Tuesday, May 7, 2013

Monstrous!


I'm going to be out of the country for a short while without access to my blog, I expect. So this is an opportunity to publish a few short blogs that were planned but not executed before. For example, when I found those big Bot Flies in Sabino Canyon they exited me and a very select few of my entomologist friends to the point, that a much more popular monster was left by the wayside. Literally: just watch him walking along.

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Our Gila Monsters were unusually visible this year, at least in Sabino Canyon. For several weeks the Group of the Friends of Sabino Canyon met on or two on each of their Wednesday hikes. No idea whether it was the same individual that took a liking to the group? I think the monsters are rather oblivious of people. Mostly they want food at this time. After all, they spend most of the year under ground, hiding from drought and food shortage between the rainy seasons.
When they are out, they gobble up whole clutches of quail eggs,  whole litters of rat pinkies...I once surprised one that was chewing down a whole rather grown-up pack rat. This venomous lizard  (the only  in the US) has to chew with their formidable jaws to release venom along a grove in their teeth.

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On the lower jaw of my friend here you can see the big, bulging glands. Although I didn't get my nose too close to him, after all, Gila Monsters are said to suddenly lunge, bite, and then hold on for good, I noticed a peculiar chemical smell -  ok, all smells are chemical, but his perfume seemed nearly inorganic: a little like chlorine in a pool...   A pheromone? It is mating season.

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 The smell of his poisonous droolings? But he wasn't drooling. He was only testing the air with his forked purple tongue. He was certainly not interested in me or my hiking boot standing between him and whatever he had to do before going into hiding once more.

Friday, May 3, 2013

The background is most important

Western Corsair, Rasahus biguttatus
The Western Corsair is an impressive Assassin Bug. He is fast, nicely marked, night-active, and a hunter of other insects. He runs them down, paralyzes them with his poisonous bite and sucks up their liquified tissues.

But there is something else in the picture that is at least as important as this predator for the ecosystem that we call desert: the cryptobiotic soil crust, those dark green specks he is walking on.

The spots are communities of cyanobacteria, green algae, lichens, mosses, liverworts, and other microorganisms that colonize the surface of bare soil.  "Cryptobiotic" means "hidden life."  This crusts in our backyard goes mostly unnoticed. and does not even look alive when it is very dry (as it usually is).  When it rains enough, though, the crust looks greener and more three-dimensional, like many little mounds of moss. There are more impressive and well studied examples in moister shaded areas in many national parks. But this unassuming variaty that covers the drier desert habitats may be of special importance and is probably the most fragile.

Haboob over Eloy AZ
 The crust is vital to the health of soils and ecosystems.
It holds the soil in place and protects underlying sediments from erosion. Lately we have seen our mountains disappear behind dust clouds that were blown in all the way from the Californian desert were agricultural use has laid the soil bare. Last year haboob clouds rose up horrifyingly from the Phoenix area. The thin living layer that covers undisturbed desert soil can prevent many of these events, but it is very fragile. Agriculture, development, motor vehicles, even grazing cattle will destroy it. Also, I am not sure how the current ongoing drought conditions will impact it. Once disturbed it may take decades for the fragile system to grow back to its former productivity, even under 'normal' weather conditions.

Where the layer is intact it can be the first start of organic soil development on bare inorganic sediments, absorbing water and, through photosynthesis and fixation of atmospheric nitrogen, enriching the surface with nutrients and organic matter. This in turn creates a favorable environment for seeds to germinate and for insects and other soil organisms to live. For more info and great photos go to this link.


Here in the arid Southwest we are learning the hard way that this fragile, living component  of our soil deserves diligent protection. As a kid in Germany I would not have thought that I would ever come to value this kind of ground cover so much. I remember that there was a particularly shady area in the yard behind my grandmother's house where we were not supposed to play because the ground was slimy and green and to our mothers 'full of germs' (these were the sixties). But I did see my first liverworts (probably Marchantia sp.) there and marveled at their shapeless not-quite-floral not-quite-fungal existence that sometimes did give hints of a higher organization. Even at four years old (the house was sold when I was five) it peaked my curiosity.   

