Ultrastructure of two Types of Endocrine Cells in the Midgut Epithelium of Spodoptera Exiqua Hűbner, 1808 (Insecta, Lepidoptera, Noctuidae)

Abstract

Ultrastructure of two Types of Endocrine Cells in the Midgut Epithelium ofSpodoptera ExiquaHűbner, 1808 (Insecta, Lepidoptera, Noctuidae)Midgut epithelium of Lepidoptera consists of four types of cells: columnar, goblet, endocrine and regenerative. Among endocrine cells two types have been distinguished: "open" and "closed". In all five larval instars ofSpodoptera exiqua(Lepidoptera, Noctuidae) only "open" endocrine cells were observed, which means that their apical membranes contact with the midgut lumen and form microvilli like columnar cells of epithelial character. Among them granular and vesicular cells are distinguishable. The number of vesicular endocrine cells increases distinctly in the 5thlarval instar. The structure of endocrine cells in the midgut epithelium ofS. exiquaand their differentiation from the regenerative cells, studied in transmission electron microscope, are described.