FoxSimAn individual-based population model

of foxes and sarcoptic mange

Gösta Nachman and Mads C. Forchhammer

Department of Population Ecology

Zoological Institute

University of Copenhagen

Mads C. Forchhammer and Tommy Asferg: ”Invading parasites cause a structural shift in red fox

dynamics”

Proceedings of the Royal Society B (2000), 267, 779-786

Sarcoptic mange is a skin disease

• It is caused by the mite Sarcoptic scabiei var. vulpes

• Latency period from exposure is approximately one month

• The mite causes severe skin lessions and loss of hair

• Infected foxes usually die from starvation

• Infected animals normally live 7-8 months as compared with 3-4 years of heathy individuals

• Recovery from mange is rare

Photo Credit To: Clyde Isaak, Jamestown, N.D.

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Fox territoryMale fox

Female fox

Offspring

Offspring leave parent’s territoryin order to establish their own

Single foxes tend to leave a territory

Mortality during dispersal depends on distance

Fight to gain territory

Infected maleHealthy female

Infected offspring

Infected pairs produce less offspring

Sick individuals infect healthy ones by physical contacts

Healthy individuals have higher mating chance

Infected individuals have reduced fitness

Sick individuals never recover from the disease

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