Parasitic tapeworm helps worker ants live like a 'queen' before dying in pain

Parasites often cause trouble for the host, but the tapeworm Anomotaenia brevis infesting ants keeps the host young and healthy.

Researchers from Johannes Gutenberg University in Mainz, Germany observed 58 colonies of Temnothorax nylanderi ants over three years. They found that some of the ants were infected with the tapeworm Anomotaenia brevis , some were not. With a few infected Temnothorax nylanderi, scientists found up to 70 tapeworms inside.

At the end of the trial, all uninfected workers died. Meanwhile, half of the infected worker ants are still alive.

An ant Temnothorax nylanderi. (Photo: WM)

Tapeworms will prompt the host to develop pheromones that cause uninfected ants to brush, feed, and even carry them around. Ants are initially yellow, then gradually turn brown as they age and the skin hardens. However, infected ants still retain their yellow color.

These worms manipulate the lifespan of the Temnothorax worker ants by secreting chemicals that control the endocrine, immune systems and even the genes of the host. It turned on genes that were present in the queen Temnothorax, but were turned off in the worker ants. This helps Temnothorax infected workers live longer.

According to the study, infected Temnothorax ants live at least three times longer than their counterparts. Some live up to 20 years old, equivalent to the lifespan of a queen ant.

Temnothorax worker ants don't have to do anything to eat.

Not only that, hormonal changes also cause tapeworm-infected worker ants to secrete a scent similar to the queen ant. This causes other ants in the nest to begin to mistakenly think they are serving a queen. The other worker ants keep bringing food back to the nest and leave it around the Temnothorax worker ants infected with tapeworms. Temnothorax worker ants so they don't have to eat anything.

Sometimes, they are so lazy that other worker ants have to gather to carry the infected Temnothorax like a palanquin. They are cared for and groomed more than true queens in the nest, a phenomenon unheard of in a typical insect society.

But Anomotaenia brevis has sinister reasons for keeping its hosts healthy and slow. It makes the ants perfect prey for any woodpeckers that come near the nest to feed.

While the healthy ants ran to another place to escape, the infected ants just sat there and were quickly slaughtered.

When the woodpecker eats the infected ant, the tapeworm will reproduce inside the woodpecker's stomach, their eggs will be excreted in the feces.

At this point, the ants will feed their young with this excrement, helping the tapeworm to start a new life cycle.