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A maggot is the
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
of a
fly (order
Diptera); it is applied in particular to the larvae of
Brachycera flies, such as
houseflies,
cheese flies, and
blowflies, rather than larvae of the
Nematocera, such as
mosquito
Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
es and
crane flies.
Entomology
"Maggot" is not a technical term and should not be taken as such; in many standard textbooks of
entomology, it does not appear in the index at all.
In many non-technical texts, the term is used for insect
larvae in general. Other sources have coined their own definitions; for example: "The term applies to a grub when all trace of limbs has disappeared" and "Applied to the footless larvae of Diptera".
[Smith, John. B]
Explanation of terms used in entomology
Brooklyn Entomological Society, 1906. Additionally, in ''Flies: The Natural History and Diversity of Diptera'', the author claims maggots "are larvae of higher Brachycera (
Cyclorrhapha)."
Maggot-like fly larvae are of significance in
ecology
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overl ...
and
medicine
Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pr ...
; among other roles, various species are prominent in recycling
carrion and garbage, attacking
crops and
foodstuffs, spreading microbial infections, and causing
myiasis
Myiasis is the parasitic infestation of the body of a live animal by fly larvae (maggots) which grow inside the host while feeding on its tissue. Although flies are most commonly attracted to open wounds and urine- or feces-soaked fur, some spe ...
. Maggots are also particularly important in
forensic entomology
Forensic entomology is the scientific study of the colonization of a dead body by arthropods. This includes the study of insect types commonly associated with cadavers, their respective life cycles, their ecological presences in a given environme ...
because their development can help determine the time of death, particularly maggots in the
Calliphoridae
The Calliphoridae (commonly known as blow flies, blow-flies, carrion flies, bluebottles, greenbottles, or cluster flies) are a family of insects in the order Diptera, with almost 1,900 known species. The maggot larvae, often used as fishing ba ...
family.
Uses
Fishing
Anglers use maggots usually commercially supplied to catch non-predatory fish.
Maggots are the most popular
bait for anglers in
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
. Anglers throw handfuls into the "swim" they are targeting, attracting the fish to the area. The anglers then use the largest or most attractive maggots on the hook, hoping to be irresistible to the fish. Commercial maggot breeders from the
UK sell their maggots to tackle dealers throughout the
E.U. and
North America.
In North America, maggots have been used primarily as
ice fishing bait; recently, however, anglers have started using them year-round.
Medical treatment
Live maggots of certain species of flies have been used since antiquity for wound
debridement
Debridement is the medical removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue. Removal may be surgical, mechanical, chemical, autolytic (self-digestion), and by maggot therapy.
In p ...
. (Use of the wrong species would invite
pathological
Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in th ...
myiasis
Myiasis is the parasitic infestation of the body of a live animal by fly larvae (maggots) which grow inside the host while feeding on its tissue. Although flies are most commonly attracted to open wounds and urine- or feces-soaked fur, some spe ...
.) In controlled and sterile settings overseen by
medical practitioners,
maggot therapy
Maggot therapy (also known as larval therapy) is a type of biotherapy involving the introduction of live, disinfected maggots (fly larvae) into non-healing skin and soft-tissue wounds of a human or other animal for the purpose of cleaning out th ...
introduces live,
disinfect
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than ste ...
ed maggots into non-healing skin or soft wounds of a human or animal. The only maggots cleared for marketing in the United States are larvae of
calliphorid flies of the species ''
Lucilia sericata''. This species of maggots is most widely used in the world as well but it is unclear whether it is the only species cleared for marketing outside of the United States. They feed on the dead or
necrotic
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...
tissue, leaving sound tissue largely unharmed. Studies have also shown that maggots kill bacteria. Three midgut lysozymes of ''L. sericata'' have antibacterial effects in maggot debridement therapy. The study demonstrated that the majority of
gram-positive bacteria were destroyed in vivo within the particular section of the ''L. sericata'' midgut where lysozymes are produced. During the passage through the intestine of the maggots, the ability of bacteria to survive drastically decreased, implying the antibacterial action of the three midgut lysozymes. As of 2008, maggot therapy was being used in around 1,000 medical centers in Europe and over 300 medical centers in the United States.
