Parasites make wolves more likely to be pack leaders.chemistry

toxoplasma gondii is sometimes called a “mind control” parasite. It can infect the animal’s brain and disrupt the animal’s behavior in a way that can potentially kill the host, but it helps ensure the spread of the parasite.But now researchers have discovered that infected wolves may actually benefit from these mind-altering tricks. toxoplasma They found that the infection made wolves more daring and more likely to become pack leaders or disperse to other habitats, increasing their chances of breeding.

“We’ve really underestimated some of the consequences of this parasite,” says Eben Gering, a biologist at Nova Southeastern University who was not involved in the study. of wild ecosystems. ”

T. Gondiis a single-celled parasite that reproduces only in domestic cats and other felines. Infected cats excrete spore-filled oocysts in their faeces. Oocysts can survive in plants, soil and water. They can also persist in undercooked livestock and game. When the host (including humans) consumes the oocysts, the spores are released and spread to the brain and muscles to form new cysts. Worldwide, about 1 in 4 people are infected with her. The immune system normally keeps the parasite in check, but it can cause spontaneous abortions and other serious problems during pregnancy.

It has long been known to infect rodents toxoplasma lose fear of predators. Cysts in the brain somehow increase dopamine and testosterone, increasing boldness and risk-taking, and increasing the likelihood that the host will be eaten by cats. “It uses mind control or personality control,” says Jaap de Roode, a biologist at Emory University who was not involved in the new research. It can lead to all sorts of interesting results.”

Results are not limited to rodents. In 2016, Gabon researchers found that: toxoplasmaInfected captive chimpanzees lost their aversion to leopard urine.And last year another team explained how toxoplasma– infected Kenyan hyena cub Closer to lions and more likely to be killed.

When researchers learned a few years ago that some wolves in Yellowstone National Park were infected toxoplasmaConor Meyer, Ph.D., a student at the University of Montana, teamed up with park biologist Kira Cassidy to find out if parasites alter the behavior of wolves.

Meyer and Cassidy delved into 26 years of research on gray wolves in the park. toxoplasma Test results from blood samples taken in various park areas. They also looked at data on cougars. toxoplasma It can be reproduced.Wolves exposed to areas with high cougar populations are now more likely to be infected toxoplasma, they found. The authors say these wolves likely got infected from cougars.

Combining infection data with historical field observations, they also found that they were infected Wolves were much more likely to be pack leadersthe team reports today communication biologyInfected wolves were also more likely to leave the herd at a young age to seek out new territory and other herds, just as infected rodents became more eager to explore. There may be some cases where wolves and packs really succeed because they are pushing boundaries and becoming more risk-taking,” says Cassidy.

This study is one of the few to investigate toxoplasma in the wild. “We know that infection can change animal behavior, but it’s very difficult to document it in wildlife populations,” says Megan, a wildlife disease ecologist at the University of Minnesota. Kraft said. “The great thing about this study is that we are able to take advantage of the wonderful long-term studies to unlock these nuanced effects of infection and behavior.”

As with rodents, the audacity of wolves also carries risks. Wolves that roam widely are more likely to be run over by cars or leave park boundaries. shot by a hunter“Dispersal is one of the most dangerous things wolves can do,” says Meyer. An infected herd leader can also transmit the parasite during mating, jeopardizing pregnancy as in dogs. Ultimately, Cassidy thinks the risk of infection probably outweighs the benefits in the long run. “Wolves live on the knife edge of survival to begin with,” says Cassidy.

because the wolf One of the park’s keystone species“They can control the food web. They control the flow of energy within the ecosystem,” de Roode says. I can do it.”

Infected pack leaders can also affect uninfected wolves, the researchers speculate in the paper. Herd members mimic the leader’s boldness or curiosity about the cougar’s scent, and more wolves may become infected. “It’s a great idea and I think it has a lot of potential,” he says Gering.

Ultimately, wolves appear to be dead-end hosts toxoplasmaHowever, because it is unlikely that you will transfer the parasite back to the cougar. Yet Meyer wonders whether the parasite’s effects on wolves mean that the animals were involved in an infectious cycle at some point in the distant past. It roamed North America and may have preyed on these infected (and emboldened) beasts.