American Burying Beetle
|Geographical Range||Midwestern United States, Texas and Rhode Island|
|Habitat||Savannahs, prairies, grasslands|
|Scientific Name||Nicrophorus americanus|
|Conservation Status||Critically endangered|
The American burying beetle is named for its practice of burying its food, carrion (dead animals). The beetle uses special chemical receptors in its antennae to detect dead meat. These receptors are so sensitive that they pick up the carcass' signal from a long distance and very quickly - usually within an hour after the animal's demise.
American burying beetles are the largest of the carrion beetles: up to one-and-a-half inches long. They are shiny black with bright orange-red bands on their elytra (wing-covers). They also have a bright orange-red patch just behind the head and a patch between the eyes.
Carrion: Size Matters
What type of carrion do American burying beetles like to eat? They aren't picky. Insects, mice, voles, opossums, birds, snakes, fish - they all show up on the beetles' menu.
What the beetles do with a particular carcass depends on its size. If it's fairly small, the adult beetles will eat it themselves. If it's relatively large, they'll use it as food for their young.
When the beetles detect a good-sized piece of dead meat, they fight for it. The winners -- a male and female pair -- move the carcass to a suitable site and bury it. Within the nesting chamber they prepare the carrion, removing its hair or feathers. They also coat the carcass with preservatives - secretions from their mouth and anus. Now it's ready to be baby food!
The female beetle lays her eggs near the preserved carcass. Within four days, the eggs hatch into larvae. (Caution: Readers with weak stomachs, don't read on!) The parents move the little larvae to the carcass, where the larvae ask to be fed by stroking the parents' mandibles (part of the mouth). Both parents feed their offspring by eating some of the dead flesh and regurgitating it into the larvae's mouths. This goes on for about six to 12 days, until the larvae begin their next stage of development, pupation (see Invertebrates).
After 48 to 60 days, the new adults emerge from pupation. Now the circle of life begins again.
Where Have All the Beetles Gone?
About 100 years ago, American burying beetles were found in 35 states (including Missouri) and southern Canada. Today, they are known to exist only in Rhode Island, Texas, and five Midwestern states (Kansas, Oklahoma, South Dakota, Nebraska, and Arkansas). They haven't been seen in Missouri since 1980.
What caused the beetles' decline? Habitat loss is thought to be one cause. When people altered the landscape (for farming and development), it changed the species that lived there. There were fewer animals that served as the beetles' food, even as there were more carrion feeders to compete with the beetles. Besides habitat change, pesticides may have played a part in the beetles' decline. As a result, the "U.S. Fish and Wildlife Service" now lists the American burying beetle as a federally protected endangered species.
The Saint Louis Zoo has been active in the conservation of the American burying beetles. We recently succeeded in breeding more than 1,000 new beetles! See how we're helping the little guys and are now working on returning some of our hatchlings back to the wild.
Why Should We Care?
American burying beetles are among the many small critters that decompose (break down) the bodies of dead animals and plants. Without these decomposers, we'd be up to our eyeballs in dead stuff!
Is anything being done to help American burying beetles? Yes! Conservation efforts include surveys, to determine if the beetles still exist in states where they once lived; monitoring programs, to see how well the beetles are doing in states where they're known to occur; and captive breeding and reintroduction programs. Though there is reason for hope, the American burying beetle still has a long way to go to recover.
- American burying beetles are nocturnal (active at night). The nighttime temperature must be above 60° F before they begin their amazing parental behavior.
- American burying beetles carry on their body large numbers of tiny mites. Sound creepy? It's really not. These mites help keep the beetles and their carrion meals free of microbes and fly eggs.
- Adults of the species live for about four to six months after pupation.