Developing monitoring systems for multiple pathogens

Insects, such as butterflies and moths, do not remain in the same place all of the time and, if food and climatic conditions allow, they may move into new habitats that are already occupied by other similar species. This process is sometimes called invasion and it is regarded as one of the major threats to biodiversity today. For example, the magpie moth is moving into heather moorland in the Orkneys in Scotland, which is already occupied by winter moths. Both of these species are pests because they destroy the heather, which is an important habitat for rare ground nesting birds. When you mix two moth species such as these it also means that diseases carried by each of them could possibly infect the other. We already know that both magpie moths and winter moths are infected with a number of different viruses that result in the death of the caterpillar stages. For the past three years we have collected samples of both types of caterpillars from ten sites in the Orkneys and tested them for the presence of some of the viruses. We are hoping to find out if the viruses in each species are starting to spread between magpie moths and winter moths. If they do, they may have an effect on the numbers of each of these insect species. In an extreme case, the spreading of virus diseases between these insects could virtually wipe out both populations. The difficulty we have in assessing the degree of intermixing of virus diseases is that we need to diagnose up to five different viruses in hundreds of insect samples. The aim of this project is to solve the problem of detecting several viruses in a single insect caterpillar and provide a way to do the same thing in hundreds of samples. We intend to do this with a method that is currently used in forensic medicine to identify criminals. It involves amplifying the genetic material of each virus and at the same time attaching dyes that are specific for each one. When the chemical reaction is finished, we can see how much of each dye there is in each insect and therefore how much of each virus is present. When we have analysed all of our samples, we can draw a picture of how the viruses are spreading between insect populations and the effect they are having on the numbers of magpie moths and wintermoths in the Orkneys.