Horseshoe SOS | Naturedigger

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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Horseshoe SOS

Horseshoe SOS is a comprehensive guide to everything you ever wanted to know about horseshoe crabs, including: anatomy, conservation efforts and the controversy surrounding use of their copper rich (blue) blood. There is also an FAQ to answer all of your most pressing horseshoe crab questions. The app also allows you to easily report tagged horseshoe crabs (or separated tags) to the US Fish and Wildlife Service simply by opening the app and choosing the Report Tag button on the navigation screen.