Greenbottle Fly, (Phaenicia sericata), larvae are scavengers and feed exclusively on rotting carrion. The flies, which feed on nectar, are extremely efficient at locating dead animals, (or humans). Pathologists use the developmental stage of the larvae and pupae on a corpse of unknown provenance to determine the length of time since death. Blow-fly maggots have recently been adopted by some physicians as a treatment for gangrenous wounds, as those of the correct species will only eat dead tissues.