Shooting the Messenger

Monday, September 20, Malaysian government officials announced that they will not proceed with a planned release of genetically modified Yellow Fever Mosquitoes, Aedes aegypti (pictured below, on *me*), in rural and wild regions of that nation (source: Malaysia Today.com). The mosquitoes have been “engineered” to produce short-lived larval offspring. This is obviously an attempt to prevent delivery of the disease-causing organism by eliminating its vector. What I find ironic is that there are concurrent efforts being made to engineer malaria mosquitoes (genus Anopheles) that are non-lethal to the insects, but prevent them from being viable intermediate hosts to the malaria parasite Plasmodium. Quite a contrast between the two strategies.

It can be argued convincingly that anything curtailing widespread mortality in “Third World” nations should be a high priority that will also aid in eliminating poverty. It can be argued that with current trends in climate change, tropical diseases will make significant inroads into temperate areas thus far free of such epidemics. It is also a fact that disease-causing organisms are developing resistance to antibiotics at an alarming rate. Why not shoot the messenger then: Attack the vector organisms responsible for ferrying those protozoans and other microbes.

The problems with killing off mosquitoes include a potential disruption of the food chain, whereby other organisms will be deprived of prey. Mosquito larvae also have their own role in filtering water. We cannot readily predict what the absence of mosquitoes would mean to ecosystems on even a local scale.

Interestingly, another article I read recently described how the “Brain tissues and the nervous systems of insects may provide the next line of antibiotic defense against emerging superbugs that have become resistant to drugs.” How do we know that the very cure for some of our human plagues doesn’t rest in the literal minds of mosquitoes? The point is that we haven’t examined all the possibilities. Before we assert a death sentence for a species, should we not mine it for all the “good” it could do? We are reticent to execute individual human criminals, perhaps in part because there might be something to be gained as a society by keeping them alive. We tend to be optimistic that way.

I tend to be optimistic about the most malevolent creatures we share the planet with. No creation, or product of evolution, is without some degree of merit, even if that grain of positivity has no direct bearing on human lives.

The “shoot the messenger” campaign has been seen before. Tsetse flies carry the trypanosomes responsible for sleeping sickness in humans, and “nagana” in livestock, especially cattle. Wild African mammals are immune to the disease, but serve as reservoirs for the parasite. Eliminate the tsetse flies and Africa becomes one big cattle ranch with no place left for wildlife. Is this an oversimplification? Perhaps, but the Law of Unintended Consequences factors prominently in cases like this.

We need to have meaningful dialogue about the direction that GM research is taking. The left hand needs to know what the right hand is doing, and profit from that information. I remain confident that we can overcome human mortality factors in a responsible manner that does not disrespect other creatures in the process. I still have faith that we can act responsibly in our own affairs of reproduction and population.

Update.

Once again I find myself apologizing for the relatively sporadic nature of my posts here lately. No excuses, really, though I have been working rather random hours at the Tucson Botanical Gardens, and consequently eating randomly, sleeping randomly, and writing randomly. Maybe I need to take a class on time management.

I also just concluded a project in which I reviewed chapters for a forthcoming self-published book on the natural history of Virginia Beach, Virginia, by Scott Bastian. He has been a delight to work with, and he will be turning out a pretty unique book that has a wealth of information stretching far beyond the locality of Virginia Beach. You'll hear more about this once it is off the presses.

A relative lack of rain this year in Arizona (except for the area immediately adjacent to the Mexican border) has meant that many insects have been lacking, or at least less numerous, than usual. Perhaps because the Tucson Botanical Gardens is heavily watered, I have found a surprising diversity of things there, and expect the trend to continue through October.

Best wishes to my readers for a fruitful fall of exploring, image-taking, and enjoyment of autumn colors.

Monsoon

Yesterday we had what was probably the last big storm of the “monsoon” season here in southern Arizona. I haven’t quite gotten used to the idea that we have monsoons. This isn’t Bangladesh. I have to take the television meteorologist’s word that the summer weather pattern qualifies as such.

During May and June, the Sonoran Desert heats up to an almost intolerable degree. Literally! Temperatures regularly exceed 100 degrees Fahrenheit. One year in recent memory we had a string of 39 straight days that were over 100 F. This simmering pattern sets the stage for what is to come. The winds change toward the end of June as low pressure replaces the fading high pressure, and moisture is drawn up from the Sea of Cortez. Rains usually follow.

