Giant Trees

On a recent trip to New York City, the boys and I wandered through the American Museum of Natural History, inspecting the dinosaurs on the fourth floor, the Hayden planetarium over on the other side of the building, and a few of the points in between. One of the sights I found most interesting was the huge cross section of a giant old sequoia (Sequoiadendron giganteum) in their "ecosystem" section:

The Mark Twain cross section at the AMNH. Photo by Matthew G. Bisanz from Wikimedia commons.

Unfortunately, because I don't know how to manage my iPhone storage, I was unable to take a picture myself (hooray, 16GB of "storage"!), so I had to use the one above from Wikipedia. It doesn't really have the impact that the huge piece of wood had on me. Here's an image from a National Geographic archive that really gets across the idea of how big this thing is:

Loggers with the freshly felled Mark Twain tree, 1892.

I was so impressed by this piece of wood that when it came time to plan our annual pilgrimage to California, we decided to visit the much-more-crowded southern Sierra instead of the eastern side, where we normally go. For the past several years, we've been going to the park at the Ancient Bristlecone Pine Forest. Those trees, growing at 10,000+ feet of elevation, are much smaller than the giant sequoias but also much older. Some of them are over 5,000 years old. But they don't make as much of an impression on the younger crowd as they do on me. So this year, it's time to visit the real giants. And when we do, we won't forget to walk the Big Stump Trail! Interesting note about the wood of these giant trees: at the same time, it's soft, brittle, and highly resistant to rot.

A common lichen of Florida scrub: Powder-puff deer lichen

When walking through the sandy scrubby areas at my two favorite natural areas here in Boca Raton (Yamato Scrub and Pondhawk), if I keep my eyes on the ground I can usually rely on encountering a fine group of reindeer lichen like this one:

Reindeer lichen (Cladonia evansii), Yamato Scrub, January 19, 2017.

But just what the heck are reindeer lichen? While I've known about this species (we'll keep it simple and just call the symbiont a species) for at least a decade now (first encountered in my field classes from the Florida Master Naturalist Program), I'd never done much research on it. After encountering this beautiful reindeer lichen at Yamato Scrub this past January, though, I decided to correct this deficiency in my education. About the only bit of knowledge I have about lichens is that they are a symbiotic association of (usually) a fungus and an alga. So, yes, when a fungus and an alga take a lichen to one another, something wonderful happens. [crickets chirping] However, when I began reading about lichens, I soon realized why I'd not put much effort into it before: the literature devoted to them is for specialists indeed! So, after quite a bit of reading, here's what I've found. The typical association of the organisms found in lichens is a fungus (which provides the structure or body of the lichen) and an alga (which provides the color). In technical terms, when found in lichens, the fungi are mycobionts and the algae are photobionts. Fungi derive all their nutrients from their substrate, while algae are capable of deriving energy directly from sunlight (through photosynthesis). The association works quite well, although the resulting organism is rather pollution-intolerant. Lichens are thus indicators of good air quality. (Hmm... Corals are also symbiotic organisms, and their fragile nature serves to indicate the health of marine waters. Maybe there's something to this ecosystem idea.) In any case, one of the things that makes lichens interesting is that the different species are linked together by their mode of nutrition, not their ancestry. Apparently, it's customary to name the lichen by the taxonomic name of the fungal part, ignoring the alga's contribution to the affair. Most people who have noticed lichens have probably seen them as spots or flakes of color on tree trunks or on rock surfaces:

Lichen on cabbage palm. Yamato Scrub, January 25, 2017.

