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Effects of sublethal concentrations of the chitin synthesis inhibitor, hexaflumuron, on the development and hemolymph physiology of the cutworm, Spodoptera litura.

Zhu Q, He Y, Yao J, Liu Y, Tao L, Huang Q - J. Insect Sci. (2012)

Bottom Line: Few individuals from 0.5 and 1.2 µg mL(-1)concentrations could develop to the 6(th) instar, while the pupae emerging from the 0.1 µg mL(-1)concentrations did not exceed 16% of the number of the initial larvae.The content of glyceride in hemolymph was significantly higher at 24 hours post-treatment, but gradually returned to normal levels at 96 hours post-treatment as compared with the control.The results suggested that sublethal concentrations of hexaflumuron reduced S. litura larval survival and interfered with hemolymph physiological balances.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai, China. flower3377@163.com

ABSTRACT
The effects of sublethal concentrations 0.1, 0.5, and 1.2 µg mL(-1)of the chitin synthesis inhibitor, hexaflumuron, on larval growth and development, the count and proportion of hemocytes, and carbohydrate content (trehalose and glyceride) in hemolymph were investigated in the cutworm, Spodoptera litura (Fabricious) (Lepidoptera: Noctuidae). When 3(rd) instar larvae were subjected to the sublethal concentrations, there were dose-dependent effects on larval weight and length of each instar larvae, percent pupation and the duration of development. Most of the larvae died during the molting process at all concentrations. Few individuals from 0.5 and 1.2 µg mL(-1)concentrations could develop to the 6(th) instar, while the pupae emerging from the 0.1 µg mL(-1)concentrations did not exceed 16% of the number of the initial larvae. In 5(th)instar S. litura, the total number of hemocytes was significantly increased at 24 hours post-treatment, whereas the proliferation of hemocytes was inhibited, plasmatocyte pseudopodia contracted, and granulocyte expanded at 96 hours post-treatment. The increases of plasmatocyte count and the decreases of granulocyte count were dose-dependent. The longer treatment time of the sublethal concentrations increased the content of total carbohydrate and trehalose in hematoplasma, and was dose-dependent in hemocytes. The content of glyceride in hemolymph was significantly higher at 24 hours post-treatment, but gradually returned to normal levels at 96 hours post-treatment as compared with the control. The results suggested that sublethal concentrations of hexaflumuron reduced S. litura larval survival and interfered with hemolymph physiological balances.

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Related in: MedlinePlus

Survival regulation and subsequent development of 3rd instar larvae after continuously fed with 0.1, 0.5, and 1.2 µg mL-1 hexaflumuron—dipped cabbage leaves. ( 3rd instar, 4thinstar, 5thinstar, 6thinstar, * pupae) High quality figures are available online.
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f01_01: Survival regulation and subsequent development of 3rd instar larvae after continuously fed with 0.1, 0.5, and 1.2 µg mL-1 hexaflumuron—dipped cabbage leaves. ( 3rd instar, 4thinstar, 5thinstar, 6thinstar, * pupae) High quality figures are available online.

Mentions: Regression equation of toxicity of hexaflumuron against the 2nd instar S. litura at 72 hours was determined as y = 0.415 + 1.335x (χ2 = 0.968), and the lethal concentrations of LC20, LC50, and LC70 were estimated as 0.1 ± 0.014, 0.5 ± 0.063, and 1.2 ± 0.108 µg mL-1, respectively. After continuous feeding with treated leaves, sustained and cumulative sublethal toxicities of hexaflumuron were seen on the survival of 3rd instar S. litura and their subsequent development. As shown in Figure 1, at the concentrations of 0.5 and 1.2 µg mL-1, the survival rate of 3rd instar S. litura gradually decreased with the increase in treatment time. Most larvae died during the molting process after they developed to the 4th instar, and a few individuals developed to the 6th instar and then died, while most larvae fed with 0.1 µg mL-1 hexaflumuron were still alive with a survival rate of 16 percent by 24 days post—treatment when the surviving individuals developed into the pupae.


