Blue Ridge Naturalist: Beetles of Eastern North America

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The author discovered this ¾-inch glowworm (a type of beetle) late one night in her gravel driveway. (Photo credit: Marlene A. Condon)
The author discovered this ¾-inch glowworm (a type of beetle) late one night in her gravel driveway. (Photo credit: Marlene A. Condon)

By Marlene A. Condon

Twenty years ago, on a balmy late-August night, I noticed a mysterious bluish-green glow in the driveway. In amongst the gravel, roundish spots and lines of light could be seen, somewhat similar in color to that of a firefly, but glowing steadily instead of blinking. I ran inside for a flashlight to get a better view of whatever was producing the light, and I discovered a creature I’d never seen before.

It was about ¾ inches long and looked to me very much like a cream-colored caterpillar, with red spots enclosed by black squares along its top and darkish spots along its sides. When illuminated by the flashlight, you couldn’t tell this little creature was making light, but in the darkness it was quite visible—even from several feet away!

I was never really sure exactly what kind of animal this was. I had surmised that it was a glowworm—a type of beetle closely related to fireflies, but classified in a different family. The problem was that I hadn’t been able to find a picture in a book that matched my animal so that I could be certain of my identification.

Thanks to Arthur Evan’s new book, Beetles of Eastern North America, which contains more than one photo of the exact animal that I took a picture of two decades ago, I finally know that I did, indeed, see a glowworm in the Phengodidae family. I learned that the larva (the immature form) and the adult female look almost identical and that both feed upon millipedes.

The book includes a photo of a glowworm with its main prey “in hand,” and the author explains how the insect subdues the millipede:

“A glowworm larva overpowers its prey by coiling itself around the front of a millipede’s body. It bites the millipede just behind and underneath the head with sharp and channeled sickle-shaped mandibles that deliver gut fluids laced with paralyzing toxins and digestive enzymes. Immobilized almost instantly, the millipede is unable to release its noxious defensive chemicals and quickly dies as its internal organs and tissues are liquefied. The larva consumes all but the millipede’s exoskeleton and defensive glands.”

Art Evans, whom I know because of our shared interest in insects, is considered a noted beetle expert. Yet as knowledgeable as this scientist is, his writing is clear and accessible to everyone with an interest in learning about the largest grouping of animals—not just insects—in the world: beetles.

Containing color photographs of 1,409 species representing all 115 families of beetles in eastern North America, this is the ultimate “field guide” to these insects in our area. Weighing over four pounds, this isn’t a book you can carry into the field, but it is one you can enjoy looking through while seated in the comfort of your home.

What’s especially wonderful about it is that it doesn’t just help you to identify the beetles you are most likely to come across, it also provides the most interesting (to my mind) detail of an insect’s life—what it eats. With that bit of knowledge, you will know whether or not you are likely to ever see one of these invertebrates in your yard if you know what plants are on your property.

Or you might want to grow a particular kind of plant so you can try to attract some of these insects to your wildlife habitat. A great number of species are truly lovely to see.

One example is the Dogbane Beetle. Every year I make a point to look for it on my Indian Hemp (Apocynum cannabinum), a native wildflower that found its way into my garden many years ago. The Dogbane Beetle is absolutely gorgeous, with wing covers that shine in red, green, and gold, especially when seen in sunlight.

If you don’t know much about beetles, you can learn a great deal by reading Art’s introduction. He writes only briefly about topics that the casual observer may not have a particular interest in, such as the details of scientific classification. But he devotes about two dozen pages to such fascinating information as mating behavior, parental care of young, metamorphosis and development of the various life stages, adult feeding, defense tactics, when and where to find beetles, and how to photograph them.

Although it is typical of books about insects to also discuss collecting them—killing individuals in order to mount them on pins in a box—I find the continuation of this activity unfortunate as well as unnecessary. The justification for taking the lives of these animals is explained away by claiming that it is necessary to gain knowledge about them.

Yet the only information you can obtain from a dead insect are the details of its anatomy, which perhaps is interesting to some folks, but which is hardly very useful in the scheme of things. If you really want to understand (and to help) insects, you should watch them to learn actual details about their lives: what they eat, when they eat, what eats them, how they mate and where, etc. In other words, what roles they play in keeping the environment functioning properly.

