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Silphidae is a family of
beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s that are known commonly as large carrion beetles, carrion beetles or burying beetles. There are two subfamilies:
Silphinae Silphinae is a subfamily of burying beetles or carrion beetles. There are 113 extant species of this subfamily, in two tribe and in 14 genera. It contains the following tribes and genera: Tribes and genera * Necrodini Portevin, 1926 ** '' D ...
and Nicrophorinae. Nicrophorines are sometimes known as
sexton beetle Burying beetles or sexton beetles, genus ''Nicrophorus'', are the best-known members of the family Silphidae (carrion beetles). Most of these beetles are black with red markings on the elytra (forewings). Burying beetles are true to their name� ...
s. The number of species is relatively small at around two hundred. They are more diverse in the temperate region although a few tropical endemics are known. Both subfamilies feed on decaying
organic matter Organic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have c ...
such as dead animals. The subfamilies differ in which uses
parental care Parental care is a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring. Patterns of parental care are widespread and highly diverse across the animal ki ...
and which types of carcasses they prefer. Silphidae are considered to be of importance to
forensic entomologist 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 ...
s because when they are found on a decaying body they are used to help estimate 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 ...
.


Taxonomy, evolution, and etymology

The family Silphidae belongs to the order
Coleoptera Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describe ...
. They are commonly referred to as carrion beetles or burying beetles and are usually associated with
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
,
fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...
, and dung. In the past, members of the family
Agyrtidae Agyrtidae, or primitive carrion beetles, are a small family of beetles belonging to Staphylinoidea. They are found in mostly temperate areas of the Northern Hemisphere and in New Zealand. Characteristics Agyrtidae are small or middle-sized bee ...
were included. This family has two subfamilies, Silphinae and Nicrophorinae. The antenna is made up of 11 segments and is capitate (ending in an abruptly capped club) in the Nicrophorinae and has a more gradual club shape in the Silphinae. The subfamilies also differ in behavior. Members of the subfamily Silphinae show little to no care for their young and breed on large
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
. Nicrophorinae breed on small animal
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
and will bury themselves and their food to rear their offspring in a bi-parental manner. There are approximately 183 species in this family, which are found worldwide although they are commoner in temperate regions. '' Nicrophorus americanus'', known as the American burying beetle, is an
endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
. The oldest fossils of silphids are known from the Middle Jurassic (~ 163 million years ago)
Daohugou Bed The Haifanggou Formation (), also known as the Jiulongshan Formation (), is a fossil-bearing rock deposit located near Daohugou () village of Ningcheng County, in Inner Mongolia, northeastern China. The formation consists of coarse conglomerate ...
in Northern China. Many Silphidae are flightless although they have wings. This loss is thought to be a result due to the changes in habitat over time. Researchers have found that most flight-capable species in this group feed on
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with ...
carcasses, whereas flightless species will feed on soil
invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chorda ...
s. They also found that egg production increased with flight loss because of a more limited food supply. The word "silphid" or "sylph", first seen in the sixteenth century in
Paracelsus Paracelsus (; ; 1493 – 24 September 1541), born Theophrastus von Hohenheim (full name Philippus Aureolus Theophrastus Bombastus von Hohenheim), was a Swiss physician, alchemist, lay theologian, and philosopher of the German Renaissance. He ...
' works, refers to any race of spirits inhabiting the air and is described as mortal, but lacking soul. The word is also related to the Latin word ''silva'' meaning "forests" or "of the woods".


