Bugs in Vegas, Part 2
Friday, August 14, 2009
In part one I gave some background information and looked at an insect book that covers the Southwest, fine for reading at home. But if you’re out on a hike, even if it’s just out to the front yard, and want to identify insects, take along a field guide. In this article I’ll look at three insect field guides covering North American insects.
First, the classic “Insects” by Borror and White. This is one of the deservedly famous Peterson Field Guides. The complete title is “A Field Guide to Insects: America north of Mexico.” It is definitely old school. At the front and back of the book is a pictorial binary key to identification. It’s like the game “Twenty Questions.” A binary key asks a question with a yes-or-no answer which either points you to the proper page or to the next question. For example, the first question is, basically, does it have wings or not? If not, you are directed to another chart in the back of the book. But if it has wings, the next question is, are the wings “covered with minute scales; mouth parts a coiled tube” or “wings not covered with scales, usually clear; mouth parts not a coiled tube.” If the answer is yes (wings with scales and mouth parts a coiled tube), the book refers you to page 218 where the discussion of Lepidoptera (butterflies and moths) starts. If the answer is no, there are more questions to be answered until one arrives at the correct page.
If you have never encountered a binary key before it can be daunting. Also, you may have to know something about insect anatomy to use it. For example, to answer the question whether or not “cerci are present” you have to know what cerci are. Yet, if one make the effort and learns how to use it, a binary key can quickly lead you to the correct identification. Cerci, as I learned, are two small projections at the rear of some insects. The book has a glossary and short chapters on insect structure and development, with illustrations, which help to learn how to use the binary key.
“Insects” has 400 pages with 1300 high-quality black-and-white illustrations and 142 color paintings, nearly as good as pictures for identification. Some argue that paintings and drawings are better than photographs, because with drawings one can “get to the essence” of the depicted insect. The current trend, however, is toward photographs. In any case, there is no question that “Insects” is a classic. It also includes a list of references, a comprehensive index, and information on collecting, mounting, and preserving your specimens. But if you want to know about cicadas in Las Vegas, “Insects” won’t help. The only cicadas covered are the eastern ones. I don’t view this as a problem with the book. There are so many different insects that any field guide must leave out huge numbers of them. One solution is to have several field guides, and hope the particular insect that one is interested in appears in at least one of the guides.
If you don’t mind learning how to use the binary key in “Insects,” there is really only one drawback to the book: it is out of date. This book has not been updated since 1970, and the past few decades have seen a lot of changes in classification of many species, including insects. For instance, our old friend the cicada was once classified in the order Homoptera, and that’s where “Insects” has them. The newer books put cicadas in the order Hemiptera, along with the “true bugs” (which now have a separate suborder, Heteroptera).
Granted, this is not a big concern for most people, and the topic probably won’t come up at the next party. (“Hear that cicada out there? You know, they used to be classified as Homoptera, but now cicadas are placed in the order Hemiptera! Isn’t that interesting? Hello? Why is everyone leaving?”) But if you’d like a more up-to-date field guide, and prefer photographs to drawings, then the National Wildlife Federation’s “Field Guide to Insects and Spiders of North America” by Evans, is for you. Arthur V. Evans, currently associated with the Smithsonian Institution, has done a stunning job of bringing a huge amount of information together. There are 1600 color photos covering “more than 940 insects, spiders, and related species” in nearly 500 pages. The photographs, showing the insects in their natural habitat, are simply beautiful. Like “Insects,” it has information on insect structure and development, collecting and preserving specimens, a glossary and index. But Evans’ field guide has even more, covering topics such as environmental issues and endangered species, how to keep live insects, macro photography, Internet resources, and even how to enhance your home garden to attract arthropods. There are also lists of zoos that have insect displays, other North American insect guide books, general interest books for further reading, web addresses of entomological and arachnological societies, and biological supply houses.
Instead of a binary key to identification, there are several pages of short paragraphs describing the different orders of insects. Once the correct order is found by description you can easily turn to the section of the book with pictures of the insects of that order, and with luck the insect you are looking for will have a photograph in the book, along with a description. At first this may seem even more daunting than a binary key, but in fact it isn’t bad. After trying the system several times one should be able to narrow down the search quickly. Any type of identification key requires a certain amount of practice.
Looking up cicadas in the index, one finds a possible candidate for a local species in Tibicen dorsata, or the Grand Western cicada. The range of this cicada is described as extending west into Arizona, but such a range could easily include Las Vegas at the extreme western end. Evans’ “Field Guide to Insects and Spiders” is a high-quality paperback, with a waterproof cover.
Another recent entry is the “Kaufman Field Guide to Insects of North America” by Eaton and Kaufman. Just as Roger Tory Peterson has his name on a series, Kenn Kaufman’s name appears on this book which was primarily written by Eric R. Eaton. Like the other two books this also covers non-insect arthropods. “Kaufman” has the friendliest-looking identification key of the three: species are grouped into thirteen categories, and pictures of representative specimens are to be compared with whatever flying or crawling thing you’re trying to identify. Kaufman also has an amazing number of photographs, more than 2350 in just under 400 pages. To get them all into the book, most show only the insect, with the background having been removed. As a result the photographs are not as striking as those in Evans. Kaufman does not have as much general information as the other two books. It does have a good index, and covers insect anatomy, development, classification and identification, but has no glossary. The manufacture of this book is the most durable of the three, with a stitched binding and a tough flexible cover.
Naturally there is some overlap, but Kaufman covers some insects not found in Evans (and vice versa). For example, the Cigarette Beetle (Lasioderma serricorne) which, according to Kaufman, “infests a variety of dried vegetable matter but appears most addicted to tobacco at all stages of production. So far, it has not been observed smoking.” The text on any one species is usually less than Evans has, but more species are discussed per page and the writing is lively and interesting.
Once more looking up cicadas, Tibicen dorsata is listed in Kaufman as being found in the south-central U.S., and west only as far as New Mexico. A different species, Cacama valvata, also called “cactus dodgers,” is listed as being found in the Southwestern U.S.; however, the cicada I saw looked more like the picture of Tibicen dorsata than Cacama valvata. Clearly, more research is needed.
You may find insects that the guides simply do not cover. I found an insect (see picture), possibly a Stiletto fly, that so far I’ve been unable to identify. (Update: BugGuide, see below, helped me narrow it down to some type of robber fly.)
No discussion of insect identification would be complete without mentioning some internet resources. BugGuide in particular has lots of pictures of insects, and if you upload a picture you might find someone who knows what your strange bug is. The Penn State College of Agricultural Sciences has an entomology website with both pictures and detailed information (it also has a link to BugGuide). Iowa State has an entomology index of Internet resources. The Internet has the potential of being the ultimate insect resource (it is already full of spiders! Okay, I apologize again…) with all the advantages and drawbacks we’ve come to know: websites could disappear overnight, or change their name, or on the other hand, they could contain even more information than a book. For now at least, it’s tough to beat a good field guide.
If I were getting only one field guide, it would have to be the beautiful and informative “Field Guide to Insects and Spiders” by Evans. Next would be the sturdy Kaufman book with its many photos, and my third choice the classic but outdated Borror and White. I’m keeping all three, because you can’t have too many insect field guides, if you really want to be informed.
More fun with bug identification here: Do you know what a Cotinis mutabilis looks like?