Still, the definition of our Arizona monsoon seems to depend upon who you ask. Some say that when the dew point reaches 54 degrees Fahrenheit, it more or less marks the onset of the summer rainy season. The dew point is the temperature at which air becomes saturated with water vapor and that vapor begins to condense. Others simply assert that the average beginning of the monsoon falls on about July 7.

That is not to say that every monsoon is “average.” Far from it. Last year there was almost no rain at all, and this year has not been a great improvement. My immediate neighborhood has seen maybe three good storms with heavy rains. An average year would be more than double that.

The thunderstorms associated with the monsoons can be terribly violent. The storm yesterday included hail as well as rain, plus very gusty winds. A storm a few weeks ago spawned lightning that lit a tree on fire in a nearby park. Some streets here in Tucson are sacrificed to drainage during storms, and I jokingly tell people that I live on the North Fork of Magnolia during the monsoons.

Most destructive of the monsoon phenomena are “microbursts.” These are straight-line winds that can wreak just as much havoc as a weak tornado. Microbursts are essentially “wind bombs” that happen when cold air in the top of a thunderhead suddenly drops to the ground, sending the equivalent of a shock wave of wind in all directions. The winds generated can exceed 70 miles per hour, and the phenomenon can last from five to fifteen minutes. The area impacted is small, however, generally restricted to less than 2.5 miles in any given direction.

The intensity of the monsoon season varies considerably, and La Niña and El Niño events can exert quite an influence, but the rains are vital to preserving the diversity of flora and fauna in the Sonoran Desert.

Flickr Photostream

I admit I might be cheating a little, but today I am re-directing you to my Flickr Photostream for some eye candy. Each of the new images there includes a little bit of information about the creature depicted, and/or the circumstances under which it was imaged. Hope you enjoy. I'll be back soon with additional posts.

Brandi Fenton Memorial Park

Brandi Fenton Memorial Park is a multi-use holding of the Pima County Natural Resources, Parks & Recreation agency. I paid a visit there on June 15, 2010 and found it to be much more than I had anticipated. At a little shy of 57 acres, it is also far larger in size than I imagined.

The park’s namesake was a bright and cheerful 13-year old who died tragically in a car accident in 2003. The centerpiece of the park reflects in its landscape and architecture the joys of this vibrant teenager: butterflies, art, and a caring . A butterfly garden, fountain, several sculptures, and inlaid artwork make for a very colorful and inspirational community resource.

There is an equal abundance of active recreation opportunities to complement the passive, relaxing, and introspective areas. A dog park, basketball courts, fitness stations, playground, and walking paths afford exercise for people and pooches; and there are even equestrian facilities.

Additionally, there are many interpretive signs explaining the historical Binghampton district where this park is located. Original buildings remain on the property and serve a variety of public functions, including a visitor center. A farming community dating back to 1875, Binghampton is on the National Historic Register as well. Demonstration gardens of crops grown in that era are planned for the park in the future.

Located at the intersection of Alvernon Way, Dodge Boulevard, and River Road just blocks north of the city of Tucson, Brandi Fenton Memorial Park is a great place to explore and exercise your “inner child” (or your real son or daughter if you have a family). I look forward to seeing how the park matures (it opened in 2005) in the coming years.

Night of the Toads

I was fortunate enough to attend the annual Invertebrates in Education and Conservation Conference in Rio Rico late last month, and participate in a couple of the spontaneous field trips that happen, especially after dark. One such excursion, led by my good friend Zack Lemann of the Audubon Institute Insectarium in New Orleans. We were looking for certain beetles, and had success, but reptiles and amphibians were also in abundance. Chief among those were toads.

We drove north from the conference headquarters in Rio Rico toward Madera Canyon, stopping at a service station at an exit in Green Valley. There, right by the interstate, we found the cactus longhorn beetles Zack was after, but there were also several Couch’s Spadefoots (Scaphiopus couchi) dining on the many insects drawn to the lights of the gas station.

Spadefoots are technically frogs in the family Pelobatidae. They lack the large parotoid glands of true toads (located just behind the eyes and visible as large, elliptical bulges). What truly sets them apart from other amphibians, however, is the dark, hardened tubercle on the underside of the heel of each hind foot. These “spades” help the animal dig into and out of the mud.

Couch’s Spadefoot is exceedingly tolerant of long dry spells, emerging during the soaking monsoon downpours that typically begin in early or mid-July here in the Sonoran Desert. They erupt from low-lying areas as those ditches and depressions fill with water and soak into the soil, softening it. The spadefoots have been buried fairly deep in the soil awaiting the rains.

