Although insects lack an adaptive immune system, they do have powerful means of fighting infections. Cellular responses involve phagocytosis of bacteria and encapsulation of parasites. In addition, insects can mount a humoral response against pathogens.

Do insects have innate immunity?

Insects and mammals share an ancient innate immune system comprising both humoral and cellular responses. The insect immune system consists of the fat body, which secretes effector molecules into the hemolymph and several classes of hemocytes, which reside in the hemolymph and of protective border epithelia.

What animals have adaptive immunity?

Primitive jawless vertebrates, such as the lamprey and hagfish, have an adaptive immune system that shows 3 different cell lineages, each sharing a common origin with B cells, αβ T cells, and innate-like γΔ T cells.