Effect of Sublethal Concentration of Malathion Insecticide on Innate Immune System, Immune Function and Hemocytes of Adult Drosophila melanogaster

Abstract

Invertebrate organisms mostly have innate immune system. Hemocytes are the immune cells of the innate immunity in invertebrates. Our study was designed to observe the effect of malathion insecticide on the innate immune system, immune function and hemocytes of Drosophila melanogaster. A hemocytometer was used for total count of hemocytes which showed a reduced percentage of live cells (from 91.63% to 44.57%) due to the treatment. For differential count, the hemolymph was spread as a smear on a clean grease free slide. It was observed that the plasmatocyte count considerably decreased under the effect of malathion (from 78% to 44.66%). Lamellocytes also showed a decline in their number (from 18.33% to 12.61%). But, a trivial increase (from 3.67% to 3.98%) in crystal cell count was recorded. Our result suggests that malathion has mostly negative effect on hemocytes. This study could help in understanding of insect defense mechanism against such hazardous chemicals. Additionally, the function of human macrophages is analogous to the function of plasmatocytes. Hence, this work could possibly aid us in studying the response of human immune cells against organophosphates like malathion.