Dusty

An earwig walked down my lampshade.

And the light shines through.

Later, she was checking out my screen. I recognized her again by the broken antenna.

Earwig females have smooth, slightly curved forceps (those pincers at the rear); males' forceps are wider at the base, with a tooth just before the strong curve. (See BugGuide photo.)

The name earwig, which literally means “ear creature,” originated from the widespread superstition that these insects crawl into the ears of sleeping people. Moreover, many individuals believed that once the earwig gained access into the human ear, it could bore into the brain. Actually these insects do not crawl into the human ear. (Penn State, Dept. of Entomology)

I heard that when I was a kid. I didn't quite believe it, which saved me a bit of worry; we had earwigs everywhere.

Glowing colours.

Saturday's delight:

Their perfume glows, too; I could smell them before I rounded the corner and saw them.

And Sunday's:

Golden jewel beetle, Buprestis aurulenta, dreaming of trees.

These beetles lay their eggs near injured portions of a variety of conifers, including our Douglas fir, red cedar and pines. The larvae hatch, then bore into the wood, live there for several years - up to 40 years! - burrowing through the tree, until they bore an exit hole and emerge as adults.

This species is the most damaging in its genus. Larvae have been known to take 30 years to complete their development in structural timbers. The emergence holes sometimes penetrate roofing materials which results in leakages. The Orpheum Theater in Vancouver was water damaged after "bargin priced" roofing timbers, cut from trees salvaged from the Taylor River fire on Vancouver Island, produced a large number of adult beetles which bored straight through the tar roof. (Forestry, UBC)

In the shade of the underside of the tablecloth, the colours are strong, but the glitter is gone.

Green or bluish back, with red or copper wing edges. The underside is a bronze colour. This one was about an inch long.

Such a cutie!

I brought in a couple of handfuls of garden soil to top up an indoor flowerpot. A pretty springtail came along for the ride.

Globular springtail, Dicyrtomina minuta forma ornata. About 1 mm. long. I think the translucent globe behind him is a slug egg.

And a newborn weed. Each leaf is about twice the size of the springtail.

Another flower beetle

... with bright orange flower colours.

This one is a flower longhorn beetle, Xestoleptura crassicornis.

The glossy elytra (wing covers) and the orange antennae are diagnostic features.

BugGuide has about 3,600 photos of beetles in the flower longhorn family, about half of them decked out in vivid colours, reds and orange and yellow. I wonder if these are a sign to birds that the beetles taste bad, as is said about some other insects.

But then again, we're just guessing at that, aren't we? Maybe there is no reason at all; it's just the way things happened.

Any volunteers to taste a pretty beetle? I've lost my appetite. Or I'm allergic. Or my taste buds are old. (Any excuse will do.)

Speedy woodlouse

A patch of yellow dead nettle is blooming next door, and my neighbour has moved out, so I picked all the flowers to prevent them from going to seed and invading the world. Or at least, my part of the world.

Hidden beneath a flower head, I discovered a sowbug.

Philoscia muscorum, the  Fast woodlouse. Well named.

Moving the stem around to get a better view of him, I knocked him out onto the table, and he took off running, much faster than any sowbug I've seen before. I chased him down, trapped him, and took a batch of photos, then searched BugGuide. He's a European import, and, while he's built like the sowbugs I see every day (aka woodbugs, pill bugs, roly-polies, etc.), he doesn't act at all like one.

First, he runs. Fast. "Our" woodbugs trundle along slowly enough for me to go for a pill bottle and come back, and still find them on their way to shelter.

Second, he "hides" in the first available shadow he finds. He freezes there, and takes quite a bit of nudging before he realizes he can really still be seen. The usual woodbugs here keep on going until they're invisible.

Fast woodlouse "hiding".

Next, if you flip him on his back, he lies there, playing dead. The other woodbugs either roll into a ball (pillbugs, Armadillidium vulgare), or wave their 14 legs frantically in the air until they manage to right themselves again.

Not so fast, any more. Playing dead.

And last, he and his family live in plants, rather than under some shelter at ground level. This one was on yellow dead nettle; one on BugGuide was found in a rosebush.

In one way, he acts like the others; once he's found a safe spot, he tends to stay put. This critter is still in the dying dead nettle flower that I found him in. As soon as I post this, I'll take him out to the nettle patch and set him free.

