Monday, December 21, 2015

Winter Solstice 2015

The short, sunny winter day in the desert ends with beautiful warm lights and deep shadows. It's easy for our dogs to make us go for a sunset walk. Above is the view south across our property with Wassem Peak and Saguaro National Park West in the background.

Looking north, through State Trust Land with many Saguaros and even more Chollas into the flat spread of Avra Valley.

On our fence waits a little fly catcher that I haven't seen here before. Maybe a Wood Peewee? Wild guess. Too bad that with two impatient dogs in one hand and the camera in the other, and very little light, the focus is off.

Ants are still active, but dragging their tarsi. Veromessor pergandei, harvesting the seeds of those November-blooming Chinch Weeds I think.

Frodo heard the song of his Coyote relatives and took off to find them. But he eventually returned tired and panting while the choir kept serenading us. Or maybe they were just inspired by some sirens on the freeway.

One of our Great Horned Owls took off from a branch right above my head ans landed not too far from us, not afraid of humans or dogs.  The light was now really getting bad. 

Getting closer and going down on the ground, I could get him against the lighter sky ...

Using the little built-in flash also turned out less than ideal ..  Too bad, because the guy was endlessly patient.

The sky was now getting dramatic - and Saguaro silhouettes do set it off perfectly.

The best colors over Kitt Peak and Ragged Top in the Northwest across Ironwood National Monument. It's nice to live right in the middle of two great parks!.

Happy Winter Solstice to all on the northern half of the world!

Thursday, December 10, 2015

The colors of arthropods

Evolution has produced many outrageously colorful arthopods. The driving factor may have been communication, intraspecific to attract partners or interspecific to warn or deceive predators.
Many patterns and color combinations that appear out-standing when seen out of context may be very cryptic on the right, natural background. Pigments also protect underlying tissues from radiation damage and play a role in thermoregulation.

Colors of arthropods can be based on several different phenomena:

 Transparent epithelia that allow  hemolymph or inner organs be visible and therefore to determine the outer appearance. The abdomen of a mosquito is red shortly after a blood meal, and some spiders adopt the color of their prey if they feed on highly pigmented insects. They 'become what they eat', for a short time.

Crab Spiders of the genus Mecaphesa can adjust their color to their surroundings
Many colors of arthropods are based on organic pigments that are embedded into the exoskeleton or cell layers directly underneath it. These pigmental colors are based on the partial absorption of light. The pigments (carotenoids, ommochroms, flavenoids, quinones, etc) are obtained from food and sequestered or products of the insect's metabolism, often by- or waste-products, and their stability is based on the animal's living, active metabolism. Some arthropods have the ability to change these colors actively (Crab Spiders, Tortoise Beetles). Pigment based colors typically change or fade after death. 

Pair of  Deloyala lecontei which occurs in 2 color morphs
 Structural colors are either based on the selective refraction of reflected light by the exoskeleton or by living cell layers directly under a transparent cuticle. I cannot find definite explanations of the mechanism, but these refracting elements in the latter seem to consist of layers of lipid droplets. 
One individual of Jonthonota mexicana undergoing color change due to disturbance
 Many tortoise beetles are able to control these refractors, effectively switching from a bright gold metallic to a dull brown or red appearance.

The permanently metallic appearance of many other insects is created by the unique structural arrangements of many dozens of layers of exo-skeletal chitin. The cuticle, which is just 10 millionths of a meter deep, has some 70 separate layers of chitin—a nitrogen-containing complex sugar that creates the hard outer skeleton. All these layers have different refractive indices.
Calosoms scrutator (Carabidae)
 Incoming white light (sun light) is refracted through—and reflected by—each interface giving, in particular, phase differences in the emerging reflected rays. For several wavelengths in the visible range, there are many reflected rays whose phase differences allow for constructive interference. This leads to the metallic appearance of the the insects. The resulting colors are called 'structural' as opposed to 'pigmentary'. These structural colors outlast the death of the insect. (Loosely quoted from  "Visible light reflection spectra from cuticle layered materials," by Cristian Campos-Fernández, Daniel E. Azofeifa, Marcela Hernández-Jiménez, Adams Ruiz-Ruiz  and William E. Vargas  Optical Materials Express).
Chrysina aurigans
 The cited study was concerned with Costa Rican Scarabs that appear golden all over. 
 Very shiny beetles like those may blend in with the multitude of dew or rain drops sparkling on the foliage around them, especially in the dim light of the tropical rain forest. 

Chrysina gloriosa on juniper
Metallic patterns on  parts of larger bodies may also break up the larger shape and hide it that way. I have noticed this for example in beetles and caterpillars that live in the lacy foliage of mesquite or juniper. Seen from below, against the light, these insects are less visible than their non-reflecting relatives.

Chrysis sp. Chrysididae (Cuckoo Wasps)
 Does the metallic appearance of the exoskeleton  indeed indicate a certain hardness and armament of the wearer? Several parasitic bees that seem to get into scuffles with their host species  appear particularly metallic.

