Father’s Day we did a family hike up Lambs Canyon. I’ve always liked this trail; it’s some of the closest, most easily-accessible, cool, shady, moist, North-slope Wasatch forest to the Salt Lake Valley. AW was in power-hike mode, but I was still groggy from the High Uintas Classic road race the day before, and a monster pancake breakfast the following morning. Soon she and Twin A left Twin B and me far behind, bringing up the rear.
Tangent: Bird Whisperer, at the ripe old age of 11, has proven to be an Early Adopter of the teenaged habits of staying up late, and effecting maximum laziness during the day to compensate. He accomplished this hike by repeatedly striding ahead on his long legs till he caught AW and Twin A, then lying down in the trail and “napping” till Twin B and I caught up.
So I ambled along up the trail with Twin B, who invariably brings up the rear on hikes not because she is slow or lazy, but because she is a chronic dawdler. But dawdling has an upside: she notices more bugs and plants than the other kids. The lower reaches of Lamb’s Canyon trail are the shadiest, with lots of leafy green ground cover trailside. Twin B asked me the names of flowers as we picked our way along, nearly all of which were familiar*.
*Both Canada (pic left) and Blue Violets (pic right)are in bloom in several sports along Lambs Canyon trail right now. Look at me- 2 pics in a footnote!
But about the 4th or 5th flower, I hesitated. It was small, white, 5-petaled and low to the ground. I wasn’t sure I’d seen it in bloom before, but I recognized it from the guides. It was a Woodland Strawberry, Fragaria vesca.
Strawberries are cool for so many reasons. On the one hand, they’re a non-descript little forb sprouting fairly standard little white flowers. But in their form, genetics and history- both natural and cultivated- they’re fascinating.
Woodland Strawberry is one of 2 wild Strawberries growing in Utah, the other being- get ready for it- Wild Strawberry, F, virginiana. Both have broad ranges, and are divided into geographic subspecies. (Our local subspecies of Woodland Strawberry is bracteata.)The ranges of the 2 species are so broad that it’s not quite clear exactly what was their native, pre-settlement range, but it seems pretty certain that Woodland Strawberry is native to both Eurasia and Western North America, while Wild Strawberry is native only to North America.
Side Note: Confusingly, F. vesca in Europe is sometimes referred to as “Wild Strawberry”. But it’s F. vesca they’re talking about. In this post Woodland Strawberry is F. vesca, the diploid species native to both Europe and Western North America, while Wild Strawberry is F. virginiana, the octoploid species native to North America (only).
You can tell Woodland and Wild Strawberries apart by their leaves. Both have toothed leaves, but the central, pointy tooth at the tip of the leaf is much smaller than the other teeth on a Wild Strawberry. On a Woodland Strawberry it’s more or less the same size.
There’s another difference that’s not visible- or at least without a microscope. Woodland Strawberry is chromosomally diploid, with 2 sets of 7 chromosomes, or 14 total. But Wild Strawberry is octoploid, with 8 sets of 7 chromosomes for 56 total. Polyploidy* is rampant in strawberries with different species possessing 4, 5** 6, 8 and 9 sets of chromosomes***. In the last decade, an Asian species, F. iturupensis, of the Kurile Islands (Russia, Pacific coast) has been discovered to sometimes possess 10 sets- or 70- chromosomes!
*I initially explained polyploidy in this post. But I’ve covered so many examples of it since then, if you don’t know about it by now you are just not paying attention…
**We’ll see a pentaploid strawberry later in the post.
***Triploids don’t occur naturally, but have been produced as cultivated hybrids.
There’s some suggestion that polyploidy may (but not always) be associated with larger fruits. The strawberries we buy at the supermarket- and to which we will return later in the post- are octoploid. The Woodland Strawberry genome, BTW, has recently been fully sequenced. Its small size* and short generation time of 14-15 weeks (in a greenhouse) make it an excellent model genome for Rosaceae, the Rose family, with whose many other members most of its gene sequences are shared.
*The genome, not the plant. Although the plant is small too, I suppose. But that’s beside the point.
Despite having a “typical” genome*, the “fruit” of a strawberry is anything but typical. In fact, botanically speaking it’s not technically a fruit. Actually, even that’s not quite right: the part you think of as the fruit isn’t, but there is real fruit on each strawberry- dozens of them in fact.
They’re the little “seeds” sprinkled all over the skin of the “berry”, which aren’t actually seeds- it’s like everything is bass-ackwards with this “fruit”- but achenes, the same dry fruit architecture we’ve looked at before in everything from Sunflower “seeds” to Dandelion “seeds.” Fragaria achenes are thin-walled, each containing a single seed.
*At least in the case of diploid F. vesca.
Botanically speaking, a fruit is a seed ovary. The red juicy part of the “berry” isn’t ovary; the ovaries of the little white flower will eventually develop into the achenes on the outside of the red juicy part. The red (well, not always, many strawberries are more white in color) juicy part is technically a pseudocarp, the botanical term for a fruitlike structure composed of tissue that is not derived from the ovary wall. Pseudocarp tissues come from other parts of the flower, such as the calyx, or- as is in the case in a strawberry- the receptacle, which is the end of the stem to which the various parts of the flower are attached. In a strawberry, following fertilization, the receptacle develops and swells to many times its size, creating the “berry” we eat.
Lots of other fruits we eat are pseudocarps. Figs- which we looked at last year down in Costa Rica- are formed out of a big, hollow receptacle, with the flowers- which are fertilized by symbiotic Fig Wasps- attached to the inside wall. A pineapple is a pseudocarp that’s sort of a receptacle-conglomerate- grown from the receptacles (and other parts) of many separate flowers. Pome fruits, such as apples and pears, are also pseudocarps; the core is the actual fruit. A pseudocarp is also called an accessory fruit*.
*Older sources also sometimes call them “false fruit”, but I guess that term’s not really used by botanists anymore. Maybe they were afraid of hurting the fruit’s feelings or something.
Strawberries are a very effective dispersal strategy. Many birds eat them, and pass (undigested) the achenes, far from the parent plant. A great example is the Chilean Strawberry, F. chiloensis, whose range spans the West coast of the Americas from Chile to Alaska, its seeds having long ago been spread by migrating birds.
