Cecropins have lytic and antibacterial activity against several Gram-positive and Gram-negative bacteria. Strongly expressed in larval, pupal and adult fat body and hemocytes after injection of bacteria. Maximal expression in the adult involves fat body cells of the head, thorax and abdomen. Induced as part of the humoral response to a bacterial invasion (PubMed:2390977). Transcripts appear within one hour after injection of bacteria into the hemocoel, reach a maximum after 2-6 hours and have almost disappeared after 24 hours (PubMed:2104802). Similar response is seen when flies ingest bacteria present in their food (PubMed:2104802). Belongs to the cecropin family.