Tuesday, January 24, 2012

American Burying Beetle

What a bug! Clad in the colors of Halloween and sporting a huge pair of intimidating mandibles, an American burying beetle, Nicrophorus americanus, poses for my camera. These giant beetles have a lifestyle that those prone to anthropomorphism might regard as ghoulish. But Nature seemingly evolves an animal to fill every role, and burying beetles play an important part as Mother Earth's undertakers. Just about anyone who clapped eyes on one of these goggle-eyed chaps would prclaim it a handsome insect, although they might revise their opinion once they learn of the beetles' habits.

While at the Wilds back in December - see previous post - I begged conservation science director Jenise Bauman to give me the nickel tour of their burying beetle restoration project. She obliged, and into that unassuming little building we went.

The Wilds does not confine their research and conservation efforts only to the charismatic mega-fauna featured in the previous post. American burying beetles are about as obscure and far from the average citizens' mind as it is possible to get in the animal world. To my mind, the Wilds deserves major kudos for working with an insect that is certainly not going to draw the accolades and attention that, say, their cheetah program does.

Why American burying beetles? Because they've become incredibly rare over their entire range, and at least until this project was initiated, had disappeared from the wild in Ohio. Historically, these inch-and-a-half bugs ranged throughout the eastern half of North America, living primarily in the imprint of our vast temperate deciduous forest. Today, small populations exist only in Rhode Island and a very limited area of Arkansas, Oklahoma, Kansas, Nebraska, and Texas.

Prior to European settlement, as many as five billion Passenger Pigeons dwelt in the primeval eastern forests. Wild Turkey abounded, and interwoven prairie regions contained an abundance of Greater Prairie-Chickens. These species all produced chicks that are/were of the perfect dimensions for burying beetle food. Mortality among the pigeon squabs, in particular, was probably high and dead chicks on the forest floor were probably a frequent occurrence. If the beetles' fortunes were tightly linked to that of the Passenger Pigeon, it may well be tough to successfully aid in a rebound of the beetle. A ray of hope lies with Wild Turkeys, which abetted by wildlife managers have increased dramatically. Perhaps doomed turkey poults will provide adequate sustenance to maintain American burying beetle populations.

Upon entering the beetle house, we saw these spartan beetle condos. Each container holds an adult.

This aquarium is full of another species of beetle: the mealworm beetle, Tenebrio molitor. The larvae of these darkling beetles are commonly used to feed all manner of grub-noshing pets such as lizards and birds. In this case, they provide a source of nourishment to overwintering burying beetles in the Wilds' beetle house.

An adult beetle would quickly make mincemeat of a mealworm with those powerful mandibles. They'll eat 'em in a pinch, but it isn't grubs that they thirst for - freshly dead birds and mammals is what floats the beetle boat. Those impressive whisk broom appendages that cap the antennae no doubt function as corpse radars, helping carrion-seeking beetles to home in on their meal.

An integral part of the Wilds' beetle operation involves breeding the beetles. In order to stimulate reproduction, a male and female are placed within a dirt-filled bucket, along with a quail carcass. The dead bird spurs the beetles to action. In this shot, one of the pair was busily tunneling under the quail's head - you can see its posterior protruding from the bird's lower left side.

Once the reproductive cycle is set in motion, things get interesting. American burying beetles possess Herculean strength, and it was amazing to see how the insects easily jostled the much larger corpse around. Eventually, the pair will at least partially bury their grisly fodder, and prepare it by stripping much of the feathers away from the carcass. The beetles then slather the body with bacteria and fungus retarding chemicals. By this point or soon after, Mrs. Beetle will deposit her eggs in a nearby brood chamber. Once the first instar grublets hatch, the doting parents gently transport them to the carrion. As the grubs are as yet unable to feed themselves, they stroke one of the parent's mandibles when hungry. Excellent providers that they are, the Mr. or Mrs. promptly regurgitates a snack of masticated dead meat.

The grubs grow through three instar stages, and then enter a month-long pupation after which they emerge as colorful adults ready to start this beetle magic all over again.

I hope the Wilds is successful in reestablishing American burying beetles in Ohio. Even though I'll probably never see one in the wild, I take great satisfaction in knowing that such creatures are on the landscape, and equal pleasure in the fact that people care enough to go to these lengths to try and ensure their survival.

Thanks to Jenise Bauman for touring me through the beetle house, and kudos to the Wilds and its affiliate the Columbus Zoo and Aquarium, and partners the Ohio Division of Wildlife, the U.S. Fish & Wildlife Service, and the Ohio State University for supporting this program.



Marvin said...

I'd love to see one of these large beetle, but probably never will. Thanks for your informative post.

OpposableChums said...

Fascinating. Thanks.

Anonymous said...

I live in Alaska, they aren't uncommon here at all, Ive seen them since I was a kid...overpopulation and habitat loss must be the main reason they aren't doing well in the lower forty eight....I just found one in the garden today.