I have a special request for reporting on any rain we get during the upcoming week, so here it is: finally we got rain last night. It fell in three waves, with moderate lightning and thunder and amounted to 0.56 inches here in Wolfskin (1.31 inches in June), 0.76 inches fell in Athens (of June’s 1.22 inches), and the average June would give us 4.0 inches.

Here are some of the CoCoRaHS stations reporting yesterday by 9AM EDT. The 0.56 in southwestern Oglethorpe is me.


June 2008 was the third driest June since 1920, with 1.22 inches. June of 1988 gave 0.91 inches, and June of 1958 gave 0.87 inches.

Since it’s the last day of June, and half the year has now gone by, it seems appropriate to take a look at the extent of rainfall.

We’ve seen this before, and I’ve updated it now. The red line shows the average accumulation of rain during the course of an average year. The green line shows 2008 so far, set among rainfall accumulations for 2005-2007. We are now, in 2008, just about to drop below the rainfall accumulation for 2007, and have already done so for 2006.



The above plot is a bit misleading, since it ignores surpluses and deficits in previous years. We can take care of that with this plot of total accumulation since January 2005.

The left axis shows accumulation in inches, with the red line again indicating the average expected, and the green line showing actual.

The right axis, and its blue line, offers an evaluation of the difference between the average and actual and with the addition of June shows a continued deficit.

Both sets of interpretations shows that it would take us two feet of additional rain to be back to normal levels expected since January of 2007. (Of course we don’t want that two feet all at once, not even six consecutive months of double the rainfall that it would take.)



The crossover of the red and green lines shows the beginning of the drought as determined by deficit. It’s somewhere around January of 2007 that we began to fall behind. But the blue line tells us that it’s really January of 2006 that the decline in monthly rainfall began, with a few months of normal activity in late 2006.

Here’s the perspective over the annual rainfall expected during the first half of the year, since 1920. Average expected rainfall over Jan-Jun is 26.10 inches. We have received the eighth lowest amount of rainfall during the first half of the year, 16.19 inches, since 1920. This is only the tip of the problem, since 2000 (#7 at 15.72 inches), 2004 (#2 at 13.72 inches), and 2007 (#6 at 15.66 inches) also fall in the group of eight.

And so half of the eight driest first half-year rains in the last 89 years have occurred in the last nine years.

Sometimes you run across a fly that is just charming. I’m hoping someday to encounter stalkeyed flies but in the meantime this will have to do, piggybacking from the bottlebrush buckeyes of yesterday.

The little wasp mimic flies I mentioned yesterday have proven to be the most difficult subjects to photograph. They are tiny, less than a centimeter, in near-constant motion, alighting for no more than a second or two. Out of sixty photo attempts only three proved marginally adequate. I’m pretty sure now that they are Ocyptamus. The leading wing pigmentation and abdominal markings most resemble Bugguide’s O. costatus. This fly is therefore one of the many syrphids.

Strictly interested in the pollen. No nectar here!


Admittedly I did take all these under conditions that usually result in good photographs for rapidly moving subjects - 1/200 second and everything else adjusts automatically. I only do that in bright light, which this was. Maybe I should try setting the aperture, or even going to manual and setting both!


It was certainly adequate for capturing the image of this tiny presumptive tachinid fly.

The bottlebrush buckeyes ( Aesculus parviflora ) are in flower right now, months after their red and painted relatives, and the insects are going crazy. The only one I have a reasonably clear id for is this presumptive Epargyreus clarus, silver-spotted skipper.

Some of the insects are actively engaged in the flowers (the bumblebees and tiny bees especially), and others are using the shrub with its thick dressing of leaves as a landing platform. These two probably have different priorities but I like the juxtaposition.



The bug on the left almost surely has to be a white-margined burrow bug, Sehirus cinctus seen last, in early May, but none of the bugguide images of this species shows yellow legs and antennae. The fly? I’m guessing a sarcophagid, but at the moment I won’t go further than that.

This fly was also lying in wait on a leaf and was elusive. I don’t know that I’m going to encounter it again but it puzzles me. The patterning reminds me of a syrphid, but look at all that fur! The syrphids look to be uniformly hairless, with their gaudy coloration a function of the exoskeleton, not the hairs.

The stance and behavior reminded me of robber flies, but I’m not seeing anything that hits.



This fly was clearly drawn to the anthers, a pollen guzzler. I don’t think it was interested in nectar. But it was also elusive and picky, hovering like the wasp it resembles and repeatedly declining to come to rest.



There are all sorts of possibilities here. It could also be a syrphid, maybe of the Syrphini, Ocyptamus, perhaps O. fascipennis, but the wing coloration isn’t right.

I’ve been fooled before, characteristically wisened up by Bev who gave me my first introduction to Conopidae, Thick-headed Flies and wasp mimics. This is probably not Stylogaster, but that discovery is worth a revisit from last August. I’m particularly proud of those photographs.

I could also be one of the Conopinae, such as Physoconops or Physocephala, but though the wings are roughly right, the abdomens are not. Surely the big red eyes and knobby antennae are informative, but not so far for me.

I’ll try to do some more photography today, hopefully clarify these images, and continue a multi-part story.

There’s nothing quite so photogenic as a praying mantis. They’re just not like other insects, beebopping along doing their own thing and not seeing you.



“Yeah, sure, the guy with the camera is big, but I can take him on.”

Yesterday was notable, not for the 0.01 inches of rain that fell in the early afternoon (although we are certainly grateful), but for the extremely close lightning strike. I was sitting out on the front deck just before going to work when out of the corner of my eye caught the bolt apparently driving through the nearest trees and terminating somewhere up the driveway to the east. The thunderclap was enormous, and simultaneous with the bolt. The cats scattered just a bit faster than I decided to go indoors.

A bit earlier I encountered on the milkweeds this little flower crab spider. The leaf had been folded over, and it must have been with great difficulty for these leaves are very thick, and I peeled it back, disturbing her from lunch.



There are three look-alike genera of these sorts of crab spiders: Misumenoides, Whitebanded crab spider; Misumena, Goldenrod crab spider; and Misumenops, Flower spider. The species within each genus show quite a bit of color variation overlap, so that’s not the most useful field guide. What can be is the arrangement of the eyes and the presence or absence of a ridge across the face, as summarized on this bugguide comparison page.

This one has the ridge across the head, which seems to eliminate Misumena, which is also said to have all eight eyes visible when viewed from the front. Only six of the eyes are visible here, which would seem to target one of the other two genera. Now I have seen Misumenoides formosipes, on Sep 20 2007, but that was a wildly different color variation, and there don’t seem to be too many examples of photographs of largely white Misumenoides. So I think I’d go with Misumenops. Fortunately we have our flower crab experts who are much better at this than I am!

