Eew, Gross -- but Amazing
If you like your Halloween stories gross, you'll appreciate Burying Beetles. These sweeties help clean up our environment by burying small dead animals (birds etc) as food for their offspring. Indeed I found a hatch-out of Sexton Burying Beetles (Nicrophorus orbicollis) under a bush in my back yard, polishing off a mouse carcass.
N. orbicollis is common in Oklahoma but the larger American Burying Beetle (N. americanus, fondly called ABB) is critically endangered, so federal law requires that land where ABB might live must be surveyed before highways, construction, or pipelines can be built. This mandate sometimes causes resentment from land owners or developers! Meanwhile, scientists are discovering some surprising things about these beetles.
A TRUE STORY
Stephanie Rainwater, who seeks ABBs in her work with an Oklahoma civil engineering consulting firm, wrote:
“A company wants to build a pipeline between Tulsa and Cushing and they need to obtain a permit from the Corps of Engineers. To get that permit, they have to demonstrate that they are complying with the Endangered Species Act by either not impacting the beetles because they are proven to not be there, or by mitigating the impacts if they are there. We determine if they are there, then quantify the mitigation if they are.
"I had a long, interesting call with a hostile Creek County resident today. He now loves American Burying Beetles:
Me: Look, I get it. Can I tell you this beetle does some miraculous thing that absolutely no other species does? No, not exactly but let me tell you about what they do to their carrion.
Him: I’m listening.
Me: They de-feather/de-fur it then coat it with a mixture of oral & anal secretions that inhibits further decay as well as the growth of mold and bacteria. They preserve meat without refrigeration so it is available when their babies hatch. Now let’s talk about our soldiers.
Him: I love our troops.
Me: I know you do. Think about our troops in the desert. They have no refrigeration and they need protein. How is it currently preserved? Dehydration and/or unspeakable amounts of sodium. What do our soldiers need a lot of in the desert? Water. What does a high sodium diet make one need more of? Water. What can serve as a huge target in conflict areas? The huge tanks of water needed to keep our soldiers alive. If there is something we could learn from these beetles to minimize the quantity of water our soldiers need and improve their accessible diets, don’t you think we should do it?
Him: YES!!! Let’s make this beetle stuff. Who is making it? Let’s get it made.
Me: We don’t know how to make it yet but researchers are actively trying to figure it out. The thing is, if this beetle went extinct before the answers are found, what then? What if other species that have already gone extinct had answers for us that we never discovered?
Him: *long pause* I love this beetle. We need to save this beetle. I love our troops and I love this beetle and I’m really going to think twice before I stomp on any more of them.
Me: Good. You have a great night.
Him: You too. Thank you for telling me all of that.
With their tufted antennae, burying beetles can sniff a dead mouse from as far away as two miles. Together, a male and female pair carry the carcass to a suitable grave by moving under it. Then they dig the soil from under it, piling the loose soil on top until they have buried it safe from maggots and other scavengers. They remove the feathers or fur, coat the flesh with their antimicrobial secretions, and then mate. The female lays her eggs on top of the body. The parents even stay around to care for the larvae, feeding them on pre-chewed carrion. (How's that for “Eeww”?)
When the larvae pupate, the parents' job (and lifespan) is finished. About a month later, the new adult beetles emerge and overwinter, ready to clean up carrion the next spring.
Soil bacteria and fungi would rot a buried carcass before the beetle eggs could hatch, the larvae grow and pupate. But the parent beetles' secretions protect the carcass for their offspring, and some research is also finding anti-microbial activity in secretions of the larvae as well.
Researchers find that the beetle secretions contain high concentrations of lysozymes – enzymes that can break up the walls of gram-positive bacterial, destroying them. Work has barely begun on figuring out how to produce a lot of this, or whether we can use it to preserve our food too! But we need to protect this endangered species so that we can continue to learn from it.
Dr. Wyatt Hoback, Assistant Professor of Entomology & Plant Pathology at Oklahoma State University, is one of the scientists studying the secretions of the endangered American Burying Beetle.
In England: Antimicrobial secretions and social immunity in larval burying beetles, Nicrophorus vespilloides Animal BehaviourAugust 15, 2013 Andres N. Arce, Per T. Smiseth, Daniel E. Rozen.