Carrion beetle
Encyclopedia
Silphidae is a family of beetle
s that are known commonly as carrion or burying beetles. There are two subfamilies
: Silphinae and Nicrophorinae. Both families feed on decaying organic matter
such as dead animals. The families differ in which uses parental care
and which types of carcasses they prefer. Silphidae are considered to be of importance to forensic entomologist
s because when they are found on a decaying body they are used to help estimate a post-mortem interval or PMI.
. They are commonly referred to as carrion beetles or burying beetles and are usually associated with carrion
, fungi
, and dung
. This family has two main subfamilies, Silphinae and Nicrophorinae. The subfamilies are divided primarily on behavioral foundations. Members of the subfamily Silphinae show little to no care for their young and breed on large carrion
. Nicrophorinae breed on small carrion
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. The Nicrophorus americanus
, known as the American Burying Beetle, is an endangered species
. The word "silphid" or "sylph", first seen in the sixteenth century in Paracelsus
' 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 sylva meaning "slender, graceful girl" and the Greek word nymph meaning "light, airy movements".
period. Beetles have diversified into many different sizes and forms. A possible reason for the great success of beetles is that there are such a high number of lineages that may have emerged due to a variation among ecological niche
s. Many members of the family Silphidae are flightless, but have wings. The evolutionary change 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
carcasses, whereas flightless species will feed on soil invertebrate
s. They also found that egg production increased with flight loss because of a more limited food supply. The reason behind this is because with less food more offspring would die before reaching sexual maturity.
A fossil of N. humator
dating around 10,500 years was described in 1962 by Pearson.
and abundant. They are found worldwide. There are 46 different species of Silphidae located in North America, many of which are found in the United States.
United Kingdom
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
s. The cycle takes two to seven days after the egg is laid to hatch. The larva
e will develop through three instar
s on the carrion
lasting for ten to thirty days. After that time period is up the third instar larvae will venture away from the detritus
to pupa
te. Pupation takes fourteen to twenty one days and is the major part of metamorphosis
where a grandiose change occurs. During this stage the wings become fully developed and sexual maturity is reached, sometimes called the imago
or adult stage where the cycle is then repeated. The Nicrophorinae cycle is generally quicker. Oviposition
is done near the carcass
and takes twelve to forty eight hours for the eggs to hatch into larva
e. The amount of food and parental care
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.
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
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
males try to boost their reproduction by emitting pheromone
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 others' offspring. At the height of breeding season pairs of beetles may compete for the carrion
. The losing pair will be ejected from the carrion
and if any eggs have been laid they are killed so the new female can lay her own.
during all four stages of decomposition
, which are fresh, bloated, decay, and dry. The main areas of decomposition for adults are during both the bloated and decaying stages. The Silphidae larvae mainly inhabit during the decaying and dry stages of the carrion
. The primary food source for the subfamily Silphinae is the maggot
mass present on the detritus
. The 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
. 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. 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
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
of Silphiade for detritus
. If a carcass is infested with maggots, many of the Nicrophorinae will abandon the carcass while members of Silphinae will feed on the maggots.
s including colour warnings (from aposematism
to Batesian mimicry
), chemical defenses and parental care
. Silphid beetles are usually dark in color consisting of gold, black and brown. This dark coloring allows them to blend in to their environment. One species of Silphidae uses a physical mean of defense. Oiceoptoma inaequalis holds its elytra over its back when it flies. The back of the elytra are bright blue and when they are exposed it makes the beetle look much larger. After landing, the beetle folds its wings and the blue color vanishes. Many Silphidae have bright orange coloring on their elytra, which may serve as a warning to other predators. Some Silphidae beetles 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
ly irritating to Blattodea
and Diptera
. The species Necrodes surinamensis ejects this secretion as a spray and can rotate the end of its abdomen to spray in all directions.
a are three pairs of thoracic
legs. Like many other insect orders, beetles have claws at the end of each leg, called tarsi
that help in walking and climbing. 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
. When an animal dies, hydrogen sulfide
and some cyclic compound
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, which may help reduce competition.
