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Bugs and Ammo: Southern Arizona in Monsoon Season

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An impending monsoon storm over Saguaro National Park in Tucson, Arizona. The annual rains bring about a menagerie of insects and desert creatures. Biologist, zoo curators and private collectors consider the desert southwest one of the most diverse regions in the US. Lary Reeves

Before the monsoon rains lured me to southern Arizona, I had never been shot at. Nor had I seen wild rattlesnakes or the double-barreled mandibles of a sun spider. Certainly, I’d never been tailed by border control vigilantes or encountered a famous entomologist in a ghost town.

In July, waters from the sky return to this typically arid region. What seemed dead in June’s sweltering heat gradually comes back to life. The dun shafts of ocotillo plants burst with green leaves, and agaves bloom. Billions of ants take to the air in nuptial flights to mate, eggs of trillions more insects hatch, and grubs under logs pupate into shimmering beetles. This arthropodal feast brings out countless amphibians and reptiles, birds and mammals, and clouds of bats thick enough to block out the starlight.

It also brings humans, a diverse variety of the primates: Entomologists and bug-lovers of all stripes and striation; herpers looking for snakes and frogs; birders, bat-watchers and botanists. Tens of thousands of people come here during the monsoon for these activities, according to the Arizona Office of Tourism. Some choose to hike and photograph, some to wrangle rattlesnakes, and others to collect scorpions and spiders for private stashes or zoos.

In fact, most American zoos and insectariums with extensive invertebrate collections are either populated with descendants of this region, or owe a debt to the arthropod-husbandry experienced gleaned here. “Like moths to the blacklight we are drawn here each year,” says Jim Melli, an exhibition designer at the San Diego Natural History Museum who, like many making this annual migration, has an extensive knowledge of the area’s flora and fauna. “Rain in the desert brings it to life in a beautiful and mysterious way, and that’s the magic that brings people here.”

Melli is one of a couple hundred people who make the annual trek to the Invertebrates in Education and Conservation Conference. The meeting, which takes place in southern Arizona in late July, began in the early 1990s and attracts bug enthusiasts, zookeepers, educators and scientists from around the world. Attendees take in talks on such topics as how to best captively raise tiger beetles, a voracious coleopteran predator, and hear progress reports on subjects like the re-introduction of the endangered Taylor’s checkerspot butterfly to the Pacific Northwest. Vendors sell black widows and scorpions, ant queens and vinegaroons, a prehistoric-looking arachnid with claws and a whiptail that make it appear much more dangerous than it is. And an amiable, fast-talking man named Zack Lemann, chief entomologist at the Audubon Insectarium, can be counted on to make up arthropod-themed rap songs at a moment’s notice.

One favorite here is the pepsis wasp—a large, attractive insect with copper-colored wings also called the tarantula hawk (since it eats the large arachnids). These deadly hunters have the second-most painful sting in the insect kingdom. Entomologist Justin Schmidt, who came up with the Schmidt Pain Index for ranking the most agonizing insect stings, wrote that being pricked by one causes “immediate, excruciating pain that simply shuts down one’s ability to do anything, except, perhaps, scream.” He compared it to the feeling that “a running hair dryer has just been dropped into your bubble bath.”

Schmidt lives in Tucson and spends the monsoon season exploring nature. His passion and work are the same, he says; the excitement he felt upon first discovering a vinegaroon on a dark monsoon night was “beyond description.” I run into Schmidt while exploring a ghost town called Ruby with entomologist Lary Reeves and his girlfriend. The famous scientist, distinguished by a floppy green felt hat and a moustache, appears like something out of a dream, and then invites us to watch that evening as hundreds of thousands of Mexican free-tail bats come out to feed on insects.

After talking for a while, he gets out his net and snags a few velvet ants, which are also known to deliver nasty stings. He proceeds to thrust a jar into the net, and gently ushers the insect into it. “I’m one of the only entomologists to never use a killing jar,” he says. (Field biologists sometimes kill venomous insects in jars filled with substances like acetate, in part so they don’t get stung.) They probably helps explain why he’s been hit a handful of times by tarantula hawks and bullet ants, a tropical species that inflicts the most discomfort of any insect. “Pure, intense, brilliant pain,” is how he describes it. “Like walking over flaming charcoal with a 3-inch nail in your heel.”

