BEETLES. Yes, we are going to talk about beetles—but not how to get rid of Japanese beetles, or Asian lily leaf beetles, or cucumber beetles. Instead let’s celebrate the largest group of animals on the planet and the roles they play with the man who knows at least as much as anyone anywhere about them, Dr. Art Evans, author of the astonishing new book from Princeton University Press: “Beetles of Eastern North America,” the book that has held me captive since it arrived on my desktop this summer. (You can win a copy, too.)
Working primarily as an independent researcher, Art Evans is a research associate at the Smithsonian Institution, Virginia Natural History Museum, and Virginia Commonwealth University (VCU). He is also an adjunct professor at VCU, University of Richmond, and Randolph-Macon College, and creates a weekly radio spot called “What’s Bugging You” on Richmond Public Radio, along with a popular Facebook page about–you guessed it–insects!
Though a massive guide to beetles like “Beetles of Eastern North America” might sound like it’s not for you, it is.
“Even though I hope my colleagues will enjoy and appreciate the book,” says Art Evans, “they were not my primary audience. My primary audience were people like yourself, who may appreciate nature but may not have taken the time to look and see what beetles are living amongst them.”
On his recent return from a trip working on the next volume—a Western edition—Art Evans was the guest on my August 25, 2014 public-radio show, transcribed below.
my beetle q&a with art evans
A. And that’s just the tip of the iceberg–approximately 10 percent of the beetle fauna that probably exists east of the Mississippi River.
Q. That’s only 10 percent?
A. Yes, and that’s an estimate. There are about 25,000 species of beetles in the United States, and there are about 400,000 species worldwide. So my goal was to at least have one representative of all of the 115 families of beetles known to currently occur east of the Mississippi River, and then to include as many different genera as possible.
Q. So if you’re a beetle expert—that would be a Coleopterist, yes?
A. Right, because all beetles are in the order Coleoptera.
Q. So what makes an insect a beetle?
A. Beetles are distinguished from other insects by a number of features, but primarily their modified forewings, that are either hard and leathery or soft and shell-like, and they’re called elytra. That is a physical feature that is unique to beetles, but they also like many other insects develop by complete metamorphosis—they have an egg, larva, pupa and adult. Those larvae can be known as grubs sometimes.
They also have chewing mouthparts that are variously modified to cut flesh or grind plant material, which your listeners may have noticed. [Photo below: The Eastern Hercules beetle, Dynastes tityus]
A. I also teach a course on insects and humans for non-science majors, and we look at how insects have influenced popular culture. You can look at many science-fiction monsters and machinery and clearly see how they were inspired by insects, including beetles.
Q. So beetles have these special forewings called elytra, these chewing mouthparts, undergo complete metamorphosis of egg, larva, pupa, adult—and there are vast numbers of them. Where does that put them among animals?
A. Beetles are the largest group of animals on the planet. Again: Close to 400,000 species.
Q. And they’re the top dog among insects….
A. …and since insects are the top dogs, if you will, among animals, that puts them on top of all the animals.
Q. The top of the top! Even a quick glance at he book reveals that beetles don’t all look alike. I’m embarrassed I didn’t know that fireflies are beetles, for instance. In the garden, I’ve seen crazy-looking ones–like the clavate tortoise beetle [photo below], which sort of looks like a teddy-bear shaped body under a clear shell.
A. They have this great protective shell that is what we call explanated—it has a flange all around the perimeter that extends beyond the body itself.
Q. Hence the “tortoise beetle” common name. So there’s that distinctive-looking beetle, and then there is the incredibly brilliant colored but much-loathed lily leaf beetle, with their tactic for protecting themselves against predation by pooping all over themselves. There’s probably a technical, scientific term for that. [Laughter.}
A. No, I think you’re saying it just fine. [Laughter.] Other beetles do that, too.
Q. And some beetles are iridescent, including another one we don’t love—the Japanese beetle. What’s that about? [Metallic-looking six spotted tiger beetle, photo below.]
A. Iridescence is thought to make them difficult to see. In many of these iridescent beetles, it’s often the result of different layers in the cuticle—the actual exoskeleton—that reflect different wavelengths of light, and gives them this iridescence. They’re finding that the iridescence may make them look less beetle-like, less conspicuous, like a shiny drop of resin or water. But they are also finding that other animals lack the visual acuity to see them as we do, and it could very well make them less conspicuous among the vegetation.
A. They fill a number of roles ecologically. They’re the largest group of animals found in terrestrial and freshwater habitats, and a few beetles even live right up to the ocean edge—you’ll find them under seaweed, or in freshwater pools, for instance.
They are primarily phytophagous, or plant-feeding, species—and they provide a natural pruning service, if you will. In a natural system they provide a natural control of plant communities.
Then there is a smaller subset, although significant, that are primarily predators, and they feed on beetles and other insects and small arthropods, and they can exert a little bit of pressure on animal community structure.