Oh - and I don’t know what the unfortunate dinner is. Not knowing how much it had been mangled I didn’t even try to id it.

In the end we got 0.30 inches of rain during the weekend in three events from Saturday morning through Sunday morning. That’s a total, so far, of 0.74 inches for May, with the forecast not very promising for the rest of the month. At this rate May will have less than 25% the amount of rain usually expected.

The temperatures have mellowed considerably over the last week, not rising much over 85, but that’s expected to end now, with highs in the mid 90s.

It might have been the weather, or maybe just coincidental, but spiderlings have been appearing synchronously in several locations on the large viburnum.


The mother is no longer present in any of these nests, so far as I can tell, so I can’t use her to id the babies. The spiders that have been seen the last month or so in these folded-over leaves have been the funnel web spiders, Agelenopsis; and running crab spiders, Philodromus.

The eye arrangments are fairly clear here. Don’t know how those persist as the babies grow, but these don’t seem to match the funnel web or running crab eye pattern page on Bugguide.

First up for your Sunday morning amusement, Oded enters a contest, with a little constructive criticism from Regan. OK, maybe more than a little:


I browsed through some of the folders of photos the last few weeks and found in 080606 a few photos that didn’t make it for various reasons.

It’s got to be an assassin bug, surely not a coreid. I’m guessing a young wheelbug, Arilus cristata, which we’ve seen before several times. The younguns don’t seem to have the wheel on the back, and there are plenty of photos at Bugguide of nymphs without wheels.



Nice to see the caterpillars of Battus philenor, Pipevine Swallowtail. I planted the Aristolochia macrophylla specifically for this reason. Last year the freeze came and all the leaves dropped off. It took at least a month for the plants to recover from that, so no larvae.



And finally a view of the maturing flower buds of Passiflora incarnata, Purple Passionflower, or Maypop if you prefer. The most mature is in the foreground, and the buds are earlier as you progress outward. The last couple of years have seen this particular plant chewed to bits by pearl crescent larvae (that’s ok though, that’s what they’re for). This year, for whatever reason, that hasn’t happened. I’m thinking great crested flycatcher, maybe.

I was startled to wake up to the sound of rain, early this morning, and it has continued gently and steadily since. Very welcome and it looks like it may persist.

Our NPR station has been simultaneously broadcasting three programs: mildly dippy light classical, It’s Only A Game, and the BBC. It’s fairly disconcerting.

Or it might be that I’m still in the Oded Gross mindset. I was listening to some of his music videos last night, and it may still be influencing my reactions. ( Just Found a Red Sock in the Laundry is pretty good and would make a pleasant and mildly uplifting Saturday interlude, if you care to listen.)

You’ve probably seen these amusing little jokes:



I filled my gas tank for the first time since May 6 (that’s how much I drive between semesters when I’m not going in for work) and was already prepared for $4.01.9 per gallon, which I imagine to be on the low end of what most are paying right now. There was, however, this notice now on all the pumps:



I don’t know whether the composition of gasoline that I’ve been using just changed or whether it’s been like that for some time and the notices just went up. At first blush this seems like a good thing - you might think that that’s cutting by 10% the amount of new CO₂ put into the atmosphere by driving. To a certain extent, that’s true, but as always, TANSTAAFL.

My chemistry background demands a closer look. The combustion of octane (the major component of gasoline) develops 4.1 times the energy of combustion of ethanol (and roughly, I’ll assume that drives the temperature and pressure per stroke). Burning octane produces 4.5 times the number of moles of gas (CO₂ and H₂O) as burning ethanol does. On a molar basis, the product (I’m assuming roughly that these two factors are multiplicative) of efficiency would be about 18:1 in favor of octane.

We don’t inject fuel into a piston on a molar basis though, it’s done (I guess) on a volume basis. There the higher density and lower molecular weight of ethanol works for us. On a volume basis the efficiency would seem to be about 1.8:1, in favor of octane. So ethanol would deliver about 55% the efficiency of gasoline, on a volume basis.

I figure that E10, gasoline spiked with ethanol to 10%, results in a reduction in mileage by 4.5%, i.e., if you’re used to 25 mpg, you’ll now get 23.9 mpg. Put another way, you’ll pay about $2.20 extra to fill your 12 gallon tank, since you’ll have to fill it more often.

As it turns out, I’m not too far off. The DOE site gives a figure of 3.3% reduction:

E10 (10 percent ethanol) has 3.3 percent less energy content per gallon than conventional gasoline. E85 (which currently averages 74 percent ethanol by volume) has 24.7 percent less energy per gallon than conventional gasoline. AEO2007 assumes that engine thermal efficiency remains the same whether the vehicle burns conventional gasoline, E10, or E85. This means that 1.03 gallons of E10 or 1.33 gallons of E85 are needed for a vehicle to cover the same distance that it would with a gallon of conventional gasoline. Although the difference is not expected to have a significant effect on purchases of E10, AEO2007 assumes that motorists whose vehicles are able to run on E85 or conventional gasoline will compare the two fuels on the basis of price per unit of energy.

It would be nice to think that only waste products were used in the manufacture of what would then be cellulosic ethanol. But as the DOE site also points out, the startup cost for a cellulosic ethanol plant that delivers 50 million gallons of ethanol a year is perhaps $375 million (2005 dollars), more than 5 times higher than one that uses actual food as a source for ethanol. Corn fruit and soybean or canola oil is simply much, much richer in terms of nutrient than cellulosic starting material. So that’s a major kink to be worked out (not to mention that 50 million gallons a year for one plant is barefly a drop in the bucket).

Another major kink is the energy cost of ethanol production, related to the above. The consensus right now seems to be that it costs more, in terms of energy, to produce ethanol than the ethanol delivers. That cost must include startup, transportation to and from, and all the chemistry involved in the conversion. It probably doesn’t include the third major kink:

I probably place more importance on the environmental costs than do others, but it seems to me that whether it’s corn, switchgrass, or other plant materials that provide the basis for ethanol production, all that has to be grown, and we don’t have a great track record for land use in agriculture. Monoculture and the use of inorganic fertilizers and pesticides, not to mention the extra conversion of wildland to farming, scares the crap out of me.

We really have to get this right, the first time, and we’ve wasted at least eight critical years and drained ourselves of enormous resource during the last six. It’s not just the immediate economy, it is that our civilization has gotten where it is by burning much of the easily obtained fossil fuels there exist. If we don’t get it right, there simply won’t be that source of concentrated, easily obtained energy for another try. The clock is ticking and it’s only going to get harder and harder.