Forensic science
The presence and development of maggots on a
corpse
A cadaver or corpse is a dead human body that is used by medical students, physicians and other scientists to study anatomy, identify disease sites, determine causes of death, and provide tissue to repair a defect in a living human being. Stud ...
are useful in the estimation of time elapsed since death. Depending on the species and the conditions, maggots may be observed on a body within 24 hours. The eggs are laid directly on the food source, and when the eggs hatch, the maggots move towards their preferred conditions and begin to feed. By studying the insects present at a crime scene,
forensic entomologists can determine the approximate time of death. Insects are usually useful after a
post-mortem interval
The post-mortem interval (PMI) is the time that has elapsed since an individual's death. When the time of death is not known, the interval may be estimated, and so an approximate time of death established. Postmortem interval estimations can ra ...
(PMI) of approximately 25–80 hours, depending on ambient conditions. After this interval, this method becomes less reliable. Blow flies are often used in forensic entomology to determine PMI because of their
oviposition on carrion and corpses. The black blowfly, ''
Phormia regina
''Phormia regina'', the black blow fly, belongs to the blow fly family Calliphoridae and was first described by Johann Wilhelm Meigen.
The black blow fly's wings are specialized with a sharp bend. These flies are also have well-developed calypt ...
(P. regina),'' is extremely widespread across the US and often the earliest species to oviposit on a corpse, making it especially important to forensic science.
[Catts, E P; Goff, M L (January 1992). "Forensic Entomology in Criminal Investigations". ''Annual Review of Entomology''. 37 (1): 253–272. doi:10.1146/annurev.en.37.010192.001345. ]PMID
PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine (NLM) at the National Institutes of Health maintain the ...
1539937.
Behaviours
As with
flea
Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...
s and
tick
Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
s, maggots can be a threat to household pets and
livestock
Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animal ...
, especially
sheep
Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to domesticated ...
. Flies
reproduce
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual org ...
rapidly in the summer months, and maggots can come in large numbers, creating a maggot infestation and a high risk of
myiasis
Myiasis is the parasitic infestation of the body of a live animal by fly larvae (maggots) which grow inside the host while feeding on its tissue. Although flies are most commonly attracted to open wounds and urine- or feces-soaked fur, some spe ...
(a maggot infestation of living tissue) in sheep and other animals. Humans are not immune to the feeding habits of maggots and can also contract myiasis. Interaction between humans and maggots usually occurs near
garbage can
A waste container, also known as a dustbin, garbage can, and trash can is a type of container that is usually made out of metal or plastic. The words "rubbish", "basket" and "bin" are more common in British English usage; "trash" and "can" a ...
s, dead animals, rotten food and other breeding grounds for maggots.
When maggots turn into adult flies and start the life cycle over, numbers will
grow exponentially if unchecked, but disease, natural predators and parasites keep the population under control. Sealing
garbage and using a
garbage disposal
A garbage disposal unit (also known as a waste disposal unit, garbage disposer, garburator etc.) is a device, usually electrically powered, installed under a kitchen sink between the sink's drain and the trap. The disposal unit shreds food w ...
or freezing rotting leftovers until waste collection day helps prevent infestation. Introducing an environmental control, such as
Hister beetles, can also help reduce maggot populations.
See also
*
Annelids
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecolog ...
*
Caterpillars
Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths).
As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Symp ...
*
Polychaete
Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made ...
*
Worm
Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always).
Worms vary in size from microscopic to over in length for marine polychaete wo ...
*
Maggot farming
References
External links
* {{DMOZ, Science/Biology/Flora_and_Fauna/Animalia/Arthropoda/Insecta/Diptera, ''Diptera''
Fly biology
Insect developmental biology
Larvae
Coprophagous insects
Insects in culture