Oiceoptoma noveboracense
Encyclopedia
Oiceoptoma noveboracense is a member of the family Silphidae, or 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...

 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. The larva is typically light brown to red and also has vertical ridges on its thorax like the adult. This diurnal beetle can be found mainly in the spring into the fall, and it has a strong preference towards a deciduous forest habitat. The primary forensic importance of this beetle is its ability to use the succession of insect fauna to provide confirmation of postmortem intervals.

Taxonomy

Oiceoptoma noveboracense's Latin specific name means "pertaining to New York" (Latin Novum Eboracum
Eboracum
Eboracum was a fort and city in Roman Britain. The settlement evolved into York, located in North Yorkshire, England.-Etymology:The first known recorded mention of Eboracum by name is dated circa 95-104 AD and is an address containing the Latin form of the settlement's name, "Eburaci", on a wooden...

+ -ensis), referring to the original source of the type specimen. Although less common, some literature will refer to the species as Oiceoptoma noveboracensis. The genus Oiceoptoma was described by the English naturalist, William Elford Leach
William Elford Leach
William Elford Leach FRS was an English zoologist and marine biologist.Leach was born at Hoe Gate, Plymouth, the son of a solicitor. At the age of twelve he went to school in Exeter, studying anatomy and chemistry. By this time he was already collecting marine samples from Plymouth Sound and along...

, in 1815.

Description

Oiceoptoma noveboracense larvae range from light brown to dark reddish in color. The larvae are typically flat and trilobite
Trilobite
Trilobites are a well-known fossil group of extinct marine arthropods that form the class Trilobita. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period , and they flourished throughout the lower Paleozoic era before...

-like in appearance. They are capable of moving locations during their development.

The adults average from 13 to 15 mm (0.511811023622047 to 0.590551181102362 in) long. The middle of the pronotum (dorsal side, first segment of the thorax) on this beetle is dark-brown to black in color. The outer margins are outlined in a bright orange-red (salmon colored). The elytra are hardened forewings used to protect the fragile hind wings underneath. The elytra are attached to the suture that runs down the middle of the beetle's back and range from reddish-brown to black. They have a distinctive tooth at the shoulder and the vertical ridges are very apparent. This elytra apex is rounded on males, whereas it is more tapered on the female body. O. noveboracense have temple regions behind their eyes that have a long line of erect setae that are of a yellowish tint and the inner tomora
Tomora
Tomora is a commune in the Cercle of Bafoulabé in the Kayes Region of south-western Mali. The principal town lies at Oussoubidiagna, a small town with around 4,000 inhabitants. As of 1998 the commune had a population of 25,844...

 is a ridge-free region. The metatibiae are enlarged on the males ranging from moderate to large in size.

Life cycle

Oiceoptoma noveboracense is a diurnal species, meaning that it is primarily active during the daytime. This beetle produces one generation per year. Reproduction begins in the spring and depending on temperature it takes approximately forty-five days from the instance of mating to the emergence of the adult from the pupa. The eggs are laid in the carrion so that once they become 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...

 they will begin to feed on their substrate. As is common with most Silphidae, the adults will typically feed on carrion as well as the larva of flies that are also feeding on the carrion.

During the springtime when mating is observable, adults are commonly found paired with the males mounted on the females. This position will be maintained for periods of time even though copulation may not be occurring at that instant. Typically, males will firmly take hold of the female’s antennae with their mandibles in order to position themselves for sexual activity. Once copulation is achieved the male will release the female’s antenna and begin to slide backward onto the female’s elytra. He will then begin to use his antennae to stroke the pronotum of the female. Again the male searches for and grabs the female’s antennae and this series of events is repeated. This activity will occur frequently until the female oviposits. Males have not been seen to be sexually active when the eggs and/or instar larvae are present at the carcass. This behavior suggests that the males might use this time to insure paternity of the offspring of the particular female with which he mated.

Distribution and habitat

Oiceoptoma noveboracense is most commonly found in deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 forests or in grasslands and fields. It will less frequently inhabit marshes. When the species is found in a marsh, the area is typically prone to seasonal inundation. This causes the marsh to superficially resemble a dried field habitat.

O. noveboracense is found from the Atlantic coast of the Northeastern United States, extending along the northern edge of the prairies west to the Rocky Mountains. It may be present as far south as Texas.

Forensic

Due to its widespread distribution, Oiceoptoma noveboracense is frequently found on carrion and associated crime scene investigations. They are currently used to substantiate and support insect colonization timelines and help estimate Post-mortem interval (PMI). Arriving variably after initial insect colonizers (flies), the adults will prey on fly maggots and rarely feed on the carrion. They can also be found in the later stages of decomposition depending on variables like temperature, climate, and location of the carrion. Ultimately, if found, these beetles corroborate the PMI data of the more useful insect colonizers with succession-pattern based information.

Medical

The medical importance of Oiceoptoma noveboracense has yet to be substantially determined. However, a study has found its hindgut, midgut, and associated hemolymph
Hemolymph
Hemolymph, or haemolymph, is a fluid in the circulatory system of some arthropods and is analogous to the fluids and cells making up both blood and interstitial fluid in vertebrates such as birds and mammals...

 can potentially harbor known opportunistic bacterial pathogens. Of these opportunistic pathogens, the majority of the identified bacteria were either coliform or staphylococci.

Current and future research

Previous research investigated the seasonal activity and habitat preferences of this necrophagous beetle. Overall it has been observed that this Silphid species prefers the forest environment and warmer months.

The ability of O. noveboracense to transmit microorganisms has also been researched. In one study it was confirmed that medically true bacteria were found in the midgut, hindgut, and associated hemolymph
Hemolymph
Hemolymph, or haemolymph, is a fluid in the circulatory system of some arthropods and is analogous to the fluids and cells making up both blood and interstitial fluid in vertebrates such as birds and mammals...

. Even though these bacteria were isolated, it is only hypothesized that they may serve as a reservoir host. Further research could determine whether O. noveboracense is able to actually transmit the bacteria present. More succession studies may be able to narrow the time frame at which this beetle is attracted to carrion.

External links

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