The caterpillar is the immature stage of the butterfly. Its job is to eat and grow, eat and grow. I found much exaggeration in popular writings as to the quantities butterfly caterpillars eat. My garden did not suffer by their presence.

Caterpillars have an exoskeleton, which means they can grow only so much until that exoskeleton becomes too tight. Then they have to grow a new and bigger exoskeleton underneath the old one, which is shed in a process, called molting, or ecdysis.

When the time has come to molt, the caterpillar lays down a layer of silk that will hold it in place until it has moved out of its old exoskeleton. When the new exoskeleton has hardened, the caterpillar will turn around and eat the old skin. This process of molting is repeated several times throughout its larval stage. The time between each molt is called an instar. The last molt turns the caterpillar into a chrysalis, or pupa.

When ready to pupate, the caterpillar will lay down a heap of silk with spinnerets located at its mouth. Then it turns around and, after some maneuvering, will press its tail-end against the silk to secure a good bonding, with the anal prolegs holding on to keep it from falling. It will swing some and then take its time to finish producing a new skin under the old one. This new skin will become the shell of the chrysalis. Inside the chrysalis, the caterpillar turns into an adult butterfly that will come tumbling out in due time.

Before long, the chrysalis will crack open and I'll experience indescribable enchantment. This change of form from caterpillar to butterfly seems to me to be the most remarkable thing in nature. To have seen a caterpillar change itself into a chrysalis and then to reappear as a beautiful butterfly is sheer magic and is an experience never to be forgotten.

NOTE: I have given no times for the different developmental stages because they vary so much with environmental conditions, especially temperature. The Gulf Fritillary is a sub-tropical butterfly and does not have a diapause, a period where all activity stops. It just slows down when the temperature lowers and speeds up when it gets warmer regardless of which stage it is in. For instance: an egg may hatch within three days in the heat of summer (remember this is Tucson), and it may take several months for the adult to develop in the chrysalis in the winter.

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