Thursday, February 26, 2015

One more thing.

Here's another way I've been spending the dreary cold days.

For the past several years Cheryl and I have been cataloging the insects and spiders of Crowley's Ridge, the anomalous small range of hills which runs by our house in the northeast corner of Arkansas. We have kept photographic records for the Ridge, and of course as we have traveled to other parts of the state we have been taking pictures of everything we saw, since that is our pleasure. But I have been putting specifically the Crowley's Ridge photos on Picasa Web albums (The Butterflies of Crowley's Ridge, the Dragonflies of Crowley's Ridge, etc.) and arranging them as photographic field guides, hoping they might be useful to people learning Arkansas insects.

Well it occurs to me that by now we have taken images of most of the butterflies in the state as a whole. The major ones I am missing are the irruptives that every few years come just across the Texas border into the Lake Millwood area. They are all common Texas species that we know quite well from traveling there, and it didn't seem worth it for us to drive all the way to Lake Millwood just to say we have seen them in Arkansas. We have images of these species that we have taken in Texas, so I decided I could just add them in and make a new set of albums, and call them "Butterflies of Arkansas." We have about 130 species, which is as many species as anyone is likely to see in
state. We are missing nine species that are considered to be regularly occurring, though very rare (we'll make it a goal this summer to look for them, and that will get us out in some parts of the state we are not very familiar with).

So what I am saying is, I have been passing a few days in my study splicing pictures together and creating this new collection of field guides, THE BUTTERFLIES OF ARKANSAS, which I have put on five albums and I am just this moment making them public. Here they are, in case you might be interested.

Butterflies of Arkansas (I): Swallowtails and Whites and Yellows

Butterflies of Arkansas (II): Gossamerwings and Metalmarks

Butterflies of Arkansas (III): Nymphalids

Butterflies of Arkansas (IV): Spreadwing Skippers

 Butterflies of Arkansas (V): Grass Skippers

Sunday, February 22, 2015

Well, something else to do in the winter.

In my last blog I stated with casual certainty that winter was now over. It's pretty clear I offended the weather gods.

So I'm back to figuring out things to do when the weather is so bad its not worth going out of the house. I'm back to trying to take pictures of birds. I think as a modest endeavor I would like to do portraits of the common birds in our garden. This is hardly photography of the kind where you set up a hide in an area rich with exotic birds, leave it up for a few days for the birds to get used to, then go before daylight accompanied by a friend who, after you crawl into the cramped and uncomfortable and bitterly cold hide will walk away so that birds (so long as they aren't ravens), being unable to count, will see someone leaving and think the coast is clear. That's how my heroes did it when I was growing up.

No, I'm of the new school who sits at my dining room window with a cup of coffee and my digital camera lying on the table in front of me, and when a bird comes by I start clicking pictures of it through the double-panes.

The first one I see is a female cardinal. They can be just as attractive as the males in their quieter and more tasteful way. But this one is kind of blowsy, letting it all hang out. I decide it's a throwaway.

The next one is a blue jay, which poses nicely, sort of like a dog stretching out in front, an invitation to play.

But the picture is too dark. Those blues on the wings and tail should be brilliant, the colors on the back rich shades of purple. I don't know anything about the technical aspects of photography, but I believe the problem is this: The camera is exposing the picture for the brilliant white of the snow, but that leaves the dark bird underexposed. So I use my adjustment button and move it towards overexposure, and that brings out more accurate (or at least, prettier) colors on the bird. While I am at it, I dodge out most of the seeds lying around, which give away the fact that these are bird-feeder shots, kind of cheating. The snow now makes a nice uncluttered background.

That's better, I think. But I see I still have to take out that silly black streak above the bird's head. And since I am fiddling with it again, I can't resist pushing the exposure even further. Here's where I end up:

Now parts of the bird are overexposed. I can no longer, for instance, see the white undertail coverts against the snow. But lots more detail has come out around the eyes, and the blue spots on the wings and tail have come up even more. The general color of the bird is truer, I believe.

