Has anyone ever come across this?

[dzyg]

I just found this forum and I was wondering if anyone ever witnessed this before. When I was changing the milkweed leaves and cleaning out one of my caterpillar jars I was shocked to see a 5 day old cat with a 1 day old cat in its jaws shaking it from side to side. I got it to let go but of course the little one died. I have never witnessed this before and even though I normally only put one cat in a jar, I have had two on several occassions. I was mortified. Is this normal for them to do that? Normally if I have more than one in a jar they are very close in age however I was running out of jars and put a large one it the one I had the tiny one in and so I put the tiny one in a jar with two 4 day old cats the day before this happened. Guess I won't be putting little ones in with larger ones any more, not that a 5 day old cat is large as it isn't but it was alot larger than the little one.

Another question I am curious about. Normally I only take in a few caterpillars each year to watch turn into butterflies. This year however I was on a rescue mission collecting eggs and caterpillars on plants that were to be mowed down so I have more than normal this year. But it got me to wondering since the above caterpillar is my first to die, are they more likely to survive by me taking them in or by me leaving them alone on a plant that I know is safe outside? I have lots of milkweeds in my side flowerbeds and there are more throughout our property. I saw a site that said only 10% of eggs laid make it to become a butterfly. I could take more in but if I think they are safe on the milkweeds they are on should I just leave them alone? The little guy above I guess was destined to die as if I wouldn't of taken the egg in, it would of gotten mowed over but I feel so guilty that it died cause I put it in a jar with a bigger caterpillar. What do you all think?

Thanks!

[John Beaulieu]

We have about 50 caterpillars in a cage (large aquarium with screened top) and they don't bother each other, but they are all the same size. Perhaps it is a different story when the sizes vary? They are all starting to J-hook now so the need to find fresh milkweed everyday is slowing down. This is the first year that we have caught the happy hookers actually splitting and dropping the caterpillar skin. Quite a sight to see the contortions that they go through.

[dzyg]

Thanks for your reply John. I did end up finding down in the messages here that Monarchs will eat or try to eat whatever gets in their way so apparently what happened was normal, sad to say. I will now only put caterpillars together if they are only a day or so apart in age. I also for the first time this year witnessed the transformation from the J hanging caterpillar to the crysallis. What an awesome experience! I took pics too while it was changing. All the other times I have just missed this happening but last Sat I sat in front of the cat hanging until I saw it, took four hours before it started but I was not missing that one. LOL! I have seen many butterlfies emerge from the crysallis but not forming in until now. Right now I have four crysallis and seven caterpillars. One cat should be hanging later tonight and form the crysallis in the morning. I have released two butterflies so far this summer, one male and one female. I keep one or two caterpillars in a 64oz plastic peanut butter jar, with hole drilled in the cover. I find it much easier to clean these out vs a larger container with more caterpillars. I clean and refresh the leaves once or twice a day.

In your case, 50 butterflies emerging around the same time must be awesome!

[Pat]

Ours don't bother each other either; haven't seen a big one eat a little one before. But when I find a new bunch of eggs, I always start them in a fresh container, so I don't have the smallest sizes mixed together much with anything bigger.

[ohiomonarchmama]

In repy to dzyg's second question:
I had wondered the same thing about predators and leaving eggs/cats on the milkweed vs. bringing them in to raise. I have seen many ants crawling on my milkweed this year and I am pretty sure they (or something else) are feasting on the eggs. I tore the end off a few of the leaves that I knew had eggs on them to "mark" them, and when I went back to check, the eggs were gone. I then decided they had a better chance in containers on my screened porch. Since I knew the eggs wouldn't "escape", I had left one of the containers uncovered and in the AM found no eggs and 2 earwigs hiding under the leaves. So beware! Other than that sad experience, I've released 10 butterflies (mostly males!), have 5 cats and 7 chrysalids to date. My biggest year so far. I made my own butterfly garden so I have fresh milkweed everyday instead of searching fields and roadsides, which drove my family nuts! On a few occasions, I have actually seen the females laying eggs, but as soon as August came, haven't seen many. Of course it doesn't help I keep releasing males! Also, I usually release them the day after they hatch so there is plenty of time for their wings to dry (and they don't really need food until day 2 as I read elsewhere)...I usually put in a sprig of buddleia for nectar just in case. Good luck! (PS, I also have had to put 2 or 3 cats per container, but have been careful to be sure they are the same size since your post- thanks for the info). Julie

[MILW]

Yes, I've caught earwigs patrolling my milkweed plants at night (infrared surveillance camera!). Nearly all eggs that I left on the plants either disappeared or were sucked dry... it might be the ants too. Anyway, now I've started bringing every egg I find inside for rearing.
-Scott

[Teresa]

I have a few cats that don't look "real" healthy because they are thin and long. Some have a small black slash on their backs. Is this from the bigger cats?

[Pamela Moresby]

Sometimes I've seen some caterpillars snap at each other while they are eating as they are competing for food. If it gets bad I separate them. I've never seen one eat another.

Pam

[Megathymus ursus]

All caterpillars are capable of cannibalism in the right circumstances. Don't overcrowd your larvae and do not keep little ones with larger ones.