Infectious disease and social structure of Yellowstone wolves

Pathogens reduce the population size of Yellowstone wolves mainly by decreasing the number of social groups, a study finds. Living in a group has many advantages but comes at the cost of increasing pathogen transmission. Previously developed disease models have captured the effects of social groups on disease dynamics, but this approach does not consider the impact of pathogens on social organization. Ellen Brandell, Andrew Dobson, and colleagues developed a model to assess how pathogens affect the size and number of groups of Yellowstone wolves. The authors used demographic data from two decades of research on this population of wolves and focused on two of its pathogens: the mite that causes the skin disease sarcoptic mange and canine distemper virus. The presence of a pathogen reduces both the number of groups and the size of infected groups, allowing uninfected groups to grow large due to less intergroup aggression. The findings reveal that low disease prevalence at the population level can mask high disease prevalence in infected groups, underscoring the importance of sampling from many groups in a population for accurate assessments. According to the authors, this model framework could be used to better understand subtle interactions between infectious disease and the population structure of any social species, possibly helping to protect endangered animals.

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Article #20-20023:

“A metapopulation model of social group dynamics and disease applied to Yellowstone wolves,” by Ellen E. Brandell, Andrew P. Dobson, Peter J. Hudson, Paul C. Cross, and Douglas W. Smith.

MEDIA CONTACTS:

Ellen Brandell,

Pennsylvania State University, University Park, PA;

email: <

[email protected]

>;

Andrew Dobson,

Princeton University, NJ;

email: <

[email protected]

>