View of N. tomentosus under a microscope. Note the characteristic golden setae on the pronotum.
KEEP CALM AND CARRION
Eww, what's that smell?! When you see an animal carcass, you might immediately think of death and decay, but closer inspection will show that dead animals can actually support the lives of many small organisms, such as necrophagous insects (those that feed on dead flesh) and predators that feed on these insects. One of the most charming diners in this group is Nicrophorus tomentosus.
DIAGNOSTICS
Nicrophorus tomentosus, the gold-necked or tomentose burying beetle, is a member of the carrion-beetle family, Silphidae. This beetle is very easy to identify, and is not easily confused with other species. Like other members of its genus, it has short, rectangular elytra (tough, shell-like front wings) that terminate before the tip of the abdomen, and is mostly black with rough orange-red stripes. The header photo above shows some of the variation in marking shade exhibited by this species. It is a relatively large beetle, ranging in length from about 11 mm to 20 mm. Although members of the genus can be distinguished by their variable orange markings and patterns, the easiest way to identify N. tomentosus is by the characteristic golden-brown setae ("hair") on its pronotum, which is the segment behind its head. Other members of the genus have hairless pronotums, so this makes identifying this species a piece of cake!
LIFE HISTORY
The life history of the tomentose burying beetle is complex and extremely fascinating. Their story begins when an animal dies. Not just any animal will suffice, however, as burying beetles are only attracted to small carcasses, such as those of mice, voles, shrews, and birds. In most members of the Nicrophorus, when a mating pair of beetles locates one of these small cadavers, they will dig a hole in the ground and bury it entirely under soil. N. tomentosus is somewhat unique in that it's one of the few species that digs a shallow pit under the carcass, and then covers it back up with leaf litter, rather than soil. Once the dead animal is concealed, the beetles will remove its fur or feathers, and then coat it in a film of antimicrobial saliva and other secretions until it forms a ball. The female will then lay her eggs on the ball of flesh and raise her young, usually with some help from the father. This parental care can involve defending the larvae from potential predators and providing food via regurgitated flesh (sounds tasty, right?). This behavior is fascinating because parental care is unusual in insects, and biparental care (care from both the mother and father) is particularly rare. Below is a video of another member of Nicrophorus preparing a shrew carcass for its young.
Eww, what's that smell?! When you see an animal carcass, you might immediately think of death and decay, but closer inspection will show that dead animals can actually support the lives of many small organisms, such as necrophagous insects (those that feed on dead flesh) and predators that feed on these insects. One of the most charming diners in this group is Nicrophorus tomentosus.
DIAGNOSTICS
Nicrophorus tomentosus, the gold-necked or tomentose burying beetle, is a member of the carrion-beetle family, Silphidae. This beetle is very easy to identify, and is not easily confused with other species. Like other members of its genus, it has short, rectangular elytra (tough, shell-like front wings) that terminate before the tip of the abdomen, and is mostly black with rough orange-red stripes. The header photo above shows some of the variation in marking shade exhibited by this species. It is a relatively large beetle, ranging in length from about 11 mm to 20 mm. Although members of the genus can be distinguished by their variable orange markings and patterns, the easiest way to identify N. tomentosus is by the characteristic golden-brown setae ("hair") on its pronotum, which is the segment behind its head. Other members of the genus have hairless pronotums, so this makes identifying this species a piece of cake!
LIFE HISTORY
The life history of the tomentose burying beetle is complex and extremely fascinating. Their story begins when an animal dies. Not just any animal will suffice, however, as burying beetles are only attracted to small carcasses, such as those of mice, voles, shrews, and birds. In most members of the Nicrophorus, when a mating pair of beetles locates one of these small cadavers, they will dig a hole in the ground and bury it entirely under soil. N. tomentosus is somewhat unique in that it's one of the few species that digs a shallow pit under the carcass, and then covers it back up with leaf litter, rather than soil. Once the dead animal is concealed, the beetles will remove its fur or feathers, and then coat it in a film of antimicrobial saliva and other secretions until it forms a ball. The female will then lay her eggs on the ball of flesh and raise her young, usually with some help from the father. This parental care can involve defending the larvae from potential predators and providing food via regurgitated flesh (sounds tasty, right?). This behavior is fascinating because parental care is unusual in insects, and biparental care (care from both the mother and father) is particularly rare. Below is a video of another member of Nicrophorus preparing a shrew carcass for its young.
A photo of one of the N. tomentosus I found on Cornell's campus. One of the mutualistic mites is riding on its elytra.