Males call to females with a voice that has been likened to a “bleating sheep with a cold.” Real attractive. It works, though, at least on female spadefoots. Females lay eggs in the temporary puddles and the ova hatch twelve to twenty-four hours later. The tadpoles, in a race against the evaporation of their aquatic niche, metamorphose to miniature adults in as little as eight days. Before the mud dries and cracks, the spadefoots dig in. Underground they are able to tolerate at least a year without food or water until the rains once again return.

From Green Valley, our party moved on to a retirement community in the small town of Continental. The lights in the parking lots of the community attract many insects, and not surprisingly toads are wise to this fact. Under one light I found this Great Plains Toad, Bufo cognatus.

I am grateful that the toad was quiet, for I have read that the calls of males are lengthy, extremely loud, and likened to a jackhammer. Unlike spadefoots, members of the genus Bufo are true toads in the family Bufonidae, characterized by “warty” skin and those prominent parotoid glands. Otherwise, the life cycle and habits of the Great Plains Toad closely resembles that of Couch’s Spadefoot. The tadpoles take longer to mature, but the adult toads likewise spend the bulk of their lives underground awaiting heavy rains. They make the most of their time aboveground, eating a huge amount of insect and arachnid prey to get them through lean times.

Conspicuously absent from the landscape on this particular night (July 28-29) were the enormous Sonoran Desert Toads, Bufo alvarius that usually dominate the scene. Formerly known as the Colorado River Toad, this species has apparently been rendered extinct in much of the Colorado River corridor (along with the water which now does not even reach the Gulf of Mexico). These are huge animals, mature adults often measuring seven inches….in just about any direction so great is their girth. Some specimens would find a dinner plate a somewhat confining perch. They are not easy to photograph, either, as they turn away from flashes. I imaged this one in Picture Rocks.

Sonoran Desert Toads are nothing to trifle with, especially if you are a dog. They have incredibly toxic skin secretions. The hallucinogenic properties of those toxins are well-known to the medical community, too. Stupid people who engage in “toad-licking” get what they deserve. Pets that don’t know better can die from ingested toad toxins.

A really great online article about the Sonoran Desert Toad can be found here at The Firefly Forest website. Information about the other anurans (science-speak for “frogs and toads”) treated here can be found on the website of the Arizona-Sonora Desert Museum.

Sources:
Brennan, Thomas C. & Andrew T. Holycross. 2006. Amphibians and Reptiles in Arizona. Phoenix: Arizona Game & Fish Department. 150 pp.
Hanson, Jonathan and Roseann. 1997. Fifty Common Reptiles & Amphibians of the Southwest. Tucson: Southwest Parks and Monuments Association. 63 pp.

The Better to Hear You With

That passage from “Little Red Riding Hood” could apply as easily to Townsend’s Big-eared Bat, Corynorhinus townsendii, as it does to the Big Bad Wolf. This docile little creature is not nearly as menacing, however, and a true friend to farmers and other folks plagued by insects.

I was fortunate enough to discover this roosting individual inside an abandoned house in Brown Canyon on the Buenos Aires National Wildlife Refuge in southern Arizona. Thanks to Philip Kline who had informed me of another species of bat in the same house. That bit of knowledge prompted me to venture into what had to be Hanta Virus Central to try my own luck. I found the solitary Townsend’s Big-eared Bat as a result.

Townsend’s Big-eared Bat occurs chiefly west of the Rocky Mountains from southern British Columbia through Mexico, but isolated populations in the Ozark Plateau and Appalachian Mountains are not thriving. Like most bats, this species is incredibly sensitive to any disturbance during hibernation in caves, mine shafts, and similar locations.

Those big ears come in very handy when the bat is hunting. Most insect-eating bats use echolocation to pinpoint their prey in flight, homing in on the audible signals bouncing off their moving target. Big-eared bats have raised this hunting style to an art form, and few moths can escape these nimble fliers.

This species roosts singly during the day in the summer months, but individuals cluster together during winter. Mating happens in late autumn or early winter, and each female gives birth to a single offspring in May or June. Maternity colonies can include several dozen to a few hundred females.

Look for this species in desert scrub or dry pine forest habitats for the most part. Note that many references still list it by its older scientific name, Plecotus townsendii. Besides the extra long ears, often folded back as the one ear in the image above shows, this bat is recognized by the pair of glandular bulbs that rise above the nostrils.

Additional sources of information include this great page by Texas Parks & Wildlife, and this page from Pima County government that likely addresses the subspecies imaged above since Brown Canyon is in the Baboquivari Mountains (pronounced Bab-o-KEEV-er-ee).