American carrion beetle

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American carrion beetle
American carrion beetle.JPG
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Silphidae
Genus: Necrophila
Species:
N. americana
Binomial name
Necrophila americana
Synonyms

The American carrion beetle (Necrophila americana, [1] formerly Silpha americana) is a North American beetle of the family Silphidae. It lays its eggs in, and its larvae consume, raw flesh (particularly that of dead animals) and fungi. The larvae and adults also consume fly larvae and the larvae of other carrion beetles that compete for the same food sources as their larvae. [2] [3] They prefer to live in marshy and woody habitats. [4] [5] Necrophila americana emerge from their larval state in the early summer. [6] The P. ashtoni cuckoo bumble bee displays close mimicry with the American carrion beetle. [7] They are important in forensic studies because of their tendency to thrive on large carcasses. [8]

Contents

Appearance

Necrophila americana are distinctive in that they have a relatively large, broadly rounded, and flattened body with a yellow pronotum. It is the only North American silphid with a mostly yellow pronotum, and it is the only species of Necrophila found in North America, as all other species are found in Asia. There is sexual dimorphism, with the males having rounded elytral apices and females having their apices more prolonged. They typically range from 12 to 22 millimeters long. The larvae can be characterized by their black color, two-segmented urogomphi, and the presence of numerous plates on the sensory area of the second antennal segment. [9]

Range

The beetle lives in North America, east of the Rocky Mountains. Its southern boundary is from eastern Texas to Florida and the northern boundary is from Minnesota to southeastern Canada, including New Brunswick and Maine. [3]

Habitat

Dense populations of N. americana have been found in eastern parts of Kansas. Over half of the 140 specimens collected (65%) were reported to be found in wooded areas, while 25% were found in marginal areas of woods. They are often found in open fields, while being rarely found in open meadows. [10] However, it has also been shown that in habitats with trees present, the beetles prefer habitats that are humid and overgrown with thick trees, as opposed to the meadows or fields. [4]

Other studies have shown that the American carrion beetle also reside in Typha marsh habitats, with lots of water accumulation and heavy rainfall. They prefer marshes over woody areas such as forests, but still prefer both of these habitats over open meadows, which they are rarely found in. [5]

Food resources

As adults, N. americana can be captured using carcass bait in a pitfall trap. Their appearance has also been documented in a studied site in Indiana multiple times, and they have appeared consistently as their abundance has aligned. [6]

They can also be baited using pitfall traps containing isopropanol. While the traps attract other insects, it is possible that these traps simply attract carrion beetles by the volatiles produced by carcasses of other insects. However, this is an unlikely explanation. Rather, isopropanol likely acts as a kairomone since there is no differentiation between the preference from females and males. It is possible that isopropanol is perceived as a chemical produced by decomposing bodies during the bloating stage, which would explain why N. americana is attracted to them. [4]

Resource partitioning

N. americana also practices resource partitioning with other silphids such as Oiceoptoma noveboracense and Thanatophilus lapponicus . These three species are reproductively active at different periods of the year. O. noveboracense is active in the early spring, while T. lapponicus is active late in the summer. This resource partitioning behavior has likely evolved due to limitations in resource availability and must be adapted for rapid reproduction. [5]

American carrion beetles on a dead vole.

Life cycle

Larva American Carrion Beetle Larva.jpg
Larva

The American carrion beetle has three instar stages, with differing body measurements at each stage. The first stage has a body length ranging from about 10 to 15 millimeters in length, the second stage ranging from 13 to 21 millimeters in length, and the final stage averaging 23 millimeters in length. The life cycle of the beetle is thought to take around 10 to 12 weeks. [11]

From spring through fall, during daylight, a few hours after flies begin arriving at a carcass, the adult beetles will arrive as well. [3] They immediately begin eating the already hatching fly larvae, mating, and laying their own eggs. As long as the carcass lasts, the adults will remain eating competitors to give their own larvae a chance to eat and grow. Upon hatching from the eggs, the larvae will eat both the carcass and other larvae that are within it. The fly larvae digest part of the carcass, and the beetle larvae will consume the parts that the fly larvae did not, which typically consists of flesh left on the bones and on the moist inside of the face. [5] Eventually the larvae will fall to the ground, dig into the dirt, and pupate. Adults practice overwintering. [2] [3]