Diversity and distribution

Silphidae beetles are
ubiquitous Omnipresence or ubiquity is the property of being present anywhere and everywhere. The term omnipresence is most often used in a religious context as an attribute of a deity or supreme being, while the term ubiquity is generally used to descr ...
and are most abundant in the temperate zone. The diversity is also greater in the temperate zone and they are quite rare in the tropics although there are species endemic to the region. It is thought that ants, flies and other carrion feeders outcompete them in these regions. They vary in size from 7 to 45 mm. There are about 46 different species of Silphidae in North America which include ''Heterosilpha ramosa'', ''Necrodes surinamensis'', ''
Necrophila americana The American carrion beetle (''Necrophila americana'',Species Necrophila americana - American Carrion Beetle: http://bugguide.net/node/view/6744 formerly ''Silpha americana'') is a North American beetle of the family Silphidae. It lays its eggs ...
'', '' Nicrophorus americanus'', ''
Nicrophorus carolinus ''Nicrophorus carolina'' is a burying beetle Burying beetles or sexton beetles, genus ''Nicrophorus'', are the best-known members of the family Silphidae ( carrion beetles). Most of these beetles are black with red markings on the elytra (fo ...
'', ''
Nicrophorus investigator ''Nicrophorus investigator'' is a burying beetle Burying beetles or sexton beetles, genus ''Nicrophorus'', are the best-known members of the family Silphidae ( carrion beetles). Most of these beetles are black with red markings on the elytra ...
'', ''
Nicrophorus marginatus ''Nicrophorus marginatus'' is a burying beetle described by Johan Christian Fabricius Johan Christian Fabricius (7 January 1745 – 3 March 1808) was a Danish zoologist, specialising in "Insecta", which at that time included all arthropods: ...
'', ''
Nicrophorus orbicollis ''Nicrophorus orbicollis'' is a nearctic burying beetle first described by Thomas Say in 1825. It is a member of the genus '' Nicrophorus'' or sexton beetles, comprising the most common beetles in the family Silphidae. This species is a decompose ...
'', ''
Nicrophorus tomentosus ''Nicrophorus tomentosus'' (gold-necked carrion beetle or tomentose burying beetle) is a species of burying beetle that was described by Friedrich Weber in 1801. The beetle belongs to the family Silphidae which are carrion beetles. The beetles ha ...
'', ''Oiceoptoma inaequale'', ''
Oiceoptoma noveboracense ''Oiceoptoma noveboracense'' is a member of the family Silphidae, or carrion beetles, which feed on decaying organic matter such as dead animals. Its common name is the margined carrion beetle, from the orange-red margins on the pronotum, which a ...
'', ''Oiceoptoma rugulosum'', ''Thanatophilus lapponicus''. A species found in Great Britain is ''Oiceoptoma thoracicum''.


Development

Silphidae undergo
holometabolous Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult). Holometabolism is a synapomorphic trait of all insects in the superorder Endopterygota. ...
development. The development in the subfamily Silphinae proceeds at a slower rate than in Nicrophorinae. The Silphinae life cycle takes approximately twenty six to fifty eight days to go from an egg to adult. The breakdown of this process is essential to
forensic entomologist 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 ...
s. The cycle takes two to seven days after the egg is laid to hatch. 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. ...
e will develop through three
instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...
s on the
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
lasting for ten to thirty days. After that time period is up the third instar larvae will venture away from the
detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts comm ...
to
pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in thei ...
te. Pupation takes fourteen to twenty one days and is the major part of
metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...
where a grandiose change occurs. During this stage the wings become fully developed and sexual maturity is reached, sometimes called the
imago In biology, the imago (Latin for "image") is the last stage an insect attains during its metamorphosis, its process of growth and development; it is also called the imaginal stage, the stage in which the insect attains maturity. It follows the ...
or adult stage where the cycle is then repeated. The Nicrophorinae cycle is generally quicker.
Oviposition The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...
is done near the
carcass Carcass or Carcase (both pronounced ) may refer to: *Dressed carcass, the body of a livestock animal ready for butchery, after removal of skin, visceral organs, head, feet etc. *Carrion, the decaying dead body of an animal or human being *The str ...
and takes twelve to forty eight hours for the eggs to hatch into
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. ...
e. The amount of food and
parental care Parental care is a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring. Patterns of parental care are widespread and highly diverse across the animal ki ...
exhibited help determine the length of the larval stage. Pupation in this subfamily lasts six to eight days and is completed in the soil. The adult Nicrophorinae will emerge from the soil and venture to find food and a mate.


