This thesis first introduces stochastic disturbance factor into a model and has a discussion of it on the basis of a predator-prey system of three species with age-structure proposed by Zhixue Luo. Sufficient conditions of a stochastic disturbance predator-prey system of three species with age-structure have been given and exponential stability of strong solution has been proved according to Gr...

ladybird hippodamia variegata (goeze) (coleoptera: coccinellidae) has been reported from many parts of iran, has an important factor on equilibrium and natural regulation of acyrthosiphon pisum (harris) (hem.: aphididae) population in alfalfa. determining the population seasonal change of h. variegata and its parasitism rate by the most important parasitoid species was the aim of this study. th...

Recent studies have increasingly recognized evolutionary rescue (adaptive evolution that prevents extinction following environmental change) as an important process in evolutionary biology and conservation science. Researchers have concentrated on single species living in isolation, but populations in nature exist within communities of interacting species, so evolutionary rescue should also be ...

Multi-species Lotka-Volterra models exhibit greater instability with an increase in diversity and/or connectance. These model systems, however, lack the likely behavior that a predator will prey more heavily on some species if other prey species decline in relative abundance. We find that stability does not depend on diversity and/or connectance in multi-species Lotka-Volterra models with this ...

A dynamic systems approach to evolutionary branching and its development in an artificial food web is presented. Predator-prey interaction among trophic species with two traits generates a variety of evolutionary branching patterns, depending on interaction strengths and mutation rates. Studying branching patterns in a phenotypic space reveals three branching patterns: prey-bifurcation, predato...

1. Size relationships are central in structuring trophic linkages within food webs, leading to suggestions that the dietary niche of smaller carnivores is nested within that of larger species. However, past analyses have not taken into account the differing selection shown by carnivores for specific size ranges of prey, nor the extent to which the greater carcass mass of larger prey outweighs t...

Differences in boldness are common between populations or between related species and are discussed as part of individual coping style, personality, or behavioral syndrome. Boldness has been found to be dependent on experience, social, and environmental contexts. The major aim of the present study was to establish an experimental environment that would allow analyzing the risk-taking behavior o...

Emerging infectious diseases have been identified as threats to biodiversity, yet our understanding of the factors contributing to host susceptibility to pathogens within natural populations remains limited. It has been proposed that species interactions within communities affect host susceptibility to pathogens, thereby contributing to disease emergence. In particular, predation risk is a comm...

BACKGROUND Predators can have profound impacts on the dynamics of their prey that depend on how predator consumption is affected by prey density (the predator's functional response). Consumption by a generalist predator is expected to depend on the densities of all its major prey species (its multispecies functional response, or MSFR), but most studies of generalists have focussed on their func...