Tuesday, January 16, 2018

Javelinas in our Backyard

Our backyard gets visitors periodically, even though it's fenced as a dog run. They (the Javelinas) systematically uproot dozens of mamillaria cacti and eat the roots. So we pick up the buds and put them into sand-filled pots to reroot, then plant them for the next invasion. To get at least something out of it, I made the whole party pose for a painting.

 Even though they look deceivingly similar to wild boars Javelinas or Peccaries are only distant relatives of pigs. Taxonomically they are members of the same suborder, Suina, but are in their own family, Tayassuidae (New World pigs). They sport two pairs of big canines as opposed to just one in Oldworld Pigs.
But like pigs, they live in family groups, and root for their food with very similar snouts. As ours live in the desert, I never saw them enjoy mud baths, but our Arizonan, New Mexican and Texan Javelinas  live at the northern most tip of their distribution area which reaches all the way south to Argentinia. So they must use  many different types of habitats.
They are territorial and use skunk-smelling secretions of their  scent glands (below each eye and  on their backs) for marking and communication. If hunted for food, these glands have to be carefully and immediately removed or the meat is spoiled. I have eaten jerky and fresh, grilled tenderloin as guset of Mexican gold miners and it was very good.
Javelinas are rather nearsighted and also quite fearless, which results in frequent close encounters between them and human and caninen Arizona residents. Often the Javelinas just go quietly about their business. While house-sitting in the Tucson foothills at First Avenue, I once found myself surrounded by a herd  between garage and patio. They were so peaceful that I reached out to touch the big patriarch when he walked close to me. He screamed with indignation and bristled. Other people have been less lucky,  and those big canines leave bad wounds. My 40 pound Healer-type dog Bilbo got into a fight with a single Javelina last year, and he came away from it with a big, gaping chest wound. But at other times my dogs have cornered the entire resident herd including young ones and nothing happened. With Javies, you just never know.  So don't ever feed them, not even inadvertently by  keeping garbage or compost in accessible containers. The more the 'desert pigs' get habituated to humans and their houses, the more confrontations happen, and those usually end with killing or removal of the javelina herd, and our desert is all the poorer for it.

Sunday, January 7, 2018

Why is the sting of Velvet Ants so painful?

Dasymutilla  erythrina, D. gloriosa, D. sicheliana, all female
 First of all, though I have picked up many fast-running, wingless female Velvet Ants (Mutillidae, a family of wasps, not ants) to photograph them, my experience with their sting is all hear-say, as none of them ever tried to sting me. I've  also often swatted at males of nocturnal species that love to buzz around my reading light, but of course those males are stingless (the sting is the ovipositor)

Dasymutilla sicheliana male

Dasymutilla occidentalis (Cow Killer) from Eastern US, photo Barry Marsh
But the name cow-killer (a total exaggeration) and the bright aposematic colors of these insects that usually lead very unobtrusive lives on the ground, among sand and rocks, do hint at a potent weapon.  Justin Schmidt ranks their sting high in his sting index. High on the pain scale, but very low in duration or tissue damage.

Social wasps, Polistes sp. colony
 Among wasps and bees, most painful and harmful stings evolved in species that prey on very big, active and potentially dangerous prey that they send into an extended period of paralysis (tarantula hawk), or in social insects with lots of resources to defend. Nests of social wasps, bees and ants are sought after by many enemies because those nests offer a quite unique accumulation of proteins and carbs. Where else could a bear or a human village harvest  honey, pollen and larvae by the bucket? Of course, those social hymenopterans defend their riches with whole armies of rather expendable workers. The sting of these amazons is painful and often even harmful (tissue damage and central nervous effects) making sure that lessons are taught and remembered. Pogonomyrmex sp. Harvester ants, Fire Ants, Honey Bees, Yellow Jackets and Hornets are examples that most people know.

Mutillids are neither social nor do they store larval food or even have their own nests. Their larvae develop as Ectoparasitoids of immature insects, esp. bees and solitary wasps (also flies, limacodid moths, beetles, and cockroaches). So the mutillid wasp is not guarding or defending those nests or larvae. There are many other solitary wasps like Scoliids, Cicada Killers, and Mud Daubers etc. with comparable developmental histories that are not known for an especially painful sting.

