Monarch caterpillars molt (shed their skin) five times throughout their larval stage. The "skin" that is left behind is actually the caterpillar's exoskeleton. An insect's skeleton is on the outside, as opposed to on the instead like mammals, fish, reptiles, amphibians and birds. Endoskeletons provide support inside the body in the form of bones and cartilage, whereas As caterpillars grow, their exoskeleton gets too tight, so they need to shed it in order to continue to grow. Each molt results in a new "instar" stage. Therefore, when the egg hatches, that tiny 2 mm caterpillar is in its first instar stage.
It will molt three more times and grow exponentially over a couple of weeks. Each stage lasts 3-5 days. The fifth and final molt is when the fifth instar caterpillar becomes a chrysalis.
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Our iOS Apps
Pacific and Atlantic Poison Oak
Pacific Poison Oak
(Toxicodendron diversilobum)
Below are identification slides for Pacific poison oak which include leaves, flowers, berries, aerial roots, growth habit and habitat. All of these slides are included in the Rash Plants app as well as dozens of additional Pacific poison oak photos. You can download the Rash Plants app for free on the App Store.
Scroll down for Atlantic poison oak identification.
Atlantic Poison Oak
(Toxicodendron pubsescens)
Below are identification slides for Atlantic poison oak which include leaves, flowers, berries, growth habit, and habitat. All of these slides are included in our Rash Plants app as well as dozens of additional Atlantic poison oak photos. You can download the Rash Plants app for free on the App Store.