(Oh dear, you have to dig a bit for it, since CNN doesn’t consider it to be major news, but the House just wrapped up a $165 billion dollar gift, lots of bows, no strings, for continued funding of the wars for the next few months. Those are resources, on top of the trillion or so dollars so far flushed down the toilet, that could have been spent on 440 new cellulosic ethanol plants, or any combination of a myriad of things that are becoming increasingly, desperately needed. Not good. I guess it’s 'cause the gays are getting married.)

Not very uplifting. Maybe I’ll go watch some more Ody.

Last night’s training session was quite good. Our newest member of the fire department showed up for the first time. With Brian gone to Oregon and the surrounding northwest states for wildland firefighting this summer, it augmented our training core group back up to the usual five or six. We’ve had a good bit of trouble with the Margaritaville in the last couple of months - battery discharge, mainly, so that it doesn’t start without charging. (This isn’t desirable in an emergency pumper!) We pretty much isolated the problem to the batteries themselves, there are four of wired together in parallel, and two are four years old. So hopefully the pumper makes a trip to have those checked out today, and then it should be in fine shape. If it’s a short somewhere in the truck that’s going to be much harder. The previous owners rolled her and there has been extensive rewiring since, so it will be a nightmare to try to figure that out.

Anyway, back home, Glenn noticed this structure hanging from the upper deck railing. It’s something you’d not usually see since it would be built either underground or in a long narrow cavity, out of sight. Clearly the builder wasn’t thinking right when she built it right in the open, with little in the way of attachment.



It’s probably the series of cells (the top cell fell out, upper left above photo) built by a leafcutting bee, Megachile spp. A Bugguide page matches it pretty well, including the sealed top of the cell.

The outer leaves are rolled and pasted somehow into a fragile surrounding wall but the cells themselves are much more sturdily cemented together, and I wasn’t able to open them without white fluid from the inside leaking out.



I’ve linked to this site before, and it has another matching nest photo.

Wow. It’s been practically frigid here the last couple of nights. Our low this morning was 54 degF, and that’s just verging on delirious. The days are getting up there, but only into the lower 90s. I have no problem with this.

So today, strictly for your entertainment, I’ll post some fluff, from Oded Gross, in a manner that I seldom do. I vetted it with my sister and with Glenn, and at least I agree (and that’s all that matters, for I am certainly not to blame) that it’s rather brilliant in furthering the case that gay marriage causes no end of problems, from the degradation of the sanctity of marriage, to meteor strikes. Enjoy.

A couple of dragonflies, both observed at the deck, have been clamoring for release for the last few days, and it’s been at least a few days since we’ve had a good dragonfly.

These represent the two great suborders of dragonflies: Zygoptera, the primitive damselflies; and Anisoptera, the true dragonflies.

This tiny damsel, barely a coupla centimeters long, was haunting the grasses in full sun, drifting here and there. I’m surprised I took note of it at all. Damsels are for the most part difficult but I’m guessing this to be a Citrine Forktail, Ischnura hastata, probably a male. There is a good bit of change in the coloration and patterning during the course of the lifespan of the adult, but that seems to be true for a lot of damsels.


What with the bewildering genera of dancers, bluets, sprites, and so forth in this family it could easily be something else, but it does have an entirely yellow tail and that’s supposed to be a red flag for the male of this species. If it were a female, I’d have been eternally confused, as you can tell from this profile page by Stephen Cresswell.

Now this one I’m fairly sure of: Widow Skimmer, Libellula luctuosa, and it’s probably a female (or a very young male - the males quickly become pruinose, or frosted white). Quite a number of these were hunting in precisely the same area on the deck as last Wednesday’s damsel above. There must have been a synchronous emergence since I had not spotted them until today.


Unlike most skimmers that I’ve encountered these are fairly weak fliers. They don’t skim, they practically flutter, something that caught my eye immediately. That was the first thing, along with the yellow striping, that made me reject the possibility of a whitetail (of which we have a huge number this year).


The dragonflies certainly have been abundant and diverse this year!

Doug confirmed in comments to yesterday’s skipper as Atrytone arogos, Arogos Skipper. A number of links, including this one, reflect Doug’s description as uncommon anywhere (the distribution map shows a concentration in the central US from mid-Texas northward) but overall the species is endangered and found only in isolated colonies, at least in Georgia. It’s been extirpated (wiped out) in several states including Illinois and is threatened throughout its range. So I’m certainly pleased to have found evidence of a colony in the Goulding Creek area.

I also thought it was pretty interesting, since management of wildland areas by fire has become quite the thing, to see this admonition (same link as above):

Management needs: Care should be taken not to extirpate populations through the use of fire as a management tool.

Of greater abundance (the image section at bugguide consists of at least a half-dozen pages of photos) is Common Buckeye, Junonia coenia. That may be so, that it’s common, but it’s the first I’ve seen in the immediate area. Don’t know that it’s a male but this is the behavior of one, sitting on low vegetation awaiting the arrival of a female. Apparently they also chase off other insects.



This fellow was expending energy at a prodigious rate, hovering at all times, punctuated by zooming off on occasion and then returning nearly precisely to its origin. Try as I might I could not get it to face me, but at least got two fairly decent subtly different shots.

The highlight was the broad gold band of the abdomen, as well as the helmeted eyes on the head that suggest a fly. I went unsuccessfuly through tons of bugguide photos of syrphids and robber flies, mainly on the basis of behavior, and then thought to put in the keyword “hovering”. Imbedded deep within the photos returned was the target: Hybomitra cincta.

This is a tabanid (Tabanidae), a species in the horse and deer fly family. The only common name I find is “horse fly”, but the common noxious critter we usually associate with horse flies is a different species (Tabanus spp). Whether this one is a biting one or not I don’t know, but it certainly wasn’t interested in me other than in keeping its distance. I would guess it’s a male and that its more interested in the possibility of females in the area.



Did I think it was a bee? Not for a moment, especially after the hint of the eyes from the back. And btw, the photos were taken at 1/200 second exposure, so even at that short time the wings are a blur.

Oglethorpe County seems to be maintaining its lead in the CoCoRaHS community with the addition of some new cool person yesterday or the day before. We’re now up to 13 stations reporting (I’m #12), and #13 is located strategically in the northeast part of the county, up around Vesta. It turns out our neighbor (#3) has moved either her station or residence to the Beaverdam area in the northwest part of the county. Now all we need is someone in the southeast Philomath area! (BTW, though our only traffic light in the county is in Crawford (#9), a few miles west from the county seat, Lexington (no traffic lights, #1 and #11)).