COOPERATION AND MUTUALISM
Because N. tomentosus covers its carcasses close to the ground surface, it faces the risk of other necrophagous insects, especially flies, taking over. To combat this, this species is one of few burying beetles that will occasionally form small "colonies" on a single carcass. In other species of Nicrophorus, the first arrivals at a fresh carcass will compete for its ownership, and the dominant male and the dominant female will use it for their young. However, in N. tomentosus, it's not rare for several mating pairs, or just the females, to raise their young on the same body. This allows more females to defend the area, thus decreasing the likelihood of predation and competition from other necrophagous insects.
Another way that N. tomentosus combats the risk of maggots stealing their food is by taking part in a mutualistic relationship with a small, pale pink or orange mite belonging to the genus Poecilochirus. These mites are very common on N. tomentosus, so if you find this species of beetle, you're also likely to find some of the mites! This relationship is beneficial for both parties because the mites can consume fly eggs, as well as microbes on the carcass, and the beetles transport the mites from one food source to another. Usually a handful of mites can be found on an adult beetle, but some individuals can carry several dozen of them at once!
COOPERATION AND MUTUALISM
Because N. tomentosus covers its carcasses close to the ground surface, it faces the risk of other necrophagous insects, especially flies, taking over. To combat this, this species is one of few burying beetles that will occasionally form small "colonies" on a single carcass. In other species of Nicrophorus, the first arrivals at a fresh carcass will compete for its ownership, and the dominant male and the dominant female will use it for their young. However, in N. tomentosus, it's not rare for several mating pairs, or just the females, to raise their young on the same body. This allows more females to defend the area, thus decreasing the likelihood of predation and competition from other necrophagous insects.
Another way that N. tomentosus combats the risk of maggots stealing their food is by taking part in a mutualistic relationship with a small, pale pink or orange mite belonging to the genus Poecilochirus. These mites are very common on N. tomentosus, so if you find this species of beetle, you're also likely to find some of the mites! This relationship is beneficial for both parties because the mites can consume fly eggs, as well as microbes on the carcass, and the beetles transport the mites from one food source to another. Usually a handful of mites can be found on an adult beetle, but some individuals can carry several dozen of them at once!
Source: https://bugguide.net/node/view/28744/data
RANGE AND HABITAT
Nicrophorus tomentosus is a relatively common, widespread species. It occurs in parts of Canada, and in the United States, its range occurs from the Atlantic border west to Utah and Colorado, and from the Canadian border south to Georgia. To the right is a map of sightings posted to a popular website, BugGuide. Note that some states, such as Illinois, Delaware, and Kentucky have sightings recorded on other sites, such as iNaturalist, but not here.
This species' habitat includes woodlands and surrounding areas. Since this group uses leaf litter to cover its brood chambers, it frequents areas where deciduous trees are abundant. I found mine on a dead mole I left outside of my apartment, which is located in a lightly wooded suburb.
Adults of this species are most typically found from June to October.
Nicrophorus tomentosus is a relatively common, widespread species. It occurs in parts of Canada, and in the United States, its range occurs from the Atlantic border west to Utah and Colorado, and from the Canadian border south to Georgia. To the right is a map of sightings posted to a popular website, BugGuide. Note that some states, such as Illinois, Delaware, and Kentucky have sightings recorded on other sites, such as iNaturalist, but not here.
This species' habitat includes woodlands and surrounding areas. Since this group uses leaf litter to cover its brood chambers, it frequents areas where deciduous trees are abundant. I found mine on a dead mole I left outside of my apartment, which is located in a lightly wooded suburb.
Adults of this species are most typically found from June to October.
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FUN FACTS
REFERENCES “American Burying Beetle (Nicrophorus Americanus).” Environmental Conservation Online System, U.S. Fish and Wildlife Service. Web. 27 Nov. 2017. Brown, J., & Wilson, D. (1992). Local Specialization of Phoretic Mites on Sympatric Carrion Beetle Hosts. Ecology. 73(2), 463-478. Hall et al. (2013). Description of Acoustic Characters and Stridulatory Pars Stridens of Nicrophorus (Coleoptera: Silphidae): A Comparison of Eight North American Species. Annals of the Entomological Society of America. 106. 661-669. 10.1603/AN13001. Scott, M. P. (1994). Competition with flies promotes communal breeding in the burying beetle, Nicrophorus tomentosus. Behavioral Ecology and Sociobiology. 34(5), 367-373. Video: https://www.youtube.com/watch?v=Ua1wC59phpk |
Webpage, photographs, and beetle illustration by Arabelle Osicky.
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