But one of the most interesting and unusual things about strawberries are their relationship with humans, and the history of their domestication and cultivation.
It’s interesting to think about where the fruits and vegetables we eat were originally domesticated. Wheat, barley, rice and millet are all native to, and were domesticated in, the Old World. Corn, potatoes and squash were first domesticated in the New World. Some crops have a back-and-forth history: Sunflowers (which we looked at in this post) are native to the New World, but were artificially selected/domesticated in the Old World.
But strawberries are different* in that they were domesticated independently in the Old and New Worlds. To be fair, the species domesticated were different. F. vesca was first domesticated in Ancient Persia, and it is still cultivated and used in Europe for various sauces and jams. F. chiloensis was domesticated in South America, and bred for larger size.
*Unique maybe? Is there any other crop domesticated in both Old and New World? I don’t know.
But neither the Woodland nor the Chilean Strawberry is what we buy in the supermarket. Commercial strawberries are F. x ananassa, a hybrid of 2 strawberries we’ve already mentioned- the Chilean and Wild Strawberries. Both are New World species, but in another back-and-forth story, their hybridization and domestication happened in Europe, and even more interestingly, by accident, F. virginiana and F. chiloensis being grown in the same garden hybridized in the 19th century. The hybrids display both the sweet flavor of virginiana and the size of chiloensis.
F. x ananassa is chromosomally octoploid, like both of its parents. Both Wild and Chilean parents provide 4 sets of, or 28, chromosomes. But in California, Chilean and Woodland strawberries sometimes hybridize naturally. When they do, the Chilean (octoploid) parent provides 4 sets of, or 28, chromosomes, and the Woodland (diploid) parent provides 1 set, or 7, chromosomes resulting in the naturally-occurring pentaploids I alluded to above. It’s not known whether these 35-chromosome hybrids, known botanically as F. x bringhurstii, can reproduce sexually, but since strawberries also reproduce vegetatively via runners, they’re not uncommon.
Next time you eat a strawberry, look at it and think about it for a moment. Imagine if the receptacle didn’t swell up and get red and juicy, but just stayed, well a receptacle. And instead the fertilized ovules, instead of becoming tiny, hard, dry achenes, swelled up, each into a juicy little fruit of their own. You’d have something completely different. You’d have (more or less) a Raspberry*.
*Or a Blackberry, or- for a local native example we’ve looked at previously- a Thimbleberry, or pretty much any “berry” in the genus the Rubus. I just picked Raspberries because they’re red. And delicious. And the seeds always bother me in Blackberries. Technically, BTW, Raspberries/Blackberries/Thimbleberries et al aren’t true fruits either, but rather aggregations of multiple separate fruits. Blackberries, I’ve heard, have a frighteningly complicated/confusing taxonomy. Let’s hope I don’t run across any too soon.
It’s cool to think about “what-ifs” in evolution and nature. It’s even cooler when it turns out that a “what-if” is real after all. In the case of Strawberries and Raspberries, you can check out a real-life what-if pretty much anytime you want at the local supermarket.
Summer! Winter is nice and all, but what I daydream about back in January and February is this:
Zipping through a shady forest of endless white Aspen trunks is the sweetest part of living at the foot of the Wasatch.
Over the next couple of months, blooms of wildflowers will appear and wane like waves of color washing across the forest floor. Within a week or so, Columbines will start popping up, and as they quickly wilt Wild Rose, Arrowleaf Groundsel and Sticky Geraniums will flower, the latter dominating the forest floor by late July. The Serviceberry bloom has passed 8,000 feet and will soon crest, so be followed first by Chokecherry, then Ninebark and Elderberry. Two months from now the same forest will be sprinkled with Showy Goldeneye, Aster and Paintbrush. When I think about it, I don’t know why a) anyone lives anywhere else, or b) why everyone in Salt Lake Valley wasn’t up in the mountains on Sunday.
Side Note: Speaking of the Serviceberry here’s a clip of descending* through a nice blooming stretch around 7,700 feet.
*I’m going so slowly here because it’s a very steep, twisty, brushy, off-the-saddle descent- Lower Finesse trail, above Pinebrook. It looks easy, but it’s not (SBJ can vouch.)
(Aborted) Tangent: I started a tangent here but canned it, not because it wasn’t a good topic or was too controversial or anything, but because the follow-on to point b) above gets into a whole motivation-direction-meaning/purpose of life thing that I’m not ready to tackle at the present moment. The “present moment” in this instance being my hotel room in San Jose, California, where, as soon as I am done with this post, I plan to flop into bed, watch an episode of South Park, and go to sleep.
Nested Tangent: Which reminds me- I have this awesome new “theory I call the South Park Theory, which states that the best window into someone’s true inner character, beliefs and overall world view is their favorite South Park episode.
*Mine’s the Critter Antichrist episode. OK I might be over-sharing here.
Yes. that’s my guilty hotel-pleasure. No, not the South Park part- I watch that whenever I can. The TV-in-bed part. We don’t have that- a TV in the bedroom* at home.
*And neither should you. Wish you and your spouse had a better sex life? Get rid of the TV in the bedroom. You think I’m being snarky, but it is a fact. Poll your married/partnered friends. Your good friends. Your Friends-Who-Will-Tell-You-How-Often-They’re-Having-Sex-Friends**. Then ask those same friends if they have a TV in the bedroom. You’ll be like, “Wow, that Watcher guy was totally spot on. He must really know something. Maybe I should start paying attention to his plant posts…”
**What’s that? You don’t have any friends you can talk with about that kind of stuff? You need new friends.
New(tiny)Flower!
The weekend before last AW and I did a rainy hike up in Park City. Alongside the trail I noticed tiny spots of color, miniscule flashes of white on spindly stalks rising from the forest floor. In the week+ since I’ve been seeing them everywhere, another one of those little things that’s invisible till you see it, and then suddenly it’s everywhere.
It’s Small-flowered Mitrewort, Mitella* stauropetala, also called Side-flowered Mitrewort, for reasons we’ll get to in a moment. Mitella, the Mitreworts**, is a genus of ~12 species native to North America and Asia that have teeny flowers, and grow low to the ground in moist spots in the forest. Mitreworts have a curious and dramatic form that would be more striking if they were larger: the round-ish leaves form a low, maybe 4-6” “canopy” above the ground, while the flowers are borne on tall, leafless stalks rising up 12-16”. Imagine if Ninebark or Wild Rose bore its flowers on 15-25 foot high agave-like stalks that towered far above their main bushes; that’s a Mitrewort.
