Systematics of malaria vectors with particular reference to the Anopheles punctulatus group

The appearance of groups and complexes of closely related cryptic or sibling species in many of the anopheline taxa has impeded studies on malaria transmission and the evaluation of control strategies which have relied on morphological characters to identify the vector species involved. The advantages of morphological identification are low cost, speed and simplicity, which allow large numbers of specimens to be processed rapidly in the field. The need for accurate identification is crucial, as time and money may be wasted in studying and controlling species of no medical importance. Various techniques such as cross-mating, chromosome studies and allozyme analysis have been developed to resolve problems of identifying sibling species, though none, as yet, can match the speed and simplicity afforded by morphology markers. The latest of these identification methods comes from advances that have been made in DNA-based technology. Although costly and requiring fairly sophisticated laboratory support, methods such as DNA probe hybridisation and PCR are the quickest and most user-friendly to date. The use of DNA has other advantages in the study of intraspecific differences and in providing characters for phylogenetic studies. This review looks at the development of DNA-based techniques for taxonomic and systematic studies of anopheline mosquitoes. The Anopheles punctulatus group of the southwest Pacific is featured as an example of how this technology has been applied and how it has progressed.