Reproduction

Nicrophorinae are well known for the habit of locating a
carcass Carcass or Carcase (both pronounced ) may refer to: *Dressed carcass, the body of a livestock animal ready for butchery, after removal of skin, visceral organs, head, feet etc. *Carrion, the decaying dead body of an animal or human being *The str ...
and burying it by unearthing the soil underneath it. The burying behavior has seemingly evolved to prevent competition from other insects such as fly
maggot A maggot is the larva 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 mosquitoes and crane flies. En ...
s. It has been observed that the cooperation of the two parent beetles leads to breeding success. More likely than not a breeding pair will work together, but in cases where there is large
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
males try to boost their reproduction by emitting
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s. In this way, he will father more offspring, but the reproductive success of the primary female steadily declines. Sometimes, where there is a large carcass the likelihood of intense competition from flies leads to communal breeding. There appears to be a truce between females who would normally compete for the males, and in these cases cooperative behavior extends to females caring for each other's offspring. At the height of breeding season pairs of beetles may compete for the
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
. The losing pair will be ejected from the
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
and if any eggs have been laid they are killed so the new female can lay her own.McGavin, George C. ''Essential Entomology: An Order-by-Order Introduction''. Oxford: Oxford University Press, 2001. pp. 62–66.


Behavior and ecology


Food

Silphid adults feed in a saprophagous manner: they colonize the
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
during all four stages of
decomposition Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and ...
, which are fresh, bloated, decay, and dry. The main areas of decomposition for adults are during both the bloated and decaying stages. Silphid larvae mainly inhabit during the decaying and dry stages of the
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
. The primary food source for the subfamily Silphinae is the
maggot A maggot is the larva 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 mosquitoes and crane flies. En ...
mass present on the
detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts comm ...
. Nicrophorinae will colonize the body earlier in decomposition in order to avoid competition with maggots. If there is a sufficiently large maggot mass they will not colonize the
carcass Carcass or Carcase (both pronounced ) may refer to: *Dressed carcass, the body of a livestock animal ready for butchery, after removal of skin, visceral organs, head, feet etc. *Carrion, the decaying dead body of an animal or human being *The str ...
. The parental care exhibited by this subfamily is that the adult beetles regurgitate food into the mouths of the young larvae until they are mature. Silphinae colonize later in the decaying process and the adults eat the maggot mass, sometimes leaving little maggot evidence left to estimate 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 ...
. In the case of the sexton or burying beetles, Nicrophorinae, the adults will bury small animal carcasses and lay their eggs on it. In some species, a slight depression is made on the
detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts comm ...
for maturing larvae that the adult beetles feed and protect. In both subfamilies the larvae are observed to eat the decaying organic material while the adults mainly consume the maggots. Flies are the major
competitor Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indivi ...
of silphids for
detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts comm ...
. If a carcass is infested with maggots, many of the Nicrophorinae will abandon the carcass while members of Silphinae will feed on the maggots.


Defense

Beetles have many different weapons available to protect them against
predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill t ...
attacks. The members of Silphidae have many different modifications that allow them to thrive in different
ecological niche In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (for ...
s including colour warnings (from
aposematism Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste ...
to
Batesian mimicry Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both. It is named after the English naturalist Henry Walter Bates, after his work on ...
), chemical defenses and
parental care Parental care is a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring. Patterns of parental care are widespread and highly diverse across the animal ki ...
. Silphines are usually dark in color consisting of gold, black and brown. This dark coloring allows them to blend into their environment. Many nicrophorines have bright orange coloring on their elytra, which may serve as a warning to other predators.Ratcliffe, B. The Carrion Beetles (Coleoptera:Silphidae) of Nebraska. ''Bulletin of the Nebraska State Museum''. Volume 13. Some species secrete a chemical from a rectal gland that consists of aliphatic acids and terpene alcohols. The secretion has a strong, foul odor and may be
topical A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes ...
ly irritating to
cockroach Cockroaches (or roaches) are a paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known ...
es and
flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced m ...
. The species ''Necrodes surinamensis'' ejects this secretion as a spray and can rotate the end of its abdomen to spray in all directions.


