Increases the chance of a parasitic wolf becoming a pack leader | Science

Toxoplasma gondii It’s sometimes called a “mind control” parasite: It infects an animal’s brain, messes up their behavior, and can kill the host, but helps ensure the parasite’s spread. But now researchers have found that infected wolves can benefit from these mind-altering tricks. A Toxoplasma The infection makes wolves bolder and more likely to become pack leaders or spread to other habitats to breed.

“We underestimated some of the consequences of this parasite,” said Eben Gehring, a biologist at Nova Southeastern University who was not involved in the work. “The findings may represent the tip of the iceberg regarding the importance of parasite dynamics in wild ecosystems.”

T. gondii, a single-celled parasite that reproduces only in domestic cats and other felines. Infected cats excrete spore-filled eggs in their feces, which live on plants, soil, and water. They can also remain in undercooked meat from livestock or game. When a host (including humans) eats the egg cells, the spores spread to the brain and muscles, forming new cysts. Worldwide, one in four people are infected. Usually the immune system keeps the parasite under control, but it can cause spontaneous abortions and other serious problems during pregnancy.

Rodents have long been known to be infected Toxoplasma lose their fear of predators. A cyst in the brain somehow increases dopamine and testosterone, increases courage and risk-taking, and increases the likelihood that a pet will be eaten by a cat. “These parasites use general mental control or individual control to help them complete their life cycle,” said Emory University biologist Jaap de Roode, who was not involved in the new study. “And it has all kinds of interesting consequences that we haven’t even thought about before.”

The implications are not limited to rodents. In 2016, researchers in Gabon discovered this Toxoplasma-infected captive chimpanzees became averse to leopard urine. Last year, another team explained how Toxoplasma– infected Hyena cubs in Kenya get close to the lions and increase your chances of killing them.

A few years ago, researchers discovered that some wolves in Yellowstone National Park were infected Toxoplasma, Connor Meyer, Ph.D. student at the University of Montana worked with park biologist Kira Cassidy to study whether the parasite changes wolf behavior.

Meyer and Cassidy have been researching gray wolves in the park for 26 years. Toxoplasma test results from blood samples collected from different areas of the park. They also studied data on cougars Toxoplasma reproducible. Wolves scattered in areas with high numbers of cougars were more likely to be infected Toxoplasma, they found. According to the authors, these wolves may have been infected by eating the meat of big cats or from pugs.

By combining infection data and past field observations, they discovered that they were infected was more likely to become the leader of the wolf packthe team informed today Biology of communication. Infected wolves were also more likely to leave packs at a young age and seek new territories or other packs, so infected rodents were more likely to explore. “There may be a few cases where wolves, and even their packs, actually succeed because they’re crossing those boundaries and are more at risk,” Cassidy said.

This study is one of very few Toxoplasma In nature. “We know that infection can change animal behavior, but it’s very difficult to document that in wild animal populations,” said Meggan Craft, a wildlife disease ecologist at the University of Minnesota. “What’s great about this study is that it leverages an impressive long-term study that can tease apart these subtle effects of infection and behavior.”

As with rodents, bravery comes with risks for wolves. Wolves that roam in large numbers are more likely to be hit by cars or leave park boundaries. shot by hunters. “Dispersal is one of the most dangerous things a wolf can do,” Mayer said. An infected pack leader can also transmit the parasite during mating and endanger pregnancy, as is the case with dogs. On balance, Cassidy suspects the risk of infection may outweigh the long-term benefits. “For starters, wolves live on a knife’s edge,” Cassidy said.

Because the wolf one of the main stone species of the parkThe parasite “can have a really significant effect on the ecosystem,” de Rood said. “They can control the food chain; They can control the flow of energy within the ecosystem.”

Infected pack leaders can even affect uninfected wolves, the researchers hypothesize in their paper. Pack members can imitate the boldness of their leader or the smell of rockets out of curiosity and can infect many wolves. “It’s a great idea, and I think it’s very likely,” Gehring said.

After all, wolves appear as masters of dead ends Toxoplasma, but since they are unlikely to return the parasite to the cougars. However, Meyer wonders if the parasite’s effect on wolves means the animals played a role in the infection cycle in the past. He noted that large lions roamed North America during the last ice age, possibly hunting these infected and emboldened beasts.

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