Development and survival of immature Culex annulirostris mosquitoes in southeast Queensland

The rates of development and survival of the immature stages of Culex annulirostris were studied in three different breeding sites in the Brisbane area of southeast Queensland: a temporary rain-filled pool (TP), a semi-permanent pool (SPP), and an area of flooded grassland (FG) arising from the overflow of a permanent pond. Parallel observations were made on larvae and pupae either exposed to predation or in predator-free cages of 12 and 15 consecutive days respectively. Development was fastest and survival highest in the warmer TP. Average daily mortality of larvae (L) and pupae (P) was TP: L 8.3%, P 9.5%; SPP: L 25.2%, P 34.6%; FG: L 18.8%, P 35.4%. From life-tables and survivorship curves, survival from first instar to adult was TP 34.8%, SPP 2.0% and FG 4.2%. Mortality from predation was TP 43.2%, SPP 68.7% and FG 69.1%. Predator density was TP 0.32, SPP 1.48 and FG 1.76 per 300 ml sample.