Wednesday, May 1, 2013

First sightings for this year

Yes, I know. The first of May is a funny date to start this attempt to record some phenological data for our area in SE Arizona. I think there is still enough of my northern European upbringing in me to feel that this date is special. I will try to begin every month with a little summary of the season's best observations that haven't made it into a blog of their own.

So here goes:
Iron Cross Beetles, Tegrodera aloga, in Sabino Canyon, April 27 2013, Photo by Ned Harris
All week in Sabino Canyon we found big groups of mating and feeding Iron Cross Beetles. Most of them congregated around nearly dried up Whooly Star plants.

Gambel's Quail, Callipepla gambelii, with chicks
Yesterday, April 30, the first very tiny baby Gambel's Quail. The parents made such a ruckus that I actually went and checked whether it was a snake alarm. But eventually they coaxed some very young chicks out of the brush, so I knew what the excitement was about.

Centris pallida on Ironwood and Centris rhodopus on White Ratanay
The first Saguaros bloom and the first Ironwoods are covered in pink. The deep humm of Centris bees can be heard from a distance. Centri pallida visits the leguminous trees, the flowers of the White Ratany and Creosote are attracting the darker Centris rhodopus.



Mesquite flowers in Saguaro National Park West are covered in mating Netwing Beetles of the genus Lucaina, and the first Lycus sanguinea showed up, too. No group leks for this species.

Creosote Bush Katydid, Insara covilleae, nymph
I also found a very camouflaged last instar nymph of the Creosote Bush Katydid, Insara covilleae, feeding, as it should, on creosote leaves.

Enallagma civile (Familiar Bluet)
At a pond at the Desert Museum, another nymph had just left its old skin and its former element behind to spread its wings as a Damsel Fly. But first it had to patiently wait until its teneral paleness transformed itself into the beautiful color of an adult Bluet.


Today: May 1, the first Lesser Nighthawk swooped out of his hiding spot in a Palo Verde in the State Land. In the evening they were courting, a pair gracefully dancing over our backyard while continuously making a sound like a melodious purr.

White-throated Swifts Aeronautes saxatalis) adapted from a photo by Alexander Viduetski
 In the morning four White-throated Swifts were also very active over our yard, but their shrill, twittering calls drove the dogs crazy and their ballet soon deteriorated into a wing-on-wing battle, with two of them (a couple, two males??) tumbling repeatedly all the way to the ground. I had never before seen them do anything but catch bugs so high above that they seemed to belong to another reality...not earthbound as they suddenly seemed. The things we do for sex...


Prickly Pear Cacti and Chollas are in full bloom. The flowers are full of Diadasia bees, the digger bees that are specialised on cactus flowers.

Little swarm of feral, Africanized Honey Bees. The wandering swarm (left) is very peaceful and approachable. The one that found a cavity in the saguaro will build a hive there and then may get aggressively territorial
This year we seem to have fewer feral Honey Bees than usual. Our Africanized version is not as freeze tolerant as the European stock (that's why they never became a problem in Europe and further north in the US, just here in the Southwest where the winters are usually warm). The species is otherwise very robust and there are enough bees left to increasetheir population again to compete with our native bees.

Male Black-tailed Gnatcatcher
From my studio window I'm watching the antics of four or five fledgling Black-tailed Gnatcatchers. They are probably learning to glean the Palo Verde tree for small caterpillars of the Palo Verde Looper.

Palo Verde Looper, Faculta inequalis


The adult moths are coming to my black-light at night where they are eagerly awaited by several small Red-spotted Toads who were joined last night by the first huge Sonoran Desert Toad.

Western Banded Gecko, Coleonyx variegatus
I have never seen a Banded Gecko this big and colorful. I think he must be in his mating-season best!