Community-wide analysis of horizontal symbiont transmission: oak gallwasps as a model system.

Many insects are infected by microorganisms, including bacteria called Wolbachia and Cardinium, that are passed from a mother to its offspring. These bacteria have a range of effects on the reproduction of their insect carriers, some of which are severe. Some of these bacteria have been proposed as a means by which harmful insects could be controlled. However, to plan for use of such approaches, we need to know if the bacteria involved can 'jump' (a process termed horizontal transmission) from one insect to another. This must happen, because very similar bacteria are commonly found in very different insects, but how it happens remains little understood. This project will look at a closely interacting set of insect species that inhabit a range of different galls on oaks. These communities consist of a specific set of prey species (the wasps that make the galls), and others that feed on them (primarily parasitic wasps). The project will assess the extent to which these two groups have exchanged bacteria, and test several hypotheses about which type of interaction are more likely to result in transmission.