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A tapeworm fundamentally changes the lives of ants: Workers of the species Temnothorax nylanderi infected with the tapeworm Anomotaenia brevis live several times longer than their uninfected nestmates. They are also less active, and their metabolism becomes more similar in some respects to that of queens. A new study by Johannes Gutenberg University Mainz (JGU), published in the journal BMC Genomics, reveals the molecular basis of this unusual effect.
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The researchers found evidence that the parasite alters existing biological programs in the ant. For the tapeworm, this change could be advantageous because the ants serve as intermediate hosts. The parasite develops fully only in woodpeckers, its definitive hosts. The fact that infected workers live longer and are less active could promote its transmission.
For the study, the team led by Professor Susanne Foitzik from the Institute of Organismic and Molecular Evolution (iomE) at JGU examined ants from the Lenneberg Forest near Mainz. In the laboratory, the ants were assigned to three groups: queens, workers infected with the tapeworm and uninfected workers.
The researchers dissected the brain and fat body from the ants. The fat body is tissue in the abdomen that is important, among other things, for metabolism and the immune system. They then used RNA sequencing to analyze which genes were active in the brains and fat bodies. In addition, they examined genome and transcriptome data from the tapeworm—data on its genetic material and active genes. This allowed them to test whether the parasite mimics the ants' own signaling molecules.
Infection alters ant physiology in a targeted way
"Our genetic analyses show that the infection does not simply make the ants sick, but alters their physiology in a highly targeted way," said Foitzik. "At the molecular level, infected workers showed a profile that was partially queen-like." This was particularly clear in the fat body. "There, we found clear overlaps between infected workers and queens." The affected genes included those linked to metabolism, the immune system, stress resistance and aging processes.
"The findings in the fat body suggest that the tapeworm taps into and shifts existing signaling and metabolic pathways in the ant," said Foitzik. This finding is particularly interesting for the aging of the animals: Earlier studies of this ant–tapeworm system have shown that infected workers have survival rates approaching those of queens. Queens of this species can live up to 20 years, while workers usually live only one to two years. The fact that infected workers show a partly queen-like molecular profile in the fat body could help explain this effect.
Dampened signals in the brain
The picture was different in the brain. There, infected workers were much less similar to queens. Instead, many neuropeptides—signaling molecules that can influence behavior, feeding and social responses—and their receptors were downregulated. The altered activity of these signaling pathways could help explain why infected workers show less worker-like behavior.
"The effect of the infection is therefore tissue-specific," explained Giulia 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 the brain, by contrast, many signaling pathways linked to behavior and activity are dampened."
One possible explanation would have been that the tapeworm mimics ant signaling molecules by producing its own neuropeptides that resemble those of the ants and thus trick the ants' signaling system. However, the researchers found no evidence for this because the peptides produced by the parasite were not sufficiently similar to those of its host.
"The data rather suggest that the parasite influences the ant indirectly by intervening in the host's own regulatory networks, which control metabolism, the immune system, aging and behavior, among other processes," said Blasi.
Model for parasitic manipulation
"Queens and workers of social insects share the same genetic basis, but differ greatly in lifestyle and lifespan," said Foitzik. "The fact that infected workers show a partly queen-like molecular profile in the fat body suggests that the parasite taps into existing biological programs of the ant." The ant-tapeworm system therefore provides a suitable model for investigating how parasites can alter the aging and behavior of their hosts.
More information: Giulia Blasi et al, Cestode infection is linked to transcriptional shifts in neuropeptide signalling and caste-specific ageing pathways in a social insect, BMC Genomics (2026). DOI: 10.1186/s12864-026-12959-6
Provided by Johannes Gutenberg University Mainz
This story was originally published on Phys.org.