Big Shots
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Photos: The Creatures of the Desert Monsoon

Images of the bugs, lizards and other animals encountered during Arizona's rainy season.
Launch Slideshow 9 PHOTOS

This part of the Southwest is where the Chihuahuan and Sonoran deserts, each with their own unique ecosystems, merge. Multiple mountain ranges give rise to “ sky islands,” housing diverse forests and meadows, and stretch into Mexico, providing corridors for tropical species. There is more biodiversity in the Sky Islands region than anywhere else in the U.S., says Shipherd Reed, the communications manager at the University of Arizona’s Flandrau Science Center.

The region’s geography also gives rise to the North American monsoon, whose mere existence comes as a surprise to many (who may be more familiar with the South Asian variety). A monsoon is characterized by a seasonal reversal in winds, along with a change in precipitation. Most of the year, winds blow into Arizona from the west and northwest. In the summer, especially in June, the region becomes extremely hot and dry. This creates a low pressure system that sucks in winds from the east and south, carrying moisture from the Gulf of Mexico, Gulf of California and the eastern Pacific. As the air is forced upward by various mountain ranges, especially the Sierra Madre Occidental mountains — which run northward like a spine up the western edge of Mexico — it drops rain. This water is reabsorbed into the air during the hot days and blown northward, gradually spreading the monsoon rain like a plume to the north and into Arizona and New Mexico. Both states can get up to half their yearly total of rain during the monsoon, which stretches from July to mid-September.

That’s why many tropical species occur here and nowhere else in the U.S. One such creature—found mostly in Mexico, besides a few rare spots in Arizona—is the lowland burrowing tree frog (Smilisca fodiens), a handsome brown-and-green amphibian that spends most of the year underground. It’s rare to hear its magnificent mating calls, uttered during a time of explosive activity during the monsoon season when it briefly comes above ground to breed.

When I arrive in Phoenix, around 10 p.m. on a Saturday in mid-July, Reeves and Trace Hardin, who runs a snake-breeding company, pick me up to go see these frogs, and search for a type of snake called a sidewinder that we end up not finding. There is a small wrinkle, though: they happen to live in the Vekol Valley. Cut off from the sprawl of Phoenix by mountains, and made up of federal and tribal land, this piece of the desert has become notorious as a corridor for drug and human trafficking — in 2010 several people, including a deputy, were shot here, and in June 2012 five bodies were found burned inside a charred SUV.

If you were to show up without having done any research, you’d get the idea pretty quickly; there are signs to dissuade you  from entering. “Danger - Public Warning: Travel Not Recommended,” declares a notice we pass, posted by the Bureau of Land Management. It further states that we are entering an “Active Human and Drug Smuggling Area,” and that “Visitors May Encounter Armed Criminals and Smuggling Vehicles Traveling at High Rates of Speed.”

But we don’t stop. Upon pulling into a spot where we will meet two others, my compatriots see something. “Rattlesnake!” exclaims Reeves, as he and Hardin jump out of the car. Reeves, almost done with a Ph.D. in entomology at the University of Florida, has a habit of chasing creatures whether he has a net or not; he often grabs them with his bare hands. Hardin shares this predilection for running after animals from which most people would flee; his Instagram account contains many photos of him holding snakes, often alarmingly close to his face.

The two laugh gleefully as they pursue and take photos of the snake, which is the exact color of the desert: a thousand and one variations of sandy brown. A few moments later, a car arrives with field biologist Aaron Chambers and one of his friends. Chambers is a large man with a deep tan who always wears tank tops, shorts and sandals, despite the prevalence of snakes and cacti. A fierce friend to those he likes, he says he "is only social during the monsoon season,” surrounded by like-minded naturalists. “At all other times, people can fuck off." He also carries a .38 handgun, and is extremely knowledgable about the area's fauna and flora. 

“That thing will ruin you,” Chambers bellows, before approaching to get a good look at the serpent. It’s a mojave rattlesnake (Crotalus scutulatus), the venom of which possess potent neuro- and hemotoxic properties, attacking nerve and blood cells.

09_18_DesertMonsoon_02 A Mojave rattlesnake, found by Lary Reeves and his team, in the lawless Vekol Valley. Lary Reeves

After a few more photos, we take off for a stream where the frogs live. We trudge through thick mud, leavened by cow pats from wandering cattle, and joke that in the dung-filled milieu we might contract hookworm. (Later, while changing out of my shoes, I accidentally step on a bombardier beetle, which shoots boiling-hot liquid out of its rear end onto my heel, staining my skin a reddish hue for weeks.) Soon we find Colorado river toads the size of small toasters. These are the United States’ biggest toads, and their skin contains psychoactive tryptamines than can cause hallucinations. Anthropologist Wade Davis describes the effects of smoking its venom this way: “Shortly after inhalation I experienced warm flushing sensations, a sense of wonder and well-being, strong auditory hallucinations, which included an insect-cicada sound that ran across my mind and seemed to link my body to the earth. Though I was indoors, there was a sense of the feel of the earth, the dry desert soil passing through my fingers, the stars at midday, the scent of cactus and sage.”

