Behaviour 2019
Associations between Toxoplasma gondii infection and steroid hormone levels in spotted hyenas.
Zachary M. Laubach1,2, Eben Gering3, Erik Yang3, Tracy M. Montgomery4, Thomas Getty2, Kay E. Holekamp2. 1University of Colorado, Boulder, Boulder, Colorado, United States; 2Michigan State University, Lansing, Michigan, United States; 3Nova Southeastern University, Fort Lauderale, Florida, United States; 4Max Planck Institute of Animal Behavior, Konstanz, , Germany

Toxoplasma gondii is a widely distributed parasite that infects warm-blooded animals and influences host physiology. T. gondii is known to encyst in the host’s central nervous system affecting circulating levels of steroid hormones, fear-related behaviors, and health, although these effects appear to vary among host taxa. Here, we investigated the relationship between T. gondii infections and levels of plasma testosterone and cortisol within a wild population of spotted hyenas (Crocuta crocuta), n = 109. We detected a negative association between circulating plasma testosterone and T. gondii infections among female cub and subadults as well as adult male hyenas. We found no associations between T. gondii infection and cortisol in any age class or sex group of hyenas. Our work adds to a growing body of literature by characterizing the relationship between T. gondii infection and physiology in a novel host in its natural habitat. In a broader context, our findings suggest that responses to infection may depend on characteristics of the host and point to a clear need for additional studies and priorities for future work that include diverse taxa.