St. Louis Zoo is working to save a beetle that needs the dead to survive

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

And this is not just a coverup.

“They take this body into this underground bunker that they made,” Bob Merz said. Once in there, they roll it into a ball and cover it with preservatives.

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

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

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

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

While trick-or-treaters prepare their Halloween costumes, Merz and his colleagues in St. Louis Zoo to stage a comeback for the creepy American burying beetle.

A macabre insect

In a closet-sized quarantine room in St. Louis Zoo, hidden away from the public, there are more than 100 burying beetles hiding in compressed paper towels inside transparent individual containers. The inch to inch and a half long black insects have bright orange spots on their backs.

This is the zoo Center for American Burying Beetle Conservation.

When the American Burrowing 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 sure all we had to do was look for it,” Merz recalled.

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

“Then we started to realize that a more intensive effort needed to take place,” Merz said.

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

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

To breed the insects, users place a potential beetle pair 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 a meatball shape. The female then lays eggs.

“Once those eggs hatch into the little caterpillars, (both mother and father beetles) are actually taking care of their babies,” said Kayla Garcia, the zoo’s head of invertebrates. “This is really, really rare in the insect world.”

The beetles make little peeping sounds to each other to communicate while the parents regurgitate food for their larvae, “just like (how) a mama bird feeds her babies,” Garcia added.

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

The surveyors attract burying beetles by putting rotting chicken parts out in mason jars, which Gann said is “stinky. It stinks a lot.”

“But it’s also exciting because when you see one of these guys in the trap, 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 drop without giving them all the food and providing things for them,” Merz said. “But we didn’t expect it to drop to zero.”

In the wild across the country, the beetles clearly struggle to find the right conditions for reproduction, but scientists are not quite sure why.

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

A Goldilocks beetle

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

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

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

There are several theories as to why the beetle’s numbers have declined, and researchers believe that a combination of ecological factors is putting pressure on the beetle. These include loss of habitat to agricultural land, declining populations of the animals whose bodies the beetle uses to feed its young and even light pollution, which can 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 its burial, but went 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.

“The goldilocks are the ones that are going to tell us when there are environmental stresses that are affecting them,” Merz said. “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 fastidious American burying beetle, Hoback said humans will also protect all the other living things that depend on the same habitat.

“They range widely and they need carcasses, so it’s really hard 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 a lot of other plants and animals.

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

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

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