The thistles of yesterday were also attracting this skipper (June 11). I’ve looked through the skippers, especially the grass skippers, on bugguide, and as usual cannot find any species that satisfactorily duplicate this one.

The dorsal forewing pattern has this heart-shaped dark pattern and broad dark margins.



Doug has said that the ventral surfaces may tell more (and unfortunately, because they’re hidden, the forewings are the most informative). The hindwing ventral surfaces are pretty much without marking, but there does seem to be some spotting on the ventral forewing surface. The lack of spotting would seem to eliminate the hobomok or zabulon skippers, the grass skippers I seem to find most often.

That leaves two species, each in a different genus, as possibilities: Anatryone logan, Delaware Skipper; and Atrytone arogos, Arogos Skipper.

We may dislike thistles (USDA Plants declares ALL species to be noxious, whether or not alien), but they sure do put out the kind of flowers that insects like.

I thought this might be a flower scarab, and it is probably Trichiotinus lunulatus, Emerald Flower Scarab. It’s one of the Cetoniinae, the subfamily of scarabs that encompasses fruit and flower chafers.



This one is more of a southerner ( zipcodezoo distribution map ) but it does have a vaguely lookalike cousin species, T. bibens, that gets a bit further north.



This one was quite a large fellow, easily a coupla centimeters long, and was completely unselfconscious about diving deep into the thistle inflorescence. The first thumbnail probably shows best the patchy furriness around the sides, which is why the genus is called “hairy flower scarabs.” The third shows the oddly shaped antennae and that this one apparently has a very dirty head.



This paper, a pdf, by JW Campbell et al., USDA Forest Service, recounts observations of pollinating insects in various management types on land in the Blue Ridge Mountains (North Carolina). Table 2 is especially interesting. The greatest increase in pollinating insects of many families was found after mechanical shrub removal PLUS burning, but not either alone. The authors note that it’s likely that’s due to the great increase in herbaceous growth after both burning and mechanical shrub removal.

However, here’s what they have to say about pollinating beetles:

Coleoptera are considered to be the most primitive pollinators. They transport pollen by a‘‘mess and soil’’ method, in which they blunder through a flower eating pollen or nectar and defecating, so a single species of flower is rarely dependent on one beetle species for pollination.

The lion’s share of the work is done, as you might expect, by hymenopterans - bees, wasps, and ants. And so there you have it - the graceful, delicate bees and wasps - and the lumbering, messy, *primitive* beetle pollinators. We all knew that, but how gauche to come right out and say so.

(BTW, “scarab”. Does anyone remember a Twilight Zone where a nice pretty lady puts a scarab on vibrant young people and reduces them to dust? Why, it’s here! Hadn’t thought of that one in years! Amazingly, it appears that someone has put in on youtube.)

Yesterday I showed the thigmonastic response (to touch) of leaf folding in sensitive-briar.

It turns out that the same mechanism lies back of a lot of other plant movement behaviors. Seismonastic responses (to vibration) are a subset of thigmonasty, seen in the active traps of Venus flytrap plants. And nyctinastic behavior (night, or sleep movements) are also controlled by a similar mechanism.

That mechanism, ultimately, is the movement of potassium ions (K+) into and out of cells, with water following by osmosis. The result is that cells become more turgid, larger, if K+ and water move into them, and flaccid, collapsed, smaller, if K+ and water move out of them. Many of the movements of plants occur when two layers of tissue alternate simultaneously in this way, and the location of those tissues are in swollen structures called pulvini (singular = pulvinus).

In sensitive-briar, not only do the leaflets collapse, but the entire leaf branch will fall, if the stimulus is strong enough (it wasn’t in the above photo). This is controlled by a swelling similar to the pulvinus, called the major pulvis. But it’s the same stuff going on.

We really get a better handle on the plant behavior if we talk a bit about the analogous animal behavior, which is much more sophistocated and rich in possibilities. But there are similarities - it’s just that plants don’t have nervous or muscle systems and have to accomplish the same thing through different means.

As in animals, plants have to go through several stages to effect movement. They have to detect a stimulus - in animals this is done through specialized sensory neurons. In plants, it looks like certain cells have stretchy membranes that undergo membrane potential changes when mechanically stressed. In both cases action potentials are generated, and this starts everything off.

If you took an organismal biology course, or an anatomy or physiology course, then you might remember that in animals an action potential is a sudden rise in positive ions inside a neuron. It involves both potassium and sodium ions, but it’s sodium (Na+) that is the major component of the action potential. In plants it’s K+.

It’s always tempting to view the action potential as a bolt of electricity pulsing down an axon, that lengthy bit of cell that connects one neuron to the next, but it’s really a reflection of a sequential opening and closing of protein gates that specifically allow ion movements into and out of cells. This is an active and sophistocated process in animals. In plants, the movement of K+ is probably completely by diffusion, and so it’s slower and passive (but it gets the job done).

Once the signal has been generated and propagated, it then has to effect a response. In animals, the signal will proceed to the central nervous system, the spinal cord or brain, and a return signal will be sent to the appropriate muscle cell to cause it to contract.

In plants, the diffusion of K+ causes a limited number of cells (those in the pulvini) to respond by either taking water up or expelling it. The process is complicated and may include plant hormones called turgorins, which in turn cause gene expression changes, and I’m not going to go into all that. I’m going to limit myself here now to a very simple diagram that shows how a leaflet can fold up.



The top panel shows the situation pre-stimulus. The extensor cells on top of the pulvinus (or pulvis) are flaccid and small. They contain lots of sugar, and this becomes important in the next step. The flexor cells on the bottom are full of K+ and water, and are large and turguid. They’re holding the petiole up against gravity.

In the middle panel, the stimulus has been received, and the flexor cells are dumping their K+ loads out into the cell walls. Water follows by osmosis. This causes the flexor cells to become flaccid and small.

The water moves into the extensor cells by osmosis, drawn by the high concentrations of sugar. The extensor cells become large and turgid.

The result is that the petiole is depressed actively downward by the extensor cells, and this is helped along by the sudden collapse of the flaccid cells. The petiole drops and the leaflet appears to have folded up.

Meanwhile the K+ is diffusing outward along the stem and petiole branch. This is the plant’s action potential, and when it encounters the next pulvinus along the way it will stimulate that to release *its* K+, drop its leaflet, and so on down the line. How fast is this? K+ diffuses along the branch at about 5 cm per second so for one of these leaves, it takes about 2 seconds for complete foldup. This is slow compared to an animal - imagine wanting to open a door and having your hand respond 15 seconds later - but it’s a frenetic pace for a plant.