from other organisms for the carrion
puts the Silphids at both an advantage and a disadvantage. The advantage is that fly competitors lay eggs that result in maggot
s and supply food for Silphids. The disadvantage for the Nicrophorinae is that if the carcass is already “blown”, referring to Shakespearean time as being infected with fly maggots, they will not colonize. Nicrophorinae have adapted to these situations and will bury the carcass
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
ing areas. If an invader male overpowers the original male, it will mate with the original female and create a new brood
. If an invader female overpowers the original female, it will also create a new brood
with the primary male.
and the larvae break down the detritus
, 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.
s. Mites from the genus Poecilochirus produce deutonymphs that crawl on Nicrophorinae and are transported to carrion
. Once they arrive at the carrion
, deutonymphs leave the adult Nicrophorinae and proceed to feed on nearby fly eggs and immature larva
e. Mites help Nicrophorinae reduce the amount of competitors on carrion
. With less competition, both species are able to reproduce successfully underground.
Silphidae are known for being hosts to juvenile nematode
s. Nicrophorus vespilloides are closely associated with the nematode
parasite. The parasites can be easily transmitted to other hosts during copulation
.
, and determining the developmental rate. Based on the number of instars present and what stage of development they are in, a time of death can be estimated. This is very useful in medicocriminal entomology
, the emphasis on utilizing arthropod
s as evidence
to aid in solving crimes. Many of the methods in determining stages of development are subjective. Fortunately, recent studies have found a new way of determining what stage of development Silphid larvae are in 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 respectively. In terms of future research, Silphidae are being studied to find more exact PMI estimations 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
ns to come in contact with carrion
. Silphidae larva
e are opportunistic predators that will feed on diptera
n eggs, larvae, and on the carcass itself. This presents a problem in the determination of post-mortem interval (PMI) because Silphidae are known to eradicate other species from carrion. By eliminating the first colonizing species Silphidae can give an incorrect PMI.
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s that are known commonly as carrion or burying beetles. There are two subfamilies
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...
: Silphinae and Nicrophorinae. Both families feed on decaying organic matter
Organic matter
Organic matter is matter that has come from a once-living organism; is capable of decay, or the product of decay; or is composed of organic compounds...
such as dead animals. The families differ in which uses parental care
Parenting
Parenting is the process of promoting and supporting the physical, emotional, social, and intellectual development of a child from infancy to adulthood...
and which types of carcasses they prefer. Silphidae are considered to be of importance to forensic entomologist
Forensic entomologist
Forensic entomologists are those involved in the branch of entomology that involves insects and violent crime or the law, known as forensic entomology. This includes three main branches: medicocriminal entomology, urban entomology, and stored product entomology...
s because when they are found on a decaying body they are used to help estimate a post-mortem interval or PMI.
Taxonomy and etymology
The family Silphidae belongs to the order ColeopteraBeetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
. They are commonly referred to as carrion beetles or burying beetles and are usually associated with 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...
, fungi
Fungus
A fungus is a member of a large 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, Fungi, which is separate from plants, animals, and bacteria...
, and dung
Feces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
. This family has two main subfamilies, Silphinae and Nicrophorinae. The subfamilies are divided primarily on behavioral foundations. Members of the subfamily Silphinae show little to no care for their young and breed on large 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...
. Nicrophorinae breed on small 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...
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. The Nicrophorus americanus
Nicrophorus americanus
Nicrophorus americanus, also known as the American burying beetle or giant carrion beetle, is a critically endangered species of beetle endemic to North America. It belongs to the order Coleoptera and the family Silphidae. The carrion beetle in North America is carnivorous, feeds on carrion and...
, known as the American Burying Beetle, is an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
. The word "silphid" or "sylph", first seen in the sixteenth century in Paracelsus
Paracelsus
Paracelsus was a German-Swiss Renaissance physician, botanist, alchemist, astrologer, and general occultist....
' 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 sylva meaning "slender, graceful girl" and the Greek word nymph meaning "light, airy movements".
