A Generalist Predator Regulating Spread of a Wildlife Disease: Exploring Two Infection Transmission Scenarios

Abstract

Abstract. Ecoepidemiology is a well-developed branch of theoretical ecology, which explores interplay between the trophic interactions and the disease spread. In most ecoepidemiological models, however, the authors assume the predator to be a specialist, which consumes only a single prey species. In few existing papers, in which the predator was suggested to be a generalist, the alternative food supply was always considered to be constant. This is obviously a simplification of reality, since predators can often choose between a number of different prey. Consumption of these alternative prey can dramatically change their densities and strongly influence the model predictions. In this paper, we try to bridge the gap and explore a generic ecoepidemiological system with a generalist predator, where the densities of all prey are dynamical variables. The model consists of two prey species, one of which is subject to an infectious disease, and a predator, which consumes both prey species. We investigate two main scenarios of infection transmission mode: (i) the disease transmission rate is predator independent and (ii) the transmission rate is a function of predator density. For both scenarios we fulfil an extensive bifurcation analysis. We show that including a second dynamical prey in the system can drastically change the dynamics of the single prey case. In particular, the presence of a second prey impedes disease spread by decreasing the basic reproduction number and can result in a substantial drop of the disease prevalence. We demonstrate that with efficient consumption of the second prey species by the predator, the predator-dependent disease transmission can not destabilize interactions, as in the case with a specialist predator. Interestingly, even if the population of the second prey eventually vanishes and only one prey species finally remains, the system with two prey species may exhibit different properties to those of the single prey system.

Treatment of infected predators under the influence of fear-induced refuge

“…It is crucial to regulate the reproduction number to prevent exponential growth in infections during an outbreak (i.e., maintain it below 1 to bring the outbreak under control) 45 , 46 . The basic reproduction number ( ) can be computed using the next-generation matrix formula.…”

A modified Leslie–Gower predator–prey model with alternative food and selective predation of noninfected prey

“…Selective predation of infected prey is considered in some approaches 2,3,9,10 . In this scenario, infected prey may become weaker, less agile, and therefore more susceptible to predation.…”

Modelling in Ecology, Epidemiology and Ecoepidemiology: Introduction to the Special Issue

“…Another important new feature of the model is that the authors investigated the role of predator-dependent disease transmission, since although there are various known mechanisms through which the predation on the infected host can affect the transmission of disease (see [13]), the existing literature only considers predator-independent disease transmission. Sen et al [21] extensively explore how the predator-dependent transmission in the presence of a second dynamical prey can affect the resultant behaviour of the system. Paradoxically, even if the second prey cannot establish itself in the system in the long term, and therefore formally the equilibrium species densities are equivalent to the model with a single prey, the overall system behaves differently to the case of a specialist predator, where the second prey is always absent.…”

“…Sen et al [21] consider a novel epidemiological model where the predator is a generalist and the alternative food supply is a dynamical variable. This approach is quite different to most ecoepidemiological models, where the predator is generally considered to be a specialist [23].…”