Male nocturnal Mutillid
 And there is even more to the defense system of Mutillids: Velvet Ants squeak (stridulate) when grabbed or otherwise trapped - I know that from a male that crawled into my husbands ear while we were reading in bed - To me it sounded like Micky mouse and Donald duck got into an intense  argument in his ear-canal.  
Some species of mutillids also release chemical defenses when caught. In addition, all of them, winged males and fast-footed females, are so heavily armored that they survive unharmed when swatted at or stepped on - even when chewed on by a naive predator I assume. This extra strong exoskeleton must be costly to build and heavy to carry.  Justin Schmidt also mentions that the legs of a female mutilid are about as strong and muscular as insect legs can get. That's easy to believe when you see them running. So these wingless wasps have a defensive arsenal that is not equaled by many other insects.
Dasymutilla cirrhomeris
So why? Schmidt suggests a reason in his book The Sting of the Wild: Longlevity as a strategy.
The majority of insects has a very short adult life span. After mating, females of many species lay hundreds of eggs in one big clutch on a host plant and then die. Even big wasps like Cicada Killers that provide food for their offspring don't live much longer than 40 days. Mutilid wasps are parasitoids of solitary bees or wasps. Their arid habitats are bare and thinly populated by any host species. Mutilids procreate by placing single eggs into late instar larvae or pupae of their host species. So even if the female Mutilid finds a leafcutter nest with a series of larval chambers, there might only be one or two that fits her requirements. So her egg production may be strung out over a long time and depends on her searching for just the right situation to lay one egg or a few.  This is possible because her adult life span, amazingly, is longer than a year. This longlevity ensures that the female has time to place enough eggs to guaranty the survival of the species.  The arsenal of defensive weapons provides the means necessary to survive that long.

With Justin Schmidt and his family: searching for mutillids and other arthropods in the dunes along Blue Sky Road in Willcox, AZ in July of 2017
Thanks to Justin O. Schmidt for his excellent book 'The Sting of the Wild' John Hopkins University Press 2016,  for including my Mud Dauber, and for great company in the field!

Sunday, November 26, 2017

Beetle Talk for the Butterfly Society

On Tuesday, November the 28th at 7 PM, I am giving a talk about the Beetles of Arizona for the Tucson Butterfly Society at the Lutheran Church in the Foothills. Given that I am working on a book with that title together with Arthur V. Evans for years now, the topic is obviously one of my faves. I hope that the lep folks get excited about it too!

My 5 posters will be available after the talk: Butterflies, Moths, Arachnids, True Bugs and Beetles.

Sunday, October 22, 2017

We need Connections, not Walls!

Ocelot and Mexican Amberwing, watercolor October2017
 I live in Tucson, Arizona. 30.7 miles, or 50 kilometers, or 44 min by car from the US/Mexico border. In my dual role as artist and biologist I spend much of my time in the field. Tucson is surrounded by the Sonoran Desert. As deserts go, the lower Sonoran is beautiful and rich in geological formations and fauna and flora. But also hot and dry most of the year. The long drive to the Colorado Plateau and Grand Canyon in northern Arizona  would take me through the endlessly sprawling metropolis of Phoenix. So I turn south instead. The borderland to Mexico, studded with sky islands and the first hints of the Sierra Madre Occidental has become my favorite hunting ground.  I regularly join  excursions to study the biodiversity south of the border wit groups of US and Mexican naturalists and biologists. More often, and on my own, I spend time just north of the border. Long dirt roads connect the Canelo Hills and the San Rafael Grasslands, Parker Lake and Copper Canyon, Sycamore Canyon and Arivaca. Many side roads take me directly to the border fence. There are often heavy truck barriers, but they are low enough to step over. In other places, tall metal beams, set too close to each other to squeeze through, form a more impressive interruption of the landscape, but it still seems penetrable for small wildlife and cougars have been shown to jump it. In Lochiel, an old, nearly abandoned border town south of Patagonia, AZ, I used to pet Mexican horses grazing on the other side of an old chain link fence with big holes.  It's a quiet area, somehow suspended in time, and full of natural beauty.
It's not all paradise. In many areas along the fence, there is a wide gash in the vegetation, where border patrol erased every living thing to create a corridor for easy surveillance. There are strange contraptions that the agents can pull behind their trucks to sweep the ground so new tracks of border crossers show up clearly.   There is thrash that crossing people abandoned and sometimes clearly the packing material from drug transports. There are water stations that good Samaritans established because the harsh desert claimed so many lives. Very occasionally I meet people who approach me for help - who ask for water or need a charge for their phones. Or even a connection to the next agents of 'la migra'. The white, green-barred  SUVs of the border patrol agents are usually not far away, always cruising, waiting, watching ... but also often the last resort for people in need. The agents keep up the immigration restriction that US law dictates, but  so far, the situation is very different from what we experienced in the Europe of my childhood along the Iron Curtain and most of all the Wall and Death Stripe of Berlin. I can only hope that it stays that way.  

