Tuesday, March 29, 2011

A tiny Parasitoid Wasp on Campus

There are only small patches of planted,  native vegetation on the University of Arizona campus. I don't know whether that is because of a great old arboretum that used to take up most of the campus area - many of the old trees have made room for building expansions by now, and the last freeze killed a number of others - or if there is an attempt to match the old fashioned red brick buildings with fresh green lawns and ivy....

But if you offer just a few yellow flowers (Desert Marigolds) and budding prickly pears with extrafloral nectaries, the bees and wasps will come.

On the fat Santa Rita Opuntia pads, washed lavishly in silver, turquois  and hot pink, a little speck of yellow and black stands out. It's only about 4 mm long, and in the glare of the mid-day sun I have to take a macro photo to get a better look.

The tiny abdomen, huge hind femurs and sickel-shaped tibiae tell me that it is a male chalcid wasp of the genus Conura. Against hope it is identified quickly on Bug Guide by Ross Hill as C. side (Walker 1843).

Most Chalcid wasps are parasitoids of other insects. They lay their eggs into eggs or larvae of Butterflies, Beetles, Flies, True Bugs, Spiders, and even some Nematodes (Worms). Their larvae develop in the living host, but the host usually dies when the chalcid larvae break through the skin to pupate externally. Chalcid wasp distribution covers the holoarctic as well as the tropics. The genus Conura is most widespread in the tropics.
 Chalcidoidea are ecologically important, morphologically and biologically extremely divers, and phyllogenetically very challenging. With 60, 000 to 100,000 species and a worldwide geographic range they will keep researchers busy for a long time. To learn more go to the Chalcid site on line which offers lots of information.

Monday, March 28, 2011

Carpet Beetle Anthrenus sophonisba

Anthrenus sophonisba

While photographing dozens of  interesting bee species on the Brittle bushes around our patio, I found a beetle that I hadn't seen before on a cholla branch. You can see it smaller than the areoles of the cactus, less than 4 mm long. Its compact round shape, tiny clubbed antennae and the dense, attractively patterned scale covering identified it as a member of the Genus Anthrenus in the family Dermestidae. Typical is also the ability to withdraw all appendices into a tight pill shape. These beetles are also called Skin or Carpet beetles. They could be named Collection bugs as well. While the adults can be found on flowers feeding on pollen, the larvae feed on all kinds of organic material like wool, stored food, hides, and insects in collections.

Dorsal and ventral view of the beetle playing dead

 Checking the family page for Dermestidae on BugGuide.net and Andreas Herrmann's excellent online resource for dermestid species I quickly got to the species A. sophonisba.  Surprisingly, the attached author name Beal 1998 indicates that the species was only described 13 years ago. I have no access to distribution data other than Bugguide and some mentioning of the species when I google it. All point to western locations, mostly in California. It's amazing how many insect species are still being discovered and/or described every year in the Western United States.

Those pretty scales are fragile. By the time I'm done with my photos the beetle sadly shows some  wear. But I did get one good shot for my digital collection of Arizona beetles that will hopefully one day mature into a field guide.

  I wonder whether I should digitally straighten that right middle leg or leave it like this - after all, my beetles are alive when I take my photos.
However, this one is going into the freezer now. Being too small to be pinned, it will be glued to a point of archival paper. An insect pin will keep this point and the labels with the collection data together to make this carpet beetle a useful part of a research collection, unlike his feared, destructive brethren.

Thursday, March 24, 2011

Curve-billed Trashers Rule!

Cuve-billed Trashers have many talents. They whistle at you like a street kid. They have a beautifully varied song that I like at least as much as that of the Mockingbird. They build a nest in the middle of a jumping cholla protected by thousands of barbed thorns, but are said to clip off the thorns that could hurt the nestlings. They are great parents that never tire of their very noisy, demanding fledgelings.   
But they are as fierce and aggressive as their yellow eyes and their sharp profiles promise.

A couple of years ago I watched this fight among a Trasher and a Gilded Flicker. Flickers are our largest woodpeckers here in the desert, and they easily drive the smaller Gila Woodpeckers from feeders and nesting sites. Luckily for the Gilas, there aren't very many pairs of Flickers. But in the case of Trasher against Flicker, the Trasher won.

But you have to watch what happens if a Trasher wants to impress his girl (and I don't think I' m anthropomorphizing very much here - shared aggression is a form of pair-bonding that can be observed in many species). Curiously, he never attacked the smaller Round-tailed Ground Squirrel, but he took on the giant Rock Squirrel every time the big guy tried to stuff his cheeks. When I filmed this, the squirrel was already a little desensitized to the attacks and seems to mimic a skunk, so the Trasher walks off, finds a new strategy and.....Just watch it.

The original video shows how the female thrasher joined the triumphant male after his victory of the quail block. Unluckily, the flickr version cuts off just before she arrives.  