Locomotion and navigation

Walking is the primary form of locomotion for Silphidae beetles. They are able to travel great distances to find carcasses to breed and feed on. Beetles also have two sets of wings, the elytra and the hind wings. The hind wings are membranous and are modified for flying or swimming. There are some Silphidae who are able to fly, but others have lost this ability throughout
evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
. When an animal dies,
hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The under ...
and some
cyclic compound A cyclic compound (or ring compound) is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where ...
s are released. Silphidae use their sense of smell to locate carcasses from a long distance by chemoreceptors on their antennae, which are adapted to detect these chemicals. At a short distance, the end organs of the palpi detect the odors. Silphid beetles are usually more active at night,
nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...
, which may help reduce competition.


Competition

Competition Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, ind ...
from other organisms for the
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
puts the Silphids at both an advantage and a disadvantage. The advantage is that fly competitors lay eggs that result in
maggot A maggot is the larva 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 mosquitoes and crane flies. En ...
s and supply food for Silphids. The disadvantage for the Nicrophorinae is that if the carcass is already “blown”, referring to
Shakespeare William Shakespeare ( 26 April 1564 – 23 April 1616) was an English playwright, poet and actor. He is widely regarded as the greatest writer in the English language and the world's pre-eminent dramatist. He is often called England's nation ...
an time as being infected with fly maggots, they will not colonize. Nicrophorinae have adapted to these situations and will bury the
carcass Carcass or Carcase (both pronounced ) may refer to: *Dressed carcass, the body of a livestock animal ready for butchery, after removal of skin, visceral organs, head, feet etc. *Carrion, the decaying dead body of an animal or human being *The str ...
to remove it from other competitors. With this technique, a steady food source is available for the larvae and procreation chances increase. Silphidae compete for
brood Brood may refer to: Nature * Brood, a collective term for offspring * Brooding, the incubation of bird eggs by their parents * Bee brood, the young of a beehive * Individual broods of North American Periodical Cicadas: ** Brood X, the largest b ...
ing areas. If an invader male overpowers the original male, it will mate with the original female and create a new
brood Brood may refer to: Nature * Brood, a collective term for offspring * Brooding, the incubation of bird eggs by their parents * Bee brood, the young of a beehive * Individual broods of North American Periodical Cicadas: ** Brood X, the largest b ...
. If an invader female overpowers the original female, it will also create a new
brood Brood may refer to: Nature * Brood, a collective term for offspring * Brooding, the incubation of bird eggs by their parents * Bee brood, the young of a beehive * Individual broods of North American Periodical Cicadas: ** Brood X, the largest b ...
with the primary male.


Relationships


With humans

Silphids are usually not considered a
nuisance Nuisance (from archaic ''nocence'', through Fr. ''noisance'', ''nuisance'', from Lat. ''nocere'', "to hurt") is a common law tort. It means that which causes offence, annoyance, trouble or injury. A nuisance can be either public (also "common") ...
to humans. They help the environment by laying their eggs on carcasses and the larvae break down the
detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts comm ...
, which prevents accumulation of deceased organisms. Carcasses are kept out of sight and foul odors are prevented when Nicrophorinae bury it under the ground. This will also reduce the surface area for flies to lay their eggs and decrease fly population. Some Silphidae occupy human-inhabited areas and become pests to farmers by using crops as a second source of nutrients. ''Aclypea opaca'' in Europe feed on beets. ''Necrophila americana'' feed on pumpkin, spinach, and sugar beet.


