Deep in the German forest, ants have stumbled upon a fountain of youth in the form of a parasite. Researchers discovered that this parasite is responsible for drastically extending the lifespan of worker ants, but at a terrible cost.
Parasites are bad news for the host; besides competing for nutrients or other resources, they can spread diseases, which can be fatal. However, at first glance, that didn’t seem to be the case for the relationship between Anomotaenia brevis tapeworms and Temnothorax nylanderi ants. The devious parasites live in the ants’ guts, where they grant their hosts much longer lifespans than uninfected ants.
The Study
Researchers at Johannes Gutenberg University Mainz analyzed fifty-eight ant colonies for three years, some infected with the parasites and some parasite-free. After three years, about 53% of the original, infected insects were still alive, but none of the uninfected worker ants survived.
The infected ants’ maximum lifespan is unknown due to the study’s length. However, the trend suggests they are on par with queens, which can live for up to 20 years. The researchers published the study in Royal Society Open Science.
More Popular Than The Queen
The infected ants retained their youthful bodies at their older age. Uninfected young ants started a yellowish color and then turned brown with tougher skin as they aged, while infected ants remained yellow.
What’s more, infected ants became lazy and never left the nest or chipped in to help with any of the usual chores. Instead, they lounged around the nest while their uninfected colony-mates groomed them, fed them, and even carried them around. Sometimes, they were more popular than the queen herself!
Consequences And End Game
While it seems like a good life for the individual infected ants, the colonies as a whole began to suffer the consequence of their laziness. Uninfected ants were more stressed, and we’re dying younger than they might have if the parasites never existed.
So, what’s in it for the parasite? The researchers found that the tapeworms are playing the long game by keeping infected ants pampered and lazy. Soon enough, a woodpecker will come pecking on the nest, and uninfected ants will quickly scatter away while the infected ones stay relaxing and end up getting eaten.
These worms then reproduce inside the woodpecker’s gut. The bird eventually poops out the tapeworm eggs, where ants will find them and bring them back to their nest to feed them to their young, starting the cycle all over again.
Life-Boosting Genes
The researchers also found metabolic changes in infected ants that drive this biology and behavior. When healthy worker ants are “promoted” to queens, life-boosting genes switch on. The worms seem to be able to turn on these same genes in their hosts.
Additionally, infected ants emit unique chemical signals that encourage their nest-mates to want to pamper them.
