Maggots are natures unsung heroes
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Cape Town - While the sight of maggots crawling through decaying food or decomposing roadkill may leaving your stomach turning, many do not know that maggots are actually nature’s unsung heroes.
Maggots, along with bacteria and other insects, are drawn to dead flesh with a strong desire to feed on it and though the idea of them eating through dead flesh may leave you feeling light-headed, maggots actually offer services to detectives and researchers by assisting with investigations of crimes and the healing wounds beyond repair.
Forensic medicine and toxicology PhD researcher at UCT Kyle Kulenkampff said that maggots are important in solving crimes because one of the primary roles that a forensic entomologist performs when aiding a medico-legal investigation is the estimation of post-mortem interval (PMI), that is the period of time that the deceased has been dead for.
“This can be vital to investigations because it can be used to corroborate witness testimonies, aid pathologists in determining the cause of death and aid other ancillary investigations such as toxicology, whose results may be influenced by the period of time the deceased has been dead for.”
“Insects can be used to estimate how long the deceased has been dead for up to several weeks. This is because when something dies it starts to decompose, and as it decomposes the micro-environment that it presents changes as the decomposition progresses. Different species of insects will colonise the corpse at different stages of decomposition. We refer to this as successional infestation of insects. Maggots’ (larvae of flies) growth rate is dependent on the environmental conditions that they are exposed to, mainly temperature.
“Now certain species of flies colonise a corpse by laying eggs on the corpse, within minutes of the death of the deceased. Provided that they, the flies, have access to the corpse one can examine the local successional infestation patterns and the growth of the maggots found on the corpse and can then determine how long the corpse has been exposed to them.
“So, if you know the environmental temperature that the corpse was exposed to and what the species of the maggot is, you can rear the maggot to its next developmental stage and then calculate using the growth charts how long the maggot was on the corpse for. Thus, you can see that fly maggots play a vital role in PMI estimation and can aid in medico-legal investigation. Additionally also bringing closure to the loved ones of the deceased,” said Kulenkampff.
Investigative forensic psychologist Dr Gerard Labuschagne said that forensic science is essential for the performance of a medico-legal investigation in order to find evidence that can be used to solve the crime.
“What happens is that a crime scene expert from the Local Criminal Records Centre (LCRC) will be activated to any crime scene. They are on 24-hour standby like a detective would be. They have to make use of an LCRC for the photographic documentation of a crime scene and the collection of evidence that is then dispatched to the forensic laboratory for analysis.
“There are procedural guidelines for the work of these various members (detectives, crime scene). A detective can request any other forensic expert to attend the scene to assist him, such as ballistics, forensic pathologists, profilers etc. A detective looks for evidence such as murder weapons, eyewitnesses etc, it depends on what kind of case (e.g. murder or fraud) then exhibits are sent to the SAPS Forensic Science Laboratory (FSL) in Pretoria or Cape Town for further analysis provided the evidence given.”
In terms of treating wounds, Kulenkampff said that maggots are used in the debridement of chronic wounds.
“Debridement of chronic wounds refers to the removal of decomposing tissue and disinfection of the wound. This is called maggot debridement therapy (MDT). In this therapy sterile (non-breeding) and disinfected maggots of the species Lucilia sericata, the common green bottle fly, are introduced to the chronic wound because they heavily prefer decomposing or necrotic tissue over healthy tissue, they will eat the decomposing tissue without damaging the healthy tissue. They are also an aerobic organism, needing oxygen to survive, thus they stay on the wound surface. “
“Maggot debridement therapy (MDT) helps remove necrotic tissue from the wound, as well as, prevents infection by inhibiting bacterial growth and biofilm formation. Also they ingest microorganisms that may infect the wound. Overall, what this does is help promote the healing of the wound. If the correct species of maggot is used and the maggots are disinfected before they are introduced to the wound; MDT should have no risks associated with its use,” said Kulenkampff.
He added that it goes without saying that maggots and many other insect species play a vital role in the decomposition of carcasses in the wild. If necrophagous (decomposing flesh-eating) insects were to vanish from our ecosystems animal carcasses would take much longer to decompose.
“In the Western Cape, there are no common large scavengers that can consume the biomass of the carcass. In many cases the carcasses would probably just desiccate and mummify if it were not the necrophagous insect activity. Not only this but flies and maggots are a vital food source to many different animals, which in turn help maintain our ecosystems.”
“On a side note, you may want to look into the commercial applications of maggots. Black soldier flies have been used as a protein source for aquafarming. These maggots are raised on the blood and other by-products that are not sold at an abattoir. The larvae are then used to produce feed for fish that are kept in aquafarms. It’s supposed to be a sustainable means of aquafarming and food production,” said Kulenkampff.