Something different today. On my website I’ve posted that a sometime hobby of mine is raising monarch butterflies. This year I haven’t done it because several months ago I started seeing a lot of monarchs around and laying their eggs on my milkweed (asclepias), the only food the caterpillars eat. I figured I’d see how they fared without any help. Monarch caterpillars are voracious eaters. They can eat all the leaves off a medium-size milkweed plant in one or two days. So soon I had a lot of caterpillars and nothing for them to eat. I learned the hard way never to buy milkweed plants from a big box store like Lowe’s or Home Depot, because their plants have been sprayed and will kill the caterpillars. So I went to one of three nurseries where I’ve gotten plants in the past and have never had a problem with them. I bought four plants, brought them home, and transferred the caterpillars to them.
The caterpillars were in various stages of growth from very small to large and almost ready to pupate. And in only a short time I saw that they were all dying. The largest ones made it to the stage of forming their J, hanging from a stem or leaf in the form of a J just before they pupate; however, they didn’t succeed in forming a chrysalis. They tried, but before long they were dead. The plants had obviously been sprayed. I called the nursery from which I’d bought them, and was told that they never sprayed their plants. But, as happened to me once before when I had bought plants from what I thought was a reliable nursery, they had been sprayed by the supplier before shipment to the nursery. In that other case I took the plants in and got my money refunded, but in this case the owner assured me that I could just wash the plants and they’d be fine. That wouldn’t save the caterpillars, of course, but it would make them safe for a later crop.
Nope. Months later those plants are still toxic. I found that out when I spotted an egg on the leaf of a small plant that grew from a seed, so I knew it was safe. The egg hatched, I brought the plant inside to protect the little caterpillar from wasps that lay their eggs in the caterpillars and, when the eggs hatch, the larval wasps eat their way out of the caterpillar host, killing it. The little caterpillar grew and ate and soon had almost entirely defoliated that plant, so I took a chance and put it on one of the plants that had been sitting out where it was washed by my sprinklers and by all the rain we’ve had.
The caterpillar stopped eating and kept falling off the plant. I’d find it curled up in the dirt in the pot, think it was dead, pick it up, and have it uncurl and move around. I’d put it back on the plant, and first thing I knew, it would have fallen off again. I kept trying, but clearly, the plant was still toxic. I found another small plant that also grew from a seed, put the caterpillar on it, and no more falling off! It ate and grew and ate and grew, until the plant had no more leaves.
Again I put the caterpillar on one of the toxic plants. It didn’t fall off but it wouldn’t eat. I went yesterday morning to a nursery I had confidence in, got two plants, and put him on one of them. He ate a bit more and then formed his J on the edge of a leaf–not a good place. I was very afraid that all the trauma of being on those toxic plants would make him unable to pupate, or that if he did, in the process of forming the chrysalis the caterpillar moves and jerks all around, as he is literally turning inside out. This morning I came out and looked, and he had pupated! Apparently, I had just missed it, because the pupa wasn’t yet shaped properly. Or was it that he wasn’t able to form a proper pupa?
No, when I checked again about 20 minutes later, the pupa was well-formed, and it seems to be firmly attached to the leaf-edge. Now comes the wait to see whether he will emerge as a butterfly. I’m still concerned, but so far he’s overcome all the obstacles and I’m rooting for him.
Why all the trouble for a single caterpillar? Because we need the monarch butterflies and because it’s such an inspiration to see a caterpillar transform into such a beautiful creature.
Oh, and I have another small caterpillar just hatched day before yesterday and also now residing happily on one of the new plants.