*I got the family right, but struggled on the ID till Sally pointed me to the genus. Thanks, Sally!
**The “mitre” in question refers to a bishop’s traditional hat***, to which the flowers of some species supposedly bear a resemblance. (I don’t see it.)
**Note to Utah readers: I mean a traditional, European-type bishop’s hat, like that of a Catholic or Anglican bishop, not a baseball cap with a big “Y” on it.
Mitreworts belong to the Saxifrage family, Saxifragaceae, and so are more closely-related to Woodlandstars and Wax Currants than most anything else around that we’ve looked at.
Side Note: Woodlandstars are already blooming everywhere between 7,500 – 8,000 feet. And Wax Currant, Ribes cereum, is blooming right now (pic right) at the same elevations. I’ve blogged about this shrub before (last summer in the Henry Mountains), but this is the first year I’ve noticed it blooming in the Wasatch. Wax Currant has a leaf that’s very similar in shape/form and size to that of Ninebark*, and grows in similar, shady, forest-floor environments. But the flowers, though both white, are very different in form, so this is an easy time to pick the 2 shrubs apart. Once you do, you’ll notice that the leaves, while similar in form, have very different finishes; Wax Currant leaves are more “crinkly” in appearance, and are covered with tiny little hairs.
*Result of convergent evolution, as these 2 shrubs are not at all closely-related. Ninebark is more closely-related to Apples or Pears, and Wax Currant to Magnolias.
The “side-flowered” moniker comes from the tendency of all flowers to bloom on the same side of the stalk, a trait peculiar to this species and which can be used to help distinguish it from other Mitreworts.
M. stauropetala ranges across the Pac-Northwest and down the Rockies into Utah and Colorado. But there are 2 varieties of the plant; ours, var. stenoplata, has slightly smaller-flowered than the common Pac-Northwest, var. stauropelata. And the origins of our variety aren’t entirely clear; it’s suspected that var. stenopelata may be the result of a past hybridization event between var. stauropelata and M. trifida, Threepart Mitrewort, a species occurring over much of the same range.
Extra Detail: Goshute Indians used the roots of M. trifida to brew up an infusion they used to treat colic.
If so, SF Mitrewort would be another great example of a hybrid origin of a pretty common Wasatch wildflower. Longtime readers may remember that 2 years ago we looked at a super-ubiquitous likely example of such a past hybridization event- Cutleaf Balsamroot, which BTW is in massive bloom all over the place.
Besides the Balsamroots, SF Mitrewort has something in common with another group of plants we looked at more recently- the Yuccas, in that it also has a dedicated moth-pollinator which is dependent upon it for reproduction. The moth Greya mittellae lays its eggs exclusively in SF Mitrewort flowers, and pollinates them in so doing.
Extra Detail: To be sure, the Greya-Mittela story isn’t as fantabulous as the Tegeticula-Yucca deal. The Greya moth doesn’t make any kind of a special side-trip to effect pollination, and, although the moth is wholly dependent upon the flower, I believe that SF Mitrewort is also pollinated by syrphid flies and Osmia bees, (though I came across conflicting pollination info in my research and can’t confirm this for certain.)But it’s still a cool story. Yucca Moths and Greya moths, BTW are fairly closely-related, both belonging to the family Prodoxidae.
Oh, BTW, I finally got a half-decent Osmia shot (pic right) this past weekend. Check out the pollen grains all over her.
So it’s an interesting little plant, with an appealing form and a cool story, but that’s not what I really catches my eye about it. No, what I absolutely love about SF Mitrewort is the phenomenal beauty of the flower. Check this guy out (pic, below right). If these flowers were the size of Balsamroots or Columbines they’d be considered, hands-down, one of the most spectacular flowers in Utah.
The architecture is lovely. The broad, round-ish “petals” (usually 5, sometimes 6 of them) are actually sepals. The true petals are those long, tripartite white stalks are the true petals. Following pollination, the (true) petals soon drop, but the sepals linger a while longer. Later in the season, the sepals too will drop, leaving behind little cups bearing tiny black seeds.
After 2 years at this project I’m still finding new wildflowers, but if you’ve followed this blog for a while, you’ve probably noticed that the more recent flowers I’ve posted about- SF Miterwort, Utah Buttercup, Spring Whitlowgrass, Star-Flowered False Solomon’s Seal- tend to be smaller. These are the flowers I missed the first year or so when I was smitten with the bigger blooms. I sort of feel like this year I’m filling in the “white space”, or I guess “green space”, of my mental map of Wasatch forests.
So how does a Sowbug Killer get past a Woodlouse’s armor? After the shameless cliffhanger I left you with Wednesday, it had better be a good story. And you know what? It is.
Tangent: I have to break these TdF-type posts up oftentimes because I just can’t steal enough time away in a day to bang the whole thing out. I wish that weren’t the case, because I usually get the idea for a post pretty quickly after I learn about something. But I can’t magically just “spray” the idea onto the screen; I have to piece it together, write text to support it, then build my Expand-O-Graphics. Time, time, time. When you get down to it, the Secret of Life is this: the only thing you are given in life is time. The only thing you have to figure out in life is what to do with the time you have.
The short answer is that there are multiple ways to kill a Woodlouse, and the method employed depends on the particular species of Dysdera spider. Which brings us back to species.
The Amazing Story of Dysderid Evolution
In Part 1 I mentioned in passing that D. crocata is 1 of more than 200 species of Dysdera, and that it’s the only one with a worldwide distribution. All the rest are limited to a “Greater Mediterranean” region, which includes several island chains off the West coast of North Africa. That in itself is interesting enough- 200+ species, only 1 outside of the home region- and that one is all over the world. Far out- eh?
But it gets even weirder when you look at their distribution across those Atlantic island chains.