But I'm thinking, bird photography is a mug's game. There are so many brilliant bird photographers around now that each species has been recorded with every feather barb showing, every scintillance of reflective color, every aspect of behavior, to where there is no point taking another picture of that species.  It seems like there is no opening left to do something new or something better. In this past couple of years when I have been trying to take some bird pictures, I am discovering how many really excellent photographers there are just here in Arkansas, whose most casual snapshots seem to get a brightness and depth and clarity I can't equal. Is it because they have better equipment? ("It's a poor carpenter who blames his tools," Cheryl's father used to say.)

In the midst of these thoughts a very handsome Eastern Towhee jumped up on a tree branch before me. He was jerking his head around, flirting his tail. But staying at the same spot for a few moments. I started clicking pictures of him as fast as I could, hoping to catch him in a good pose. But I was out of synch with him. I would see in the view finder a good head angle, and click a picture of him just as he left that position. I finally made myself stop and I waited. There was the view I wanted: He was looking directly at me with his wild red eye. He stayed just long enough for me to get the picture.

Now I was happy, all my doleful thoughts gone. I was ready to compete with the others now. They might have got the eagles locking talons in mid-air, but they didn't get this common species sitting on this ordinary branch in my front yard.

And anyway, the moment it warms up I'll get back to taking pictures of spiders and insects, where the field still isn't as crowded as bird photography.

Saturday, January 24, 2015

Something to do in winter

One gloomy drizzly day after another. And then finally a very cold but at least clear sunny day. That was a week or so ago. It was what we were waiting for: With that good light, maybe we could go look for raptors and try to take some pictures of them. I put the long lens on my camera, we packed the cooler with peanut-butter sandwiches, filled our thermos cups with coffee, and drove southeast from Jonesboro to Wapanocca National Wildlife Refuge, near the Mississippi River.

It was totally empty of people, a big wildlife refuge just for us. Constant flights of geese were going over, white-fronted, snows, Ross's, heading for the lake in the center of the refuge. We headed there too and walked out onto a long fishing pier. There were thousands of ducks out there, almost all mallards (we had read that mallards had a very good breeding year on the prairie potholes this past summer). We must have made them nervous as they quietly moved off to another part of the lake, revealing as they did so the huge raft of geese out in the center of the lake, and stretching the length of the lake. Here were tens of thousands of birds.

Their murmuring and yammering was constant, and then suddenly it went up several decibels and the geese burst into the air like the explosion of an atomic bomb filled with confetti (clearly going beyond my ability to form a metaphor). Maybe I should just settle for saying it was one of the great sights in nature, equal I think to the courtship flights of flamingos in African soda lakes, or the autumn flights of shearwaters along the Pacific coast,  or the blackbirds flying from every point of the compass into multimillion-bird winter roosts.

When the air cleared a bit, we saw the culprits who had caused it, a couple of "white-belly" (second year) bald eagles had flown directly overhead. Here's a not very good snapshot of one of them.

Before we left the pier I happened to look down in the water close to us, still thinly frozen over, and was surprised to see two predacious diving beetles swimming under the ice. There were also a couple of water boatmen (the little bugs that are like backswimmers right-side-up). Don't ask me what they were doing there, but when I got home and read up on it, it turns out it was not unusual behavior, at least for the beetles (Brian Baldwin tells me they have been seen active under a foot of ice).

And when we walked over frozen leaf litter, tiny wolf spiders were racing along ahead of us. Is there no time of year when they are not active?

Now we began driving the levee road down one of the refuge's canals, the sun behind us. Cheryl drove slowly while I sat in the passenger seat, window open, camera pointed down into the canal. The car makes a good blind, and birds pretty much ignore it as long as you keep moving. The moment the car stops and you point that big eye directly at them, they take off. We drove along hoping to find a bird that would remain behind for at least a moment, to give us a chance for some reasonably close shots. We got lucky with some hooded mergansers, birds in equal parts handsome and comical, especially the females with their Marge Simpson hairdos.

There were a few red-shouldered hawks beginning to call, the initial signs of courtship, that premonition that spring was somewhere in the offing. One handsome bird flew out of the woods and landed on a tree over the canal. Cheryl eased to a stop, cut the engine, and the bird, which had been facing us, turned to the side, leaned out, and took off. But by good luck it hung poised just long enough for me to get a desperate snap.

