The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodo...The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodoptera litura （F.） are described. Chlorfluazuron was applied topically to newly-ecdysed fifth-instar larvae of S. litura under laboratory conditions. During first day of pupation, spermatids were the highest （3,430 ± 7）, however, elongated spermatocytes with mature sperm were the lowest （292 ± 16） in number in pupal-testis compared with other developing spermatocytes. During last day of pupation, elongated spermatocytes with mature sperm were the highest （3,581 ± 3）, however, spermatogonia were the lowest （86± 4） in number in pupal-testis compared with other developing spermatocytes. The number of spermatogonia, primary and secondary spermatocytes, spermatids and elongated cysts with mature sperm were increased during pupal-developmental days in the controls. However, their numbers were significantly reduced in LD10- and even more significantly reduced in LD30-treated pupal-testis compared with controls. Moreover, eupyrene sperm bundles were not present in pupal-testis. During pupal-developmental days, spermatids were the smallest （4.1 ± 0.9 dm in μm） and secondary spermatocytes were the largest （31.0 ± 1.8 dm in μm） in size compared with other developing spermatocytes. The sizes of the same developing spermatocytes were significantly reduced in LD10-treated and more significantly reduced in LD30-treated pupal-testis of S. litura compared with controls.展开更多
This paper describes effects of sublethal-doses of chlorfluazuron on morphology of embryogenesis when LD10 （1.00 ng/larva） or LD30 （3.75 ng/larva） was applied topically to newly-ecdysed fifth-instars of common cut...This paper describes effects of sublethal-doses of chlorfluazuron on morphology of embryogenesis when LD10 （1.00 ng/larva） or LD30 （3.75 ng/larva） was applied topically to newly-ecdysed fifth-instars of common cutworm, Spodoptera litura F.. Experiments were conducted on eggs of F1 generation laid by subsequent adults under laboratory conditions. Fecundity was significantly reduced by LD10 and more significantly reduced by LD30 compared with untreated females. Number of unfertilized-unhatched-eggs was not significantly affected by the treatments, Fertilized eggs revealed changes in external coloration of eggs. Embryonic development of S. litura was divided into eight embryonic stages. During stage 5 （12-16 h after oviposition）, in LD10-treated-egg, crescent-shaped-embryo was affectedly differentiated. During the same stage, it was seriously affected in LD30-treated-egg. During stage 7 （32-64 h after oviposition）, in LD10-treated-egg, organogenesis was established, but body structures were affectedly developed. In LD30-treated-egg, body structures were more affectedly developed during the same stage. It is concluded that embryonic developmental stages were affected by LD10 and more seriously affected by LD30. The effects of residualchlorfluazuron on embryogenesis are thought to be one of the factors responsible for the reduction in fertility and hatchability caused by sublethal doses of chlorfluazuron in S. litura.展开更多
Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD3o： 3.75 ng/larva） of chlorfluazuron on sper...Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD3o： 3.75 ng/larva） of chlorfluazuron on spermatogenesis in the adults of the common cutworm, Spodoptera litura （F.）. Chlorfluazuron was applied topically to the newly-ecdysed fifth-instars ofS. litura under laboratory conditions. The secondary spermatocytes, spermatids, elongated spermatocytes with mature sperm and eupyrene sperm bundles were present in testis of newly emerged, 1 and 2 day-old adults, but gradually decreased in their numbers in the controls. However, the spermatogonia were not present in newly emerged, 1 and 2 day-old adults. Moreover, primary spermatocytes were present （174 ± 4.0） in newly emerged adults, but not found in 1 and 2 day-old adults. In the testes of newly emerged LD10-treated adults, the numbers of eupyrene and apyrene sperm bundles were significantly reduced compared with controls, and even significantly reduced in LD30-treated adults compared with LDlo, however, their ratios were not affected. Moreover, the pattern of spermatogenesis was the same in LD10- and LD30-treated male adults compared with controls. Furthermore, numbers of developing spermatocytes were significantly reduced in the LD10 compared with controls, and even significantly reduced in LD30-treated male adults compared with LD10. In newly emerged adults, the width and length of elongated spermatocytes with mature sperm were significantly reduced in LDlo- and more significantly reduced in LD30-treated compared with controls of S. litura. In vas deferens of untreated pre- and newly emerged adult male, both eupyrene and apyrene sperm bundles were found, however, in treated pre-adult male, only apyrene sperm bundles and in treated newly emerged adult male, fe, w eupyrene and numerous apyrene sperm bundles were found. It is concluded that spermatogenesis was significantly affected by chlorfluazuron.展开更多
Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD30：3.75 ng/larva） of chlorfluazuron on ovari...Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD30：3.75 ng/larva） of chlorfluazuron on ovarioles during ovarian development and oogenesis of common cutworm, Spodoptera litura （F.）. It is a significant pest of cotton, tobacco and miscellaneous vegetables. The LDlo or LD3o was applied topically to the newly-ecdysed fifth-instars of S. litura under laboratory conditions. In controls, on 2nd day of adult emergence, the cell density in germarium was 1636 ± 9.17 nuclei/mm^2. It increased until 3rd day, i.e., 1829 ± 8.87 nuclei/mm^2 and decreased thereafter. In the LDloor LD-3o-treated insects, the patterns of the cell density was the same as in controls but values were significantly （P 〈 0.05） decreased in the LD10- and more in the LDa0-treated females compared with controls. In control, ovaries were normal type and had mature ova with an occasional one or two being absorbed. In LD10-treated females, ovaries had spaces in ovarioles and absorption of ova. In LD30-treated females, besides the spacing and absorption, sometimes only immature （germarium） ova were found.展开更多
文摘The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodoptera litura （F.） are described. Chlorfluazuron was applied topically to newly-ecdysed fifth-instar larvae of S. litura under laboratory conditions. During first day of pupation, spermatids were the highest （3,430 ± 7）, however, elongated spermatocytes with mature sperm were the lowest （292 ± 16） in number in pupal-testis compared with other developing spermatocytes. During last day of pupation, elongated spermatocytes with mature sperm were the highest （3,581 ± 3）, however, spermatogonia were the lowest （86± 4） in number in pupal-testis compared with other developing spermatocytes. The number of spermatogonia, primary and secondary spermatocytes, spermatids and elongated cysts with mature sperm were increased during pupal-developmental days in the controls. However, their numbers were significantly reduced in LD10- and even more significantly reduced in LD30-treated pupal-testis compared with controls. Moreover, eupyrene sperm bundles were not present in pupal-testis. During pupal-developmental days, spermatids were the smallest （4.1 ± 0.9 dm in μm） and secondary spermatocytes were the largest （31.0 ± 1.8 dm in μm） in size compared with other developing spermatocytes. The sizes of the same developing spermatocytes were significantly reduced in LD10-treated and more significantly reduced in LD30-treated pupal-testis of S. litura compared with controls.
