Ranatra is the most widespread of America’s three genera of waterscorpions, with 10 species distributed throughout the country. The flattened, leaf-like Nepa contains only one species, N. apiculata, which is found only in eastern North America. It resembles a small giant water bug with a respiratory tube projecting from the tip of its abdomen. The third genus, Curicta, also a leaf mimic, is intermediate in form between the thin, cylindrical Ranatra and the broad and compressed Nepa. Curicta is known primarily from Mexico, Central and South America.

I first became acquainted with Curicta in 1996 while working at SASI. Steve Prchal, Randy Morgan, and I set up a 100-gallon freshwater aquarium for insects, including a half dozen or so Curicta collected in Sonora, Mexico. After introducing these and other aquatic denizens to their new home we all sat around the tank in a semicircle as if it were a flickering campfire. We were completely entranced by the backswimmers, water boatmen, and sunburst diving beetles as they settled into their new home. But it was the unfamiliar and stocky waterscorpion Curicta that captured my imagination and I was determined to find out more about them.

To my surprise, I discovered that Curicta was known from southeastern Arizona. Three specimens had been collected in the Huachuca Mountains back in 1899. These specimens were deposited in the Snow Entomological Museum at the University of Kansas and were thought to be identical to the species found in Louisiana and Texas. My course was now clear; I began planning a visit the following summer to the Huachucas in search of more Curicta.

Later, while visiting the home of longtime SASI member Johannes Menzel in fall of1997, I came across a photo he had taken of Curicta. I assumed that he had photographed the beast somewhere in Sonora, but Johannes informed me that picture had been snapped in Bear Canyon in the Santa Catalina Mountains! Soon after I mentioned my quest for Curicta and Menzel’s photo to another SASI member, Chip Hedgcock, who confirmed that he too had heard of additional records from the Santa Catalina Mountains.

Armed with an exact locality, I headed up to Bear Canyon the following July with high hopes just days before attending the 1998 Invertebrates in Captivity Conference. The summer monsoons had already begun and I convinced myself that I was virtually assured of finding my quarry. However, much to my disappointment, the rains had not yet reached the Catalinas. The creek at the bottom of Bear Canyon had long since dried up and my searches up and down stream failed to locate any life-giving pools that would sustain aquatic insects of any kind. Discouraged, I drove back down the Catalina Highway toward Tucson, vaguely hopeful that my trip to the Huachucas the following month, 99 years after they were first discovered there, might turn up Curicta.

Almost a month later I drove through the gates of Fort Huachuca with my good friend and odonatologist Rosser Garrison to search for damselflies, dragonflies, and Curicta. As we wound through the fort and entered the mouth of Garden Canyon I began to imagine the elusive waterscorpion basking in small numbers here and there along on the bottom of semi-permanent stream that flowed along the canyon bottom.

We drove past the picnic area and headed up the canyon, parking along the side of the road at what seemed to be a likely spot located near the small, cold water stream. The watercourse was lined with smooth boulders and punctuated by tufts of green grass and spiky patches of horsetails. Tall oaks and thick clumps of willows growing along the stream shaded the canyon bottom, making the search for Curicta difficult. The sunlight continued to deteriorate as thick, dark clouds gathered overhead, fueling yet another afternoon monsoon.

After about two hours I had to abandon my fruitless search. The thunderheads that had been accumulating overhead finally dumped their load of moisture. All around me the milky red runoff cascaded down the surrounding slopes and gathered in tiny rivulets that eventually snaked their way into the stream, robbing it of its clarity. The waterscorpions were apparently cryptic enough in clear water; now they would be completely obscured by the churning coffee and cream colored fluid coursing down the streambed!

I stood next to the churning torrent, soaked to the skin, admiring the power and intensity of the downpour. Within minutes, as the silt-laden stream began to swallow its grassy banks, the first Curicta appeared at my feet. Curicta! I had found it! Its dark chocolate body stood in stark contrast against the creamy water. And then I saw another. And another! And yet still another!

Suddenly flushed from their hiding places, dozens of Curicta were now clinging here and there to the mats of bright green grass for their very lives, trying desperately to keep from being washed downstream. As I picked up the waterscorpions many of them pretended to be dead and remained very still in my hand.

Utilizing my new and more accurate search image, I was able to locate more than 60 Curicta during the rest of the afternoon and the next morning, mostly adults. Some individuals were perched on rocks and plants, left high and dry by the receding floodwaters. The population appeared to be highly localized, occupying a single 40-yard stretch of stream; intensive searches up and down stream yielded only one small nymph.