Saturday, October 21, 2017

Under a full Moon

Ringtail (Bassariscus astutus) watercolor, available
When you spend as many summer nights as I out in the canyons of Arizona and Mexico, you will sometimes hear rustling in the trees above, bumping noises on a roof or little chittering voices. Little faces with dark eyes under big ears peer at you from behind branches. They jump and climb with ease, trailing a long, luxurious tail, banded in black-and white. But since it's usually dark when ringtails show themselves, I never caught more than a glimpse.
At Carr house in the Huachucas we saw a regular visitor high on the roof, slipping in and out of the beam of our flash lights. Similar fleeting impressions were left by a couple of them very high up in a tree during a black lighting session in Ida Canyon further south. At my friend Pat Sullivan's and Lisa Lee's house I wanted to check the black light at the bug room one more time before sun rise and found myself face to face with the resident Ringtail who had had the same idea. We both jumped and he retreated.  Once I slept under the stars at the Madrone Ranger station in the Rincons - when I got up a Ringtail had just tucked himself into a crucked branch above my head to spend the day. Most encounters where ghostly and swift. No photos.
But during our August trip to the Sierra Juriquipa in Sonora Mexico one of our group, Steve Minter, wasn't giving up so easily. At nightfall, he saw a little guy watching him from a tree branch, so Steve climbed after the ringtail, up into the tree, camera and all. One name for Ringtails is Miner's  Cat, but in fact, the little racoon relatives are better acrobats than even cats. So why did it not run?  Steve was wearing a bright headlight - so maybe it was the 'deer in the headlights' effect or maybe the ringtail knew that the thinner branches would not support even the most daring human - anyway, the miner's cat stayed put and Steve got a number of nice photographs. This painting was inspired by them.

Ringtails are omnivores that feed on everything from bird eggs to berries, lizards and bugs. They like rocky areas with crevices  and cavities for their dens and they tend to live close to water. I keep thinking of them as typical southwestern animals, but they can be found from southwestern Oregon, south through California, southern Nevada, Utah, Colorado, Texas, Arizona, New Mexico, Oklahoma, eastern Kansas, Baja California and northern Mexico. I have sometimes seen a couple of them together, but those may have been litter mates or a female with a sub-adult kid. Normally ringtails live solitary in small territories. 

Wednesday, October 18, 2017

She loves me, she loves me not ...

'She loves me, she loves me not'   Peachfaced Lovebird Watercolor, October 2017
Finally back at the easel - no actually, I just made some room for my stretched paper next to my computer. Watercolors need to lie rather flat if you want to use any wet-in-wet technique.

The little gregarious parrots in the genus Agapornis were brought over from Africa for the pet trade. Escaped or released by unconscientious breeders, they found backyards and parks in the Phoenix area quite hospitable. Humans like them because they are pretty and their antics are entertaining. So the Love Birds find feeders and bird baths filled.  As cavity breeders, they appreciate the work of Gila Woodpeckers and Gilded Flickers. A peachy head poking out of a Saguaro cavity delights many valley (Phoenix) photographers. As a biologist I cringe, though. There is no telling yet what the impact of this invasive species will be. Can they adapt to real desert conditions and seriously compete with native Saguaro breeders? I got the impression that house sparrows (from Europe) manage to do so to a degree, while the European Starlings seem to stay around urban and agricultural neighborhoods and golf courses. This does not mean they are not depriving our endemic birds of prime 'oasis' living space. So far, the Peach-faces seem to stick to the Phoenix area and some backyard bird watchers in Tucson are clamoring to see them here. Tucson, with its proximity to the southeastern sky islands could be the jump-off point for the birds to colonize the sky islands. To me, a night mare.  So I love them (in Africa) and love them not (in Arizona).

Monday, October 9, 2017

Sycamore Canyon with Leslie, Sue and Curtis

In southern Arizona, October can still be a pretty good month for insect ans spider observations. So the four of us headed west on Ruby Road for Sycamore Canyon in Santa Cruz County.
Close to Pena Blanca Lake, Ruby Road turns into a dirt Road that winds its way up through the Atascosa and later the Pajarito Mountains.

Montezuma Quail
We spotted a family of Montezuma Quail by the side of the road - I think there was a dozen of half grown chicks hiding among the dry grasses. The male brought up the rear and posed nicely, but my macro lens was not quite up to the task.

