Effects Of Parasite-mediated Life-history Traits And Allee Effect On Eco-epidemiological System

Parasitism can influence the population dynamics and species coexistence through parasite-mediated indirect effects on the host-parasite interactions.Recently,the effect of parasite-mediated life-history traits on the species coexistence and population dynamics,which has become a frontier and hot issue in mathematical ecology.Based on eco-epidemiological models,we here explore how the parasite-mediated intra-specific competition between susceptible and infected host individuals affects the species coexistence in intra-guild predation(IGP)systems.The impact of Allee effect on species persistence is obvious as the population density is very low,so we here further discuss the influence of different weak Allee effect on the eco-epidemiological system.In the thesis we mainly discussed five chapters.In Chapter 1,we summarize the concept,theory and research status of trait-mediated effects and Allee effect.In Chapter 2,the theory and model constructions of life-history traits with parasitic regulation are introduced.In Chapter 3,based on eco-epidemiological models,we further explore how the parasite-mediated trait effects on intra-specific competition between susceptible and infected host individuals,affect species coexistence and dynamic status in the intra-guild predation systems.In Chapter 4,considering the importance of Allee effect in regulating species coexistence and dynamic status,we finally discussed the effects of weak Allee effect in the eco-epidemiological model.In the last Chapter,we illustrated the summary and outlook.Through the research,we mainly draw the following new results:(1)Different parasite-mediated intra-competition traits can produce various impacts on species coexistence.The parasite-mediated relatively strong inter-competition of susceptible host populations will promote species coexistence in intra-guild predation systems,while the parasite-induced reduction in inter-competition of infected host populations will inhibit the species coexistence.(2)Various parasite-mediated traits may affect species coexistence in different ways: when inter-competition is strong,the parameters range for species coexistence is wide,but as inter-competition is weak,the parameters for species coexistence is narrow.(3)The weak Allee effect has an influence on both the predator and the prey,but the effect on prey is more obvious,and even lead to the extinction of the prey,which makes the coexistence area decrease.(4)The weak Allee effect makes the predator dominant,and increases the population density.(5)The larger weak Allee effect threshold is,the wider the area of only the predator or only the prey is,but narrow regions for the coexistence.Our research can therefore contribute to the development of eco-epidemiological theory,and explore the species coexistence in intra-guild predation systems,and then provide a theoretical basis for biodiversity conservation.