Protophormia terraenovae
Encyclopedia
Protophormia terraenovae is commonly called northern blowfly, blue-bottle fly or blue-assed fly. It is distinguished by its deep blue coloration and large size, is an important species throughout the northern hemisphere. This fly is notable for its economic impact as a myiasis
pest of livestock and its antibiotic
benefits in maggot therapy
. Also of interest is P. terraenovae’s importance in forensic investigations: because of their temperature-dependent development and their prominent presence on corpses, the larvae of this species are useful in post-mortem interval (PMI) determination.
family
, was named and first described by French entomologist André Jean Baptiste Robineau-Desvoidy in his 1830 “Essai sur les myodaires.” Its genus
is shared by one other fly, Protophormia atriceps. Both flies are a dark, undusted, metallic blue-green-black. P. terraenovae is differentiated from P. atriceps by its flat face, plumose arista
, and by up to 2 additional pairs of setae along the margin of the scutellum. P. terraenovae’s specific epithet is translated from the Latin
as “of the New World.”
The oldest-known specimens of P. terraenovae pupae were identified by in 1973 within the fossilized skull of a steppe wisent
. The bison skull, estimated to date from the late Eemian period, was excavated from the site of a new sluice
for the Brussels-Rupel Canal
in Zemst, Belgium. The specimens, although approximately 75,000 years old, are identical in form to the pupae of the modern species.
of calliphorids, measures between 7 and 12 mm in length. It is characterized by a black to brown anterior thoracic spiracle
, a black basicosta, brown wing veins, and dark calypters. Upper calypters sprout black setae. While the thorax and abdomen of P. terraenovae can range in color from dark purple to dark green, the head and legs of this fly are black. Postocular setae are short but prominent; the palpi are yellow or dusky brown.
Sexes of the species are easily distinguished by the width of the space between the eyes, the frons
: that of the female is .386 times the width of the head, while the frons of the male is only .140 times the head width. Chaetotaxy, the study of setae arrangement, is also useful for determination of sex—for example, the male lacks the fronto-orbital, lateroclinate setae found in the female. These setae are located just at the edge of the frons, near the upper portion of the complex eyes.
e are tiny and white, with 12 segments. Length varies by larval age, with the first instar
growing up to 2.63 mm and the third, by contrast, as long as 11.87 mm. In the third instar, the last segment is adorned with pointed tubercles, and segment 10 exhibits dorsal spines along its posterior margin. The latter characteristic distinguishes P. terraenovae, 3rd instar, from a similar calliphorid, Phormia regina
.
, Protophormia terraenovae is holometabolous in its development, meaning it experiences dramatic changes from immature to adult. Protophormia terraenovae undergoes three instars, a pupal stage, and finally an adult stage.
First instar larvae obtain a liquid diet from orifices or wounds of a body. The instars that follow digest the body itself. Among the first to colonize, Calliphoridae species are found on the body almost immediately. As eggs hatch into the first larval stage, P. terraenovae begins feeding and increases in size, limited by its chitinous outer cuticle
. As P. terraenovae larvae molt into the second instar, feeding intensifies: with larger and more developed mouthparts, second instars are able to break down tougher body tissues.
The third instar is unique, consisting of several substages. First, the larvae feed until they reach their maximum size. Next, larvae clear their crops. In this prepupal stage, also called the wandering stage, the maggots seek a dry, safe area for pupation. During the pupal stage, the outer cuticle hardens and tans into a dark brown color, gradually darkening with age. Finally, metamorphosis into the adult is completed with the shedding of the pupal casing and the emergence of the fly.
The time of development between instars to pupae to adult differs depending on temperatures. The mean duration of development, at constant pressure and 25°C, between oviposition and hatching is 1.83 days. From first to second instar, approximately 2.92 days pass. About 6.17 days pass between the second and third instar, and 8.0 days between the third instar and the post-feeding stage. The wandering maggot takes around 9.67 days to reach the pupal stage. Lastly, emergence of this blowfly occurs about 15.83 days after pupation. In fluctuating conditions such as those around crime scenes, there is a tendency for development to slow down. Under-approximation of age is therefore a common mistake.
The development of P. terraenovae is inversely related to temperature. Studies at (15, 20, 25, 30, 35)°C were performed, and the minimal duration of development from oviposition
to adult ranges from 9.19 ± .3 days at 35°C, to 37.78 ± 2.96 days at 15°C. The minimum development threshold for total immature development is 8.95°C. The overall thermal constant (K) for P. terraenovae is 240.2 ± 9.3 day-degrees above threshold. The inverse relationship and regression of development from oviposition to pupation resulted in a 9.8°C threshold for the species.
