Abstract
The interference of the larval populations of Culex pipiens molestus was studied in the successive cultures by introducing groups of 200 or 500 1st-instar larvae in several day intervals. The pupation rates (survival rates of larvae) varied from 88.5% to 4.3% depending on the absence or presence of the interstadial interference. The alternative decreases and increases of the pupation rates in the successive populations demonstrated the self-regulation of mosquito larvae by means of short-living interference chemicals. The percentages of emergence and oviposition, and the day intervals required for larvae to pupate showed no significant interference effects. The mean numbers of eggs in a raft, however, showed slight decreases as the introduction of new populations was repeated. The reproduction capacity (numbers of eggs produced per larva), which are the multiple products of the above figures, also showed the pronounced ups and downs depending on the size of the preceding surviving larval population. The reproduction capacity, 14.9 of the 200 larva populations in the beginning decreased to 1.2 in the 8th population, and 6.9 of the 500 of larva populations ended at 0.9 in the 7th population. The interstadial as well as intrastadial interference of mosquito larvae therefore not only regulates their own population but governs the sizes of the following generations. The importance of larval density in the population dynamics of mosquitos was stressed.
