Effects of sublethal doses of chlorfluazuron on the testicular biochemical constituents of Spodoptera litura (Lepidoptera: Noctuidae)

Abstract

The effects of sublethal doses (LD₁₀: 1.00 ng/larva; LD₃₀: 3.75 ng/larva) of chlorfluazuron on the amounts of testicular biochemical constituents of the common cutworm, Spodoptera litura (F.) was described. Chlorfluazuron was applied topically to newly ecdysed fifth-instar larvae under laboratory conditions. Sublethal doses of chlorfluazuron significantly reduced the amount of protein with no effect on carbohydrate and lipid. The relative proportion of the amounts of control testicular DNA was: 7.52±0.9 μg/mg at the day before adult emergence> 4.54±0.44 μg/mg at newly emerged adults> 3.52±0.49 μg/mg at 1^st day after adult emergence. Sublethal doses of chlorfluazuron significantly (p < 0.05) reduced the amounts of testicular, seminal vesicular and aedeagular DNA compared with the controls. Similar reduction was observed in RNA as found in DNA. Three peaks in ecdysteroid titres were observed during 80 to 208 h. Compared with the controls, all peaks were reduced in LD₁₀ or LD₃₀ treated testis as follows: 11.5 or 21%; 12 or 22%; 12.5 or 23%, respectively. Sublethal doses of chlorfluazuron reduced the ecdysteroid titres with no effect on its pattern. Sublethal doses of chlorfluazuron reduced the amounts of biochemical testicular constituents during the development of testes in S. litura.

Key words: Chlorfluazuron, ecdysteroid titre, nucleic acid, protein, Spodoptera litura, sublethal doses, testicular biochemical, seminal vesicle, aedeagus.