Pupation occurs on or within .5 meters of the decaying body. The duration of the pupal stage is relatively long compared to the rest of development, inactively occupying 43% of P. terraenovae’s total cycle. The third instar larva spends 13% of its cycle in feeding stage and 22% in post-feeding stages.
distribution, meaning the species is found throughout the northern hemisphere. The fly is common in cool regions and, being "the most cold tolerant of all calliphorid species," can withstand extreme temperatures. P. terraenovae can be found as close as 550 miles from the North Pole and is abundantly found in the Arctic.
In North America
, P. terraenovae can be found from Mexico
to Canada
. Appearance of this species is rare and mostly confined to the winter months in warm regions such as Texas
and Florida
. P. terraenovae is a spring or summer species in high latitudes and elevations.
wounds containing necrotic flesh. Various studies have shown that MDT is effective in treating wounds that have failed to heal. Effective MDT species consume necrotic tissue while cleansing the wound. Protophormia terraenovae is among the few blowfly species that fit these criteria. The larvae of most blowflies are necrophagous, meaning they develop in the bodies of dead vertebrates where they consume necrotic tissues. Because the majority of other blowfly larvae consume both necrotic and healthy tissues, P. terraenovae is an important species. P. terraenovae is also known to produce antibiotics during feeding: the secretions of P. terraenovae larvae are effective in fighting infections involving Streptococcus pyogenes
and Streptococcus pneumoniae
.
The main concern with the use of MDT is sepsis
. P. terraenovae is blamed for five reported bloodstream infections. To prevent infection, P. terraenovae maggots must be raised in vitro under sterile conditions. Provided these precautions are taken, the use of P. terraenovae on chronic wounds appears to remain safe and efficient in wound treatment.
Calliphoridae, Protophormia terraenovae causes economically important myiasis in livestock and, occasionally, in humans. It also has an impact on other populations of Diptera
due to the predacious nature of its larvae when competing for necrotic tissue. P. terraenovae larvae have also been known to behave cannibalistically.
Myiasis due to Protophormia terraenovae has been reported in both wild and domestic animals, but it most commonly affects livestock. Species usually oviposit on carrion
, but are capable of oviposition in the wounds of livestock and wild animals. Thus, P. terraenovae acts as a secondary invader in causing myiasis. Commonly referred to as ‘wound strike’, lesions are foul smelling ulcers that are filled with larvae. Animals infected with myiasis may die from toxemia
and septicemia.
In particular, Protophormia terraenovae causes facultative, cutaneous myiasis of cattle, sheep and reindeer in the northern Holarctic region. Larvae feeding on the skin of sheep causes distress to the animal and loss of wool. This skin damage occurs to a lesser extent in horses, goats and pigs. Adults of this species are capable of causing myiasis but are found only in the Palaearctic and Nearctic
regions.
Also of economic significance are manifestations of the species in slaughter-houses and poultry
houses. Populations of P. terraenovae are maintained by refuse and the carcasses of dead animals. Due to their predacious nature, large numbers of this species can populate in the presence of other Dipteran species. Blowfly bred at these locations cause considerable local nuisance and may spread disease to both humans and animals by contaminating meat and foodstuffs.
is the branch of forensic entomology
dealing with the use of arthropod
evidence in criminal investigations. Because they make up the first wave of fauna
to colonize a corpse, blowflies are among the most accurate forensic indicators of time elapsed since death, technically referred to as the post-mortem interval (PMI). This estimation is made by determining the developmental stages of the insects present on a body. Protophormia terraenovae is forensically important because of its extremely specific developmental time. Two methods are used to determine the PMI of a P. terraenovae-infested body. One approach utilizes information about the developmental stages of larvae located on or within the body, and the second utilizes facts about the larval stage as it emerges from the body to pupate.
The first, second, and third instar larvae present on a body are considered to be feeding stages. The first and second molting are characterized by rapid increases in size and generally occur within a certain range of larval length. Because the development of these flies is dependent on temperature, entomologists can use past weather data to estimate the ages of larvae and even pupae discovered on a corpse.
When post-feeding larvae venture away from the body to pupate, as is common for most blowflies, displacement behavior becomes the determining factor of age. When a body is discovered, if the larvae are leaving, it is possible to measure the distance they have traveled and, with knowledge of the species' crawling speed, to calculate when they left the body. Crawling speed is affected by terrain, temperature, and maggot length. These considerations allow forensic entomologists to make precise age estimations.
