Influence of Larval Population Density on Fluctuation in Mosquito Numbers

Abstract

RECENT ecological studies on culicine mosquitoes in and around a village in south-western Nigeria¹ revealed that the numbers of Aedes aegypti fluctuated throughout the year in a manner which could not be correlated with the observed external environmental factors. During a preliminary survey it was established that this species was restricted to breeding within the village area in clay water-pots of the type used for collecting and storing water, but that it was absent from natural habitats in the surrounding rain forest. The fact that it showed a typically domestic breeding pattern facilitated a study of the population dynamics throughout the year, and the method used for obtaining an index of breeding intensity was as follows. A number of clay pots were placed in tha village and sampled weekly, the pre-adults (larvæ and pupæ) being removed for counting while the pots were cleaned and refilled with fresh water. The number of pre-adults found weekly was taken as an index of the changes in density of the breeding population within the village.