Then gloomy winter closed in again. But we had a feeling its back was broken. The trees were beginning to flower, the bald cypress had their long tassels, bees were finding the first flowers sheltered in among last year's fallen leaves.

Friday, December 5, 2014

2 bird feeders 1500 miles apart

Cheryl and I spent the week over Thanksgiving with our son Gawain and his girlfriend Heather at their home in Tucson. We visited our favorite places, the Desert Museum, Saguaro East, Catalina State Park, Mt. Lemmon, Sweetwater Wetlands, various gardens and so on. At night they wined and dined us with wonderful meals at home and at various of the endless supply of first-class ethnic restaurants. In other words, it was our usual visit.

But at quiet times during the day I sat in the back yard and observed their bird feeders. We had just begun getting our own feeders up and running in Jonesboro, in the NE corner of Arkansas, some 1500 miles (nearly half a continent) away, and I found myself comparing the two. A garden with bird feeders is, after all, a specific kind of habitat with characteristic birds. Our feeders and theirs are, I suppose, in suburban gardens, theirs in the middle of a large but very green city in the southwest, ours on the outer edge of a small city in the mid south. I wasn't comparing them in terms of which was best or had the most species, but in terms of seeing how the fauna changes as you travel east to west. What I noticed was, the birds I saw in Tucson were not very different from ours: Essentially the same birds were present, but each species had shifted over one space.

Some birds were exactly the same. For instance, we had a daily flock of mourning doves, they had a daily flock of mourning doves. Occasionally a small flock of white-crowned sparrows came by both places, but not often, as the vegetation in both our gardens was too tall for their liking.

But, as I say, most of the species had shifted over to the nearest western version. For instance, American goldfinches are a major component of our feeder in Jonesboro. Here in Tucson, it was lesser goldfinches.

Because they are more towards the center of town than we are, they have an invasive introduced species we do not have in our garden, house sparrows.

Since we seldom see them, or look at them when we do see them, I had the novelty here of noticing what handsome little birds the males are. In Britain, where ours come from, they are a part of the natural fauna, and for unknown reasons they (along with starlings) are slowly disappearing. We may one day be in a position to reintroduce them to Britain from our unwanted stocks.

Filling this bird's position back in Jonesboro, we have an invasive introduced species of our own, the house finch. When we moved to Jonesboro in the mid 70's, the very first house finches were appearing in Arkansas. I think we may actually have driven into town once to get a glimpse of one. Now they are numerous. The story we all hear is that a pet shop in New York had brought some out from the west coast to sell as cage birds, and a few had escaped, and from that tiny beginning began spreading west. They have since joined back up with the original west coast birds somewhere in the middle. The house finches in Tucson are not introduced but were there all along, no doubt nesting around the dwellings of the paleo-indians adding color and cheerful songs to their lives. They are the commonest birds at the Tucson feeder, and I fancied these "real" birds looked different from ours in Jonesboro, though I don't know in precisely what way. Something subtle in the color perhaps.

Our brightly colored and patterned eastern towhee was replaced in this garden by Abert's towhee, a bird that ran along the ground like a mouse, staying in the shadows. It's an elegant bird, but like so many birds that are western versions of their eastern counterparts, the colors and patterns are subdued to be more in keeping with desert colors.

A bigger more dramatic bird also racing about mostly in the shadows, the curve-billed thrasher is the desert-colored version of our richly colored and patterned brown thrasher. It would bound up on the feeding table with its muscular body, glare around with its fiery eye, then grasp a peanut and dive back into the tangle of palms and cactus at the back of the yard.

Our noisy red-bellied woodpecker, which comes to suet cakes and (awkwardly) to our hummingbird feeder, is replaced here by the closely related and even more noisy gila woodpecker. The gila sweeps in for a peanut and is gone too quickly to be able to get a decent picture of.

Instead of the ruby-throated hummingbird that comes to our feeder, in Tucson it is the Anna's.

At our home in Jonesboro in winter the tiny tame ruby-crowned kinglet is constantly flitting around the garden searching along every branch or under every leaf for tiny bits of protein. In Tucson filling the same niche was the tiny tame verdin.

