GENETIC DISTINCTNESS OF SYMPATRIC FORMS OF AEDES AEGYPTI IN EAST AFRICA.

Abstract

Aedes aegypti is a complex species in the sense that morphological, physiological, and behavioral variation is greater than that encountered in most insect species (see e.g. Machado-Allison and Craig, 1972; McClelland, 1974; Trpis and Hausermann, 1975). In the Rabai District near Mombasa, Kenya, a particularly interesting evolutionary situation exists: two (or three) morphologically and behaviorally distinct forms of A. aegypti are sympatric. There is a light colored indoor (domestic) form which breeds in water pots customarily kept inside village huts. In forests adjacent to villages, a dark outdoor (sylvan) form of A. aegypti breeds in tree holes. Some authors (Trpis and Hausermann, 1975) recognize a third intermediate form (peridomestic) which breeds in disturbed areas such as coconut groves. Our previous publication (Tabachnick and Powell, 1978) was concerned with the population genetic structure of the indoor breeding form within and between villages. We showed that each village population is essentially a panmictic unit and that village populations separated by 1 km or less could show significant gene frequency differences. Gene frequencies were found to be stable for at least a year. This report is concerned with quantifying the genetic differences between the outdoor and indoor forms of A. aegypti in this area of Kenya. Of particular interest is the question, If these forms are sympatric and remain genetically distinct, should they be recognized as separate species?