Journey of a Monarch Butterfly
When you think about all of the amazing animals in this world, your mind tends to think about the large, furry critters, such as bears or moose. Yes, there are many crazy, cool critters in this world. In fact, there are about 5,000 mammals in the world.
But, at this time of year, when I think about amazing critters, my mind turns to the tiny and delicate Monarch Butterfly. Ya, that’s right, a butterfly! Sure, you might be thinking, butterflies are interesting, but are they really all that cool? I would respond with, oh yes, they are!
In late summer, the Monarch Butterfly preforms the first of several mind-bending behaviors. All of the Monarchs you are seeing in late summer are flying south in an unprecedented migration that no other insect performs. All of the Monarch Butterflies in the eastern half of the country are heading for the mountains of central Mexico, where they will spend the winter.
How this tiny winged insect manages to navigate thousands of miles to Mexico is still unknown. Millions of Monarchs spend the winter clinging to trees and taking short flights on warm winter days. Next spring, they leave Mexico and start to fly north, but they only make it to the southern border states, such as Texas. The Monarchs then mate and lay eggs, then they die, never returning to their birthplace.
Adult Monarch Butterflies only lay their eggs on milkweed plants. After mating, the female flits around and lands on a variety of plants. She drums the surface of the leaf with her front feet and can identify the kind of plant from the scent that arises from the drumming. If she is on a milkweed plant, she bends her abdomen around the edge of the leaf and deposits a tiny, whitish egg on the underside of the leaf. In a short time, the egg hatches, and a very tiny caterpillar emerges.
The caterpillars feed exclusively on milkweed plants. Inside the leaves and stems of the milkweed plants is a white milky sap that contains cardiac glycosides. For humans, these cardiac glycosides are a class of compounds that cause increased heart rate, increased respiration and a flushed feeling. In some cases, it causes nausea and vomiting. In short, the milky sap inside milkweed plants is toxic. However, the Monarch caterpillar eats the leaves and the toxic sap with impunity.
As the caterpillar grows and feeds more and more on the milkweed, the caterpillar itself becomes toxic, and is deadly if eaten by a predator, such as a bird. Eventually, the caterpillar matures and seeks out a sheltered spot to change into a butterfly. This is nothing short of mind blowing. The fully-grown caterpillar spins a silken pad in which it grabs a hold of and hangs down. Its body is slightly curved and looks like the letter J.
The skin on the back of the caterpillar splits open and slides off, leaving a bright green sac, at which point it is called a chrysalis. Inside the chrysalis, all the caterpillar’s cells liquefy and reorganize and regenerate to form a completely new life form, the butterfly.
In a short time, the Monarch Butterfly emerges from the chrysalis. The adult Monarch Butterfly flies northward following the spring weather. Along the way, the butterfly feeds and then mates. Each female lays upwards of 500 eggs before she will also perish. The next generation goes through all the same steps to become an adult. During summer, a third and fourth generation Monarch Butterflies go through the same process and eventually the Monarch Butterflies make their way to the northern tier states and into Canada. It is about the fifth generation of butterflies that will turn around and make the journey south back to Mexico where their great-great-great-great-grandparents started.
So, at this time of year, if you see a Monarch Butterfly, you know this amazing insect is on a mission to make its way back to Mexico. Without this migratory generation, we won’t have any Monarchs next year. What an amazing insect! Until next time…
Stan Tekiela is an author / naturalist and wildlife photographer who travels the U.S. to study and capture images and video of wildlife. He can be followed on www.facebook.com and twitter.com. He can be contacted via his web page at www.naturesmart.com.