And just as at our feeder, in Tucson a heavy presence hangs over the scene. Every time a bird picks up a seed it stops to look all around before looking down for the next seed. At the least movement of a limb, at the sudden shadow of a large bird, all the birds are up with an audible rush of wings. Scarcely a full minute goes by without that rushing sound. The cooper's hawk is a common nesting bird in Tucson (as it is becoming in Jonesboro), and their visits came at least once a day. The birds dive into the thicket, the hawk dives in right behind them, and the success rate is high.

But minutes later the surviving birds are back feeding again. I sometimes think, how can the birds lead a normal life knowing that if they go even ten seconds without looking around they could be violently killed? Why aren't they entirely stressed out? How can they eat, court, feed young birds? But sometimes someone can come up with an analogy which makes these impossible to conceive of questions suddenly comprehensible. My favorite example is the person who said the movement of tectonic plates is making the Atlantic Ocean spread "at the speed that fingernails grow." My wife came up with one of these analogies. When I said, What must it be like to live when you can't ever relax your attention for more than a few seconds? she said, "It would be like driving."

I thought about that, making the long drive back to Jonesboro, snacking, drinking coffee, talking, listening to music, marveling at the scenery, at the same time that multi-thousand pound semis hurtled by us inches away at eighty miles an hour.

Saturday, November 8, 2014

What do entomologists do?

To tell the truth, we spend quite a lot of time examining male genitalia. It's often the only sure way to identify invertebrates. When two closely related invertebrates evolve forms far enough apart that they can no longer mate with one another (often because the parts no longer fit together), that is one of the definitions that they are separate species. We've been working for the last few years on a photographic field guide to the grasshoppers of Arkansas, trying to make the guide like a bird field guide, that is, making the species identifiable by sight, by field marks that are visible through binoculars, or from close-up photographs blown up on a screen. In other words, so they won't need to be caught and examined under  a dissecting microscope.

You would think that would get me away from all this close attention to genitalia, but actually all it has done is make it more complicated. Now I need to find ways to make the free and untrammeled creature expose its genitalia to me, and I have to get myself into whatever weird angle I need to photograph it from so I can examine it at my leisure on my computer screen.

I've gotten quite good at photographing grasshoppers so that they reveal all (and grasshoppers are surprisingly modest). But this summer I convinced myself I was being a coward by only recording grasshoppers, and not all the other Orthopters, the crickets and katydids. Katydids always seemed to me especially daunting, endless identical green things with long skinny legs and antennae. Capinera's "Field Guide to Grasshoppers, Katydids, and Crickets of the U.S." actually has pages of sonograms for the katydids and crickets, suggesting that since they are out at night and are famous for their camouflage, the only practical way to know which species are around is to listen for their songs. The problem is, at my age most of the high-end bird songs are gone, and I expect I am missing a lot of the katydid and cricket songs as well.

Well, this summer I started on those other orthoptera and I have made some progress, but at the moment I am back to genitalia. There are a few genera of katydids, for example (like Orchelimum or Scudderia) where all the species in the genus look more or less identical to each other. In those cases, the species write-ups in Capinera are presenting me (just as with the grasshoppers) pages of diagrams of genitals.

To show you how it works, here is a male katydid in the genus Orchelimum.

If you note the thing like a carrot sticking out of its rear end, that is one of its cerci (there's another one on the  other side) which it uses to hold the female in place while they are mating. The different species have differently shaped cerci. Here's the chart in Capinera.

What I have to do now is sort of stand on my head so I can get a better angle on the cerci.

And then get in close for a detail shot. (A slight problem is, I am seeing them from below, and the chart shows them from above.)

I have checked the range maps, and luckily only four of the species on the chart (marked by a black dot) are known to occur in Arkansas. Now if you look at the chart, of those marked ones only the second one on the top row, and the first one on the bottom row have the slender unlumpy shape of the katydid in my photograph. Of those two, only the top one has the spur shorter than the remainder of the cercal shaft, the bottom one showing the spur to be longer. Therefore my picture is of O. agile, the Agile Meadow Katydid.