Pipevine Swallowtail - the iridescence will outlast death

 Not to forget: The colors of butterfly wings are also structural, even if they do not usually appear metallic due to the small size of the colorful sub-units, the scales. In some species, however, the arrangement of the scales is such that iridescence is achieved. At the U of A, studies are under way, looking into the importance of these direction dependent flashes of color in the partner choices of our Pipevine Swallowtail.   

Wednesday, November 25, 2015

Through the Grasslands of Santa Cruz County

I love those grey-golden expanses of grass that role and wave under the low standing winter sun, and those mountain ranges with names like Mule and Mustang that cast their deep shadows. So when I had to deliver art work to my little Patagonia gallery (Creative Spirits Artists) I took my time on southbound Highway 83. I did not stop for every Hawk that perched on the power lines, but a whole heard of Pronghorns was too good. There were at least two dozens of them, grazing not too far from the road side.

 I even swung around to go back. Of course, shortly later several more cars and a motor cycle with blaring music stopped too.  Most of the people saw the pronghorns for the first time, and their questions made me realize that I don't know a lot about these attractive mammals either - I see them in open grassland towards New Mexico, around Prescott Valley and around Sonoita (yesterday's heard) and once I saw a big mixed group - Half Mule deer and half Pronghorns in the Watson Lake area of Yavapai County. I knew that at 50 miles per hour they are  the speediest US mammals, and I just learned that they are also great long distance runners.

Both sexes carry horns with the name-giving prongs. These horns are composed of a slender, laterally flattened blade of bone that grows from the frontal bones of the skull, forming a permanent core. As in the Giraffidae, skin covers the bony cores, but in the pronghorn, it develops into a keratinous sheath which is shed and regrown on an annual basis.

Like deer and other even-toed hoofed animals, pronghorns chew their regurgitated cud. This enables them to live on a diet of grasses, sage, cactus and other hard-to-digest plants of the steppe, often including plants unpalatable or toxic to domestic livestock. 

They fill an ecological niche very similar to that of the Antelopes of the old world whom they resemble physically and behaviorally. So they are often called 'Pronghorn Antelopes'. But the similarity is mostly  based on convergent evolution. Zoologically they are the last representatives of the family Antilocapridae.

 I was asked if they are native.  Yes, they are but some groups have been moved around to repopulate parts of their natural range. Are they wild or owned and put on those fenced pastures? Yes, wild and able to move across those fences. But I thought that they might jump, like deer. Apparently, they rather go under the obstacle. For this reason, the Arizona Antelope Foundation and others are in the process of removing the bottom barbed wire from the fences, and/or installing a barbless bottom wire.

Pronghorns seemed to be close to extinction around the turn of the twentieths century. Their number had been decimated by over-hunting, habitat loss, break-up of their migration paths, and sheep-transmitted diseases (blue tongue disease). Protection and management have helped most populations to recover. But the  Populations of the Sonoran pronghorn in Arizona (and Mexico) are still endangered  and  protected under the Endangered Species Act (since 1967). 

Tuesday, November 17, 2015

Birds and weather at the Fountain Hills Art Show, November 2015

The Fountain Festival in Fountain Hills, Arizona, takes place along the artificial lake of 'the Tallest Fountain of the Planet'. I'm always looking for winter guests, the customer kind at the show and the avian kind on the water. I like those Hooded Mergansers. In the afternoon, when I had no camera with me, they were displaying and vocalizing around their females, a great spectacle.

Blue Heron, Great Egret, Night Herons and Cormorants were sleeping in a mesquite tree on an island. They are smart to seek that safe haven. I found the feathers of several coots on the bank of the lake, and in the morning we ran right into a very wet bobcat that strolled leisurely across the road, ignoring several close-by dogs. He must have known that in FH, they take their leash-laws awfully seriously.

A young Night Heron got hungry and tried to fish - I guess the mergansers and grebes would not be there inf the lake was as sterile as it looks?

I think these are Eared Grebes, I have seen also Western and Pied-billed ones there. Fish-eaters all, I believe. There were also 5 smallish gulls that I could not identify. Bonaparte Gulls maybe.  Herons and Cormorants usually only come for the night, they spend the day at Salt and Verde River.

On Friday and Saturday, the weather was beautifully sunny and warm. Show weather that makes you remember why the Arizona the outdoor show season is in winter. But on Sunday morning, the sky looked ominous. By noon it was raining on and off, later it poured and the gutters begun flooding the back of our tents. Luckily, the front of my tent consists of clear see-through material with a door, and it stayed inviting enough for shoppers to step in out of the rain. I need to take some photos, next time.

Wednesday, November 11, 2015

The 'Spider Poster' is ready!

The Arizona Arachnid Poster is now ready to be printed. For posters I don't use my own Giclee Printer, because the inks are too expensive for mass production. Instead, I'm ordering from a company that specializes in posters. So I have to make sure to order enough at a time, at least 10, better yet 20 or 30. It's looking good, the orders are coming in.