Physicist Richard Feynman understood that the details of an animal’s life comprise true knowledge. Substitute “insect” where it says “bird” in the following quote from him and you can see why killing and pinning insects is not particularly enlightening:

“You can know the name of a bird in all the languages of the world, but when you’re finished, you’ll know absolutely nothing whatever about the bird… So let’s look at the bird and see what it’s doing—that’s what counts. I learned very early the difference between knowing the name of something and knowing something.”

Sadly, the value of such nature observations seems to have been lost in today’s world. Just about every type of biologist insists that knowledge can be obtained only by intruding upon the personal lives of animals; that is to say, by handling and marking (and thus terrifying) them, or—worse yet—physically harming or killing them.

In physics, we have the “observer effect,” which states that measurements of particular systems cannot be made without affecting those systems.  Biologists have come to realize that there is a somewhat similar observer effect when plants are touched, animals are probed, and cell cultures disturbed.

I would say that the observer effect is especially applicable to wildlife monitoring.  “Marlene’s Axiom” is stated as “Factual information about an organism’s behavior cannot be accurately determined if humans intrude upon the animal’s sphere of existence.”

This premise is so self-evident that anyone who studies wildlife should be able to accept it without controversy.  Thus it’s hard for me to understand why hands-off observation seems to be frowned upon by today’s wildlife researchers.

 

9 COMMENTS

  1. Thank you for the posting, with the review of Evans’s new book Beetles of Eastern North America. I agree, it’s a fine book; I bought a copy for myself, and another for my son.

    You are sadly misinformed, though, when you say that “the only information you can obtain from a dead insect are the details of its anatomy, which perhaps is interesting to some folks, but which is hardly very useful in the scheme of things.” As a biologist who has published research based on museum collections (both on insects and on fishes), I know your view is very far from correct. Here are just a few of the important functions of museum collections of “dead insects” (and other organisms).

    -Building up (often over centuries) an accurate picture of the spatial distribution of each species.
    -Discovering “new” (previously unknown) species, which not infrequently are first recognized in existing collections.
    -Providing material for taxonomic revisions of groups of species (using those anatomical “details” you disparage), leading to improved understanding of the organisms and their relationships.
    -Providing information on abundance, seasonality, distribution, sex ratios, sexual dimorphism, etc. necessary to propose plans and laws to protect threatened and endangered species.
    -Housing “voucher specimens” from studies of the animal’s behavior, genetics, ecology, etc.: General biologists commonly misidentify their research organisms, and museum specimens from their work are the only way the identification can ever be checked and, if needed, corrected. As you surely know, closely similar organisms may have radically different ecologies, life histories, etc.
    -Teaching students and, indeed, the general public. Many a naturalist or field biologist was drawn to her or his passion by museum exhibits of pinned insects and other preserved organisms.

    I could go on at length, but I hope you begin to see the critical importance — the “usefulness in the scheme of things” — of permanent and growing museum collections of well prepared specimens accompanied by accurate field data.

    Keep up the good work,
    Michael

  2. Oh, and you quote Feynman approvingly when he says “You can know the name of a bird in all the languages of the world, but when you’re finished, you’ll know absolutely nothing whatever about the bird….” Evidently a deceased physicist (even a brilliant one like Feynman) can be woefully wrong about the powerful knowledge made available when you simply know the correct name of a biological organism.

    Once you know the correct scientific name of a bird, insect, flower, you have the key to vast knowledge about it. You then also know, for example, the genus and family to which it belongs, the other members of which share many attributes with it. You can look up what has been discovered and published about it — thousands of research papers for some common creatures; nothing at all for many others — which can guide you in what to look for as a naturalist, if you like. Truly, the name is the key to all knowledge about that species.

  3. Dear Michael,

    Thank you so much for writing.

    Writers can only fit so much into a newspaper column, which means a lot is left unsaid. Please let me clarify my comments.

    Regarding Feynman:

    I’ve written before about how much you can learn once you identify an organism. That said, however, I personally know far too many people who stop with the identification–for example, people who only care about adding a bird, dragonfly, or butterfly to a list of some sort. I had those folks in mind when I quoted Feynman. My hope was for folks to see that a listing of animal names doesn’t really provide much insight to the lives of these organisms, which is what is so fascinating.

