Wednesday, July 27, 2011

The Yuccas of Cochise's Stronghold

Maybe you recognize the landscape from the many Western movies that were filmed here. It is also a place were dramatic real western history took place:when in the middle of the nineteenth century the Chiricahua Apache leader Cochise used this part of the Dragoon Mountains as his inaccessible retreat during his decades-long fight against the US military. Today a dirt road that has been greatly improved since I first drove up there in 1991 ends at a picturesque campground among granite boulders and Silver-leaf Oaks.

Urodera diliticollis and Megalostomis subfasciata

This years devastating fires had forced the closure of most Arizona wilderness areas. On July 17, the entrance to the campground itself was still barricaded but a nice ranger let us park off the road anyway.
Despite some showers that had interrupted our Beetle Bash black lighting the night before it was still extremely dry, with even the drought tolerant Manzanita bushes looking yellow and about to die.
But a few Acacias were beginning to green and even to flower, and several species of Leaf Beetles were getting the message: The monsoon is coming and life can only get better.

Agave pareyi

A dominant plant family at the stronghold are the Agavaceae. Molina Beargrass, Sotol, Agaves and Yuccas provided the Apaches with fibers for baskets, soap, starchy roots and stems and edible flowers and fruit. Agaves are succulent and build up resources for a spectacular, once-in-a-lifetime bloom over many years (hence the name century plants). Yuccas are not succulent, but protected against too much evaporation by the leathery surface of their leaves. Most have extremely long tap roots to reach water sources deep in the crevasses of the granite mountain side and bloom reliably every year.

Banana Yucca, Yucca baccata

The relationship of Yuccas and their only pollinator, the yucca moth (Tegeticula, Pronuba) is famous: The female moth collects pollen in a yucca flower, rolls it into a ball and stuffs it into the cup-shaped stigma of another yucca flower.While thus making sure the flower is pollinated, the moth also lays her eggs in the flower. The caterpillars will hatch and feed in the ripening fruit. They will destroy some, but not all of the many seeds each ovary produces. This is an example of obligate mutualism where none of the partners could procreate without the other. The moths are active at dusk, so we didn't find any during our visit.

Giant Agave Bug, Acanthocephala thomasi

The gorgeous, rich yucca flowers were attracting a number of other less specialized and less beneficial guests.

Giant Agave Bugs (Acanthocephala thomasi, a coreid true bug} were mating on the flowers. Nymphs of different ages were already around. It seemed that each group of nymphs was guarded by a parent.

Young nymph

Older nymph
All of them were using their sucking mouth parts to extract juices from the thick flower petals.

     A big green Stink Bug was also reluctant to give up his perch at the food source.

Green Stinkbug, Chinavia hilaris

The inside of another stand of creamy white flowers seemed strangely dark.

Epicauta ochrea

When I pushed the flowers apart, dozens of rust-brown blister beetles became visible. They seemed to be resting during the day, but frass patterns around them betrayed their nightly feasts on the yucca petals.

Glaucotes yuccivorus
An aptly named Longhorn beetle was sitting on the long pointed leaves.Yuccivorus means 'Yucca eating' and that is about all that literature has to say about this flat-faced borer that occurs only in Arizona (Texas?).

Hermetia comstocki

Hermetia concinna.

Soldier flies of several species kept landing on the leaves, maybe just using their spikiness as  protection against predators. While all resembled wasps, the one one the right was an exceptionally good mimic of Paperwasps - only her twitching antennae gave her away

Predators also made use of the three radial architecture of the yucca plant: certain spiders built their three dimensional webs between the leaves, and a young mantis was hunting in the bird safe sanctuary.

Stagmomantis limbata

Blooming Yucca, watercolor by M. Brummermann

Friday, July 22, 2011

Black Lighting in Peppersauce Canyon, Catalina Mountains

On the north side of the Catalina Mountains a service road connects the town of Oracle to the top of Mount Lemmon. Connecting may be the wrong term. None of my vehicles seems appropriate to negotiate the steep rocky, barely maintained road. The entrance to Peppersauce Canyon, however, is on the lower part of the road that is smooth and easy to drive. Last week Jeff Eble, a college from the entomology department, and two students asked me (and my black light) to join them on a collection trip. Jeff wants to study genetic shifts among isolated beetle populations of the sky islands, so he is mainly interested in flightless species that can't mingle as much as their more mobile counterparts.

Black lights, of course, draw the good fliers first. That evening, we were immediately inundated by hundreds of Phyllophaga vetula, a chunky, hairy June beetle. Scores of Anomala delicata followed soon after.

Soon a bristletail and a stick insect walked up, and a slim beige Mantis with surprisingly dark eyes, and a mantispid came to prey on 'our' bugs.

The most common Cerambycid was Methia mormona (top, middle), but we were also visited by a huge Prionus heroicus  (left), several delicately spotted Orwellion gibbulum arizonense  (right) and a tiny Sternidus decorus mMiddle, bottom). A number of Bycids in the the genera Aneflus and Oeme are still unidentified.

