Biology of a monarch
The differences between the male and the female can be distinguished by looking at their hind wings. Males have an additional black spot on the lower section of their wings, while the female does not. The female also has noticeably larger black veins on its wings.
The Monarch Butterfly
Life Cycle
The life cycle of the monarch butterfly is approximately 37 days. The egg stage is 3–5 days, the larva stage is 11–18 days, and the chrysalis stage is 8–14 days until it emerges and becomes an adult.
The development rates of the butterfly are temperature dependent. Monarchs develop more quickly in warm temperatures and more slowly in cool temperatures.
Monarch Migration
Monarch butterflies migrate north each summer and then in autumn return along the I-35 corridor through the central United States to their overwintering sites in central Mexico.
In February and March, after hibernating in the Mexican mountains, monarchs begin to travel north. They start arriving in Duluth in late May.
After mating and laying eggs in the southern United States, these monarchs die, and their offspring continue to travel north. This is the first generation.
Generations two and three are born in the midwestern United States, and along with generation one, will only live 2–6 weeks.
By fall, the fourth generation has made its way to the northern United States and Canada. This fourth generation—often called the Super Generation, are the great-grandchildren of the overwintering monarchs and can live up to eight months. This generation does not reproduce at this time but instead uses its energy to migrate the 3,000 miles to Mexico where they will spend the winter.
This cycle continues year after year and has been called one of the most spectacular natural phenomena in the world.
Monarch butterflies in Mexico’s oyamel fir forest.
Interstate 35 from MN to TX happens to be the main flyway for monarch migrations and is being designated the Monarch Highway.
