Monday, January 28, 2013

July, 2011

Here is a continuation of my review of 2011. The month of July.

The month begins with some interesting caterpillars. The first is a Walnut Caterpillar. It's a quite wonderful hairy thing.

These feed on the leaves of walnut and pecan and other types of nut trees. They often appear in a tree by the dozens or hundreds clustered fairly closely together. They have an amazing defense maneuver. When some predator approaches, the individual caterpillar twitches its body violently about once a second. No one knows how they coordinate this, but every caterpillar in the tree begins the body twitch, and they do it in exact synchrony, so that instead of each one looking like a vulnerable and helpless creature, it looks like they are all one big breathing animal. I suspect it might frighten off a bird. But when we have come over to watch this behavior closely, it has usually been parasitic ichneumon wasps attacking them, and the wasps didn't seem to be very impressed.

But the next caterpillar is our absolute favorite of all. It's called The Laugher, and this picture will show you why.

Look at the horrible "teeth" from close up. This guy's been on crystal meths half his life.

Here's another of the dozen or so bumble bee-mimicking robber flies in the genus Laphria that are found in Arkansas. This is Laphria lata.

Plains Clubtail, female, Gomphus externus.

The robber fly Ommatius ouachitensis, eating a midge.  Both these creatures have feathery antennae.

The male of the Zabulon Skipper is a small bright yellow and orange butterfly that sets up a territory and drives off everything, including you, that comes too close. The dowdy brown female is the opposite in personality, slipping around quietly down in the shadows. But looked at closely, as here, she is pretty in her own way.

Here's another special caterpillar, the Spiny Oak-Slug, Euclea delphinii.  These atypical moth caterpillars have no legs but slip around sort of like slugs. They are cute, but don't touch. They are armed with stinging spines.

Argiope aurantia, the Black-and-yellow Garden Spider, with a large katydid.

This fancy wasp has a fancy name, Gnamptopelta obsidianator. The larvae are internal parasites of caterpillars.

 Here's a Spot-winged Glider, Pantala hymenaea. On warm days these and their near relatives, the Wandering Gliders, can fill the sky with their swarms.

Promachus fitchii, a handsome robber fly of prairies.

A Seaside Grasshopper disappearing into its background.

Efferia aestuans, female, a rather natty robber fly. Females of the genus Efferia feature long ovipositors.

The robber fly Holcocephala, sometimes called the Goggle Eye. This species is in the subfamily Trigonomiminae, and though there is some debate on this, this is possibly the basic robber fly group from which all other robber flies derive.

Trapdoor Spiders, big black tarantula-like spiders, spend most of their time waiting inside a tube just below the surface of the ground. When some insect comes jauntily strolling by, they suddenly raise the lid of the carefully concealed trap door, rush out, grab the hapless insect, and drag it struggling back down underground, and close the trap door behind them. It all happens so quickly you think you've only imagined it, and if witnessed, is the arachnophobe's nightmare come true. We saw this trapdoor spider during one of its occasional wanderings above ground.

This is a Dusky Dancer, Argia translata, a damselfly with beautiful violet eyes.

Here is the female ovipositing her eggs in the water, the male holding onto her with claspers on the end of his abdomen. He is not bravely protecting her from drowning, he's just keeping a hold on her so no other males try to get in on the act.

A large powerful dragonfly, the Gray Petaltail, Tachopteryx thoreyi, killing a big grasshopper. Dragonflies are among the most primitive insects, and this is the most primitive species of dragonfly.

The Powdered Dancer, Argia moesta, gets its name because as it gets older it gets more covered by a powdery bloom which renders its pattern indistinct.

The Red-legged Grasshopper, Melanoplus femurrubrum (the red is on the hind legs so you can't see it here), is a member of one of the main subfamilies of grasshoppers, the "Spurthroats." The picture shows, between the front pair of legs, the "spur" for which they are named.  But while we are looking at this close-up, notice something else: Insects evidently evolved from a centipede-like creature that had many segments, and a pair of legs on each segment. As insects developed, they collapsed the number of segments into fewer but more complex parts, and did away with all but six legs. But sometimes the legs, instead of disappearing, were co-opted into other jobs. You can easily see here two pairs of what once were legs are arranged around the mouth and are now used to help shovel in food.

This nice moth is the Rose Hooktip, Oreta rosea.

And this one is Harris's Three-spot, presumably named for the three gold spots on each forewing.

The well named Handsome Grasshopper, male, and (even handsomer) female.

Argiope, with some of her husbands (we've seen up to eight) hanging around her.

Here is the robber fly Triorla interrupta again, this time having caught a large and very fierce dragonfly, the Eastern Pondhawk.

A very early instar mantis, and a very early instar Northern Green-striped Grasshopper.

