Because, despite what the books say, monarchs get eaten by wasps, Melissa, at least here they do. As a matter of fact, they're a wasp favorite here. Several years ago I raised some monarchs by sleeving the milkweed - wasps had already eaten some little ones, and keeping A. curassavica fresh in water is difficult, so I tried sleeving. Frass had accumulated in the sleeve, so I untied it to empty it, and when I did, a wasp flew up into the sleeve and killed my monarch cat! I'll never forget this! I almost got stung myself.
I was so mad at the wasp I got a can of WD40 - the only thing I had nearby - and tried to spray it with it! I think I missed, 'can't remember, it's been a while.
There's a lot of misinformation out there!
Sherry

Yeah I've seen the wasps eating the monarchs myself. Probably other things get them too, I don't know. What I do know is that as many eggs as are left on my plants, I almost NEVER find any caterpillars that make it past the first few days. (And if they were living to maturity my plants would show it!) I have a story like Sherry's, where one day I came across a wasp devouring a baby caterpillar, and he was so intent on it I was able to snip him in half with my clippers before he even realized I was there. I am usually a live-and-let-live type (even for wasps) but that guy made me mad.

Wow, the wasps are relentless! It is a good thing so many people are raising Monarchs then. I was hoping that milkweed made them unpalatable to everything. I guess I will be heading out to get another butterfly habitat for the monarchs!

Thanks for the information!

Melissa

I've heard before that more than 90% of monarch eggs will not make it to the butterfly stage.

The eggs and cats are eaten by wasps, spiders, ants, and more...

Before the monarchs layed eggs this year, I saw wasps scouring the leaves searching for them.

Most of the monarch cats I have found so far have been on the tiniest plants where predators don't patrol.

If you take in monarch eggs/cats you are GREATLY increasing their chance of survival.

I raise Monarch cats because if I wouldn't, very few would live to adulthood. After the insects had them and there was nothing I could do to save them, I saw Monarch cats that were taken by spiders, soldier bugs, wasps, and robber flies. There are plenty of insects and spiders that are only too happy to make a meal out of Monarchs. Also, I've had Monarch cats that had been parasitized by those darn Tachinid flies when they found them before I brought them in to raise. The Monarch cat would almost be big enough to pupate or had already pupated and instead of ending up with a Monarch butterfly, I had fly pupae instead, which I destroyed.

The poisons that are taken in by the Monarchs by eating milkweed might make other creatures like birds ill, thus making them avoid them in the future, but as far as I know the poisons have no or little effect on invertebrates. Caterpillars being preyed upon (and parasitized) doesn't just apply to Monarchs but also other butterfly cats (which is why I don't limit my cat raising to just Monarchs). The very first year that I raised Black Swallowtail cats I apparently didn't collect the cats before a wasp found them. Out of the Black Swallowtail cats that overwintered that year, I had two that never made it. Instead of Black Swallowtail butterflies coming out of the chrysalis the next spring, I had two darn wasps instead. Some people might say it's the circle of life, but since I see way more wasps and flies than I do butterflies, I help the butterflies as much as I can.
Cathy

Dittos to the above. In the big picture, my view is that being a Monarch (or Black Swallowtail, or ...) should provide a Darwinian advantage. :) Some day I hope to be broad-minded enough to include moths in that set.

Sherry, I'm picturing a mad you grabbing a can of WD-40. Priceless!

Jeff

Not too many wasps in our yard, but we make up for it with many many ants. They patrol the milkweeds, looking for monarch eggs, and small caterpillars. It's a jungle out there!

Hehehe, you're right, Jeff - I'm sure I looked like Lucy Ricardo out there!

The only caterpillars I know of that can (usually) be left outside to raise themselves, unmolested by predators, are pipevine swallowtails. In years when I've been inundated with them, I've left some of them outside, and only once were they victims of predators - real big, metallic turquoise-colored stink bugs with red patches on their shoulders -
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I left a few of the present group I'm raising outside this year, but I brought them in today. They weren't growing as fast as the ones in the cages on my porch - I assume the heat was getting to them.
Sherry

I heard that Monarch caterpillars and butterflies are unpalatable to birds and mammals, but other insects are not affected by the glycosides. I once witnessed a very large dragon fly carry off a Monarch adult!

As I was searching the wild A. syriaca out back yesterday for Monarch cats, it turned into a kind of fascinating insect hunt. I would open up the growing tips of the milkweed, never sure what I would find. One plant would harbor a spider; another a bunch of ants crawling up and down the young leaves; some had milkweed beetles; and a couple had earwigs! Not surprisingly, no cats on those. However one plant had no sign of insects, but a little frass. Found a little 2nd instar on that one. :)

I raise Monarchs because it is very enjoyable and relaxing (and therapeutic when one is stressed or depressed), their life cycle is simply an amazing natural process, and of course, because it greatly increases the odds of an egg making it to adulthood.

I actually took a photograph of a praying mantis who was eating a monarch caterpillar in my garden last summer. I just happened to go out into my garden, just happened to look straight at the thing and actually "see" it right off, and just happend to have my camera in my hand. I was so upset. :-( If I could ever figure out how to post pictuers I'd share the picture here.

I've witnessed the wasps attacking my EBST cats, but never personally seen them eating or attacking a monarch cat, but they defitely "patrol" the butterfly weed plants in my garden.

~Laura

Same here. Wasps eat them.