Behavior-changing parasite moves wolves to the head of the pack - Ars Technica

Leadership grooming —

A parasite associated with bold behaviour is besides associated with battalion leadership.

Diana Gitig - Nov 29, 2022 6:14 p.m. UTC

Toxoplasma gondii is a ubiquitous protozoan parasite that tin infect immoderate warm-blooded species. In laboratory studies, infection with T. gondii has been shown to summation dopamine and testosterone levels on with risk-taking behaviors successful hosts including rodents, chimps, and hyenas. Oh, and humans.

But its effects person not truly been studied successful the wild, truthful immoderate researchers decided to measure however corruption impacts grey wolves successful Yellowstone National Park. They recovered that “the likelihood that a seropositive [infected] wolf becomes a battalion person is much than 46 times higher than a seronegative wolf becoming a battalion leader.”

In the wild

Serum samples person been taken from the wolf packs successful Yellowstone since 1995. These scientists assayed samples from 229 idiosyncratic wolves taken implicit the years—116 males, 112 females, and 1 hermaphrodite—to effort to correlate the beingness of antibodies against the parasite with demographic factors and circumstantial behaviors. (The narration betwixt antibodies and corruption is complicated, fixed that the parasite tin persist astatine debased levels indefinitely aft infections.)

Gray wolves and cougars are intermediate hosts and definitive hosts, respectively, of T. gondii, meaning the parasite grows to intersexual maturity successful wolves but needs to infect cougars to reproduce sexually. The 2 carnivores person immoderate overlapping territory wrong Yellowstone, particularly on its bluish edge, and they vie for the aforesaid prey. Living successful an country of precocious cougar overlap was the azygous biggest predictor of a wolf being infected with the parasite, much than immoderate demographic factors similar the wolf’s age, sex, oregon overgarment color.

Wolves with antibodies against the parasite were importantly much apt to disperse (leave their packs and acceptable retired connected their own) and to go battalion leaders. Pursuing some of these courses of enactment constitutes assertive and risky wolf behavior, and they correspond the 2 biggest decisions successful a wolf’s life.

Parasites successful charge?

Because grey wolves unrecorded unneurotic successful groups, battalion leaders person a disproportionate effect connected their corporate decisions. An infected person whitethorn summation the wide fig of infected wolves, some due to the fact that battalion leaders person a reproductive vantage and due to the fact that risk-taking leaders mightiness beryllium little hesitant to pb their packs into cougar territory, wherever they tin prime up their ain infections.

Plus, wolves are societal creatures who larn from and emulate their leader’s behaviors. So T. gondii-infected, aggressive, risk-taking battalion leaders tin output “a much assertive, risk-embracing battalion civilization adjacent though lone a fewer cardinal individuals are really infected.”

Of course, accrued engagement successful risky behaviors is dangerous, truthful immoderate of these hyper-aggressive wolf leaders and the packs that transcript them are much apt to get themselves killed. Regardless, the selfish genes dictating their behaviors and their fates aren’t adjacent their ain genes. Parasites are the puppeteers.

communications biology, 2022. DOI: 10.1038/s42003-022-04122-0