Effects of Temperature Stress on Pre-imaginal Development and Adult Ptero-fitness of the Vector Mosquito, Culex quinquefasciatus (Diptera: Culicidae)

Abstract

Day-old first instar larvae of Culex quinquefasciatus mosquitoes were cultured to imago eclosion, at constant temperatures of 30.00, 32.00, 34.00°C and ambient water temperature (28.00±0.02°C, Control). The duration and survivorship of larval and pupal life stages were monitored daily. The wings of adult mosquitoes were measured for length and fluctuating asymmetry. The results indicated significant (p<0.05) effects of water temperature on developmental indices investigated. The duration of larval and pupal stage was significantly shortened from 10.82±1.02 days (28.00±0.02°C) to 7.65±2.15 days (34.00°C) and 2.04±0.70 (28.00±0.02°C) to 1.19±0.27 days (34.00°C), respectively. Survivorship of immature stages showed inverse relationship with increasing water temperature; with survivorship of the pupae significantly higher than those of the larvae at all the temperatures tested. Wing length and fluctuating asymmetry were also affected by rise in temperature. The findings of this study indicate limited thermal adaptation of Cx. quinquefasciatus to relatively warm areas; this information should help in developing effective environmental mosquito-vector control against the species by the discouragement of ecological settings that may reduce micro-climatic temperatures around breeding habitats of the mosquito species.