The parasites infect these beetles. It could be a good thing.

Leishmaniasis parasites eat human flesh. Cordyceps mushrooms lead ants to suicide. Toxoplasma gondii eliminates fear of cats in mice. And a barnacle called Sacculina carcini castrates crabs, is rooted in their bodies and brains and turns them into traveling zombie slaves who care for the brood of the parasite as if it were theirs.

Parasites are bad – except when they are not.

In the forests of eastern North America, wood-eating beetles chew fallen logs. This helps to break down the wood and restore the nutrients to the soil. But many beetles are infected by the thousands with a parasitic common worm that gives their interior the appearance of a spaghetti plate in motion.

There is little evidence that parasites are harmful. Instead, infected beetles appear to be fatter and eat more than uninfected ones, suggests a study published Wednesday in Biology Letters. This increased consumption can help nutrients in the forest cycle more quickly and benefit the entire ecosystem.

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"Everything is connected," said Andy Davis, an ecologist at the University of Georgia, who led the research. "Here is a case where there is a small insect in the forest and offers a service in the forest. It's doing something important. But then there is another bug that lives in this bug that is doing something important. "

the The horned colus, also called a big-hip beetle, is about the size of your thumb and weighs as much as two raisins. It is one of the rare insects to live with his family and he communicates by emitting a dozen different sounds.

A curved horn protrudes above its monstrous mandibles, with which it eats decaying logs from within. He prefers hard woods – oak or elm – that he chews and excretes in the form of sawdust so that microbes can further decompose it. The beetle then repeats this matterI'm spitting for his youngsters. About 70 to 90% of the Bess beetles also occupy Chondronema passali, a parasitic nematode that drains its energy.

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Dr. Davis noted that parasitized beetles encountered difficulties in tasks requiring large bursts of energy, such as fighting other beetles, closing wounds or escaping predators. But they did not seem embarrassed in their daily activities and did not lose as much weight as uninfected insects stressed, even with a belly full of worms. This led Dr. Davis to think, "Maybe they somehow offset the energy absorbed by parasites by eating more."

To find out, he and Cody Prouty, a student from his lab and co-author, collected more than 100 beetles in the forest and housed them in old ice cream containers with a piece of wet wood for nibbling. After three months, they determined how much the beetles had eaten by weighing the sawdust left behind. They weighed and measured the beetles and then dissected them for nematodes.