Inbreeding is common in plant populations and can affect plant fitness and resistance against herbivores. These effects are likely to depend on population history. In a greenhouse experiment with plants from 17 populations of Lychnis flos-cuculi, we studied the effects of experimental inbreeding on resistance and plant fitness. Depending on the levels of past herbivory and abiotic factors at th...

A system of ordinary differential equations is considered that models the interactions of two plant species populations, an herbivore population, and a predator population. We use a toxin-determined functional response to describe the interactions between plant species and herbivores and use a Holling Type II functional response to model the interactions between herbivores and predators. In ord...

1. As plant invasions pose one of the greatest threats to biodiversity, it is critical to improve both our understanding of invasiveness and strategies for control. Much research into plant invasions and their management, including biological control, assumes strong demographic effects by natural enemies, including herbivores. However, the importance of natural enemies in the regulation of plan...

Aims We present an improved model for the growth of individuals in plant populations experiencing competition. Methods Individuals grow sigmoidally according to the Birch model, which is similar to the more commonly used Richards model, but has the advantage that initial plant growth is always exponential. The individual plant growth models are coupled so that there is a maximum total biomass f...

Results are presented from a three gene population genetics and dynamics model of herbicide resistance in annual ryegrass. The models predictions are compared with those of other one and two gene resistance models to validate the modelling approach which will ultimately be used to develop a five-gene herbicide resistance model. The importance of initial gene frequencies for resistance in unsele...

Pedigree selection was practiced on two bread wheat populations, namely i.e. (Debeira x Sahel 1) as considered population I and (Sids 6 x Sahel 1) as considered population II. Experiments were conducted under drought stress conditions (at 12 % soil moisture content) in order to improve yield and its component traits (no. of spikes / plant, biological yield, grain yield / plant and 1000-grain we...

We study the influence of random migration of a species (may be insects) in the population dynamics when initially all the individuals live in a primordial site (their habitats may be trees). We assume (i) a finite number of sites, (ii) that migration occurs randomly to nearest neighbors, and (iii) an on-site age-structured population whose size varies according to Ricker's map. We find that ev...

In this study, we examine the demographic consequences of mixed mating and explore the interactive effects of vegetative herbivory and mating system for population dynamics of Impatiens capensis, a species with an obligate mixed mating system (i.e., individuals produce both obligately selfing cleistogamous and facultatively outcrossing chasmogamous flowers). In two natural populations, we follo...