Of those 200+ species, 5 are endemic- that is native to no place else in the world- to the Madeira Islands. 1 species is endemic to the Azores, another 1 endemic to the Cape Verde Islands, and 1 more to Selvagens Islands. Guess how many species are endemic to the Canary Islands? 43. that’s right- out of 200+ Dysdera species in the world, 43 of them are endemic to the Canaries, an archipelago of 10 islands in the Atlantic Ocean about 60 miles off the coast of Morocco.
Side Note: The Canaries are interesting for lots of other reasons. Canary Island flora has a few other head-scratchers like the Dysdera thing, and the archipelago is loaded with dozens of species of endemic snails, beetles and millipedes. And interestingly, for a group of islands that’s been known and studied for centuries, geologists still can’t quite agree on the exact processes and forces behind its origins. Most major islands have a pretty well-agreed upon modern origins story: the Hawaiian Islands are the result of “hot spot” volcanism. New Caledonia is a fragment of an ancient supercontinent. But the origin of the Canaries, while clearly the result of volcanic activity, is still controversial. Like Hawaii, there’s a general age-directional trend: the Eastern islands are the oldest, dating back as long as 20 million years ago, while more Westerly Tenerife is probably only around 2 million years old, But then confusingly it appears that even more-Westerly La Gomera is older than Tenerife, breaking the age-directional trend. And even more confusingly, the eruptions that created Tenerife joined 3 pre-existing islands which date back 6 – 16 million years. Westernmost El Hierro is less than a million years old. It’s suspected that the archipelago’s unique origins may be due in part to its being so close to a passive continental plate (Africa). In any case, it’s a complicated place.
It appears that the Canaries have been a secondary center of Dysdera of evolution in the same way that Mexico may have been a secondary center of Pinus evolution- some pioneers got there, then speciated and radiated. The endemic Dysderids of the Selvagens, the Cape Verdes and (possibly) the Madeiras all appear to be descended from Canary-based ancestors. (The Azores species looks likelier to be the result of a separate colonization from the mainland.)
But the Canary-Dysdera story is maybe even more interesting than the Mexico-Pinus story in that it is almost certainly the result of multiple colonizations. 36 of the 43 endemics look to be descended from a common colonizing ancestor, but the remaining 7 species are trickier to figure out, and appear to be the result of between 1 and 3 separate colonizations.
Extra Detail: An interesting question is how these original colonists got to the Canaries, as they arrived long before people were sailing around in boats. Many juvenile and/or smaller species of spiders travel long distances via “ballooning”, where they trail strands of silk that are caught by wind currents, lifting and carrying them through the air. But no Dysderid has ever been known to balloon. A more plausible dispersal mechanism would be rafting via seaborne mats/clumps of vegetation/debris/soil washed out to sea. Such mats/”floating islands” often emerge from the mouths of rivers in rainy season.
But the rivers that flow out to Morocco’s Atlantic coast, which pass through arid, relatively low-vegetation areas, don’t produce such “floating islands” of vegetation/debris/soil. But in the not-too-distant past, Morocco had a much different climate- cooler, wetter and more forested, and some of the river valleys have topologies which suggest much greater, more powerful flood flows in times past.
Wow. What a totally cool story. But what already does any of this have to do with eating woodlice??
How To Kill A Woodlouse
I’m getting there. Now it turns out that these 200+ Dysderids, though overwhelmingly running hunters, have adapted to various hunting techniques, environments and lifestyles*, including both choice of prey and method of attack, and some of those adaptations can be seen in their chelicerae (fangs)**.
*A few Dysdera species are partially or completely troglodytic. D. unguimmanis, which is native to Tenerife, is unique in the genus in that it has no eyes. It spends its days deep inside dark ocean caves.
**Spider cheliceraea are thought to also vary in some species as a result of sexual selection. But in all known Dysdera species, chelicerae morphology is the same across age and gender, so it’s thought not to be the case with these guys.
To review, chelicerae- which we looked at when discussing Tarantulas in the Oquirrh Mountains- are mouthpart/appendages used by arachnids to grasp and handle food; in spiders (order Araneae) they’ve evolved into hollow venom-injecting fangs. Spider chelicerae have 2 segments- the base, and the fang. Across Dysdera species the form and length of both segments vary considerably and seem directly related to both choice of prey and method of attack.
Wow, what a great Expand-O-Graphic! I’ve really taken things up to a new level, haven’t I? Haha! Just kidding! The inset is a photo I copied from here on bugguide.net. No, I didn’t have a fang photo anywhere near that good, in part because I am a lame photographer, but more to the point (and in my defense) because when I photographed the spider I had no idea what it was, nor that its fang morphology would be so important to the story. In any case, here’s a (lame and blurry) non-cheater graphic.
Specifically, there are 3 primary attack modes used by Dysderids against Woodlice, along with a number of species-specific variations.
Pincer
The first method is the Pincer tactic, which is used by those species with the longest fangs, and is the method used by our own local SKiller, D. crocata. These guys run quickly up to a woodlouse, turn their “heads*” sideways and pince the woodlouse with their fangs. The upper fang doesn’t pierce the prey; it just provides leverage against the woodlouse’s armored back. The lower fang pierces the soft underside, enabling venom injection.
*Spiders don’t really have “heads” of course. What they pivot is their cephalothorax, one of the 2 body segments of a spider, the other being the abdomen.
Now this doesn’t always work right away; sometimes the woodlouse succeeds in rolling up in a ball first. When this happens different species try different tricks. Some will pick up the “ball” with their forelegs and turn it over and around repeatedly, searching for a gap between the plates into which they can work a fang. But others will simply sit and wait. After a short while- usually less than a minute- an undisturbed woodlouse will typically unroll, enabling another attack.
Extra Detail: Say what? How dumb is a woodlouse? The spider is sitting right there! Why does it unroll? The key is most likely lack of motion. Remember last Fall when we looked at compound eyes, I mentioned that while compound eyes are poorer than camera-style eyes for image-resolution, they’re great at detecting motion. A Woodlouse has very simple compound eyes, with only 15-50 ommatidia each, meaning that its image-resolution must totally suck. If a spider doesn’t move, a woodlouse can’t see it.
It gets even better- the species D. abdominalis gently taps a woodlouse with its front legs before an attack, which seems to somehow calm the creature and dissuade it from rolling up. It’s like a hypnotic vampire attack from a horror movie!