You can actually see this progressive action if you delicately touch the leaf at the base of the petiole - the leaflets will gradually drop one by one from the base to the tip of the leaf.

These are movements easily seen, but viewed really up close a plant is always in motion. The guard cells that define the stomata, those breathing holes in the leaf, are constantly collapsing and expanding, thereby closing and opening the holes upon need. The stomata are open when there’s plenty of water available, and close when the plant is water stressed, to prevent loss. The K+ mechanism controls this too.

One last thing - in most of these movements, only setting the thing up requires energy. The idea is this: for plants, it would be foolish in an emergency situation to expect that energy would be available to respond to it. So plants make sure that the response is set up to happen spontaneously, and that setup requires energy.

It takes chemical energy to pump those bottom cells full of K+ and water, and similarly for pumping up the guard cells to open up the stomata. It takes energy to make the sugar that those top pulvinar cells carry.

The actual movement, though, the closing of the stomata or the folding of the leaf, is spontaneous and rapid once it’s triggered. This is a very clever way of making sure the plant can respond to an emergency, whether it be a nibbling herbivore or a deficit of water, without having to expend energy to make that response happen.

Now most of this is my interpretation of a number of readings, but I think it’s generally accurate. There are those who know *much* more than I do about all this, and I’m certainly willing to modify the post for corrections! Some of the information came from Wikipedia’s entry on the pulvinus, a pdf on plant motor cell function and action potentials, and an article on plant cell action potentials, among several others.

Wednesday’s hike to the deck area southwest of the property netted quite a few interesting things that will occupy the attention of a few posts.

Along the way, just above the big gully below the house was Yet Another Box Turtle. I don’t find photos that match this one, so she is the seventh of 2008 and #15 of discovered living turtles.

What a sweetheart, those sad eyes.



With her faded scarred carapace and numerous scutes she looks to be fairly old. I normally count the scutes but after realizing that they always seem to fall in the range of 12-17 I gave up on this being a definitive indicator of age. Whatever the case I count at least 22 on this one, and that’s a record number.

The usual documentary thumbnails:


Right in the middle of the roadcut to the deck was this discovery, Littleleaf Sensitive-briar, Mimosa microphylla. I should mention that the genus name used to be Schrankia, as were a number of species relatives, but now Mimosa is being used.

Obviously it’s in flower now, and these are the “mimosoid” flowers typical of this subfamily of the Legume Family, Fabaceae. (And btw, TF23, that’s why they’re called faba beans (Faba is the type genus), although fava beans is a variant probably due to the close relationship between b and v.)

You’ll notice that these flowers look a lot like the hateful Mimosa Tree (Silk Tree), an introduced species ( Albizia julibrissin ). FYI, silk tree (we do call it mimosa around here, but I’m avoiding that to minimize confusion) is also in flower right now, too.

The Mimosa genus, in contrast, consists of 25 species of which only M. pudica, Shameplant, is not native (that’s arguable - USDA Plants is a little ambiguous on that). There’s a tiny possibility that this plant is that species - the expert will have to weigh in on that.


Many species in this genus exhibit thigmonastic movements, that is, movements stimulated by touch. Here’s a leaf of sensitive-briar before I touched it.


Here it is after I touched it, elapsed time, about 2 seconds.


I’ll have more to say about that later. There are other legumes, such as Sensitive Pea ( Chamaecrista spp. ), including Partridge Pea, that show a sensitivity to touch but not nearly as fabulously energetic as M. microphylla and its friends.

Yes, I take it personally. That’s what happens when you decide on January 1, just for a few days, just out of curiosity, to start noting temperatures a dozen or so times during the day. Then you enter them into an excel file, and make a plot. Then February comes along and you think, well, wonder what that looks like? By the time April has rolled around it’s become clear that to stop now would be to admit some sort of defeat and so you keep doing it. And a part of this is to make simultaneous note of the predictions, and that’s why I take it personally.

The National Weather Service *told* us that on Monday the heat would abate by 15-20 degF for the remainder of the week. Yesterday Wednesday we came within two degF of breaking the 1911 record of 103 degF. So much for the damn NWS.

(Nonetheless last night we did get some relief after three weeks without rain and temperatures scorching even for the peak of summer with two record-breaking days and a week of approaching such within a degree or two. We got rain! Two slow-moving thunderstorms developed over the county and enthusiastically engaged in ethereal fireworks for several hours, eventually dropping 0.34 inches of light rain by midnight.)

That brings us to this photograph taken yesterday. That’s Sparkleberrysprings Creek, in the same situation as it was, dry, on 29 July 2007, a full seven weeks before last year, and the second year in a row after 22 years without ever having dried up.


There are a few, remarkably few, responsible, professional individuals here who understand that the drought is continuing and that we’ve been living in an illusory local world for the last six months, a world with no more rain in the last six months than in the last two years but one softened by winter. By August people will be listening to them again, and in a combination of panic and outrage just like they were last year. But for now, I haven’t come across a single person around here who is even slightly uneasy.

Admittedly I don’t get out much, but then that’s one reason why.

We’ve seen these before, these secretive little flies. Normally I’ve found them in the deeper woods but this spring they’ve been fairly common out in the open near the house, especially in the early mornings.

They’re lauxaniids, and probably Neogriphoneura sordida comes close. They’re fairly small, perhaps 3 mm long.



There’s nothing like a nice piece of frass for breakfast, and maybe that’s where the “sordida” epithet comes from.



I’ve seen some reference to larvae and perhaps adults being predatory, and that the mouthparts are modified for piercing. I’m not so sure - they always seem to be vacuuming up the surface of leaves when I see them.


Very nice macro shot here. The photographer says that the flies were disturbed by the flash, much as the dolochids of the last couple of days. I didn’t notice that particularly.

The Eastern Pondhawks, Erythemis simplicicollis, have been unusually abundant this spring near the house. In previous years I’ve seen one or two very large ones, but only in the much later summer. The several that haunt the sunny ponds are much smaller than those but every bit as green.

Not that they have to be green in body (although apparently always green in face). Individuals in the bugguide link above can be blue, though mostly in adolescent males.


Erythemis would seem to refer to “blushing” (as in erythema). The collis part of the epithet is the latin word for “hill”, but “simple hill”?

Yesterday’s high of 102 degF beat the 1926 record by three degrees, and that’s the second record in a row. It’s not even summer yet! The good news is that last night around 9pm a couple of small and moderately intense thunderstorms formed in the area and cooled things off a bit, including dropping 0.02 inches of rain, the first since May 23.

