Ultrastructural changes in the digestive tract of Deroceras reticulatum (Müller) induced by a carbamate molluscicides and by metaldehyde

Abstract

Electron microscope investigations reveal different reactions of cells in the digestive tract of Deroceras reticulatum to intoxication with carbamate or metaldehyde molluscicides. All enterocytes are more strongly attacked by the carbamate compound Mesurol than by metaldehyde. The better efficiency of Mesurol is primarily attributed to its severe impact on nuclei, leading to other cell damage and finally to an increased macrophage reaction. Metaldehyde leaves the enterocyte functions more or less intact except for that of mucus cells. It activates mucus extrusion immediately after the onset of intoxication. This mucus serves to dilute the toxin, which passes through the digestive tract and is voided. The severe attack of metaldehyde on the immature mucus cells results in cessation of mucus production, leading to a fatal mucus deficiency in the digestive tract.