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.
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:
Damselfly behavior notes: Everglades Sprites in tandemPart 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. 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: Ischnura posita had come to occupy the part of the plant that the pair had briefly visited before disappearing: 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.
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!
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.