    Regarding pinning:

    I agree that collections from centuries past have provided information to today’s scientist, but most of the things you referenced–such as abundance, seasonality, distribution, sex ratios, sexual dimorphism, etc.
    –can be replaced nowadays by photographs and well written notes about behavior, physical characteristics, etc.

    It’s hardly necessary to have entomology students at every college across the U.S. or around the world killing insects for no reason other than that it’s tradition. After all, most of these people are not going to ever do anything useful with their collections.

    The reason I am so concerned about this activity is because there exist far fewer insects in the world today than 50 years ago. I know this for a fact because I can now drive across the country without hardly needing to ever clean my windshield. When I was young, windshields were in constant need of cleaning because there were so many insects that got hit.

    There’s been such a HUGE loss of insect populations that I am not at all surprised that so many species of insect-feeding animals are dying out. And I am extremely concerned about the future of mankind in this insect-depleted world.

    As for your final statement about teaching, I can’t tell you how many times I’ve heard this justification for terrifying, physically harming, or killing animals. I give slide presentations from which people learn a great deal and which makes them want to learn more (it’s why they buy my book).

    I’ll always believe it’s far more interesting to see a live animal–even if just in a photo or video–than one that is dead.

    Ever so sincerely,
    Marlene

  4. Dear Marlene,

    Thank you for your thoughtful responses to some of my comments. There is no question that much remains to be learned about living insects, and that studies of live insects are vital. This, however, does nothing whatever to negate my points about the necessity of pinned specimens.

    Using good photographs to identify the living animal works well for birds, mammals, reptiles, and amphibians. WIth insects, it also works well for perhaps a few hundred of the most common and distinctive species. It is frankly naive to think that most North American insect species can be reliably identified to species from a photo. There is simply no substitute for a pinned specimen, examined under a microscope, often with examination of the aedeagus (sclerotized male reproductive organ) pulled out of the body and compared with published photos or drawings for an ID to species. The majority of species of beetles are quite small, frequently plain black or dark brown, and occur in families with hundreds or thousands of superficially similar looking species. Some common beetles that you can find at your porch light cannot be identified to species at all if they are female, unless perhaps they are copulating with a male that you collect and identify from its aedeagal structure.

    I am surprised by your claim that there has been a HUGE loss of insect populations, unless you refer to those in the rain forests whose habitat is rapidly being destroyed, along with so much biodiversity. But if you mean in North America, trillions of insects thrive here. Although humans have made concerted efforts to eliminate or greatly reduce some pest species (think of gypsy moths, boll weevils, Asian longhorned beetles), I don’t think a single one has been extirpated. There has likely been a reduction in the diversity of insects in the shrinking tropical forests, yes; but I’d like to see scientific evidence that there are fewer total insects in the world now than 50 years ago.

    That is an interesting point about your subjective “windshield splatter” population assessment. In my 30 or so years of beetle collecting so far (creating a modest collection of some 13,000 well curated, properly prepared and labeled, scientifically valuable specimens that will go to a natural history museum before or after I die), I have likely killed fewer insects — and with much more purpose — than you or I kill by driving a car once across the country. That’s probably fewer insects than a single tree swallow eats in its lifetime.

    Equally sincerely,
    Michael

  5. The well-known and the large, i.e. the vast minority of life would be all that our students would learn to study. Yes, learning about organisms and what they do and how they live by observation is important, but as or more important is learning how to study life. Since most insects (a massive part of life) are less than 4 mm in length the only practical way to study them is by collecting and preparing them. Students absolutely need to do this. They also seem to truly enjoy it, developing both an appreciation for all diversity and an understanding that all of life isn’t like a bird.

  6. Marlene,

    Perhaps tellingly, your assessment of insect populations based on windshield analysis is as flawed as your understanding of what it takes to correctly identify the average insect species. The later is covered by Will and Oliver. As to the first, over the years, auto engineers have improved the pitch of the car windshield and the shape of the vehicle as a whole so that a sweeping sheet of air forms a protective barrier over the windshield. This improvement in aerodynamics is to help fuel efficiency, but also blows most smaller insects over the car instead of crashing into the window. Thus, you have fewer insects to wash off per mile not because there are less insects, but because you are driving a better car.

    Michael Ivie

  7. To all who wrote,

    Regarding insect populations:

    Believe it or not, you don’t need to be a certified scientist to do science–you only need to be a truck driver! My husband has been driving the same type of truck, with a perfectly vertical, flat front box surface that has no improved aerodynamic properties (absolutely none!), for the past 16 years. In just that short amount of time, he has noticed how much less often he needs to wash insects off the truck.

