Even a beetle needs a break. And the American burying beetle needs a big one -- it needs help to come back from a sharp decline in its numbers and range. So the Saint Louis Zoo is lending a hand.
We're helping these important little decomposers on several fronts: breeding them here at our Zoo, releasing our captive-bred beetles back into the wild, searching for remaining populations in Missouri, and helping coordinate the efforts of numerous scientists and government agencies. This work stems from the establishment of the Zoo's Center for Conservation of the American Burying Beetle.
Things are definitely looking up for these little guys. Our captive breeding efforts -- in full swing since 2004 -- have already paid off, and we've raised more than 1,000 American burying beetles here at the Zoo. (While this might not sound like a big deal to you, it’s a huge step for the species, whose numbers have been declining sharply.) Plus, we've released 50 pairs of our beetles back into the wild, in an effort to begin repopulating the United States with these helpful insects.
Why We Need More Burying Beetles
The bright red and black American Burying Beetle is one of nature’s recyclers. It plays an important role in many natural ecosystems by helping return vital nutrients from decomposing animals back to the environment. The beetle was once widespread across most of the lower 48 states, including Missouri. But it hasn’t been found in Missouri for nearly 20 years. Isolated, wild populations now exist in only a few states. The United States Fish & Wildlife Service lists the beetle as an endangered species.
Scientists are not exactly sure why the beetles have disappeared. While there are still plenty of dead animals for the beetles to scavenge, there are fewer animals of the appropriate size, like wild turkeys, prairie chickens and the now-extinct passenger pigeon. The beetles' decline may also be due in part to habitat loss and fragmentation, and increased pesticide use might also be a factor.
We have been searching for remnant populations in Missouri, (and hoping to help discover the reasons for the population reduction). So far we haven't found any, though we plan to keep surveying likely spots in the hopes that the species still exists in our state. Meanwhile, our Insectarium staff has been working hard to breed captive American burying beetles here on our Zoo campus. Here’s how we help the little guys play the mating game:
Recipe for Beetle Love
The “ingredients” for beetle romance at the Zoo might sound a little odd -- a dead quail and a bucket. To begin the process, our keepers fill a bucket with dirt, place a dead quail on top, then put the male and female beetle in the bucket.
The beetle pair buries the quail, then embalms it using oral and anal secretions. (Embalming the dead animal ensures its “freshness” when the hatchlings are ready to eat.) After the two beetles mate, the female lays her eggs in the soil.
The eggs hatch into small white grubs that depend on their parents to feed them.The grubs beg for food by stimulating the parents’ mouthparts, and the parents regurgitate (throw up) food for them. A pair of beetles sometimes cares for as many as 30 babies at a time this way!
The beetle parents feed the babies for most of their larval life. When the grubs are large enough, they leave the brood chamber and dig down deeper in the soil to pupate (turn into adults).Only then is the parents’ job done. The male emerges from the soil first, followed by the female a few days later. The shiny new adult American burying beetles finally pop up above the soil between 45 and 60 days after their parents first buried their "brood" quail.
Now the job really begins for our keepers. They place each newly-emerged beetle in a plastic home. Twice a week, they feed it mealworms and wax worms, and give it clean paper towels and clean water. As you can imagine, it's a huge job to feed all of our beetles every week!
Then the keepers put the new beetles to work making more beetles. Each adult is given an individual I.D. number, and its parentage is recorded. This information is critical, so that when it comes time for the beetles to mate, they don't breed with another beetle closer than a second cousin. Our keepers use a complicated formula based on each beetle’s age and genetic factors to determine which insect gets to breed next.
This system ensures an all-important genetic variation within the burying beetle population. But what does this mean for our Zoo staff? It means they have up to 20 breeding buckets in use at one time! (How would you like to keep track of so many little beetles?)
Repopulating the Wild
Breeding these beetles is only one part of our goal. Another focus of the Zoo’s beetle conservation project is the release of some of our new beetles back to the wild. In June 2005, two Saint Louis Zoo keepers took 50 pairs of our American burying beetles to a protected reserve in southeastern Ohio. They joined forces with a number of other state and federal organizations, including representatives from Ohio State University, who brought along 180 of their captive-bred beetles to introduce to the reserve.
First the beetles were delicately tagged for identification. This involved the gluing of tiny round, green tags to the insects' elytra (fore-wings). The release procedure consisted of placing the beetle pairs in small underground "burial chambers," along with a food source -- in this case a dead quail (yum!). Then the workers covered the holes with soil and a protective wire screen, to dissuade scavenging mammals from disturbing the site. Each of the 140 burial chambers was then marked with a flag.
It's not known whether the released beetles will survive in their new home or not. But researchers will periodically monitor the release sites over the next several years to assess the success of this reintroduction effort.
Getting the Beetle Experts Together
A third focus of our beetle conservation work involves coordinating the efforts of the many organizations and agencies that are contributing to the American burying beetles' recovery. Towards that end, the Saint Louis Zoo hosted a conference on beetle research in late 2005. Leading specialists from various agencies, universities and other organizations gathered to share the results of their ongoing efforts. (A similar conference will take place at the Zoo in 2006.) One outcome of the conference was our establishment of a web site that will serve as a central location for all research data and other pertinent information on the recovery of the species.
A Hopeful Future
The Saint Louis Zoo is proud to be playing a part in helping restore the American burying beetle to the wild. Our collaboration with the many organizations working on behalf of this species may someday result in these important decomposers once again thriving throughout the United States.