Role of eicosanoids in insect immunity: new insights and recent advances

Viruses, bacteria, fungus, protozoans, and different metazoan parasites and parasitoids present a constant threat to insects. Insect immunity has two components: humoral and cell mediated. Humoral immunity can be achieved by various antimicrobial proteins, namely, cecropins, sarcotoxin, defensin, attacin, etc. The cell-mediated immunity comprises various cells having immune functions fostering nodulation, phagocytosis, microaggregation, encapsulation etc. Eicosanoids play a crucial role in insect immunity comparable to other animals. The above-mentioned are signaling molecules derived from polyunsaturated fatty acids and they exert numerous physiological effects, namely, inflammation, immune modulation, and regulation of cellular processes. The review article elucidates various roles of eicosanoids, namely, nodulation reaction, Toll signaling pathway, nitric oxide (NO) generation, Ca