Friday, April 1, 2011

unidentified caterpillar ~ 04/01/11 ~ at home


unidentified woollybear caterpillar
possible Hypercombe, Grammia, or Spilosoma sp.

I collected this one 03/31/11 down in the Carmel Highlands. Coincidentally I saw several others in La Selva Beach in Santa Cruz County on 04/02/11. I've hesitated posting these pics for several reasons, the least of which is I don't know what it is. Indeed, there are many species of all black, fuzzy, tiger moth caterpillars. The term "woollybear" can be generically applied to any fuzzy caterpillar in the Arctiini tribe. I suspect the most recognizable tiger moth caterpillar is the banded woollybear (Pyrrharctia isabella), which is more common in the eastern U.S. but can occasionally be found in CA. What I have is NOT an Isabella tiger moth.

The best way to identify an unknown caterpillar is to raise one and identify the adult. The challenge with this is figuring out what it eats, being patient enough to let it rest and pupate, and having the luck that it doesn't die in the process. I initially tried to feed it oak leaves, but this one didn't seem interested. I offered it some radish tops and it chomped away for a couple days. Then a week ago (I'm posting 04/09/11), I found it curled up on top of the soil in the container. Had it not been curled up I would have thought it was getting ready to pupate. I figured it must have died and was quite sad. By the next morning, it had climbed up the oak twigs. Since then, it's done this several times without eating any more, despite my throwing in a veritable salad of radish tops, lettuce, and dandelion shoots. It's been stormy off and on this past week, so I wonder if this playing dead and climbing is a natural behavior and/or related to the weather.

Finally, in an all black fuzzy caterpillar, I wanted to take a picture of the most distinguishable feature. In the first picture above, those 10 red things are prolegs. Without getting into too much repetition of what can easily be found elsewhere online or in books, lepidopteran larvae have 6 jointed legs and up to 10 prolegs. Caterpillar lookalikes have differing number of prolegs: some beetle larvae have 6 jointed legs and no prolegs; and sawflies (not flies, but wasps) have 6 jointed legs and 12 to 16 prolegs.

13 comments:

John @ Beans and I on the Loose said...

An enjoyable read this morning. Long ago when I was a little guy I read about fuzzy carepillars in a far away land that were poisonous to the touch. I invisioned some horrible type of death with your skin turning all mushy and green dripping off your body like syrup. I guess that scarred me for life. To this day whenever I see a caterpillar with fur, fuzz or decorative spines protruding from it's body I go "naaa..I best leave it alone."

Katie (Nature ID) said...

Can I call you JL? Apparently, you have always had a very active imagination. There are some caterpillars that can hurt to touch; this isn't one of them. Here's a link you might like: http://www.ca.uky.edu/entomology/entfacts/ef003.asp

James said...

I love these guys! I've seen a few out already this season, though I haven't keyed out what they were. A couple seasons back I was out in the local canyon where in one spot the ground was covered with dozens to hundreds of them. Everywhere. Wild.

Katie (Nature ID) said...

James, I've asked around to some lep experts and NO ONE knows what these are. I find that interesting since they do seem to be fairly common. This little caterpillar is getting fatter, even though I have yet to observe it feeding in several days. I'm keeping my fingers crossed that it'll survive to an adult moth for ID.

Anonymous said...

I live in San Carlos CA, and found a bunch of these today. Did you ever identify them? Thanks, David.

Katie (Nature ID) said...

Sorry, David, I was never able to successfully raise one to adult moth, so I don't know. I stand by my 3 possible genus guesses in the ID above. I spotted some of these caterpillars over the weekend as well, so maybe they're a little early this year.

Nornie said...

I have been finding many of these on my back porch over the last few weeks - always very lethargic. Today I found a lethargic black blocks with white moth? with orange areas, maybe an inch long. awhile later the white had turned to orange... it seemed alive but not moving. Just now I went to look and it's gone. I have a photo of it, can I post it?

Katie (Nature ID) said...

Wow, I really haven't paid much attention to this old blog. So sorry, Nornie, for the delay of almost 1 1/2 years! Not sure where you are or how to decipher your description. I do hope you're being kind to the caterpillars that cross your path.

Unknown said...

Giant Leopard Moth

Katie (Nature ID) said...

Dear Unknown - Great guess, but nope! I've known caterpillars from Ohio and California for years, having reared many of them, which tends to make me very familiar with what each eats and their habits. Mine do not have the red body underneath the fuzz, like the eastern US Hypercompe scribonia larvae. Hence why I chose to take pictures of prolegs. It's been unfortunate that I've not been able to successfully rear one of these local CA versions of woolly bear caterpillars to adulthood. I suspect ours need a lot of room to roam every day up and down, something I cannot provide in a captive setting. A friend found a pupa tucked away, with its cast exoskeleton attached (very identifying), and it came out as "nondescript mottled grayish color". Thanks for trying. - Kt

Anonymous said...

HI there,

My name is Bruno. I live in the south of Portugal and have found some caterpillar just like yours... Any luck with the indentification? It is so odd that nobody seems to know about this fairly common one...
Best wishes,
Bruno

Katie (Nature ID) said...

Hi Bruno - Yes, I have a good guess that mine are painted tiger moths (Arachnis picta), but it's supposedly only found in the southwestern part of the US: https://mothphotographersgroup.msstate.edu/species.php?hodges=8152. Given there are so many caterpillars like this, maybe you have one of the Arachnis relatives in Portugal? If you want to see what my local painted moths look like, check out: http://natureid.blogspot.com/2010/10/painted-tiger-moth-arachnis-picta-i.html. Hope this helps. -Katie

Anonymous said...

I touched a fuzzy one one time it was lime green and white and i broke out in hives all over the place i will never forget that…actually someone threw it on me but yea they are lol