The beetle is a ground-dwelling silphid that emerges from its larval state to feed on carcasses in early summer, as its greatest abundance is from June through October. They arrive early during the decomposition process compared to other beetles, which are most prominent during late August. While they do feed on carcasses, they don’t exhibit any signs of parental care. [6]

Protective coloration and behavior

Mimicry

The American carrion beetle displays close mimicry with Psithyrus ashtoni, a cuckoo bumble bee. Both species have a black head, yellow thoracic disk, and a dark pile on their abdomens. The differentiation is that P. ashtoni have less pile on their abdomens. These two species have been confused for each other, with one instance where N. americana was collected instead of P. ashtoni by mistake. There are also other species of carrion beetle that mimic other species of bumble bee. Necrophorus investigator is a mimic of Bombus terrestris and B. lucorum in not only visual characteristics, but also sound.

N. americana’s mimicry is not only limited to morphology; both species also emerge early in the year to begin flight, and they have similar flight patterns. N. americana has a zigzag flight pattern when searching for food, while P. ashtoni has a circular flight pattern which is typically slow and leisurely. Both species are also diurnal, flying highest during the day and lower during the night. The most likely explanations for the evolution of this mimicry are that they can avoid the same predators by sharing their pattern of coloration, and that they can use aposematic coloration to warn predators not to consume them. [7]

Mating

Mate guarding

Some male carrion beetles practice mate guarding, a practice used to increase success from sperm competition. The probability of a beetle guarding is dependent on both the sex ratio and the size of an individual. A larger beetle is more likely to guard than a smaller beetle because smaller beetles require more energy to maintain guarding and are thus unable to compete with larger beetles, so the smaller beetles get little marginal benefit by guarding. In addition, guarding behavior has been observed much more when the sex ratio is male-biased due to increased competition between males. Both of these factors indicate that larger males compete for the largest females and successfully guard them when the ratio is male-biased, which earns the beetle greater paternity and reproductive success compared to smaller males. In equal ratio populations between male and female or female-biased populations, guarding can still be observed, albeit in much lower quantities and for shorter durations. This indicates that males optimize saving energy by guarding as little as possible, but they still expend the necessary energy when intense competition is present. [12]

Mating site

American carrion beetles are rarely found breeding on dung, but an unusual case of this has been documented. A study examining the different types of beetles found in otter scats documented finding 6 N. americana beetles on 3 separate occasions out of 16 beetles, twice discovered to be breeding on the otter scat. This case is also unusual because these beetles are typically only found on medium or larger carcasses as habitats, while otter dung is small (less than 10 cm3). While breeding, the beetles were observed to be standing over the undigested fish parts (bones and scales) in the dung. The multiple occurrences of breeding observed on the dung indicates that otter dung is a beneficial habitat feature for this species. [13]

Mutualism

The beetle is known to engage in mutualistic phoresis with mites of the genus Poecilochirus . Upon arrival at a carcass, these mites drop from the beetle and begin eating the eggs and larvae of the flies that preceded the beetles (and continue to lay more eggs even as the beetles are active). They will eventually return to the adults and be transported to the next carcass. Some of their young will hitch a ride with the beetles' young upon their emergence from the pupal stage. [2]

Forensic significance

N. americana is significant in forensic analyses due to its unique characteristic of feeding on rotting flesh. In comparison to most other flesh-consuming beetles, N. americana is small and has a longer development period, so it is unable to compete with other beetles for superior flesh territories. Thus, it is not found in carcasses in suitcases, which is a superior habitat due to the leakage of organic substances that beetles feed on. Suitcases are also a superior habitat due to the corpses being more easily accessible than other habitats. Rather, in the experiments done, the American carrion beetles were found near sealed drums containing corpses. Drums are an inferior habitat due to the corpse being sealed off from any outside beetles, which means the organic substances are not available to them. American carrion beetles were observed to accumulate around the drums, but did not have access to the corpse itself. Predicting these accumulation patterns is especially important for forensic science since these measures can help determine the minimum postmortem interval (PMI) of a sealed corpse from homicides. N. americana also preferentially consume corpses of larger animals such as pigs (from this study), deer, or potentially humans. [8]