Some lichens, though, appear to grow directly on the soil. And such is the case with Cladonia evansii, the powder-puff deer lichen. Here, for example, is the brief description of the genus to which this species belongs in the most recent taxonomic work I could find ("Field oriented keys to the Florida lichens," by Roger Rosentreter, Ann M. DeBolt, & Barry Kaminsky). I've highlighted in red the terms and concepts I'd never seen before in my life (notes are from various sources, chiefly here):
Description: Consisting of two parts, squamulose1 primary thallus,2 and an erect fruticose structure called podetia.3 Squamules small to medium. Podetia small to large. Pale greenish- gray to white to yellowish upper surface. Apothecia4 or soredia5 present. Never isidiate.6 Apothecia brown or red or tan. Spot tests7 various. Unique features: Sometimes intricately webbed as in C. evansii.
So you see, it's as simple as that. Fortunately, Green Deane over at has a good write-up of C. evansii here, including the various ways people have prepared it for eating and drinking, in case you need a break from the technical jargon (I know I do!). The U.S. Forest Service has a very long page devoted to the Cladonia group of lichens, although they don't include the southern-dwelling C. evansii in the list (they focus on its northern cousin, C. rangiferina). What they describe, though, helps me wrap my head around the anatomy of the lichens in this group.  From their write-up of Cladonia:
The lichen body, or thallus, is a composite structure of fungal and green algal cells. The primary reindeer lichen thallus is prostrate and squamulose (comprised of scaly, flaky, rounded pieces). The secondary thallus (podetium) is more conspicuous, being upright and fruticose. Fruticose forms are three-dimensional and have been described as shrubby and/or stringy. Podetia are hollow, highly branched, and capable of trapping wind-blown algae. They grow upward at the tip and die back at the base, similarly to sphagnum and other mosses. The spore-producing fungal bodies (apothecia) are produced at the tips of the podetia.
Anyway, what we need to know here is that the puffy part of the powder-puff deer lichen is the secondary thallus or podetium. It's the rounded bit that forms the powderpuff part of the organism. The primary thallus is the horizontally growing inconspicuous bit. Other lichens have other growth forms: folicose (leaf-like, as in the lichen on the cabbage palm near the top of this post); fruticose (shrubby), like the one we're talking about here; and crustose (crusty). Here's a close-up of one of the clumps where you can get a better view of the podetia, so you can see how they grow in an "intricate web" as noted by Rosentreter and colleagues:

Reindeer lichen (Cladonia evansii), Yamato Scrub, January 19, 2017.

There's a related species of lichen here in Florida, Cladonia subtenuis, that looks very similar, but the tips of the fruticose bits are less compact. A third species, C. perforata, also exists here and is endangered. It's restricted to the high, well-drained sands of rosemary scrub in Florida; I suspect it exists on some sites here in southern Palm Beach County, but I haven't found it yet—the closest known site is Jupiter Ridge Natural Area. According to an information page from the Archbold Biological Station, "C. perforata was the first species of lichen to ever become federally listed as an endangered in the United States. C. perforata differs developmentally from other fruticose lichens, by having its branches derived from spore-producing structures called apothecia, rather than from the primary body (USFWS 1999)." Lichens tend to grow on trees or rocks or in areas that are, at least seasonally, so hot, sterile, dry, or otherwise inhospitable that nothing else can make a go of it. In polar and subpolar areas, they can even comprise the dominant autotroph (self-feeding organism, usually translates as "plant," although only the algal partner in a lichen can be considered a plant in any strict sense). In this case, they actually grow on the sand. Or, actually, on a soil crust. What's a soil crust? Well, my friend, that is a deep rabbit hole indeed. If you're going to go down there, here is a description from the Archbold Biological Station's website (emphasis added):
Biological soil crusts. In drier regions of the world, soil microorganisms form what are known as biological soil crusts. Because of their hidden nature, these crusts have been termed cryptogamic, cryptobiotic and microbiotic. Crusts are created when soil organisms cause the uppermost layer of soil to solidify into a single, cohesive layer. The "glue" that holds the soil together is made up of the living organisms themselves together with the sticky substances they excrete and leave behind as they move through the dry soil. Biological soil crusts are a well-known feature of deserts in the southwestern United States and have only recently been recognized in the southeast. Crusts in Florida scrub are unique because they occur in a wet climate where dry conditions are caused by rapid drainage of water through sandy soils.  
See how far a simple nature walk can take you? I'll have to read a lot more about soil crusts before I can do justice to them here.

