Abstract: The complex of insect innate immunity is evolved in a long-term for self-defense. Pathogen recognition mediated by different pattern recognition proteins (PRPs) plays a vital role in the first step of activating the immune responses. To date, different PRPs, including peptidoglycan recognition proteins (PGRPs), immunoglobulin, β-1, 3-gulcans binding proteins (βGBPs), C-type lectins and multi-functional apolipoproteins, as well as their functions in the process of recognizing molecular patterns of various insect pathogens, have been identified. To counteract host recognition, however, insect pathogens also have evolved strategies of camouflage and masking to invade insect immune responses and develop diseases or eventually kill the insect hosts. This article mainly dealt with recent advances in the mechanisms of insect immune recognition and immune escape. The former includes the binding targets, protein structures and functions of different PRPs, and the latter mainly focuses on the anti-immune strategies developed through different pathogens. Future studies on insect immunology and the mechanisms of microbial pathogenesis are discussed in some detail. Most importantly, only when the studies on immunity and pathology are well combined, can the dynamic molecular interactions between insect hosts and pathogens be properly understood.

Key words: Insect innate immunity, pattern recognition protein, pathogen associated molecular pattern, insect pathogen, immune escape