Maggots! The juvenile forms of flies, are often found in decomposing vegetation, dung and certainly in carrion; as anyone knows on finding forgotten leftovers of dog meals. Flies can help police in investigating unexplained deaths. Flies arrive at a dead body soon after it cools and forensic entomologists can work out the time since death by the succession of types and life cycle stage of insects found on the body. Eggs, larvae and pupal cases (particularly of flies) tell their own part of the story. Fly pupal cases remained in Egyptian mummies and Mexican tombs until discovered by modern archeologists. The carrion fly larvae had feasted on the body, metamorphosed into adult flies which buzzed off to find a gruesome new breeding spot and left the pupal case evidence of their ancient presence.
Fly larva or maggot from a compost heap.
Adult bushflies, the bane of the Australian bush, lay eggs in rich, moist, fresh dung. Larvae hatch, eat the organic debris in the dung and pupate then change into adults which fly off to plague us.
Maggots look just so different to the adult fly. They don't have legs, wings or eyes. They are soft-bodied as they usually live in moist environments of compost heaps, other rotting vegetation, dung pats or freshly dead animals. No wonder they inspire feelings of disgust and loathing as they blindly squirm their way around their squishy home. But they do a great job breaking down organic matter.
Fly larva. Note the absence of legs. Head is at the bottom of photo.
Medicinal Maggots. Yuk! In Europe and the USA, doctors place specially bred, sterilised blowfly maggots on open wounds to clean out the dead tissue while leaving healthy tissue - yes, maggots can tell the difference. An additional benefit is that they secrete anti-bacterial waste products and can be used in medical cases where anti-biotic resistant strains of Staphlycoccus aureus and other streptococcal infections have taken hold. It is thought that the anti-bacterial action is partly caused by changes in pH of the wound as maggots secrete ammonia-based waste products.
To make sure the maggots stay in place, a special cast with a nylon netting top is closely fitted to the maggot-infested wound and an absorbent pad placed on top of the netting to soak up any toxic by-products of maggot-feeding which might lead to tetanus infections. A standard infestation of 10 maggots/cm2 of wound is prescribed. Any qualms the patient may have about maggot therapy are psychological as the only physical sensation is a tickling or nipping feeling in the wound. Positive effects on wounds were seen within 48 hours of starting maggot therapy.
This form of treatment is used in badly-healing leg and foot ulcers of diabetics, bed sores, stab wounds and operation wounds. Understandably, this treatment is considered unconventional among some parts of the medical profession (and presumably patients!) as we associate maggots with filth and disease.