Christmas Eve birding in Texas

The family went west for Christmas this year, but only halfway. Spent the holiday just east of Dallas with family. Here are a few birds from Christmas Eve at the lake house and the farm:  

Flower spiders: Thomisidae

There are many genera of crab spiders (also known as flower spiders) in the family Thomisidae. One of the more common in my yard is (I think) in the genus Mecaphesa (but here's a good illustration of why I'm not positive about the ID). Like most crab spiders, these have a very variable appearance. In fact, they are able to vary their appearance to match the background against which they appear; it takes a bit of processing to get them to show up well when they're photographed in situ. I've written about these spiders before, but I saw one the other day and happened to have my camera with me, so I thought I'd at least take a picture:
Crab spider. Boca Raton, FL, September 29, 2016.

Thomisid (crab) spider. Boca Raton, FL, September 29, 2016.

As you can infer from the photo, they're quite small; the dune sunflower that it's perched on is only a couple of inches across. Not a threat to humans, although it might provoke startlement and wonder from any who happen to notice the little feller. However, when we zoom in on their scale, they start to look a bit more daunting:
Thomisid spider, close-up. Boca Raton, FL, September 29, 2016.

Thomisid (crab) spider, close-up. Boca Raton, FL, September 29, 2016.

As you can see, their front two pairs of legs are MUCH longer than the middle or hind pair. These ambush predators rely on those long front legs to seize their prey rapidly, then they use their chelicerae (fangs) to inject venom to finish them off. According to the University of Kentucky web site about crab spiders,
Scientists think that the venom of certain crab spiders is more potent than that of most other spiders: this allows crab spiders to quickly paralyze the large and tough bees that often visit flowers.  However, crab spider venom is not known to be especially dangerous to humans.
In case you're wondering, the not "especially dangerous to humans" doesn't mean being bitten wouldn't hurt. It just means that you'll probably feel, at most, an "ouch!" and some slight muscle cramping (to paraphrase Rod Crawford's description of the typical response to Tarantula bites). This bears remembering. We live in such a sanitized world, so far removed from an everyday experience of nature, that any reminder of it (lizards, snakes, spiders), or even the possibility of slight discomfort caused by it, sends shudders of revulsion down our spines. Like any wild animal, spiders should be treated with caution and as much knowledge as we can bring to bear on them. The more we know about them, the less frightened of them we need to be. If you're a caterpillar, on the other hand, go ahead and be frightened. If you're not wary, you are in for a rough time, as this "orange dog" (Giant Swallowtail cat) found out a couple of years ago:

Know before you go! Disguises and chemical defenses and living on a spiny plant only take you so far in life...

Etymology It's entirely plausible that the name of this family of spiders derives from the Greek word thôminx, "string." The suffix -idae is the typical New Latin suffix appended to the name of any organism to indicate that it is belongs to that taxon. (For example, gulls are "larids," meaning they're in the family Laridae.) However, the Century Dictionary, my go-to dictionary for etymology, gives a slightly more interesting derivation from its definition of Thomisus (the original name of a genus of this family): whip, scourge! screen-shot-2016-09-30-at-10-52-43-am

Dragonfly and focus

One of the challenges of insect photography is depth of field. The focal plane of any camera is flat. Insects are three dimensional. To represent a three-dimensional object in two dimensions requires considerable ingenuity on the part of a lens designer, and considerable work on the part of the photographer. One solution is to take multiple images and stack them, focusing on different parts of the insect in each frame. Here's an example of a Blue Dasher, where I was able to get two images with sufficient alignment and sufficiently different focal areas that the resulting image gets most of the bug in sharp focus. Unfortunately, I didn't get a midrange focus, so the tail of the creature is sharp, as are the eyes, but there's an area of soft focus halfway down the back:
Blue Dasher (Pachydiplax longipennis). Boca Raton, FL, October 9, 2016

Blue Dasher (Pachydiplax longipennis). Boca Raton, FL, October 9, 2016. Put your cursor over the image (or click here) to see the labels.

Still, it's a much better image than a single-frame capture would allow. I use a many-years-old version of Photoshop (CS4), but I imagine the process is similar in almost any photo-processing software. Step one: take a few pictures at different focus points:
Blue Dasher (Pachydiplax longipennis). Boca Raton, FL, October 9, 2016

Blue Dasher (Pachydiplax longipennis). Focus is on the head. Boca Raton, FL, October 9, 2016. Put your cursor over the image (or click here) to see the labels.