I'm showing you all this to show you how it works. Actually, on this species I am using as an example, there is a simpler way of identifying it: It has a white head and orange-yellow tibiae (the second long joint of the leg). Of the four possible species in my area, only O. agile and one other species, The Black-legged Meadow Katydid (O. nigripes), has a white head, and you can probably guess how the Black-legged differs from the Agile.

This is the only species in our area with black tibiae, so in this case even the female (as here, with her ovipositor) is readily identifiable.

That's two of the four that are found here. Here is a third species.

This has a green head, which means it cannot be one of the first two we looked at. It looks to me like the spur is longer than the rest of the shaft after the spur, which makes it O. silvaticum, the Long-spurred Meadow Katydid.

There is a fourth species, The Common Meadow Katydid, O. vulgare. I think in my heart this is it:

But I can't prove it. I was so intent on photographing it in the act of stridulating, with the "arched wings making a megaphone," as David Ferguson expressed it, that I forgot to get the cerci into the picture.

There are three katydids in the genus Scudderia that occur in Arkansas, all pretty much identical in appearance. Here is Scudderia texensis, the Texas Bush Katydid.

I have shown you a female because this is one of the rare cases where the female is much easier than the male to identify to species. If you look at the ovipositor, the upper margin of the base, and the upper margin of the terminal portion are at right angles to each other. This is true of S. texensis only, females of other species in this genus having a wider angle. But there is no simple way to identify males.

Here is a male Scudderia, found in the same area as the above, with similar coloring, and is very likely also S. texensis, but I can't prove it, since I didn't get a look at the genitalia.

 To identify males, once more I have to examine a chart.

The picture at the top of the chart shows how the rear end of a male Scudderia looks from the side. The six pictures below it show how the sort of tongue-like structure on the top would appear if you were looking straight down on it. The shape at the tip is vital for identification. The three Scudderia species that occur in Arkansas are: On the top row left, S. texensis, Texas Bush Katydid; top row right, S. furcatus, Fork-tailed Bush Katydid; and bottom row left, S. curvicauda, Curve-tailed Bush Katydid.

Now if you look at the live unrestrained katydid in the picture above the chart you will see the problem: All that equipment is permanently concealed beneath its wings.

Here's how we're trying to get around this problem: We were out a couple of days ago and saw a male Scudderia.

I quietly positioned myself behind and a little below him while Cheryl took a long stick and used it to gently lift his wings, and we got these rather rude pictures.

The green thing curving up is what they call the "ventral abdominal process" and the reddish thing it  meets is the "dorsal abdominal process." We see that the dorsal process is bifurcated into two deeply cleft forks with rather meaty side pieces, and the chart tells us this makes it the Fork-tailed Bush Katydid (top row right).

Now I just have to hope the police never search my computer for pornography.

Thursday, October 9, 2014

Take another look at that bumble bee

[This essay appeared in abbreviated form in a recent issue of the Arkansas State Audubon Society Newsletter.]

We easily recognize that this is a bumble bee. It's a large black and yellow insect with a furry yellow thorax with a bald spot in the middle of it. We might feel kindly towards this big bumbling creature visiting our flowers, but if I said "Pick it up, please," you would quickly hide your hand behind your back.

Do you realize instinct has helped to program your response, that you have responded in much the same way a bird or lizard or even many insects might have? What we are responding to is the color and the pattern on its back. Black and yellow are warning colors, they signal to us and other creatures that this thing either tastes bad or bites or stings. Black and yellow bands on a yellow jacket send the same message but not the same--What do I want to say?--trustworthiness. We're wary of yellow jackets; we know the bumble bee is completely inoffensive unless we try to pick it up, and the difference is that round yellow thorax with the black spot in the middle.

Now, lots of harmless insects that are very good eating would like to have the bumble bee's dangerous reputation, as it might discourage predators from attacking. In fact a surprisingly large number of insects imitate the bumble bee as closely as they can manage, for just that purpose. I'll show you here just a few.

