Larval Competition Between the Introduced Vector of Dengue Fever in Australia, Aedes-Aegypti (L), and a Native Container-Breeding Mosquito, Aedes-Notoscriptus (Skuse) (Diptera, Culicidae)

Abstract

The introduced vector of dengue, Aedes aegypti, has disappeared from New South Wales at the same time as the indigenous Ae. notoscriptus has increasingly intruded into the domestic environment. Laboratory investigations of larval survival and development rates for both species, alone and in various combinations, at two temperatures under varying conditions of density and food, were conducted to test the hypothesis that the latter species had a competitive advantage. For both species, in intra- and interspecific competition, survival declined markedly, and development rate increased considerably, with increasing density and decreasing food in intra- and interspecific competition. Decrease in food supply had relatively greater effect than increase in larval density, although combining both had the greatest effects. Although the native Ae. notoscriptus had a marginal advantage over the introduced Ae. aegypti at 22°C, the situation was reversed at 28°C. Overall, however, the predominant species in mixed cultures was usually advantaged. The hypothesis was not proved, although the results indicated that Ae. notoscriptus may have a competitive advantage over Ae. aegypti in cooler areas when the former species is predominant.