I'm so sorry for your loss, and especially being a newbie makes it harder I think. Something very well could have gotten the Swallowtail, but the Monarchs don't taste good to predators, and they can travel pretty far. Why don't you bring them inside like so many of us do to protect them? It's really easy, and there is plenty of help on this forum. I'm sure others will have more to say. I don't know about the black eggs.

Wasps will eat any caterpillar that they can get to. The Monarchs taste just fine to them.
-Jmcat

Are you watering your milkweed in the evening? This could be causing a potential for mold/mildews to grow because the leaves do not have enough air to sufficiently dry out and this could also lead to, potentially, a good environment for bacteria/viruses as well. I am just trying to think of all the things that I did as a novice (I still think of myself as a novice but learn from my mistakes). I added some stuff on my blog recently about this. You may want to check it out.

Hang in there. :)

Here is a link that might be useful: tdogmom's Monarch blog

How big were the caterpillars that disappeared? Were they big enough to make a chrysalis?

Caterpillars can go FAR FAR AWAY to make their chrysalis. I find caterpillars crawling 50-75 feet away from their host plants lots of times.

It is possible that they just got big enough to make their chrysalis and wandered off.

Thanks to everyone for your replies. Thanks for the tip about watering. I generally water in the late aafternoon/early evening. It's still pretty hot here in NJ though. But I guess I'll have to start doing it in the morning.

Of course I like the theory that they are both hiding somewhere happily becoming butterflies! I do believe they were both large enough to be about to enter that state.

Here's a pic of the big guy a couple of days before he went AWOL. I named him percival!

{{gwi:537585}}

Thanks,
Laurie

Lolly318 - I'm in northeastern NC and started my butterfly garden this year as well. Last week, I decided to check my parsley plants and found 12 cats on one plant. The other parsley plant was a little wilted so I gave it some water to revive it. The next day, there were eggs on the second plant. I am running out of parsley for these hungry guys. I now have 8 cats remaining and I have brought them inside and feeding them fresh parsley from the grocery store (I know - I just read that you shouldn't do this but there is nothing left on the parsley plant for them to eat!). Next year, we will start parsley from seed to have enough plants. I brought them inside yesterday and have them in an aquarium type container. Tonight I have to transfer them to another container so I can clean the container they are in now. They poop a lot. I hope to hear from you more since I am new at butterfly gardening as well. I'm pretty sure that my cats are black swallowtails. I plan on planting milkweed next year to attract Monarchs. This year was just an experiment for me. Talk to you soon.

Kathy

Well, the cat looks about the right size to pupate, so if you didn't find a corpse ... hope for the best!

Thank you elaineoz for letting me know they can "go away" to make the chrysalis. I was expecting the whole process to take place on my milkweed. I am so new to butterfly gardening and just discovered 3 cats on my milkweed today. My first ever! Thanks to mssherry I now know that they are monarchs. Anyway, I have got a lot of learning to do!

Wow this butterfly business is tricky! I found another monarch cat on my milkweed yesterday. It was already quite large. I've been checking the plant everyday since my first ones went missing. I don't know how I can go from no cats to one this big. Where was it hiding? Well, I go out this morning and there's another big cat (4th instar?) on the weed! Well where was he hiding? And then a small one (2nd instar?). So that's three. I am very excited but just perplexed. Are they coming from somewhere else? Are they that good at hiding? NOW tonight I go and check on them and there's only ONE big guy left.

Where do they go? I don't believe my yard is full of predators. Not too many bird or wasps that I'm aware of. I can't wait to wake up in the morning and see what I find. Any clue as to where they go to pupate if they don't pupate on the milkweed?