Most of you recognize this first bumble bee mimic, the Snowberry Clearwing. It's a very common day-flying hawk moth that hovers before your flowers drinking nectar through its long tongue, its wings an invisible blur, looking like a small hummingbird. When it emerges from the pupa into adulthood it has brown scales covering its wings, and the thorax is covered with yellow fur. But almost instantly it begins shedding scales from its wings until they appear mostly transparent (as on a bumble bee), and the bald spot begins (as here on this fresh individual) to appear on its thorax. The strategy must do it some good; this is one of the commonest creatures in our garden.

You probably don't recognize this creature as a bumble bee mimic. This is an American Carrion Beetle, a common visitor to road-kill corpses (don't confuse its name with the endangered American Burying Beetle). The one in the picture is on the back of a dead opossum. Here on the corpse it doesn't seem much like a bumble bee. It doesn't have a furry thorax, which would just get bloody and messy. But, it has a pretending yellow furry thorax, with a pretending bald spot in the center. I didn't think it was a very good disguise, until one day I saw one flying swiftly to a road kill, following the scent trail. It was buzzing loudly like a bee and sweeping around at about eye height (also like a bee) and looked so much like a bumble bee I had to look and look to be sure it was a beetle, and I have a lot of experience with these mimics.

I've shown you so far a moth and a beetle as bumble bee mimics. This one is a fly, Laphria affinis. In the genus Laphria there are dozens of species, the great majority being bumble bee mimics. They carry the mimicry to a high art, and they are such a successful group that I am sure they get the full advantage of looking like something with a painful sting, which they do not have.

But here the discussion gets complicated. So far I have shown harmless creatures pretending to be dangerous. But this Laphria really is dangerous. It's a robber fly, a powerful killer of other insects, using, not a stinger, but a beak which injects neurotoxins and digestive enzymes that kill quickly and turn the insides of its prey into soup, which it sucks up its hollow beak. If you try to pick this one up he'll stab you and you won't forget it. They wait in an open place, and if a suitable prey insect flies over, they fly up like a falcon and snatch it out of the air, too fast sometimes for you to see.

So is it possible that this one relies on the other part of the bumble bee's reputation, the reputation for inoffensiveness, in order to cosy up to the creatures it is hunting? There is defensive mimicry, and offensive mimicry. Or at least there is a hotly contested theory that some mimicry is predatory in intent.

I was always skeptical of that second theory. For one thing, it is axiomatic that robber flies very seldom visit flowers, and if you see one landed on a flower it is probably a coincidence. So how is it going to cosy up to insects that hang out in the same places that bumble bees do, namely flowers?

Well it was this very species, Laphria affinis, that I one day saw bumbling and buzzing clumsily around some big sprays of flowers, often stopping to hang from them as if he were interested in their pollen.

I happened to have an insect ecology class with me and I was explaining this theory to them, and how skeptical I was of it. A number of orange soldier beetles were visiting the flowers paying no more attention to the big fly than they were to the real bumble bees also there, and before we knew it, he had one.

Here maybe I had better show a pair of mating Laphria thoracica (a different species of robber fly), to prove that at least they can tell each other from bumble bees.

I've led you carefully from step to step to help you see what I see in a remarkable horse fly I found yesterday drinking sap from a tree wound. I saw from a distance what looked to my practiced eye like the old familiar pattern. Here was a rather large stout all black insect with the yellow thorax with the bald spot in the middle. This group of flies in the genus Tabanus have a stereotyped pattern of close-together black stripes on the thorax, perhaps very difficult to alter. But horse flies I'm sure you have noticed have marvelous eyes of all colors and patterns of green or red or green-banded and so on. The males have eyes all the way across the top of their heads with thousands of lenses, and the patterns come from the light refraction from differently shaped deep-down lenses. This is where the different species get a chance to differ from each other, and it may only require a few genes to make the alteration. I think this fly has not only created a pretending bumble bee thorax, it has created a pretending thorax itself, out of its eyes. I have never seen the like before, and I can't seem to find anything like this in my books or in BugGuide (though, interestingly, I found a west-coast Tabanus that had evolved an actual furry-yellow thorax with a bald spot), and I wonder if anyone has seen this fly before and seen the bumble bee pattern, or if it is only my fascination with insect mimicry that has made me imagine it. I looked at it from different angles to see if the pattern held or was just an odd quirk from my angle of vision, and the pattern held.