Another noteworthy forensic consideration is the use of blowfly species, in this case Protophormia terraenovae, in entomotoxicology
. Evidence of drug use can be found in blowflies feeding upon cadavers with post-mortem drugs in their systems. Studies have shown that unlike other species of necrophagous Diptera, blowfly species can indicate the presence of morphine
in the cuticle
during larval growth, and, definitively, in pupa casings. Because puparial cases decay at an extremely slow rate and can be recovered years after the death of an individual, they can become very important to the examination of a corpse.
resulted in the discovery of trace DNA
evidence linked to twenty-six missing women. The heads, hands, and feet of two of the missing women were eventually found. Protophormia terraenovae larvae were prominent on these remains. Forensic entomologists determined developmental rates based on locally collected specimens of P. terraenovae, and with this information, concluded that both women had been exposed for weeks prior to being frozen. The pig farmer and co-owner of the grounds, Robert “Willie” Pickton
, was charged with the murders of all twenty-six women. In December 2007 Pickton was convicted of second-degree murder in the deaths of six women and stands accused of first-degree murder in the deaths of twenty other women.
levels and molting, and adult diapause
with reactions to certain temperatures.
Microlesions were made inside the brain of Protophormia terraenovae to study the diapause factor. Results show that secretory neurons are necessary for entering the reproductive diapause. Other research based on the haemolymph circulation rate suggests that sensory-induced changes can result in a series of gustatory stimulations that shorten the cardiac cycle
of P. terraenovae.
Myiasis
Myiasis is a general term for infection by parasitic fly larvae feeding on the host's necrotic or living tissue. Colloquialisms for myiasis include flystrike, blowfly strike, and fly-blown. In Greek, "myia" means fly....
pest of livestock and its antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
benefits in maggot therapy
Maggot therapy
Maggot therapy is a type of biotherapy involving the intentional introduction of live, disinfected maggots into the non-healing skin and soft tissue wound of a human or animal for the purpose of cleaning out the...
. Also of interest is P. terraenovae’s importance in forensic investigations: because of their temperature-dependent development and their prominent presence on corpses, the larvae of this species are useful in post-mortem interval (PMI) determination.
Taxonomy
Protophormia terraenovae, of the CalliphoridaeBlow-fly
Calliphoridae are insects in the Order Diptera, family Calliphoridae...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, was named and first described by French entomologist André Jean Baptiste Robineau-Desvoidy in his 1830 “Essai sur les myodaires.” Its genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
is shared by one other fly, Protophormia atriceps. Both flies are a dark, undusted, metallic blue-green-black. P. terraenovae is differentiated from P. atriceps by its flat face, plumose arista
Arista (biology)
In insect anatomy the arista is a simple or variously modified apical or subapical bristle, arising from the third antennal segment. It is the evolutionary remains of antennal segments, and may sometimes show signs of segmentation...
, and by up to 2 additional pairs of setae along the margin of the scutellum. P. terraenovae’s specific epithet is translated from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
as “of the New World.”
The oldest-known specimens of P. terraenovae pupae were identified by in 1973 within the fossilized skull of a steppe wisent
Steppe Wisent
The Steppe Bison or steppe wisent was a bison found on steppes throughout Europe, Central Asia, Beringia, and North America during the Quaternary...
. The bison skull, estimated to date from the late Eemian period, was excavated from the site of a new sluice
Sluice
A sluice is a water channel that is controlled at its head by a gate . For example, a millrace is a sluice that channels water toward a water mill...
for the Brussels-Rupel Canal
Brussels-Scheldt Maritime Canal
The Brussels–Scheldt Maritime Canal, also named the Willebroek Canal, is a canal in Belgium linking Brussels with the river Scheldt. The canal was known as the Brussels-Rupel Maritime Canal, prior to the establishment of a direct link with the Scheldt in 1997.The canal is one of the oldest...
in Zemst, Belgium. The specimens, although approximately 75,000 years old, are identical in form to the pupae of the modern species.
Adult
The adult Protophormia terraenovae, one of the larger speciesSpecies
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of calliphorids, measures between 7 and 12 mm in length. It is characterized by a black to brown anterior thoracic spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
, a black basicosta, brown wing veins, and dark calypters. Upper calypters sprout black setae. While the thorax and abdomen of P. terraenovae can range in color from dark purple to dark green, the head and legs of this fly are black. Postocular setae are short but prominent; the palpi are yellow or dusky brown.
