Effect of Controphic Species on Natural Population Dynamics of Malaria Mosquito larvae on Rusinga Island

Abstract

Controphic species are organisms that share the same trophic levels within an ecosystem.Ecological theory and empirical research show that controphic species affect mosquito larval populations through predation or competition. The goal of this study was to identify controphic species that may serve as potential biological control agents for malaria mosquito larvae. A baseline survey of the abundance and diversity of malaria mosquito larvae (target species) and assemblages of their controphic species in breeding sites present on Rusinga Island was conducted. The effects of physicochemical factors on mosquito larval dynamics were also evaluated. The Renyi, Inverse Simpson and Shannon diversity indices established the presence of 35 controphic species in all habitat types studied. Redundancy analysis showed a positive correlation between the Anopheles species abundance with oxygen availability and levels of conductivity, salinity, pH and turbidity in decreasing order of importance .Anopheles species abundance had a negative correlation with depth, volume of water and distance of the larval habitat from the nearest house.Competitors contributed largely to the variation seen in the abundance of L1/L2 Anopheles larvae (R2 = 77.2%). The predators had a negative effect on abundance of the L1/L2 Anopheles larvae (R2 = 24.76%). The study demonstrates that assemblages of controphic species modulate the population dynamics of Anopheles mosquito larvae and are also affected by the physicochemical environment in the mosquito larval habitats.