Previous studies have shown that holometabolous insects, such as Lepidoptera, Coleoptera, and Drosophila, produce antimicrobial peptides (AMPs) through the Toll pathway after infection with fungal pathogens, and AMPs in hemimetabolous pea aphids in the order Hemiptera are produced through the JNK pathway after infection with bacterial pathogens (23). This evidence concerns the gene TLR4 and infection.