Extra Detail/Tangent: Speaking of horror movies, one of the rather yucky things you may already know about spiders in general is that they only eat liquid food, and so digest their food prior to consuming it, a task which accomplished by injecting their prey with digestive juices. For a while this bothered me, but upon further reflection I’ve come to admire it, in the same way I admire lightweight, low-impact, sleep-under-the-stars campers. Hear me out.
When you read various sources about spiders, you’ll often read something to the effect of, “Spiders can’t eat solid food…” making their habit of injecting digestive juices into their prey to liquefy it sound like a way of compensating for a handicap- the lack of an extensive internal digestive system. But when you think about it, it’s not a handicap, but an advantage.
Large carnivores like us and mountain lions* and wolves consume mainly vertebrate prey which we must eat from the outside-in, because the flesh is on the outside, and the bones on the inside. But spiders eat invertebrate prey which must be eaten from the inside-out, because the bones are on the outside. Now if your food is nicely contained in a hard, (more or less) watertight exoskeletal container, why not digest it right there, instead of growing, maintaining and lugging around a large, complicated, metabolic-intensive internal digestive system which is prone to various distress, discomfort, blockages, cancers, etc.? We unfortunately don’t have that luxury, because our meat isn’t nicely packaged in convenient containers (and also because we’re not strict carnivores) and so we lug around all this extra, complicated, problem-prone equipment. We’re like campers who drag those big-ass RV/motorhomes all over the place, while spiders are like lightweight, lie-down-on-the-ground-not-a-care-in-the-world-Excellent-Campers. Spiders are way cool.
*I finally stopped saying “cougar”. Just got tired of all the jokes. I thought the slang was dumb and kept hoping it would pass by, like ”Don’t go there…”, or “You go girl!…” but unfortunately it seems to be sticking around.
Fork
The second method is the Fork tactic, which is employed by Dysderids with basal chelicerae segments that are concave on the upward-facing/top side.
These spiders run up to the woodlouse quickly, grasp it up top with their forelegs, and stab upward from below with their up-turned fangs, piercing the soft underside with not one but both fangs. The concave upper basal surface helps to position the edge of the woodlouse’s dorsal armor on top of them.
This tactic only works if the spider attacks before the woodlouse rolls up.
Key
The third method is the so-called Key tactic, used by Dysderids with fangs that are thin, flat, and fairly elastic. In this method the spider attacks not the soft underside, but the heavily armored back of the rolled-up woodlouse, probing with a single fang until it is able to work it into a tiny gap between two of the armored plates, like a key into a lock.
All of these tactics correspond to the morphology of the mouthparts of the species in question, which brings us to prey preference, as not all Dysderid species eat woodlice all the time, or, in some cases, at all. The species can be broadly lumped into 3 categories. First is those species with un-modified chelicerae- not flat, not long, just “regular”. Many of these species ignore woodlice altogether (though they effectively hunt other invertebrates). At the other end of the spectrum are obligatory, or near-obligatory woodlice specialists, who eat woodlice and practically nothing else, ignoring other prey when offered in experiments.
And then in between these 2 extremes are species that effectively hunt woodlice, but happily hunt other prey as well. These “Flexibles” occupy a middle ecological ground, and at the top of the list of the Flexibles is, that’s right, SKiller/D. crocata. SKillers in laboratory experiments, while effective woodlouse hunters, did not show any preference for them over other prey, happily attacking anything small and slow enough for them to catch. Biological flexibility, or “ecological plasticity”, is a common characteristic of many of the world’s most successful colonizers, from pigeons and starlings to crabgrass and dandelions to paper wasps and rats*, and is likely one of the reasons why D. crocata, alone of the Dysderids, has conquered the rest of the world.
*I so need to do a post on rats.
Pretty cool story for a spider on a patio.
Note about sources: Special thanks to my friend and fellow nature-blogger KB for research assistance. Info about distribution of Dysdera species and the phylogeny and natural history of Dysderids in the Canary Islands came from this paper. Info on the woodlouse-hunting tactics and Dysderid chelicerae morphology came from this paper. Info on the eyes of woodlice came from Lander University’s Invertebrate Anatomy Online site. D. crocatafang-zoom photo inset came from bugguide.net.
Several days back, the Hunky Neighbors had us over one evening for dessert. The adults were inside chit-chatting, and the younger kids out front playing, when Bird Whisperer, who was hanging out by himself on the rear patio, called me out to check out a spider he’d found.
Tangent: Our circle* has 2 other families with kids the Twins’ age. But Bird Whisperer is the oldest kid on the circle by 2 years. His nearest same-age friends live at least a mile away, so during these neighborhood get-togethers, he by and large does his own thing. Which works out fine, because he’s a patient, good-natured and introspective little fellow, filling his time reading, playing make-believe and poking around at things like birds, and of course, spiders.
*By “circle” I mean the actual circle/cul-de-sac/dead end on which we live. I don’t mean circle as in “social circle”.
It was an interesting spider, and very unlike the typical Wolf, Triangulate Cobweb and occasional Black Widow I’ve found around house and garage, so I had BW keep it corralled while I sprinted next door for the camera. Orange body, almost hairless, I figured it would be easy to ID when we got back home, and it indeed it was. It’s Dysdera crocata, known as either the Woodlouse Spider, or, even better, Sowbug Killer.
Oftentimes in this project I’m forced to choose between competing common names when blogging about something or other. Usually I try to use either a) the name I knew already, or b) what seems to be the most commonly-used common name in the Western US. But whenever one of the candidate common names has the word “Killer” in it, that automatically beats out all other candidates. So Sowbug Killer it is, or SKiller for short.
It turns out that the SKiller has a really cool story. First a few basics. SKillers are nocturnal, running hunters. They don’t spin webs, but they do spin little silk nests or “cocoons”, located under rocks or logs or bark in which they pass away the daylight hours. Come nightfall they emerge and run around over patios and such hunting their favorite prey, that being- you guessed it- Woodlice (also called Sowbugs, but here I’m following rule “a”.)
So one of the first interesting things about SKillers is that they’re exotic. Dysdera is a genus of over 200 species, all of which are native to the Mediterranean region and the Atlantic Islands off the coast of North Africa. Of those 200+ species, 1- just 1- D. crocata- is cosmopolitan* in distribution. The distribution of Dysdera spiders, and how it came to be that just 1 species colonized the world, turns out to be way fascinating, but before I tell it, we really ought to spend a moment or two on their prey.
