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: 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!
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: 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: 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,
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: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: 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!
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: 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: 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: No reason to write a post about that!
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: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: 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!
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):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'.
The first question I ask myself when I see a small orange butterfly in the Skipper family is "What reason does it give me to think this is anything other than a Fiery Skipper?" Most of the time, the answer is none. The reason is that this butterfly is a well-adapted generalist that thrives on a very common plant beloved (rightly or wrongly) by homeowners across the country: grass.1 This makes it a very common butterfly, with a wide distribution: it occurs from coast to coast in the southern part of the country (one of the first documented times I saw one was on a visit to the Page Museum, aka the La Brea tar pits in Los Angeles), and from the midwest to the east coast it occurs relatively far north as well, even reaching the Great Lakes. Skippers are a large group of smallish butterflies with large bodies relative to their wing size (when perched, the tail end of the abdomen usually sticks out past the wings, whereas most other butterflies have wings, rather than body, tailmost). They often perch with their hindwings held low and their forewings held at a forty-five degree angle, reminding me of the tails of a jet fighter. (This perching posture differentiates most grass skippers from another group of skippers called the "spreadwing" skippers like Horace's Duskywing, which perch with their wings, well, "spread.") There are three small orange skippers in my area that I need to consider whenever I see one: Fiery (by far the most common and widespread, spotted), Whirlabout (less common, also spotted), and Sachem (more common north of us, white spots instead of black). Among these three, the Fiery and the Whirlabout are the most confusing, as they have very similar dark spots on their orange wings. The best ID mark I know is easier to spot in photographs than in the field, at least for me: on Fiery, the trailing edge of both the forewing AND the hindwing are scalloped, while on Whirlabout, ONLY the forewing is scalloped; the hindwing has a "smooth" border. Despite their close visual resemblance, though, Fiery and Whirlabout skippers are not very closely related. The Fiery is the only member of its genus in North America; all of its close cousins are in South America (15 to 20 species in total). Whirlabout, on the other hand, is one of many "polite" skippers, so called not because they say please and thank you but because they appear "polished" or "refined" (from the latin politus) compared to most grass skippers. Hylephila phileus translates to "woods-loving," which is about as far from an accurate description as it's possible to get in describing this urban (or urbane) lawnlover; it seems to delight in sunny open spaces rather than close dark forests. Here are a couple of recent pictures of this lovely little butterfly: References Cech, R. and G. Tudor. 2005. Butterflies of the East Coast: an observing guide. Princeton, NJ: Princeton University Press. Glassberg, J. 2012. A Swift guide to butterflies of North America. Sunstreak.
It doesn't take long to "survey" the yard when you're a backyard naturalist. A few minutes in the morning, as long as you actually get out and do it, can have some interesting results. This morning, as I was grinding through the normal workaday toil, I decided I simply hadn't been outside enough for the day. So I took my camera and wandered around the front and back yards for about five minutes. And in those five minutes I found a butterfly that I'd never seen before! It's another hairstreak, like the very common Mallow and the much less common Martial, but this one is a relatively recent newcomer to Florida, having been definitively established only since the mid-70s: Fulvous Hairstreak. William Chapman Hewitson (1874) bestowed the species name (angelia); said species name is almost certainly behind one of its common names, Angelic Hairstreak. While it's always nice to see new butterflies, especially ones that are rather strikingly handsome, this one brings up some decidedly mixed feelings. Its most common hostplant is the non-native invasive tree species Brazilian Pepper (Schinus terebinthifolius—often written as S. terebinthifolia because, Latin). The plant itself is fairly pretty when it's in fruit, as the huge clusters of tiny red berries against the dark green foliage give it a festive appearance. It was first imported as an ornamental in the 90s—the 1890s1—and, because it thrives in this environment, became very popular. A couple of common names from back in the 50s when it first found widespread cultivation as an ornamental in south Florida were "Florida Holly" and "Christmas Berry." And on the surface, what's not to love? It's fairly pretty, particularly when trimmed up as a specimen rather than allowed to grow to its natural form (basically, a 30-foot sprawling globe), it grows and propagates easily, and it has high wildlife value—the birds love the berries (which allows it to spread easily via seed transport, aka the poop train). But dig a little deeper and you discover that perhaps this plant isn't so nice:Like most hairstreaks, it's a small butterfly, with a wingspan less than one inch. And, like many hairstreaks, it's fairly pretty. Perhaps the combination of those two traits was the reason
- It's a member of the cashew family (Anacardiaceae) and, like its cousins in that family (think poison oak, poison ivy, poison sumac), is a skin irritant. So just trimming it up to look nice can cause sensitive types (like me) to break out into a painful rash.
- It also produces allelopaths, chemical substances that inhibit the growth of other plants in its area. Like a planet, it clears its own orbit.
- Its so easy to grow that it currently dominates over 700,000 acres in Florida, making it the number one invasive plant species in the state.
Given the abundance of Brazilian Peppers in Florida, it is surprising that the Fulvous hairstreak is not one of the state's most prevalent butterflies.It isn't though. This sighting was my first in the fifteen years I've lived in Florida. As Cech and Tudor continue:
While it does often occur in swarming local colonies, the Fulvous is not an everyday sight throughout its range. It poses no visible threat to its hostplant's viability, based on it apparently modest appetite as an herbivore.More's the pity, some might say. Sometimes I don't know whether to admire or curse Nature's whimsy. Beautiful native plants like the Fiddlewood (Citharexlyum fruticosum) get stripped down to twigs by the fiddlewood roller (Epicorsia oedipodalis, a fairly ugly little caterpillar that grows into an even uglier moth), yet the beautiful butterfly that feeds on Brazilian Pepper doesn't even put a dent in that noxious weed. Still, I suppose it's a good thing that I don't see too many of these little butterflies in my yard; it means there aren't too many Brazilian Peppers in my neighborhood. There's also another way of looking at it: there are reports from Cuba of this butterfly feeding on a diverse genus of wildflowers, Salvia, of which I have several different varieties in both front and back yards. If the south Florida hairstreaks feed on Salvia as well, I won't mind having them around at all! References Cech, R. and G. Tudor. 2005. Butterflies of the East Coast: an observing guide. Princeton, NJ: Princeton University Press. Glassberg, J. 2012. A Swift guide to butterflies of North America. Sunstreak.
