Gossamer Tapestry

Reflections on conservation, butterflies, and ecology in the nation's heartland

Wednesday, May 28, 2008

How Many Legs Does a Caterpillar Have?


Looking at this picture, you might conclude that caterpillars have 8 pairs of legs- three pairs in the front, four in the middle and one at the back (if you're a bit confused, the head of the caterpillar is on the left in this photo). But wait, aren't caterpillars insects? Don't insects have 6 legs, not 16? Like all insects, this caterpillar has only 6 legs. Note the different shape of the three pairs of legs near the caterpillar's head. They're the legs. The remaining structures are not true legs at all. They're protrusions from the caterpillar's abdomen called prolegs. Much like true legs, they help the caterpillar grip onto surfaces like twigs, and aid in locomotion.

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18 Comments:

At 09:19, Blogger butterfly girl said...

That is really interesting! I feel smarter now.

Really.

 
At 13:55, Blogger Floridacracker said...

Nice photo and good clear explanation.
Just catching up ... the insect and flora shots below are great. Is that a bright green assassin?

 
At 17:16, Blogger cedrorum said...

Great post for the entymoloygically challenged like myself. Great photo.

 
At 18:57, Blogger Lemuel said...

I did not know that. Thanks!

 
At 20:39, Blogger T.R. said...

What does this particular caterpillar grow up to be?

And can I call this protrusion from my abdomen a pro-leg? "Have you gained weight" "No, its just my pro-leg".

 
At 23:49, Blogger Ur-spo said...

i don't recall if I ever knew that. that was good to know
what about millepedes?

 
At 00:47, Blogger Kathiesbirds said...

Doug, it's because of posts like this that I have nominated you for a "Blogs That Make My Day" award. Find the info here: http://coronadetucson.blogspot.com/2008/05/blogging-award-from-texas-travelers.html

 
At 09:40, Blogger robin andrea said...

That is the kind of information that makes me glad I started reading blogs. I had no idea.

 
At 13:51, Anonymous Mark H said...

I'm with Robin. NO idea. THANKS to the doctor once again! No fee for helping me learn more about the nature world I love?

 
At 18:24, Blogger rodger said...

I could use a few protrusions from my abdomen making it easier to make it back to the couch after playing with the dog on the floor.

I don't think I ever knew this either, thanks!

 
At 11:48, Blogger Homer said...

What insect has the most legs? And the least number?

 
At 11:54, Blogger Marvin said...

I have now learned something new today, so I reckon I can go back to bed.

Marvin @ Nature in the Ozarks

 
At 13:45, Blogger Doug Taron said...

First of all, thatks to everyone. As I was looking at the photo, it occurred to me that this might be a revelation to a bunch of folks.

tr- This is a sphinx moth caterpillar, but I don't know what species it is. It was on elm. I'll resist the temptation to go there on you rsecond question...

Spo- millipedes are not insects, but part of another group of arthropods. They don't really have 1000 legs. A few hundred is more typical. there is one species that gets close- 7 or 800 legs.

Kathie- Thank you kindly

Homer. The answer to all of your questions is 6. All insects have 6 legs, no more no less. Some of them have underdeveloped or vestigial legs, but even they total 6. The class name for insects is Hexapoda.

 
At 14:07, Blogger Homer said...

That was a trick question! Hah, I knew the entomologist would get it right.

 
At 10:26, Blogger Doug Taron said...

Homer- My first thought when I read it was "wait, is this a trick question?" I almost wrote that in my answer to you. I would have found it very surprising if you didn't know that

 
At 06:26, Blogger BentonQuest said...

Thanks, that was interesting! I guess I just thought the legs "fell off" or something. OR maybe there were different rules for the larval stage.

 
At 22:32, Blogger Doug Taron said...

Ben- When I was a kid I also thought that the 6 legs rule didn't count because it was a larva. I wonder if that's a common misconception.

 
At 09:17, Anonymous Mary said...

I think this is a clear winged sphinx moth catepillar. I found one eating a holly berry in my garden in northeast Ohio. I'm thrilled to have finally identified it.

 

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