* I am embarrassed to admit that before I started this project, I didn’t realize that the word “cosmopolitan” could be applied to non-human creatures. But of course it can, as it means that something- a spider, a plant, a bird- can be found practically worldwide. I always assumed cosmopolitan simply meant a person who was multi-cultural, or somehow transcended traditional boundaries of culture and/or nationality. Either that or a scantily-clad female on a magazine cover at the supermarket check-out.
I’ve mentioned woodlice a couple of times in this blog; they’re so common it’s hard not to. When we last saw them was last November in my garage, where we left them on a somewhat uncertain note. Woodlice are crustaceans, like lobsters and crayfish, but they bear a remarkable physical resemblance to Pill Millipedes, which although not at all closely-related have evolved a remarkably convergent body form, complete with an independently-evolved ability to roll into a defensive ball, protecting their vulnerable undersides. And I left them admitting that while I suspected my garage denizens to be Woodlice and not Millipedes (based on the configuration of the exoskeletal plates toward the rear end), I wasn’t really sure.
Well now I am sure- they’re Woodlice, specifically Armadillidium vulgare, the Common Pill Woodlouse. Here’s how I know:
In this close-up photo of the underside of one, you can see that there is 1- and only 1- pair of legs per body segment. Millipedes have 2. And there are exactly 7 pairs or legs, as is always the case with Woodlice.
Tangent: The specimen for this Woodlouse photo was provided by Twin B, who is diligent, reliable and fearless when providing invertebrate specimens, with the one notable exception I have mentioned before- spiders. I swear, with any other bug- Woodlice, flies, Box Elder Bugs, beetles, ants, moths, whatever- she’s like this little Gandhi, always carefully handling them and then releasing them outside, never swatting or killing them. Only spiders freak her out.
A. vulgare is, like D. crocata, an exotic* in North America, native to Europe. It’s sort of as if predator and prey have chased each other around the world.
*When I started this project I already knew that many, many plants and birds around me were non-native. One of the surprises along the way has been how many bugs are exotics as well. Just in my garage Woodlice, Triangulate Cobweb Spiders and Paper Wasps have been 3 recent examples.
There are some other great things we can see in this shot. Toward the rear can see a number of whitish plates in the center between the 6th and 7th leg-pairs. These are pleopods, which are actually modified gills, which leads to probably the most interesting thing about Woodlice- They’re the only crustaceans* that have fully adapted to life on land. And though they’ve adapted well, they’ve done so differently than other invertebrates that emerged from water onto land, such as insects and spiders.
*Specifically, they’re Isopods, which are an order of crustaceans with 7 pairs of legs.
Woodlice never evolved the waterproof waxy cuticle that keeps things like insects and spiders from dehydrating, so drying out is a constants threat to which they’re adapted in several ways. Many of these ways are behavioral; Woodlice avoid direct sunlight and favor damp, moist places. Pleopods need to remain moist to function, as in gills the gas-exchange occurs across a wet surface. But they’ve also evolved a few tricks, including the ability to routinely withstand and fully recover from up to 30% dehydration. (Humans are generally dead by 15% dehydration.) More impressively, they can absorb water vapor directly from the surrounding air at humidity levels of greater than 87%. Hardly any other animals* can pull off this trick at less than 100% humidity.
*Ticks can.
But a number of Woodlice species, including A. vulgare, have also evolved additional “dry-land” lungs to augment respiration, and these, called the corpus alatum, are also clearly visible in the photo. The corpus altum is a system of pseudotrachea, so named because they are vaguely similar to trachea, which in insects deliver oxygen directly to tissues, but work a bit differently, delivering oxygen to the “blood” (or rather the Isopod version of it) which then carries it to tissues throughout the body.
Tangent: There’s something really cool to think about here. As large verterbrates, most of us have some knowledge of the whole fish-evolving-its-way-onto-land thing through the evolution of primitive “lungs” (probably from a modified swim bladder) and modified lobefins, and the eventual evolution of reptiles, from which things like mammals and birds came about.
But invertebrates- “bugs”- obviously worked their way onto land separately, and what’s interesting is that different groups of arthropods did so independently and came up with dramatically different ways of surviving on land. We’ve already looked at the radically different respiratory architectures of insects (trachea) and spiders (book lungs). Woodlice represent a third way of evolving a terrestrial respiratory system (pseudotrachea). This is one of the things that fascinates me about evolution, that nature comes up with so many different ways of solving the same problem. And yet in so many cases they end up- like Pill Millipedes and Woodlice, like Old & New World Vultures, like Old & New World Porcupines- amazingly similar things that came to their respective “thing-ness” via completely different paths.
When I thing about all of the examples of convergent evolution here on Earth, I sometimes figure that if life exists elsewhere in the universe, for sure it has pillbugs and vultures and porcupines. But then I think about trachea and book lungs, and I suspect I don’t have any idea what life elsewhere would be like…
Before leaving our Woodlouse friend, there’s something else about him we can tell from this photo. And that’s right, I said “him”, for this A. vulgare is male. Males have elongated, curving, backward-pointing first and second pleopod pairs, which guide the transfer of the sperm packet when mating, which he deposits at the base of the female’s pleopods while crawling across her back.
The entire underside of the Woodlouse is obviously soft and thin- translucent even- compared with the hard armor covering its top/backside. The soft exoskeleton provides flexibility for movement but represents a vulnerable area, which is why these guys roll up into a ball when threatened. The obvious challenge for anything that wants to eat a Woodlouse- say a SKiller for example- is how to get at the soft underside.
No real post today, total filler. But it’s fun filler, because it solves a year-old mystery.
A year ago I did a post about run-off in which I mentioned that Little Cottonwood Creek runs right outside my office. One day a kayaker showed up, and I included a couple of photos in the post, mentioning that I had no idea where he took out. Now I know.
Yesterday he showed up again as I as walking out of the building and I stopped and chatted with him. His name’s Dave, he’s very cool, and he lives about a mile downstream, right by Wheeler Farms. So he walks up to our office, pulling his kayak on a skate. Then he puts in, plays in the eddy, and kayaks home.
