Methods for Assessing Exposure of Insects

Like other constituents of ecosystems, insects are exposed to the action of many man-made chemicals, some of which accumulate in live and inanimate parts of the environment. Insects constitute an important group of organisms, because of the diversity of their morphology and physiology, their abundance, economic importance, and numerous effects on human health. Insects seem to display the greatest diversity of biochemical and genetic responses to stress from exposure to exogenous chemicals. For that reason, adequate methods must be developed for qualitative and quantitative determinations of xenobiotics, and detoxication mechanisms in insect tissues must be understood. While some relatively reliable methods have been developed for diagnosing some of these mechanisms (e.g., insect resistance to some pesticides), methods to measure precisely biological responses to exposure need to be improved. This survey attempts to summarise methods commonly used for assessing exposure: (1) Direct determination of xenobiotics at the level of cells and organs; (2) Qualitative and quantitative biochemical changes in some lowmolecular and high-molecular substances; (3) Genetic changes at individual and population levels as indicators of exposure; and (4) Effects of xenobiotics at the population level.