There is a Milkweed Beetle that eats the leaves, but they generally start at the edge and eat older leaves. Early cats will first sever several veins and then eat in the shape of a C on younger foliage. Older cats will sever the midrib and feed on the end. #5s will sever half the petiole or stem and feed on the dangling leaf, or on the growing tip. In all cases, the cat will cut off the flow of sap, making the MW a little less toxic.

There are 3 beetles that eat milkweed that I know of, here in Madison. One is shaped like a ladybug, but larger, with orange/black color. The second is more long and narrow, all orange, with black antennae that look a bit like a Texas longhorn cow. The third is also black and orange, with a more geometric color scheme, and a faceted body shape.

They will generally be on the underside of the leaf, to stay out of the sun and predators. Use a small hand mirror to check the undersides without disturbing them. In my garden I have some wild milkweed (A syriaca) I dug up off the side of the road, and it gets 101 times the cats as all my other fancy store bought milkweeds combined.

Happy Hunting and good luck in raising cats!

Check also the flower buds for eggs and larvae.
Spaceman, I believe the third insect you describe is a Milkweed Bug (not a beetle). They don't leave a chew pattern, but instead suck the sap thru a long, strawlike beak. They usually form family units toward the growing tips and flowers and overwinter as adults.

Thanks for the responses. I hope to find as many eggs and cats as I can. The milkweed in my yard is coming back strong and has multiplied. I've also got a few milkweed seedlings from winter sowing, and a few volunteers in the soil that was transplanted with my other native plants. These, along with the field of Syriaca, should give me plenty of resources for raising a bunch of Monarchs.

That sounds great! Just a warning, however, in case...some vacant lots are mowed periodically or if they get too "weedy". Some towns or HOA's require such mowing. It may not happen, but just know this in case it does. I've seen it happen.

Linda,
Thanks for the warning. It doesn't look as if this spot has been mowed for at least several years, based on the size of the saplings. The part along the road probably does got trimmed, but the largest part doesn't look touched. This neighborhood isn't high class, and the road is pretty rural, without sidewalks or curbs. I doubt anyone is complaining about an unmown lot. I'll let you know if it gets cut down. Fortunately, I have quite a bit of milkweed growing in my garden. So, I'll have something to feed any cats I find.

Martha

That's great you have a "milkweed field" nearby, Martha. Hope you find lots of eggs there!

I've been scouting the wild A syriaca in for the past few years. My favorite milkweed field is about 1 mile away. I hike down there regularly to collect eggs and leaves during peak Monarch raising season. It's a lovely walk and a beautiful field and the Monarchs love it. I'm going to scout for eggs earlier this year.