Caterpillars, before turning into butterflies and moths, remain in a cocoon from a few days or weeks to even a few years for some drought-adapted species. If you are raising caterpillars that have formed a cocoon, you may understandably become anxious as to whether the caterpillars are still alive. Fortunately, you can follow a few simple steps to find out.
Monitor the color of the cocoon. A cocoon from which a butterfly is about to emerge will either turn very dark or become clear. Overly dark cocoons, though, may point to death.
Gently bend the abdominal region of the cocoon. If the cocoon bends and stays bent, the caterpillar is probably dead.
Be alert if the cocoon does not stay bent. A butterfly is soon to hatch. Butterflies take only a few moments to emerge from their cocoons.
About the Author
Tricia Lobo has been writing since 2006. Her biomedical engineering research, "Biocompatible and pH sensitive PLGA encapsulated MnO nanocrystals for molecular and cellular MRI," was accepted in 2010 for publication in the journal "Nanoletters." Lobo earned her Bachelor of Science in biomedical engineering, with distinction, from Yale in 2010.