Related Research Articles

<span class="mw-page-title-main">Forensic entomology</span> Application of insect and other arthropod biology to forensics

Forensic entomology is a field of forensic science that uses insects found on corpses to help solve criminal cases. This includes the study of insect types commonly associated with cadavers, their respective life cycles, their ecological presences in a given environment, as well as the changes in insect assemblage with the progression of decomposition. Insect succession patterns are identified based on the time a given species of insect spends in a given developmental stage, and how many generations have been produced since the insects introduction to a given food source. Insect development alongside environmental data such as temperature and vapor density, can be used to estimate the time since death, due to the fact that flying insects are attracted to a body immediately after death, determine any possible movement of the body after death, and the determination of antemortem trauma. The identification of postmortem interval to aid in death investigations is the primary scope of this scientific field. However, forensic entomology is not limited to homicides, it has also been used in cases of neglect and abuse, in toxicology contexts to detect the presence of drugs, and in dry shelf food contamination incidents. Equally, insect assemblages present on a body, can be used to approximate a given location, as certain insects may be unique to certain areas. Therefore, forensic entomology can be divided into three subfields: urban, stored-product and medico-legal/medico-criminal entomology.

<span class="mw-page-title-main">Silphidae</span> Family of beetles

Silphidae is a family of beetles that are known commonly as large carrion beetles, carrion beetles or burying beetles. There are two subfamilies: Silphinae and Nicrophorinae. Members of Nicrophorinae are sometimes known as burying beetles or sexton beetles. 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 such as dead animals. The subfamilies differ in which uses parental care and which types of carcasses they prefer. Silphidae are considered to be of importance to forensic entomologists because when they are found on a decaying body they are used to help estimate a post-mortem interval.

<span class="mw-page-title-main">Burying beetle</span> Genus of beetles

Burying beetles or sexton beetles, genus Nicrophorus, are the best-known members of the family Silphidae. Most of these beetles are black with red markings on the elytra (forewings). Burying beetles are true to their name—they bury the carcasses of small vertebrates such as birds and rodents as a food source for their larvae, this makes them carnivorous. They are unusual among insects in that both the male and female parents take care of the brood.

<span class="mw-page-title-main">Histeridae</span> Family of beetles

Histeridae is a family of beetles commonly known as clown beetles or hister beetles. This very diverse group of beetles contains 3,900 species found worldwide. They can be easily identified by their shortened elytra that leaves two of the seven tergites exposed, and their geniculate (elbowed) antennae with clubbed ends. These predatory feeders are most active at night and will fake death if they feel threatened. This family of beetles will occupy almost any kind of niche throughout the world. Hister beetles have proved useful during forensic investigations to help in time of death estimation. Also, certain species are used in the control of livestock pests that infest dung and to control houseflies. Because they are predacious and will even eat other hister beetles, they must be isolated when collected.

<span class="mw-page-title-main">Trogidae</span> Family of beetles

Trogidae, sometimes called hide beetles, is a family of beetles with a distinctive warty or bumpy appearance. Found worldwide, the family includes about 300 species contained in four or five genera.

<i>Nicrophorus americanus</i> Species of beetle

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 requires carrion to breed. It is also a member of one of the few genera of beetle to exhibit parental care. The decline of the American burying beetle has been attributed to habitat loss, alteration, and degradation, and they now occur in less than 10% of their historic range.