UPDATE: I've been asked, on Facebook, how I know he's male. I don't. When I don't know, I randomly pick a sex, because I don't like calling critters with a mind of their own (no matter how feeble) an "it".

A female sowbug may have brood sacs at the base of some of her legs, seen when she's belly-up. I don't think I see any in the photo above.

And the first two pleopods of the five on the pleon (that triangular covering at the tail) of a male are elongated. In the photo, only the last three are visible.

Traplines in the air

It's going to be a good summer for watching spiders. The rhododendrons and cedars on the sunny side of our lawn are festooned already with big webs. The spiders, female Araneus diadematus, aka cross spiders, are still tiny, barely an orange speck in the centre of each web. They'll grow; by the end of the summer some will be up to an inch across, fat bellies showing their success as trappers.

They hang, belly out, upside-down, in the centre of the web. One back leg holds a drag line attached outside the web. This spider has caught and wrapped some sort of fly. An early supper!

"It is common for a web to be about 20 times the size of the spider building it." Wikipedia

Another spider, still waiting for her prey.

These are seriously smart critters. Building a web isn't just a rote operation; every site has its special requirements, and the webs are more elaborate than the simple spiral and ray arrangement shown in children's books.

The spider launches a thread from the top of her chosen location, waits until it makes contact with another branch, then runs down it to glue it down well and reinforce it. She picks a centre and builds another ray out from there, then more until she's filled her space. Then she makes a small spiral in the centre, using non-adhesive silk, glued together where they cross the radials. This is her resting place and launch pad.

8 rounds in this spiral. Note the glue spots at the nodes only.

Then there's a gap, about twice the diameter of the inner spiral. What is function is, I don't know. Maybe it keeps the struggles of her prey out of her private space. Only she really knows.

Then comes the business part of the web. She fills most of the available space with more spirals, built first with non-adhesive silk, then replaced with the sticky stuff. (She eats the first lines; spiders recycle!) She leaves more dots of glue here, spaced randomly, not usually on the nodes.

Outer web. Note the glue spots. The rays are not sticky; the rest is.

And here's where her web differs from the standard drawing; every so often, along those regularly-spaced spirals, she breaks the pattern to make an X, sometimes a Y, sometimes a knot of angled threads. The spider at the top here has a large area like this near the inner edge of her trap; the second spider is a bit more restrained, sticking to a few simple Xs and offset sections.

I was inclined to think of these, at first, as mistakes, the spider losing her way briefly, getting confused. But every cross spider does this; it probably has some function. Maybe it's like the trusses in bridges and roofs, using the triangular shape to add more strength.

What went on in the spider's head? (Or belly, or legs, since her brain is too big to fit in that little cephalothorax, and she's outsourced it to several parts of her body, including the legs. Up to 80% of that little body is brain.) How does she decide it's time to change direction? Does she do the math? Or just sense some instability in the web and X it out?

Questions, questions.

As I sit here typing, a pinhead spider has been busy building a web on a sparrow feather beside my desk. She came down the wall, jumped the gap, and made a beeline for that feather, climbed it and dropped her anchor. How did she know the feather was there? How does she figure that's a good hunting spot?

And what will she be catching. She's so small I barely see her; does she see my desk crawling with little beasties that I can't see? Now I'm itchy!

Iridescence and pink paddles

Details first . . .

Just a lowly worm

Story tomorrow.

2012 critter sampler

December 31st! Already? I'm still doing end-of-summer catch-up!

Alex Wild is curating "Best of 2012" science and nature shots on Scientific American. I was reminded, again, by BugGeek, who posted her collection. Beautiful shots; I've seen them all before, and will review them again tomorrow. Not tonight, because it's hard to blog when you're green with envy.

I looked over my photos, picking out the favourites, not to submit, but just as a year-end summary. And there were too many! I cut them down to just critters; still too many, and I kept remembering more. But I've finally trimmed the list down to a dozen favourite critters, not without difficulty.

Here's the collection: Critters only:

Ant nest uncovered, with the adults rushing to drag the larvae down the holes, out of sight.

Aphid in a moss forest

Caterpillar in morning sunlight

Garden snail, feeding on glass.

Grainy hand hermit, in human hand

Harvestman volunteer

I had trouble choosing my favourite of all the spiders. I have to smile at this fat mama, who does NOT like lime and pepper chips.

Life's an adventure. Hermit crab in aquarium.

Lazy moth in jar lid and morning sunshine.

Spider #2 Long-jawed orb weaver, on hosta leaf.