Our target, Sycamore Canyon, extends from Ruby Road south towards the Mexican border. Many north-migrating arrivals, people as well as new insect species, enter the US here.

It's a lush, beautiful place, not the hard unforgiving desert that claims so many lives, but border patrol keeps a permanent presence. We met an agent peacefully lunching in the shade way up the canyon. We also came across a big cache of supplies for the greatest needs of human wanderers. 

Leslie Brown Eguchi and Sue Carnahan
This late in the year, the upper canyon was rather dry. Usually it's swampy and wet where Leslie and Sue are discussing a botanical question here. Several of the small water holes in the upper canyon were completely empty.

Further down, fish were crowded in little remaining ponds, but the rare chubb species that occur here are well adapted and can survive buried deep down in mud if they have to.

Neon Skimmer
Flame Skimmer

I think I saw my first Flame skimmers here years ago, and they were around again!  They mingled, or rather competed for perches, with their relatives, the Flame Skimmers. So we could clearly see their different coloration and also how the red extends much less into the wings of the Neon Skimmers. Obviously, the two species can be found sharing the same habitat.

Rhantus gutticollis,, Boreonectes sp, , Laccophilus fasciatus, Thermonectus nigrofasciatus,
Rhantus atricolor, Thermonectus marmoratus
In many places the water was not very deep, so aquatic beetles were easy to see and to catch. Several Sunburst Beetles shared one puddle with at least 5 other, less flashy species of Predaceous Diving Beetles.

Grasses and perennials setting fruit
Outside of the riparian zone, the grassland was yellow and most flowers had gone to seed. An army of black tenebrionid beetles was feeding on the starchy fresh seeds. Unlike their earthbound relatives, the crepuscular Pinacate Beetles, these smaller darkling beetles in the subfamily Pimellinae fly well and congregated not just to feed but also to mate among the wind-blown grasses.
Ericydeus lautus, Conotrachelus arizonicus, Zygogramma continua
Collops grandis, Lobometopon fusiforme or related Pimelinae, Phaenus quadridens
I also spotted some weevils (most are night active here in the desert). All conpostite genera seem to have their own, host-specific Zygogramma (Leaf Beetle) species. Many Melyrids (Soft-winged Flower Beetles) were out hunting - if I'm not wrong the larger Collops is feasting on a smaller Attalus in my photo. There was a small heard of black cattle watching our every move and noisily commenting on it. In the dung were mostly imported  Euoniticellus intermedius but I also pulled a dead Rainbow Scarab out of the mud at the creek.

Only very little water washed over my favorite bedrock area, but a dragonfly photographer was set up to patiently wait for a rare damselfly that had been reported from here recently.

Desert Firetails et al - Damseflies by Lealie Brown Eguchi
 We were just as happy to watch more ordinary species. The mating activity was still in full swing. Especially interesting was the mate guarding of most Damsel males that does not only allow the male to keep close control of 'his' female until their eggs are deposited, but also enables some females to safely submerse most of their bodies to place eggs in vegetation deep under the water surface.

Piezogaster spurcus and Pselliopus near zebra
Many true bugs were still active. Those 'suckers' seem to be especially well adapted to dry conditions. We also found water specialists in ponds and puddles: Gelastocoris oculatus (Big-Eyed Toad Bug) on the water surface and big, round Abedus herberti lurking well hidden in the brown water.

Phidippus octopunctatus and P apacheanus males

The activity time of the larger jumping spiders seems to be nearly over. Several females had sealed themselves in with their eggs - we saw hardly any silken retreats that were still open. A few males were still literally hanging out in the grasses.

Arctosa litoralis spinning electric blue silk?
Wolf Spiders raced and jumped among the moist leaf litter close to the creek and also skimmed over the water supported by nothing but surface tension. 

Tarantula Hawk
A Tarantula Hawk who was clearly at the end of her strenuous hunting life still ran and searched and twitched close to the wolf spiders. I think she would make do with one of them if she could. Not every Pepsis egg actually lands on a big tarantula.  Dwarf forms of big Pespsis species can often be observed and may result from unfortunate larvae that were left with just a small spider to devour.

Zenodoxus rubens Photo Sue Canahan
On our way home we stopped at the campground close to Pena Blanca lake, mainly so Sue Carnahan could identify the bush that has provided a number of interesting leaf beetles before. It turned out to be the Desert Honeysuckle Anisacanthus thurberi as expected. A nice Sesiid (Clearwing Moth) added a  last highlight to this late-season trip. The reported host of this moth (stem or root borere) is in the family Malvaceae, but it sure payed a lot of attention to the Honeysuckle