Blue Dasher (Pachydiplax longipennis). Boca Raton, FL, October 9, 2016

Blue Dasher (Pachydiplax longipennis). Boca Raton, FL, October 9, 2016. Focus is on the tail. Put your cursor over the image (or click here) to see the labels.

Step two: align the images. In Photoshop, this is done by copy-pasting one image onto the other, selecting both layers, then choosing Edit-->Auto-align layers. As long as the previous step (the shooting of the images in the field) was a success, the images should be fairly roughly aligned already. In this case, the software can align them pretty well. I haven't yet figured out how to rescue a poorly aligned set of images, but it might be possible to place them manually with good precision. Step three: stack the images. In Photoshop, choose Edit-->Auto-blend layers. Here again, as long as your previous step (the auto-align) was reasonably successful, the stack will be as well. Of course, if your subject has moved slightly, turning its head or shifting a wing, the resulting stacked image will have "ghosts" in it and will have to be discarded. Step four: save as one image (not a layered file), then you can adjust the colors and highlights, etc., as you normally would. (If you're clever, you might have adjusted the images before aligning and stacking, but I'm rarely that clever. Plus, if you have 5 or 6 images to blend, that's a lot of processing that I'd prefer to do in one step on the final, stacked image.) And that's "all" there is to it!

Caterpillar: Orange-barred Sulphur

Last fall I was excited to find a couple of beautiful yellow and orange butterflies (Orange-barred Sulphurs) flying around the Bahama Senna shrubs in the front yard. Search as I might, though, I never did find a caterpillar. This fall I've seen them flying on several occasions, but they've never settled down while I've had my camera with me. (Seriously, I've never seen so much fluttering and so little landing.) Even though I haven't been able to get a photo of an adult, I have finally found a caterpillar, so I guess things balance out. I was cleaning up the yard and taking down the shutters the morning after Hurricane Matthew passed by, staying politely out to sea but giving us all a healthy scare, when I discovered this bright yellow caterpillar on one of the shrubs:
Orange-barred Sulphur (Phoebis philea). Boca Raton, FL, October 7, 2016.

Orange-barred Sulphur (Phoebis philea). Boca Raton, FL, October 7, 2016.

Calloo callay! This little guy brought a little brightness to an otherwise drab gray day.

Dewdrop spiders: kleptoparasites

A few months ago, I joined a Facebook group called Florida Entomology. It's nice to see so many different pictures of insects and spiders and whatnot from around the state. And several of the people who post there are incredible photographers. One recent post caught my eye, because it captured the incredible beauty of a tiny spider that I see relatively frequently in my yard: a kleptoparasitic (food-stealing) spider in the complex Argyrodes/Faiditus/Neospintharus/Rhomphaea. It was particularly interesting to me because just about 10 days earlier, I'd gotten my own first acceptable image of a dewdrop spider from my yard:
Dewdrop spider, sedis incertae. Presumably Argyrodes/Faiditus/Neospintharus/Rhomphaea. Boca Raton, FL, September 18. 2016.

Dewdrop spider, presumably Argyrodes/Faiditus/Neospintharus/Rhomphaea. Boca Raton, FL, September 18, 2016.