This was an exciting find; a molting ghost shrimp.

Ok, I give up; I can't choose just one or two spiders! Spider # 3, Ozyptila, the spider-eater's spider eater.

Spider #4, Mother toting her eggs.

Would have been #12, if I hadn't snuck a couple of extra spiders in there. Plume moth on outside wall.

And tomorrow is 2013! I never thought we'd get here. May it be a good year, the best year so far, for all of us!

Wants and wishes

...My argument is [that] because we don't understand animal consciousness, we ought to be opening our eyes to the possibility that a great range of animals, not just mammals, not just birds, maybe invertebrates are conscious as well. It seems to me that by saying we don't understand consciousness, you're not closing off animals' consciousness. You're not denying animal consciousness altogether. You're just simply saying we don't know and therefore it might exist in a much wider range of animals...

That's Marian Stamp Dawkins speaking. She is Professor of Animal Behaviour at Oxford U., and the author of Why Animals Matter. This conversation is titled, What Do Animals Want?

A couple of excerpts:

What we really need is a much more scientific basis for animal welfare than just an anthropomorphic argument. I began to think, how can you define animal welfare in a way that's scientific, that actually leads to proper evidence so the decisions we make are based on good evidence? I came up with a really very simple definition of animal welfare. Which is that the animals are healthy, and that they have what they want.... 

... there's something more to animal welfare than just not dying of a disease. That more is, in my view, what the animals, themselves, want. Do they want access to water; do they want access to cover? Do they want to be with each other? Obviously we can't necessarily give them everything they want. But we can at least find out what it is. If somebody's going to argue such-and-such improves animal welfare, I would say well, what's the evidence that it either improves their health or it gives the animals what they want? If you can't show that, then however much you think you might want it, it doesn't seem to me that it actually improves animal welfare at all.

Read the entire article (or watch the video: 35 minutes.)

And what does a dragonfly want? Supper! And it takes less than a second to catch it. Watch the Science Nation video. And don't miss the frustrated frog (about 49 seconds in); hilarious, if not so much for the frog.

How does a baby bird make his wants known? Well, sometimes, his mother gives him a password. Even before he's hatched out of the egg!

Colombelli-Négrel et al. show that superb fairy wrens go one step further by singing a specific incubation song to their in-egg embryos, which helps them to oust parasitizing cuckoo chicks that have not learned the brood's “password.” To ensure that both parents are in the know, females also incorporated their incubation song into begging calls given to their male partners, resulting in males also being more parental to chicks singing the right song.

 The entire (brief) article is at ScienceMag.org. I think registration is required, but it's free and fast, and gives you access to years of interesting science news.

And on to the wishes pretty pictures! First up; a whole passel of brilliant sea spiders. They're not really spiders, but Pycnogonids, but they sure look spidery. And yes, we have them in BC, too, but sadly (for me) not in the intertidal zone. These, for example, live at a depth of 2200 metres (1.4 miles).

Vent sea spider. Photo from Wikipedia.

Pycnogonids are so small that each of their tiny muscles consists of only one single cell, surrounded by connective tissue.

 More pics: I am always impressed by PSYL's photography; from insects to birds to scenery, he brings it all to life. He was recently working in the extreme north of the Yukon (about 1500 miles north of here, in the Vancouver area), and posted photos of a hike around Ivvavik. Beautiful country, a must-see!

My son-in-law motorcycled up to Inuvik, just a few miles east of there, this summer; did I mention that here? I followed him on Google maps. They had sent one of their trucks up the highway, and I could "stand" on the road and see the country he was driving through. I so wish I could make the trip myself!. All that wide-open space; all that brilliant colour, and the northern lights overhead!

Back to the topic at hand; PSYL's final photos are of tors. I had never heard of these; they're like huge rock walls marching across the landscape. Wikipedia explains how minerals deposited in granite cracks have persisted over millenia, while the granite eroded away to gravel, leaving the huge mineral walls behind.

One final link: someone is missing a large tub of scallop guts. Have you seen it?

Wax, feces, dish detergent, and a baby scale

My Schefflera was harbouring scale bugs again. I had cleaned them off in January and the plant did fine all year, but now that the heater comes on occasionally, and the light is lower, here they are back again.

This time I didn't wait until the leaves were falling off. (Well, one or two did.) When I saw the plant shiny and sticky with leaked sap, I checked, and found the scales.

