Brenda M. Griffith, age 13, of Tulsa, Oklahoma, for her question:
How many butterfly species are there?
Entomologists hesitate to give a precise answer to this question for several reasons. There are no guaranteed rules to distinguish the butterflies from the moths and some species show features of both. The classification of the teeming insect clan is an enormous task and experts suggest different grouping arrangements. Furthermore, several thousand previously unknown insects are identified each year. The lists grow longer and chances are that last month°s count of the butterflies is out of date.
Non experts find it hard to distinguish the butterflies from the moths and certain butterflies with moth like features tend to baffle even~the experts. But nobody is likely to confuse the moths or the butterflies with any other members of the teeming insect class. Their velvety wings qualify them for membership in the glamorous Order Lepidoptera. To date, about 140,000 of these fairy like creatures have been counted and identified one by one. By summer°s end, you may be sure that roving entomologists will add a number of others to the list.
The term "lepidoptera" is coined from older words meaning "scaly wings." It may not be as gorgeous a name as these beauties deserve, but it gives a clue to help classify them. A good microscope reveals that the powdery velvet is made from infinitesimal scales. This feature qualifies an insect as a member of lepidoptera. The large order is subdivided into families, genera and species, and only an estimated 10,000 of them are classified as butterflies.
Etomologists use various systems to classify the butterflies and the number of families may be stated as anywhere from six to 12. Some suspect that the 1,000 or so frisky little skippers merit a separate group of their own because they have both moth and butterfly features. But let's include. them, if only to boost the butterfly brigade. The others are classed in families mainly on the basis of their forms and colors.
The swallowtail family includes those big beauteous creatures with swallowtail tips on their hind wings. The sulphur and white family favors tones of yellow and elegant markings seen on the white cabbage butterfly. The swift, smallish blues and coppers favor showy checks and speckles in modest tans, enhanced with bright blues and golds. The group of metalmarks wear vivid iridescent spots. The brush foot family includes the painted ladies, the dark velvet mourning cloak and dozens of common but pretty butterflies. The medium sized fritillaries favor orange or red and often wear silvery spots on the underside of their back wings.
If we include the skippers, and most etomologists agree that we should, perhaps we can count around 10,000 butterfly species. But this estimate is far from precise and the number of known species may be closer to 20,000. In any case, before we have finished counting them one by one, more will be added to the list. However, it is not likely that the butterflies will ever equal the number of moth species.