| Abstract: | Contact with organophosphorus, carbamate, organochlorine and pyrethroid insecticides caused accelerated water loss from all major parts of the integument of the housefly. The response appeared to be specific in that only insecticides, and not their truly non-toxic analogues, had this effect, specificity being also reflected in resistance and in synergistic and antagonistic responses. As an insecticide dispersed laterally in the integument the effect spread to more distant parts, including the intestinal and tracheal systems, its arrival in the tracheal system coinciding with a reduction in the rate of respiration. It is suggested that this reaction of the integument to contact with insecticides is the primary cause of eventual death. Interference with the water balance in the tracheal system affects the normal exchange of the respiratory gases and thus proper respiratory control, to which the insect reacts with symptoms of excitation and paralyses. Degeneration of vital tissues following the loss of water is probably ultimately responsible for the death of the insect. |
