The genomic age heralded the arrival of an ability to understand the complete molecular structure of organisms. This created a wealth of information and know-how that found applications in many branches of biology and one was to lead to molecular ecology. This is the application of DNA (marker) technology to distinguish different parts of a population (usually individuals) and subsequently understand how the different genotypes interact with the environment. At SCRI, this has been placed firmly in an agricultural context with the study of pest insects and mites, but these are also part of the natural vegetation system.

Clearly, the starting point of any study, including those described below, has to be a description of what a pest is and where it can be found. Over the last decade the molecular ecology of pests has dramatically changed the way that biologists and breeders view the organisms that they are trying to control. Some of the achievements of our work include the following.

• Cecidophyopsis mites sub-divided into distinct host specific species. Read more in Case Study One.
• Uniform populations of raspberry aphids (biotypes) subdivided into individuals sharing only one gene.
• North American and European raspberry beetles shown to be derived independently through convergent evolution. Find out more in Case Study Two.
• Clonal diversity of the peach-potato aphid established and related to crop and insecticide resistance. Discover more in Case Study Three.

The possibilities for further research are limitless. Already core work is exploiting markers for M. persicae to follow movement in different vegetation systems, including the mini-rotation experiment. This will contribute generic knowledge on how insects move in a heterogenous environment. DNA markers have also found application in helping to understand the breakdown in control of M. persicae in Scotland in 2001.

Selected references

Fenton, B., Birch, A.N.E., Malloch, G., Lanham, P.G and Brennan, R.M., Gall Mite Molecular Phylogeny and its Relationship to the Evolution of Plant Host Specificity (2000). Experimental and Applied Acarology 24, 831-861.

Birch, A.N.E., Fenton, B., Malloch, G.M., Jones, A.T., Phillips, M.S., Harrower, B.E., Woodford, J.A.T. and Catley, M. A.,  Ribosomal spacer length variability in the large raspberry aphid, Amphorophora idaei (Aphidinae: Macrosiphini) (1994). Insect Molecular Biology 3, 239-245.

Malloch, G., Fenton, B. and Goodrich M. A., Phylogeny of raspberry beetles and other Byturidae (Coleoptera) (2001). Insect Molecular Biology 10, 281-291.

Fenton, B., Woodford, J.A.T and Malloch G., Analysis of clonal diversity of the peach-potato aphid, Myzus persicae (Sulzer), in Scotland and evidence for the existence of a predominant clone (1998). Molecular Ecology 7, 1475 - 1487.