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.