Overnight, the majority of the caterpillars changed their skins. They spin a pad of silk, and then hook their rear feet in the silk; then they wiggle and shimmy their way out of the old skin. This is an old skin. You can see the rear feet at the top left, and you can see some of the hairs from the old skin in the middle of the shot. Click on the picture for the bigger version.
Here, you can see a first-instar caterpillar (left) who’s a day or so behind the game. The difference in size between the first instar and second instar head casings is substantial.
When they come out of the day of rest with new skins, they have a voracious appetite; they turn the mulberry leaves into lace.
It’s hard to get the focus just right to see it, but the head casings are surprisingly hairy.
After five days, the silkworms have grown SO much! Their heads are the same size as they were before, but now the heads look tiny on their thick bodies. The bodies look like they’re over-stuffed – like too much sausage stuffed into not enough casing.
At this scale, the head is about the same size as the other one. See how much it’s grown?
This one looks like it’s getting ready to shed its skin. This process involves a day of rest, followed by shedding the face mask and the full skin for a larger, looser one.
This is a male Polyphemus moth. I’m always fascinated by the variety of scales and textures on their wings, and I got some close-up photos so you can really see why butterflies and moths are called “Lepidoptera” meaning “Scaled wings”
The scales are formed of chitin, like the exoskeleton and the substrate of the wing, and they provide insulation, aerodynamic effect, and coloration. The colors can help a moth hide, or help it protect itself.
The thick, furry scales on the moth’s body not only help it retain heat (produced by the muscles – they can actually fly at quite low temperatures, and the body is hot to the touch after flight) but they also help make the moth harder to bite – the scales come off, and you might just get a mouth full of fuzz.
The gray fur on the head reminds me of salt and pepper hair.
These eyespots mimic the eyes of a predator. The moth will often rest with its wings folded, so that the spots are concealed – and then pop them out if threatened. This mimicing of a predator (particularly a predator common to the prey species and its predator species) is common in the animal world, and is called Batesian mimicry. I’ve gotten to observe it in Polyphemus moths first hand. After they are done breeding, I often feed spent moths to our backyard chickens. One female proved that she wasn’t quite done for, when the chickens ran up to claim their tasty snack – she popped out those big black eyes, and the chickens literally backed… away… slowly. It was cool, and kind of creepy.
Here you can see the texture of the individual scales. If you click on the picture, it takes you to the full-size image, where you can see it REALLY close up. The shiny spot is wing with no scales at all – it reflects light, and light passes through it, like glass.
The legs have another kind of hair-like scale. The big, muscular thighs and knees remind me of tarantula legs.
Because Jeoffry is a male moth, he has huge, plumose (feathery) antennae. The males use these to detect pheromones, or sex hormones, released into the air by the female. They can fly miles to find a female, tacking into the breeze to follow the trace of scent.
Here, in really-really-close zoom, you can see the individual little hair-like scales on the antennae; these have scent receptors which will comb through the night air and allow Jeoffry to smell his potential mate.
They hatched out just a couple of days ago, but they’re already noticeably larger. They will grow until their skins can’t expand any further, and then shed. On the bottom right corner, you can see the silk strands that they lay down constantly – these function as a safety line, if one of them falls off a branch.
These silkworm eggs are starting to turn “blue” – the developing worm inside separates from the shell, and they get a hazy lighter color. About half the eggs in this photo are blue – the others are likely nonviable.
If you look really close, and you’ve got a good magnification on your camera or hand lens, you can see the caterpillar curled inside the egg.
These have reached the head pigmentation stage; you can see the little dark heads. They’ll hatch within another day or two.
The Calleta caterpillars (Eupackardia calleta) started hatching today. These beautiful moths are native to much of the American southwest. I am raising them mostly for the fun of it – they do produce silk, but it’s not one I’ve made into yarn yet.
This tiny hatchling is eating cenizo – Leucophyllum frutescens – which many of my gardening friends call purple sage. Not related to the Salvia sages at all.
The caterpillars are covered with tiny bristles called scoli; these aren’t spiky to the touch for a person, but they would be get in the way if you were, say, a spider trying to put the bite on a caterpillar.
The insides of the hatched eggshells are beautiful – like rosy opals. The colors remind me of Maxfield Parrish.
Every year it happens… the leaves pop out on the local mulberry trees, and then it’s time to start the silkworms.
