, while workers barely last longer than seven months. So a team of researchers set out to uncover exactly what changes occur in the ants to trigger such a dramatic lifespan extension.
“By undergoing reversible ‘caste switching’ from workers to pseudoqueens that results in a dramatic increase in both their lifespan and ability to reproduce, Harpegnathos ants provide a unique opportunity to study how aging and reproduction can be disconnected,” said Claude Desplan, co-senior author on the study.
Focusing on the differences in gene expression between the workers and the queen, the researchers quickly discovered the key change that seemed to be occurring was across the insect’s insulin pathways. This finding was expected, as insulin signaling is known to be crucial to egg production.
So, of course the queen’s reproductive pathways are switched on by triggering these insulin processes. But it was a mystery how this mechanism could so dramatically increase the ant’s lifespan.
Here the researchers discovered that when the ant’s ovary production kicks into gear another protein is expressed. Called Imp-L2, the molecule is described as a kind of “anti-insulin” protein. This protein blocks insulin signaling in different pathway found in fat cells and it's this mechanism that is thought to trigger the incredible lifespan-extending feature of the queen.
“The two main branches of the insulin signaling pathway appear to differentially regulate fertility and lifespan, with increased signaling in one aiding reproduction in pseudoqueens and decreased signaling in the other consistent with their extended longevity,” said co-senior author Danny Reinberg.
One of the stranger features of this newly discovered mechanism is its reversibility. These ants can switch from worker to queen and back again, but when they revert back from queen to worker they lose their life-extending benefits, returning to the short seven-month worker lifespan.
While the study is inarguably an intriguing look at a weird life-extending mechanism in a specific type of ant, you are probably asking whether this particular pathway is present in any other organisms. And the answer according to Desplan is, maybe …
The researchers note there are prior studies suggesting Imp-L2 pathways can be found in fruit flies but it’s unclear whether the mechanism has the same life-extending effect. The next step for Desplan and colleagues will be to investigate whether this mechanism can be detected in other invertebrates, and then, maybe, whether a similar pathway can be found in mammals.
The new research was published in Science.