A worker ant of the species Temnothorx nylanderi infected with the tapeworm Anomotaenia brevis, recognizable by its yellowish coloration, alongside an uninfected worker
Photo Credit: ©: Susanne Foitzik
Scientific Frontline: Extended "At a Glance" Summary: Parasitic Life Extension in Ants
The Core Concept: Infection by the tapeworm Anomotaenia brevis fundamentally alters the physiology of Temnothorax nylanderi worker ants, significantly extending their lifespan while suppressing their natural activity levels.
Key Distinction/Mechanism: Rather than producing its own mimic signaling molecules, the parasite indirectly taps into the host's existing biological programs. It triggers a queen-like metabolic and aging profile in the ant's fat body while downregulating behavioral neuropeptides in the brain.
Major Frameworks/Components:
- Transcriptomic Analysis: The use of RNA sequencing to analyze gene expression independently in the ant's brain and fat body.
- Tissue-Specific Reprogramming: The upregulation of genes linked to metabolism, immune response, stress resistance, and aging in the fat body, mirroring the biology of long-lived queen ants.
- Neurological Suppression: The downregulation of neuropeptides and receptors in the brain, reducing typical worker behavior to facilitate transmission to the tapeworm's definitive host, the woodpecker.
- Indirect Manipulation: The parasite alters the host's innate regulatory networks rather than utilizing direct chemical mimicry to hijack biological systems.
Branch of Science: Entomology, Parasitology, Evolutionary Biology, Genomics, and Molecular Biology.
Future Application: The T. nylanderi and A. brevis system provides a functional genetic model for investigating how parasites manipulate host aging, metabolism, and behavior at the molecular level.
Why It Matters: Understanding how parasites hijack host longevity and behavioral pathways offers critical insights into the molecular mechanisms of aging and the broader evolutionary dynamics of parasitic manipulation.
A tapeworm fundamentally changes the lives of ants: workers of the species Temnothorax nylanderi that are infected with the tapeworm Anomotaenia brevis live several times longer than their uninfected nestmates. They are also less active, and their metabolism becomes partially similar to that of queens. A new study by Johannes Gutenberg University Mainz (JGU), recently published in the journal BMC Genomics, reveals the molecular basis of this unusual effect.
The researchers found evidence that the parasite alters existing biological programs in the ant. For the tapeworm, this change could be advantageous, as 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, these ants were assigned to three groups: queens, workers infected with the tapeworm, and uninfected workers. From the ants, the researchers dissected the brain and the fat body, a tissue in the abdomen that is important for metabolism, the immune system, and other functions. 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, meaning data on its genetic material and the genes active within it. 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 Susanne Foitzik. "At the molecular level, infected workers showed a profile that was partially queen-like." This was particularly evident 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 existing signaling and metabolic pathways of the ant and shifts them," said Foitzik. This finding is particularly interesting regarding the aging of the insects: 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 for up to twenty years, while workers usually live for only one to two years. The fact that infected workers show a partially 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—as well as their receptors, were downregulated. The altered activity of these signaling pathways could help explain why infected workers exhibit 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, thus tricking the ants' signaling system. However, the researchers found no evidence for this, as 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 Susanne Foitzik. "The fact that infected workers show a partially 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.
Funding: The study was funded by the German Research Foundation. Susanne Foitzik, Giulia Blasi, and Katharina Schwolow from JGU, as well as Hugo Darras from Zhejiang University in Hangzhou, China, were involved in the project.
Published in journal: BMC Genomics
Authors: Giulia Blasi, Katharina Schwolow, Hugo Darras, and Susanne Foitzik
Source/Credit: Johannes Gutenberg University Mainz
Edited by: Scientific Frontline
Reference Number: ent072126_01
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