Ultrastructural changes in integument of Tribolium castaneum (Coleoptera: tenebrionidae) induced by chitin synthesis inhibitor (IGR) chlorfluazuron.

Abstract

The present study was planned to investigate the histopathological effects of the chitin synthesis inhibitor chlorfluazuron against the 4 th larval instar of Tribolium castaneum (Coleoptera: Tenebrionidae) under electron microscope level. Toxicity of chlorfluazuron was evaluated under three different temperatures. The sublethal concentrations LC 40 were 2.118, 39.76 and 1.207 ppm, at 20, 29 and 38 • C respectively. Toxicity of this compound increased at relatively high temperature. Ultrastructural studies were carried out on the integument of the prepupae treated as larvae with LC 40 of chlorfluazuron. The treated samples revealed that exuviae of the old cuticle were existed above the new formed integument, some densely-stained material was deposited in endocuticle, procuticle lamellae were disorganized and partially degenerated. Disappearance of moulting fluid. The hypodermis was destructed and detached from endocuticle. Mitochondria were swollen and fusion. Lysis of lysosomelike bodies.

Toxicological and behavioral effects of Chlorfluazuron on pheromone production and perception of Tribolium castaneum (Coleoptera: Tenebrionidae).

“…Ishaaya and Casida, (1974). Also histopathological examination of prepupal instar of T. castaneum, resulting from 4 th larval instar fed on LC 40 of chlorfluazuron revealed detachment of the epidermal cells from the endocuticle (Khaled, 2009) Furthermore, the abnormal adults observed were due to its resistance to metabolic detoxification during the larval and pupal stages. .…”