This was the old post, showing how the poster came together, slowly:
I am working on a new poster: Spiders and other Arachnids of Arizona. It won't be ready for Halloween, but it is not meant to become a short lived spooky decoration anyway. Rather it's supposed to show the beauty of spiders and maybe raise some interest in this fascinating group. So here is a teaser - 15 of about 50 images are placed so far, but they can still be moved around some.

I will also again make a black and white template with the species names that I'll send out by e mail - to everyone who orders this poster. The size will be 18 by 24 inches to match the Arizona Beetle Poster. It will cost $35 plus shipping. You can order by e mail or message me on my Facebook page. I will add new images here as I progress.

I am also printing greeting cards. The will be available for the first time at the Fountain Festival in Fountain Hills this weekend.

Tuesday, November 3, 2015

A last Hurrah of the Desert Broom shrubs in Madera Canyon

On the first of November I went back to Madera Canyon and found just a few of the Desert Broom bushes still blooming. The weather was perfect this time: sunny and not particularly windy.
Many more butterflies than last time congregated mainly on the few male shrubs that still had something to offer.

Apodemia palmeri (Palmer's Metalmark)

Anthanassa texana (Texan Crescent)
Hemiargus ceraunus

Asterocampa leilia (Empress Leilia on a female shrub

Libytheana carinenta (American Snout )
Vanessa cardui (Painted Lady)
Junonia coenia (Common Buckeye)
Atlides halesus (Great Purple Hairstreak)
Chlorostrymon simaethis (Silver-Banded Hairstreak)
This green Silver-banded HS was a first for me, so I asked my friends Mary Kinkel and Fred Heath for confirmation and background info. Mary confirmed that we have a pretty 'good flight' of these pretty guys this year.
Fred wrote: The Silver-banded Hairstreak uses Balloon Vine (Cardiospermum sp?). This plant is  a rare and very local plant in extreme southern AZ. It is found in some local gardens, for example the Arizona-Sonora Desert Museum where I’ve found a few Silver-banded in the last couple of years. There may be more than we know locally , but the local botanists have not found it. There is also the possibility that they are using something else locally. The Soapberry and Hopbush, two common plants here are in the same family, but do not have the same type of hollow fruit with the seeds inside which the caterpillars are known to eat. Jim Brock says it wouldn’t surprise him if they are using something altogether different. Interestingly, Jim Brock and Bill Beck have Balloon Vines in their gardens and have found Ceraunus Blue caterpillars happily feeding on them. I guess the butterflies just don’t read the books.
Fred Heath

Friday, October 30, 2015

Stormy Weather!

We had a mostly golden October with a Cinch Weed carpet covering the desert floor, and temperatures reaching back up into the nineties over the weekend.

 So both my art shows, one in Patagonia and one last weekend at Phillips Plaza in Tucson  had excellent weather, great customers and artists huddling in a few shady spaces.

But yesterday our temperatures in Arizona dropped!
It's cold and wet, with snow flurries in the mountains and lightning storms. Breakfast on the patio at below 50 degrees, Jacket weather!
We measured 2.71 inches of rain in our gauge for this month, the most for any October since we moved here in 2002.

Wednesday, October 28, 2015

Arachnid Poster

I am working on a new poster: Spiders and other Arachnids of Arizona. It won't be ready for Halloween, but it is not meant to become a short lived spooky decoration anyway. Rather it's supposed to show the beauty of spiders and maybe raise some interest in this fascinating group. So here is a teaser - 15 of about 50 images are placed so far, but they can still be moved around some.

I will also again make a black and white template with the species names that I'll send out by e mail - to everyone who orders this poster. The size will be 18 by 24 inches to match the Arizona Beetle Poster. It will cost $20 plus shipping. You can order by e mail or message me on my Facebook page. I will add new images here as I progress.

Monday, October 26, 2015

A potentially deadly trap

Nearly too well camouflaged for his own good: trapped Diamondback
 At least it could have been. Luckily Randy spotted a rattler this morning and called me to bring my camera. Looking more closely, we found that 'our' big Diamondback had crawled into a chicken wire cage and got stuck. The wire had been used to protect young plants, but we learned a while ago that it can be fatal to all kinds of reptiles who get stuck in it. So the fences were out of commission and should be stored out of reach, but a recent windstorm had blown stuff all over the place.

So I got a long-handled pair of clippers - but it only served to bend the loop away from the snake's body. He still couldn't get out. So we had to get closer. He's a very strong, big snake. I remember his powerful writhing from the only time I had to move him - an unsettling experience even though I'm used to lifting snakes with hooks or tongs.

A noose-stick is no tool to lift a heavy snake, but it keeps the head securely under control so I could cut the wire
 This time we used our old noose-stick. Not a tool to lift a delicately boned snake, but quite safe for holding the head in place. So Randy held him and I got the wire cutters. It wasn't difficult, the snake held still and slid out of the wire fence unharmed.

He immediately rearranged his coils and stared indignantly, but stayed in place for a while before slithering off. I'm sure we'll see more of him, he's been a regular visitor to our patio for months.  We were lucky that we found him early in the morning of a cloudy, rather mild day. Direct sun exposure kills a snake in no time because they have to depend entirely on behavioral thermoregulation.