Unusually small caterpillars

[Mom2RJA]

I have two caterpillars that hatched 5/15 that are growing very slowly. My other 5/15 cats and most of my 5/16 cats pupated today. These two look about a week younger. They are eating and appear to be totally normal and healthy but they are just small. They are not in the same container (both are isolated in their own jars). Any thoughts?

[Mona Miller]

They are sick or so just slow maturing. That's the neat thing about insects, they don't have all the same behaviors. A few of them, keep us guessing.

[Paul Cherubini]

As long as they are eating alot they should do fine.
Smaller caterpillars is a common consequence of feeding
milkweed cuttings instead of milkweed growing in soil
Also a consequence of rearing indoors vs outdoors.

[Mona Miller]

Paul,

I wish you'd slither back under your rock.

You didn't read what she said. The other caterpillars from the eggs she hatch grew fine and have pupated. These two are growing slowly and are small and are taking longer. As along as the cuttings are fresh, frass (butterfly poop) is cleaned out at least every day, there's not much difference in those raised on cuttings and potted plants.

[Mom2RJA]

Thanks, Mona. Yes, I am picking fresh leaves for them at least once every day and cleaning out the frass at least daily. All my other cats are big and fat. I hope these two start growing and turn out to be okay.

[Mona Miller]

What type of jar are you using? If glass remember to keep it away from direct sunlight. Glass absorbs heat and can fry its contents. Also, if available, you can sterilize the jars in the dishwasher. I use a pots and pans cycle and then a second rinse only.

http://www.raisingbutterflies.org/about-me/
Raising Butterflies by Todd Stout
http://www.raisingbutterflies.org/the-monarch/
Todd talks more about raising and finding Monarchs

http://dragonflypower.com/MSReference.htm
This is also a good video on raising butterflies. Scroll down a bit to see the index of the video. Please make a donation, if you can. I did. This video covers every thing. At the end there is a segment on a butterfly farmer.

[Mom2RJA]

I have some glass jars and some plastic. They are all on the buffet in my living room at the moment, never in direct sunlight. The whole buffet is covered with jars! I have never had so many caterpillars. I raised 17 butterflies last summer, and right now I have 46! It's getting a lot easier though, as about half of them have pupated in the last couple of days.

[Mona Miller]

That's a lot to feed. I also raise many other butterflies and moths. I raise and release them for conservation.

My dinning room table doesn't get used for anything other than raising butterflies in the late spring, summer, to fall. I also have a 10'x10' screen tent with butterfly larvae on host plants. My tent has Zebra and Pipevine Swallowtails.

[Mom2RJA]

My small ones are still small but still eating and growing slowly. I can't figure this out. They are now 20 days old. I keep expecting them to die or show signs of illness, but they don't. One of them has unusual markings though--wider black stripes than normal and virtually no white.

[Mona Miller]

Darker caterpillars could mean they are too cold. Where are you raising them? I hope not to close to an air conditioning vent or air conditioner.

They can also have genetic abnormalities that could cause this problem.

Hang in there, I always separate, keep feeding, hope for the best.

[Mom2RJA]

We don't run air conditioning, and they are not near a window or vent. All of our caterpillars are in glass or plastic jars on a buffet in our living room. This is the only one with these markings, so I'm pretty sure it's not temperature related. The other tiny 5/15 caterpillar isn't dark like that. It didn't turn dark like that until its last molt, so I'm not sure what that means. I'll just keep feeding and watching and hoping they'll be okay.

[Mona Miller]

If possible, can you post a picture?

[Mom2RJA]

This photo was three days ago. It is bigger now, but still has this coloring.

[Mona Miller]

http://www.mymonarchguide.com/2007/11/o ... llars.html
OE on Caterpillars

[Mom2RJA]

Ugh, I hope it isn't OE, but I guess that does seem likely. Is there any chance of recovery from this? Is it likely that the other slow-grower has OE too, even though it doesn't look dark like this one? I also have three chrysalises from eggs found the same day in the same place and hatched on the same day as these two, but the other three all grew and pupated totally normally. Are they probably okay? I have the two slow ones isolated, but the three chrysalises are with my other chrysalises and should emerge in the next few days. Do I need to be worried about them? These caterpillars may have shared a jar with them in the early days (before they stopped growing normally).