Anyway, here they are, sole owners of the quail block of contention.

Monday, March 21, 2011

Coyote Crossing

 One my way home from the University I often leave the busy freeway (I10) to travel west on Silverbell, a road that winds its way between the Santa Cruz River on the north side and the Tucson Mountains on the south side. It's less romantic than it sounds, because the river smell bad from the release of treated waste water and the banks are pockmarked by gravel mining and cruising off-road vehicles.   But there is wildlife: Hawks are nesting precariously on power poles,  ducks and herons fly overhead, and today I first slowed down for a roadrunner, then for a coyote trying to cross the road. 

In fact, because there were many cars behind me, I first blocked her progress by pulling up next to her. She wasn't too happy - it shows in her expression. I never turned off the engine and kept the windows closed.  She relaxed and waited around until I got my camera out of its bag and focused, and all the other cars had passed. Then she took up her original direction again, crossing the road, leaping elegantly over a substantial fence on the other side, and off towards the Tucson Mountains. Good luck!

Our Coyotes here in the desert are small, only about 35 pounds. The packs usually consist of a pair and a couple of last years pups. The desert just doesn't feed larger groups. From coyote scat one can tell what they eat: everything. There is bunny fur, bones of little rodents, though most will be dissolved by strong stomach acids. Pieces of mesquite or other fabaceae beans that are in season. Bird seeds, berries, lots of pinacate beetle shells. They do grab cats and small dogs if they can. 

Our dogs are at fifty to sixty pounds much larger than coyotes. We used to have an invisible electric fence to keep our dogs  in about one acre of our back yard, the rest was left to a group of  resident coyotes, usually three of them.  During full moon nights, the male appeared outside the dog run to challenge Cody, our male dog, who just loved to play along. For hours I'd listen to: Yep-yep-yep-wheoouuuuh! Wow, Wow, Wowowowow!!!! Yep-yep-yep-wheoouuuuh, Wow, Wow, Wowowowow!!!! endlessly repeated. The females, a husky and a wolf-dog, and on the other side probably the coyote bitch, stood back admiringly. Sleeping? impossible. The contestants had found the best acoustics closest to the house. So I got up, with a flash light (for the snakes) and joined Cody. Mr. Coyote was only 15 feet away, clearly visible in the moonlight, but safely on the other side of the invisible fence that controlled the dog. He ignored my requests to leave and sing elsewhere. He scoffed at me clapping my hands. So I crossed the line of the invisible fence. He put back his ears, kept staring. Unbelieving. Made grunting noises. Another step. His tail went down. Tucked between his legs. Unhurriedly, he backed of. Melted into the surroundings. Was gone. For now. I was my dogs' hero! For now - forever. They are dogs! 

Cody, Montana, and Laika
When my dogs meet coyotes on walks (outside the dogs' direct territory) I often see them pointedly looking the other way when they have to pass each other. A strange dog would cause a happy chase or a fight, but the coyotes seem to enjoy a truce.

Sunday, March 20, 2011

Local Birds, Exotic Plants

When we bought our desert property in August of 2002, there were areas around the house where nothing was growing but a spreading, raggedy little aloes. Our first instinct was to remove them and replace them with native plants. But we had 10 acres to take care of and didn't get around to it until winter. Flower stalks were pushing up by then. Coral red and delicate, but braving night freezes and drought. The hummingbirds loved them...so did we.

Our neighbor Thea brought us a trunk-full of plants from her garden, mostly cactus clippings and agave pups, but also a different species of aloes. These were taller, not spreading, and in March, they produced long lasting yellow flower stands. The Gila Woodpeckers delicately extracted nectar ... and we were getting hooked on aloes.

 At the Boyce Thompson Arboretum and at Tohonochul Park we discovered larger species like Aloe ferox. The friendly owner of Bach's nursery gave me a free six-pack of rather overgrown, root-bound Aloes that would become some kind of tree-aloe if they survived. Two got eaten by bunnies, one was too far gone when I got them, one froze during another cold winter, but two did get so big that Randy started calling them Audrey. Right now, they are about 5.5 feet high, including the flower spike.

Aloe marlothii
The botanical name is Aloe marlothii, or Flat Flowered Aloe. According to an online source  they are hardy to 20 degrees F. This winter severely  tested that, but they both survived several nights of 18 degrees. While most of the fleshy leafs lost their tips to frost burn, the rapidly growing flower spike never even seemed to slow down. 

Bullock's Oriole

The flowers open slowly, starting at the bottom, and for the next two weeks, there will be new ones every day. Traveling Bullock's Orioles can use the refreshment on their trip north.

Hooded Oriole
They have to fight the just returning  Hooded Orioles for it, and these usually win. Here's a link to  our resident male enjoying his treat.

