Spare parts

Hermit crab enjoying his lunch.

Shrimp pellets; Yum!

Hermit crabs, besides the chelipeds (pincers) that they use to grab and carry things, have three pairs of mouthparts, which they use to hold and manipulate their food. Here, two are plainly visible as the hermit holds onto his fresh shrimp pellet.

He seems to have lost at least one of his chelipeds, probably after an argument with a crab, or even another hermit. He'll do fine, though; hermits can use the legs to grab their food, too. They're not as efficient, but they'll do. And with the next molt, he'll have a new cheliped. The blue appendage on the left is the growing replacement; hermit blood is blue, and the skin on the new pincer is still thin.

Blue blood and duplicate legs

Hermit crabs are peaceable critters. They are content, mostly, to trundle about, picking at bits of algae or scraps of yesterday's lunch. They don't mind carrying several of their friends on their backs; they take turns trying on interesting shells; they tidy up their neighbour's shells for them.

But - there's always a but - they have no patience when it comes to special treats. The first one they find is the one they absolutely must have. Even if someone else found it first.

So, Hermie A (we'll call her Eve) finds a yummy shrimp pellet and grabs it. Hermit B (Bob) comes along, sees the pellet, and tries to take it away. Eve retreats into her shell, taking the pellet with her. Bob grabs that shell and pokes away with his smaller pincer, trying to get the food. Eve shrinks back even farther, holds on tighter. Bob pokes and yanks. Usually, he gives up after a while, and Eve comes out still holding her dinner.

Sometimes things get out of hand, and Eve loses a leg. Better that than losing her food, she says. Legs grow back; treats don't.

An Eve was standing by the wall this evening, showing off her brand new leg.

The new leg is a rich blue.

As the leg grows, it will develop the nodules and hairs of a mature leg, but for now, the skin is smooth and transparent; the blue colour showing through is the hermit's blood. Our blood contains iron, which binds oxygen and carries it to our cells. It gives our hemoglobin a nice red colour. Crabs, including the hermits,* have hemocyanin instead; the oxygen-binding metal is copper, which turns the blood blue.

*So do some spiders, such as the tarantula.

Three arms and a half.

A month ago, the 25th of May, I brought home a three-armed starfish and posted his photo here.

3/5 of a star, an inch eye to eye. (The eyes are on the tips of the arms.)

I kept him in a hospital bowl for a week, and he seemed to be doing well, so I transferred him to the tank, where he went into hiding under a shell for another week. Now, he's out most days, eating barnacles and growing a leg.

And just look at him now! Fat and happy, and a little more balanced. An inch and a half eye to eye.

I don't see any buds for a fifth arm. I wonder if he's going to stop at four, or will start on the fifth when #4 is full size.

Valiant Valentine

I rescued a badly wounded anemone on the beach in Campbell River this August. (You may remember; the first post is here: and the second, once I'd established it at home.)

It was in poor shape; half cut through, with a quarter of its tentacles gone, and the mouth demolished. Still, it was alive and responding, and it handled the trip home ok. It settled down on the floor of the aquarium and set about healing. Very slowly. At first, s/he* didn't seem to be eating; after all, with the mouth torn up, how could s/he? I mashed crab pellets in water and fed hir* the paste every couple of days. Some of it washed away, but I could see movement in the mouth area; an attempt at swallowing at least.

And the tentacles slowly grew back, the mouth gradually opened up.

S/he's healed now, and actively feeding. Tonight, I watched hir grab a piece of fish that floated by, and pull it in with one tentacle. The mouth gaped open; the fish disappeared.

"Val"**, as I'm calling hir, is getting fat.

Burrowing anemone feeding. The tentacles curved inward just brought in another fish flake.

When I found hir on the beach, s/he was a blob of flesh about 2 cm. across the widest part, including column and disc and tentacles all mushed together. I measured hir tonight. The portion of the column above the sand is about 2 cm. tall, and wider than it is tall. When s/he's feeding, it swells up even more; the 2 cm. was after it shrunk away from my ruler. And there's another centimetre of sand underneath before it reaches the oyster shell where it is anchored.

The tentacles average another 1 1/2 cm., and opened up, they measure 4 cm. across, but can stretch even more to grab an interesting bit of food.

There's still a bit of white scar tissue on one side of the mouth, and the new tentacles on the left are shorter than the others. But they're catching up quickly.

I wonder how big s/he will get? A description from the University of Oregon gives a mature size of 2 1/2 cm. across the crown, about 2 times the length of the tentacles, and a column height of up to 6 cm. So now s/he's about full width, but can grow taller if s/he's happy in my tank.


* Hir and s/he: gender-neutral pronouns. (See Wikipedia.) Because I don't know whether s/he's male or female.

**The name comes from Valentine, for the heart marks on the tentacles, and also for Valiant, which s/he certainly is!

Home!

We're home again, exhausted, sunburnt, broke, mosquito-bitten, and lugging suitcases packed with dirty laundry, but having forgotten my big thermos of hot coffee in the motel; all the evidences of a great vacation. We must do it again next summer.

It's time we were home, though. Life here has been going on without us too long. A spider has set up shop in the bathroom, the raccoons have been pawing through my garden. and slugs have eaten Laurie's swiss chard. And an unidentified cocoon has opened in our absence to release a beautiful moth. I'll take photos tomorrow, in daylight.

It's good to be home!

Sunset, Oyster Bay

Update: I forgot to add this. The damaged anemone has been recovering, regenerating the lost half of its mouth and tentacles. It came home with us, and survived the trip beautifully. More on this later.

