I didn’t do anything in the garden today because it rained most of this afternoon and evening. I did have to run out in the rain to gather caterpillar food though. Now that I have nine Eastern Black Swallowtail caterpillars with another on the way, my few dill plants will not be enough to feed the voracious little things, so they’ll just have to suck it up and switch to carrot leaves. I did also find four more Monarch eggs yesterday. After the total butterfly drought last year, now it’s a butterfly glut. Feast or famine.
Here’s the Monarch caterpillar on Day 18. By now it’s chosen its spot to turn into a chrysalis and will spend some time preparing the site by spinning a network of silk to provide anchorage. After a while, it simply sits there. As with previous ecdysis events, the body contracts lengthwise; whereas it was about two inches long previously, now it’s about an inch and a half long. As of this picture, it’s approximately five hours into the process.
Six hours later, the caterpillar is hanging head down in the characteristic Monarch J-shape as it prepares for its final moult. At this point there’s no going back; if it feels threatened it will curl up as much as it can, but that’s it. It can’t crawl away or drop from a predator. Unlike other moults, the face and body come off in one whole piece. I’ve never been lucky enough to find one in the actual process of moult. This stage lasts…ten? twelve? hours. Something like that.
Just three or four hours after the last picture, the skin is a crumpled heap on the floor and this is the result. At this point the whole thing is slightly translucent, and the skin is still soft and a bit rumpled looking.
Roughly a day and a half later (Day 21), and the colours have since solidified and gone opaque. The muddy yellow stripes and smears have coalesced into gold dots and bands, and the whole thing is a lovely creamy green, like a droplet of Chinese jade. I sometimes wonder if that gold pigment could be isolated and analysed to synthesise a truly organic gold paint. The whole thing is only an inch long. That picture really doesn’t do it justice; you can easily find much better with a Web search.
Monarch pupation takes about a week and a half, so that’s it for Monarch pictures until then.
And here it is two days later, now about a centimetre and a half long. When it first hatched, it would have been barely as thick as the dill frond it rested on; now it can chew one down like a cartoon character shoving food into its mouth. EBS caterpillars have a slightly different feeding and activity cycle than Monarchs; the former will rest for a while after every section of leaf it eats, while the latter doesn’t stop nearly as often. Just in this picture, it’s displaying the typical EBS caterpillar feeding behaviour: it will anchor its hind section and ‘walk’ its front legs up a leaf to drag it down, then eat it from the tip. I think this way it needs to move around less, because most EBS host plants have divided or feathery leaves.
For no reason at all, I wanted to take a picture of the caterpillar’s face that fell off during ecdysis. Knowing that neither I nor my camera were really up to the task of macro-ing something that’s less than two millimetres across, I had the idea to use a magnifying glass. It’s nothing special…it kind of reminds me of a bandit mask or something. It’s a bit of a wasted photo.