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Beetle Mania–Conserving an Endangered Insect at the St. Louis Zoo

The most interesting animal species on the planet often have an alias.  The blue-faced booby (A.K.A. masked booby); the pygmy chimp (A.K.A. bonobo); the black-footed penguin (A.K.A. jackass penguin); and the snot otter (A.K.A. hellbender) are just a few to mention.

American burying beetle (Nicrophorus americanus) at the St. Louis Zoo's Monsanto Insectarium. (Nat Geo Archives)

Not long ago, I wrote about the St. Louis Zoo’s Ron Goellner Center for Hellbender Conservation and the Zoo’s effort to reverse the “snot otter” or Ozark hellbender population decline.

The St. Louis Zoo, one of the premier zoological facilities in North America, has focused many of its conservation efforts on projects abroad that influence charismatic megafauna. They also conduct research on and conserve local, endemic species like the Ozark hellbender.

More recently, they have teamed up with other agencies and organizations to restore a beetle, and a very interesting one at that.

The Saint Louis Zoo’s Center for American Burying Beetle Conservation; the U.S. Fish & Wildlife Service; the Missouri Department of Conservation; and The Nature Conservancy are partnering to reintroduce up to 600 captive-born American burying beetles into the wild.

In June, and for the first time ever in Missouri, these conservation entities will release the Zoo-bred beetles in locations across the 4,040-acre Wah’ Kon-Tah Prairie in Southwest Missouri.

Important to forensic entomologists, the American burying beetle (Nicrophorus americanus), also known as the giant carrion beetle, is a critically endangered beetle, and perhaps one of the most ecologically important insects around. And it’s, of course, interesting enough to have an alias.

The American burying beetle was the first insect species in the US ever to be designated as endangered.  It is one of a few species of beetles which exhibits parental care. And last, but not least, its foraging ecology is most peculiar.

As a carrion beetle, the American burying beetle buries carcasses and ultimately tunnels through them. They also expectorate an antibacterial secretion that slows decomposition of the body. Living as long as a year, the American burying beetle, as mentioned, is a diligent parent. The female beetle lays her eggs near the preserved carcass. Within four days, the eggs hatch into larvae.  Both parents feed their offspring by eating some of the dead flesh and regurgitating it into the larvae’s mouths. This goes on for about six to 12 days, until the larvae begin their next stage of development, pupation. After 45 to 60 days, the new generation of beetles emerges from the carcass cavity.  This process is repeated during the beetles’ life span.

American burying beetle (Nicrophorus americanus) at the St. Louis Zoo's Monsanto Insectarium. (Nat Geo Archives)

“In recycling decomposing components back into the environment, this beetle is a necessary part of our ecosystem,” says Ed Spevak, Saint Louis Zoo Curator of Invertebrates.

The Zoo has bred nearly 7,000 American burying beetles since 2005.  The beetles, which were recently designated by the USF&WS as a ‘nonessential experimental’ population can now be reintroduced into the wild because the designation permits greater flexibility under the Endangered Species Act (ESA) for restoration activities in human populated areas.

“This designation took some time because we had to weigh the costs and benefits of reintroducing this species as a non-essential experimental population.  Getting this designation as a ‘nonessential experimental’ population does not mean that this is not an important species to conserve, but it does mean that we can offer some flexibility so that reintroduction does not interfere with the activities of nearby landowners,” said Scott Hamilton, U.S. Fish and Wildlife Biologist based in Columbia, Missouri.

Occurring in less than 10% of their historic range, the beetles once were found in 35 states. Pesticides, habitat loss and destruction, and even light pollution may have contributed to the species demise.  “Competition for carrion by scavengers is also thought to be an important factor in their decline,” Hamilton added.

“The beetle was last seen in Missouri in the mid-1970s, and for the last decade, the Zoo has been monitoring for existing American burying beetles—with none found,” said Saint Louis Zoo Zoological Manager for Invertebrates Bob Merz.  Merz is also director of the American burying beetle center that is part of the Zoo’s 12-center WildCare Institute dedicated to saving animals across the globe and at home.

Surveying for the endangered beetles has been the focus of the Zoo’s American burying beetle conservation efforts for the past several years. “Our contribution to reintroduction efforts by returning the beetle to parts of its former range is the beginning of the recovery of this beautiful beetle,” says Merz.

Although some aspects of this beetle’s lifestyle may lead you to think of it as a rather grotesque insect, it may compensate for its rather revolting foraging and reproductive behavior through its benefit to ecosystem health as a indicator species. It also happens to be quite a beautiful insect.