LARVAL COMPETITION IN AEDES TRISERIATUS (DIPTERA, CULICIDAE) - EFFECTS OF DENSITY ON SIZE, GROWTH, SEX-RATIO, AND SURVIVAL

We assessed the effect of increased larval density on selected life ta ble attributes of larval Aedes triseriatus. Larvae were reared at dens ities of 0.125, 0.250, and 0.375 larvae/cm(3) of water. The parameters we evaluated included duration of each developmental instar, percent survival to adult emergence, sex ratio, and size of early and late eme rging adults. The amount of time spent in the first and second instar was not affected by density, but crowding lengthened duration of later instars significantly. Males emerged earlier than females at all dens ities, and there was no difference in the ratio of males to females du e to crowding. Crowding did increase the overall developmental time of both sexes and produced significantly smaller adults of both sexes. D ensities of 0.375 larvae/cm(3) resulted in a significant increase in m ortality. Results suggest that the effects of crowding in container ha bitats should be allowed for in the construction of time-specific life tables where duration of larval instars is used in the calculations. The importance of smaller body size as a result of crowding in contain er habitats is discussed in terms of vector competence of Ae. triseria tus in the transmission of LaCrosse encephalitis virus.