We've been hearing a lot about the proposed Keystone Pipeline in the news recently. The controversial pipeline would cross the midsection of our country, carrying oil from Canada to the Gulf of Mexico. Many arguments for and against the pipeline are being batted around, most concerning environmental matters.
With a lot of big issues being discussed, I thought it was interesting that there is a very small one - nicrophorus americanus, the endangered American burying beetle. An environmental impact statement discusses steps that should be taken to minimize harm to beetles, including controls on lighting, height of vegetation and more.
Burying beetles are often called sexton beetles, named for the sexton, a church caretaker who was also the gravedigger. There are several species of nicrophorus beetles in the U.S., but to my knowledge, only N. americanus is endangered.
Burying beetles are large, elongated beetles, ranging from around -inch to 1 inches long. Some are solid black, others have large red blotches on their wing covers. N. americanus is the largest and the only one with an additional red blotch on the pronotum-the section behind the head.
As their name tells us, these beetles bury bodies - in this case, the bodies of small dead mammals or birds (not humans or large animals). They have a keen sense of smell and are said to be able to smell a dead mouse from two miles away, within an hour of its death. They are nocturnal.
Burying beetles work in male-female pairs and are among the few insects where both parents care for the young. When they find a dead animal, they crawl under it, roll onto their backs and move it by passing it along with their feet. They do this until they find soft enough ground to bury it. They remove soil under the body so that the body falls into the hole, then they pile soil over it.
The beetles remove fur or feathers and shape the body into a ball, then "treat" it with secretions that prevent it from decomposing too quickly. The female digs an adjoining egg chamber and lays eggs. When the larvae hatch, both parents feed them with regurgitated food. They also keep the ball of food clean and free of fungi.
The larvae finish the food in about a week, leaving the bones, and are ready to pupate. Their work done, the adults fly away and will die when cold weather arrives. The larvae pupate in the soil for about a month, emerging as adults in mid-summer. They will not reproduce that year, but will hibernate during winter.
New adults awaken in spring and reproduce in early summer. Adults live about a year. They are scavengers and eat decaying plant and animal material and occasional live insects.
Burying beetles theoretically should be very successful creatures. They work at night, when the flies that compete for dead bodies are asleep. They bury their food, getting it out of range of competitors, and they care for their larvae, giving them a good start in life.
Nicrophorus americanus was once found in 35 states from Maine to Florida and three Canadian provinces. Now it is found only in Oklahoma, Arkansas, Nebraska, Kansas, South Dakota and Rhode Island, and researchers have not yet figured out what happened. The beetles do not seem to be associated with any particular type of soil or vegetation.
Habitat destruction is considered as the likeliest cause. Human activities infringe and break up areas of good habitat, making changes in the types of small animals and birds that can live there. Broken habitats add to what is called "edge effects" that favor foxes, raccoons, crows, skunks and other creatures that compete for dead animals.
Attempts are being made to re-introduce the American burying beetle from laboratory colonies being bred in Massachusetts. Whatever your opinion on the pipeline, the American burying beetle is still a very interesting creature.
- Send your insect questions to Claire Stuart by e-mail at firstname.lastname@example.org or write her (with self-addressed stamped envelope) in care of Living Section, The Journal, 207 W. King Street, Martinsburg, WV 25401.