How do land use and habitat characteristics affect abundance of mosquito larvae. Insights from aquatic habitats in the lake Manyara basin in northern Tanzania

Mosquitoes breed in a variety of aquatic habitats. However, what controls larvae abundance in these habitats is still controversial in different parts of the world. Moreover, how surrounding land use shapes suitability of aquatic habitats for mosquito breeding is also not well known in many countries. To study this, we sampled water, macroinvertebrates, and mosquito larvae from 60 temporary ponds, 60 container habitats and 164 small natural ground (SNG) habitats from four dominant land use types (agriculture, settlement, pastoralism, wildlife protection) in lake the Manyara basin (LMB)-northern Tanzania. Concentrations of NO3-N, NH4-N and OrthoPO4 were analyzed from water samples while levels of TDS, salinity, turbidity, pH, DOC, depth, chlorophyll-A and phycocyanin were determined in situ. We found that abundance of mosquito larvae in LMB was not associated with the type of land use. Abundance of mosquito larvae in temporary ponds was negligible for the recorded Anopheles gambiae s.l and Culex quinquefasciatus. Aquatic predators which were absent in container and SNG habitats ensured that abundance of mosquito larvae was very low in ponds. A. gambiae s.l were more abundant in SNG habitats where its abundance seemed to increase with the level of turbidity and proximity of breeding habitats to human habitation. C. quinquefasciatus and Aedes aegypti bred abundantly in container habitats. A. aegypti larvae were more abundant in smaller containers while C. quinquefasciatus were abundant in nutrient enriched containers with abundant cyanobacteria. Thus, in the LMB different mosquitoes utilize different breeding habitats where abundances of larvae are regulated by different factors.