Chromosomal and electrophoretic identification of a sample of Anopheles gambiae group (Diptera: Culicidae) from the island of Grand Comoros, Indian Ocean.

Abstract

A sample of ca. 115 larvae and 2 adults belonging to the Anopheles gambiae group of mosquitoes was obtained from Grand Comoros, an island in the Mozambique Channel. Chromosomal identifications were made of 20 females reared from the larvae. Nineteen of these and 39 other individuals were used in electrophoretic studies. All specimens were identified as Anopheles gambiae sensu stricto, an important malaria vector not previously recorded from the island. Male progeny from an artificial mating between a Comoros male and an An. gambiae s.s. colony female showed no signs of hybrid sterility. Polytene chromosomes obtained from the female progeny were fully synapsed. Electromorph frequencies for 4 enzyme systems are given, and the island population is compared with reported frequencies in the An. gambiae group on the East African mainland. A method is given for the use of polyacrylamide gels for identification of members of the complex. The banding patterns on the hind legs of 40 females conformed with the morphological characteristics reported for the An. gambiae/arabiensis species pair. Two females had intermediate leg-banding patterns. Where possible, all 3 techniques, chromosomal, electrophoretic, and morphological, were applied to single individuals.