The Ancient Wisdom version says that you should start the silkworm eggs when the leaves are the size of a mouse’s ear. We don’t have the kind of long, slow spring where that lasts for long – so by the time I get a chance to snap a picture, they’re almost the size of a dime. This is a feral white mulberry tree in my yard in south Dallas.
These are the eggs. You can tell from the size of the fibers in the torn paper towel edges, these are pretty tiny. They’re about the size of poppy seeds.
When you get really, really close up, you can see the texture of the egg shell. The forming caterpillar embryos inside are in a state of rest called diapause; it allows them to survive through winter temperatures without dying, and they begin to metabolize and develop once they warm up in the spring.
I’ve enjoyed nature all my life. I was that kid, tromping in the woods, turning over logs to marvel at the life beneath, watching the patterns of light and shadow on leaves to see the hidden snake. Getting a camera with a good macro, and learning to take close-up shots, has taught me to look even closer – now, even without the camera, I see all kinds of neat things happening that I never even knew were there. Evolution is amazing, and the diversity of life is profound and humbling.
This house has been a revelation as well – our yard backs up to a wooded creek, and we garden organically, so there’s an abundance of life that I think would be missing in a lot of city dwellings. I’ve seen things here that I had previously only heard of, and many that I never even knew existed. We’ve got mantis flies, and tortoise beetles, and cuckoo wasps, and thread snakes. I’ve found several things where I’ve looked them up and read “Not much is known about their diet or habits” and just had to smile and shake my head at the amazing depth and complexity of life.
I found this cool tiny critter one night, luring moths to a sheet with a black light to see what would show up. It’s called Petrophila jaliscalis, less than half an inch long, and my eye was caught by the beautiful spangles on its rear wings. I couldn’t find anything like it, searching on the web. I put a request on Bugguide.net (an amazing resource, if you’re trying to ID something weird) and they pinned it down. This odd genus lives as caterpillars on stones in running water – creeks, streams, rivers.
What I didn’t find out until a lot more recently – there’s a very cool reason for the spangles on its wings. This whole genus mimics jumping spiders to help scare off predators. I found a jumping spider in the kitchen one afternoon, and got the macro lens and the ring light and shot some pictures. I’m still working on getting a firm ID for this spider, asking some smart folks on a Facebook spiders group; so far, it’s looking like Maevia inclemens.
Keep in mind, this whole spider is about the size of a pencil eraser – but with a macro lens, you can see it in magnifying-glass detail.
Here, it’s on the border where the white trim meets the yellow-painted wall… you get a sense of scale from the bubbles in the paint.
and then you adjust the lighting, and you shoot, and you shoot, and you find where the damned thing ran around the corner of the wall, and you move, and you shoot some more, and then you crop, and you adjust… and you get the portrait. I’m not a trained photographer, and I know there’s a lot that I could have done better – but I’m proud of this one.
It wasn’t until I saw an article about a spider-mimicry in metalmark moths, that I thought, “Hmm… those metallic marks look like the ones I saw on the little guy on the sheet!” and started looking into it.
And it all came together. I still want to get a better angled shot, so you can really see the “eye” and “leg” markings in the same positions. If you squint your eyes at the moth, you can definitely see the spider – and if you were some hungry bug, you might think twice. This is one of a dozen or more examples of Batesian mimicry I’ve seen in the yard; we’ve got ant-spiders, and bee-flies, and so many scary eyes.
Another cool link, showing the amazing underwater caterpillar in its *SILKEN CASE* (see, you knew there was going to be silk involved) –
I spent some time in the yard today with my Canon Rebel T2i. I love the convenience of having a camera in my phone, but it just doesn’t have the glass… with a 60mm macro lens, I can get a lot more detail, and catch more interesting things.
Another flower on the same vine. The three bees were wrestling all over one another in a pile, and it seemed really odd – they usually do that for pollen, but not so much nectar in the passionflowers. Then, when I was looking at the images in the camera, I realized that they have RIPPED OFF the pollen anthers, and are working them over in the middle of the flower. They remind me of Macbeth’s witches around their cauldron.
This exceptionally handsome Viceroy butterfly, Limenitis archippus, has set up a territory which includes the fig tree, the Maximilian sunflowers, and part of the creekside brush. He will aggressively chase any of the Fritilaries or other butterflies that come close, and sometimes he even buzzes the wasps. He’s a little petty tyrant.
I just wish they were as fragrant as their cousins – Cestrum nocturnum is my favorite fragrant flower in the world; I keep a bush in a pot, and bring it in to the bedroom when it’s in flower. It only flowers at night. This one has pretty flowers all day long – but no smell at all.