Gravedigger beetles don't look away when carrion is lying around in the forest and field. Carcasses are buried with combined forces and recycled as a breeding station for the offspring. Ingenious collaborations and preservation techniques slow down decomposition. A compact profile lists the breathtaking characteristics of carrion beetles. We invite you to a fascinating journey through the blessed life of an ecological jewel on six legs.
Why are gravedigging beetles useful?
Gravedigger beetles are useful insects that dispose of carrion like dead small animals and use it as a breeding ground for their larvae. They contribute to the natural optimization of nature and also eat rotting plant material and pests.
- Gravedigger beetles are elongated-oval, 12-26 mm large, black with two red-yellow cross bands with a zigzag pattern on the cover wings (with the exception of black gravediggers)
- Common Gravedigger and Black Gravedigger have red-yellow antennae. Black-horned gravedigger has black antennae
- Gravediggers are valuable beneficial insects because the carrion beetles use carcasses as a source of food and breeding grounds
Gravedigger Beetle – Profile
Gravedigger beetles are very useful insects
Scientists couldn't have chosen a more apt name. Gravedigger beetles are nature's undertakers because they diligently dispose of carrion. Carcasses up to the size of a mouse are not only buried, but expertly processed and reused as a food source and breeding ground for their larvae.
| Gravedigger | Common Gravedigger | Black Gravedigger | Black-horned Gravedigger |
|---|---|---|---|
| Size | 12-22mm | 18-26mm | 12-18mm |
| color | black | black | black |
| Top wing | red-yellow, jagged cross bands | black | red-yellow jagged cross bands |
| Antenna Clubs | red-orange | red-orange | black |
| Food | Carrion | Carrion | Carrion |
| Activity | diurnal | diurnal | diurnal |
| Botanical name | Nicrophorus vespillo | Nicrophorus humator | Nicrophorus vespilloides |
| Family | carrion beetle | carrion beetle | carrion beetle |
| Occurrences | Asia, Europe to Finland | Asia, Europe to southern Scandinavia | Asia, Europe to British Isles |
The gravedigger beetle underpins its nimbus as a beneficial insect with other food preferences. The species found in Europe happily destroy rotting plant material and hunt insects and larvae. The prey pattern includes a number of pests that make life difficult for hobby gardeners in the garden, on the balcony and on the terrace.
Excursus
A rare guest in the apartment
Every now and then a gravedigger beetle wanders into an apartment. This usually happens in the dark season, when artificial light causes the beetles to lose their orientation and get into the house. This is no cause for concern because gravediggers are not poisonous and do not bite or sting. Cut off from its natural food sources, this disaster means a death sentence for the beneficial insect. Once you have properly admired the rare guest, please initiate a rescue operation using the glass trick. Because gravedigger beetles are not as agile as other beetles in the home, you can easily place a glass over the insect. Now slide a piece of cardboard or double-folded paper underneath, carry your guest outside and let him go.
Ecologically beneficial propagation method
Gravedigger beetles practice a fascinating reproduction strategy to benefit nature. The following overview attempts to present the complex process in comprehensible steps. Join us as we start a sophisticated family in the kingdom of the carrion beetles:
Breeding site search
Mating season is in May
From May onwards, male gravediggers start looking for dead small animals as the optimal breeding site. Small rodents such as voles or moles as well as birds are primarily considered. Beetle masters who have found what they are looking for attract females who are ready to mate. The celebrated courtship ritual is called Sterzeln. The male seductively stretches his backside into the air and wiggles it promisingly. If competing males appear, attracted by the smell of carrion, territorial fights will ensue to clarify ownership rights. Female gravediggers, however, are welcome and will not be attacked.
Mating and laying eggs
Immediately after mating, the expectant beetle parents dig a cavity under the carcass, which then begins to sink. After six hours, the animal corpse is already underground and after 30 hours it has reached its final position in the crypt. During this work, hair or feathers are removed and the carrion takes on a spherical shape.
Starting from the crypt, the female digs a mother tunnel and lays the eggs in it. Egg laying never takes place directly in carrion. The lady beetle then eats a crater in the carcass, the so-called eating crater. Here the female waits patiently for the first larva to hatch.
Larvae hatching and brood care
Carcasses serve as food and breeding grounds
Within a few hours, the larvae hatch from the eggs and wander unerringly towards their mother. To help with orientation, she has carefully marked the breeding site with scents. During the first two molts, the offspring are fed mouth-to-mouth by both parents. After the second molt, the larvae have sufficiently strong mouthparts to feed on the carcass themselves. In addition, feeding continues to meet the high energy requirements of the rapidly growing larvae. The larval development, with a total of three molts, extends over a period of 4 to 6 days, closely accompanied by the intensive brood care of the adult beetles.