文摘This paper describes effects of sublethal-doses of chlorfluazuron on morphology of embryogenesis when LD10 （1.00 ng/larva） or LD30 （3.75 ng/larva） was applied topically to newly-ecdysed fifth-instars of common cutworm, Spodoptera litura F.. Experiments were conducted on eggs of F1 generation laid by subsequent adults under laboratory conditions. Fecundity was significantly reduced by LD10 and more significantly reduced by LD30 compared with untreated females. Number of unfertilized-unhatched-eggs was not significantly affected by the treatments, Fertilized eggs revealed changes in external coloration of eggs. Embryonic development of S. litura was divided into eight embryonic stages. During stage 5 （12-16 h after oviposition）, in LD10-treated-egg, crescent-shaped-embryo was affectedly differentiated. During the same stage, it was seriously affected in LD30-treated-egg. During stage 7 （32-64 h after oviposition）, in LD10-treated-egg, organogenesis was established, but body structures were affectedly developed. In LD30-treated-egg, body structures were more affectedly developed during the same stage. It is concluded that embryonic developmental stages were affected by LD10 and more seriously affected by LD30. The effects of residualchlorfluazuron on embryogenesis are thought to be one of the factors responsible for the reduction in fertility and hatchability caused by sublethal doses of chlorfluazuron in S. litura.
文摘Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD3o： 3.75 ng/larva） of chlorfluazuron on spermatogenesis in the adults of the common cutworm, Spodoptera litura （F.）. Chlorfluazuron was applied topically to the newly-ecdysed fifth-instars ofS. litura under laboratory conditions. The secondary spermatocytes, spermatids, elongated spermatocytes with mature sperm and eupyrene sperm bundles were present in testis of newly emerged, 1 and 2 day-old adults, but gradually decreased in their numbers in the controls. However, the spermatogonia were not present in newly emerged, 1 and 2 day-old adults. Moreover, primary spermatocytes were present （174 ± 4.0） in newly emerged adults, but not found in 1 and 2 day-old adults. In the testes of newly emerged LD10-treated adults, the numbers of eupyrene and apyrene sperm bundles were significantly reduced compared with controls, and even significantly reduced in LD30-treated adults compared with LDlo, however, their ratios were not affected. Moreover, the pattern of spermatogenesis was the same in LD10- and LD30-treated male adults compared with controls. Furthermore, numbers of developing spermatocytes were significantly reduced in the LD10 compared with controls, and even significantly reduced in LD30-treated male adults compared with LD10. In newly emerged adults, the width and length of elongated spermatocytes with mature sperm were significantly reduced in LDlo- and more significantly reduced in LD30-treated compared with controls of S. litura. In vas deferens of untreated pre- and newly emerged adult male, both eupyrene and apyrene sperm bundles were found, however, in treated pre-adult male, only apyrene sperm bundles and in treated newly emerged adult male, fe, w eupyrene and numerous apyrene sperm bundles were found. It is concluded that spermatogenesis was significantly affected by chlorfluazuron.
文摘Chlorfluazuron is an insect growth regulator for controlling the major insect pests in crops. This paper describes the effects of sublethal doses （LD10：1.00 ng/larva; LD30：3.75 ng/larva） of chlorfluazuron on ovarioles during ovarian development and oogenesis of common cutworm, Spodoptera litura （F.）. It is a significant pest of cotton, tobacco and miscellaneous vegetables. The LDlo or LD3o was applied topically to the newly-ecdysed fifth-instars of S. litura under laboratory conditions. In controls, on 2nd day of adult emergence, the cell density in germarium was 1636 ± 9.17 nuclei/mm^2. It increased until 3rd day, i.e., 1829 ± 8.87 nuclei/mm^2 and decreased thereafter. In the LDloor LD-3o-treated insects, the patterns of the cell density was the same as in controls but values were significantly （P 〈 0.05） decreased in the LD10- and more in the LDa0-treated females compared with controls. In control, ovaries were normal type and had mature ova with an occasional one or two being absorbed. In LD10-treated females, ovaries had spaces in ovarioles and absorption of ova. In LD30-treated females, besides the spacing and absorption, sometimes only immature （germarium） ova were found.
