Research

The role of endosymbionts and parasitoids in the structure and dynamics of insect-plant-pathogen associations

Our interests lie in the complex ecological associations which exist between insects such as aphids, which are capable of transmitting pathogenic micro-organisms to plants, and the endosymbiotic (parasitic?) bacteria and insect parasitoids which interact with them. A particular focus of this interest is the way in which plant nutritional state, endosymbiont profile, and attack by parasitoids act separately or together to influence the efficiency with which aphids vector plant pathogenic viruses.

There is accumulating evidence that endosymbiont bacteria may have complex effects on the efficiency with which pathogenic plant viruses are transmitted. Aphids harbour a “primary” endosymbiont in the genus Buchnera, which synthesises certain nutritionally important amino acids, and without which the aphid will usually die. In addition to Buchnera there may be a variable complement of “secondary” endosymbionts, whose role is much less clear, but which almost certainly have significant fitness effects on the aphid host and consequently its efficiency in vectoring plant viruses, and the emphasis of our research in the immediate future will be to tease apart and quantify these complex trophic interactions

Our experimental and field work is complemented by a parallel programme aimed at developing novel mathematical models to describe the dynamics of such systems, and especially the dynamics of the plant disease as influenced by the other members of the trophic association. A particular aim of the experimental programme is to enable us to parameterise these models accurately so that the longer term dynamics of the system can be reasonably investigated.

Teaching