Sexes of the species are easily distinguished by the width of the space between the eyes, the frons
Frons
Frons is the term used to describe the frontal area of an insect's head. It covers the upper part of the face above the clypeus and below and between the antennae. It supports the pharyngeal dilator muscles and usually bears an ocellus . The term itself is derived from the Latin frons "forehead"....
: that of the female is .386 times the width of the head, while the frons of the male is only .140 times the head width. Chaetotaxy, the study of setae arrangement, is also useful for determination of sex—for example, the male lacks the fronto-orbital, lateroclinate setae found in the female. These setae are located just at the edge of the frons, near the upper portion of the complex eyes.
Larvae
P. terraenovae larvaLarva
A larva 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...
e are tiny and white, with 12 segments. Length varies by larval age, with the first instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
growing up to 2.63 mm and the third, by contrast, as long as 11.87 mm. In the third instar, the last segment is adorned with pointed tubercles, and segment 10 exhibits dorsal spines along its posterior margin. The latter characteristic distinguishes P. terraenovae, 3rd instar, from a similar calliphorid, Phormia regina
Phormia regina
The species Phormia regina, more commonly known as the black blow fly, belongs to the blow fly family Calliphoridae. Although some authorities merge both the blow fly group and the flesh fly group together in the family Metopiidae, key distinguishable physical traits allow for this...
.
Development
Being of the order DipteraFly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
, Protophormia terraenovae is holometabolous in its development, meaning it experiences dramatic changes from immature to adult. Protophormia terraenovae undergoes three instars, a pupal stage, and finally an adult stage.
First instar larvae obtain a liquid diet from orifices or wounds of a body. The instars that follow digest the body itself. Among the first to colonize, Calliphoridae species are found on the body almost immediately. As eggs hatch into the first larval stage, P. terraenovae begins feeding and increases in size, limited by its chitinous outer cuticle
Cuticle
A cuticle , or cuticula, is a term used for any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticles" are non-homologous; differing in their origin, structure, function, and chemical composition...
. As P. terraenovae larvae molt into the second instar, feeding intensifies: with larger and more developed mouthparts, second instars are able to break down tougher body tissues.
The third instar is unique, consisting of several substages. First, the larvae feed until they reach their maximum size. Next, larvae clear their crops. In this prepupal stage, also called the wandering stage, the maggots seek a dry, safe area for pupation. During the pupal stage, the outer cuticle hardens and tans into a dark brown color, gradually darkening with age. Finally, metamorphosis into the adult is completed with the shedding of the pupal casing and the emergence of the fly.
The time of development between instars to pupae to adult differs depending on temperatures. The mean duration of development, at constant pressure and 25°C, between oviposition and hatching is 1.83 days. From first to second instar, approximately 2.92 days pass. About 6.17 days pass between the second and third instar, and 8.0 days between the third instar and the post-feeding stage. The wandering maggot takes around 9.67 days to reach the pupal stage. Lastly, emergence of this blowfly occurs about 15.83 days after pupation. In fluctuating conditions such as those around crime scenes, there is a tendency for development to slow down. Under-approximation of age is therefore a common mistake.
The development of P. terraenovae is inversely related to temperature. Studies at (15, 20, 25, 30, 35)°C were performed, and the minimal duration of development from oviposition
Oviposition
Oviposition is the process of laying eggs by oviparous animals.Some arthropods, for example, lay their eggs with an organ called the ovipositor.Fish , amphibians, reptiles, birds and monetremata also lay eggs....
to adult ranges from 9.19 ± .3 days at 35°C, to 37.78 ± 2.96 days at 15°C. The minimum development threshold for total immature development is 8.95°C. The overall thermal constant (K) for P. terraenovae is 240.2 ± 9.3 day-degrees above threshold. The inverse relationship and regression of development from oviposition to pupation resulted in a 9.8°C threshold for the species.
Pupation occurs on or within .5 meters of the decaying body. The duration of the pupal stage is relatively long compared to the rest of development, inactively occupying 43% of P. terraenovae’s total cycle. The third instar larva spends 13% of its cycle in feeding stage and 22% in post-feeding stages.
