Elongation of in vitro cultured ovarian follicles in the mosquito, Culex pipiens pallens.

Ovarian follicles dissected from female Culex pipiens pallens 3 d after a blood meal were cultured in PBS-based medium and morphological changes were recorded as time-lapse movies. The dissected follicles, already reaching stage III, were ovoid in shape, ca 300 μm long, and 180 μm wide. The oocyte had almost finished yolk protein uptake, and the cytoplasm was filled entirely with yolk granules.

Follicular epithelial cell apoptosis of atretic follicles within developing ovaries of the mosquito Culex pipiens pallens.

Follicular atresia, the degeneration of developing follicles, is always incident to normal oogenesis in both oviparous and viviparous animals. Photo- and electron-microscopic observation of degenerating follicles within developing ovaries taken from blood-fed Culex pipiens pallens mosquitoes showed gradual degradation of the internal structures including yolk granules in the oocyte. The epithelial cells, which sometimes incorporated yolk granules from the oocyte along with the shrinkage of the follicle, gradually lost their uniform columnar shape, while their integrity as a covering layer remained.

Insemination rates of hybrids between Culex pipiens pipiens and Culex pipiens quinquefasciatus or Culex pipiens pallens at high temperature.

Females of Culex pipiens pallens are rarely inseminated at temperatures above 30 degrees C. Insemination and egg-hatching rates (F2) were examined in females of hybrids (F1) between Culex pipiens pipiens and Culex pipiens quinquefasciatus at 25 degrees C and 30 degrees C to examine temperature-dependent reproductive activity. Insemination rates were very high in hybrid females (F1) at 25 degrees C and 30 degrees C, and egg-hatching rate (F2) also was high at both temperatures.

Effects of mating on oogenesis induced by amino acid infusion, amino acid feeding, or blood feeding in the mosquito Anopheles stephensi (Diptera: Culicidae).

Hemocoel infusion of an amino acid mixture at a concentration of 7.5% and 10% (wt:vol) for 24 h rarely activated ovarian development in either mated or unmated females of Anopheles stephensi Liston. Infusion of either concentration mixture for 48 h into unmated females was also scarcely stimulatory, but the same 48 h infusion into mated females resulted in ovarian maturation in 25% (7.

Ovarian development induced in decapitated female Culex pipiens pallens mosquitoes by infusion of physiological quantities of 20-hydroxyecdysone together with amino acids.

Infusion of 20-hydroxyecdysone into the hemocoel of unfed decapitated female Culex pipiens pallens mosquitoes, at a very low rate of 500-2000pg per day, often stimulated oögenesis of this species, when the hormone was infused together with amino acids. The hormone alone or amino acids alone showed no such stimulatory effect. Previous reports that using an abdomen ligated immediately after a blood meal for hormone injection reduced the quantity of 20-hydroxyecdysone needed to activate unfed female Aedes aegypti by a few thousand times, are therefore due mainly to a sufficient supply of amino acids from the midgut in the isolated abdomen.

Laboratory studies of Ochlerotatus samoanus in association with leaf axils of Freycinetia (Pandanaceae) in Samoa.

Three species of Freycinetia (Pandanaceae) (F. reineckei, F. storkii, and F.

Reproductive activity and survival of Culex pipiens pallens and Culex quinquefasciatus (Diptera: Culicidae) in Japan at high temperature.

The egg hatchability, insemination, and longevity of Japanese Culex pipiens pallens Coquillett and Japanese Culex quinquefasciatus Say were compared at 25 and 30 degrees C. Egg hatchability was high in Cx. p.