[Daily and seasonal changes in the oviposition activities of Culex pipiens pipiens L. (author's transl)].

The oviposition activity of C. p. pipiens during summer and autumn has been investigated at two breeding sites in West and North Germany. The egg rafts were collected and counted daily or hourly. Soon after its begin oviposition reached a high peak and then decreased sharply and faded out towards sunrise. There was an obvious correlation between the hourly maximum number of egg rafts deposited and nightfall. The peak of oviposition regularly followed the sunset with one hour delay. It shifted with the changing daylight period according to the season and geographic latitude. The decrease and ending of the oviposition in September is considered not to be related to the decreasing temperatures, but to be due to the disappearance of the gonoactive summer generation and the predominance of the diapausing females of the over-wintering population.