St. Louis Zoo tries to save a beetle that needs killing to survive | KCUR

The couple moving the body has only the moon to light their way.

And this isn’t just a cover-up.

“They’re taking this body to the underground bunker they created,” Bob Merz said. Once there, they roll it into a ball and coat it with preservatives.

Then they cut off pieces of meat to feed to their children.

Fortunately, no one in this story is human. They are American burial beetles, and their actions are gnarled but important, said Merz, deputy director of the St. Louis Zoo’s WildCare Institute.

By moving the dead bodies of small birds and rodents underground, the beetles perform an essential cleanup for the animal world. But their numbers have plummeted.

These unusual insects were once found in 35 states, but the U.S. Fish and Wildlife Service now considers them federally endangered.

While trick-or-treaters prepare their Halloween costumes, Merz and his colleagues at the St. Louis Zoo are working on a comeback for the creepy American digging beetle.

A macabre insect

In a closet-sized quarantine room at the St. Louis Zoo, hidden from the public, are more than 100 burial beetles, hidden in crumpled paper towels in clear, individual containers. The inch-to-inch long black insects have bright orange spots on their backs.

This is from the zoo Center for the Conservation of American Burrowing Beetles.

When the American digging beetle was listed as endangered in 1989, the only known population was in Rhode Island. Eventually, surveyors found small groups in Arkansas, Kansas, Nebraska and Oklahoma. The zoo tried to do the same in Missouri.

“We were convinced that all we had to do was look for it,” Merz recalls.

After more than 10,000 trap nights across the state, surveyors still had not found a beetle. The last known sighting in Missouri was in the 1970s.

“That’s when we started to realize that a more intensive effort was needed,” Merz said.

Twenty years later, the zoo has bred more than 14,000 American burrowing beetles in captivity. Center staff are also reintroducing them to specially selected locations in southwestern Missouri and surveying their numbers in the wild.

Getting to this point required a lot of matchmaking on the part of the zookeeper, using computer software to match beetles that are genetically diverse.

To breed the insects, keepers place a potential beetle couple and a dead quail in an orange bucket with a net on top. If the beetles are romantically interested in each other, they begin to process the carcass, removing feathers and fur and using preservative secretions to shape the carcass into the shape of a meatball. The female then lays eggs.

“Once those eggs hatch into the tiny larvae, both mom and dad beetles care for their babies,” said Kayla Garcia, the invertebrate zoological manager. “This is really very rare in the insect world.”

The beetles make small peeping noises at each other to communicate while the parents regurgitate food for their larvae, “kind of like (how) a mother bird feeds their babies,” Garcia added.

During the summers, the zoo releases beetles, hoping they will like their new home. Then surveyors check the beetles to see how they are doing. Zookeeper Rebecca Gann spent a summer in southwestern Missouri with the zoo’s field conservation team looking for the beetles.

The surveyors attract buried beetles by putting rotting chicken parts in pickle jars, which Gann says “stinks.” Very smelly.”

“But it’s also exciting because when you see one of these guys trapped, you celebrate a little bit,” Gann said.

There have been ups and downs in the zoo’s efforts to conserve this insect. In the first place where they were introduced, the population did not do so well.

“We expected that number to go down without giving them all the food and supplies,” Merz said. “But we didn’t expect it to drop to zero.”

In the wild across the country, the beetles are clearly having trouble finding the right conditions for reproduction, but scientists aren’t sure why.

The beetles have fared better at a second site in Missouri, near the first. But the zoo keeps a captive population, just in case.

A Goldilocks beetle

The American digging beetle is a “very challenging” species to conserve, says Wyatt Hoback, professor of entomology at Oklahoma State University.

“I’ve been working on this beetle for 26 years and sometimes I feel like I’m a bad scientist because there’s still a lot we don’t know,” Hoback said.

Hoback’s research focuses on how the beetle responds to temperature changes, which could help scientists understand how climate change could affect them.

There are several theories about why beetle numbers have declined, and scientists think a combination of ecological factors is putting pressure on the beetle. These include the loss of farmland habitat, declining populations of animals whose carcasses the beetle uses to feed its young and even light pollution, which could affect the insect’s nocturnal habits.

The beetle also lived in roughly the same areas as the American Passenger Pigeon, which would have been the right size for burial but became extinct in the early 1900s, Hoback said.

According to Merz, the decline is a sign of larger problems in the environment. He describes them as Goldilocks beetles.

“It is the Goldilocks beetles that will tell us when there are environmental pressures that affect them,” says Merz. “So all is not right in the world, all is not right in our environment, if the beetle cannot thrive.”

By working to protect the finicky American digging beetle, Hoback said people will also protect all other living things that depend on the same habitat.

“They have a long range and they need carcasses, so it’s very difficult to manage specifically for them,” Hoback said.

Hoback said the good news is that they are an “umbrella species” because protecting them also indirectly protects many other plants and animals.

Merz said one of the best things people can do is plant native plants to support the birds and small rodents that American burrowing beetles need to raise their next generation.

“All this is not without hope,” Merz said.

This story was produced by St. Louis Public Radio. It is distributed by Harvest Public Media.