Effects of Water Hardness Level on Metabolic Reserves of Post-Embryonic Life stages of Culex quinquefasciatus Say 1826 (Diptera: Culicidae).

Abstract

Metabolic Reserve (MR) is critical for success of adult mosquitoes, and its availability across life stages of mosquitoes is affected by abiotic factors such as water hardness. We investigated the influence of water hardness levels on MR in Culex quinquefasciatus, vis-à-vis its accumulation, mobilisation and utilisation for metamorphosis. First larval instars of the species were reared in five simulated water hardness regimens (0, 30, 90, 150 and 210 mg/L CaCO3) till adulthood following standard protocols. Life stage accumulation of MR components (lipid, protein, glucose and glycogen) and its utilisation for pupation and eclosion were quantified following standard protocols. Analyses revealed significant influence of water hardness on MR at all life stages of Cx. quinquefasciatus. MR components increased with development and larval age, and peaked at last larval instar. Water hardness level ≥ 90 mg/L CaCO3 elicited decrease in all reserve components. Reserve components’ daily accumulation rates were highest at 90 and and lowest at 210 mg/L CaCO3. Glycogen was the most accumulated MR components at all regimens. Significantly higher reserve component were utilised for pupation and eclosion at regimen ≥ 150 mg/L CaCO3. The information generated from this study would be useful in developing novel vector control technologies through habitat manipulation.