Butterflies and Moths
Differences between Butterflies and Moths
Butterfly bodies are usually slim, whereas moth bodies can be husky and fuzzy. Moths hold their wings outstretched when they rest, whereas butterflies hold their wings upright, or vertically, when they rest. Another difference is in their antennae. Moths and butterflies use these antennae to detect chemicals in the air that signal the presence of the opposite sex. Moth antennae are feathery and extensive, as they have poor eyesight and rely heavily on chemical signals at night. Butterflies have knobby ends on their antennae stalks and use flight pattern and shape as additional aids in locating mates.
Several larvae (called caterpillars) of moths have stinging spines, and several species, including the common cabbage butterfly, are not native and multiply rapidly each year. These invasive caterpillars can do millions of dollars of damage to vegetable crops.
Many species of butterflies and moths overwinter in Georgia. They emerge on warm winter days and return to their shelters when the cold returns at night. These shelters can be rock outcroppings, fallen trees, tree bark, eaves of houses, barns, and even warm compost piles. Overwintering sites must have some warmth to keep the butterfly or moth from freezing. Butterfly boxes are not suitable for overwintering, but they do well as places for butterflies to hide during thunderstorms. Both butterflies and moths quickly find niches under tree bark, large branches, or overhangs of rocks when storms approach.
Caterpillars usually eat the leaves of only a few species of plants, and they eat only what plants their mother laid eggs upon. Non-native caterpillars, such as the cabbage butterfly, will eat literally dozens of garden plants, however. Caterpillars can eat their weight in food several times over each day.
Butterflies and moths hatch from their chrysalises and find mates quickly because their lives are short and full of predatory dangers from birds, spiders, lizards, and frogs. Mating takes place within days, and the female soon after lays eggs on a plant species. The caterpillars hatch and focus on eating for two to four weeks. Once they have grown to a mature size, they undergo metamorphosis. Moth caterpillars begin the process by either spinning a cocoon made of silk and natural debris or finding a protected place under leaves or stones. Butterfly caterpillars prefer to begin their process by attaching themselves to sticks or large leaves. The caterpillar places silk on a branch, clamps onto it with its hind legs, and then weaves a strand of silk near the head to hold it upright. Once in place, moth and butterfly caterpillars split their skins starting at the head, revealing a pupae underneath. They can overwinter in this form or develop into moths or butterflies within a few weeks, depending on the season.
Once the process has been completed, and the moth pupae or butterfly chrysalis splits, the developed insect can leave. In the case of moths that form cocoons, the silk strands must be cut or dissolved before the insect can escape. Once out, the insect must pump the fluids from its abdomen into the wings to expand them and then allow them to dry and harden. The moth or butterfly then begins to fly and seek a mate.
Broods and Population Dynamics
Another factor is the "range," or area of land, that the species occupies. Some of Georgia's butterflies and moths live only in the northern mountain valleys, and others live close to the coastal marshes. The species may be limited to certain areas by the presence of native food plants for the caterpillars or by environmental conditions needed by the insect to live comfortably. By knowing where each species lives, what food plants live there, and how far the insects travel, scientists can better understand their behavior and how the insects fit into the environment.
This information also allows scientists and butterfly enthusiasts to look for rare species at the right time of year or to monitor overall populations of these insects in a given area. Gardeners, who can attract species by growing plants that produce nectar or food for the butterflies, also benefit from this knowledge.
The eggs are laid, and the new caterpillars develop into adult monarchs within a five- week period. These adults then fly northward to such places as Minnesota, Pennsylvania, and southern Canada, where by that time a different species of Asclepias is just at the perfect stage for the caterpillars to eat. This generation matures, and by September the newly emerged adults begin their southward movement back to Mexico. They pass through Georgia again in September and October. Monarchs that live east of the Rocky Mountains generally migrate to Mexico. Those that live west of the Rockies migrate to the California coast near Monterey.
The top plants for attracting butterflies and moths to Georgia gardens are butterfly bush (Buddleia davidii), butterfly weed (Asclepias tuberosa), hardy lantana (Lantana camara), honey bush (Melianthus major), hummingbird sage (Salvia guaranitica), Mexican sunflower (Tithonia rotundifolia), passion vine (Passiflora), pineapple sage (Salvia elegans), purple cone flower (Echinaceae purpurea), southern lilac (Vitex), upright verbena (Verbena bonairiensis), and wild ageratum (Eupatorium coelestinum).
Geyata Ajilvsgi, Butterfly Gardening for the South (Dallas, Tex.: Taylor Publishing, 1990).
Jaret C. Daniels, Butterflies of Georgia: Field Guide (Cambridge, Minn.: Adventure Publications, 2004).
W. J. Holland, The Butterfly Book: A Popular and Scientific Manual, Describing and Depicting All the Butterflies of the United States and Canada, rev. ed. (Garden City, N.Y.: Doubleday, Doran & Co., 1931).
W. J. Holland, The Moth Book: A Popular Guide to a Knowledge of the Moths of North America (New York: Dover Publications, ).
Robert Michael Pyle, The Audubon Society Field Guide to North American Butterflies (New York: Knopf, 1981).
Amy Bartlett Wright, Peterson First Guide to Caterpillars of North America (Boston: Houghton Mifflin, 1993).
Paul A. Thomas, University of Georgia
A project of the Georgia Humanities Council, in partnership with the University of Georgia Press, the University System of Georgia/GALILEO, and the Office of the Governor.