Forensic entomological decomposition is how insects decompose and what that means for timing and information in criminal investigations. Medicolegal entomology is a branch of forensic entomology that applies the study of insects to criminal investigations, and is commonly used in death investigations for estimating the post-mortem interval (PMI). One method of obtaining this estimate uses the time and pattern of arthropod colonization. This method will provide an estimation of the period of insect activity, which may or may not correlate exactly with the time of death. While insect successional data may not provide as accurate an estimate during the early stages of decomposition as developmental data, it is applicable for later decompositional stages and can be accurate for periods up to a few years.

<i>Nicrophorus vespilloides</i>

Nicrophorus vespilloides is a burying beetle described by Johann Friedrich Wilhelm Herbst in 1783. The beetles vary widely in size and can present with a range of anywhere from 12 mm to 20 mm in size. They have two conspicuous orange-yellow bands on the elytra. The color of the antennae are an important distinguishing feature, being totally black. The color of their orange and black markings is multifunctional, as they are conspicuous to avian predators. In general, they present a unique ecological niche, which is their evolution of aposematism, or the strategy they use to warn predators through their conspicuous signals. The wing cases of these beetles possess a squarish shape and are notably shorter in length than their abdomens, indicating a distinct physical characteristic of the species.

<i>Nicrophorus tomentosus</i> Species of beetle

Nicrophorus tomentosus 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 have sensitive antennae that contain olfactory organs. Thus, the beetle can locate dead animals (carcass), and then as the name suggests, can bury them. However, unlike other burying beetles, N. tomentosus does not completely bury these brood carcasses. They instead dig a shallow hole under the carcass and cover it with leaf litter. Recognition of these beetles can be distinguished by its black color with orange markings on the wing covers (elytra).

<i>Nicrophorus nepalensis</i> Species of beetle

Nicrophorus nepalensis, commonly known as a burying beetle, is widespread across tropical and subtropical countries in Asia. It belongs to the order Coleoptera and the family Silphidae, and is part of the nepalensis species-group, which is the second largest species group within the genus Nicrophorus. N. nepalensis differs from some other beetles in that it exhibits biparental care. Its role as a decomposer is crucial in the energy cycle and energy transformation in the ecosystem.

<i>Nicrophorus pustulatus</i> Species of beetle

Nicrophorus pustulatus, also known as the pustulated carrion beetle or blistered burying beetle, is a species of burying beetle that was described by Johann Karl Wilhelm Illiger in 1807. This species is native to North America. N. pustulatus exhibits unique habitat utilization and breeding behaviour relative to other members of the genus. This species may be the only described example of a true parasitoid targeting a vertebrate host.

<i>Nicrophorus interruptus</i> Species of beetle

Nicrophorus interruptus is a species of burying beetle or sexton beetle belonging to the family Silphidae subfamily Nicrophorinae.

<i>Nicrophorus quadripunctatus</i> Species of beetle

Nicrophorus quadripunctatus is a species of burying beetle that predominates in East Asia. First described by German entomologist Ernst Kraatz in 1877, this beetle has since been the subject of much scientific inquiry—particularly concerning its parental care. Like other burying beetles, N. quadripunctatus inhabit small, vertebrate animal carcasses. This environment provides the beetles with the requisite nutrients for themselves and their offspring. To limit resource theft and predation, the carcass is buried underground. For additional protection, a single, dominant male-female pair guards the carcass cooperatively.

<i>Nicrophorus orbicollis</i> Species of beetle

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 decomposer feeding on carcasses of small dead animals. N. orbicollis can be used for scientific research both medically and forensically.

<i>Poecilochirus</i> Genus of mites

Poecilochirus is a Holarctic genus of mites in the family Parasitidae. They are relatively large and often found on rotting corpses, where they are transported by beetles. Deuteronymphs are characterized by two orange dorsal shields and in many species a transverse band on the sternal shield. The juvenile development consists of a larval stage, protonymph, and deuteronymph, but no tritonymph. Females are smaller than males. Males guard female deuteronymphs shortly before these mate, and pairs mate venter-to-venter.

<i>Creophilus maxillosus</i> Species of beetle

Creophilus maxillosus, the hairy rove beetle, is a species of rove beetle.

<i>Oiceoptoma noveboracense</i> Species of beetle

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 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.

