Monarchs undergo a complete metamorphosis, or change, as they grow. The four distinct stages include the egg, larva, pupa, and adult. Hormones trigger the changes that take place from egg to adult over the course of a month. Adult monarchs live two to six weeks in summer. Those that migrate live all winter, or six to nine months. Here is what happens at each stage of the monarch life cycle.
- Egg — Female monarchs lay their eggs on milkweed leaves, the host plant, which will be food for the caterpillars when they hatch. The eggs are tiny, like a pinpoint and are typically white or yellow. The eggs hatch about four days after being laid on the leaves. The eggs are formed inside the female before fertilization. Depending on temperature, monarchs stay in the egg stage for three to eight days.
- Larva — The larva or caterpillar stage is when the monarchs do all their growing. They feed on the milkweed plant, only taking short rests. When the caterpillar becomes too large for its skin, it molts, or sheds its skin. The caterpillar often eats the shed skin before eating more plant food. Under normal summer temperatures, this stage lasts from nine to fourteen days.
- Pupa — When they are ready to pupate, the larva spins a silk mat to hang itself upside down. Wings and other adult organs are developing and transformation is completed during this time. The butterfly pupa stage is also called a chrysalis. Right before the monarchs emerge, you will begin to see their black, orange and white pigmentation. Under normal summer conditions, this stage lasts eight to fifteen days.
- Adult — When monarchs are three to eight days old, they mate so they can reproduce. Their main job is to perpetuate the next generation. Mating can last for up to sixteen hours, after which females begin laying eggs. Both male and female monarchs can mate several times during their lives and typically live from two to five weeks. Every year, the adults that emerge in early fall migrate to overwintering grounds in Mexico or Southern California. These adult monarchs can live up to nine months. To distinguish the male from the female, look for the black spot on a vein on each hind wing. The males also have wider veins on their wings.
Also known as the king of butterflies, the monarch is widely considered the most beautiful. In order for this majestic creature to survive, it must have access to the milkweed plant. You can do your part by enhancing your home garden with milkweed or by getting involved with seed collection.