Today was supposed to be much cooler than yesterday, beginning such a trend, but the predicted highs are right back up in the 100 deg range.

I spotted another longlegged fly yesterday, and at risk of repetition, did a little photography experiment. Yesterday’s photographs were done at 1/200 second, and most of them showed the fly in a blur as it reacted swiftly. I set the exposure time for 1/500 second for these photographs.



It’s hard to believe that in 2 milliseconds, or less, the fly has detected the flash and is up in the air.



At least 1/500 second shutter speed is capable of freezing the motion. At that speed though the light levels are really too low, even with flash, so the clarity is a little lacking.

You do remember the black spy droid rising up out of the snow in “The Empire Strikes Back”, don’t you?



This wouldn’t have worked as well with an insect that wasn’t hyperactively responsive to the flash, but with the dolichopodid it did.

Yesterday appears to have been a record-breaker, topping 101 degF and breaking the old 100 degF for June 8 1933.

In contrast to the dragonflies and craneflies this spring, real flies, with a few exceptions, have been scarce. I’ve seen only one robberfly so far.

Here is one of the exceptions. We’ve seen a fly like this before. It’s a longlegged fly, family Dolichopodidae, and like the one before it is probably in the genus Condylostylus.



They’re fairly common, and because of the metallic appearance and gaudy colors are immediately noticeable. They’re also very nervous and react instantly to the flash, much more so than any other insects I’ve photographed. Most photos are subject to at least some blurring unless I adjust the exposure time to less than 1/200 second.

This one was, like most that I see, perched atop a leaf shaded within a small tree. This was his leaf, by jove, and he was going to stay there even though every flash caused him to dance about and take a short flight before returning.



The stance and agility suggests that of a predator, but not a lot is known about what these guys eat. It’s a very large family, with lots of subfamilies and genera - this genus is probably the most colorful and metallic-looking of them all.

Temperatures reached 98F out here yesterday around 3pm. Fortunately they were down to 91F by 6pm when the pager went off for a barn structure fire over the county line (we’re mutual aid for that part of Oconee County southwest of us). Still, it was a hot two hours although our role was simply to provide water as needed. And we did a great job, communicating smoothly and arriving quickly in the tanker. The smoke was visible from several miles away.

At 5AM I was in the midst of photographing this little visitor to my computer table when the county fire channel indicated a chicken house structure fire southeast of us, in that part of Oglethorpe County. Salem, Philomath, and Maxeys VFDs were called, and we’d probably be in the next two on the list after CrawfordVFD. But it doesn’t seem to be going to happen - 911 has already 10-22’d Maxeys.

Today’s high is predicted to be 101, with no rain of course, and so looks like strong selection (in the Darwinian sense) of burn-prone structures is now in progress. Better now, I suppose, to have them removed from the firestarter pool, than later in the season when it *really* gets hot and dry.

Back to the little visitor. Our most common salticidid is Anasaitis canosa, twinflagged jumping spider, with its little white palps that wave about with great enthusiasm. We’ve seen it every month of the year, and it’s into everything. So it’s always nice to find a new one (even if it’s out of place).

This one appears to a Marpissa, perhaps M. lineata. Not that I could do a whole lot about it, but it would be nicer to have a contrasting background, not one of similar color and texture. Still you can see what’s interesting about this one - the front pair of legs. It walks about on the rear three legs and uses the front ones exclusively for signalling and perhaps sensing. Notice that the pigmentation of a middle segment on the front pair of legs is not present on the other three rearward pairs. Not much of a jumper though.

I’ve always wondered where the orb weavers we start to see in late summer come from. Of course they must come from babies somewhere but I’d not looked for them before. Here on the viburnum of the last couple of posts is just such a baby (and it is a tiny thing):


My guess here is that it’s the Neoscona, spotted orb weaver, (perhaps N. crucifera ) that I saw for the first time last October. Our usual orb weavers are marbled orb weaver, Araneus marmoreus.

The second thumbnail shows the typical posture from the front - here you can make out the black fangs.


As I was looking for info on the jumping spider, I ran across this neat paper on Spider Guilds (pdf) . It emphasizes spiders associated with crop plants. The authors do a scoring of a couple of dozens characteristics of spider predation. Those scores are sorted into groups by a clustering analysis that links families with similar scores.

Here’s a cluster diagram that shows their results. I’ve added colored dots to indicate representatives that we’ve seen here:



Not too surprisingly they find that guilds divide into web builders, and hunters that do not use webs. Of the web builders the families fall into guilds determined by the kind of web they make. The webs may be aerial (intended for the capture of flying things) or sheets (intended for the capture of falling or crawling things). Aerial webs include those built by black widows (black dot) that produce space webs (cobwebs). As well we’ve seen (red dots) tetragnathids and orb weavers, which build the marvelously symmetric webs that span spaces well above the substrate. Sheet webs include the funnel web spider of a few days ago (orange dot).

Hunting spiders can be grouped as stalkers or ambushers, and runners. We’ve seen examples of all the ambushers here: the crab and running crab spiders, and the fishing spiders (dark blue dots). The jumping spiders are not so much ambushers, as stalkers (light blue).

Of the runners the family the we see most often is Lycosidae (green dot), the wolf spiders.

I had a nourishing meal of flies prepared for today - we haven’t had flies in a long time - but then this showed up dozing on the north side of the house. No problem - we can have flies as leftovers tomorrow, they’ll be just as tasty. Looks like an Elm Sphinx, Ceratomia amyntor, and what an example of unimaginative naming it is. Maybe it’s just the lepidopterists: on bugguide there were all sorts of efforts to describe the complex banding and patterning, but nowhere did there seem to be anyone who’d done a double take and remarked “oh wow man, there’s a quaker lady on his back.” Notice the apparent absence of antennae - these popped up as soon as I’d disturbed the creature.

It’s not one of those listed in my little butterfly guide. It did not want to move its wings apart but did at least give a view of a furry abdomen with very pretty and unusual longitudinal black piping. Don’t know what all that caulking is about.


A fairly large moth, body measurement about 2.5 inches in length.


As the boring name implies, the caterpillars prefer elms. If *I* were to name the larvae I would call them Shocking Pink Babes.

I see that this moth is also called Four-horned Sphinx, and that is perhaps reflected in the genus name Ceratomia (cera=horn, as in Triceratops ). As for the amyntor epithet, this nice Discover Life writeup of the species notes that Amyntor was a Greek king. It also differs with me in my interpretation of Ceratomia (cera=gold, tomia=cutting).