This time, I removed the plant immediately to the shower, where I sprayed it well with household cleaner, then washed that off with a strong, lukewarm shower. Then I drizzled the whole plant well with dishwashing detergent and left it to soak. After about 15 minutes, I showered it again.

When it was dry, I brought it back to the light and inspected it, finding about a dozen scale bugs, which all appeared to be dead when I inspected them under the microscope.

Large scale bug, about 1 to 1.5 mm long, upside down, and apparently dessicated.

They like to settle along the veins of the leaf and on tender parts of the stems.

Scar, where the bug has been washed off, leaving a ring of waxy strings.

The mother scale bugs shelter their eggs and young under their wax and feces coating, even after they have died. How about these? Did the detergent get under those umbrellas? Were there future scales in there? I flipped all that I'd removed entire on their backs and examined them. In one which looked as dead as all the rest, a hint of motion caught my attention. It was a baby, waving four little legs in the air, transparent, short legs, like blond hair with elbows. The only one; all the rest had been washed away.

Last January, I wondered about those "eye" spots, so visible in the top photo. Someone was asking about them on BugGuide, too, and not getting an answer. I wandered off down the web, and found a USDA site dealing with scale bugs. Down through the halls: Scale insects -- soft scales -- to a page with the anatomy of 46 species of scale bugs. Mine turned out to be Coccus hesperidium, the brown scale. On its page, there's a detailed description and a drawing with definitions of the parts. There is no mention of eyes or eye spots.

What there is, in abundance, are pores. Large pores and micro-pores, and double pores. Some excrete wax, some the honeydew that coats the leaves. Two of those could be what looks like eyes. I've left a question at BugGuide about it.

And it seems that this method, a warm, soapy shower and soak, actually works. A lot more fun that scraping lumps off sticky leaves, too. But I'll still need to check for newborns next week. The plant looks fine.

Great Expectations - Interplanetary Rock Flipping Day, 2012

Is there a space rock in our future? Why not? We've flipped rocks everywhere else, haven't we?

This weekend, dozens of intrepid rock flippers have ventured out into the world to discover the wild critters, known and unknown, that inhabit the secret places. So alien to us they are, and yet so like us in many ways; our cousins, actually.

Here's a partial list of who we are and what we found. (Some reports are still to come in; I've heard that I should expect moose. We've got camels and leopards already.)

In no particular order:

• Troy Bartlett (founder - or founding member - of BugGuide; we owe him a debt of gratitude) took some amazing harvestman photos. See them on Nature Closeups. Butt shot! A stare down!
• Alex Wild, posting in   Scientific American, joins us for the first time, with ants and millipedes and an ant cricket from his backyard.
• Roberta flipped river rocks; some of her findings are posted in Growing with Science, the rest in Wild about Ants.
• Lynda at Mainly Mongoose doesn't flip any rocks, but finds toothy Dwarf Mongooses underneath some, anyhow. 

'There are older and fouler things than orcs in the deep places of the world.'

• Margy, at Powell River Books Blog, for the second year running found no crawling or creeping critters. Not for lack of effort; what's going on with the shoreline at Bellingham Bay? At least she got some eelgrass this time.
• Patrick, a student of lunar petrology (Told you we'd gone interplanetary!), blogs at poikiloblastic.    I never knew a rock had defense mechanisms before! And he has a photo of a cute (really!) slug.
• Hugh, at Rock, Paper, Lizard, gifts us with another Interpreter wildlife expert story. "A rubber boa?" I'd never heard of these before. Yes, they do exist. Did they find one? Read the story.
• Clytie, at Random Hearts remembered. Didn't find critters, but there was a pretty heart, so all is well.

Some kind of twirly insect casing ...

• Olivia, at Beasts in a Populous City, learns a modicum of humility.
• Benet, at Walking with Henslow, flipped rocks in Starkweather Creek. Sow bugs with lime green spots!
• Pablo at Roundrock Journal, reports on another of his biodegrading experiments, and finds a cricket and a companion rock flipper; an armadillo.

Some kind of stripy insect casing ...

• Bill, at Fertanish Chatter, checks in with some pretty millipedes, a "nifty" spider, and is this a toad bug? A sight for sharp eyes!
• And then there's a toad, no easier to see than the toad bug. Judy's husband found it; Judy blogged it at LilacGate.

 Then husband said "What is that?" and I finally saw the toad, settled in for the winter.