Evolution
The oldest beetle fossils are over 265 million years old dating back to the PermianPermian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
period. Beetles have diversified into many different sizes and forms. A possible reason for the great success of beetles is that there are such a high number of lineages that may have emerged due to a variation among ecological niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
s. Many members of the family Silphidae are flightless, but have wings. The evolutionary change 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
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
carcasses, whereas flightless species will feed on soil invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s. They also found that egg production increased with flight loss because of a more limited food supply. The reason behind this is because with less food more offspring would die before reaching sexual maturity.
A fossil of N. humator
Nicrophorus humator
Nicrophorus humator is a burying beetle described by Gleditsch in 1767. A fossil dating around 10,500 years was described in 1962 by Pearson....
dating around 10,500 years was described in 1962 by Pearson.
Diversity and distribution
Silphidae beetles are ubiquitousOmnipresence
Omnipresence or ubiquity is the property of being present everywhere. According to eastern theism, God is present everywhere. Divine omnipresence is thus one of the divine attributes, although in western theism it has attracted less philosophical attention than such attributes as omnipotence,...
and abundant. They are found worldwide. There are 46 different species of Silphidae located in North America, many of which are found in the United States.
- Heterosilpha ramosa is located in the western portion of the United States from California to New Mexico and up to Nebraska and Montana. It can also be found in southwestern Canada. It is noted for having a dark brown or black pronotumProthoraxThe prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
and elytra. It is most active throughout the warmer months of spring and summer and feeds on fresh carrion and that of advanced decomposition.
- Necrodes surinamensis is found throughout central and southern Canada and all throughout the United States, except in the Southwestern portion. It has a glossy black pronotum with dull elytra having pronounced longitudinal ridges and red markings at the tip. N. surinamensis is nocturnal and is active in the spring months. They are found on larger carcasses.
- Necrophila americana is found east of Texas up through Minnesota and in southeastern Canada. They are noted for a yellow pronotumProthoraxThe prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
with a black center and dull black elytra with crossed ridges making a oval shaped body. They are active during the daylight hours from spring through fall and feed on carrionCarrionCarrion 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...
and larvaLarvaA 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 of other insects present on the carcassCarrionCarrion 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...
.
- Nicrophorus americanusNicrophorus americanusNicrophorus americanus, also known as the American burying beetle or giant carrion beetle, is a critically endangered species of beetle endemic to North America. It belongs to the order Coleoptera and the family Silphidae. The carrion beetle in North America is carnivorous, feeds on carrion and...
is located from Florida to east Texas up through Michigan, and sometimes in southeastern Canada. They have a long pronotum with orange or red markings down to the elytra. It is 30–35 mm long, making it the largest of the genus Nicrophorus. This species is rarely collected due to its nocturnal behavior and is considered an endangered speciesEndangered speciesAn endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.
- Nicrophorus carolinusNicrophorus carolinusNicrophorus carolinus is a burying beetle described by Linnaeus in 1771.-References:http://collections2.eeb.uconn.edu/nicroweb/PDFs/Sikes_et_al_2002.pdf...
is noted for having a very narrow pronotumProthoraxThe prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
that is black and shiny on the anterior portion, yet dull on the posterior portion. It is also noted for distinct orange markings. It can be found along the Atlantic coast of Virginia through Georgia and the Gulf Coast of Texas and Alabama. It can also be found in north Texas, Colorado, and Wyoming, even some parts of Arizona.
- Nicrophorus investigatorNicrophorus investigatorNicrophorus is a burying beetle described by Zetterstedt in 1824.-References:http://collections2.eeb.uconn.edu/nicroweb/PDFs/Sikes_et_al_2002.pdf...
varies widely in color, but is noted for having a wide pronotum. It can be found in the northwestern United States, and along the U.S.-Canadian border, but has been found in New Mexico and Arizona. The pupal stages typically overwinter and the adult stages emerge in the summer.
- Nicrophorus marginatusNicrophorus marginatusFor the species misidentified by Gistel in 1857 and declared a new species under the name Nicrophorus marginatus, but later corrected, see Nicrophorus tomentosusNicrophorus marginatus is a burying beetle described by Fabricius in 1801....
has a glossy black pronotumProthoraxThe prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
with orange hairs located behind the head. The elytra are very short, glossy black with orange markings. They can be found in southern Canada and all throughout the United States except in Florida and Georgia. They are typically nocturnal and feed on maggotMaggotIn 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...
s, and are known to bury animal carcasses to ovipositOvipositionOviposition 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....
