The Monarch arrives just outside our yard, flying so gracefully with its beautiful, and miraculous body, taking its large, brightly colored wings, making us all in awe. Some wonder the characteristics of their body and how they were formed in the first place. This magnificent butterfly goes through three different stages before it becomes its adult stage. First as an egg, the larva, pupa, and finally an adult. 

  

The Egg: Layered with a hard outer shell to protect the larva development stages. Ridges are formed on the shell before the female lays the egg. 

Larva: The caterpillar has six eyes, but they are weak, so the antennae play a role to help direct food into the larva’s mouth. The thoracic and abdominal segments on a monarch hold jointed and prolegs, in which the prolegs help the caterpillar stick to the leaf. The spiracles on the side of the abdomen and thorax provide oxygen circulation throughout the body. 

Pupa: The exoskeleton of the larva splits and the body moves down the cremaster, in which the larva spins a silk pad so that the cremaster allows the monarch to hook onto it. They start molting again and the skin hardens in the form of a green chrysalis.  Within about 12 days, the chrysalis becomes invisible and a butterfly emerges. 

Adult: When the adult comes out of its cocoon, liquid gets pumped into the wings vein which inflates it then dries out. Their compound eyes detect light and images. The antennae give them a sense of smell and the proboscis is a tongue allowing it to suck water and nectar for food. The wings on the monarch can be moved by changing the shape of its thorax. 

The Stages of a Monarch Butterfly

 

Citations: 

       Lovett, Jim. “Monarch Watch : Biology : Anatomy.” Monarch Watch : Biology : Life Cycle, www.monarchwatch.org/biology/.