抄録
In order to investigate the relationship between calendar age of mosquitoes and physiological age determined by the observations of ovarioles after Detinova (1962) the examinations were carried out at 25°C and 80-90% RH conditions with the colonies of Culex pipiens pallens which have been collected in Tokyo and maintaned in this laboratory. The results showed that by 24 hours after emergence the follicles developed from N stage by Detinova to the stage I by Christophers. The follicles remained to I stage unless the mosquito fed on blood meals, however they continued to grow and the diameter reached to around 80 microns on three days after the emergence then kept almost same size until blood feeding. By three days after emergence over the half number of female mosquitoes took the blood meals and after six days over 90% were observed to finish blood feeding and also mating, which was determined by the presence of sperms in the spermatheca. After engorgement the follicles started to develop; by three days they reached to V stage and the longer diameter grew from around 100 microns up to about 550-600 microns. However the actual ovipositions took place a little later, and it was six days after engorgement that more than half of examined mosquitoes had been found to lay eggs. In twenty four hours after oviposition the saclike dilatations formed at ovariole pedicels completed their contraction and made the relics, therefore a considerable part of mosquitoes which were obtained in the field and found to have one relic per ovariole, that is, determined of one physiological age, could be considered to have elapsed around ten days after emergence. The mosquitoes which finished the oviposition were found to refeed on animals in a remarkablly short period after laying eggs; by 15 hours after oviposition more than half of the mosquitoes were observed to reengorge still having sac-like dilatations in ovaries. Whereas the period required to make the second oviposition could be considered to be almost the same with that in the first gonotrophis cycle, the second egg-laying would occur around 16 to 17 days after the emergence of the mosquito. So the physiological age of two would correspond to around 16-17 days of calendar age in the majority of mosquitoes.
