Effect of Salinity on the Development and Emergence of Anopheles Larvae

Abstract

Mosquitoes are insects in the order Diptera with the two main subfamilies Anophelinae and Culicinae. Mosquitoes exploit all kinds of lentic habitats for breeding: natural breeding habitats (e.g. ponds, swamps, streams etc.) or artificial breeding habitats (e.g. ditches, pits, construction sites, gutters, tyre tracks, cans etc). Prevailing physicochemical variables in these breeding habitats are essential factors for the survival, development and adult emergence of mosquitoes. This study aimed to investigate the impact of salinity on the emergence and development of Anopheles larvae. Anopheles larvae were collected at Lamingo, in Jos-North Local Government Area (LGA) and physicochemical parameters of the habitats were measured to establish a range for salinity treatments. Larvae were exposed to four salt concentrations (0.125g/ml, 0.25g/ml, 0.375g/ml and 0.5g/ml) to assess the survival, mortality, development of the larvae and emergence of the adult mosquitoes in every of the treatment solutions. A generalized linear mixed model (GLMM) with poison link distribution was used to test the impact of pH, temperature and salinity on the survival, development and emergence of adult mosquitoes. There was no significant influence of salinity on the survival of Anopheles larvae (p>0.05). However, as salinity increases, survival of Anopheles larvae decreases. However, there was a positive significant influence (p<0.05) of salinity on the mortality of Anopheles larvae, showing an increased mortality with increasing salinity levels. Furthermore, it was observed at a salinity concentration of 0.375g/ml, that the rate of larval development and adult emergence was significantly high (p<0.05) compared to the other concentrations. The results of this study suggest further research in this area to harness the possibility of using salinity levels as a mosquito control tool.