ABUNDANCE AND AGE STRUCTURE OF THE PREDATORY MOSQUITO LARVA, TOXORHYNCHITES TOWADENSIS (DIPT, CULICIDAE) IN RELATION TO PREY COMMUNITY STRUCTURE

The larval ecology including the abundance and age structure of the pr edatory mosquito larva, Toxorhynchites towadensis, was studied in rela tion to prey community structure. The number of larvae observed per po ol was small. The larvae living in each pool were of same instars and 86% were fourth instars. Females of T. towadensis laid a number of egg s into one oviposition cup irrespective of the existence of conspecifi c larvae in the laboratory. These results suggest that intense canniba lism by fourth instars to younger larvae occurred in the field. Seven species of mosquitoes including two predatory species, T. towadensis a nd Culex halifaxii, were observed. The number of prey larvae in pools decreased with an increase of the number of larvae of T. towadensis an d the development of the predator. Aedes albopictus was the dominant s pecies in the pools without T. towadensis. However, in the pools with T. towadensis larvae, the dominant species was Orthopodomyia anopheloi des. Therefore, the prey community structure seems to be shifted by th e predatory larvae.