One of the rarest insects in the United States — a beetle that hasn’t been seen in the wild in Missouri in 40 years — will be reintroduced to the southwest corner of the state this summer, officials with the Saint Louis Zoo announced Tuesday.

Plans are to release about 120 to 150 pairs of American burying beetles (Nicrophorus americanus), which were bred in captivity at the zoo, at Wah’Kon-Tah Prairie north of El Dorado Springs. The 4,000-acre site, which spans St. Clair and Cedar counties, is jointly owned and managed by the Missouri Department of Conservation and The Nature Conservancy. It also has been the focus of other restoration efforts, including the greater prairie chicken.

The beetle reintroduction will claim two firsts: It will be the first “nonessential experimental” population of insects to be reintroduced in the United States, and the first endangered insect species reintroduced in Missouri.

Often referred to by biologists as “nature’s recyclers,” burying beetles are aptly named: They bury carcasses of dead animals to provide food for their larvae.

Scott Hamilton, a biologist with the U.S. Fish and Wildlife Service, described the insect as “perhaps the cleanest competitor for carcasses out there.” The beetles compete for a food source with other scavengers, such as flies and rats, that not only eat carrion but can spread disease to humans.

Burying beetles mate for life and care for their young — one of the few species to do both. At 1 1/2 inches long, they are large for a beetle, but they are not often seen because they live mostly underground and are largely nocturnal.

According to the U.S. Fish and Wildlife Service, no American burying beetle has been found in Missouri since the mid-1970s, when the last known one was collected in Newton County.

Once found in 35 eastern and central states and in Canada, the beetle was placed on the federal endangered species list in 1989, according to Hamilton, who has been a leader in the reintroduction effort. At the time it was placed on the list, there was only one known non-captive population, in Rhode Island. Since then, remnant populations have been found in Arkansas, Kansas and four other states.



Rotting chickens

For years, Bob Merz, director of the Saint Louis Zoo’s Center for American Burying Beetle Conservation, drove around the state with rotting chickens and handmade traps in an effort to determine whether any of the beetles were left. He found none.

Since 2005, the staff at the zoo has had success in breeding the insect, with a captive population now totaling 7,000. Many of the insects are used to ascertain what is threatening the beetle, while others are slotted for reintroduction. Plans also are under way to attempt restoration in Ohio.

Reintroducing pairs of the beetles to the wild required a special designation from the U.S. Fish and Wildlife Service, which classified them as “nonessential” and “experimental.”

That means nearby private landowners needn’t worry that the presence of the protected species would restrict farming and other activities should the flying beetles migrate off the conservation area, Hamilton said.

Landowners can “keep on doing what they’re doing — livestock, burning prairies, development,” he said. “This is absolutely not going to affect their activities.”

The antennae of burying beetles are equipped with sensors that detect a dead animal from as far as two miles away, and the beetles are capable of flying several miles to get it. After finding a carcass, beetles often fight among themselves until the winning pair remains.

Once carrion is buried, beetles cover it with secretions that slow its decay and, in effect, embalm it. The female then lays eggs in the soil surrounding it, and when the larvae hatch in a few days, they have an instant food source.

After 45 to 60 days, a new generation emerges from the underground brood chamber. The process is repeated several times during the beetle’s roughly one-year life span.

The reintroduction will involve a similar, simulated process: Scientists will dig a hole, or plug, at selected sites, then place the carcass of a quail and a pair of beetles in each cavity and replace the plug. For the next five years, teams will monitor the sites for signs of breeding activity by checking for larvae and new adult beetles, and will survey nearby locations to monitor the movement of offspring.

The goal is to reach a stable population of 1,000 individuals or more, Hamilton said, which would ensure a steady population for the foreseeable future.

Hamilton said officials are unsure how far the reintroduced beetles will travel, making it hard to say whether populations will appear in other parts of Missouri if the reintroduction is a success. He’s also unsure what variables may pose a threat.

“It’s tough trying to figure out what we need to do for these species,” he said. “The most important thing is we need to try. Even in failure, we’re going to learn something.”