Phospholipase A2 (PLA2) hydrolyzes fatty acids from phospholipids at sn-2 position. Two immune-associated PLA2s are known in Spodoptera exigua. Both are calcium-independent cellular PLA2 (iPLA2A and iPLA2B). These iPLA2s are inducible to immune challenge using different epitopes such as virus, Gram+, Gram- bacteria, and fungi. However, their expression profiles are different between these two iPLA2s. Especially, immune challenge with Gram+ bacteria and fungi significantly up-regulated these iPLA2 expression, suggesting their expression under Toll signal pathway. RNA interferences of Toll or IMD signal components are being investigated.