[Mona Miller]

I've had caterpillars raised from eggs where some ended up having OE and the others did not. Do you know how to test the butterflies for OE?

Just make sure you sterilize your jars good between broods.

[Mom2RJA]

No, I don't know how to test butterflies for OE. Should I be testing all of them? Until now, my knowledge of OE basically consisted of seeing on a map that it's not a problem here in Michigan. I guess maybe that has changed?

[Mona Miller]

http://www.uga.edu/monarchparasites/whatisOE/index.html
How to tell if butterflies are infected with OE
"An infected pupa may develop dark spots or blotches two or three days before the butterfly emerges. These abnormal dark areas are parasite spores. Spores form on the eyes, antennae, wing veins, but mostly on the abdomen. You can see the spores through the outside layer of the pupa a day or two before pigments that color the butterfly normally darken the pupa. Before a butterfly emerges from the chrysalis, pigments are laid down coloring the scales that cover the butterfly. This normal change in the color of the pupa is symmetrical. The color change of an infected monarch happens earlier and does not create a balanced pattern on the pupa.

What map are you looking at? OE is every where. This year our winters weren't as cold as they should have been. We didn't have much of a winter in my area; therefore, I'd bet OE will be more of a problem this year. OE usually gets killed off during winters where it freezes.

http://monarchparasites.uga.edu/monarch ... sults.html
Here are the results for OE. Check these out.

[Mom2RJA]

We did have a very mild winter here (although it did freeze). Is there any way to test a caterpillar for OE?

[Mona Miller]

There's no way to test a caterpillar other than the signs from the website that I posted. Sorry.

[Mom2RJA]

Thanks. I was wondering if the tape/microscope method worked with cats too.

If a butterfly tests positive for OE, I know it shouldn't be released because it could spread the spores. Is it possible to just keep it and feed it in captivity for as long as it lives? I would have a really hard time destroying a perfectly healthy looking butterfly.

[Mona Miller]

Actually a butterfly that has OE is not perfectly healthy. It is a carrier. Yes it is hard to kill them. I usually put them into a baggie and freeze them. It is far better to keep them from infecting other butterflies.

If you kept it and fed it, how would you keep it from infecting your home. That's the problem. Spores can last on surfaces for a very long time.

[Mom2RJA]

This butterfly emerged today. Her chrysalis was smaller than others and she is a small butterfly. I was worried that she would have trouble emerging or be deformed, but not only did she emerge just fine--she also escaped from the netting I put around the rack the chrysalis was on and flew around our living room by the time we got up this morning! My son named her Houdini! I bought a microscope and tested her, and there is NO sign of OE. Just butterfly scales like my other healthy butterflies. My son is really happy.

When this caterpillar took so long to grow and looked like she had OE, I felt like I should probably euthanize but I just couldn't bring myself to do it. I thought the same thing about the chrysalis that was small and not as brightly colored as others. But I am so glad I let her live. She is a healthy and very active butterfly. I would post a photo, but I'm not sure she'll hold still long enough to take one!

Relevant dates:

5/14: Egg found
5/15: Egg hatched
6/10: Chrysalis
6/20: Butterfly

Incidentally, my other caterpillar that hatched on 5/15 and grew slowly never showed any discoloration and looked perfectly normal, just small and slow to grow. That one died on 6/12 after producing some very light colored frass for a couple of days.

[Mona Miller]

I am so glad to hear that you had a happy ending to your small caterpillar and pupa.

I usually advise people to take a wait and see attitude. I've nursed many a caterpillar through a difficult process. Some of the stories end up with happy ending.

[califspaw]

I also had two cats that grew smaller than the rest and looked exactly like the one pictured, the white lines were very minimal. They ate the same amount as my other cats and were in the same room, we have had very warm days and cool nights here in Covina, Ca. Both turned into their chrysalis this Sunday I will see how they turn out in 10 days.

[Mona Miller]

The ones that made it from my spring group all pupated fine. I still haven't figure out what happened.

[califspaw]

One of my small cats. Came out of it's chrysalis yesterday, I just released it. She was a little bit smaller than some of the others that emerged. The second small one doesn't look ready yet, chrysalis is still green.