Depth of field redux

A couple of years ago as I was just starting out in macro photography I experimented a little bit with depth of field using a beautiful male Citrine Forktail damselfly. Since then I've switched to a new macro lens and taken a lot more photos, but not much has changed. I still love how depth of field can be used to capture different elements of a scene; how it can make for a tack-sharp picture where everything's in focus or highlight just the item of interest and leave the rest blurry (know-it-alls call this this bokeh). Me, I'd like a little less bokeh in my pictures, since I'm usually shooting macro. I dream of a macro lens that might have more than a few millimeters of depth of field. Nonetheless, playing around with it is fun. One weekend morning I was able to sneak up on a couple of different butterflies nectaring on different flowers of the same small plant, Spanish Needles (Bidens alba or B. pilosa depending on which botanist you subscribe to, although the latest edition of Wunderlin and Hansen specify that B. alba is our common weed and B. pilosa is rare). Those of you who aren't on a mobile device should be able to hover your cursor over the image to watch how the narrow depth of field makes the effect of focal point very clear: these two butterflies are only a few inches apart, but they might as well be miles:
Mallow Scub-Hairstreak (Strymon istapa) nectaring on Spanish Needles. Boca Raton, FL, May 10, 2015

Mallow Scub-Hairstreak (Strymon istapa) nectaring on Spanish Needles. Boca Raton, FL, May 10, 2015. Put your cursor over the image (or click here) to change the focus to the foreground butterfly, Dainty Sulphur (Nathalis iole).

Those of you who can't hover your cursor will have to click the link in the caption to see the second image, which has the advantage of bringing it up at a larger size, as well. To prove that no butterflies were harmed in the making of this photo experiment, here's a shot of the sulphur departing the scene afterward:
Dainty Sulphur (Nathalis iole) doing a backflip. Boca Raton, FL, May 10, 2015.

Dainty Sulphur (Nathalis iole) doing a backflip. Boca Raton, FL, May 10, 2015.

If I'd had a wider depth of field, perhaps the darn thing would even have been in focus! And, just for fun, here's the butterfly staring me down with righteous indignation for this gross violation of his privacy:
Dainty Sulphur (Nathalis iole). Boca Raton, FL, May 10, 2015.

Dainty Sulphur (Nathalis iole). Boca Raton, FL, May 10, 2015.

Mallow, scrub, and hairstreaks

More and more butterflies are appearing in front of my lens; I doubt that's because there are in fact more butterflies in my yard. It's much more likely that this phenomenon is the result of my camera lens being pointed outdoors more and more frequently as the north wind continues to keep the weather nice and my lunch breaks take advantage of it. (I am d-r-e-a-d-i-n-g the onset of the southerly breezes and their summer heat 'n humidity, which can't be far off, now.) Today's lunchtime views come to us courtesy of a couple of weedy species: the common weed Bidens alba, aka Spanish Needles, and the common butterfly, Strymon istapa, aka Mallow Scrub-Hairstreak. (To be fair, I should add a third weed species, Common Fanpetals, Sida acuta, which is the larval food for the butterfly.) The first weed, which I try to pull up whenever I notice it on account of its wickedly clingy seeds (see below), nevertheless has a pretty flower with a yellow corolla and white petals. It provides much-needed pollen for many insects when there's nothing else abundant and in flower. And if there's one thing this flower can be said to specialize in, it's abundance, on account of those aforementioned (and below-pictured) seeds. They are about 0.25–0.5 in (0.6–1.3 cm) long, ribbed, and individual seeds look somewhat like needles; they have from 2 to 6 barbed hooks at each end (most commonly two, bi-dens). The seeds are borne in loose round clusters that somewhat resemble the traditional "peony" firework display:
Bidens alba seedhead. Note the twin teeth on each little spikelet. Very effective at hitching a ride.

Bidens alba seedhead. Note the twin teeth on each little spikelet. Very effective at hitching a ride.

Here's a close-up of those teeth:
Bidens alba seedhead (detail).

Bidens alba seedhead (detail).

As I found out from the Floridata page about this species, a single plant is capable of producing 3,000–6,000 seeds, which maintain viability for at least 3-5 years and germinate readily. If left unweeded, this little flower will soon carpet your property, causing untold annoyance when your toddler tramps through the weeds. Launderers and laundresses, beware the bidens! (I also found out that the "correct" common name of this plant is "shepherd's needles," but no one here in South Florida uses that name.) As I mentioned, though, this little weed is very attractive to the local pollination crew; bees, butterflies, and even beetles, can't seem to get enough of it. Floridata has a partial list of lepidopteran visitors to the blossoms:
[They] are a favored nectar source for many species including the great purple hairstreak (Atlides halesus), the dogface (Zerene cesonia) the red-banded hairstreak (Calycopis cecrops), the lantana scrub hairstreak (Strymon bazochii), and the gray hairstreak (Strymon melinus), and many others.
Our local scrub-hairstreak, the Mallow (Strymon istapa), is no stranger to this little flower, as you can see. Here it is, proboscis coiled as it anticipates how best to attack this scrumptious snack:
Strymon istapa (Mallow Scrub-Hairstreak), Boca Raton, FL, March 28, 2013.

Strymon istapa (Mallow Scrub-Hairstreak), Boca Raton, FL, March 28, 2013.

And here it is, proboscis uncoiled, rooting away among the multiple carpels (the "yellow stuff" that you see "inside" the flower):
Strymon_istapa_unfurled_20130328

Strymon istapa (Mallow Scrub-Hairstreak), proboscis extended. Boca Raton, FL, March 28. 2013.

I've written this species up before on this site, but since it was a short article and I didn't have such a wonderful macro lens as I have now, I figured I'd give it a "relook" as they say on the subcontinent. Cech and Tudor highlight the characteristic that makes this butterfly so much fun for the photographer: "imperturbable." As I said when I wrote it up last time, it stays put ("If only all butterflies—and any bird—were this easy to photograph!") As its name implies, its larval host plants are in the family Malvaceae; after puzzling over the identity of one of the many weeds in my yard, research conducted for this blog post clinched the ID for me: Sida acuta, aka common wireweed, aka common fanpetals, is the larval hostplant for this butterfly. Here's a picture from the interblogs; I'm happy to report that, thanks to a recent bout of weeding, I don't have any specimens worthy of photographing, although I do have several little ones that I need to get out of the ground:

Sida acuta, from the website of Belgium's Royal Museum for Central Africa.

If you want to know more about this plant, check out Stephanie Sanchez's page over at heuristron.net; she's always got something interesting to say! This is one of the reasons I write this blog: I've been pulling this weed for over two years, never realizing that it's the larval plant for one of my favorite little butterflies! From now on, when I weed this plant, I'll be sure to leave a few behind (heh heh—as if it'll be by choice!) in hopes of one day seeing the Mallow Scrub-Hairstreak caterpillar. References Cech, R. and G. Tudor. (2005). Butterflies of the East Coast: An Observer's Guide. Princeton UP. Minno, M. F., J. F. Butler, and D. W. Hall. (2005.) Florida's Butterfly Caterpillars and Their Host Plants. Gainesville: UP of Florida.