Rabidosa rabida, a big wolf spider.

A bagworm with an especially stylish bag.

And finally, to close out the month of July, this subtly handsome caterpillar of the Virginia Creeper Sphinx, Darapsa myron.

Thursday, January 24, 2013

Spontaneous generation

The ancients believed that if you set out a carcass or a pile of dung, after a period of days it would spontaneously create a swarm of flies. I think Aristotle was among the first to stop and actually observe what was going on, and he found flies mating and laying eggs in the usual way of procreation.

I'm no longer certain he was right. For instance, earlier this month when the days were particularly overcast and cold and rainy and icy, and it was difficult to find any invertebrate stirrings of life, I got up after a rainy night (.60 of an inch of rain in my rain gauge) and went to my study in an outbuilding in our backyard. The rain off the roof of the building had left a pool outside the door, and the surface of the water was black with tiny living things. These were springtails, tiny (1 to 2 mm) wingless creatures with six legs that formerly were thought to be primitive insects, but now are thought to be their own kind of six-legged thing. They are, evidently, super-abundant everywhere, on water, on snow, but especially in dirt. If you pick up a handful of soil and examine it closely, you will see tiny little things walking around.

I pointed out this black-covered puddle to Cheryl, and she stood back and looked at the building and showed me that what I had thought was splattered mud on the walls was actually springtails covering every inch of the front of building up to a height of some five feet. They looked like they might have been grazing the algae on the walls. If we were real scientists we might have picked a representative square foot, counted every nearly microscopic dot on it, then extrapolated to the number of square feet that they covered, and finally have gotten something like the actual number present. But since we are "naturalists" rather than "scientists," we were happy to say, oh, hundreds of thousands.

Cheryl took some pictures of them, I made a note in my records. We came out the next morning, and they were gone without a trace.

Wednesday, January 16, 2013

June, 2011

Here is a continuation of my review of 2011. The month of June.

Sulphur-tipped Clubtail, Gomphus militaris, male. This species barely enters the SW corner of Arkansas, and is one of the many species Charles Mills was first to discover in the state from his very strategic center of operations at Lake Millwood. Cheryl and I found this one just to the north in Grandview Prairie.

A bright and pretty Phaon Crescent.

Double-striped Bluet, Enallagma basidens, male.

Checkered Setwing, Dythemis fugax, immature.

Spangled Skimmer, Libellula cyanea. I like the bright headlights on this one. Dragonflies, with their long stiff wings, are always picking up bits of web floating in the air.

Prince Baskettail, Epitheca princeps, female. Here's another species that flies by the hour over water and never lands to give you a chance to photograph it. But we have discovered that on very hot days they eventually begin to overheat, and go deep into shady woods to cool off.

Here below is an adult male, with bright green eyes. Look how nicely its color and pattern blend into the dappled light and dark.

Sawflies are very primitive wasps whose larvae feed on plant material and look just like small moth or butterfly caterpillars feeding on leaves. The larvae tend to be gregarious and can strip leaves at an incredible pace.

Here is the head of a dragonfly (a Blue Dasher, Pachydiplax longipennis). That "smile" is the last thing many small flying insects see. Note the thousands of lenses on the wrap-around eyes.

Jade Clubtail, Arigomphus submedianus, male. This is the second of the three Arigomphus species in the state (I showed a picture of the blue-eyed Stillwater Clubtail, A. lentulus, in the preceding blog). This one features green eyes, and a red tail. One more to go. But the last one is scarce.

Jade Clubtails mating.

Royal River Cruiser (Macromia taeniolata), immature female.

Tufted Bird-dropping Moth caterpillar, Cerma cerintha.

Tufted Bird-dropping Moth, Cerma cerintha. A number of moths are patterned to resemble inedible bird droppings when they are landed.

A powerful robber fly, Triorla interrupta, eating a katydid.

Here is a more formal portrait of a Jade Clubtail.

And of a Spangled Skimmer.

And of a Widow Skimmer, Libellula luctuosa.

This very small wasp has paralyzed a jumping spider several times bulkier than it is and is lugging it vertically up the front wall of my house to a cell it has made inside the eaves. It will secrete it there and lay an egg on it. I think the confrontation between these two is, for its size, the equal of the dramatic confrontations between tarantulas and the giant Pepsis wasps that attack them.

Cloudless Sulphur caterpillar, yellow form.

White-dotted Prominent caterpillar.

The black instead of red at the end of the abdomen shows that this, after a long search, is the male of the Bayou Clubtail (A. maxwelli), the third and scarcest of the Arigomphus dragonflies.

Here below is a female Bayou Clubtail (A. maxwelli), with immediately following, for direct contrast, a female Jade Clubtail (A. submedianus).

That was for me a nice ending for the month of June.