But kayaking home means not only that he goes under the overpass shown in this clip, but that he runs the creek through the covered viaduct that routes the creek over I-215. The guy kayaks over the Interstate!
Last week the run-off was even higher- the highest we’d ever seen it, and supposedly running at levels not seen since the early 1980’s. Dave says that to run the creek when the water is that high, a kayaker has to flip over as he approaches the viaduct (and a couple of other underpasses) and stay flipped over till emerging at the other end.
Note: I traveled for work last week, and tried to squeeze this post in while on the road, but couldn’t get it done till the weekend back home. So it’s a week behind, and the blooms I describe a bit dated, but it covers a couple of flowers I wanted to blog about out, so I’m getting it done anyway. Sorry for the time-lapse.
These next couple of weeks are my absolute favorite time of year. Most everything below 8,000 feet has melted out and is starting to bloom, and the final patches of snow are starting to disappear up at the 8,000 – 9,000 foot level. Wherever the snow gives way, life just explodes- shoots, leaves, flowers- it’s like there’s something new to see every time you walk outside.
And there’s just so much time to be outside now. The sky is already that soft pre-dawn royal blue when I walk out at 5:00AM for the paper. And when I crash at around 10:00PM it’s barely dark enough to see a star or two.
Tangent: This, BTW, is why I haven’t done an Astro-Post in so long. Because I cannot stay up late- or get up early- enough to see any stars. I had the best of intentions for a Hydra post, but I just get so darn sleepy around 10… The only things I’ve regularly been able to see this last week or so have been Venus when I go to bed and Jupiter when I go out for the paper.
Which is why- and yes, this whole little Ode to Spring is going somewhere- I feel it is such a fundamental sin to travel for work outside of Utah in June. And yet, last week, at the glorious peak-bloom of June, I found myself back on a plane to the Acid Swamp, for more employee training. It’s as if you went to the movies and spent 2 hours watching a film that was building up to some huge, plot-resolving showdown-climax, and you decided right then to get up and go to the bathroom. What? Don’t leave now! Cross your legs! Pee in a cup! But whatever you do, don’t step out now! But of course that’s exactly what I did last week…
Tangent: I’ve been holding off on doing a tangent about the exercise in sickly-sweet false sincerity and age-regression that is Corporate Employee Training. Too many coworkers read this blog. It’s just too risky. But I’ll share just a quick tidbit that made me think…
Nested Tangent: Actually, at this point I think I ought to distinguish between Generation 1 coworkers and Generation 2. Gen 1 coworkers are coworkers from my old, pre-acquisition company. Gen 2 coworkers are coworkers from the much larger acquiring company. Several Gen 1 coworkers read this blog. If you are a Gen 1er, I’d prefer that you not share the blog- or at least my identity- with any Gen 2 coworkers*.
*I don’t believe I have any Gen 2 coworker readers. If I’m mistaken, and you’re a Gen 2 reader, I’d appreciate your giving me a heads-up. (I’ll give you a sticker.)
On the flight out, I thought, “Oh dear god. Please don’t have them make us do another “team-building” exercise. I’m 46 years old. I graduated from college a quarter-century ago. I have a family, a house and 2 cars, a 401K and a 529. I am a grown-up. I don’t want to forge make-pretend bonds of trust and camaraderie with coworkers I’ll never see again from Columbus and Tulsa. I don’t want to sit in a circle and have us each “share with the group something no one knew about you before*…” For Christ’s sake, we’re coworkers, not lovers. I just want to take the class, learn the stuff, get the sign-off, and go home…”
*I’ve already shared in these types of exercises pretty much all the interesting things about me, namely a) my godfather was the guy who wrote Everything You Always Wanted to Know About Sex But Were Afraid To Ask, b) that I have walked away from 2 motorcycle accidents, a horse rolling over on top of me, and a bullet wound to the head, c) that I accepted an offer of an employment out of college with the CIA but never got the security clearance, d) that I used to be ½” taller, and e) that I can play the William Tell Overture on my face. I am totally running out of material.
Sure enough, on Day One, following Welcome and Introductions, our instructor had us break into pairs for an “ice-breaking” exercise. Which is kind of ironic, because all of the class attendees were salespeople, a decidedly “un-icy” group. If you were running a class full of less outgoing types- say particle physicists, chimney sweeps, or serial killers- then I could totally see the need for an “ice-breaking” exercise. But when you run a class full of salespeople, you don’t need to “break the ice”; you need to tell everyone to sit down and shut the hell up.
But as it turned out, our exercise actually got me thinking.. We had to share with our partner several things about ourselves, one of which was our first paying job, which for me was Paper Boy*. And that made me realize that 1) “Paper Boy” dates me. There are no Paper “Boys” nowadays and haven’t been for maybe 20(?) years. Eventually, maybe 50 years from now, the remaining Former Paper Boys will be like WWII veterans- there’ll be hardly any of us left. Maybe we’ll get together for reenactments, riding around on bikes at dawn and throwing papers on peoples’ steps, and the President will make speeches about us. And that 2) I have fond memories of getting up dawn to ride my bike around… which ironically is what I do pretty much all the time nowadays. Maybe I’m just a frustrated Paper Boy at heart.
*Technically I think it might have actually been babysitter, but I thought that sounded a bit girlie…
Before I flew out last week I finally rode Pinebrook. Even though the trails are at the same altitude as Glenwild/Flying Dog, they tend to be North-facing, and so take another couple of weeks to melt out. The trails were tacky, dust-free and smooth.
Video Note: The white blossoms on the small trees lining the trail are Serviceberry flowers.
The Groundsel, Larkspur and Ballhead Waterleaf(pic, above right) are all blooming here like they are on the other side of I-80 (Flying Dog/Glenwild) but so is much more. One of my favorite blooms in moist, shady spots in early June is Western Clematis (pics left & right). I blogged about this flower a couple of years ago, and as a reminder, one of the coolest things about it is that it’s a native climbing vine, which is pretty unusual in Utah*. Another neat thing about it is that its lavender “petals” are actually sepals; the true petals are the soft, white, almost translucent flimsy bits sheltered within.
*Poison Ivy is another, which I blogged about in this post. Man, it is like I have a post for everything.
New Flower!
