Image source: Susanne Foitzik: A Temnothorax nylanderi worker ant infected with the tapeworm Anomotaenia brevis, recognizable by its yellowish color, next to an uninfected worker ant.
Deep in the damp foliage of the Lenneberg Forest near Mainz, Germany, tiny worker ants of the species Temnothorax nylanderi live surprisingly long lives. While ordinary worker ants typically live short, busy lives of only one to two years, a worker carrying a parasitic tapeworm called Anomoteenia brevis can live several times longer.
Instead of dying young, their chances of survival begin to match those of their queen, a royal ant that can live for up to twenty years.Now, a detailed study published in the journal BMC Genomics shows how this unusually long life actually works. Scientists at Johannes Gutenberg University Mainz (JGU) have found that the tapeworm doesn’t just make the ant sick or weak. Instead, it carefully alters how the ant’s genes work, modifying the body’s natural processes so that the worker’s physical body begins to behave more like that of a long-lived queen ant.
Benefit from proprietary biology
To understand how the parasite’s lifespan is extended, an international research team led by Professor Susan Wojcik from the Institute for Organismal and Molecular Evolution (iomE) at JGU brought forest ant colonies into the laboratory. They divided the ants into three test groups: healthy queens, healthy, uninfected workers, and workers carrying the tapeworm parasite.Scientists carefully removed two main parts of the ants: the brain and the fat body.
In insects, the fat body is an important abdominal tissue that stores energy, manages digestion, deals with stress, protects the immune system, and functions much like the human liver. Using advanced RNA sequencing, the researchers measured which genes were active in these tissues. They also examined genetic data from the tapeworm itself to track its activity and check whether it was using deceptive chemical tricks.The results showed a clear difference in how the parasite affects its host.
Instead of causing general damage, the infection changed the ants’ active genes in a very specific way.“Our genetic analyzes show that infection not only makes ants sick, but changes their physiology in a very targeted way,” said Susan Wojcik. “At the molecular level, affected workers showed a partial queen-like appearance.”This transformation was strongest within the fat body. The genes active in affected workers closely match those in long-lived queens, especially the biological systems responsible for digestion, immune protection, stress resistance, and aging.“The findings in the fat body suggest that the tapeworm exploits existing signals and metabolic pathways of ants and alters them,” Wojcik said.
Quiet brains and slow behavior
While the parasite changes the ant’s body to slow aging, it takes a completely different path inside the brain. In healthy nests, worker ants build and collect food, care for young ants and protect the colony. However, infected workers become very quiet, do much less work and remain immobile inside the nest for long periods.When the researchers examined the brain tissue, they found that the affected workers did not resemble the queens at all. Instead, many neuropeptides, chemicals that control social behavior, feeding, and energy levels, along with the parts of the cell that receive them, were reduced.“The effect of infection is tissue specific,” explained Julia Blasi, first author of the study and a doctoral researcher at iomE.
“In the fat body, we see a shift toward a queen-like metabolic profile. In contrast, many signaling pathways associated with behavior and activity are attenuated.”
Indirect acquisition strategy
At first, scientists wondered whether the tapeworm made its own mimic chemicals to directly trick the ant’s brain and body. Many parasites produce fake chemicals that resemble their host’s own signals, tricking the host’s body into doing what the parasite wants.However, genetic tests on the tapeworm showed that its chemicals were not similar enough to those in the ant to act as direct copies.“The data suggest that the parasite affects the ant indirectly by interfering with the host’s regulatory networks, which control metabolism, the immune system, aging, and behavior, among other processes,” Blasi said.This clever method fits the tapeworm’s life plan. For Anomoteenia brevis, the worker ant is just a temporary home.
The parasite cannot lay eggs inside the ant; Its full life cycle can only end inside the stomach of the woodpecker, its primary host.Keeping the host ant alive longer while making it slow and lazy serves a real purpose. An ant that lives for years inside the nest without burning itself gives the tapeworm a safe and stable home. Meanwhile, the slow and relaxed ant easily prepares food when the woodpecker opens the nest in search of a snack.
A clear view of how aging works
The research, funded by the German Research Foundation, was conducted by JGU researchers Susanne Wojcik, Julia Blasi and Katarina Schwolow, along with Hugo Darras from Zhejiang University in Hangzhou, China.The findings give scientists a useful natural setting to study how aging is controlled at the genetic level. Because worker ants and queen ants are born from exactly the same genetic instructions, their very different lifespans depend entirely on which genes are turned on or off.“Queens and workers of social insects share the same genetic basis, but differ greatly in lifestyle and life span,” said Susan Wojcik. “The fact that infected workers exhibit a partial queen-like molecular profile in the fat body suggests that the parasite exploits the ants’ existing biological programs.”The study was conducted by Julia Blasi, Katharina Schwolow, Hugo Daras, and Susanne Wojciech of Johannes Gutenberg University Mainz. Their research is entitled Cestode infection is associated with transcriptional shifts in neuropeptide signaling and social class-specific aging pathways in the social insect. Investigates how parasitic infections affect gene activity and aging pathways in social insects.