Tips for identifying insects, spiders


People who create a backyard wildlife habitat invariably become interested in what comes to live in it. It’s not over once the plans are made, beds are dug, plants are planted, and a new bird feeder is hanging from a tree limb. Every day becomes a new page in their mental log of what’s happening “out there.” When they’re “parenting” a whole new, vibrant ecosystem, every animal in it becomes “somebody.”

Some of these people surprise themselves by becoming interested in more than birds and squirrels, but all manner of critters — even insects and spiders. You may be one of these people! If you’re observing your yard closely, you’re noticing that insects and spiders are everywhere: in the air, in shrubs, on flowers, clinging to the side of your house, hanging from the porch ceiling, floating on water, shuffling under yard debris or moving in and out of the ground.

If you’ve already tried, you’ve found that identifying insects and spiders (spiders aren’t the same as insects) is tough. It requires real expertise to determine the exact species of most of them. With more than 100,000 insects and 3,000 spiders in North America alone, determining the name of an individual specimen can be daunting. The good news is that with only two or three hours of study you’ll know how to narrow the field down to the order most insects belong to. Once you can do that, it’s a matter of whether you want to do further research to pin down the exact name of a species, or not.

Familiarity is the key. The more you read and study photos, the better you’ll get at narrowing down the field. This web site and many others on the internet, along with insect field guides and your local library are invaluable resources.

It’s a good idea to snap a picture of insects that interest you. It really helps when you can refer to a photo again and again. This also will allow you to make use of the most valuable resource of all: the experts at Upload the image of your mystery insect and they’ll help you identify it.**

To help you get started, each of the insects listed in the side column of this page links to the order they belong to. There you’ll find general characteristics for that group. Time spent learning about insect orders is well spent. Some insects are obvious, and some just seem obvious.

What is an order?
You may be wondering where an “order” fits into scientific classification. Officially called taxonomy, scientific classification is the grouping of insects (and all other living things) into batches of similar organisms. The system is complex and seems to routinely undergo challenges and upheavals as new technological capabilities, like DNA analysis, keep taxonomists busy sorting and re-sorting, particularly with insect species. Not only that, but new species are being discovered all the time, adding to the system’s already humongous catalog of over one million described insects. Fortunately, we laypeople can ignore the rocking and roiling and arguments between experts, except to be aware that an insect’s classification is subject to change.

Here’s an example of how scientific classification works, using a single insect species, Coccinella septempunctata, a lady beetle, or “ladybug.” Its classification, as with all insects, starts in a broad category that includes all animals, based on characteristics they have in common. Then it drills down in increasingly specific terms until no other insect group on earth matches the precise physical description of Coccinella septempunctata.

Most insects are inconspicuous and go completely unnoticed by us. Of interest only to experts, they’ve never been given a common name. This pretty beetle has one, though: It’s the Seven-spotted Lady Beetle, shown at the top of this page. This species is widespread in North America and there’s a good chance it visits your own backyard wildlife habitat.

Hierarchical ranking for Coccinella septempunctata and the characteristics that placed her at each level:

Domain: Eukaryote (cells with membrane-bound nucleus=humans, plants, etc.) Kingdom: Animalia (multi-cellular, must eat for energy)
  Phylum: Arthropoda (hard exoskeleton, segmented body, jointed limbs)
    Subphylum: Hexapoda (six legs)
      Class: Insecta (3 distinct body regions, two antennae, compound eyes)
        Subclass: Pterygota (Winged insects)
          Order: Coleoptera (Beetles)
            Suborder: Polyphaga (Rove, scarab, leaf beetles, other kinds)
              Superfamily: Cucujoidea (Flower, Flat bark, Lady beetles)
                Family: Coccinellidae (Ladybird beetles)
                  Genus: Coccinella
                    Species: septempunctata
(Genus and species, by custom, are always displayed in italics.)

*Top photo: Gilles Gonthier / Flickr; (cc by 2.0)
**For other animals: Study the animal’s appearance as much as possible and write down what you saw, while it’s still fresh in your mind. It’s even better if you can quickly snap a digital photo. With or without a photo, turn to one of your field guides, go online to sites dedicated to animal identification, call your local City Naturalist, or contact your state’s Department of Fish and Wildlife. Email’s a wonderful thing – many experts will let you email your photo to them for a quick ID.