Histopathological and ultrastructure changes in the embryonic development of Schistocerca Gregaria (Forskal) (Orthoptera): Acrididae induced by Lufenuron (CSI) and rice bran extract (waste product)

Abstract

Background: Waste product compound of rice bran and lufenuron are considered safe compounds to the human and to the environment. They can be used to control Schistocerca gregaria. Objective: The aim of the present study is to examine the ultrastructural changes and histopathological alteration in the Schistocerca gregaria embryogenesis induced by selected waste product compound of rice bran (Oryza sativa) and a chitin synthesis inhibitor (lufenuron). Materials and Methods: Histological and ultrastructure study of normal and affected eggs of Schistocerca gregaria were conducted to demonstrate the effects of lufenuron and rice bran extract on the embryogenesis. Cleavages started about 5 hrs post oviposition (pop) and continue to divide until formation of cellular blastodrem by 1 day pop. By 2 days pop germ band is formed, differentiated into ectoderm and mesoderm. At 3 days pop segmentation of germ band into mouthpart and three thoracic segments occur. Antenna was observed at 3 days pop. Fore and midgut were detected by 5 days pop. Hindgut was also observed by 5 days pop. By 4 days pop, eyes and brain appeared. Brain appeared as two ganglionic masses separated by oesophagus, which by 5 days pop appears as 2 large interconnect cerebral lobes enwrapped by neurilemma. Histological section of affected eggs showed great effects on brain, alimentary canals and compound eyes. Results: Ultrastructure study of newly deposited eggs showed that, the chorion consists of several easily distinguishable layers and in 30-hour-old eggs, cleavage nuclei of different shapes could be observed. The nuclei of the blastoderm cell have spindle shape and have condensed chromatin, which attaches to nuclear membrane. Electron micrograph of lufenuron-affected eggs revealed abnormal chorion and cleavage nuclei. In rice bran affected eggs, disintegrated blastoderm that failed to arranged and sever malformed nuclei were seen. Vaculation and lysis of cell components leaving cavities within the ooplasm were detected in both treatments. Conclusion: The tested compounds induced serious changes to the embryos of Schistocerca gregaria as revealed by the histological and ultrastructure studies.