Though most of the flowers were like old friends, I had a first-time sighting on the ride: Blue Violet, Viola adunca (pic left). This is the third violet species I’ve spotted in Utah. Last summer AW and I came acrossMountain Violet, Viola purpurea (pic below, right), growing at 9,000 feet in newly melted-out Aspen forest near Guardsman Pass, which I blogged about in this post (and which you can check out for some basic violet info.) Then late last July I spotted- but never got around to blogging about- Canada Violet,Viola Canadensis (pic below, left),at around 8,500 feet along the Mid-Mountain-Mill Creek connector trail, in deep, dark Spruce forest.
There’s a common thread across these 3 sightings: Violets grow low, way low, and are characterized by short herbaceous stems bearing just a few small leaves and the tiny florescence, only 3-5” off the ground. This means that in the Wasatch, violets only bloom either a) where there’s little or no underbrush- such as shady, acidic-soiled Spruce forests, or b) where there’s little or no underbrush yet, such as in new-melted out Aspen groves…
The Pinebrook you see in these helmet-cam videos is an open, early-season, nearly-bare Pinebrook. In the weeks ahead the underbrush- Ninebark, Chokecherry and more- will fill in, leaf out, and, in turn, bloom, creating the “aspen jungles” of July and August. Violets dodge the onslaught of the jungle, either by moving fast and early, or by hiding in the dark spots where the jungle can’t reach them.
Video Note: There’s a bonus in this one for local mtn bikers. If you ride Mid-Mountain between Canyons and Pinebrook, there’s a long boring down/up, depending on your direction- down if you're headed Southbound- of 32 very monotonous switchbacks. But there's a great, lightly-ridden and much better bypass option. In this video, moving Southbound, the first 3 turns in the first 40 seconds show how to access the bypass.
(Another) New Flower
There was another flower along the ride that I have spotted before- many, many times- but which falls into that so-common-I’m embarrassed-I-haven’t-blogged-about-it category. It’s this little guy, Lanceleaf Springbeauty, Claytonia lanceolata (pic below, left), another low-to-the-ground early bloomer.
There are 26 species of Claytonia, a genus belonging to Portulacaceae,the Purslane family. We haven’t looked at Portulacacea before, but it has an interesting family tree, and the long and the short of it is that Springbeauty- and other Portulacacea- are more closely-related to things like carnations, cacti and even tamarisk than they are to just about any other flower you’ll come across in the Wasatch. If you live in the Eastern US, you’ve likely spotted Lanceleaf Springbeauty’s (very similar) Eastern cousin, Eastern Springbeauty, Claytonia virginica. Springbeauty’s roots, which run laterally a few inches below the surface, are thick and edible.
Coinkidink
Wonderfully Coincidental Side Note: Although Springbeauty is the first Purslane family member we’ve looked at in this blog, it’s not the first for readers of SkiBikeJunkie’s blog, who coincidentally were exposed to another Claytonia species the week before last.
In a comment to SBJ’s recent lovely wildflower montage, I jumped in- show-off that I am- and ID’d all of his flowers- except one. That one exception, which I didn’t recognize at the time, is almost certainly one of 2 species, the first being Streambank Springbeauty, C. parviflora.
But the other possible species- and the one I’m really rooting for, as it’s one I’ve been hoping to spot- is Miner’s Leaf Lettuce, C. perfoliata, so named because 19th century miners supposedly munched on its Vitamin C-rich leaves to ward off scurvy. (SBJ: I need you to guide me to it this next week…)
But none of this is the really cool thing about Lanceleaf Springbeauty in the Wasatch. No, the really cool thing about C. lanceolata here is its polyploid races and their distribution.
I’ve blogged about polyploidy in plants several times (and you can read the basics here.) One of the early ploidy-related posts I did was about Creosote, which has distinct polyploid races. In the Chihuhuan Desert Creosote is diploid, with 2 sets of chromosomes, 13 from each parent, for a total of 26. In the Sonoran Desert, Creosote is tetraploid, with a total of 52 chromosomes. And in the Mojave (like around St. George and Vegas) it’s hexaploid, with six sets- or a total of 78- chromosomes. Well, it turns out that something roughly analogous seems to be the case with LL Springbeauty in the Wasatch.
From ~5,200 - 7,500 feet in the Wasatch, LL Springbeauties, like the ones I saw in Pinebrook, are overwhelmingly diploid, with 16 chromosomes, 8 from each parent. But up around 7,800 – 11,000+ feet they’re nearly all tetraploid, with 32 chromosomes. For whatever reason, the tetraploid race seems better able to grow and reproduce better in the colder, shorter-growing-season climate of the higher altitudes.
Between 7,000 – 8,000 feet, a third race is sometimes found, with 24 chromosomes, making them chromosomally triploid. It’s suspected that triploids, found in areas where the diploids and tetraploids overlap, may be the results of crosses between the two, receiving 8 chromosomes from one parent, and 16 from the other.
LL Springbeauty is our little local version of the Creosote polyploidy story, except that the races are all within a stone’s throw of one another, and separated not by distance, but by altitude.
Extra Detail: Though this may sound complicated, the ploidy situation with C. lanceolata in Northern Utah is actually really straightforward compared with the crazy chromosome counts for this same species found in nearby Colorado and Wyoming. LL Springbeauty there often has chromosome counts of 52 or higher, and many plants are aneuploid, having an odd number of chromosomes, like 37. When you read literature on the topic, various hypotheses are often suggested for how these came about.
For example, an LL Springbeauty with a chromosome count of 36 in Colorado could be the result of an previous triploid (24 chromosomes) hybrid cross, whose progeny subsequently doubled in a subsequent ploidy event to 48 chromosomes. If the hexaploid then backcrossed with a triploid, you could then wind up with a 36 chromosome plant, having received 24 from the hexaploid and 12 from the triploid parent. The possibilities are both endless and conjectural, but it gives you a feel for all the crazy evolutionary paths polyploidy opens up for plants.
Anyway, like I said earlier, it’s a sin if you have to travel away from the Wasatch these next couple of weeks. But you know what’s an even worse sin during this same time? Spending your days down in the valley and not finding a reason to get up into the mountains or foothills, for at least 30 minutes or so, every day. The best show of the year is playing right now, and you don’t want to miss a single episode.
