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.
Some insects feed on rosebuds, And others feed on carrion. Between them they devour the earth. Bugs are totalitarian.
—Ogden Nashmy yard has been veritably plagued by them for weeks now (if you can call the presence of beautiful little insectivorous fliers a plague). Just to show how many there were, here are a male and immature female jockeying for space on the same wildflower/weed in my front yard: One study of just one type of parasite (gregarines, one-celled protozoans) demonstrated that these organisms tend to be host-specific as well, so when you add up the number of kinds of parasites, then multiply by the number of known species of hosts, you're dealing with astronomical quantities.) The female of Rambur's Forktail is polymorphic, which means that she comes in more than one color form (but only one per customer, please). The individual pictured has what is known as andromorph coloration (from Greek andro-, "male"); that is, her color is almost exactly like that of the male. Her thorax, though, unlike the green thorax of the male, is blue. This color difference means that she is technically immature; if she were older, it would be green just like the male's. How can I prove that she's female? Well, today it was pretty easy: she's the one on the bottom in the wheel, or heart, position:
Male Odonata are unique among exopterygote insects [ie, those that undergo incomplete metamorphosis, with only egg-larva-adult stages of life, rather than complete metamorphosis, egg-larva-pupa-adult] in having the primary genital orifice and the intromittent organ located at opposite ends of the abdomen. (Corbet 1999)During copulation, the female's tail tip is pressed up against a secondary genital structure located between the male's second and third abdominal segments. That structure, called the seminal vesicle, has been packed with sperm from abdominal segment 9, right near his own tail tip—how he manages to first clasp the female and then transfer the sperm would be a complete mystery to me were it not for the helpful illustration from Corbet that I reproduce below—and is being pressed up against the female's tail tip so the sperm can be transferred from said vesicle to her spermatheca; any eggs that pass through that spermatheca then become fertilized. Here is a graphic representation of the process from the dean of odonate studies, Philip Corbet (you have to click the image to see all 8 stages; the thumbnail cuts the picture off mercilessly):
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.