    I have personally been an astute observer of the natural world ever since I was old enough to hold onto memories. A problem with a lack of institutional memory is that younger people have no idea how much things have changed over time. Trillions of insects today doesn’t compare with what we had 50 and more years ago.

    I gave the windshield example because I thought it would make things clear. As it hasn’t, let me provide another example: If we left the light on outside the door when I was a child, it was absolutely crowded with insects attracted to it. Nowadays you are lucky to get just a few moths.

    Regarding pinning:

    I understand that knowledge can sometimes be gained from dead insects. However, I believe that collecting simply for the sake of owning a collection is rather disrespectful of life. I don’t believe animals should be killed for no good reason, and simply owning a collection to look at it is not a good reason, in my view. I don’t want to get into a philosophical discussion so, please, let’s not. We’ve all made our points.

    Sincerely,
    Marlene

  8. Hi everyone,
    This is a fascinating conversation. I feel that Marlene makes a good point about the importance of natural history observations, which I’m all for and (I’m sure) everyone else is is as well. Indeed, it’s difficult to observe the behavior of a pinned insect 🙂 However, Marlene’s opinion that making an insect collection is unnecessary is a bit limited. In contrast, I would argue that by making an insect collection actually helps insects and the environment in the long-run. Each year I teach Insect Biology at Virginia Tech (just down the road from Crozet, Va) and have 40 undergraduates in my lab make a collection of pinned insects. Each year, my students comment that they’ve never before really noticed insects but now they’re collecting, observing, photographing and making really spectacular collections of local insects. I feel (from student responses) that undergraduates in my Insect Biology class have a much deeper appreciation of biodiversity and insects, their ecological benefit, and need to preserve their native habitats. For me, killing things does not feel right and when the students express the same, I mention that then now is the time to really make sure that the pinned specimen is used to its fullest extent. For example, properly pin, label and curate it; take the time to accurately identify it; and recognize its importance for scientific education and research. Many of the specimens that my students submit as part of their collections (those which are not taken home and proudly displayed in their apartment/dorm) are used for subsequent classes and identification practice. Other specimens are even donated to the Virginia Tech Insect Collection, which contains insects collected from the state since 1888! The value of pinned specimens have nicely been described by Kip Will, Michael Ivie and Michael Oliver. I’ll just mention a few important uses of the state of Virginia’s insect collection, which might resonate with readers of the Crozet Gazette and Blue Ridge Naturalist: (1) Using specimens representing disease vectors in the collection and their geographical coordinates from their labels (did you know that many insects in VA are vectors of nasty human/livestock diseases?), researchers have inferred how these insects might spread in distribution and in proximity to humans/livestock based on various climate models; (2) Using specimens in our collection, we have already named three new species of millipedes from Virginia, and like Kip mentioned, we must properly prepare only preserved specimens to do this (by the way, we’re looking for life on other planets, I think we should know what new life is in our very own backyard in Virginia!); and (3) Virginia Tech keeps a substantial collection of insects, or a state insect reference collection, to establish a baseline for understanding invasive and unwanted species, how long they’ve been here, and how quickly they’re spreading. It was back in the late 1800s that William Alwood (one of the state’s first entomologists) first compared a diminutive bug with the state’s then-reference collection to realize that it was the infamous/destructive San Jose Scale. Discovered in Albemarle County, VA, this discovery and (importantly) comparison against known insects from the state provided crucial rapid identification of this exotic species and the ability for the growers to respond quickly to control this threatening species. To this day, the collection is used as a reference to compare surveyed specimens captured in the VA port system to determine if they’re a danger to our health, agriculture, livestock, and environment. Most of these insects are super tiny and need to be collected (photographs will not do) in order accurately identify them. Insect collections really are wonderful resources and I encourage folks in Crozet, Albemarle County, Virginia and elsewhere to learn more about their use and role in research and education.
    – Paul

  9. Dear Paul,

    Thank you so very much for your very informative comments. I am absolutely delighted to hear about your students’ responses to your classes and also your own coments to them about making sure the collections are put to good use.

    By the way, I got my degree from just down the road (Virginia Tech).

    Ever so gratefully,
    Marlene

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