But we forego the psychedelic venom. As we approach a streambed swollen with rain, the call of our quarry—the burrowing tree frogs—becomes nearly deafening. Months and months of underground isolation now over, it’s time to mate. Reeves and Hardin spot a male, his vocal sac expanding like a membrane of bubblegum as he breathes. A few minutes later, a female hops by to check him out.

Several years ago, at this very spot, Chambers and his then-girlfriend were surrounded by a dozen or more vigilantes toting assault rifles, who assumed that he was a drug smuggler or immigrant. He told them he was an American citizen and carrying a gun. A tense standoff followed, but luckily no shots were fired, and everyone dispersed.

Militia-type movements have popped up in every state that borders Mexico; there are now more than a dozen formal groups that see it as their duty to try to keep immigrants from crossing the border illegally. U.S. Customs and Border Protection has publicly discouraged such activity; meanwhile, the agency apprehended 414,397 people unlawfully entering the country from Mexico in fiscal year 2013, an average of 1,135 people per day (or 47 per hour).

A few days after our frog hunt, we have our own interaction with militiamen. On a night when we probably should’ve been listening to the conference’s keynote talk about ants, five of us—me, Reeves, Hardin, Chambers and Isaac Powell, a keeper at Zoo Miami—hike out to look for insects in California Gulch, a remote part of the Coronado National Forest less than 2 miles from the Mexican border. When we arrive, we set up two intensely bright lights, powered by two separate generators, as well as a blacklight, to attract insects, a common entomological technique. We also set up a white sheet between them for the bugs to congregate upon. Soon thousands of insects have flocked to it: silk moths, beetles, adult antlions, flies and innumerable others. As we wait and sit back, watching, we enjoy local brews. “When you crack a beer, never get rid of the cap,” Chambers warns. “Otherwise, you're going to be eating a lot of bugs.”

After a while, the headlights of an SUV appear. The driver introduces himself as “Cody” and suggests we might be on his property. (We are certain we’re on national forest land.) Then the man tells us he’s a member of a militia; he shows us his hip-mounted pistol and an AR-15 he keeps in his truck, besides a skull-adorned mask worn while “on patrol.” After he leaves, an animated discussion begins, and Chambers makes his feelings clear about “rednecks who like to play G.I. Joe.”

Shortly thereafter, we see what looks like somebody’s headlamp coming toward us again, in the near distance. And then gunshots, four in rapid succession. I dive to the ground, moths fluttering about my head, as Chambers snaps off the generator. We pack up as quickly as possible and bolt.

The next morning, I wander around the conference bleary-eyed. “Things can get a bit crazy during the monsoon,” says a sympathetic zoo curator named Nate, who had heard about the previous night's encounter. “Too much alcohol, too little sleep, too many bugs.”

During our time in the desert, the entomologists make a couple of exciting discoveries. For one, they find a pregnant northern giant flag moth (Dysschema howardi), whose value Chambers estimates at $700, between what people are willing to pay for a dried specimen and its egg masses. They can be raised on romaine lettuce with little effort. We also come across the rare and venomous ridge-nosed rattlesnake (Crotalus willardi).

“I want to hold it so bad,” Hardin says. “This guy is just asking to be cuddled.” But with willardi, and other venomous snakes generally, even Hardin refrains. A few years back, a man was found dead in this area of the Huachuca Mountains, with three willardi on his person. The snakes once fetched up to $1,000 in Germany, although it’s illegal to capture them. Japanese dealers also once paid hundreds of dollars for rhinocerous beetles with large horn-like appendages found here called western Hercules beetles (Dynastes granti), Chambers says, recalling a past where the insects were sold out of briefcases in hotel rooms. But the Japanese figured out how to rear that beetle in captivity, and that trade has dried up.

Reeves decides to take home some sun spiders, arachnids that possess twin chelicerae, or fangs, that give them a fearsome appearance. Almost “nothing is known about these guys, and I'd like to start collecting material for a publication on them, down the road,” he says.

But they are also just amazing to behold for their own sake. One of the highlights of Schmidt’s early experiences in the Arizona monsoon, and a reason he moved to Tucson, was “seeing a sun spider, that buzz saw of a lightning-fast eating machine, in the middle of a whirlwind of flying moth scales.”