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!

Step into my parlor…

...said the spider to the lady beetle. And yet, nothing happened. This morning before work I went out and, as usual, was taking pictures of whatever I could find in the yard. I found this lovely Southern Sprite damselfly (first of the season):
Southern Sprite (Nehalennia integricollis). Boca Raton, FL, May 8, 2015

Southern Sprite (Nehalennia integricollis). Boca Raton, FL, May 8, 2015

It's always a pleasure to see these relatively rare damselflies. (Odd, too, how abundance is so tied to locale: Everglades Spite (N. pallidula) is considered very rare, while Southern Sprite isn't, and yet I get dozens and dozens of the former over several months and very very few of the latter. I guess being near the Everglades is conducive to the occurrence of Everglades Sprite? While most people across the range of these insects are not near the glades...) When I was finished with the sprite's photo session I wandered over to the patch of dune sunflower I have growing along the drive. I noticed one flower had two petals sort of curved upward toward each other, indicating, most likely, the presence of a hunting spider. (That is, a spider that hunts without using a web.) It had tied the petals together with a strand of silk; you can see them curling up toward the camera in the photo below:
Thomisid spider waiting for breakfast. Boca Raton, FL, May 8, 2015.

Thomisid spider waiting for breakfast. Boca Raton, FL, May 8, 2015.

Thomisid spiders are commonly known as "crab spiders" (not to be confused with Gasteracantha cancriformis, commonly known in south Florida as a "crab spider," although most naturalists call it the spiny-backed orbweaver to avoid confusing it with the "true" crab spiders like the one above). The true crab spiders are so called because their front pairs of legs are drastically elongated, much like the pincers of a crab. It's one of the largest spider families, with over 2,000 species worldwide. There are at least 130 species in 9 genera in the United States, so identification to species level is left to the true spider experts, the araneologists (as distinct from the arachnidologists, who study arachnids in general, which includes arthropods from other orders such as scorpions, mites, ticks, and chiggers, in addition to the Daddy Longlegs, which aren't true spiders at all). While I was taking pictures of this unusual flower-trapping arrangement (normally I see the petals of the flowers curled down, rather than up), I noticed a wee little lady beetle about to become breakfast:
Lady beetle, meet spider. Boca Raton, FL. May 8, 2015.

Lady beetle, meet spider. Boca Raton, FL. May 8, 2015.

And then the strangest thing happened: the spider just remained motionless while the beetle climbed on the spider's back, tumbled off onto the disk portion of the flower, and then scurried away out of sight!
Let's make a closer acquaintance.

Let's make a closer acquaintance.

So long, and thanks for stopping by. (The beetle is visible to the lower left of the spider.)

So long, and thanks for stopping by. (The beetle is visible to the lower left of the spider.)

I wasn't able to snap a picture of the scene as the beetle left, but I was certainly surprised to see what I assumed would be a typical predation scenario turn into nothing at all. In case you're curious, the lady beetle looks very much like the "metallic blue" lady beetle, Curinus coeruleus, although it's by far the smallest one of them I've ever seen. References Marshall, S., & G.B. Edwards. 2008. Florida’s Fabulous Spiders, 4th ed. Hawaiian Gardens, CA: World Publications. Ubick, D., P. Paquin, P. E. Cushing, & V. Roth (eds.). 2005. Spiders of North America: An Identification Manual. Keene, NH: American Arachnological Society.