Basic Methods to Evaluate Humoral Immunity Processes in Lepidoptera Larvae

Even though insects lack an adaptive immune system, they can survive in environments with many potentially pathogenic invaders. Insects challenge infections by innate immunity defense mechanisms. Among them hemolymph humoral components cooperate to perform melanization (humoral encapsulation) and bacterial clearance. Investigating these two processes is fundamental to understand and check the insect physiological condition either normal or altered by infections or environmental changes. Many experimental protocols to investigate humoral defenses in insects are present in the literature, but discrepancies between them often exist. Such discrepancies are mostly due to the different biology of animal models and to the nature of experimental approach. Here we described less time-consuming and cheaper protocols used to test the activity of both constituent and inducible humoral components present in the hemolymph of insect larvae.