Q. So who eats beetles?
A. Any insectivorous animal out there: birds, reptiles, amphibians, fish, and some mammals will certainly eat them. Human beings in some parts of the world consider beetles or their soft-bodied grubs a delicacy. So it’s probably easier to answer: Who doesn’t eat beetles?
Q. And their defense mechanisms against predation?
A. In addition to some species being cryptic (or difficult to see), and being fleet of foot (and running away from a potential predator), some are filled with noxious or toxic chemicals. Others are very large, with hard exoskeletons, and they have sharp spines or horns that make them an ungainly mouthful at best. So it depends on the species.
A. That really caught my eye, because not everyone comes up with a burying beetle as one of their favorite beetles. I want to know more.
Q. Well everyone should tune out now or stop reading, because it’s a gross story. I had a cat, who came to me as a stray from the woods—a survivor kind of guy, who loved to eat rodents and such. He’d drag his kill up by the house, to a gravelly, loose area of soil, and have his supper, and leave part of it behind.
I would see the remains sort of dancing—like half a chipmunk, moving around–and then it would disappear underground eventually. And I thought: What in the world? Was it a snake underground or what? And then finally I gave in to the impulse and started looking, and it was burying beetles at work.
Nowadays, if I catch a mouse or vole in a trap, I put it in that spot, even though Jack is gone, and I “feed” the burying beetles. They are so amazing—what they can accomplish.
I have Nicrophorus orbicollis, a burying beetle [above photo], and Necrophila americana, the American carrion beetle, I believe [photo below].
And the burying beetles are just over a dozen species that are very similar in appearance—red and black, with truncated or blocked-off elytra that just barely covers the tip of the abdomen. They work in pairs, males and females. They’ll find the freshly dead body usually of a small animal, and they’ll begin to bury it.
They do that to beat the competition, because there are scavengers out there that will gobble up or drag off the remains, so these beetles need to secure them for their young.
So they bury the body and carefully shave it—they chew off all the hair or feathers, and then they knead the body and manipulate the legs or wings or tail or whatever’s there, and eventually it becomes this pear-shaped lump with a depression on top.
As they’re kneading it they’re licking it, and they have a fungicide in their saliva that retards the decomposition process.
Q. That’s amazing.
A. They do all this effort to prepare it for their young, and these burying beetles demonstrate the highest level of parental care in all of beetles.
Once they’re prepared the body in this chamber, the females lay their eggs. The young hatch and the adults will nibble on the remains and regurgitate it into this cup-like dimple on top of the remains, and they make a chirping sound—like ringing a dinner bell—and the larvae will charge up to the top of the thing and feed on this squirrel puree or whatever it is.
Q. And again: I apologize to everyone listening (or reading) who thinks it’s so gross—but I think it’s so important, and it’s what I love about gardening:
It brings me into contact with the connection between living things.
This is a very complex picture that these burying beetles are examples of: where nothing is wasted, everything has a purpose, and it’s a big chain of co-evolved behaviors.
A. I always refer to beetles and other insects as part of the FBI—and the FBI are fungus, bacteria and insects, the agents of decomposition. They help break down dead plants and animals and animal waste into its most basic components—nutrients–and therefore making them available to other organisms.
Q. So are these detritivores, or…?
A. They’re saprophages.
Q. Any other extreme ones that you want me to be sure to read up on in the new book now that you know about my burying beetle thing…
A. …your proclivities? [Laughter.]
One type people are always interested in are the fireflies, or lightning bugs—these bioluminescent beetles that are a familiar sight. The fact is that all their stages are bioluminescent–the egg, larva, pupa and adult. [Adult of big dipper firefly, above photo.]
That bioluminescence serves primarily as a feeding deterrent; it’s an aposematic warning that lets potential predators know that they have noxious chemicals in their tissues—leave them alone.
In adults their bioluminescence serves another function, and that’s in locating mates and mate recognition.
Q. Fantastic, and thank you.
enter to win the book
I’VE BOUGHT TWO EXTRA COPIES of “Beetles of Eastern North America” to share with lucky readers. To enter, all you have to do is answer this question in the comment form at the bottom of the page, after the very last comment:
What most surprised you from this interview about beetles? Is there a beetle you know best (preferably one that you don’t loathe, but whether love or hate, let us know)?
What surprised me was the vast number of species in the world; my favorites, as you now know, are the burying types. No answer? You can just say, “Count me in,” but a reply would be even better. Thanks.
I’ll select winners at random after entries close at midnight on Monday, September 1. Good luck to all. US and Canada only.
more from dr. art evans
- Listen to his weekly “What’s Bugging You” radio show
- Visit his Facebook page (where you can also ask for insect IDs by sharing a photo)
get the podcast of my radio show
MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its seventh year in March 2016. In 2016, the show won three silver medals for excellence from the Garden Writers Association. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).
(Photos except clavate tortoise beetle and six-spotted tiger beetle courtesy of Dr. Art Evans; used with permission. Disclosure: Amazon affiliate links yield a small commission.)