Ecology and Evolutionary Biology Commons^™

A Theoretical Perspective On Parasite-Host Coevolution With Alternative Modes Of Infection, George N. Shillcock

Electronic Thesis and Dissertation Repository

We investigate how natural selection shapes the coevolution of parasitism. We discuss the antagonism fuelled by parasites’ necessity to transmit to novel hosts, and host’s desire to minimise virulence. In support, we build a mathematical model which considers the epidemiology and life-history trade-offs faced by an obligate microparasite and its host. Our model allows parasites to be transmitted to new hosts via direct contact (horizontally) or from parent to offspring during birth (vertically). We test the hypothesis that vertical transmission causes virulence to diminish in the long run, and contrary to widely accepted views, find that vertical transmission need not …

Population And Evolution Dynamics In Predator-Prey Systems With Anti-Predation Responses, Yang Wang

Electronic Thesis and Dissertation Repository

This thesis studies the impact of anti-predation strategy on the population dynamics of predator-prey interactions. This work includes three research projects.

In the first project, we study a system of delay differential equations by considering both benefit and cost of anti-predation response, as well as a time delay in the transfer of biomass from the prey to the predator after predation. We reveal some insights on how the anti-predation response level and the biomass transfer delay jointly affect the population dynamics; we also show how the nonlinearity in the predation term mediated by the fear effect affects the long term …

Ecological Constraints And The Evolution Of Cooperative Breeding, David Mcleod

Electronic Thesis and Dissertation Repository

Cooperative breeding is a social behaviour in which certain individuals will opt to delay or forgo their own reproduction in order to help other individuals. Cooperative breeding is one of the most conspicuous examples of cooperation in nature. However, theoretical understanding of why this behaviour occurs is lacking and contradictory. In this thesis, I examine the role played by ecological constraints on the emergence of cooperative breeding. Contrary to previous results, I find that ecological constraints do matter, provided the population dynamics are properly accounted for. I also examine the long-term evolutionary dynamics of cooperative breeding, and obtain the optimal …