Lots of fun: I ran across this very neat site, Curiosities of Biological Nomenclature, which looks like a keeper. For example:

Some names are notable for their lack of creativity:

Eucosma bobana, E. cocana, E. dodana, E. fofana, E. hohana, E. kokana, E. lolana, E. momana, E. popana, E. rorana, E. sosana, E. totana, E. vovana, E. fandana, E. gandana, E. handana, E. kandana, E. mandana, E. nandana, E. randana, E. sandana, E. tandana, E. vandana, E. wandana, E. xandana, E. yandana, E. zandana, E. nomana, E. sonomana, E. vomonana, E. womonana, E. boxeana, E. canariana, E. floridana, E. idahoana, E. miscana, E. subinvicta; Kearfott, 1907 (olethreutid moths)

This happy couple:



I’m guessing they’re craneflies (or related), and are different from the ones I’ve been mostly seeing.

I’ve been able to recognize at least a half-dozen different cranefly species this spring, although I haven’t been able to identify most of them. I’ve mentioned already that they’ve been extremely abundant this year, but that’s just one of the things that I find fascinating about them. They’re also just extremely weird-looking. And I imagine, particularly when so abundant, that they’re a huge foodsource for arthropod and avian predators. The larvae, too, which burrow in the ground, must be attractive to a lot of insectivores: armadillos, yes, well ok, them too.

Craneflies are flies, of course, in the order Diptera. They’re members of a nontaxonomic group (the “Nematocera”) which includes at least five infraorders ( Bugguide. Note that Bugguide is limited to the US and Canada.) One is the phantom craneflies, one is the hanging flies, one even includes the mosquitos. I’ve had people tell me that craneflies are just giant mosquitos (not entirely a bad way of looking at it) and that they’ll bite you (not true).

The positioning of this pair deep within the foliage meant I couldn’t get a good top view, and it turns out that that means I missed recording some important diagnostic features. I couldn’t tell whether there were three ocelli, for instance, and that’s fairly important knowledge. The wing venation is also important, as is the antennal shape and emergence position.

One thing that doesn’t seem to be important is that these have their wings folded over their backs at rest, instead of spread out. Of the five families of cranefly or cranefly-like types listed in Bugguide within the infraorder Tipulamorpha, there look to be representative genera in each one with folded wings, so it’s not a great character.

At least I know I need a good dorsal and head view next time!


And, oh yes, the high today predicted to 97 degF. Same for tomorrow and Sunday. Yesterday it was 98 degF, a high of 94 was predicted. No rain until Mon or Tue at the earliest, and none in the last two weeks. Grim.

Yesterday I posted a bristly larva that has been abundant around here, and suggested it was a Giant Leopard Moth, Hypercompe scribona, although there were problems with correspondence of coloration. Bev suggested it was a Virgin Tiger Moth, Grammia virgo, and I agree. That’s a much closer match for the larvae. Looks like at some point we ought to have a lot of adults around.

A few years ago we planted a number of native Viburnum species, and some have grown to be quite large indeed. They’re hosting a number of visitors these days, and yesterday I found these striking little (about 1 cm long) caterpillars nibbling away (and pooping, as well):


The little horn on the tail is pretty striking. You’d think that would be diagnostic, and probably it is to an already expert, but search for horned caterpillars and all you get are sphinx moths. Which is not what this is.


Enter the Hostplants and Caterpillars Database, which often works very nicely to provide some clues, especially when the identification is more obscure. I put in Viburnum for the hostplant genus, USA for the location, and got back 46 entries. Apparently lots of things like Viburnums. Searching for photos of caterpillars on Bugguide got me a very likely match for the larva of Oreta rosea, Rose Hooktip.

There are very few photographs (I found only one, googling) of the larval stage. There are tons of adult photos, though, as it is a fairly striking moth. This might be a good one to try to raise, not for conservation purposes, but because all the parameters - food, hypothetical species, and so forth - are all in line.

This is probably worth mentioning, particularly for those in the southeast.

For the the last six weeks I’ve been amazed at the number of these caterpillars walking about. I’ve seen them in every environment, from deep in the moister forest area to upland sunny areas - they’re everywhere. I recall seeing them last year a few times, but certainly not in these numbers.

I’m guessing them to be the larvae of the Giant Leopard Moth, Hypercompe scribonia, but if you look at those images (you may have to select “caterpillars” to see the larvae) you’ll notice that the vast majority have red banding. This one does not, not even when it curls up into a ball when disturbed.

UPDATE: Bev suggests Grammia virgo, Virgin Tiger Moth, and I agree. It’s a much better match and the red pigmentation is not present.



It’s not just this individual - I’ve yet to see one around here that shows distinctive red or orange banding or spotting. I’m figuring there is just a large variation in extent of pigmentation but if you think it’s a different species, by all means say so!

That white spotting, btw, is just where each patch of bristles emerges:


Regardless, it is almost certainly in the Tiger Moth family, the Arctiidae, notable for the bristly appearance of the larvae. Hostplants Database shows quite a number and range of families of plants that appeal to Hypercompe: citrus, euphorbs, sunflowers, honeysuckle, magnolia (and presumably tulip poplar), plantain, willow. What I don’t see around here is an unusually large abundance of any of these plants, at least none that wasn’t present last year. So perhaps last year’s drought effectively drove away birds or other predators, allowing more adults to survive and reproduce. Whatever the reason it’s probably worth noting that I have no photographs of leopard moth adults on the blog!

As for the name origin, I’m fairly stumped. Hyper is over and beyond, of course, and there are no small numbers of choices of derivatives that might be applied to compe. One likely possibility is compos, meaning in possession of. The scribonia epithet would seem to have to do with writing, or a writer. How all that fits together is anyone’s guess - maybe it has to do with the distinctive markings on the adult.

It may be silly to express surprise that it’s already June 3 - it was, after all, on the calendar and everything - but still. Is it already June? Gracious! If we didn’t know anything about calendars we’d still be forewarned: ca 90 degF highs, 20% chance of afternoon thundershowers every day for the foreseeable future. That means it isn’t going to happen, btw.

The cuddeback wildlife cam continues to deliver photos and I continue to place it in various places. It takes wonderful photos of deer. Deer at night, deer in the daytime, deer peering into the camera, deer bounding across the field of view. It seldom comes up with anything different.

Here’s something a little different, and it’s the only photo - the bird was just walking out of field of view in the 30 second movie that followed, so that was useless. The scene is Goulding Creek in the background, just beyond that concentration of trees. The time stamp is correct. This bird is pecking along the old roadcut that runs down to the creek.


