Life Span: 0 - 1 years
Also Called: milkweed butterfly
The monarch butterfly is an attractive insect that has reddish-orange wings, with a black border and white spots along the edges. Male and female monarchs look very much alike, except for their scent glands. The male's scent glands are marked with dark scales in the middle of the hind wings, while the female's scent glands have broad black lines.
The monarch is also called the "milkweed butterfly" because during the larval (or caterpillar) stage it eats the milkweed plant. This makes them poisonous and awful-tasting to their predators, because toxins from the milkweed build up in the monarch's body. The adult butterfly lives on the nectar it gathers from flowers.
Monarchs can be found all over the world, but it's found most often in North, Central, and South America. It lives in open fields of milkweed during the spring and summer months, and in areas with lots of trees to perch on during the winter.
The monarch doesn't have many predators, for they are not a very tasty meal at all. Birds are probably the worst threat, but because of the toxicity built up in the monarch caterpillar's body from eating milkweed, most birds cannot tolerate eating them. Likewise they avoid eating the adult butterfly as well. Some predators that still dare to attack the caterpillars are parasitic wasps and flies, because they have developed a resistance to the toxins.
Much like some species of birds do, the monarch migrates south to warmer climates in the fall, when the weather begins to get colder in North America. Huge numbers of monarchs may migrate together. They spend a few months clinging to the branches of trees in places such as Florida, Texas, California, Cuba, and in the mountain forests of Central Mexico. When spring comes they make the long trip back north again, laying eggs along the way back when stopping for rest.
The monarch breeds four to five times in a year. The adult females lay approximately 400 eggs on the underside of milkweed leaves. The eggs will take about 3-15 days to develop, and change in color from yellow to light gray. Then the eggs hatch and the larva, or caterpillars, emerge. When they first hatch the caterpillars are only 2 millimeters long, but they eat constantly and grow quickly, shedding their skins several times in the process. By the time a caterpillar is ready to move to the next stage in its life cycle, it is about 2 inches long. When it's time for the caterpillar to pupate, it hangs upside down from the underside of a twig or leaf. It sheds its outer skin one last time, and transforms into a pupa or chrysalis. In about 2 weeks the adult butterfly emerges from the chrysalis, and rests. Once its wings are expanded and dried completely, it flies away. From egg stage to adult stage 8 or 9 months will have passed, although the monarchs that hatch in the spring or summer may live only 4 to 6 weeks, depending on the temperature and climate they are born into.
Adult butterflies (as well as caterpillars) don't have lungs or noses; they breathe through several tiny openings along their sides called "spiracles". They smell with their antennae and the bottoms of their feet, and taste with their tongues (which they also use like a straw to suck up nectar). They communicate by using "pheromones", or chemical signals.