AEDES-POLYNESIENSIS IN THE SOCIETY ISLANDS - ENVIRONMENTAL CORRELATESOF ISOENZYME DIFFERENTIATION

Isoenzyme genetic differentiation of Aedes polynesiensis mosquitoes in Raiatea island, French Polynesia, was evaluated by two models of popu lation structure based on seven gene-enzyme systems: Ak, Est, Got, Gpi , Hk, Mdh and Pgm. The ecological model tested whether genetic differe ntiation is congruent with habitat differences. The isolation model ev aluated whether genetic differentiation is proportional to geographica l distribution. The ecological model found no significant differentiat ion between populations of Ae.polynesiensis from beach and forest ecot opes, whereas the isolation model, was consistent with the data. Howev er, incipient speciation is opposed by the source-sink system of popul ation dynamics in such small neighbouring islands, where Ae.polynensie nsis extinction is readily followed by reinvasion causing considerable gene flow between island populations.