Essays

Wild On The Prairie: Invertebrates

Dung beetles are understudied, despite being very important to local ecology
July 2, 2000

On Brandon Young’s first day of work I set out to evaluate his knowledge of the local flora and fauna. Although Brandon is a college graduate, his degree is not in “nature interpretation”. Such a degree probably does not even exist. We took a hike along the trail exchanging folklore riffs.

“This plant is known as "hierba de hormiga", but I have not found a specific relationship between it and ants. Maybe the leaves can be rubbed on a harvester ant sting and the pain goes away – or maybe ants never have nests near it, and you could put the dried herb around your house so ants were repelled.”

“Doveweed is a good insecticide, though.”

“Yeah, and one leaf rubbed on meat gives it a sage-y flavor.”

“Isn’t it weird… a plant can be a flavoring and a poison, for croton oil comes from the genus of doveweed, and one drop of it is deadly poison.”

The conversation meandered in many directions: Mammal distribution, plant succession, cultural perceptions of tarantulas (as we tickled one out of its hole), ornithological population fluctuations, and on and on in the way of naturalist interpreters. As a profession, we are generalists -- knowing a little about a variety of things, and not necessarily experts in anything.

Brandon stopped short and pointed down.– “Look at that beetle.” I looked down but did not see anything, so he knelt and pointed. This time, I saw a rabbit dropping rolling along on the bare soil. I had to drop to my knees to see that a beetle one third the size of the dropping was rolling the tiny sphere of dung.

“Holy-moly, good grief – I have never ever seen this!” I walk the trails at the Sibley Nature Center and the Gone Native Arboretum almost every day, and have done so for 20 years. No matter how much time I spend outside, though, there will always be something new to see.

We watched the little beetle for a few minutes, and then continued our walk. Later, as I was putting the final touches on a recent writing project, we discussed the research methods and subject development techniques a nature writer might use. I immediately thought of the tiny dung beetle.

The Sibley Nature Center Library has several books on the identification of beetles of the United States. Dung beetles are listed as a member of the Scarab Beetle family. Ancient Egyptians noticed Dung Beetles rolling balls of dung, and then burying them. A few weeks later beetles emerged from the burial site. Scarab Beetles became a holy symbol of reincarnation to the ancient Egyptians. The ball of dung was likened to the sun, and the beetle to the power that propelled the sun across the sky. The scarab represented the sun god, their most important deity.

Unfortunately, seven thousand plus species of dung beetles have been identified world-wide, making our efforts to identify the beetle extremely difficult. No book lists every species that could possibly be found on the southern Llano Estacado. Several genera of dung beetles are mentioned in the books, and flipping through, we decided that one genus might – just maybe – be that of our little beetle.

The Sibley Center maintains a file of thousands of magazine and scientific journal articles. We pulled out the Beetle folder and found two magazine articles on Dung Beetles, but no research papers on the Dung Beetles of the Southwestern United States. Nowadays, anyone with a computer and a phone has access to the World Wide Web. Our old 133 megahertz machine sputtered to life, and several minutes later Google spit forth some additional possibilities.

AnswerSleuth yielded four pages of website summaries. Sorting through the dozen or so that were listed, we ran across the same genus referenced in the Sibley Library book. A European species of that genus specializes in rabbit dung.

“So was that a European species of beetle we found, and if so, how did it get here?” Although Australia has 250 native species of dung beetles to process hard, dry kangaroo poop, settlers there had to import dung beetles that can process the dung of large herbivores to keep from being buried alive in cattle dung. Even without deliberate importation, many arthropods travel with humans, unseen and unnoticed, as we move about the globe. For example, two species of garden snail that reside in everyone's backyard come originally from Europe.

“It could be the same species. Some insects are cosmopolitan. For example, the Orange Dragonfly, Orthemis ferruginea, so common here, is found worldwide. It is more likely, however, that different arid regions of the world have their own species of rabbit dung specialists.”

“Humans like to give everything a name, so should we call this beetle by that genus name?”

“Aphodius. That is easy enough to say. I wonder if we will ever find out what it means. I wonder if Aphodius was a member of the Greek or Roman pantheon?” (Deborah Williams later postulated that Aphodius would mean "dislikes light", after examining word derivations in the dictionary.)

“There are 1000 species of Aphodius world-wide -- so we might even be correct!”

“OOOOH! It says here that there is a species of dung beetle that specializes in human droppings! Americans think everybody has a bathroom with a toilet, but…”

“I wonder if our little rabbit poop species flies. Most large herbivore-dung species have to, because their "hosts" are spread across the landscape. But we can find at least one rabbit pellet per square yard, so these may be able to walk to the dinner table.”

“Hmmm… here is a reference that associates dung beetle activity with rain. That makes sense – they could not bury the dung in hard dry soil. So, areas with rainy seasons might have more diverse dung beetle populations, right?”

“There are three main types of dung beetles -- Tunneler dung beetles dig a burrow below the dung. Rollers roll a ball of dung away. Some species are Dwellers, and just live inside the dung. Many species defend their young… because earthworms will eat the dung balls and the eggs within!”

“Some beetles survive several dry years, waiting deep underground for rain to awaken and rejuvenate them. Some survive as adults, and others survive as eggs in buried dung balls.”

“Oh, dear – Aphodiinae is a sub-family, a super genus, as it were. Academic specialists have divided it! What are we going to call our beetle? Our common name will be "Rabbit-poop Beetle", but it looks like we cannot find a proper scientific name to call it…”

“Hmmm, here is a tiny flightless dung beetle that lives in loose dunes. It is an endangered species in California.”

If we chose to continue the search to find out more about our dung beetle, we would have to write to the authors of the scientific articles we found. A Dung Beetle Association, if one existed, might be just the ticket. For now, though we will have to be content with adding our local observations to the meager body of scientific work we found.