I've been focused on other things so far this year, so I haven't been working out in the garden nearly as much. And without being outside as much, I haven't encountered nearly as many animals as I normally do. This weekend, though, I was able to get out in the back yard for a little while, and I found a few insects flying around. One was a moth that I'd never seen before, Slosson's metalmark (Tortyra slossonia). Very flashy, quite small; it was walking around on a typically huge elderberry flower (technically an inflorescence, or collection of flowers) that was about six inches diameter. It was fairly quiescent, which normally makes for a good photographic subject, but the wind was blowing the plant around fairly frequently, making focusing a challenge. Unfortunately, right as the wind started to settle, the moth was flushed by an approaching butterfly, and I never saw it again. Here's the best image I was able to obtain: a brief write-up on the "little brown jobs" common to birding and butterflying.The plant was in shade, so I had to use flash, and the tone of the image is a bit muted compared to the brilliant metallic orange-red of the wing stripes, but the "face" of this little beast is so interesting I had to show a picture of it somehow. I can't wait to meet this guy again and get some more shots! And over on the sunny side of the house, I saw a pair of male little brown butterflies giving each other problems. Neither one wanted to allow the other a place to perch and bask and (perhaps) espy a passing female. But every now and then one would alight for a few seconds and allow a frame or two to be squeezed off. Here's one that worked, well enough to ID the guy as a Horace's Duskywing (Erynnis horatius): If you're curious, you can see a female E. horatius that I found a few years ago in the "courtyard"; that experience prompted
I've already mentioned how glad I've been to have the Bahama Sennas I put in last spring (Senna mexicana var. chapmanii). They've attracted my "everyday" sulphur, Cloudless (Phoebis sennae), a nice Sleepy Orange (Eurema nicippe), and now a new butterfly for the yard (one of the only new insects discovered in this windy, windy November), the Orange-barred Sulphur (Phoebis philea):As soon as I saw it, I knew it was a different butterfly than any of the ones I'd seen before. Its size alone made it stand out; this is Florida's largest sulphur butterfly, even larger than the appropriately named Giant Orange Sulphur (P. agarithe). The cloudless sulphurs I see every day, while not exactly shrimpy, look small compared to this hulking giant. The color also made it stand out. The entire underside (that is, what's visible when it has its wings closed) was "rusty" orange, and the orange was particularly prominent when it was flying. I managed to capture a moderately nonhorrible image of the hindwing orange area, although it's nothing to write
home an entire blog post about:
The orange at the base of the female's hindwing is not the "bar" referred to in the name, though. The orange-barred part of the name comes from the male, which has a thick orange "bar" on the forewing (In case you didn't know, in describing an animal, stripes run vertically, while bars run horizontally.):
According to almost all of my books, the orange-barred sulphur colonized Florida from the West Indies in the late 1920s.1 According to Cech and Tudor, it is less migratory than our other sulphurs (Cloudless being the "typical"—or perhaps extreme, rather than typical—migratory sulphur, occurring over a wide range at various times of the year.)
Like most sulphurs, its larval host plant family (what the caterpillars eat) is the sennas in the genus Cassia (as opposed to the sennas in the genus Senna—plants are awesome!).
The caterpillars of the Orange-barred are highly variable green or yellow, but no matter what basal color they have, they have bold markings that make them quite a bit more colorful than the green-with-a-yellow-racing-stripe Cloudless cats:
However, I have yet to find one on my property; all of the candidate caterpillars I've found have turned out to be early instar cloudless sulphurs; as they grow, they get greener and greener.
Caterpillars of all the sulphurs appear to prefer to eat the flowers, although the leaves will do when there are no flowers present. (And there are rarely flowers present, since there are so many generations of caterpillars, and they all prefer the blossoms, or if those are absent, the buds.)
After leading my annual Audubon Society of the Everglades birding field trip to Green Cay this November 28, I made my annual stop at Native Choice Nursery. They weren't yet open for the day, but they'd left out exactly what I wanted: Climbing Aster (Aster carolinianus). I paid in the main office (a bargain at $5 each) and put them in the ground in the morning, watered them in, and left for the beach. They're basically a wetland plant in the wild, but one of my books tells me that they're pretty adaptable, so I put them in along a fence (to give them something to climb) next to another climbing vine-type plant, Coral Honeysuckle (Lonicera sempervirens), which is another plant that starts to sulk when I neglect to hit it with the hose every few days. Here's a photo from Craig Huegel's excellent blog, hawthornhillwildflowers.blogspot.com (he's also written several recent books on various types of Florida native plants): Here's hoping mine do half as well. The more photogenic of the two I picked up is below: Neither of the plants I bought had lovely blooms on them. I did this deliberately, because those typically drop off very soon after planting, leaving me disappointed. And the blooming season of these plants is very late, so I'm hoping that by putting it next to the summer-blooming Coral Honeysuckle I'll have blooms even in the dead of "winter" here. Plus, asters are the larval host plant family for the Pearl Crescent, so I'm hoping this planting will take off and provide some food for those lovely little guys.