Hobbies And Interests
Things You'll Need
Instructions
Look at the insect's general body shape and compare it to the illustrations in the field guide. Differences in basic form can be very obvious, as with distinguishing between a grasshopper and a bumblebee--the former with its humped back and strikingly long rear legs, the latter with its round, fuzzy body. Sharper distinctions can be made, too: Swallowtails and metalmarks are both butterflies, but the former have proportionately larger, more convoluted wings compared to the latter.
Compare the insect's color and pattern with the pictures. These marking characteristics--usually both decorative and functional--are some of the most powerful diagnostic tools, and truly demonstrate the helpfulness of reference illustrations. The impressive yellow body and black markings of the goldenrod soldier beetle of eastern North America will draw your eye both on the ground and in the pages of a field guide: it's easy enough to flip through those pages and quickly zero in on likely candidates.
Key into other notable physical features of the insect to compare with your reference. The big, crooked rear legs of water boatmen--aquatic insects that "row" themselves across the surfaces of ponds and streams--are an example of a defining anatomical characteristic. Wispy, gangly legs belong to both crane flies and mosquitoes, but with side-by-side illustrations you can pick out the notably enlarged proboscis of the blood-sucking mosquito.
Use the illustrated range maps in insect field guides, when provided, to further hone your identification. The dizzying magnitude and variety of insect species even on the regional level make these visual aids somewhat less useful than in the case of birds or mammals, but they may still be of service. For example, examining a huge and tawny moth in a riparian thicket in Montana, you should be able to exclude the regal moth from your consideration because this giant only lives farther east. A more likely candidate would be an imperial moth.