You know it’s May at my house when the Fragile Forktails start flying

Exactly five years to the day after I found my first Fragile Forktail damselfy (Ischnura posita) in the back yard, this morning I found another one:

Fragile Forktail (Ischnura posita). Boca Raton, FL, May 10, 2017.

After looking through the archives of this site, it certainly seems that May is the month for these little guys. Nearly every year it seems I'm posting a mention or a photo of them in this month, and very rarely in any other. Now if only I could regain my steady hands from a couple of years ago; most of my recent photos are much blurrier than they should be. Sigh...

Dragonflies and damselflies returning to the yard

After a dry beginning to March (and no rain since then, but at least the heat's moderated a bit for the past few days), the odonates have started returning to the yard, just in time for the equinox! One or two of them run into mishaps:
Watch where you fly! Halloween Pennant (Celithemis eponina) served up for breakfast to a spiny-backed orb weaver (Gasteracantha cancriformis). Boca Raton, FL, March 18, 2015.

Watch where you fly! Halloween Pennant (Celithemis eponina) served up for breakfast to a spiny-backed orb weaver (Gasteracantha cancriformis). Boca Raton, FL, March 18, 2015.

but by and large they are still the most formidable airborne insect predators out there. Most of them sprint to safety as I approach, although the Blue Dasher is often more docile,
Blue Dasher (Pachydiplax longipennis). Boca Raton, FL, March 19, 2015.

Blue Dasher (Pachydiplax longipennis). Boca Raton, FL, March 19, 2015.

as is a chilly Eastern Pondhawk in the early morning:
Eastern Pondhawk (Erythemis simplicicollis). Boca Raton, FL, March 20, 2015.

Eastern Pondhawk (Erythemis simplicicollis). Boca Raton, FL, March 20, 2015.

The smaller and daintier damselflies are generally more approachable with a camera even after the sun has warmed them up a little; after the "chill" of the morning burns off, most of my dragonflies sprint away as I approach. Damselflies, on the other hand, sit still so you can sneak up on them. And, if you look at the bottom of the photo below, other creatures have little difficulty approaching as well.
Rambur's Forktail (Ischnura ramburii). Boca Raton, FL, March 20, 2015.

Rambur's Forktail (Ischnura ramburii). Boca Raton, FL, March 20, 2015.

Since I didn't notice the spider until after I'd come inside to view the photos on the screen, I have no idea what kind it is. Presumably a flower spider of some sort; it's quite small, given that the damselfly is no colossus itself. Happy first day of spring!

Odonates returning

As the calendar turns from January to February, damselflies and dragonflies are returning to the yard. Today three lovely male Citrine Forktails (Ischnura hastata) were in the back yard while I was baby sitting for three-year-old Daniel, home with a respiratory infection. (Yay, work from home.) While he was helpfully turning the back yard into mud, I was able to corral one of the damselflies near a lovely blue Salvia flower on the side of the house (it's not Tropical Sage, Salvia coccinea, but a new variety I picked up recently—long enough ago, though, that I forget which species it is):
Citrine Forktail (Ischnura hastata). Boca Raton, FL, February 3, 2015.

Citrine Forktail (Ischnura hastata). Boca Raton, FL, February 3, 2015.

Pretty as a picture. I just love these little guys. I saw one or two of them in the yard in January, but I'm pretty sure this is the first time this year we've had three at once.

