Cynomya cadaverina
Encyclopedia
Cynomya cadaverina, also known as the shiny blue bottle fly, is a member of the family Calliphoridae, which includes both blow flies, as well as bottle flies. In recent years, this family has become a forensically important facet in many medicocriminal investigations in the growing field of forensic entomology
. C. cadaverina is specifically important in determining a post-mortem interval as well as other important factors.
. Its name is derived from the Latin
word cadaverina meaning ‘flies that feed on dead bodies.’ This species is a member of the order Diptera
and the diverse family Calliphoridae.
. This species is known for having a shiny metallic blue abdomen
for which it is named. It has a dark blue or black thorax
and has distinctive darker blue stripes present on the dorsum behind its head. Along with these other characteristics, C. cadaverina also has white calypters, a bare stem vein and a parafacial
with a ground color ranging from black to reddish brown with a yellow covering.
in the highest numbers in the spring and fall months. In most cases, they overwinter
as adults and may enter into houses during that time.
, pupa
and imago
, or adult. C. cadaverina typically has around 17 generations of offspring per year with 25 to 50 eggs per generation if the right conditions are present. Temperature can have an extreme impact on development. If the temperature gets above or below a certain temperature it can cause all development of the fly to stop. In general, the warmer it is, the faster the lifecycle will go. While if it is colder, the lifecycle may take longer than usual. This has to be taken into account when estimating the postmortem interval.
Adults of C. cadaverina lay their eggs in open wounds or natural body openings on carrion typically in small clusters or scattered singly. Southwestern Entomologist, 2003, Volume 1, Issue 1, Pg. 41 The eggs usually hatch out within 24 to 72 hours depending on the season. The eggs will then hatch into larvae that will go through three instars (stages). Each one of these stages is separated by a molt. During a molt, the larvae shed its outer layer in order to accommodate for new growth that comes with increased consumption of food needed for energy stores. The first instar typically lasts for approximately 20 hours while the second instar lasts for 16 hours followed by the third instar for 72 hours. After the larvae have completed their development and stored as much energy as possible they disperse to a safe area to complete their next stage, the pupal stage. This stage lasts for about 9 days before the fly finally emerges as an adult. The total lifecycle of C. cadaverina can take anywhere from 17–19 days depending on the temperature.
. This means the insects go through waves of succession. Using this information as well as the lifecycle of the insect in question it can be used to estimate the PMI. This depends on what stage of development the insect is in as well as the weather in recent months among other factors. Specifically with C. cadaverina they tend to be attracted to fairly advanced stages of decomposition while rarely being found on fresh carrion. They also tend to be in the second wave of succession usually showing up after Lucilia spp. and Calliphora spp.
is the infestation of living or necrotic tissue in a living host by fly larvae. Some flies may just lay their eggs in a festering wound while other may infest unwounded tissue. C. cadaverina has occasionally been found in cases of myiasis but is not a fly that is regularly found. Myiasis is fairly uncommon in the United States but tends to be very common in third world countries and can create a major problem with livestock causing severe economic losses. Myiasis is different from maggot therapy
in which physicians purposely use larvae of flies that feed on necrotic tissue in order to clean up a wound and aid healing. Maggot therapy can clean up a wound that has been festering for months very quickly.
analysis in fly larvae. In cases where larvae have fed on human tissue, these larvae are collected and then the gut is dissected out. The mitochondrial DNA from the gut is analyzed and can lead to the identification of the corpse the maggot
was feeding on as well as the species of the maggot itself. This information could be critical if the body was too decomposed to lead to identification or in other situations where identification would be near to impossible. Research concerning mitochondrial DNA analysis is currently being conducted on C. cadaverina in order to aid in investigations.
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...
. C. cadaverina is specifically important in determining a post-mortem interval as well as other important factors.
Taxonomy
Cynomya cadaverina was first described in 1830 by the French entomologist Jean-Baptiste Robineau-DesvoidyJean-Baptiste Robineau-Desvoidy
André Jean Baptiste Robineau-Desvoidy was a French physician and entomologist specialising in the study of Diptera and to some extent of the Coleoptera .-Achievements:...
. Its name is derived 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...
word cadaverina meaning ‘flies that feed on dead bodies.’ This species is a member of the order 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...
and the diverse family Calliphoridae.
Description
C. cadaverina is a fairly large species ranging anywhere from 9-14 millimeters long and has many characteristics that are common to its family, Calliphoridae. These characteristics include their metallic color, having bristles on their meron as well as having plumose aristaArista (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...
. This species is known for having a shiny metallic blue abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
for which it is named. It has a dark blue or black thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
and has distinctive darker blue stripes present on the dorsum behind its head. Along with these other characteristics, C. cadaverina also has white calypters, a bare stem vein and a parafacial
Parafacial
In Dipteran, the parafacial or parafacialia is the area between ptilinal fissure and the compound eye....
with a ground color ranging from black to reddish brown with a yellow covering.
Distribution
Cynomya cadaverina is known to range throughout the Neartic region with it being found mostly in southern Canada but also in the northern United States. Despite their normal location, they have also been found in states as far south as Florida and Texas. This species is known as a cool weather species and colonizes carrionCarrion
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...
in the highest numbers in the spring and fall months. In most cases, they overwinter
Overwinter
To overwinter is to pass through or wait out the winter season, or to pass through that period of the year when “winter” conditions make normal activity or even survival difficult or near impossible...
as adults and may enter into houses during that time.
