Backyard beetles, good or bad?
by Arthur V. Evans
Princeton University Press, 2014
560 pages 8" x 10"
GARDENS AND BARNYARDS attract a wide variety of beetles, some beautiful, others downright ugly. It's tempting to kill the scary looking ones and let the pretty ones live another day. But then you have the look-alikes--beetles that are similar in appearance but entirely different in habits. So before you decide whether or not to welcome a particular beetle to your yard, you need to be able to identify it.
While some of the more common beetles are easy to identify, others can be decidedly problematic. That's because of the vast number of beetles roaming North America.
According to the book Beetles of Eastern North America by Arthur V. Evans, beetles are the world's largest and most diverse group of animals. Beetles make up one-fifth of all plant and animal species in eastern North American, counting among them 115 families and 1,409 known species. Evans' 560-page book, which is packed with color photos of beetles, describes a mere 10 percent of the species living in the eastern regions of North America.
Still, this book makes a terrific starting place for identifying beetles. Just flipping through the pages looking at all the colorful insects makes you want to rush outdoors to see how many of them you might spot in your yard.
One of my favorite activities is wandering around the garden with my camera, snapping photos of beetles so I can examine the close-ups to try to identify them. As an alternative to shooting photos, Evans suggests collecting specimens and using a magnifying glass to get a close look. Then compare what you see to the species identification guide in his book.
Until I acquired this book I had been attempting to ID beetles by their basic shapes and color patterns. But, says Evans, "Although colors and patterns are sometimes useful, beetles are classified and more reliably identified on the basis of their anatomical features."
Body shape, then, is a more important first clue than color pattern. Accordingly, Evans includes illustrations of 14 typical beetle shapes from elongated to oval to triangular to ant like. The nature of the beetle's surface is another clue. It might be shiny, dull or wax coated and may be either punctured with small pits or covered with bumps, ridges, whorls or wrinkles.
The head and its appendages are particularly fascinating when you see them up close and personal. The mouth parts vary according to whether they are designed for cutting and tearing flesh, chewing leaves, or straining fluids.
The antennae, which are the beetle's primary organs of smell and touch, come in 11 basic styles that might resemble thread, a string of beads, a saw, a comb, a fan, a feather, a club or a bent elbow.
Each individual beetle lives only weeks or months, and you are just as likely to see larvae as mature beetles. "The larvae of most beetles bear no resemblance whatsoever to the adults," Evans points out, "and function as though they were entirely different species in terms of food and habit preferences." Among larvae, five basic body types aid in identification.
If you get so enamored with beetles that you'd like to raise some of your own, Evans offers tips on setting up a beetle aquarium and on rearing larvae gathered from various sources such as in water, under bark or in decaying wood.
So what makes a beetle good or bad? Basically, what it eats. "Equipped with powerful mandibles, beetles are capable of cutting, grinding, or boring their way through all kinds of plant and animal materials, living or dead," says Evans.
"Most beetles are herbivores and obtain their nutrition by consuming living plant tissues. Scarabs (Scarabaeidae), blister beetles (Meloidae), leaf beetles (Chrysomelidae), and weevils (Curculionidae) are among the species that are particularly fond of leafy foliage and will strip leaves of their tissues or completely defoliate plants. Pestiferous beetles in these families hungrily consume turf, garden vegetables, ornamental shrubs and shade trees as well as agricultural or horticultural crops, while their subterranean larvae frequently attack roots."
Then you have the beetles that rely on fungi for their nutrition and are basically fungus farmers. "Bark beetles (Curculionidae)," for example, "infect trees with fungal spores that kill twigs and branches or eventually the entire tree."
On the other hand, many wood boring beetles feed on already dead or decaying wood, helping break it down into forest mulch. "Their tunneling and feeding activities in twigs, limbs, trunks and roots hasten decay and attract a succession of additional beetles and other insects that prefer increasingly rotten wood."
Hunter beetles prey on other types of insects, many of which are the bane of gardeners. "Rove (Staphylinidae) and clown beetles (Histeridae) hunt for maggots, mites, and other small arthropods living among leaf litter, dung, carrion, under bark, in decaying plant and fungus tissue, and sap flows...Lady beetles (Coccinellidae) consume a variety of foodstuff, especially pollen and molds, but are also predators of aphids, mealybugs and other plant pests."
Dung beetles specialize in burying animal feces, thereby helping fertilize the soil while cleaning up the ground surface. "Dung-feeding beetles (some Hydrophilidae, Geotrupidae, Scarabaidae) consume plant materials already partially broken down by the digestive tracts of horses, cattle, dogs and other vertebrates. These beetles consume and bury feces as food for their young and are among the most beneficial, yet least appreciated insects."
On the whole, beetles "are among the most beneficial animals, but it shouldn't be a surprise that species that have evolved to scavenge animal nests, carrion, dead insects, seeds and decaying plant materials in nature are also adapted to exploit these very same materials improperly stored in our pantries, warehouses and museum collections. Beetles in several families infest and damage stores of grains and other cereal products, dried meats and fruits, legumes, nuts, and spices."
To help you identify all these various bad and good beetles, the vast majority of Evans' book--some 440 pages--consists of fabulous photographs of 1,500-plus beetles, accompanied by a brief description of each. They are organized by family and each section includes a list of similar-looking families. Collecting notes give you a hint where to look for each type of beetle.
Although each written description indicates the beetle's size, all the photos are scaled alike, unfortunately making all the beetles appear to be the same size. As a visual cue, I would like to have seen a scale bar included with each photo.
Also, unless you are thoroughly familiar with the vast amount of terminology involved in beetle anatomy, understanding the descriptions can be a
bit intimidating. The glossary is not much help, as it defines most words in terms of other specialized terminology. And the index does not include the beetles' common names.
Although this book was clearly written for the coleopterist (scientist who studies beetles), it has much to offer anyone who wants to identify and learn more about the diversity of beetles commonly encountered in gardens, backyards, barnyards, and woodlots. I guarantee that if you do nothing but take in the colorful photographs in this book, you will never look at beetles the same again.
Gail Damerow enjoys trying to identify the many beetles that inhabit her farm in Tennessee's Upper Cumberland.
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|Publication:||Countryside & Small Stock Journal|
|Date:||Jan 1, 2016|
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