Gila Woodpeckers also like the tree aloes
 Aloes are natives of Africa. They may look similar and are adapted to similar arid, hot, sandy habitats as our local agaves,  but the two genera are only very distantly related. Aloes bloom every year and not just once in a lifetime like their American counterparts which makes them great for a desert garden with little color in early spring. (but we do have great penstemons also)

Since birds and insects don't seem to discriminate against the transplants, we enjoy seeing them blooming in our yard when little else does. But we keep them confined to the 'gardeny' part of our land close to the house. We collected some seeds from each blooming cycle. The seedlings are now 3 (right) and 2 years old and still in pots on the window sill.

On the outlying parts of out property, we preserve and plant strictly native vegetation, even avoiding Mexican and South American succulents and cacti. As a result, we got through the cold spell of the last winter with minimal losses and it is great to see how everything is getting ready to bloom now.
                                           All we need is MORE RAIN!!

Thursday, March 17, 2011

Mating Season for Urban Raptors

Old Main of the University of Arizona
It's spring break. The campus of the University of Arizona is eerily quiet for this week. But every morning when I pass the big old pines framing 'Old Main' I am startled by a crescendo of loud, nasal bird calls.
Today I watched as a small male Cooper's Hawk carried his prey first to the trees at the fountain, listening to his mates impatient  'gna-gna-gna-gna-gna' call, stepping from one foot to the other and waving his bent neck indecisively from left to right.

Then he finally flew across my head to join his mate on a big branch right in front of the windows of the Social Sciences building.  Impressive how much larger the female is! By the time I finally remembered that I was packing (a camera) today, the prey had already changed owners and the little male was about to go hunting again. The female devoured every bite of the gift and had no objections to my filming.

Again, the flickr quality is much better, so please click here to see her feast.

This courtship feeding obviously plays a role in the bonding of the pair. It also allows the female to judge the hunting capabilities of her mate. This will soon be very important when she is tied to the nest for laying and incubating the eggs and also later when she stays with the young nestlings to feed them the prey that the male has to deliver.  Only when the nestlings are quite grown does the female start hunting again - and then she goes for much larger prey than the male.

Now I'm hoping to observe these two nest on campus. They will have to deal with much more traffic when the students are back, but I remember an Osprey pair on the U of Florida campus in Gainesville, that every year raised their young successfully. Of course, their nest was guarded by the  campus pond gator.

Wednesday, March 16, 2011

Under dry Cow patties

Spring is close here in the Sonoran Desert, but this year, there are hardly any flowers or fresh leaves yet. But by now I get desperate for small critters to photograph. So I turn over old, dried-out cow dung. There is very little wood on the ground and rocks are neatly embedded into the loose desert sand. So old cow pies is where everybody is hiding!
Today I found spiders and scorpions, centipedes, termites, some few caterpillars, true bugs, weevils and ground beetles. Once last year I found a really rare Oil beetle.

Today's nice surprise was a vertebrate: A Western Banded Gecko. He was very patient with me exposing him to the sun for a few pictures and a video. Usually they just scuttle away into the darkest corner they can find. This one was big enough to be fully grown, but like many of his kind in southeastern Arizona, he had retained the juvenile banded pattern. Western Arizona relatives sport rows of spots rather than bands.


I uploaded the videos to flickr, because I got the impression that the quality is better than if I load it directly to the blog. It's still just one click away, enjoy!

Tuesday, March 15, 2011

I yelped, but I didn't flinch

Edrotes ventricosus, a confirmed vegetarian. Or is he?

Monday, March 14, 2011

Darkling beetles (Tenebrionidae) in the Dunes of Western Arizona

 At the end of February, Charlie O'Brien and I went on an early collecting trip to the dunes of western Arizona, from Yuma and San Luis in the south to Parker and Bouze in the north. After the cold spell in early February,  desert annuals were only sprouting and most bushes and perennials were just coming out of  dormancy.

Dune along the Gila River north of Yuma

Besides Charlie's target group, Curculionidae,  we found mostly Tenebrionidae or Darkling beetles. In American Beetles, Vol 2, Chapter 106, the authors describe the Tenebrionidae as highly evolved and diverse. In fact, they state that because of the many exceptions that exist in most diagnostic characters, these beetles are often difficult to recognize as a family. A tarsal formula of 5/5/4 and a facial ridge covering the base of the antennae is common to most, but not all of the family members. On the other hand, many beetle collectors assume jokingly  that any beetle that doesn't obviously conform with any other family is is most likely a teneb (nick name for Tenebrionidae). The following links represent some examples from Bug Guide, showing tenebs looking deceivingly like June Bugs (Scarabidae), Ground Beetles (Carabidae), Flat Bark Beetles (Silvanidae), and even Lady Bugs (Coccinellidae).