Citrine forktail

Last week I started to notice the persistent presence in these here parts of those ephemeral and infernally hard to see odonates, the damselflies. Two forktail species, Rambur's and Citrine, (Ischnura ramburii and I. hastata, for those of you keeping score at home) are the only ones present so far, but I'm sure that soon I'll see the bluets again. I'm generally only able to go out on photo safari during the lunch hour (I do have a day job, after all), and I've found that the local damselflies are pretty wary in the middle of the day. But the other afternoon I was able to sneak up on one bright yellow male Ischnura hastata (Citrine Forktail); it was quiescent enough to allow me to discover the effects of depth of field on odonate photography. These animals are small, but in macro photography, small distances matter. As Sid Dunkle, coauthor of the recent monographic  guide to the damselflies points out, depth of field is critical to successful odonate photography.  In the photographic Supplement to Damselflies of North America, the standard treatment of the zygoptera, Dunkle writes that
I have had the near eye and the tip of the abdomen of a damselfly in focus, but the near surface of the thorax was out of focus! ... The film plane [or in my case, the CMOS chip] must be aligned exactly with the longitudinal axis of the body to get both head and tip of abdomen in focus. A lot of patience is needed!
In my case, patience was needed simply to approach these maddeningly elusive little beasts. I say maddening because one would expect that a relatively large and slow-flying animal like this would be pretty easy to keep track of once spotted. But nothing could be further from the truth. It might just be my aging eyes, but I found it quite difficult to keep my eye on these little buggers as they flew from brightly lit areas to shade, and from grass stem to grass stem. At times I found it easier to track them by their shadows than by their actual bodies! But once you get a damselfly quiet, it is indeed possible to approach them closely enough to capture some successful photographs, as the gallery below indicates. It's also possible to discover just how critical focusing is in macro photography. I took many more than seven photos, of course; these are just the ones that are anywhere close to being keepers, or that can serve as instructional reminders for myself.  

Spread your wings at Pondhawk

The Monday after Thanksgiving is a great time to get out to a nearby natural area. While most folks are back at work after a four-day weekend, those of us who have the foresight to request this day off get to experience something fairly rare around this time of year: solitude! The prospect of some alone time, combined with the knowledge that two of Palm Beach County's best birders had reported a juvenile Red-headed Woodpecker at a location near me decided my destination on this fifth day of a four-day weekend: Pondhawk Natural Area, which, as loyal readers of this blog know, was formally opened just a couple of months ago. And on this day, as expected, I had the place all to myself! I started out on the concrete walking trail, chasing warblers and other birds as the fancy struck me, and I wound up assembling a fairly respectable list without even trying very hard—28 species, including House Wren, American Kestrel, Osprey, Red-shouldered Hawk, and the target bird: Red-headed Woodpecker. But that wasn't the only, or even the primary, goal of the excursion. I just needed to get back out into one of the prettiest natural areas in Boca Raton. It's a very pretty park, with 5 different ecological communities (you can't really call these tiny snippets of area "ecosystems")—scrub, scrubby flatwoods, mesic flatwoods, hydric hammock, and sawgrass slough. I spent most of my time on that concrete trail, which winds through the mesic and scubby flatwoods (yellow and green areas in the map below) that surround the pond (the orange hydric hammock in the map), but I also took an excursion onto the sandy trail that leads through the southwestern portion of the site (also mesic and scrubby flatwoods). I never did get onto the trail through the scrub proper. Both scrubby flatwoods and "true" scrub are dominated by shrubby, scrubby plants that don't need a whole lot of water: sand live oak, saw palmetto, prickly pear cactus, etc. Where there are "woods" around (hence scrubby flatwoods), they are usually sand pine or, in slightly wetter scrubs (mesic, halfway between dry [xeric] and wet [hydric] sites), slash pine. The flatwoods areas at Pondhawk have numerous snags (dead trees left standing in the wake of a wildfire on this part of the site back in 2010) and living slash pine trees, providing excellent foraging and even nesting habitat for woodpeckers like