Geographic distribution
Protophormia terraenovae has a HolarcticHolarctic
The Holarctic ecozone refers to the habitats found throughout the northern continents of the world as a whole. This region is divided into the Palearctic, consisting of Northern Africa and all of Eurasia, with the exception of Southeast Asia and the Indian subcontinent, and the Nearctic,...
distribution, meaning the species is found throughout the northern hemisphere. The fly is common in cool regions and, being "the most cold tolerant of all calliphorid species," can withstand extreme temperatures. P. terraenovae can be found as close as 550 miles from the North Pole and is abundantly found in the Arctic.
In North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, P. terraenovae can be found from Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
to Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. Appearance of this species is rare and mostly confined to the winter months in warm regions such as Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
and Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. P. terraenovae is a spring or summer species in high latitudes and elevations.
Medical
Maggot debridement therapy (MDT) is commonly used for the cleansing and disinfecting of chronicChronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
wounds containing necrotic flesh. Various studies have shown that MDT is effective in treating wounds that have failed to heal. Effective MDT species consume necrotic tissue while cleansing the wound. Protophormia terraenovae is among the few blowfly species that fit these criteria. The larvae of most blowflies are necrophagous, meaning they develop in the bodies of dead vertebrates where they consume necrotic tissues. Because the majority of other blowfly larvae consume both necrotic and healthy tissues, P. terraenovae is an important species. P. terraenovae is also known to produce antibiotics during feeding: the secretions of P. terraenovae larvae are effective in fighting infections involving Streptococcus pyogenes
Streptococcus pyogenes
Streptococcus pyogenes is a spherical, Gram-positive bacterium that is the cause of group A streptococcal infections. S. pyogenes displays streptococcal group A antigen on its cell wall. S...
and Streptococcus pneumoniae
Streptococcus pneumoniae
Streptococcus pneumoniae, or pneumococcus, is Gram-positive, alpha-hemolytic, aerotolerant anaerobic member of the genus Streptococcus. A significant human pathogenic bacterium, S...
.
The main concern with the use of MDT is sepsis
Sepsis
Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...
. P. terraenovae is blamed for five reported bloodstream infections. To prevent infection, P. terraenovae maggots must be raised in vitro under sterile conditions. Provided these precautions are taken, the use of P. terraenovae on chronic wounds appears to remain safe and efficient in wound treatment.
Economic
As a species of the blowfly familyFamily
In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...
Calliphoridae, Protophormia terraenovae causes economically important myiasis in livestock and, occasionally, in humans. It also has an impact on other populations of Diptera
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...
due to the predacious nature of its larvae when competing for necrotic tissue. P. terraenovae larvae have also been known to behave cannibalistically.
Myiasis due to Protophormia terraenovae has been reported in both wild and domestic animals, but it most commonly affects livestock. Species usually oviposit on carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...
, but are capable of oviposition in the wounds of livestock and wild animals. Thus, P. terraenovae acts as a secondary invader in causing myiasis. Commonly referred to as ‘wound strike’, lesions are foul smelling ulcers that are filled with larvae. Animals infected with myiasis may die from toxemia
Toxemia
Toxemia may refer to:* A generic term for the presence of toxins in the blood, see Bacteremia* An outdated medical term for Pre-eclampsia...
and septicemia.
In particular, Protophormia terraenovae causes facultative, cutaneous myiasis of cattle, sheep and reindeer in the northern Holarctic region. Larvae feeding on the skin of sheep causes distress to the animal and loss of wool. This skin damage occurs to a lesser extent in horses, goats and pigs. Adults of this species are capable of causing myiasis but are found only in the Palaearctic and Nearctic
Nearctic
The Nearctic is one of the eight terrestrial ecozones dividing the Earth's land surface.The Nearctic ecozone covers most of North America, including Greenland and the highlands of Mexico...
regions.
Also of economic significance are manifestations of the species in slaughter-houses and poultry
Poultry
Poultry are domesticated birds kept by humans for the purpose of producing eggs, meat, and/or feathers. These most typically are members of the superorder Galloanserae , especially the order Galliformes and the family Anatidae , commonly known as "waterfowl"...
houses. Populations of P. terraenovae are maintained by refuse and the carcasses of dead animals. Due to their predacious nature, large numbers of this species can populate in the presence of other Dipteran species. Blowfly bred at these locations cause considerable local nuisance and may spread disease to both humans and animals by contaminating meat and foodstuffs.