Below is an assortment of 'typical' Tenebs from Arizona.

Some Arizona Tenebs (not to scale)

With 20,000 species, Tenebrionidae populate most parts of the world. They feed on fresh and decaying plant material, which includes grain products in human storage. Easy to raise and feed, adults and larvae (meal worm) have become popular as laboratory animal models and as  food sources for insectivores in captivity.

Tenebs occupy moist forest floors and dark corners under rocks and bark of decaying wood and are freeze resistant or  freeze tolerant even during arctic winters. But undoubtedly, this family found most of its adaptive niches in hot, arid and sandy habitats. Very striking adaptations can be found from the Mediterranean to south African and Asian deserts and of course also in the Sonoran and Mohave Deserts of Arizona.

Eleodes longicollis, Madera Canyon
Surprisingly, many of these desert species are dark and easy to spot on the light sand, especially since most of them become active by early dusk.

Tenebs use several strategies to deter predators. Besides being very good at playing dead, many of them can emit a pungent smell. They announce with a clear behavioral  signal (head stand) when they are going to use this chemical defense. The avoidance reaction of predators must be strong, because there are several non-teneb dark desert beetles that join in on this defense  with Muellerian (Ground Beetle Calosoma peregrinator) and  Batesian (Cactus Longhorn Moneilema) mimicry. To humans of the Southwest, the teneb species are generally known by the popular names Stink Beetle and Pinacate Beetle.

Meal leftovers of a Grasshopper Mouse 

Still, some predators do specialize in hunting the big beetles as a substantial prey. Coyote scat and Sonoran Desert Toad droppings are often full of their exosceletons. Grashopper mice simply stuff the offending hind end of a Stink Beetle into the sand and then chew off its front portion.

Eleodes armatus stored by a Shrike

Most birds do not have a well developed sense of smell. A shrike took this Eleodes armatus and stored it on a pointed branch for a later meal.

Interestingly, the beetle's head-stand that serves as a warning to predators here in Arizona is used by Namibian Tenebrionids to collect fog-moisture. Our local beetles, also suffering from water deprivation, may or may not employ the same mechanism, but dew and fog are  less common here than in the coastal South African desert. Instead, all teneb bodies are superbly built for water conservation. Collectors soon learn how well the carapax of a teneb prevents evaporation even after death. While all other pinned beetles of the same size are long since dry and ready to be stored in insect drawers, the legs of pinned tenebs seem to remain endlessly flexible and the retained moisture sometimes causes the insect pins to rust and break.

Edrotes ventricosus, Mohawk Dunes, Yuma Co.

Shapes approaching  the ideal of a round disk or better yet, a sphere, optimize the surface to mass relation in Eusattus and Edrotes species and thus minimize water-loss.

Eusattus reticulatus, Molino Basin, Catalinas, Pima Co.

Eusattus dubius arizonensis, Kofa, La Paz Co.

Interestingly, the Eusattus species from a moister location at a creek bed in Kofa is not quite as disc-shaped as the Eusattus reticulatus from dry, sandy areas of Molino Basin in Tucson.  

Asbolus verrucosus and Asbolus laevis

Some teneb species have thick wax coatings, but their smooth black relatives seem to be just as heat and aridity tolerant.

In dune habitats, many insect species burrow into the sand during the day to escape from heat and predators. Sifting dry sand through fine sieves is a successful collection method. The best place to start seems to be  the area around Burr Sage and Creosote bushes, especially under hanging branches that touch the soil.

Edrotes arens and Trichiasida hirsuta are covered in soft hair

Many of the insects found by sifting show special adaptations to burrowing in shifting dune sand.  We collected several species of Burrowing Bugs, Weevils and Darkling Beetles that are covered by coats of soft hair. This feature seems to help them to 'swimm' through the loose fine sand while keeping the grains from clogging the tracheal openings (spiracles) needed for respiration.

Cnemodinus testaceus and Notibius puberulus

  The tibiae of these little tenebs found by sifting under Creosote bushes show adaptations to their burrowing lifestyle. The tibiae of Cnemodinus remind of the dentate tibiae of many Scarabs that also burrow underground during the day. Notibius also has widened, shovel-like tibiae.

From left to right: Helops sp., Embaphion depressum, Helops sp., Parasidina hispicula, Metoponium ? sp.
A single Parasidina hispicula under dead wood and several Blaps and Helops-like beetles caught in a pit trap,  plus the  elegant little Ambaphion depressum that was found dead,  brought the number of teneb species for this early spring dune trip to thirteen. Not bad for an area with on-going night-time freezes, still nearly devoid of fresh vegetation.

I like to thank Prof. emerit. Charlie O'Brien who knows all the locations and who did all the driving and sifting, and Kojun Kanda Ph.D. and Aaron Smith Ph. D. for their help with identifications.