Moths’ Open-Weave Cocoons Adapted to Handle Heavy Forest Rains

Candice Gaukel Andrews October 8, 2013 9

In the rainforests of Peru, the average annual rainfall measures 79 inches. That not only creates lush, green jungles filled with a diversity of life but dangerous environments, too—especially if you’re a caterpillar aspiring to become a moth.

Most caterpillars construct tightly knit coverings in out-of-the-way places in which to undergo their transformations. However, this type of cocoon subjects the moth to the risk of drowning in its own shelter if water should seep into the top and begin to collect at the base. But some clever urodid moths have found a way to mitigate that danger. They weave net-like cocoons so that water easily drains out.

Watch the short clip below, titled A Ridiculously Awesome Cocoon, taken from the video series Smarter Every Day. The photographic shots of this mesh cocoon not only encourage us to seek the beauty of nature in small places but also in the tiniest of everyday events.

Here’s to finding your true places and natural habitats,





  1. Candice Gaukel Andrews October 18, 2013 at 3:56 pm - Reply

    Carter & Olivia,

    The butterfly farmer’s name is John Wahl. You might try contacting the Bronx Zoo, as it’s mentioned in the video that John supplies butterflies to that zoo. Or, t
    hese might be of interest to you:

    Thanks for the comment.


  2. Carter & Olivia Ries October 18, 2013 at 12:40 pm - Reply

    Great stuff. How do we get in contact with the guy in AL with the Butterfly Farm?

    Thanks for sahring

  3. mo norrington October 10, 2013 at 9:31 am - Reply

    Great little educational film. Thanks very much indeed for sharing it.

  4. Nicole Wexler October 10, 2013 at 9:30 am - Reply

    Wow, really beautiful and ingenious!

  5. Susan Sharma October 10, 2013 at 9:29 am - Reply

    Thanks for a most revealing post! We have so much to learn from butterflies and moths.

  6. Timothy Kerin October 10, 2013 at 9:29 am - Reply

    The cocoon looks like an elegant onion bag. I like the one-way escape hatch. The open structure conserves materials while as the commentary suggests, keeps rainwater from collecting and drowning the the pupa.

    Although the apparently delicate structure and large openings would seem to leave the pupa at risk for predation, the video creators didn’t go into how tough the cocoon fiber was, what the moth’s natural predators are or defensive mechanisms (such as bad taste or toxicity) which the pupa might benefit from. It would be interesting to know if the pupae are always found below the canopy as was the one in the video. This would subject them to some predators but keep them away from others.

    How about the single fuzzy string that suspends the cocoon? Assuming an ant was interested in eating the pupa, is there anything about the string that makes it difficult for an ant or other terrestrial insect to traverse, such as a microscopic stickiness? Just wondering…

  7. Steven Dammer October 9, 2013 at 5:11 pm - Reply

    That’s a really neat adaptation, although I am curious as to how it protects the pupa from other environmental factors or predators. I agree with what he said in the video, it really does seem counterintuitive to the survival of the pupa.

  8. Lawan Bukar Marguba October 9, 2013 at 1:55 pm - Reply

    Nature’s adaptation processes never ceases to wonder.

  9. Dhona Lovick October 9, 2013 at 11:46 am - Reply

    Nature never fails to amaze me, thank you for sharing

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