Effects of sublethal concentrations of the chitin synthesis inhibitor, hexaflumuron, on the development and hemolymph physiology of the cutworm, Spodoptera litura.

Zhu Q, He Y, Yao J, Liu Y, Tao L, Huang Q - J. Insect Sci. (2012)

Survival regulation and subsequent development of 3rd instar larvae after continuously fed with 0.1, 0.5, and 1.2 µg mL-1 hexaflumuron—dipped cabbage leaves. ( 3rd instar, 4thinstar, 5thinstar, 6thinstar, * pupae) High quality figures are available online.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472920&req=5

f01_01: Survival regulation and subsequent development of 3rd instar larvae after continuously fed with 0.1, 0.5, and 1.2 µg mL-1 hexaflumuron—dipped cabbage leaves. ( 3rd instar, 4thinstar, 5thinstar, 6thinstar, * pupae) High quality figures are available online.
Mentions: Regression equation of toxicity of hexaflumuron against the 2nd instar S. litura at 72 hours was determined as y = 0.415 + 1.335x (χ2 = 0.968), and the lethal concentrations of LC20, LC50, and LC70 were estimated as 0.1 ± 0.014, 0.5 ± 0.063, and 1.2 ± 0.108 µg mL-1, respectively. After continuous feeding with treated leaves, sustained and cumulative sublethal toxicities of hexaflumuron were seen on the survival of 3rd instar S. litura and their subsequent development. As shown in Figure 1, at the concentrations of 0.5 and 1.2 µg mL-1, the survival rate of 3rd instar S. litura gradually decreased with the increase in treatment time. Most larvae died during the molting process after they developed to the 4th instar, and a few individuals developed to the 6th instar and then died, while most larvae fed with 0.1 µg mL-1 hexaflumuron were still alive with a survival rate of 16 percent by 24 days post—treatment when the surviving individuals developed into the pupae.

Bottom Line: Few individuals from 0.5 and 1.2 µg mL(-1)concentrations could develop to the 6(th) instar, while the pupae emerging from the 0.1 µg mL(-1)concentrations did not exceed 16% of the number of the initial larvae.The content of glyceride in hemolymph was significantly higher at 24 hours post-treatment, but gradually returned to normal levels at 96 hours post-treatment as compared with the control.The results suggested that sublethal concentrations of hexaflumuron reduced S. litura larval survival and interfered with hemolymph physiological balances.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai, China. flower3377@163.com

ABSTRACT
The effects of sublethal concentrations 0.1, 0.5, and 1.2 µg mL(-1)of the chitin synthesis inhibitor, hexaflumuron, on larval growth and development, the count and proportion of hemocytes, and carbohydrate content (trehalose and glyceride) in hemolymph were investigated in the cutworm, Spodoptera litura (Fabricious) (Lepidoptera: Noctuidae). When 3(rd) instar larvae were subjected to the sublethal concentrations, there were dose-dependent effects on larval weight and length of each instar larvae, percent pupation and the duration of development. Most of the larvae died during the molting process at all concentrations. Few individuals from 0.5 and 1.2 µg mL(-1)concentrations could develop to the 6(th) instar, while the pupae emerging from the 0.1 µg mL(-1)concentrations did not exceed 16% of the number of the initial larvae. In 5(th)instar S. litura, the total number of hemocytes was significantly increased at 24 hours post-treatment, whereas the proliferation of hemocytes was inhibited, plasmatocyte pseudopodia contracted, and granulocyte expanded at 96 hours post-treatment. The increases of plasmatocyte count and the decreases of granulocyte count were dose-dependent. The longer treatment time of the sublethal concentrations increased the content of total carbohydrate and trehalose in hematoplasma, and was dose-dependent in hemocytes. The content of glyceride in hemolymph was significantly higher at 24 hours post-treatment, but gradually returned to normal levels at 96 hours post-treatment as compared with the control. The results suggested that sublethal concentrations of hexaflumuron reduced S. litura larval survival and interfered with hemolymph physiological balances.

Show MeSH
Related in: MedlinePlus