ELI5: Why is the puss caterpillar so venomous, but the adult moth it turns into is completely harmless?

r/

The puss caterpillar is covered in venomous spines that can mess you up just by touching it. But then it turns into this soft, fuzzy little moth (the Southern flannel moth) that doesn’t have any defenses at all.

So how and why does it start off so dangerous and end up so chill?

Comments

  1. fiendishrabbit Avatar

    A caterpillar is basically a big bag of protein that has limited mobility. It’s going to spend a lot of time as a caterpillar. It pays off to invest in some defenses, like annoying hairs and toxins.

    A moth is highly mobile, lives for just a few weeks and only has one goal. Find a partner and create some offspring. So when weighing the cost vs benefit of producing the complex proteins that toxins are the ups&downs are completely different.

  2. GodzillaFlamewolf Avatar

    Poison is the caterpillar’s defense. Moth doesnt need it as it flies. Flight is the moth’s defense.

  3. Lethalmouse1 Avatar

    Caterpillar scoots in a way to be the ultimate prey on every level. 

    Moths can fly which is a decent defense against a lot of attacks. And the energy it takes to produce things in a body vs it’s reward levels and other things are a balance in nature. 

    Having flight is pretty energy intense and it’s better to put the resources into that than to have extra bristles with poison. 

    (On an ethereal level, a flying pain pill would be a menace lol.)