Mycobacterium tuberculosis (M.tb), the cause of tuberculosis (TB), is estimated to infect a new host every second. While analyses of genetic data from natural populations of M.tb have emphasized the role of genetic drift in shaping patterns of diversity, the influence of natural selection on this successful pathogen is less well understood. We investigated the effects of natural selection on pa...

The innate immune system is an ancient and broad-spectrum defense system found in all eukaryotes. The detection of microbial elicitors results in the up-regulation of defense-related genes and the elicitation of inflammatory and apoptotic responses. These innate immune responses are the front-line barrier against disease because they collectively suppress the growth of the vast majority of inva...

The sweetpotato whitefly, Bemisia tabaci biotype B is extremely polyphagous with >600 species of host plants. We hypothesized that previous experience of the whitefly on a given host plant affects their host selection and performance on the plants without previous experience. We investigated the host selection for feeding and oviposition of adults and development and survival of immatures of th...

Host race formation in phytophagous insects can be an early stage of adaptive speciation. However, the evolution of phenotypic plasticity in host use is another possible outcome. Using a reciprocal transplant experiment we tested the hypothesis of local adaptation in the aphid Brevicoryne brassicae. Aphid genotypes derived from two sympatric host plants, Brassica oleracea and B. campestris, wer...

Laboratory selection for fenvalerate resistance was conducted in two colonies of the parasitoid, Cotesia plutellae, reared on two colonies of its host, Plutella xylostella, which differed in resistance to the insecticide. In the selection regime, the insecticide was applied to the host larvae that harboured the parasitoid larvae. Compared with the unselected parasitoid colony, the parasitoid co...

Knowledge of virus genes under positive selection pressure can help identify molecular determinants of species-specific virulence or host range without prior knowledge of the mechanisms governing host range and virulence. Towards this end, codon-based models of substitution were used in a maximum-likelihood approach to analyse selection pressures acting on 83 genes of group I nucleopolyhedrovir...