A blowup of the relevant portion. I’m guessing this to be a wild turkey (which we do have) although it seems a little small for that and there was no evidence of more birds (which doesn’t mean they weren’t around). The head looks a little odd for a turkey but it’s mostly a blur so could be misleading.

Anyway, I’m going to throw it up in case anyone automatically recognizes it for something else.

I remarked earlier in May that this had been a wonderful spring for us. How wonderful was it for you?

From the National Weather Service Climate Prediction Center, this is a plot of mean temperature anomalies for the US. That’s the difference in the average temperature for this May above or below the average for May over many years, plotted in colors. The anomalies are in Fahrenheit.


The big story is clearly the much colder than normal temperatures throughout the north central US. The northeast US and Great Lakes took a turn, after a couple of months of warmer than usual, to cooler than normal temperatures, quite a bit warmer than normal along and east of the great lakes. The US midsection continued to experience colder than normal temperatures. The Pacific northwest was just a bit cooler than normal this May. The southeast was uniformly warmer over the month of May but this was not a great anomaly except for a swatch covering Alabama, southern Mississippi, and southeast Texas.

From the (click through to the monitoring maps from the left sidebar) National Weather Service Climate Prediction Center, this is a plot of mean precipitation anomalies for the US over the month of May:


The US midsection, Montana, and Wyoming had a surplus of rain in May, much as they did in March and April. So did Arizona and much of southern California, combined with much colder temperatures. Despite the colder temperatures though, the north central and northeast US was drier than normal. Florida took a hit with a dry May, combined with somewhat warmer than average temperatures. The rest of the southeast was a mixed bag, but the confluence of GA, SC, NC, and TN generally saw lower than average rainfall.

For Athens:

The above figures show that we had slightly warmer temperatures and below average rainfall during May. We continued our second month without a single fire call, in May. Once again I closed out the NFIRS incident reporting for the month with 9999999, no activity, other than the usual exemplary training sessions, of course.

Here is my plot of high temperatures for the month of May in Athens. As usual, the black dots are for the 17 years 1990-2006 (black dots), 2008 (green line), and 2007 (red line).


About all that can be said about our May temperatures was that they were remarkably mild and even. We didn’t break 90 degF until May 31, and that was the only day that was outside one standard deviation from the mean. There were 4 nights of temperatures cooler than one standard deviation from the mean, but there are usually 5.4 such nights, on average.

Athens saw only 2.33 inches of rain in May, and combined with the 3.00 inches in April completed a dry spring, with only 68% of the rain expected (1920-present). Out here in Wolfskin we had 2.90 inches. According to the official analysis, Athens averages 3.86 inches in May, and that’s what I get for the time period 1920-present. However since 1990 the average has been 2.86 inches, which parallels the decline in rainfall we also see for April in the last 18 years. And so that’s why the green line for this May looks fairly good with respect to the red average - that’s the average since 1990. It wouldn’t look nearly so good if I plotted the average since 1920.

And so April and May both, in the last 17 years, have become much drier than they used to be, with only about 75% of the rainfall over the 17-year period, when compared to the 87-year period. This spring we had a total of 8.81 inches of rain, compared to an average of 11.18 inches (1990-2000) and 13.01 inches (1920-present).


I can see this in the state of our two creeks, which sample different areas. While still flowing, they are clearly down in the last few weeks. Vegetation is lush, and that evapotranspiration rate, which must be enormous, has placed an added stress on an already extremely low 2007 reservoir replenished poorly during the winter and spring.

I’ll continue to link to this neat prognosticator in which you can get variously timed precipitation and temperature outlooks, but here is the May 15 prediction for Jun-Jul-Aug:


Now that’s a probability picture, and it’s a 3-month outlook centered on July. White areas are those that have an equal chance (EC) of being either normal or abnormal. The colored areas have greater chances of being abnormal than of being normal, and the color and intensity indicate in which direction and how skewed the probability of abnormality is.

So, for instance, for us in Georgia, we have a greater probability of cooler temperatures this summer, while the western US has a greater probability of being warmer than usual. For precipitation, the northwest US is more likely to be dry, and the Gulf Coast states are more likely to be wetter than usual (yes, I know it was a dry month for Florida). The northeast US has a higher probability of warmer and wetter temperatures this summer. In Georgia we have an equal chance of above or below average rainfall.

And who can complain about that? I crave a cool summer with normal chances of a good thunderstorm every few days.

Geekstuff:
NOAA’s weekly ENSO update is at last slanted toward predicting a return to ENSO-neutral conditions sometime in the summer. The sea surface temperatures have increased a bit but we are still under La Niña conditions. This is the tenth month of La Niña conditions in the Pacific.

Finally, and to reiterate the link way above, NOAA has a neat State of the Climate product. By clicking on the year, such as 2007, you can get to monthly and even weekly reports and zero in on regional descriptions that are much nicer than my own.

Yesterday we finally broke 90 degF, with a hot, dry and breezy 92 degF for a couple of hours. And it looks like the rest of the week will have highs in the 90s as well, so it seems that we are moving into summer, with only 2.9 inches of rain under belts for May.

Who could have known that I would find this handsome large dragonfly on my walk yesterday? I almost didn’t go in that direction, but there it was sitting in wait on a fallen tree trunk on the bank above Goulding Creek.


I used the wing venation to eliminate skimmers and eventually to decide that this is probably Tachopteryx thoreyi, Gray Petaltail. It may be gray, but it’s also a wonderful shade of violet.

It’s found in the eastern US, north into Canada, but it’s also mentioned as uncommon, endangered, species of concern, in Ohio, New Jersey, New York, Michigan - basically the northern part of its range. There is one account of a population that no longer exists because of development. This isn’t a species that takes kindly to encroachment. There are scattered observations in Georgia.

Most dragonfly nymphs are aquatic. The nymphs of this species apparently live in the mud of clean seeps. So I guess we have clean, spotless mud, and therefore a population of something approaching a bioindicator species. Of course, *Bev* or *Doug* are probably going to say it’s a common blue skimmer or something and my hopes will be dashed . But I don’t think so.


The genus name looks like a combination of tacho, speed or swift, and pteryx, wing or feather. Well, all right then, but fast wings pretty much describes any dragonfly, right? The specific epithet comes from G. Thorey, an insect trader in Germany in the 19th century.

I see that this family, the Petaluridae, is among the most primitive of dragonflies. Primitive doesn’t mean clunky or old-fashioned or out-of-date in biological terms - it means closest in appearance to the ancestor. Not that it is the ancestor. The idea of primitive and advanced evolutionary characters is a useful one, but doesn’t really map to the impression that kind of language suggests.