Carrion Beetle: All You Need to Know for Nature Enthusiasts

Carrion beetles are fascinating insects known for their unique ecological role in consuming dead and decaying animals.

These beetles, belonging to the family Silphidae, play an essential part in recycling nutrients and speeding up the decomposition process in nature.

There are a variety of carrion beetles, with the American burying beetle (Nicrophorus americanus) being the largest in North America.

American Carrion Beetle

This species reaches 1.0 to 1.8 inches in length and displays a distinctive orange-red on shiny black coloration.

Another common species is the American carrion beetle (Necrophila americana), known for its yellow pronotum with a black spot in the middle, and an adult length of about ½ to ¾ inch.

Carrion beetles serve as nature’s “clean-up crew” by consuming the remains of deceased animals. Additionally, they can help control the population of other insects, such as fly maggots, which also thrive on decomposing organisms.

Overall, carrion beetles hold a significant place in the ecosystem and should be appreciated for their important role.

Carrion Beetle Overview

Family Silphidae

Carrion beetles belong to the family Silphidae and are known for their unique behavior of feeding on decaying organic matter, such as dead animals.

Notable examples of this family include the American burying beetle (Nicrophorus americanus) and the European carrion beetle.

Size

Sizes vary between various species of carrion beetles.

The American carrion beetle (Necrophila americana) and the American burying beetle (Nicrophorus americanus) are both part of the Silphidae family.

The American burying beetle is the larger of the two, ranging from 1.0 to 1.8 inches (25 to 35 centimeters) in length¹.

Meanwhile, the American carrion beetle is smaller, with adults between ½ to ¾ inches in length².

Color

Both types of beetles are predominantly black, with contrasting features.

The American burying beetle often has red, orange, or yellow markings, while the American carrion beetle has a distinct yellow pronotum (the plate-like structure that covers the thorax) with a large, central black spot².

American Carrion Beetle

Shape

Carrion beetles are generally flattened, with the American carrion beetle resembling a bumblebee while in flight².

The shell-like forewings (elytra) in both beetles have a distinct pattern, narrower toward the front and wider toward the end of the body³.

Antennae

The antennae of carrion beetles are often clubbed, with several segments at the end forming a distinctive ball-like structure.

This feature allows them to better detect odors associated with carrion, helping with their scavenging lifestyle.

Elytra

As mentioned earlier, the elytra in carrion beetles are wider toward the end of the body and narrower toward the front³.

In many species, their elytra are too short to cover the entire abdomen, leaving the hind wings exposed.

Pronotum

A key feature to differentiate between American burying and carrion beetles is the pronotum.

The American burying beetle usually has a black pronotum, while the American carrion beetle has a yellow one with a large, black central spot².

Comparison Table: American Burying Beetle vs American Carrion Beetle

Feature	American Burying Beetle	American Carrion Beetle
Size	1.0 to 1.8 inches	½ to ¾ inches
Color	Black with red, orange, or yellow markings	Black with yellow pronotum and black spot
Shape	Flattened body	Flattened body, resembles bumblebee in flight
Antennae	Clubbed at the end	Clubbed at the end
Elytra	Shell-like, wider at the end	Shell-like, wider at the end
Pronotum	Black	Yellow with black central spot

Distribution and Habitat

Carrion beetles are distributed across various continents and can be found in diverse habitats where decaying organic matter is present.

For instance, the American burying beetle was once widespread across North America, but its populations have declined, and it is now listed as endangered in the U.S.

European carrion beetles are native to Europe but have also been found in North America over time.

Biology and Behavior

Life Cycle

Carrion beetles go through a complete metamorphosis consisting of four stages: egg, larva, pupa, and adult.

Female beetles typically lay their eggs near a suitable food source, such as a carcass or rotting fruit.

The larvae hatch from the eggs and begin feeding on the food source alongside any competing maggots present.

The carrion beetle larvae are teardrop-shaped, black grubs that somewhat resemble sowbugs¹.

After consuming enough food, the larvae fall to the ground and burrow into the soil where they pupate².