Recovery, Part three

One advantage to having many mouthparts, like a crab does, is that they can substitute for hands. So when my poisoned shore crab lost both of his pincers, he didn't have to go on a diet, just because he couldn't pick up his food. Instead, he bent down to the ground to grab things with two big, flat paddles, the third maxillipeds. The second maxillipeds (read "jaw feet") have hooks on the ends; between hooks and paddles, he could cut and tear a salad of sea lettuce, or mash a fish filet. And he still had lots of machinery behind those, for chewing; another pair of maxillipeds, two pair of maxillae (jaws), and a pair of mandibles. No problem.

It did worry me when he molted, and promptly lost his replacement pincers and a pair of legs, too. This is a fairly common reaction to stress, called autotomy; the crab amputates his own limbs, usually just one of the pincers. Two pincers and two legs was a sign that Mr. Crab was at the end of his resources.

Once the tank was completely cleaned out, he seemed happy enough. He didn't lose any more pieces. I made sure to feed him well, putting treats down right in front of him, and turning off the water pump until he'd finished eating.

That was in July. In August, I noticed a tiny bud where one pincer had broken off. He had started the process of regeneration. In mid-September, two pincers were well on their way.

Six-legged crab, with pincer buds. Inside the translucent covering, the developing claws are visible.

Yesterday morning, he molted again. And now he has two pincers, and all eight legs.

The pincers are smaller than the originals that he lost. Next molt should fix that.

The molted shell, showing the buds where the pincers grew.

When he backed out of his old shell, his skin was soft and pliable. He pumped his body full of water to expand the tissues before the shell hardened, leaving him room to grow. The new pincers expanded like balloons, so they are many times the size of the buds they came out of.

The tank looks healthy now; the amphipods are multiplying again, and three tiny hairy hermits are scrambling about happily. I think Mr. Crab will be able to keep those shiny, new pincers this time. It's been almost 48 hours now, and he's still intact.

And the thermometer at the window read 60° F. this evening. The long summer is finally over.

Sign of a sick mind?

New decades call for a clean desktop, at least at first. I've been tidying mine, and found all these in the "To Blog" file.

Updates on previous posts:

* Amphipod maternity ward.
The three pairs of amphipods eventually separated into singles. I watched as tiny (barely visible) babies started swimming about. I couldn't tell if they were from the adults present, or some that had been there all along, but too small to see. Some amphipod mothers brood their eggs or young between their thoracic legs; I've been trying to see if these were brooders. They move too fast, and have too many legs, so I'm still not sure.

I don't think this one is brooding. But it's pretty in that polka-dotted outfit.

The whole kit and kaboodle is back in the aquarium.

* The damaged flatworm.
(Recap: this flatworm had been badly torn, right behind the head and across the mouth. It re-organized its body plan to put the head at the whole end, but the old head end still seemed to have a mind of its own.)

The worm rested on my desk for a few days. I provided it with a stone for shade, and a few barnacles to tempt it to eat. One morning it had swarmed over one of them. Over a couple of days, it eased its way inside, and then just sat there, digesting.

Flatworm inside now-empty barnacle shell. The eyes are visible as dots on the left. The "tongue" is the torn end.

When it finally emerged, it went exploring. It was now a good flatworm shape, but still carried the damaged end upright, like a flag; this flag got caught in a crack of a shell. The worm stretched and stretched and stretc......hed, but couldn't get free. I decided to help. I had read that a flatworm may pull itself in two as a way of reproduction. So I pinched the stretched portion, now barely a thread, and it separated. The head went its merry way.

The torn bit sat there, quivering. It was very small, barely a couple or three millimetres across, and I was sure it would die. It didn't. It, like the whole worm, rested for a few days in one spot, but responding by twisting and stretching whenever I tickled it with my soft brush.

Yesterday morning, when I checked, it was no longer in its old place, but had found shelter in a typical flatworm place, on the bottom side of the stone. Which means that it's alive, can distinguish light (has working eyespots again), and can achieve purposeful movement. Wow!

New stuff.

* Reported to BugGuide:

Parasitic wasp, male.

On New Year's Day, a tiny yellow wasp turned up on my fridge door. In the middle of the winter? I photographed it and measured it (3 mm.), looked up hundreds of wasps, couldn't decide on any, and sent it off to BugGuide. So far, they have identified it as one of the parasitic Apocrita, which is not a valid group, just kept for convenience. Still, it's a start.

Another couple arrived at my desk a couple of days ago, a male and a female. Unfortunately, the male died shortly after capture, though I had handled it gently. She is in a pill bottle, waiting for a new male.

The female of the species. The long projection at the tail end is the ovopositor, which she uses to deposit her eggs in her victim.

If these are parasitic, what and where are their victims? The only live things I find around are the Indian Meal moths that hatch out of the bird seed. Could they have been in the pupated caterpillars that I threw to the juncos? Some of them were black, others cream. Maybe the black ones were parasitized. Next time, I'll look more carefully. When I find a male, I think I'll also donate a live caterpillar to the cause, see what happens.

Wing pattern on wasp. Cute little "stigmata".

* Fish art.

Painting by Jaya, 7. Available light; colours should be more alive. I like the seaweed streamers.

The artist, at work on a new idea.

* Just because these made me happy:

Blue mist over Burns Bog.

Almost summer: reflection in Cougar Creek pond, last week.

Hellebore. First week in January, and the flowers are budding out!

And the clean desktop makes me happy, too.

Convalescence. Flatworms have it down pat.

Thanks to everyone who sent me "Get better" thoughts or comments; it worked. I'm feeling much better, and so is Laurie. We're hoping it was just a three-day bug.

I slept all morning, and worked on a video all afternoon and evening. Kept me too interested to feel sorry for myself. (Lemon juice, chicken soup, and camomile tea helped, too.)

I found a flatworm on the White Rock beach last week, and brought it home, damaged. What happened next is in the video:

And now I'm going to bed. Can't risk getting worse again.