Presentation Type
Oral Presentation
Category
STEM (science, technology, engineering, mathematics)
Abstract/Artist Statement
Toxoplasma gondii is a protozoan parasite capable of infecting any warm-blooded species yet, requires a feline definitive host to sexually reproduce. Experimental studies indicate that T. gondii infection increases an individual’s risky decision-making but, due to the intensive data collection and large samples sizes necessary, T. gondii’s role in ecosystem processes is understudied.
We sought to understand the role in which T. gondii exposure affects gray wolf decision-making in Yellowstone National Park. To achieve this, we used 25 years of wolf serological and behavioral data to build generalized linear mixed models (GLMMs) to test for a change in behavior of gray wolves after exposure. We examined the effect of seropositivity on four behaviors associated with risk taking: (1) dispersal, (2) achieving dominant social status (i.e., becoming pack leader), (3) approaching people or vehicles (i.e., habituation), and (4) dying of a specific cause, measured two ways: intraspecific mortality or anthropogenic mortality. We demonstrate that T. gondii infection directly affected the probability that a wolf became a pack leader or dispersed by 46 and 11 times, respectively, compared to seronegative wolves.
This study helps to unlock the complexity of parasite-host-ecosystem dynamics. The wolf behaviors associated with infection (i.e., dispersal and leadership) have the potential to impact vital rates at the individual, group, population, and ecosystem levels through subsequent changes in reproduction and survival of those exposed to T. gondii. Our study reveals an important and novel link between T. gondii infection and behavioral alterations in a free-living wildlife population.
Mentor Name
Mark Hebblewhite
Personal Statement
Parasites have long been the subject of study due to their ability to affect host survival and reproduction. However, research in laboratory studies observed parasites’ ability to affects hosts in non-lethal ways, including parasite induced behavioral changes. However, in wild population studies, behavioral research is incredibly difficult to conduct due to the large, long term datasets required for strong statistical inference. The Yellowstone Wolf Project (YWP) is home to one of the largest carnivore datasets in the world. Here, the YWP provided over 26 years of wolf behavioral, demographic, and serological data to understand the role of a protozoan parasite (Toxoplasma gondii) in affecting wolf behavior. We used this data to detect and estimate significant behavioral changes in wolves infected with T. gondii, only the second study in the world to ever do so on a wild carnivore population. Since publication in late November 2022, T. gondii’s ability to alter host behavior in wolves, has captured the attention of the general public and scientists all over the world. We have been interview by CNN, BBC Wildlife, NPR, Canadian Broadcasting Company, and over 120 local and international news agencies. Additionally, our research has shared to almost 10 million twitter users and is currently the top 99.998% of all scientific publications measured by Altmetric (~23 million publications). Beyond media attention, our research provides clear and significant evidence of a parasites ability to alter host behavior. Additionally, as wolves are considered keystone species in Yellowstone National Park, where their absence contributed to negative ecosystem effects. As T. gondii alters wolf behavior (and capable of infecting any warm-blooded species on earth), so too may it affect ecosystem processes. The results from this study, and cascading effects of T. Gondii, drastically alters how ecologists should think about ecosystem processes and dynamics moving forward.
Connor Meyer_Gradcon 2023_Video Entry
Parasitic Infection in a Social Carnivore: T. gondii Exposure Increases Risky Decision Making in Gray Wolves
UC 330
Toxoplasma gondii is a protozoan parasite capable of infecting any warm-blooded species yet, requires a feline definitive host to sexually reproduce. Experimental studies indicate that T. gondii infection increases an individual’s risky decision-making but, due to the intensive data collection and large samples sizes necessary, T. gondii’s role in ecosystem processes is understudied.
We sought to understand the role in which T. gondii exposure affects gray wolf decision-making in Yellowstone National Park. To achieve this, we used 25 years of wolf serological and behavioral data to build generalized linear mixed models (GLMMs) to test for a change in behavior of gray wolves after exposure. We examined the effect of seropositivity on four behaviors associated with risk taking: (1) dispersal, (2) achieving dominant social status (i.e., becoming pack leader), (3) approaching people or vehicles (i.e., habituation), and (4) dying of a specific cause, measured two ways: intraspecific mortality or anthropogenic mortality. We demonstrate that T. gondii infection directly affected the probability that a wolf became a pack leader or dispersed by 46 and 11 times, respectively, compared to seronegative wolves.
This study helps to unlock the complexity of parasite-host-ecosystem dynamics. The wolf behaviors associated with infection (i.e., dispersal and leadership) have the potential to impact vital rates at the individual, group, population, and ecosystem levels through subsequent changes in reproduction and survival of those exposed to T. gondii. Our study reveals an important and novel link between T. gondii infection and behavioral alterations in a free-living wildlife population.