There may be no more widely recognized butterfly than the monarch (Danaus plexippus). With its easily identifiable caterpillar, beautiful pale green and gold chrysalis, and its distinctive coloration as a butterfly, the monarch may be the butterfly most familiar to people in North America. Its migration to Mexico is the stuff of legend, and many a scientist has spent a lifetime studying its fascinating behavior.
Milkweed is the sole source of food for monarchs as caterpillars. As butterflies, they consume liquids such as nectar.
North and South America, Hawaii and Australia
Monarch butterflies go through four or five generations each year. The adults of fall migrate to Mexico – this is the case for nearly all monarchs east of the Rocky Mountains - where they overwinter in what some consider to be one of the wonders of the natural world. The number of monarchs making this trip seems to be declining. Conservationists are hoping the population rebounds. While the reasons for the decline are being studied, one thing everyone can do is plant more milkweed plants to support the monarch larvae. Some organizations participate in monarch tagging programs to try to better understand the monarch life cycle.
While the monarch’s coloration looks beautiful to us, for predators it is a warning sign that the monarch tastes bad and may be poisonous. The milkweed they eat as caterpillars is loaded with heart toxins that most insect predators (birds, lizards, etc.) cannot handle. And even after metamorphosing into a butterfly, the insect still retains these chemical defenses.