the red-bellied (common in Palm Beach County) and red-headed (much rarer in Palm Beach County): Another characteristic plant of scrub or scrubby flatwoods is Feay's Palafox, with its interesting tubular flowers arranged into a very pretty cluster (called an inflorescence): You should always look closely at flowers; then, when you think you've seen everything, take a picture. I knew there was an ant hitchhiker on this flower, but I didn't notice the pale creature on the second "tube" from right until I got the image onto the computer. I have no idea what the pale creature is; I was assuming jumping spider at first, but it's not in focus and no matter how hard I squint, I can only make out 4 or 5, not 8, legs. And the body is rather elongate for a spider, although some of those tiny jumping spiders can be fairly "tubular." Heck, it might not even be an animal! When I arrived at Pondhawk, I was just hoping to see some pretty scenery like that flower; I had little to no expectation of actually encountering the "object" of my visit (the aforementioned Red-headed Woodpecker). I don't chase birds, and I don't really even go out of my way for them; I just like to get out into nature and, while I'm there, they're one of the more interesting things to look at—when I can tear myself away from the plants and the insects, that is. And when I do set out with a specific bird in mind, more often than not I miss it, anyway, so perhaps I'm only making a virtue out of necessity by deciding to focus on the whole experience, rather than the "goal." This time, though, I got a bit lucky: I actually did "get" the bird. I can't say, though, that I got a satisfying picture of it; it was always just too far away, or just on the wrong side of the sun, or the sun was behind a cloud, or it flew right over my head and I couldn't focus fast enough. Still, I managed to document the bird, which was nice: Everyone's still a bit confused about what this bird is doing here, so far south of its known nesting sites in the county. Red-headeds are slightly migratory, in that they move locally in winter to exploit better resources than they can find near their nesting sites, but only if their nesting sites are deficient in some food resource. Up north, a poor mast crop (acorns) is what triggers this migratory response; down here, with seemingly abundant year-round resources, it's a bit of a mystery why this juvenile bird would wander like this. Eventually the woodpecker got tired of me chasing it from snag to snag, and decided to fly right over my head (too quickly for me to get a picture, drat it) and back up to a site far enough away that it wasn't worth hiking over to, so I continued on my way and left him (or her) in peace. On the way out I got a couple of other decent shots, like this Red-shouldered Hawk perched on a tree overlooking the pond, thus doing its best to look like the avian version of the "pondhawk" for which the site is named: What really got me excited, though, was my first-ever sighting (well, documented with a photo anyway) of one of the spreadwing damselflies, Carolina Spreadwing (Lestes vidua): Carolina Spreadwing is the only spreadwing we're likely to see this far south in Florida; the only other species that occur in our area are either blue or green, not mostly brown. Very little appears to be written about this species, so I can't tell you much about it. The generic name, Lestes, means robber (some say predator) in Greek; vidua means widow in Latin. The official etymologists of North American odonates, Paulson and Dunkle, list this specific name as "widow; allusion unknown." And that's all I can tell you about it as well! This very young female (based on coloration) did her best to elude me, and she even exhibited some behavior that our great Florida odonatologist, Sid Dunkle, describes as follows:
Interestingly, they close their wings over their backs, and drop their bodies to parallel their perch, when a dragonfly flies near. Pairs in tandem do this also, but the approach of a human does not elicit this behavior.
Now, there were plenty of dragonflies flitting about, so I can't exclude the possibility of this damselfly doing this in response to them rather than to me, but on both perches that I chased this little lady to, she closed her wings over her back in what I thought was a response to my approach: This behavior confused me so much that I couldn't be positive this wasn't a "normal" damselfly that was exhibiting spread-wing behavior, rather than a spreadwing exhibiting "normal" behavior. When I got home and read Dunkle's description, I felt a little better about my ID on the bug. It still hasn't been confirmed by either bugguide or Odonata Central, but I'm fairly confident she is who I say she is. Hope to see you out and about next time!