Forensic
Medicocriminal entomologyEntomology
Entomology is the scientific study of insects, a branch of arthropodology...
is the branch of forensic entomology
Forensic entomology
Forensic entomology is the application and study of insect and other arthropod biology to criminal matters. It is primarily associated with death investigations; however, it may also be used to detect drugs and poisons, determine the location of an incident, and find the presence and time of the...
dealing with the use of arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
evidence in criminal investigations. Because they make up the first wave of fauna
Fauna
Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...
to colonize a corpse, blowflies are among the most accurate forensic indicators of time elapsed since death, technically referred to as the post-mortem interval (PMI). This estimation is made by determining the developmental stages of the insects present on a body. Protophormia terraenovae is forensically important because of its extremely specific developmental time. Two methods are used to determine the PMI of a P. terraenovae-infested body. One approach utilizes information about the developmental stages of larvae located on or within the body, and the second utilizes facts about the larval stage as it emerges from the body to pupate.
The first, second, and third instar larvae present on a body are considered to be feeding stages. The first and second molting are characterized by rapid increases in size and generally occur within a certain range of larval length. Because the development of these flies is dependent on temperature, entomologists can use past weather data to estimate the ages of larvae and even pupae discovered on a corpse.
When post-feeding larvae venture away from the body to pupate, as is common for most blowflies, displacement behavior becomes the determining factor of age. When a body is discovered, if the larvae are leaving, it is possible to measure the distance they have traveled and, with knowledge of the species' crawling speed, to calculate when they left the body. Crawling speed is affected by terrain, temperature, and maggot length. These considerations allow forensic entomologists to make precise age estimations.
Another noteworthy forensic consideration is the use of blowfly species, in this case Protophormia terraenovae, in entomotoxicology
Entomotoxicology
In forensic entomology, entomotoxicology is the analysis of toxins in arthropods that feed on carrion. Using arthropods in a corpse or at a crime scene, investigators can determine whether toxins were present in a body at the time of death...
. Evidence of drug use can be found in blowflies feeding upon cadavers with post-mortem drugs in their systems. Studies have shown that unlike other species of necrophagous Diptera, blowfly species can indicate the presence of morphine
Morphine
Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...
in the cuticle
Cuticle
A cuticle , or cuticula, is a term used for any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticles" are non-homologous; differing in their origin, structure, function, and chemical composition...
during larval growth, and, definitively, in pupa casings. Because puparial cases decay at an extremely slow rate and can be recovered years after the death of an individual, they can become very important to the examination of a corpse.
The "Pig Farm Case"
In 2007, entomological evidence was used in the infamous “Pig Farm Case”. An eighteen-month-long search of several acres of farmland and property in British ColumbiaBritish Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
resulted in the discovery of trace DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
evidence linked to twenty-six missing women. The heads, hands, and feet of two of the missing women were eventually found. Protophormia terraenovae larvae were prominent on these remains. Forensic entomologists determined developmental rates based on locally collected specimens of P. terraenovae, and with this information, concluded that both women had been exposed for weeks prior to being frozen. The pig farmer and co-owner of the grounds, Robert “Willie” Pickton
Robert Pickton
Robert William "Willie" Pickton of Port Coquitlam, British Columbia, Canada is a former pig farmer and serial killer convicted of the second-degree murders of six women. He is also charged in the deaths of an additional twenty women, many of them prostitutes and drug users from Vancouver's...
, was charged with the murders of all twenty-six women. In December 2007 Pickton was convicted of second-degree murder in the deaths of six women and stands accused of first-degree murder in the deaths of twenty other women.
Current and future research
Investigation of the species is still ongoing: specifically, researchers are examining PMI and ADH/ADD for P. terraenovae, ecdysteroidEcdysteroid
Ecdysteroids are insect moulting and sex hormones which include ecdysone and its homologues such as 20-hydroxyecdysone. Ecdysteroids also occur in other invertebrates where they can play a different role. They also appear in many plants mostly as a protection agents against herbivore insects...
levels and molting, and adult diapause
Diapause
Diapause is the delay in development in response to regularly and recurring periods of adverse environmental conditions. It is considered to be a physiological state of dormancy with very specific initiating and inhibiting conditions...
with reactions to certain temperatures.
Microlesions were made inside the brain of Protophormia terraenovae to study the diapause factor. Results show that secretory neurons are necessary for entering the reproductive diapause. Other research based on the haemolymph circulation rate suggests that sensory-induced changes can result in a series of gustatory stimulations that shorten the cardiac cycle
Cardiac cycle
The cardiac cycle is a term referring to all or any of the events related to the flow or blood pressure that occurs from the beginning of one heartbeat to the beginning of the next. The frequency of the cardiac cycle is described by the heart rate. Each beat of the heart involves five major stages...
of P. terraenovae.