Monarch Butterfly Lifecycle
Monarchs are a familiar butterfly to all, from kids to grandparents. With a wingspan of nearly 4 inches and easily recognized by the black, orange and white pattern, monarchs are unique in the butterfly world.
The monarch's life cycle is especially fascinating. However, the monarch population is declining and scientists are concerned if actions aren't taken to reverse the decline, monarchs may disappear forever.
- The eastern population of monarchs overwinter at the Monarch Butterfly Biosphere Reserve, a rugged forested mountain area in Mexico about 60 miles northwest of Mexico City.
- These adults migrated up to 3,000 miles from the northern United States and Canada the previous fall.
- From November to March, they cluster together on trees to stay warm, sometimes by the tens of thousands on a single tree.
Annual Migration/Reproduction Cycle
(North Dakota to Mexico Migrants)
- Generation 1: The adults that overwinter in Mexico leave the reserve in March and head north to Texas and the southern United States, mate and lay eggs, and it is these offspring that continue the journey north as adults. Consider these the Generation 1 monarchs, or the children of the monarchs that overwintered.
The Generation 1 adult monarchs continue moving north to the Corn Belt states and all over the eastern U.S., with some reaching North Dakota in late May.
- Generation 2: So now it's late May in North Dakota, and the Generation 1 adults have mated and laid eggs. These offspring are Generation 2 and are the grandchildren of the overwintering monarchs. They will become adults sometime in June, mate and reproduce, and their offspring are Generation 3, or the great-grandchildren of the overwintering monarchs.
(Note: Female monarchs only lay eggs on milkweed species. In North Dakota, the primary milkweed species they seek are common milkweed and showy milkweed, which are both native wildflowers in the state. Butterflies undergo complete metamorphosis, in which there are four distinct stages: egg, larva (caterpillar), pupa (chrysalis) and adult.)
- Generation 4: The Generation 4 monarchs enter a state of reproductive diapause, meaning their reproductive organs remain in an immature state so they do not reproduce. Somehow, these monarchs, which are 4 generations removed from their ancestors, migrate in September and October from northern breeding grounds, all to the same forest reserve in Mexico where they've never been before. The same place that their great-great grandparents left 6-7 months ago.
It's an amazing process in nature that is teetering on the edge of extinction. The monarch population has declined from a high of almost 1 billion monarchs in 1996 to a low of 35 million in 2013. There many factors that contribute to the decline: disease, illegal logging in the Mexican wintering grounds and predation. However, the primary concern is loss of habitat, such as CRP and native prairie, where monarchs can find both milkweed for the caterpillars and adult nectar food sources.
Because of the decline, the monarch has been petitioned to be listed under the Endangered Species Act. The monarch is a species that every citizen can help bring back, from planting backyard butterfly gardens, to leaving some roadside patches of milkweed unmowed, to keeping CRP on the landscape. Find out more about monarchs, other pollinators, and how you can help here.