• Kate St. John, at Outside my Window, flipped a rock, found a leopard. And a pair of camels!
• Rebecca in the Woods; an ant and a beaver. (The beaver was not under the rock.)
• Bug Girl posted an announcement on Skepchick, and a couple of flippers turned up in the comments. Here's Greenstone123's story. Ant kitchens! And scribe999? Don't give up. Not even in Jersey!
• Also in comments, on Rebecca's blog, Madhu in Sri Lanka found a couple of ants.  And Christopher (in Missouri) found ticks, and got too many tick bites to count. It's a wild and dangerous world out there!
• And on to the Flickr group! We have photos from Sara (mamasara4), from Georgia (georgiabkr), Dean (Ontario Wanderer), Benet (benet2006), Upupaepops (Upupa4me), Bug Girl (bug_girl_mi), and Pablo (Paul Lamble). Beetles, crickets, slugs, and so on, including an angry isopod, making threats to Upup...'s fingers.

Not under a rock; all around the rock piles. In blazing sunlight, on my grandson's shirt. Fuzzy, but I like the contrasts.

• And then, there's me. I still haven't written up my post. (That should give comfort to a few others who haven't logged in yet. There's still time!)
• NASA's stone is still unflipped. Of course, they take years, decades even, to get anything done. And there's always that transmission time to take into account.
• Update: Here's my post: Hard-scrabble existence.
• And an e-mail from Gail Bellamy reports, "Jamestown, New York----nothing but a few small ants----then a split large rock with the first layer had 2 black ants, but the bottom had a large fat toad resting comfortably. All are still in place." She doesn't include photos, unfortunately.
• Update # 2: Fred sent in his report from the Muskrat River, Ontario, via e-mail attachment. I've posted it here.
• Update # 3: And Mark, operating on the Celtic calendar, sent in his results today, Sunday the 16th.
• I think that's the lot. Have I missed you?

I'll send an e-mail with the list to all the participants, but feel free to copy this list and paste it on your own blogs. Thanks for Rock Flipping with us!

Here today, gone tomorrow

We had a good, hard, pelting rainstorm a few days ago, all day long. Across the street in the vacant lot, that means we'll find big puddles, slowly draining through the hard-packed clay soil. They're temporary ponds, lasting only a few weeks unless it keeps on raining, but while they last, they're busy. Crows congregate around the larger ones, bathing and arguing. A few times, we've found mallards resting there. Insects drop in for a drink; beetles and snails rest in the cool mud.

At the far end of the lot, I stopped to inspect a new pond, a few inches deep.

About a quarter of the puddle.

The top layer of clay had dried and cracked; the cracks remain, even underwater.

But what were those tiny specks in the water? When I bent down to look, I could see that they were swimming about. Hundreds upon hundreds, thousands of them, as small as dust, and about the same colour as the yellowish mud. I took a photo with the flash, to see if that would make them more visible.

They're all over, but hard to see against the muddy bottom.

Zooming in, no flash. There are a few springtails on the stick, about 1 mm. long, slightly bigger than the swimmers.

The same photo, cropped. Now the critters are recognizable as ostracods.

Ostracods are small crustaceans, typically around 1 millimetre (0.04 in) in size, but varying from 0.2 millimetres (0.008 in) to 30 mm (1.2 in) in the case of Gigantocypris. Their bodies are flattened from side to side and protected by a bivalve-like, chitinous or calcareous valve or "shell". (Wikipedia)

Under a good lens, an ostracod looks sort of like a swimming clam. If the light is right, a hint of the body can be seen through the shell; imagine an amphipod, all 14 legs vibrating constantly, inside a clamshell, with a few legs or antennae occasionally peeping out.

They live in both fresh and salt water environments, from the poles to the tropics. I have often found them in sand or seaweed from the intertidal zone. Some 65,000 species have been identified; there are probably many more to be discovered.

These ones, the ones in my puddle, have selected a particularly difficult environment. The water is clear, there is plenty of vegetation to serve as food, but if the sun shines, their home will disappear in short order. Some species of ostracod will live for up to a year; these guys won't have the chance. A few weeks, if they're lucky.

At one end of the pond, there is a mass of fibers. Old moss? Leftover trash, well rotted? I couldn't tell. But the ostracods were less active around them, easier to photograph. Click to see the photo full size; you can see the clam shape, and on one, up in the right hand corner, a tentacle peeping out.