I collected about 25 Curicta and carefully transported them alive to the Insect Zoo at the Natural History Museum of Los Angeles County. I set them up in a 20-gallon aquarium where they remained on display for several months. My new charges were fed a regular diet of mosquito larvae and pinhead crickets, but in spite of my efforts, they failed to reproduce in captivity. I learned later that, unlike Ranatra, which prefers to lay their eggs on vegetation and other floating objects, both Curicta and Nepa prefer to lay their eggs in mud. Still, I had every intention of publishing a short scientific note on the fact that they had been “rediscovered” in Arizona after nearly 100 years of obscurity!

As they died I packed up a few specimens and sent them off to my friend and colleague Bruce Gill at Agriculture Canada. He identified them as C. pronotata, a species described as new by Louis Kuitert, a graduate student at the University of Kansas. He had reexamined the original three specimens collected in the Huachucas in 1949 and determined that they were sufficiently distinct from the species C. scorpio from Louisiana and Texas, the only other species of Curicta now known to occur in the United States. Since I had inadvertently overlooked Kuitert’s description, I decided I had better conduct a much more thorough literature search before submitting my scientific note on the “rediscovery” of Curicta in Arizona. And it was a good thing that I did!

It turns out that Mark Dubois from the University of Kansas had found a lone male clinging to the side of a partially submerged log in Garden Canyon Creek in 1977 and published it in a note in 1978. Judging from Dubois’ description of the collection site, he was probably at or near the very same site where I made my “discovery” some 20 years later! And, just months after I had found Curicta, a paper by Jon Hoekstra of the Illinois Natural History Survey and Robert Smith of the University of Arizona appeared summarizing the distribution and habitat of C. pronotata in southeastern Arizona. Timing is everything!

Hoekstra and Smith confirmed the presence of Curicta in Arizona’s Huachuca, Galiluro, and Santa Catalina Mountains. They found both adults and nymphs abundant in Bear Canyon, along with the giant water bug Abedus herberti, among the woody detritus in shallow, rock-lined pools found along shady streams above 3900 feet (1200 meters).

The spotty distribution of Curicta in Arizona is probably an indication that this species is at the extreme northern limit of their distribution. Hoekstra and Smith contend that the species is rarely encountered in Arizona because of their spotty distribution, cryptic appearance, and tendency to feign death when disturbed. Further, populations of C. pronotata probably fluctuate greatly from year to year, especially in response to stream flow - or more importantly, a lack thereof. Since adults are fully winged it is likely that they are capable of flight, enabling them to escape vanishing pools and locate new habitats with food and egg laying sites.

I visited the Garden Canyon site again in 1999 and in 2002 and found the Curicta population still going strong. They were resting on submerged wood or along the muddy margins surrounding quiet pools lined with tangles of grass. Occasionally I would see them out of the water perched on a bank covered with grass, sitting motionless as if they were in the water. And in spite of persistent drought conditions in the Santa Catalinas in 2000, I managed to find a small, yet thriving population of adults and nymphs. They occupied several isolated pools that lined the mostly dry bottom of Bear Canyon like a string of pearls, just a stone’s throw from the Catalina Highway.

Selected references

DuBois, M.B., 1978. A recent record of Curicta pronotata Kuitert, (Hemiptera: Nepidae) from its type locality. Entomological News, 89 (7-8): 207.

Hoekstra, J.D. and Smith, R.L., 1998. Distribution and habitat of Curicta pronotata (Hemiptera: Nepidae) in southeastern Arizona. Entomological News, 109 (5): 366-368.

Keffer, S.L., 1996. Systematics of the New World waterscorpion genus Curicta Stål (Heteroptera: Nepidae). Journal of the New York Entomological Society, 104(3-4): 117-215.

Keffer, S.L. Taylor, S.J., and McPhereson, J.E., 1994. Laboratory rearing and descriptions of immature stages of Curicta scorpio (Heteroptera: Nepidae). Annals of the Entomological Society of America, 87(1): 17-26.

Kuitert, L.C., 1949. Some new species of Nepidae (Hemiptera). Journal of the Kansas Entomological Society, 22(2): 60-68.

Sites, R.W. and Polhemus, J.T., 1994. Nepidae (Hemiptera) of the United States and Canada. Annals of the Entomological Society of America, 87(1): 27-42.