Nymphalidae (brushfooted butterflies)
Monarchs are well-known butterflies distinguished by their relatively large size, rusty or orange wings with black veins, and black bodies. The upper surfaces of the wings are rusty or tawny orange with black veins; the wing edges are black with small white spots. The undersides of wings are lighter orange or yellow-brown. The veins are darker on females, and males have a black spot on their hindwings.
The caterpillars are white with black and yellow bands; the head is white with yellow and black markings; a pair of long, black filaments are on the thorax and a shorter pair near the end of the abdomen. The caterpillars are usually are found on milkweeds.
Wingspan: 3½–4 inches; larvae can grow up to 2 inches long.
Monarchs are found in a wide variety of habitats: fields and grasslands, roadsides, and urban and suburban plantings. They are famous for their annual migration to overwinter in Mexico. A variety of factors are causing the numbers of this famous species to decline. Efforts are under way to protect this species and restore its habitat. Missourians are encouraged to plant milkweeds for the larvae and flowers that supply nectar for the adults.
Monarch larvae feed on a variety of milkweeds, which contain cardiac glycosides. These chemicals are stored in the insect’s body and render it unpalatable and toxic to many predators. The bright color patterns of both larvae and adults advertise their toxicity to would-be predators. As adults, monarchs consume the nectar of a wide variety of flowers, particularly New England aster and other members of the sunflower family.
Declining throughout North America and may soon have protected status. Habitat loss in their overwintering territory in Mexico is one cause. Also, herbicide use throughout North America has been eliminating milkweeds, their required food plant. Especially in the Midwest, herbicide-resistant strains of crops allow farmers to eradicate nearly all weeds, including milkweeds, across vast areas, eliminating places for the monarch to breed. To conserve the monarch, we must allow milkweeds to grow.
Broods are produced in Missouri in summer and fall. Adults migrate to Mexico in late summer and fall; then, when they fly north in spring, they reproduce in Oklahoma or Texas. Their offspring continue northward, returning “home” some generations later. Eggs are laid in the spring and summer and hatch in about 4 days. The caterpillars eat milkweed. After about 2 weeks, the caterpillar enters the chrysalis stage. The mature butterfly emerges in about 2 weeks.
Monarchs are popular with gardeners and nature watchers. Educators commonly raise monarchs as a way of teaching about insect life cycles. Where they flock in great numbers, monarchs can contribute to the local tourism economy.
Monarchs play an important role in all the ecosystems pass through during migration. Despite the monarchs’ general toxicity, some predators can eat them. Additionally, they developed as Müllerian mimics with the similar-looking viceroy butterfly, each mimicking the other’s warning coloration.
Butterflies, skippers, and moths belong to an insect order called the Lepidoptera — the "scale-winged" insects. These living jewels have tiny, overlapping scales that cover their wings like shingles. The scales, whether muted or colorful, seem dusty if they rub off on your fingers. Many butterflies and moths are associated with particular types of food plants, which their caterpillars must eat in order to survive.