New Backyard Bug: Nehalennia pallidula


Damselfly behavior notes: Everglades Sprites in tandem

Part of the fun of documenting the presence and behavior of the animal and plant species in your back yard is the opportunity to contribute, in however slight a way, to an improved understanding of our world. My "study site," which is my 1/4-acre property in downtown (but basically suburban) Boca Raton, is small enough that most of the animals come and go, and while I welcome those that come, I can't follow them when they go. That means that for most of the organisms I write about on this blog, I take a few snapshots, do a little book research (often in 18th- and 19th-century taxonomic catalogues that are now available online thanks to Google Books), and that's about it. I wave goodbye to the species and hope to encounter it again someday. But I've always wanted a richer, deeper encounter, one where I can see how this animal actually behaves. A couple of weeks ago, I got a taste of this kind of observation, when I was lucky enough to observe a pair of Rambur's Forktail damselflies (Ischnura ramburii) copulating on one of my young Bitterbush plants. This week I got another, more prolonged encounter with another species, Nehalennia pallidula, aka the Everglades Sprite. I happened to observe a pair in tandem as I was doing my daily perimeter patrol with camera. This is a species for which as recently as 1990 the mating behavior was completely unknown (Dunkle 1990). Since that time, more has been discovered, enough so that Paulson (2011) is able to write about the timing of sightings of mating pairs, but it's still kind of fun to be able to add to the behavior accounts of a little-known animal. It's been decades since I wrote a biology report, but I was inspired by this event to try my hand at it; I apologize for the rather dry nature of the rest of this post, but it was a lot of fun for me to write. And I stuck in a lot of pictures, so I hope that'll make it interesting enough for y'all! Date: Tuesday, May 15, 2012. Time: 9:45–11:05 a.m. EDT. Weather: Partly cloudy, intermittent light rain in area. 81°F, 30.02 mm Hg at start, 83°F, 30.03 mm Hg at finish. Site information: Small suburban backyard in Boca Raton, FL (26.35691°, -80.09095°) with water present (not a viable oviposition site, as it is a well-maintained swimming pool, although there may be standing pools of water in neighboring properties). Vegetation includes numerous herbaceous forbs, grasses, vines, and woody plants approximately 1.5 m south of a wooden 1.6-m tall privacy fence, and 2 m north of a 1.25-m tall mesh pool safety fence. The ground slopes down approximately .75 m between the two fences, which are separated by about 3.5 m. Five zygopteran species have been recorded on the site: three forktails (Ischnura ramburii, I. hastata, and I. posita), a bluet (Enallagma sp., likely doubledayi), and a sprite (Nehalennia pallidula). Observations During the past two weeks the site has been visited by several zygopteran species, including at least 4 individuals of Nehalennia pallidula. Rain has become more frequent and intense in the past four days, and today, during my daily inspection of the property, at 9:45 a.m. EDT I observed a pair of Nehalennia pallidula (Calvert, 1913) perched in tandem on the inflorescence of a 1 m2 Heliotropium angiospermum; small runners of the vine Passiflora incarnata were growing intertwined with the plant as well. The damselfly pair was motionless for some time, but took flight as I approached closer (approx. 0.5 m). The pair flew to a different perch nearby, this time on a nearly vertical, and fairly slender, stem of P. incarnata. They remained there for some time (I estimate >10 min, but I did not have a watch with me, so was relying on the time stamp of my digital camera), during which time the male flexed the tip of his abdomen rhythmically about once every second, thereby swinging the female, presumably in an attempt to bring her into the copulatory position (Stage D of Corbet's diagram). In this image you can see that the male's tail tip is strongly flexed, and the female's tail tip is blurred by the motion, but her abdomen is straight: The swinging was relatively rhythmic, approximately once per second for approximately one minute, followed by a shorter (<30 seconds) rest period, after which the male resumed flexing the abdomen. This flex–rest cycle happened five times, throughout which (and indeed throughout the encounter) the female remained with abdomen rigid and legs tucked under the thorax. At one point the female fluttered her wings, but the male was not induced either to release her or to move to a new perch. The male's wings were observed to be held slightly spread, rather than folded together over the back as in the normal (horizontal) perching position. Presumably this allows greater stability to support the weight of the female while perched in tandem. The female's legs are folded up tight to the thorax, presumably to minimize drag in case the male needs to move the perch. After about 10–15 min, a lizard moved close to the pair, after which the pair changed perches 3 to 4 times in less than a minute before settling back on another stem of Passiflora incarnata; this one quite a bit thicker than the first: They remained on this perch for some 3 minutes (until 10:02), after which I lost track of the pair and assumed they had left the area. I later (10:10) discovered that a single male Ischnura posita had come to occupy the part of the plant that the pair had briefly visited before disappearing: I assumed that the arrival of this individual had prompted the departure and perhaps even separation of the N. pallidula pair, as I later (10:36) noticed a lone female N. pallidula near the original site of contact. This female, however, seems to have been a different individual—the amount of black on abdominal segments 9 and 10 appears greater, and I am fairly sure that the female in the tandem pair did not have a mite on her thorax, while this lone one did (although the legs of the female in tandem were folded under the thorax, which prevented me from observing the presence or absence of mites): At 10:38 I found the tandem pair again and was able to observe them for another few minutes before I lost track of them again (at 10:42). I assume that they separated afterwards, because at 11:04 a.m., I observed a lone N. pallidula who closely resembled the female of the pair (at least, this individual's tail markings were very similar, and she did not have a mite on her thorax). Discussion In 1990, Dunkle wrote that the biology of this species was unknown; Paulson, writing in 2011, was able to give some details about when mating pairs are seen (only after the rainy season has begun). While it's not clear that this pair did mate, it is evident, based on these observations, that tandem flight in N. pallidula lasts at least one hour, probably more. I did not observe copulation, although I was unable to determine whether it was because the female was immature or unwilling, or whether it did occur but during the time I was unable to observe the pair. Etymology As usual, I like to provide the etymology whenever I can. Nehalennia is a river goddess depicted on numerous votive altars from the area where the Rhine river flows into the North Sea. The English name for the genus is Sprites; according to Paulson and Dunkle's checklist, this name comes from the fact that "species are tiny and difficult to detect." The scientific name, pallidula, means "little pale," which, again according to Dunkle, refers to the "greater extent of pale color on sides of thorax than other Nehalennia." References Dunkle, S.W.  (1990). Damselflies of Florida, Bermuda, and the Bahamas. Gainesville, FL: Scientific Publishers. Paulson, D.R.  (2011). Dragonflies and Damselflies of the East. Princeton, NJ: Princeton UP. Paulson, D.R.  and Dunkle, S.W. (2012).  A Checklist of North American Odonata. including English Name, Etymology, Type Locality, and Distribution. Available online.

