butterfly caterpillars

Susan W · Mon Jul 21, 2014 9:42 am

I came across one mid sized swallowtail butterfly caterpillar on some parsley while picking. I moved it on the stalk it was noching to the 'b + b' I've set for them (a couple small pots of parsley). I checked a couple times, noching away. Then poof! gone! It wasn't big enough to go to next stage. A couple days ago noticed another on a rue start on the deck. Now, with several large pots of parsley, how mom found the small rue start, whatever! (and there are a couple of larger rue plants elsewhere) I thought about moving it to larger plant, and figured to wait until g-son (5) came over. Yesterday showed it to son here. Later went to show it to LilDan. Poof! Gone! Not a sign anywhere, and not big enough for next stage. His 5 yr old comment was 'Grandma, it turned into a butterfly!'

Mystery is different plants, different areas. Something, perhaps feathered, must find these tasty.

rainbowgardener · Mon Jul 21, 2014 11:01 am

Yes, the mortality rate from birds is quite high. If you really want them to survive, you need to put them under netting or something, but then of course after they have pupated, you have to watch really closely for when they eclose (emerge as a butterfly) to let the butterfly out.

rainbowgardener · Tue Jul 22, 2014 12:47 am

I was leaving for work today and spotted one on a tall dill plant, very exposed and out in the open. I didn't have much time, but I broke off the top of the plant and moved it to ground level, caterpillar and all, put it in an area next to the dill plant but covered by other leaves, so at least it would be harder for the birds to spot.

Susan W · Tue Jul 22, 2014 4:34 pm

I am thinking I have feathered guests lurking. I've noticed the wrens getting up in the pots and figured they are keeping them clean. That can be good, but not so great for the swallowtail caterpillars! Hopefully the next one I come across I can move with small pot to a pop-up laundry hamper.

rainbowgardener · Wed Jul 23, 2014 7:05 am

So I looked at the same dill plant today and up at the (new) top, it had FOUR swallowtail caterpillars. One was probably the same one I "rescued" earlier, having climbed back up. It looked full sized and like it might be getting ready to pupate (had that kind of hooked on look at the top). The others were small, smaller, and teeny. In the interest of saving them, I took the whole top of the plant off with all four of them on it and put it down at ground level, protected by leaves. Do they like sunshine, is that why they keep crawling up to the top? The plant is more than 3 feet tall.

And I thought the range of sizes was odd. If they all hatched out from a clutch of eggs Ms. Swallowtail laid, wouldn't they all be approximately the same size?

applestar · Wed Jul 23, 2014 10:45 am

I think they like the more tender new shoots and floral buds. The oldest, ready to make chrysalis will seek a location with sufficient wing room to spread and dry after eclosing.

Sometimes caterpillars will go off somewhere less open to molt into next size instar caterpillar because they will be immobile for 12-24 hrs and they will be vulnerable. Mobile caterpillars will at least curl and jump off when threatened (smallest ones will bungee with a safety thread), but before, while and just after molting, the most they can do is wiggle in protest.

The different sizes could be different females laying eggs on different days. Unlike many pest moths, butterflies tend to spread their eggs around, so one butterfly would lay a couple of eggs on one plant, fly to another plant, and so on. Later in the season when they feel the fall approaching and start feeling desperate, they do start egg dumping, laying as many eggs as they can on each plant they can find.

rainbowgardener · Thu Jul 24, 2014 9:39 am

So your theory about different butterflies laying the eggs is confirmed, applestar! The dill plant on my deck (not the one I was talking about before) now has two swallowtail caterpillars on it, but they might be different ones. Both have the black stripes, but one is much yellower and one is much more greenish. Black swallowtail for sure, and possibly the anise swallowtail?

Usually it is my parsley that attracts them, that is why I grow so much of it, but this year they are liking the tall dill plants.

PS it did occur to me to wonder, the different caterpillars looked very much alike except the yellow vs lime green tone. I looked at pics and saw pics that looked like each of them, but they were all labeled as black swallowtail. Might it have somewhat different colors through different instars? These were also different sizes.