<i>Oxelytrum cayennense</i> Species of beetle

Oxelytrum cayennense is a species of carrion beetles belonging to the family Silphidae.

<i>Necrophila</i> Genus of beetles

Necrophila is a genus of carrion beetles, with around 20 species: most found in Asia, and one species in North America, Necrophila americana.

<i>Necrodes littoralis</i> Species of beetle

Necrodes littoralis, also known as the short sexton beetle, is a species of carrion beetle of the genus Necrodes, found in countries across Europe. As a carrion beetle, it feeds on decaying vertebrate remains and maggots. This species' feeding behaviors make it an important asset to forensic entomology.

References

  1. ↑ Species Necrophila americana - American Carrion Beetle: http://bugguide.net/node/view/6744
  2. 1 2 3 Hilton Jr., Bill (May 2004). "Carrion Beetles & Phoretic Mites: Masters of Animal Decomposition". This week at Hilton Pond. Hilton Pond Center for Piedmont Natural History. Archived from the original on 24 July 2008. Retrieved 2008-07-21.
  3. 1 2 3 4 Jason H. Byrd & James L. Castner, ed. (2000-09-28). Forensic Entomology: The Utility of Arthropods in Legal Investigations (2000 ed.). New York: CRC Press. p. 63. ISBN   978-0-8493-8120-1 . Retrieved 2008-07-21.
  4. 1 2 3 Reut, Michal; Cowell, Brian; Pszczolkowski, MacIej (2010-09-01). "Traps baited with isopropanol attract the American Carrion Beetle, Necrophila americana (L.) (Coleoptera: Silphidae)". Coleopterists Bulletin. doi:10.1649/0010-065X-64.3.230.8.
  5. 1 2 3 4 Anderson, Robert S. (1982-06-01). "Resource partitioning in the carrion beetle (Coleoptera:Silphidae) fauna of southern Ontario: ecological and evolutionary considerations". Canadian Journal of Zoology. 60 (6): 1314–1325. doi:10.1139/z82-178. ISSN   0008-4301.
  6. 1 2 3 Owings, Charity G.; Picard, Christine J. (2015). "Temporal Survey of a Carrion Beetle (Coleoptera: Silphidae) Community in Indiana". Proceedings of the Indiana Academy of Science. 124 (2): 124–128. ISSN   2380-7717.
  7. 1 2 Fisher, R. M., & Tuckerman, R. D. (1986). Mimicry of Bumble Bees and Cuckoo Bumble Bees by Carrion Beetles (Coleoptera: Silphidae). Journal of the Kansas Entomological Society, 59(1), 20–25. http://www.jstor.org/stable/25084730
  8. 1 2 Lutz, Lena; Amendt, Jens; Moreau, Gaétan (2018-10-01). "Carcass concealment alters assemblages and reproduction of forensically important beetles". Forensic Science International. 291: 124–132. doi:10.1016/j.forsciint.2018.08.014. ISSN   0379-0738.
  9. ↑ Ratcliffe, Brett. (1996). The carrion beetles (Coleoptera: Silphidae) of Nebraska. Bulletin of the University of Nebraska State Museum. 13. 1-100.
  10. ↑ Lingafelter, S. W. (1995). Diversity, Habitat Preferences, and Seasonality of Kansas Carrion Beetles (Coleoptera: Silphidae). Journal of the Kansas Entomological Society, 68(2), 214–223. http://www.jstor.org/stable/25085584
  11. ↑ Watson, E. J., & Carlton, C. E. (2005). Succession of Forensically Significant Carrion Beetle Larvae on Large Carcasses (Coleoptera: Silphidae). Southeastern Naturalist, 4(2), 335–346. http://www.jstor.org/stable/3877967
  12. ↑ "Size, operational sex ratio, and mate-guarding success of the carrion beetle, Necrophila americana". academic.oup.com. Retrieved 2024-04-04.
  13. ↑ "Attraction of adult Silphidae and Staphylinidae (Coleoptera) to river otter latrines". Journal of the Acadian Entomological Society.
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