Window on Nature
By Lowell & Kaye Christie, F47246
Wasn’t it nice of Mother Nature to provide a cleanup crew? It certainly makes walking and hiking a lot better without the remains of critters underfoot. Many readers are likely familiar with black vultures and turkey vultures soaring above, looking for something to eat. Once they spot a carcass, they land and begin cleaning up the mess. At the other end of the size spectrum lie the tiny burying beetles, which take care of small dead creatures, such as birds, squirrels, chipmunks, mice, and rats.
Burying beetles are insects most of us have never seen, and probably never will. Like vultures, these beetles eat meat, and they even store up provisions to feed their offspring.
Would you expect a beetle to have elaborate parenting instincts? Ants, wasps, and honeybees, yes “” but beetles? In fact, American burying beetles, also known as giant carrion beetles, are very attentive parents. Note the plural “” both parents work hard to raise their young.
The American burying beetle requires a larger carcass than similar burying insects, and they find that dead quail or pheasant chicks are about the right size to last through a breeding season. But they’re quite willing to dine on other creatures.
The prospective parents can’t afford to wait until their babies arrive before they work out how to feed them. The parents-to-be start storing food even before the eggs are laid, and they stockpile enough to feed the family until their offspring can survive independently.
Since rodents live just about everywhere, we’ll use a mouse to illustrate the food gathering and storing process.
Typically, a male beetle waits until dark before searching for food, in this case a dead mouse. (Our beetle friends aren’t up to snatching a live one.) Once the beetle finds a carcass, he begins emitting pheromones to catch the attention of a mate.
Then the couple “” a male and a female burying beetle “” gets to work. Their first task is to bury the carcass before some other critter barges in. Luckily, these beetles are terrific diggers, able to scrape out the soil beneath the corpse to gradually lower it underground. The pair has to work fast; it’s important to get the “food” hidden before daylight brings hungry robbers nosing around.
When the carcass is safely belowground, the beetles begin separating the flesh from the bones, and shaping it into a tightly packed ball. When that’s completed, they coat the meat with a saliva-like secretion to keep it from rotting.
With an adequate food supply available for their offspring, the beetle pair goes on to construct a brood chamber adjacent to where they buried the carcass. About two days later, the female lays as many as 30 eggs in the chamber.
One parent, usually the female, stays with the eggs until the larvae emerge around four days later. The larvae hurry over into a crevice their mother has excavated into the mouse ball, where she feeds them liquid food. That goes on until the youngsters are able to eat the mouse meat by themselves. With their mother protecting them from competitors (such as other hungry insects), the larvae spend five to eight days eating and developing very rapidly. Then it’s time for the larvae to burrow into the soil and pupate. Two weeks later they’re adults, ready to survive on their own. The offspring won’t, however, breed until the following year.
So how would you recognize the American burying beetle if you see one? The bright orange markings on its shiny black body give it away. This beetle measures 1-1/4 to 1-1/2 inches in length when it reaches adulthood, and that’s a good bit larger than more typical beetles.
Now for some bad news. The American burying beetle was placed on the endangered species list in 1989. At one time this species was found in the United States and Canada from the east coast across to the Rocky Mountains. Now there are only a few populations in several states, largely restricted to areas least disturbed by human influence.
Fortunately, a few facilities breed this species in captivity. In Rhode Island, the Roger Williams Zoo has established two free-roaming colonies of captive-bred beetles. Several other facilities also have made a few small releases into the wild.
But why worry about an insect most of us have never seen, and probably don’t care to? This paragraph from a World Wildlife Fund publication explains: “All that lives beneath Earth’s fragile canopy is, in some elemental fashion, related. Is born, moves, feeds, reproduces, dies. Tiger and turtle dove; each tiny flower and homely frog; the running child, father to the man and, in ways as yet unknown, brother to the salamander. If mankind continues to allow whole species to perish, when does their peril also become ours?”
We’ll go along with that. But perhaps as important in this particular case, it would be much less enjoyable taking a hike without the help of the cleanup crew.
For more insights about the natural world around us, visit the Christies’ Web site, www.OurWindowOnNature.com. Here you will find more stories and observations about the birds and butterflies, mountains and deserts, and many of the other outdoor wonders the couple has discovered during their travels.