Comparative larval anatomy of the digestive system of three Calliphoridae (Diptera) species that cause different types of myiasis

third instar larvae of three Calliphoridae species: Protocalliphora azurea, an obligate agent of sanguinivorous myiasis in passerine bird nestlings; Cordylobia anthropophaga, an obligate agent of subcutaneous myiasis in mammals; and Lucilia sericata, a facultative agent of traumatic myiasis in mammals. The three species are relatively uniform in the internal anatomy of their digestive organs, although they differ in the shape and size of the salivary glands —a main source of larval antigens—, which are considerably smaller in P. azurea. Moreover, the three species differ from the larvae of Oestridae, a close family that exclusively includes obligate myiasis-causing species, inthe presence of gastric caeca and a crop, which shows a remarkable storage capacity in L. sericata. The observed differences are discussed from a functional perspective and in relation to the type of myiasis caused.