Sometimes, a drop of cà cuống, which is the essence of a giant water bug, Lethocerus indicus, is added to the nước chấm for extra flavor, although this ingredient is scarce and quite expensive.
While this is most widely known in mantises, similarly modified legs can be found in some crustaceans (e.g., mantis shrimp), and various insect families, such as Mantispidae, Belostomatidae, Nepidae, and Naucoridae (all members of these groups have raptorial forelegs).