The Allee effect and infectious diseases: extinction, multistability, and the (dis-)appearance of oscillations

Frank M Hilker, M Langlais, H Malchow

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96 Citations (SciVal)


Infectious diseases that affect their host on a long timescale can regulate the host population dynamics. Here we show that a strong Allee effect can lead to complex dynamics in simple epidemic models. Generally, the Allee effect renders a population bistable, but we also identify conditions for tri‐ or monostability. Moreover, the disease can destabilize endemic equilibria and induce sustained oscillations. These disappear again for high transmissibilities, with eventually vanishing host population. Disease‐induced extinction is thus possible for density‐dependent transmission and without any alternative reservoirs. The overall complexity suggests that the system is very sensitive to perturbations and control methods, even in parameter regions with a basic reproductive ratio far beyond . This may have profound implications for biological conservation as well as pest management. We identify important threshold quantities and attribute the dynamical behavior to the joint interplay of a strong Allee effect and infection.
Original languageEnglish
Pages (from-to)72-88
Number of pages17
JournalAmerican Naturalist
Issue number1
Early online date5 Dec 2008
Publication statusPublished - Jan 2009


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