Helping people protect the local wild and scenic places they care most about.

Field Notes

Nature's Special Effects

When you think of special effects you probably think of Hollywood. But did you know that you can step out your front door and watch Mother Nature put on an even bigger show than moviemakers and stunt people?

Just look at what happens during the life cycle of a monarch butterfly: an egg hatches after about four days and it starts molting – shedding its skin – as it grows into a two-inch long caterpillar. It sheds its skin a total of five times in two weeks. Then, when the time is right, it transforms itself into a pupa within a matter of hours. In another 10-12 days, a butterfly emerges from its chrysalis.

Let’s take a closer look at all of those special effects. The monarch butterfly, Danaus plexippus, is sometimes called the “milkweed butterfly” because the larva will only eat this type of plant. Adult females lay their eggs on the underside of milkweed leaves so that when they hatch, in 3-10 days depending on the temperature, the larva (caterpillar) will have an immediate source of food.

The caterpillar feeds constantly for about two weeks on milkweed plants, shedding its skin as it grows larger, and then it turns into a pupa (chrysalis). When it pupates, a monarch larva splits its exoskeleton and wiggles out of its skin. When this skin moves far enough down the body, hooks from a silk pad attach the pupa to a branch, head down. The newly exposed pupa starts to dry and harden into a chrysalis, a process that only takes a few hours. Inside the chrysalis the caterpillar’s body is reorganized into a butterfly, which emerges after 10-12 days. In the final day or two before emergence, the chrysalis becomes transparent, and you can see the orange and black wings beneath.

Photo by www.learner.org

After it emerges, the metamorphosis is complete. The monarch butterfly inflates its wings with a pool of blood it has stored in its abdomen by pumping the liquid into wing veins. Then the wings dry while it rests for several hours.

The adults born in late summer to early fall migrate to California and Mexico to hibernate. They will return in the spring to lay eggs on milkweeds in southern states. These butterflies die in a few weeks, but their offspring fly to breeding areas in the northern United States and Canada. After several generations live and die over the summer, monarchs again begin the migration to the south.

It's amazing that this small, fragile creature changes so many times and in such a big way during its lifecycle. Mother Nature truly puts on a spectacular show, without any fireworks, stunt doubles or chase scenes!

Photos by Pamela Larson, except as noted.

Want to read past Field Notes' articles? Click here.

Home | Who We Are | Projects | Land Protection | Preserve Profiles
Education | Upcoming Events | How You Can Help | Contact Us