The adult carrion beetles emerge from the pupae and continue to forage for food, contributing to the ecosystem as scavengers.

Carrion Beetle Larva

Diet and Carrion Utilization

Adult carrion beetles primarily feed on:

• Carcasses of small animals ( e.g., rodents, birds)
• Insects (especially fly maggots)
• Rotting fruit and vegetation

They play a crucial role in the ecosystem by helping to recycle nutrients and decompose animal carcasses³.

In addition to their diet, some carrion beetle species aid in burying carcasses, such as the American burying beetle, which can measure up to 1.8 inches in length.

Here’s a comparison table of two well-known carrion beetle species:

Species	Size	Coloration	Diet and Behavior
American Burying Beetle	1.0 to 1.8 in	Black and orange markings	Buries carcasses/subterranean; feeds on fly larvae, carrion
American Carrion Beetle	0.5 to 0.75 in	Yellow and black markings	Dwells under large carcasses; feeds on fly maggots, carrion1

Nocturnal Activity

Carrion beetles are primarily nocturnal creatures. They scavenge for food in the evening, guided by the sense of smell from their antennae.

They prefer to remain in damp, dark habitats like forests, using their strong sense of smell to locate food sources⁴.

To summarize, here are some notable nocturnal habits of carrion beetles:

• Attracted to lights, which can sometimes lead them into human habitats
• Rely on olfactory cues from decomposing matter and carcasses
• More active during warmer months, when food sources are more abundant

Flight

Carrion beetles are capable of flight. These beetles are equipped with two pairs of wings, like most other beetles.

The front pair, known as elytra, are hard and protective, covering the more delicate hind wings which are used for flying.

The elytra open up to allow the hind wings to unfold when the beetle decides to take flight.

Carrion Beetle Wings

Carrion beetles utilize their flying ability to move between different locations in search of food sources, primarily decaying animal matter.

Flying enables them to cover greater distances and find suitable environments for laying their eggs and continuing their life cycle.

While they are not renowned for their flying skills compared to other insects, their ability to fly plays a crucial role in their survival and ecological contributions.

Predators

Carrion beetles have various predators, including birds, mammals, and other insect-eating creatures.

Seasons Active

Carrion beetles are active across different seasons, and their presence varies depending on habitat, abiotic factors, and geographic location. 

Interaction with Ecosystem

Decomposers and Ecological Role

Carrion beetles play a vital role in ecosystems as decomposers.

They break down dead animals, returning nutrients to the soil. Some key carrion beetles include:

• Necrodes
• Silpha
• Dendroxena
• Necrophila

These beetles also help control insect populations because their larvae feed on maggots of flies that compete with beetle larvae.

Interactions with Other Species

Mutualistic Relationship with Mites

Carrion beetles share a fascinating mutualistic relationship with mites.

Mites hitch a ride on the beetles to new food sources, such as decaying carcasses, where they:

• help the beetle by consuming fly eggs
• benefit themselves by gaining access to food

This relationship helps both species to thrive and reduces competition for resources.

Competition with Flies

Carrion beetles face competition from other decomposers, primarily flies.

Both beetle larvae and fly larvae rely on the same decaying organic matter for nourishment. However, carrion beetles have a few advantages:

• ability to feed on fly eggs, reducing fly population
• removal of unwanted by-products from decomposition

Role in Forensic Entomology

Carrion beetles have a significant role in forensic entomology, the study of insects in criminal investigations.

As beetles arrive at different stages of decomposition, they can provide valuable information.

For example, determining the time since death, or post-mortem interval (PMI).

Species	Role in Forensic Entomology
Carrion Beetles	Help determine time since death by analyzing their arrival at the scene
Nicrophorus	Aid in locating buried remains, as they are attracted to deeper carcasses

In conclusion, carrion beetles have complex interactions with mites, flies, and play an important role in forensic entomology.

Understanding these relationships helps us appreciate their role in the ecosystem and their application in criminal investigations.

Pollination

In some cases, these beetles also participate in plant pollination.