Weevils were represented by two Curculio spp (left). and the broadnose weevil Pandeleteius buchanani.

 Surprisingly several Sunburst Beetles Thermonectus marmoratus (right) and two Whirligig Beetles Dineutus sublineatus (left), all living in shallow ponds, showed up. We couldn't find any water close by, but the beetles are good fliers who often approach shiny surfaces like car roofs and lights.

The only carabids appearing in numbers looked like Selenophorus which we ignored because they are impossible to id. We also got several specimens of a tiny Bombadier Beetle that hopefully will be a new species for me. Jeff collected Lebia mimics of the Bombadier Beetles even though they do fly - he needs some control groups for his flightless stuff.

Walking along the trail with flash lights, we found two larger cerambycids, Enefalodes hispinicornis and a Prionid.  Both are good fliers, so I got them for my photo collection.

Jeff was happy with his collection of large flightless Darkling Beetles like Eleodes subnitens and longicollis on the trail, and Strongylium atrum (above) on tree trunks.

We also found several very attractively shaped Embaphion sp.  I hope to keep one of them alive and happy for the U of A Beetle festival on the 27th of September (Tucsonans, mark your calendars!).

Windscorpions (Solifugiae) were racing about at top speed, with Jeff in hot pursuit.

Under a rocky overhang an impressive  Cat-faced Orbweaver, Araneus illaudatus, was hanging out in her over 20 in wide net.

Meanwhile at the black light, interesting moths  had arrived: Clock-wise: Manduca rustica, Gerrodes minatea, Euclidia diagonalis, Syssphinx hubbardi, Datana sp.

While we were observing arthropods, fellow vertebrates were spying on us: A Woodhouse's Toad, two Gray Foxes and a gang of  Havelinas  took their turns.

Maybe we were set up right in the path of their evening rounds. 

Monday, July 18, 2011

Cochise County Roadside bounty

After this years Beetle Bash Eric Eaton and I explored the rocks and cliffs of Cochise Stronghold. I'll post photos and observations from this excursion another time. This blog will just focus on the very humble looking strip of vegetation along Ironwood Rd (none of those trees anywhere), the road that connects Cochise Stronghold in the Dragoons to the flatland of the Sulphursprings Valley.

 Along dry grassland, run-off from the road feeds a narrow green strip of Senna, Silverleaf Nightshade, little blooming gourds, a Zinnia species and stands of a fresh-green, knee-high Asteracea that wasn't blooming yet. On its slightly sticky leaves we found most of the insects shown below.

Altica sp. and Systena sp.
Little Flea Beetles (Alticidae) are at the bottom of the food chain and very difficult to identify.

Zygogramma piceicollis and a pair of Leptinotarsa decemlineata
Two of the larger leaf beetle (Chrysomelidae) species. The species on the right  is known all over the world as a potato pest, but there is evidence that our local populations, that live on small nightshades rather than potatoes, are genetically different enough to maybe offer some solution to the pesticide resistance of the potato bug.

Rainbow Grasshopper, Dactylotum bicolor        Toothpick Grasshopper, Achurum sp.            Horselubber Taeniopoda eques
The two on the left belong to the same family Acrididae, Shorthorn Grasshoppers, but could they be more different? The one on right is an early instar nymph of our big Horselubber.

Apiomirus sissipes and Apiomerus flaviventris

Two assasin bugs that are also called bee assassins, because they often hang out around flowers to grab nectaring bees. Even though nothing was blooming yet these guys seemed to make a good living hunting the abundant leaf beetles.

We found nymphs of different ages. The little one one the left is most likely A. sissipes which was most common among the adults (see the pair on the right). In the middle is an older nymph whose identity remains a mystery to me.

Juv. Phidippus sp.           Megaphorus sp.                  Argid Sawfly                 Anasa sp.                            Battus philenor
 Here are two more predators and some vegetarians: a jumping spider, a robber fly, a saw fly (wasp) a squash bug and the caterpillar of a Pipevine Swallowtail.  We found all of these just by walking along the road and looking, not using any swipe nets or beating sheets, so there probably were a lot more species that we missed.

Tuesday, July 12, 2011

The Arizona Queen of the Night, Peniocereus greggii

Two of my watercolors of the Night-blooming Cereus
Last night the Arizona Queen of the Night (Peniocereus greggii) bloomed in our part of the desert. Buds on all plants in our area simultaneously opened at sunset, the petals still growing and stretching outward for hours, until finally the dense anthers and star-fish-shaped stigma were presented above a skirt of slightly drooping petals.

