Isozyme evidence for three sibling species in the Anopheles sundaicus complex from Indonesia

Electrophoretic studies of isoenzymes in three chromosomally distinct forms (A, B and C) of the mosquito Anopheles sundaicus Theobald (Diptera: Culiciae) were undertaken on wild samples collected from six geographically isolated populations in Indonesia. Analyses of 12 enzyme systems comprising 15 loci revealed significant allelic variations, genetic polymorphism, within and among the populations of the An. sundaicus complex. Phylogenetic dendrograms produced by analysis using the Biosys-1 program based on UPGMA methods show that all the populations of form A fall into one cluster, which is closely related to the form C cluster, whereas the populations of form B belong to a more distinct cluster. Allelic frequency and Wright's F statistics of Mpi (mannose phosphate isomerase) are sufficient to identify individuals of each cytological form. This isozyme data correlates with our previous cytological evidence for the existence of three isomorphic species within the taxon An. sundaicus in Indonesia. These three species of the An. sundaicus complex were found together sympatrically at one locality, Asahan in North Sumatra.