Just how small is it? Well, I have a particularly fine macro lens on my camera (this is my DSLR, not my phone), and I was about as close to the spider as I could get and still have it in focus (less than 20 inches). That means the image scale is as large as it can possibly be. If you click the image above, you'll get a file 1496 pixels wide. It makes it look huge. It's not. If that spider were next to a bee's head, it would fit on the eyes. The one from Steve Long's image (the Facebook post I referenced at the beginning of this post) is described as "one-third the size of a grain of rice." The largest ones I've seen are no bigger than their namesake:1 dewdrops. Spiders in this group live a particularly daring lifestyle: they live in the webs of larger spiders, eating the prey that its host doesn't want or isn't fast enough to get or vigilant enough in guarding. Marhsall and Edwards provide a good description of its behavior in Florida's Fabulous Spiders:
This species [Argyrodes nephilae] enjoys the very great advantage of not having to produce or maintain its own web. It actually avoids the main web of the host spider, preferring to hang out on the frame and barrier web strands. Here it waits until wrapped prey is unattended by the host spider. Then it stealthily sneaks up to the prey, dragging a line behind it which is attached to the barrier web line. Once it attaches its own line, it cuts the thread from which the prey hangs. The prey then swings out into the barrier web. If the Argyrodes has done its job well, the host spider will never know it has been robbed. But if the Argyrodes nephilae makes a mistake, the bigger spider will come charging over to reclaim its prize.
Etymology The spider discussed above specializes in living in the webs of one of our largest orbweavers, Nephila clavipes, about which I'm astonished to discover I've not written before on this site, except for in asides on other posts. I'll be sure to rectify that soon. In any case, that large spider, I presume, is where the specific epithet (nephilae) of its tiny kleptoparasite comes from. The genus name, Argyrodes, means "silvery." Speaking of silvery spiders, it's worth pointing out that members of this silvery dewdrop spider group don't live just with the yellow-silk orbweaver. They can also be found in the webs of the more common (in my yard) large orbweaver, the Silver Argiope (Argiope argentata), about which I've written in the past. Here is a shot taken last year that shows both species, so you can get an idea of the enormous size disparity between them:
Argyrodes sp. Boca Raton, FL, September 10, 2015.

Argyrodes sp. Boca Raton, FL, September 10, 2015.

The image above also shows why I haven't written about these little guys before: same lens, same photographer, different luck capturing an image of this little one. Here's a crop from the above photo showing just the argyrid:
Argyrodes sp. Boca Raton, Fl, September 10, 2015.

Argyrodes sp. Boca Raton, Fl, September 10, 2015.

No reason to write a post about that!

Butterflies and Caterpillars in the Garden: Happy Birthday to me!

This morning was nice and calm and I decided to wander around and see what I could find in the garden. Found a few large Atala caterpillars munching on my coontie out back. They're very hard to take a good photo of, because depth of field is such a problem. Coontie are low-growing plants, so it's difficult to maneuver a tripod into position, so the "traditional" digital answer to this problem (aligning and stacking multiple exposures taken with slightly different focus points) is much harder to achieve. So the best I've been able to do is hold as still as possible, try to align the axes of the lens with those of the subject, and hope for the best. Here's a passable image, probably the best I've managed despite having the photo op literally 15 feet from my back door whenever I feel like it:
Atala Blue (Eumaeus atala). Boca Raton, FL, September 29, 2016.

Atala Blue (Eumaeus atala). Boca Raton, FL, September 29, 2016.

After I was done frustrating myself with this subject in the back yard, I wandered around to the font, where I found this lovely Gulf Fritillary butterfly resting on the Bahama Senna:
Gulf Fritillary (Agraulis vanillae). Boca Raton, FL, September 29, 2016.

Gulf Fritillary (Agraulis vanillae). Boca Raton, FL, September 29, 2016.

Unlike the ones flying up high in the passionvine out back, this one was very still. I suspect it was freshly emerged and still drying its wings; they're not normally this quiescent in the bright morning sunlight. The native plant society might not think too much of my garden, but the native insects appear to enjoy it anyway!

Dainty Sulphur puts the butter in butterfly

May is the month the butterflies in my yard really get going. It's not hard to see why many people speculate that there's a link between the little yellow butterflies in the sulphur family and the word butter-fly itself. Here's a buttery yellow Dainty Sulphur (Nathalis iole) ovipositing on its preferred plant, Spanish Needles (Bidens pilosa):
Dainty Sulphur (Nathalis iole). Boca Raton, FL, May 10, 2016.

Dainty Sulphur (Nathalis iole). Boca Raton, FL, May 10, 2016.

Yes, it looks kind of like it's actually depositing an ant, but it isn't. It's laying an egg! And now that the rainy season appears to have kicked in, I'm expecting a lot more insect life to come a-visitin'.
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