.
- Nicrophorus orbicollisNicrophorus orbicollisNicrophorus 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 decomposer feeding on carcasses of small dead animals. N...
is known for having elongated black pronotum and short black elytra with two rows of orange spots. They are located in southeastern and south-central Canada, east Texas and north to the Dakotas. They are nocturnal and are active in the warmer months of the year upon overwintering.
- Nicrophorus tomentosusNicrophorus tomentosusGold-necked carrion beetle, Nicrophorus tomentosus, is a species of burying beetle that was described by Friedrich Weber in 1801. The beetle belongs to the Silphidae family whom are carrion beetles. The beetles have sensitive antennae that contain olfactory organs. Thus, the beetle can locate dead...
is the easiest species to distinguish of Silphidae due to its small size of about 15 mm and dense gold hairs on its pronotumProthoraxThe prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
. It can be found in southeastern and central Canada and throughout the eastern and central United States except south Texas and Florida. Unlike other beetleBeetleColeoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s of the same genus, instead of burying the carcass, they remove the soil from underneath it, allowing it to sink underground. They are active in the summer months.
- Oiceoptoma inaequale is black from the pronotum to the elytra and is located in the eastern United States and southeastern Canada. They are abundant from the spring through the fall, and are active throughout the day.
- Oiceoptoma noveboracenseOiceoptoma noveboracenseOiceoptoma 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 are helpful when identifying this species...
is noted for having a black or dark brown pronotumProthoraxThe prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites are the pronotum , the prosternum , and the propleuron on each side. The prothorax never bears wings in extant insects, though some fossil groups possessed...
with orange margins, and a red-brown elytra with distinct longitudinal ridges. They can be found in southern Canada and the central United States. They are active during the day and abundant during the spring months, like most species of their genus, they also overwinter.
- Oiceoptoma rugulosum is dull, black and has an oval shaped body with four prominent longitudinal ridges on the elytra. They can be found in Florida, Texas and Louisiana. They prefer human remains where they prey on maggotMaggotIn 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...
s.
- Thanatophilus lapponicus has a black pronotum with some bits of gold and gray, and a brown-black elytra. The body tends to have a textured appearance. It can be found in the northeastern United States and parts of southern California, New Mexico, Arizona, even Alaska and Canada. Prominent in the summer, but it can bear the cold. It thrives on fresh carrionCarrionCarrion 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...
and carcassesCarrionCarrion 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 advanced decomposition where it preys on insect larvae.
United Kingdom
- Oiceoptoma thoracicum http://www.panoramio.com/photo/35226116
Development
Silphidae undergo holometabolousHolometabolism
Holometabolism, also called complete metamorphism, is a term applied to insect groups to describe the specific kind of insect development which includes four life stages - as an embryo or egg, a larva, a pupa and an imago or adult. Holometabolism is a monophyletic trait that all insects in the...
development. The development in the subfamily Silphinae proceeds at a slower rate than in Nicrophorinae. The Silphinae life cycle
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
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 entomologist
Forensic entomologists are those involved in the branch of entomology that involves insects and violent crime or the law, known as forensic entomology. This includes three main branches: medicocriminal entomology, urban entomology, and stored product entomology...
s. The cycle takes two to seven days after the egg is laid to hatch. The larva
Larva
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 will develop through three 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...
s on the 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...
lasting for ten to thirty days. After that time period is up the third instar larvae will venture away from the detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
to 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...
te. Pupation takes fourteen to twenty one days and is the major part of metamorphosis
Metamorphosis
Metamorphosis is a biological process by which an animal physically develops after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation...
where a grandiose change occurs. During this stage the wings become fully developed and sexual maturity is reached, sometimes called the 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 stage where the cycle is then repeated. The Nicrophorinae cycle is generally quicker. 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....
is done near the carcass
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...
and takes twelve to forty eight hours for the eggs to hatch into larva
Larva
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. The amount of food and parental care
Parenting
Parenting is the process of promoting and supporting the physical, emotional, social, and intellectual development of a child from infancy to adulthood...