I don't know what signal synchronizes this magical event. It's not day length, because it can occur any time between mid June and the beginning of August, and Tohono Chul Park 30 miles to the east celebrated the bloom about a week ago. The blooming is also rather independent of the onset of the rainy season, probably because the plants are drawing on the resources of a large underground bulb, although the hydration state of a plant seems to decide whether it's going to bloom in any given year at all. Sometimes, often following a very rich flowering, all the visible parts of a plant just dry off and crumble, and it takes years until the next flowers appear.

 The vegetative parts of this cactus are so thin and unassuming that 
they blend in completely with the branches of the Creosote bush. Our friends Frank and Lynn bought the land next to us years ago and were very much looking forward to the flowers of one Queen that we had planted, but we were all surprised by several other large plants that suddenly opened their flowers last night. 

The cactus flowers stay open into the early morning hours, so a couple of hours before sunrise Cody and I went out into the desert to find some more blooming Arizona Queens. At night usually a cloud of sweet fragrance is the first sign that leads pollinators and photographers to the plants. But at dawn, the pale flowers stand out like beacons. 

The flowers are about the size of a baseball. Many plants are not more than knee-high, but today I found several that were taller than I. This is impressive considering that a heard of cattle had a devastating 4 year run in this 400 acre parcel of state trust land. Wile the bovines destroyed Paloverdes, Prickly Pears and Ironwood trees,  they left the fragile stems of E. gregii untouched in their cover of Creosote branches.

This ten-flower cactus was the prize of the morning. I wished you could smell the cloud of sweet fragrance that surrounded it. This smell attracts the nocturnal sphingid moths that are the main pollinators of P. greggii. Big Manducas and the White-lined sphinx Hyles lineata are usually very common, but this year I have only seen a few at my black lights. 

When the moths are scarce unpollinated flowers probably stay fresh longer and their the beacon-like appearance at day break may insure visits by bees, although those promiscuous pollen gatherers are probably not the most reliable pollinators.

Saturday, July 9, 2011

Roadside Drama

Since there is no parking close to campus, I get a nice morning walk and a very hot afternoon work-out whenever  I'm working at the University of Arizona Insect Collection. It's an urban environment, but with very nice old established xeroscaping in the residential areas. After the first monsoon down-pour, even a fence made from ocotillo clippings sprouts fresh green leaves

I always have my camera ready for interesting  encounters. Cicadas are singing and huge Cicada killers are buzzing about, Carpenter Bees hover around palm trees...I've seen Trap-jar ants carrying Harvester Ants in their huge fangs. There seem to be more lizards in town than in the true desert environment at our home.

Sceloperos magister, Desert Spiny Lizard

Today a beautiful metallic blue wasp was searching for prey under a thick layer of mesquite pods that recent rains had deposited in the gutter. Eric Eaton confirmed from the photos: clearly a Chlorion species. So it belongs to the wasp family of the Sphecidae, the Thread-waisted Wasps. These solitary wasps either dig burrows to lay their eggs or build mud structures. They  provision their brood with life prey that is paralyzed by the wasp's sting. Their choice of prey is strictly species specific. (Of course there are exceptions: some are klepto-parasites, who they let someone else do the hunting and digging).

At first I assumed that this wasp was C. aerarium, the Cricket killer. The layer of nutritious, moist debris seemed like a very reasonable spot to look for crickets. The wasp was thorough, sometimes disappearing under leaves and seed pods, sometimes running around with its typical jerking, twitching movements.

A couple of times she came out onto the pavement as if to catch her breath, always returning to the same section of leaves and intently searching- she must have known that there was something hidden.

Then there was a rustling struggle among the leaves and the wasp finally bend her abdomen forward to carefully place a sting into something that her front legs and huge jars were pinning down out of sight. Now I know why she needs such a narrow bendable waist (petiole)!

After the sting, the wasp backed off, probably to wait for the paralysis to take hold. The prey that became visible was a surprise. No cricket at all, but a female Sand Roach. I had only once before seen one, in the dunes at Parker when Charlie O'Brien was sifting sand for weevils. But winged males of two species are commonly seen at porch lights around Tucson.

Female and two males of different species of local Sand Roaches in the genus Arenivaga
Anyway, the unexpected prey made me rethink the species ID for the wasp. There are two species of Chlorion in Arizona that are very difficult to tell apart in the field or from photos. But while C. aerarium feeds  crickets to its larvae, C. cyaneum hunts roaches for its brood. So my wasp can be safely identified as Chlorion cyaneum.
Chlorion arerarium, the Cricket Hunter

 To me, C. cyaneum looks bluer (kyanos, Greek, dark blue) than the verified C. aerarium specimen in my photo collection (above), but according to literature and specialists, that's not a good diagnostic character.

 Unfortunately my observations were abruptly ended by a group of students (isn't the semester over?)  jogging down the road. While my wasp had been very tolerant of my camera, she got spooked by so many stomping feet. Since I had no time to wait whether she would return to the paralyzed prey, and female Arenivaga Roaches are hard to find,  I collected the abandoned roach.