Life cycle and development
Members of the order Diptera have a holometabolous lifecycle meaning they go through four life stages: egg, 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...
, pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
and imago
Imago
In biology, the imago is the last stage of development of an insect, after the last ecdysis of an incomplete metamorphosis, or after emergence from the pupa where the metamorphosis is complete...
, or adult. C. cadaverina typically has around 17 generations of offspring per year with 25 to 50 eggs per generation if the right conditions are present. Temperature can have an extreme impact on development. If the temperature gets above or below a certain temperature it can cause all development of the fly to stop. In general, the warmer it is, the faster the lifecycle will go. While if it is colder, the lifecycle may take longer than usual. This has to be taken into account when estimating the postmortem interval.
Adults of C. cadaverina lay their eggs in open wounds or natural body openings on carrion typically in small clusters or scattered singly. Southwestern Entomologist, 2003, Volume 1, Issue 1, Pg. 41 The eggs usually hatch out within 24 to 72 hours depending on the season. The eggs will then hatch into larvae that will go through three instars (stages). Each one of these stages is separated by a molt. During a molt, the larvae shed its outer layer in order to accommodate for new growth that comes with increased consumption of food needed for energy stores. The first instar typically lasts for approximately 20 hours while the second instar lasts for 16 hours followed by the third instar for 72 hours. After the larvae have completed their development and stored as much energy as possible they disperse to a safe area to complete their next stage, the pupal stage. This stage lasts for about 9 days before the fly finally emerges as an adult. The total lifecycle of C. cadaverina can take anywhere from 17–19 days depending on the temperature.
Post-mortem interval estimation
PMI estimation is used to figure out how much time has elapsed since a person died by using insects to help estimate this interval. Depending on the species of insect, some are attracted to fresh corpses while others are only attracted to the putrid and advanced stages of decompositionDecomposition
Decomposition is the process by which organic material is broken down into simpler forms of matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death...
. This means the insects go through waves of succession. Using this information as well as the lifecycle of the insect in question it can be used to estimate the PMI. This depends on what stage of development the insect is in as well as the weather in recent months among other factors. Specifically with C. cadaverina they tend to be attracted to fairly advanced stages of decomposition while rarely being found on fresh carrion. They also tend to be in the second wave of succession usually showing up after Lucilia spp. and Calliphora spp.
Calliphora
Calliphora is the type genus of blow flies, the family Calliphoridae.-Species in the genus Calliphora:...
Myiasis and maggot therapy
MyiasisMyiasis
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....
is the infestation of living or necrotic tissue in a living host by fly larvae. Some flies may just lay their eggs in a festering wound while other may infest unwounded tissue. C. cadaverina has occasionally been found in cases of myiasis but is not a fly that is regularly found. Myiasis is fairly uncommon in the United States but tends to be very common in third world countries and can create a major problem with livestock causing severe economic losses. Myiasis is different from 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...
in which physicians purposely use larvae of flies that feed on necrotic tissue in order to clean up a wound and aid healing. Maggot therapy can clean up a wound that has been festering for months very quickly.
Mitochondrial DNA analysis
In recent years, there have been numerous research projects on the topic of mitochondrial DNAMitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
analysis in fly larvae. In cases where larvae have fed on human tissue, these larvae are collected and then the gut is dissected out. The mitochondrial DNA from the gut is analyzed and can lead to the identification of the corpse the maggot
Maggot
In everyday speech the word maggot means the larva of a fly ; it is applied in particular to the larvae of Brachyceran flies, such as houseflies, cheese flies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and Crane flies...
was feeding on as well as the species of the maggot itself. This information could be critical if the body was too decomposed to lead to identification or in other situations where identification would be near to impossible. Research concerning mitochondrial DNA analysis is currently being conducted on C. cadaverina in order to aid in investigations.
Disease transmission
Cynomya cadaverina has been found to demonstrate communicative behavior via clustering and aggregation. It has been described by the U.S. Food and Drug Administration as being a part of the "filthy fly" category as it tends to breed in excrement and thrives in filthy habitats. This fly can also pose a health hazard due to the transmission of enteric pathogens that can lead to foodborne diseases in humans.Future research
Further research is being conducted on Cynomya cadaverina to gain more information on its lifecycle as well as its behavior in order to better pinpoint time of death with postmortem interval estimation. This information will further aid forensic entomologists as well as investigators in solving medicocriminal investigations. Also, continued research on mitochondrial DNA analysis will be able to provide more identifications in cases where identification may have seemed impossible. Although Cynomya cadaverina is not as forensically or medically important as some of the other species of fly it can still be a powerful tool in investigations as well as aid in maggot therapy.External links
- Bugguide.net
- British Insects: the Families of Diptera by L. Watson, M.J. Dallwitz
- Calliphoridae death online
- Entomology & Death: A Procedural Guide by Elmer Paul Catts, Neal H. Haskell
- Forensic Entomology: The Utility of Arthropods in Legal Investigations by Jason H. Byrd, James L. Castner
- The blowflies of North America by David G. Hall
- Kaufman field guide to insects of North America by Eric R. Eaton, Kenn Kaufman