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 carcassCarrion
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...
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
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...
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
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...
males try to boost their reproduction by emitting pheromone
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 outside the body of the secreting individual to impact the behavior of the receiving individual...
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
Cooperative breeding
Cooperative breeding is a social system in which individuals contribute care to offspring that are not their own at the expense of their own reproduction . When reproduction is monopolized by one or few of the adult group members and most adults do not reproduce, but help rear the breeder’s...
. 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 others' offspring. At the height of breeding season pairs of beetles may compete for the 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...
. The losing pair will be ejected from the 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...
and if any eggs have been laid they are killed so the new female can lay her own.
Food
The Silphidae adults feed in a saprophagous manner, which means they feed on decaying matter. The beetles colonize the 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...
during all four stages of decomposition
Decomposition
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...
, which are fresh, bloated, decay, and dry. The main areas of decomposition for adults are during both the bloated and decaying stages. The Silphidae larvae mainly inhabit during the decaying and dry stages of the 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...
. The primary food source for the subfamily Silphinae is 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...
mass present on the detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
. The 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
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...
. 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. 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
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
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
Competition is a contest between individuals, groups, animals, etc. for territory, a niche, or a location of resources. It arises whenever two and only two strive for a goal which cannot be shared. Competition occurs naturally between living organisms which co-exist in the same environment. For...
of Silphiade for detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
. 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 attacks. The members of Silphidae have many different modifications that allow them to thrive in different ecological nicheEcological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
s including colour warnings (from aposematism
Aposematism
Aposematism , perhaps most commonly known in the context of warning colouration, describes a family of antipredator adaptations where a warning signal is associated with the unprofitability of a prey item to potential predators...
to Batesian mimicry
Batesian mimicry
Batesian mimicry is a form of mimicry typified by a situation where a harmless species has evolved to imitate the warning signals of a harmful species directed at a common predator...
), chemical defenses and parental care
Parenting
Parenting is the process of promoting and supporting the physical, emotional, social, and intellectual development of a child from infancy to adulthood...
. Silphid beetles are usually dark in color consisting of gold, black and brown. This dark coloring allows them to blend in to their environment. One species of Silphidae uses a physical mean of defense. Oiceoptoma inaequalis holds its elytra over its back when it flies. The back of the elytra are bright blue and when they are exposed it makes the beetle look much larger. After landing, the beetle folds its wings and the blue color vanishes. Many Silphidae have bright orange coloring on their elytra, which may serve as a warning to other predators. Some Silphidae beetles 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
Topical
In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears.Many topical medications are epicutaneous, meaning that they are applied directly to the skin...
ly irritating to Blattodea
Cockroach
Cockroaches are insects of the order Blattaria or Blattodea, of which about 30 species out of 4,500 total are associated with human habitations...
and Diptera
Fly
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...
. 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
A few of the defining characteristics of the class InsectInsect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
a are three pairs of thoracic
Thorax (insect anatomy)
The thorax is the mid section of the insect body. It holds the head, legs, wings and abdomen. It is also called mesosoma in other arthropods....
legs. Like many other insect orders, beetles have claws at the end of each leg, called tarsi
Arthropod leg
The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments are of Latin origin, and may be confused with terms for bones: coxa , trochanter , femur, tibia, tarsus, ischium, metatarsus, carpus, dactylus ,...
that help in walking and climbing. Walking is the primary form of locomotion for Silphidae beetles. They are able to travel great distances to find carcasses
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...
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
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
. When an animal dies, hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
and some cyclic compound
Cyclic compound
In chemistry, a cyclic compound is a compound in which a series of atoms is connected to form a loop or ring.While the vast majority of cyclic compounds are organic, a few inorganic substances form cyclic compounds as well, including sulfur, silanes, phosphanes, phosphoric acid, and triboric acid. ...
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, which may help reduce competition.
