Immune defense of insects: An overview

In spite of not having any definite immune system, insects show some sort of mechanism related to immunity. Immune response is carried out mainly by cellular and humoral pathways. Insects use melanin, various types of hemocytes such as plasmatocytes, crystal cells for immune responses. These immune mechanisms are regulated by various signaling pathways. Among these toll, NFkβ, intigrin and JAK/STAT pathways are very important. Though cell mediated response is associated with hemocytes and humoral response is associated with anti microbial peptide and hemolymph but there is a relationship among all the pathways.