Tuesday, 24 April 2012

U for Urticating Hairs

Fun Facts:

1) Tempting as it may be, picking up nice fuzzy caterpillars may not be a good idea. The body surface of  some caterpillars, and a few adult insects, can be covered with urticating hairs. These urticating hairs are used as a defense mechanism against predation.

  © Copyright Pauline Eccles and licensed for reuse
under Creative Commons Licence


2) Urticating hairs can be broken down into two categories: Envenomating (venomous) and non-envenomating (irritating) hairs.

3) Envenomating hairs usually take on the form of sharp hollow bristles seated ontop of a fluid secreting gland. These hairs break under pressure, penetrate into the skin and release their fluid.  The fluid (usually a mixture of histamines) can cause irritation or inflammation. (source: http://medent.usyd.edu.au)

4) Non-envenomating hairs are easily dislodged when disturbed and can become airborne, settling on nearby surfaces. They are designed to produce a mechanical irritation that is often described as having similar effects of fibre glass particles on the skin. Coming into contact with these hairs usually results in a skin irritation. (source: http://medent.usyd.edu.au)

5) Urticating hairs can take many forms, they can be bristle-like seate or sharp-pointed hollow bristles, while others can take on the form of darts, long flexible tapering hairs, or rigid bristles.  

6) The urticating hairs can be arranged in a distinct pattern or tubercle, or they may cover the insect in its enterity. The location and structure of the hairs can be used as an identifcation tool. 

Have you ever had an allergic reaction to caterpillars? Ever handled a caterpillar and not have a reaction?


  1. Ah, the dreaded urticating hair. I know it well. I used to keep and breed tarantulas. The ones from Asia and Africa were not a problem, as they would just bite you without a second thought. But the ones from the Americas had the urticating hairs, but we're less prone to biting.

    I developed tiny itchy hives between my fingers. And like clockwork, you could guarantee somewhere around 5:30 - 6:00 am they would begin to itch. Very mildly at first, but as soon as you gave them a scratch, it would intensify. It would get to a point that you wanted to rip your skin off. Cold water helped, but I once accidentally ran warm water over my hands - it felt like liquid fire.

    I rehomed all my spiders, thankfully with the help of the British Tarantula Society.

    But to an animal (an human for that matter), the urticating hairs of a tarantula are designed to be flicked into the face of a predator. If these get into the eyes, they can cause permanent damage and sometimes blindness.

    Thank you for joining the hearth - I hope you find something of interest there :)

    PS: I like your photo - you remind me of a French actress, very classic b&w image.

  2. That music clip made me laugh so much, loved it.

    When I was courting my first husband (1974) his hair was longer than mine!!

    Last summer on one of the estates where my husband works they had an epidemic of what they knicknamed 'killer caterpillars.' They had to chop down an overgrown bush and these insects had developed into a colony. The workmen all came out in various rashes and in varying degrees.

  3. Urticating hairs - very cool!
    Aside from caterpillar poop, no I haven't had a bad reaction from handling one.

  4. I've only handled the non-hairy little green ones, I think. Never seen anything like your pictures in the wild in UK. Do they all have hair? Maybe with some, it's very short and fine.

  5. Mark: Sounds like a good idea relocating your spidy friends! (: I'm lucky I've never had any kind of reaction that resembles what you describe.

    Sally: LOL! Glad you like Hair. And 'killer caterpillars' makes me laugh. Though the workers probably didn't find it too funy if they had bad reactions.

    Mina: Caterpillar poop. :D Seriously where else could you talk about such things!?

    Nick: Love me the little green ones, HA! I also like the ones that inch up as they move, too funny. And no I don't believe they all have hair...but I'm not sure. Have a nice trip!

  6. I've picked up plenty a caterpillar in my day and never reacted, but it's good to know for my girls. I love earthworms and caterpillars... even ladybugs and butterflies. Just no ants, spiders, earwigs, scorpions, silverfish... eek!

  7. It transported me back to childhood days - when we played in the sand and were always stung by "hairy worms", as we called them.
    (I can't seem to access the video clip... will try again tomorrow.)

  8. I learned this lesson the hard way at an early age (about 8). YUCK!

    New follower here. I’m enjoying reading my fellow “A to Z”ers. I look forward to visiting again.


  9. Tia: I've picked up my share of caterpillar too and never reacted, but maybe I just haven't picked up the right ones!

    Michelle: It brought me back to my childhood as well, used to love poking caterpillars with sticks...poor caterpillars.

    Sylvia: Thank you for stopping in and commenting! I'm on my way to check out your blog now. Great to meet you!


Thank you for stopping by and leaving a comment!
Comments are the best. Well, the nice ones are. (:
I do my best to reply to everyone either via e-mail,
directly in the comment box or by leaving a comment
on your site. Chat with you soon!

Also, not interested in your spam. Really, I'm not interested.

J'écris, donc je suis (:

Related Posts Plugin for WordPress, Blogger...