Using molecules to identify the source of fruit fly invasions

Abstract

Fruit flies trapped or intercepted as part of inspection and surveillance activities could be the result of resurgent pest populations, incursions from offshore introductions, or intentional releases of sterile flies. Knowing the source of these flies can help a plant protection organization determine how to respond to an urgent detection and which pathways pose a greater risk of future pest introductions. In this chapter, we review how biological molecules, such as DNA, proteins, and stable isotopes, have been used to estimate the geographic and population source of tephritid fruit flies. The merits and limitations of molecules as source estimators are treated by molecule origin (i.e., nuclear DNA, mitochondrial DNA, allozyme, and isotope) and technique (e.g., endonuclease digestion, DNA sequencing, genomics, biogeochemical) to provide an overview of available methods. THe importance of experimental sampling, data interpretation, and data archiving are considered with reference to other insect and non-insect examples. Lastly, a case study of source estimation methods for the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), which has been particularly well studies in this respect, is reported based on published work and ongoing studies.