New backyard bug: Ischnura posita

One thing that I'm really enjoying about the new place is that I've seen several species of damselfly in the backyard in the little more than a year that we've been here. The old place had lots of dragon- and butterflies but, perhaps because there was no backyard pool, there were no damselflies, at least that I recall. So far I've seen a couple of species of Forktail (Ischnura ramburii and I. hastata), a sprite or two (Nehalennia pallidula),  a bluet (Enallagma sp., probably doubledayi) and an unidentified spreadwing species ("documented" by perhaps the worst photo I've ever taken). Today I saw a third forktail species, Ischnura posita, the Fragile Forktail. The male is a very handsome fellow, with stunning green eyes (black on top), a black thorax marked by two interrupted stripes (Dunkle characterizes them as "a a pair of upside-down exclamation marks"), and a long, mostly black abdomen with most segments marked by green rings right where it meets its neighbor: I've been hoping to catch a glimpse of this fellow for quite some time; ever since I got my two damselfly guides this year (the 2011 Paulson guide to Eastern dragon- and damselflies, and the 1990 Dunkle guide to Florida damselflies). It's just a very good-looking bug! Here's another angle for those of you who can't quite get enough of him: Look around your yard; see what you find!

New backyard bug: Ischnura hastata (Say)

Some insects look so delicate and fragile that it's hard to remember that they can be among the most ferocious predators, at least for their size, on the planet. Case in point: the tiny little yellow damselfly Ischnura hastata, commonly known as the Citrine Forktail. It's only about an inch long and its wings look so delicate and flimsy it's a wonder that it can fly at all: But the damselfly, like its larger cousin the dragonfly, is a voracious predator both as larva and imago (adult). According to the most recent (and best) field guide published on odonates of the eastern United States,
Odonates are all predators, in both adult and larval stages... Most dragonflies take small prey, much smaller than themselves. Tiny flies, leafhoppers, and beetles are common prey. Some species vary these with larger prey, for example other dragonflies and butterflies, and others seem to be specialists on large prey... [S]ome pond damsels will take another damselfly of the same size, especially when the latter has just emerged and is quite vulnerable. Note that dragonflies that routinely take large prey are among the most effective biters when captured!

[Paulson 2011]

I've never been bothered by biting dragonflies or damselflies, but then, I've not yet invested in an insect net to capture any, either, so perhaps I should just leave that alone. My preferred mode of capturing insects is via my camera's imaging chip.

There have been relative hordes of damsels in the front and back yards lately; I suppose that means spring has sprung. Cheers!

Oops! Almost forgot the etymology.

It took some searching, but this Italian paper finally gave me the origin of the genus name Ischnura:

Ischnura - ισχηοσ = gracile + ουρα, ασ = coda; dalla coda gracile. Per la forma esile dell’addome.
My Italian is a mite rusty, but it looks like it means "from the gracile [a hifalutin English word meaning slender] tail. For the slender form of the abdomen." As for the species name hastata, that presumably comes from the Latin hasta, "spear." So this tiny little damselfly's taxonomic name basically translates to "slender spear." Say's original genus name for this species was Agrion, which presumably came from Greek agrios, wild. So "wild spear" was what he had in mind when naming this species, which later came under the older genus name, Ischnura.