Competition
CompetitionCompetition
Competition is a contest between individuals, groups, animals, etc. for territory, a niche, or a location of resources. It arises whenever two and only two strive for a goal which cannot be shared. Competition occurs naturally between living organisms which co-exist in the same environment. For...
from other organisms for the 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...
puts the Silphids at both an advantage and a disadvantage. The advantage is that fly competitors lay eggs that result in 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...
s and supply food for Silphids. The disadvantage for the Nicrophorinae is that if the carcass is already “blown”, referring to Shakespearean time as being infected with fly maggots, they will not colonize. Nicrophorinae have adapted to these situations and will bury the carcass
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...
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
Offspring
In biology, offspring is the product of reproduction, of a new organism produced by one or more parents.Collective offspring may be known as a brood or progeny in a more general way...
ing areas. If an invader male overpowers the original male, it will mate with the original female and create a new brood
Offspring
In biology, offspring is the product of reproduction, of a new organism produced by one or more parents.Collective offspring may be known as a brood or progeny in a more general way...
. If an invader female overpowers the original female, it will also create a new brood
Offspring
In biology, offspring is the product of reproduction, of a new organism produced by one or more parents.Collective offspring may be known as a brood or progeny in a more general way...
with the primary male.
With humans
Silphids are usually not considered a nuisance to humans. They help the environment by laying their eggs on carcassesCarrion
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...
and the larvae break down the detritus
Detritus
Detritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
, 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 Silphidae family are known to have a mutualistic relationships with other organisms. Nicrophorinae have a mutual relationship with phoretic miteMite
Mites, along with ticks, are small arthropods belonging to the subclass Acari and the class Arachnida. The scientific discipline devoted to the study of ticks and mites is called acarology.-Diversity and systematics:...
s. Mites from the genus Poecilochirus produce deutonymphs that crawl on Nicrophorinae and are transported to 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...
. Once they arrive at the 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...
, deutonymphs leave the adult Nicrophorinae and proceed to feed on nearby fly eggs and immature larva
Larva
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. Mites help Nicrophorinae reduce the amount of competitors 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...
. With less competition, both species are able to reproduce successfully underground.
Silphidae are known for being hosts to juvenile nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
s. Nicrophorus vespilloides are closely associated with the nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
parasite. The parasites can be easily transmitted to other hosts during copulation
Sexual intercourse
Sexual intercourse, also known as copulation or coitus, commonly refers to the act in which a male's penis enters a female's vagina for the purposes of sexual pleasure or reproduction. The entities may be of opposite sexes, or they may be hermaphroditic, as is the case with snails...
.
Forensic research
Silphidae are one of several families of forensic importance in the order Coleoptera. They are a very important tool in determining a post-mortem interval by collecting Silphid progeny from the carcassCarrion
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...
, and determining the developmental rate. Based on the number of instars present and what stage of development they are in, a time of death can be estimated. This is very useful in medicocriminal 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...
, the emphasis on utilizing 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...
s as evidence
Evidence
Evidence in its broadest sense includes everything that is used to determine or demonstrate the truth of an assertion. Giving or procuring evidence is the process of using those things that are either presumed to be true, or were themselves proven via evidence, to demonstrate an assertion's truth...
to aid in solving crimes. Many of the methods in determining stages of development are subjective. Fortunately, recent studies have found a new way of determining what stage of development Silphid larvae are in by measuring the maximum cranial width and other heavily sclerotized
Sclerosis (medicine)
In medicine, sclerosis refers to the stiffening of a structure, usually caused by a replacement of the normal organ-specific tissue with connective tissue.Types include:...
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 respectively. In terms of future research, Silphidae are being studied to find more exact PMI estimations 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
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
ns to come in contact with 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...
. Silphidae larva
Larva
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 opportunistic predators that will feed on diptera
Fly
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...
n eggs, larvae, and on the carcass itself. This presents a problem in the determination of post-mortem interval (PMI) because Silphidae are known to eradicate other species from carrion. By eliminating the first colonizing species Silphidae can give an incorrect PMI.
External links
- Beetle News Beginner's Guide : Silphidae (Part 2) - Richard Wright (ISSN 2040-6177, October 2009).