I recently had a discussion about Monarchs with my son and a friend. They made a comment about all the baby Monarchs stuck to the front of their car and the masses fluttering through the air. I can understand the confusion, as many butterflies look similar to Monarchs. But, there is no such thing as a baby butterfly. That would be called a caterpillar.
The small orange and black butterflies they were seeing are American Snout Butterflies named after their long-nosed snout. They hold their own place in South Texas legend for their mass migrations but I’m going to stick with Monarchs for this article.
The Monarch is one of the most recognizable and celebrated butterflies in North America. This beautiful, Halloween-like colored orange and black butterfly can be seen in South Texas in the spring and fall during their migration. Monarchs can be found in nearly any open landscape and will even frequent backyard flower gardens
Males can be distinguished by a small black spot on a vein on the hind wings. Monarchs are known for two amazing acts in nature, one - a transforming metamorphosis, egg to caterpillar to pupa to adult, and two - a generational cycle that involves migrating nearly 3,000 miles.
Adult Monarchs will feed on and pollinate a variety of flowering plants but a vital component in their life cycle is the host plant. A host plant is a plant species that a butterfly must have as a food source for its caterpillars, whereas a pollinator plant is a food source for adult butterflies.
Different species of butterflies use different host plants. In the case of the Monarch, only milkweeds are host plants. Life begins as an egg laid on a milkweed plant. Soon after, a tiny white, black and yellow striped larva or caterpillar emerges. The caterpillar feeds on milkweed nearly non-stop and rapidly grows. As it outgrows itself, it will shed its skin and emerge as a larger caterpillar.
The stage between the molt is called an instar. Each time the caterpillar goes through this cycle, it grows larger. This process will continue for a total of five instars. At the end of the fifth and final instar, the caterpillar prepares to form into a beautiful chrysalis.
This begins with the caterpillar moving away from the host plant and finding a suitable place to hang in the shape of a “J.” While hanging in the “J,” the caterpillar begins to split out of its skin from the bottom up. What emerges is nothing short of amazing. From inside of the caterpillar comes a bright green chrysalis adorned with beautiful golden spots. This entire process takes about six minutes
Another incredible act of nature takes place inside of the chrysalis. From what has been described as green goo by some butterfly specialists, a transformation is taking place as the tissues are re-organized to form a butterfly.
A day or so before emerging, typically 8-11 days, the chrysalis turns translucent. Shortly after that, an adult Monarch splits out of its casing. The adult butterfly pumps fluid into its wings to expand them and after a few hours, the wings dry and the butterfly is ready to take flight. The entire process, from egg to adult butterfly, takes four to five weeks.
Unlike some butterflies, Monarchs do not over-winter in the northern latitudes. In fact, they take part in another one of nature’s wonders. Monarchs from the Eastern U.S. and Canada migrate a 3,000 mile trip to winter in Mexico. These same butterflies return to the Southern U.S. in the spring to mate and continue the generational cycle.
It takes four generations of Monarchs to complete their travels. The first generation born in the spring followed by the second and third only live for four to five weeks. Each generation continues a northward movement until the fourth generation. Only the fourth is long-lived, approximately ten months and migrates back to Mexico to begin the cycle again.
Over the past several years, Monarch populations have declined. There are several factors suspected including such things as habitat loss and decline in the all-important host plant, milkweed. Growing native pollinator plants, especially milkweed, is one thing that we can do to help the Monarchs and other species of butterflies as well.
Milkweed plants provide nutrition for Monarch caterpillars but also contain poisonous cardiac glycosides. Monarchs evolved the ability to assimilate milkweed toxins, making them unpalatable to most predatory animals.