With other organisms

Members from the family Silphidae are known to have mutualistic relationships with other organisms. Nicrophorinae have a mutual relationship with phoretic
mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...
s. Mites from the genus ''
Poecilochirus ''Poecilochirus'' is a Holarctic genus of mites in the family Parasitidae. They are relatively large (ca. 0.5-1mm) and often found on rotting corpses, where they are transported by beetles. Deuteronymphs are characterized by two orange dorsal s ...
'' produce deutonymphs that crawl on Nicrophorinae and are transported to
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
. Once they arrive at the
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
, deutonymphs leave the adult Nicrophorinae and proceed to feed on nearby fly eggs and immature
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. ...
e. Mites help Nicrophorinae reduce the number of competitors on
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
. With less competition, both species are able to reproduce successfully underground. Silphidae are known for being hosts to juvenile
nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant- parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...
s. ''Nicrophorus vespilloides'' are closely associated with the
nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant- parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...
parasite. The parasites can be easily transmitted to other hosts during
copulation Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...
.


Forensic research

Silphidae are one of several families of
forensic Forensic science, also known as criminalistics, is the application of science to criminal and civil laws, mainly—on the criminal side—during criminal investigation, as governed by the legal standards of admissible evidence and criminal p ...
importance in the order
Coleoptera Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describe ...
. They are a very important tool in determining 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 ...
by collecting Silphid progeny from the
carcass Carcass or Carcase (both pronounced ) may refer to: *Dressed carcass, the body of a livestock animal ready for butchery, after removal of skin, visceral organs, head, feet etc. *Carrion, the decaying dead body of an animal or human being *The str ...
, and determining the developmental rate. Based on the number of instars and the larval development stage, a time of death can be estimated. This is very useful in medicocriminal entomology, the emphasis on utilizing
arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...
s as
evidence Evidence for a proposition is what supports this proposition. It is usually understood as an indication that the supported proposition is true. What role evidence plays and how it is conceived varies from field to field. In epistemology, evidenc ...
to aid in solving crimes. Many of the methods in determining stages of development are subjective. However, recent studies have found a more precise way of determining the stage of development of Silphid larvae by measuring the maximum cranial width and other heavily sclerotized areas of the larvae instead of measuring just the length, which is subject to change with each larva, particularly in ''O. inaequale'' and ''N. surinamensis'', which are more robust and have greater variations of length. The most accurate instar identification is possible by using distinct morphological features that are instar specific and cannot be affected by the size of the specimen. Although this is possible only for few species with described larvae of all instars, such as '' Thanatophilus rugosus''. Silphidae are being studied to find more exact estimations of
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 ...
s and possible manners of death. Also, in the future, entomologists will explore the social behavior of the beetles to a greater degree. Members of family Silphidae are typically the first of the
coleoptera Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describe ...
ns to come in contact with
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
. Silphidae
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. ...
e are opportunistic
predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill t ...
s that will feed on
diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...
n eggs, larvae, and on the carcass itself. This presents a problem in the determination of post-mortem interval because Silphidae are known to eradicate other species from carrion. By eliminating the first colonizing species Silphidae can give an incorrect post-mortem interval. Unlike most of the insects used as forensic markers, it is possible to assess if Silphidae adults have colonized a corpse and left it later. For this purpose, some
Parasitidae Parasitidae is a family of predatory mites in the order Mesostigmata that has worldwide distribution. They are the only family in the superfamily Parasitoidea. Relatively large for mites, their color is often yellowish to dark brown. The family a ...
mites (for example, ''Poecilochirus'' species) are used due to their phoront-host specificity. If a corpse is invaded by ''Poecilochirus'' specimens and no Silphidae were sampled by forensic entomologists, it is reasonable to suspect that some Silphidae carrying ''Poecilochirus'' phoretic instars arrived previously to the corpse and abandoned it some time later, leaving ''Poecilochirus'' mites in the process.


References


External links


Horn, GH (1880) Synopsis of the Silphidae of the United States with reference to the genera of other countries.
{{Authority control Beetle families Staphylinoidea Taxa named by Pierre André Latreille Scavengers