How to encourage the caterpillars to stay near the milkweed?

[aphid]

I mentioned in thread "Where do the caterpillars go?" that the caterpillars appeared to climb off the butterfly weed during the day and hide underneath other more broadleafed weeds. The butterfly weed I have was in it's first year, and I had started it from seed, so none of them got very tall. Each of the caterpillars ventured off to find something else (probably taller) when they went to form their chrysalis.

I have found one of the four in chrysalis form, and it did so using an evergreen shrub. Another, I found preparing to hang off a weed about a foot and half away from the butterfly weed patch, so it didn't venture far or any higher for that matter. Thinking it would get stepped on, I quickly moved it to a common milkweed across the yard, thinking it would have a better chance j-hooking there, which the plant was three feet tall at the time. It wandered off and I never did see it again.

The waystation program suggests to keep the milkweed weeded/mulched, if I remember correctly. Thinking of my experience so far this year, they seem to prefer some (non-milkweed) weeds around to hide in. I intend to keep all the milkweed mulched next year, so I'll see how it goes then. I am wondering what the rest of you think?

Also, if the caterpillars wander off in search of "better" place to j-hook... and the waystation program mentions "shelter" but doesn't really define what that means. I had the thought to maybe place some tall structures, in and around the various milkweeds next year. Something like a trellis in the form of a obelisk, and maybe have honeyvine milkweed climb it too. I would think this would provide an appealing vertical place for them to zero in on. My current setup, albeit my first attempt, each of the milkweed patches are small and surrounded by lawn. Discovering that the caterpillars wandered, I was afraid to mow too frequently, unless I could account for their whereabouts. Anybody have suggestions?

[freda]

I know this answer is a year or so late, but still worth a shot. I think trying to structure anything for these cats, either to ‘hide’ on or to pupate on, would be like trying to herd cats…real cats! It’s been my understanding from others’ posts that the caterpillars feed almost constantly and only leave the milkweed plants to shed their skin, then retrace their steps to the original milkweed…so don’t mess with their return path. At least that’s what I took from the messages. As for their choice of location to pupate…the first year we had them in our garden I tried positioning small boards, propped up on rocks, and placing other structures for them. Nope….they pupated on whatever caught their instinct at the moment. In some cases it was just from a broad blade of grass. They will move great distances to find the perfect (for them) leaf or branch to hang from. The grass around our milkweed patch has become very overgrown as a result of being wary of cutting it. I’ve spent the better part of a day watching two cats wandering, looking for their perfect spot. I watched them try out certain leaves and perhaps decided there wasn’t enough support so they moved on. In an enclosure (rearing indoors) they’ll often wander within an ice cream pail for some long while before pupating from the lid. Hope this helps…11 months later!

Freda

[aphid]

freda, thanks for the reply, it was helpful, here are some of my observations since then;

In every case, I've seen monarch caterpillar leave the milkweed to molt, and even seem to avoid any milkweed plant altogether when choosing a spot to J-hook on. I've also noticed of the larger caterpillars (and not just with monarchs), twitch when they feel a breeze... like they are trying to protect themselves somehow from flying insects.

The first year I had monarch caterpillars, they were on some first year butterfly weed (asclepias tuberosa) and would regularly leave the milkweed for the surrounding weeds and grass. At first I thought this meant they were quickly being eaten. Caterpillars that I hadn't seen in two days would reappear. Then I thought they wandered a couple feet from the milkweed when they did leave the milkweed. I've found that they don't tend to wander far, and it seems as though as long as they find a spot that is relatively shaded and feel secure, the distance is rarely more than 12 inches from a host plant, to which they probably always backtrack to the milkweed. From this I began being careful where I stepped when checking out the milkweed/caterpillars. Since I don't keep a very large buffer zone of mulched area around the milkweed, I tend not to mow the grass 6 inches from the planted area often, and only trim after confirming there aren't any hiding out. Not all of them would hide during the day, but at least they were usually underneath a milkweed leaf unless they were actively eating.

I have witnessed on multiple occasions: caterpillar finds non-milkweed foliage with in reach... takes the route... for whatever reason the return route is obstructed... the caterpillar can later be found wandering looking for any milkweed to continue feeding on.

If a wandering caterpillar looks to be a late instar, and you return it to milkweed: If it is looking for milkweed to eat, it will stay still for a short while, investigate it's location, wander a bit (usually upwards) then rest, content that it is at least on milkweed -- there is no guarantee it will remain there, though I think this has more to do with whether they approve of the milkweed they've been moved to; the health of the plant, or the type of milkweed. If it is looking for a molting place, it usually is curled up in your hand, generally refuses to grab onto the foliage of whatever plant you try to stick it on, investigates it's location, perturbed its on milkweed finds the nearest way off, often downward or laterally onto other foliage. Generally, the more you handle a caterpillar the more it plays dead, and the longer you'll have to wait to determine what its going to do.

Yesterday, I was wondering if maybe the caterpillars sense the warmth of sunlight and that gets them to seek some cover. Though I doubt it, since they'd all hide if that were the case.

Last year I started (8) tropical milkweed (asclepias curassavica) in a flower pot, which obviously didn't have any weeds/grass nearby for them to hide under. Only twice did I find caterpillars on the side of the flower pot.. and I don't think they were trying to hide, rather I think they were trying to move to another plant. The monarchs kept laying eggs on them and the first year swamp milkweeds (asclepias incarnata), that they kept defoliating the plants.

This year, the potted tropical milkweed (in its second year) haven't gotten any caterpillars. The swamp milkweed, the majority in their second year, have gotten 11 of the 13 caterpillars I've counted so far. I can say that on the upright ones, where the foliage doesn't touch any grass or weeds the caterpillars haven't moved off of the plant. However, I did notice twice where caterpillars had wandered off the tall plants and found there way to some of the first year swamp milkweeds. Of these two, one I think had been in the grass before I trimmed it, probably had to find another path back to the milkweed. The other I'm quite sure I saw hanging out low on a second year swamp milkweed and made the mistake of migrating downward after finishing off the leaf it was eating instead of upward where more foliage was. -- This was an interesting observation for me, because last year, on my bluevine milkweed (cynanchum laeve) if I saw a caterpillar low on the vine I could count on it being in the grass/weeds, as long as it hadn't been eaten. Instead if it was last seen high on a vine then it almost always was on the underside of a leaf, though on two occasions I found them on the underside of the fence the, which the vine was climbing.

I'll make seperate post of my conclusions.

[Mona Miller]

I think the Monarchs like to keep us (we are considered predators, too) and the rest of the predators guessing. If they had predictable patterns, then their predators would know exactly where to find them. If you are moving a pot, take care because I've seen them not only hang out on the inside of the edge of the pot, but also on the outside. I've also had them pupate on another pot in the same area. If the pot has an edge, I've found them tucked up under the edge out of the sun. In my tent, they loved the large garbage cans that I used to steady the tent corners. I put rocks in those and post them in each corner. The lid edge was covered with chrysalis.

[Pixie]

Over the course of this season, I have often found the cats off the milkweed & on other foliage in my gardens.......I have found them on the leaves of coneflowers, zinnias, asters, & on the ground. Some I have plucked off & put them back on the milkweeds & others I left to see what they would do - some do find their way back to the milkweed, but others I have found in the grass away from the garden - I just pick them up & put them back on the mlkweeds - I just think some of them are not too smart!!

[Mona Miller]

Some of them are avoiding predators during the day. I have a couple species of paper wasp that patrol the milkweed. Also, yellow jackets and those dang red eyed flies, too. I think that they leave the milkweed to molt and avoid predators.