If the horror fiction short The Monkey's Paw where a couple wishes to have their son alive again has taught us anything, it's that life and death are perched on a delicate balance, and an imbalance, be it supernatural or natural, always comes with a great price.
Scientists have discovered that the workers of the ant species Temnothorax nylanderi live much longer than their uninfected nestmates and stay younger when they are infected with a tapeworm called Anomotaenia brevis, which live in the ants’ guts. However, this unusual relationship has a pretty dark downside.
The observations were done on 58 colonies
The long-term scientific study, published in the journal Royal Society Open Science, had a team of researchers from Johannes Gutenberg University Mainz observing 58 colonies of Temnothorax nylanderi ants -- some infected, some not -- for three years. These ants are common in Central Europe where they serve as an intermediate host for the tapeworm, which can attack a single ant with up to 70 parasitic larvae, according to a press release.
Over the course of three years, all of the original uninfected worker ants died, while 53 percent of the infected ants continued to thrive. Normally in this species, queens can live up to 20 years, while workers rarely reach the age of two. This is incredibly interesting since it's not common that a parasite, which usually spells trouble for its host, can trigger such a positive change, extending its lifespan dramatically.
Furthermore, despite their old age, the infected ants maintained their youthful appearance and had similar metabolic rates and fat proportions as young animals. The researchers stated this "eternal youth" phenomena could be explained by the tapeworm larvae releasing proteins with antioxidants into the ants' hemolymph and changing the activity of ant genes that influence aging.
The infected ants were also less active. They gave off chemical signals that urged their nestmates to look after them, so they were looked after by other workers in the nest, receiving more attention, being fed, cleaned, and even carried around.
Uninfected ants suffered
However, this spelled trouble for the uninfected ants, New Atlas reports. Not only the uninfected ants appeared to be more stressed, but they also died earlier than they could have if the parasites weren't in the picture.
You may be wondering what's in it for the parasites. Well, their ultimate goal is to complete their very complex life cycle, in which they reproduce within the gut of a woodpecker that has an appetite for ants. A lazy ant that waits to be eaten by a woodpecker is the perfect ally the parasite needs in this case. Once the parasite leaves the woodpecker's body and an ant stumbles upon it, the cycle begins again.
The researchers say further investigation at the molecular and epigenetic level is needed to really understand what is going on, but what we know so far provides a unique look into the world of these little creatures. According to a 2018 research, though, ants are not the only species that hosting a parasite brings unexpected side effects, such as feeling high.