Parasitic infection increases risk-taking in a social, intermediate host carnivore

Area of Science:

• Ecology
• Parasitology
• Behavioral Biology

Background:

• Toxoplasma gondii (T. gondii) is a widespread protozoan parasite affecting warm-blooded species.
• Infection can alter host behavior, but effects on wild intermediate hosts are poorly understood.
• Yellowstone National Park hosts gray wolves (intermediate hosts) and cougars (definitive hosts) of T. gondii.

Purpose of the Study:

• To investigate the relationship between T. gondii infection and behavior in wild gray wolves.
• To identify predictors of T. gondii infection in wolves within their natural environment.
• To explore the potential ecological implications of parasite-induced behavioral changes in a social carnivore.

Main Methods:

• Utilized 26 years of wolf behavioral, spatial, and serological data from Yellowstone National Park.
• Analyzed wolf territory overlap with cougar density as a predictor of T. gondii infection.
• Correlated T. gondii seropositivity with specific high-risk behaviors like dispersal and pack leadership.

Main Results:

• Wolf territory overlap with high cougar density areas predicted T. gondii infection.
• Seropositive wolves exhibited a higher likelihood of engaging in high-risk behaviors.
• These behaviors, such as dispersal and leadership, are critical for individual fitness and population vital rates.

Conclusions:

• Toxoplasmosis influences critical life-history decisions in wild wolves, impacting individual fitness.
• Behavioral changes in intermediate hosts can create feedback loops, potentially increasing parasite transmission between species.
• Parasites like T. gondii have significant implications for host behavior, group dynamics, and ecosystem processes, extending beyond acute infection effects.