The larvae then leave the breeding site to burrow into the ground some distance away and pupate there. Another 14 days pass until the finished gravedigging beetles leave their pupal cradle. All that remains of the carcass is an empty shell.
Tip
Gravedigger beetles are real chatterboxes. The beetles communicate constantly using chirping noises during the strenuous work of burying a carcass and the grueling care of the brood. Anyone who hikes through nature with open ears has a good chance of listening to gravedigging beetles and admiring them at work.
Dream Team of the Forest – Gravediggers and Mites
Gravedigger beetles gain an advantage over food competitors by burying their prey with combined strength. This process takes a long time, which flies use to lay their eggs on the carcass. This is where mites come into play, with the help of clever gravediggers to thwart the competition. The following overview summarizes how the plan works:
- Gravedigger beetle sniffs out dead mouse
- Beetle walks over the carcass and lifts it to check size and weight as a potential breeding site
- Mites brought with them change from the beetle to the carcass to destroy fly eggs
Result of this win-win symbiosis: Mites can be easily transported to the food source by the beetle taxi. No voracious maggots develop on the carcass and the beetle larvae eat away the supplies.
In the following video you can watch in impressive images how a black-horned gravedigger transports mites as passengers to the carrion.
Schwarzhoerniger Totengraeber (Nicrophorus vespilloides)
Ingenious preservation – gravedigger beetle slows down decomposition
The use of mites as a cleaning crew against fly eggs is not enough for the gravedigger beetle to protect the breeding chamber. In order to slow down decomposition, the carcass is expertly prepared. The clever beetles have the body's own preservatives on board, as curious entomologists from the Max Planck Institute in Jena discovered.
An animal corpse that has been cleaned of hair and processed into a ball of meat receives a special treatment with secretions. This cocktail makes the breeding chamber last longer. During this process, gravediggers cover the food with a film of bacteria and yeast. The anti-microbial substance is produced in the intestines of the carrion beetles and sprayed onto the carcass. As a result, decomposition slows down, important nutrients are retained and the formation of toxic carcass substances is prevented.
Frequently asked questions
I have a gravedigger beetle running around my apartment. What to do?
There is no need to worry because the beetle has just lost its way. Please capture the involuntary guest alive. Ideally, you should have a live insect trapping device on hand for this purpose. Alternatively, arm yourself with a glass and a piece of cardboard. Place the glass over the beetle. Slowly push the cardboard under the glass, carry the glass prison and its inmates outside and release the gravedigger into freedom.
Are burying beetles poisonous to people or pets?
Gravedigger beetles are not dangerous to humans or animals
No, gravedigger beetles pose no danger to people or pets. The beetles do not bite and have no stingers. On the contrary, carrion beetles make themselves useful as he alth police because they dispose of animal carcasses and eat rotting plant material. In addition, gravediggers prey on other insects and larvae, including a number of biting and stinging pests.
What does a gravedigger beetle look like?
A gravedigger beetle is 12 to 22 cm long. Its elongated oval body is black. The cover wings are decorated with two wide, orange-yellow transverse bands with a zigzag-shaped border. The wing coverts, pronotum and abdominal edges are hairy light yellow. The color of the antennae clubs differs depending on the species. In the black-horned gravedigger (Nicrophorus vespilloides) the antennae are uniformly black. Common burying beetle (Nicrophorus vespillo) and black burying beetle (Nicrophorus humator) boast red-orange antennae.
What lower classification of gravedigger beetle is there?
The gravedigger beetle genus is represented by 70 species worldwide. The three species that are primarily relevant for Europe as a lower classification are the common gravedigger (Nicrophorus vespillo), the black gravedigger (Nicrophorus humator) and the black-horned gravedigger (Nicrophorus vespilloides). The largest native gravedigger species called Nicrophorus germanicus with a body length of up to 30 millimeters is rarely found.
Where can you find gravedigging beetles?
Gravedigger beetles are present wherever there are dead small animals lying around. The carcasses are easiest to bury in loose forest soil for use as a breeding chamber and food source. The best chances of meeting the unique carrion beetles are in the forest, preferably on the sunny edge of the forest.
Tip
Exemplary teamwork among gravedigging beetles goes beyond loving brood care. Researchers from the American National Academy of Sciences observed that parentless burying beetle larvae hold tightly together. If neither parent serves the food in a bite-sized manner, the larvae work together to process the meat until it is suitable for consumption. It's not just the biological siblings who benefit from this phenomenal cooperation. Abandoned larvae from neighboring gravedigger families are also integrated into the team.