The Liceoptoma carrion beetles have been observed pollinating yucca plants², which evolved a special mechanism to attract the beetles.

The yucca flowers emit a scent that mimics the smell of rotting flesh, attracting beetles that crawl into the flowers, inadvertently pollinating them.

To summarize, carrion beetles perform some very important roles in the ecosystem

• Decompose dead animals, recycling nutrients
• Control insect populations, reducing competition for resources
• Can be pollinators for some plant species

Pustulated Carrion Beetle

Types and Variation

Burying Beetles

Burying beetles, also known as Nicrophorus, are a prominent group of carrion beetles. They are characterized by:

• A distinct color pattern: black with red, orange, or yellow markings
• Unique elytra: wider towards the end, narrower towards the front

Some notable species include:

• American burying beetle (Nicrophorus americanus)
• Nicrophorus vespilloides
• Nicrophorus humator
• Nicrophorus investigator

Burying Beetle with Phoretic Mites

Sexton Beetles

Sexton beetles belong to the genus Nicrophorus and are similar to burying beetles. They can be identified through their:

• Antennae: with a club-like structure at the tips
• Abdomen: exposed 1 to 3 segments due to short elytra

An example of a sexton beetle species is Nicrophorus vespilloides.

Red-Breasted Carrion Beetle

The red-breasted carrion beetle, scientifically known as Oiceoptoma thoracicum, has unique features:

• A red thorax: distinguishing it from other carrion beetles
• Fondness for fungi: unlike burying and sexton beetles

Feature	Burying Beetles	Sexton Beetles	Red-Breasted Carrion Beetle
Color	Black, red, orange, yellow markings	Similar to burying beetles	Black with red thorax
Elytra	Wider at the end, narrower at the front	Short, exposing the abdomen tip	Standard
Diet	Carrion, maggots	Carrion, maggots	Carrion, maggots, fungi

These carrion beetles play a vital role in ecosystems by decomposing dead animals and controlling insect populations, with each group having unique characteristics suited to their ecological niches.

Conservation Efforts and Threats

Endangered Species and Conservation Measures

Some species of carrion beetles are facing decline, mainly due to habitat loss and destruction.

Entomologists are actively working on conservation measures to protect these vital insects.

For instance, Nicrophorus investigator is one of the rare endangered species in the UK. Another one is the Nicrophorus americanus, which is native to America.

The threats these beetles face include:

• Habitat destruction
• Light pollution
• Fragmented populations

Conservation measures taken for carrion beetles include:

• Restoration of suitable habitats
• Limiting light pollution
• Encouraging landowners to create beetle-friendly environments

Nicrophorus investigator

Reintroduction Efforts

Reintroduction efforts play a significant role in the conservation of endangered carrion beetles such as the American burying beetle.

These large, predatory beetles have a relatively short lifespan, making them ideal candidates for reintroduction programs.

These programs usually involve the following stages:

1. Captive breeding of the beetles
2. Release of the beetles into suitable habitats
3. Monitoring the released beetles’ populations

Reintroducing the beetles helps establish stable populations and supports overall woodland health.

Conclusion

Carrion beetles, with their unique ecological roles and fascinating behaviors, are indispensable components of our ecosystems.

They contribute significantly to nutrient recycling and natural decomposition processes, aiding in maintaining ecological balance.

Understanding their life cycle, interactions, and the conservation challenges they face allows us to appreciate their importance and the need to protect these often-overlooked creatures.

Their presence, though sometimes unnoticed, has far-reaching impacts on the environment and the intricate web of life.

 

Footnotes

1. https://mdc.mo.gov/discover-nature/field-guide/american-carrion-beetle ↩ ↩² ↩³

2. https://extension.umaine.edu/home-and-garden-ipm/fact-sheets/common-name-listing/american-carrion-beetle/ ↩ ↩²

3. https://education.mdc.mo.gov/discover-nature/field-guide/carrion-beetles-burying-beetles ↩

4. https://mdc.mo.gov/discover-nature/field-guide/carrion-beetles-burying-beetles ↩