An ostracod at home in a bowl. The one eye is plainly visible. Some ostracods have two.

How do these animals manage to live under these conditions? First, they don't waste time. They spend up to 80% of their lifespan laying eggs. These eggs are resistant to dessication; they can "sleep" in dry soil for years, until the rains come again. Some adults and young are also able to go into stasis when the pond dries up or freezes.

And also, they reproduce in vast numbers. Most of the ones in this pool won't survive the dry times ahead, but enough will to produce the next generation.

Also in the puddle were a number of these swimming bugs, very fast, zipping around the bottom, occasionally popping up to the surface for a second or two. I think they may be the Acilius diving beetle.

And a water strider, one of two.

Examining the photos, looking for a clear shot of an ostracod, I discovered this snail on the bottom. It is a species I have not seen here before.

The white oval to the left of the snail looks like an abandoned clam shell. (Look at the photo full size.) This may be a molted valve. Like other crustaceans, the growing ostracod  has to abandon the hard outer shell, in the case of freshwater ostracods, 8 times.

There's an excellent YouTube video here, showing the live ostracod kicking inside her shell. Watch all the way to the end, when she suddenly starts zipping around.

And this is mind-boggling:

Ostracods possess the largest sperm in the animal kingdom in both relative and absolute terms. Ostracod sperm can be up to ten times the length of the male's body! Some male ostracodes need a special organ (Zenker's organ) to aid in sperm transport.

However, about a third of freshwater ostracod species don't worry about that; they are parthenogenic, and need no males to reproduce.

Scales, honeydew, and a good bath.

The leaves were falling off my Schefflera houseplant. Just a few, at first; I picked them up and thought nothing of it. Then, last week, there were more every day. Saturday, I finally got around to really looking at the plant, and discovered that it was covered with scale insects and their excretions.

A plague on all their houses!

A closer view. Scales, sticky sap, bubbles of honeydew.

These are soft scale insects, Coccidae, feeding on the plant juices, gradually killing their host. They don't look like insects; all that's visible is a shell glued to the stem or veins of the plant, like a limpet to a rock. But the limpet wanders about; these do not.

They are probably all females; some species reproduce by parthenogenesis, without the need for a male. In other species, the males live for only a short time; they do not feed.

Female scale insects attach themselves to a handy location, and settle down to eat and lay eggs, 1000 or more in a season. They cover themselves and their eggs with a thin coat of wax and feces. As they feed, they excrete excess liquid through pores in various places; this is a sweet, sticky substance, called "honeydew". It covers the leaves and stems, attracting fungus spores and, on houseplants, dust.

Little bird from Chinatown apologizes for not eating the bugs.

I broke off the stems and leaves where the scale insects were thickest. Some of the scales fell off, so I collected them to get a better look at them.

Side view, showing the waxy cap, and the mass of eggs or young underneath.

When the female dies, her eggs remain protected underneath her dead body until they are ready to hatch.

The largest scale I found, just over 3 mm. (1/8 inch) long. She was dead, her babies long gone.

Several sizes and conditions. Upper left, on top of the pile, what looks like white wax emerges from a central rear pore. Extreme right, center, a dead, empty shell, upside-down.

Most of the scales that had fallen off seemed to be dead and empty, but as I examined them, one started to rock. Then a very tiny, almost transparent baby crawled out from underneath. As I watched, others joined her.

Medium -sized nymph, about 1.5 mm. long.

The tiniest crawler, half a millimeter long. If you look very closely you can see a hint of legs. She could move at a pretty good pace for her size.

I don't know if those two black spots in front are eyes. Someone asked about that on BugGuide, but got no answer.

Only the newly-hatched insects crawl about; once they've found a good feeding spot, they settle down. In some species, they lose their legs entirely.

And now it was time to rescue my poor plant. The leaves I had removed went into the garbage, sealed in a plastic bag. I put the Schefflera in the shower and hosed it down thoroughly with lukewarm water and lots of soap. I took off the top layer of soil and scrubbed the pot, too. When it dried, I checked it over and discovered a couple dozen more scales; these I squashed.

Tonight, the plant looked healthy, but I found another few small scales along the veins of leaves, and removed them. I will have to continue monitoring until I know all the nymphs are gone.

There's an excellent photo of one of these, by Scott Justis, on Flickr, here's Wikipedia on the scale insects, and the USDA Systematic Entomology Laboratory, has a good discussion of the Coccid family.