Genetic Markers for the Identification of Three Australian Tick Species at Various Stages in Their Life Cycles

An allozyme electrophoretic study was conducted on different life cycle stages of 3 Australian tick species, Amblyomma limbatum Neumann, 1899, Aponomma hydrosauri (Denny, 1843), and Ixodes holocyclus Neumann, 1899. Sixteen enzymes encoding a presumptive 19 loci were of sufficient staining intensity and resolution to identify accurately the 3 species at either the larval, nymphal, or adult stage of the life cycle. For each species, the larvae, nymphs, and adults all had alleles in common at all 19 loci. However, fixed genetic differences were detected among the 3 species at 15 or 16 of the 19 enzyme loci examined. The large number of genetic markers that have been established from a limited sample volume (e.g., individual unfed larvae) allows accurate identification of the species at each life cycle stage. Data presented show that the technique of allozyme electrophoresis can provide genetic evidence for the identification of species at any life cycle stage even where life cycle stages are morphologically quite different.