Blow Flies

Growers of those Asclepiad species that bear flowers producing a smell mimicking rotting carrion, may observe a variety of blow flies to be attracted to the flowers, depending upon their location. Sometimes the flies lay their eggs in the flowers, and these develop into lavae which soon die through lack of food.

Green bottle (0.5 in)
Green bottle 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.

Blue bottle (0.5 in)
Blue bottle larvae feed on a variety of rotting plant and animal material.

Screw worm fly (0.3 in)
The screw worm fly lays its eggs in open wounds and the larvae eat into the flesh, enlarging the wound which then attracts more screw worm flies and blow flies. This serious pest of livestock in South America has been virtually eradicated from the Southern States of the USA by a programme of releasing huge numbers of radiation-sterilised male flies and is a major success for the science of radiation biology.

Black blow fly (0.3 in)
The adult black blow fly sucks blood from livestock and lays its eggs in open wounds.