One of my greatest pleasures with collecting insects is not only the sights of the habitats that I visit, but the sounds. How many a night I’ve spent camped out in the Ozarks and watched royal moths fluttering at the blacklight sheet while dueling katydids traded their raspy “ch ch ch“s in the tree branches above and a whip-poor-will sang it’s haunting, eponymous song off in the distance. What joy to be hiking the canyon-lands out west and hear the musical, descending “t-te-tee-teee-teew-teeew-teeeew-teeeeew” of the canyon wren echoing off the tall, sheer rock faces. Even large-treed urban parks offer the hypnotizing “wee-er, wee-er, wee-er, weeeeeeeee” of scissor grinder cicadas (Tibicen pruinosa) on a hot summer night. Ah—cicadas! Few other animals can match their ability to fill a landscape with song, and with more than 100 species in North America it’s a safe bet that no matter where you go you can hear cicadas.
Cacama valvata (Uhler, 1888) | New Mexico, Harding Co., 5 mi W of Mills
Scissor grinders were the cicadas of my urban youth in Kansas City; I was a teenager the first time I heard the rich, pulsing buzz of bush cicadas (Tibicen dorsata) in the prairies around my house farther east in Blue Springs; and I experienced my first periodical cicada (Magicicada spp.) event as a young adult in St. Louis with Brood XIX and their whirring, “flying saucer” chorus. More recently, I’ve made several trips to the western Great Plains, where particularly large cicadas known as “cactus dodgers” (Cacama valvata) perch on prickly pear (Opuntia spp.) and cholla (Cylindropuntia imbricata) cacti and sing their loud, distinctive songs in the scorching, mid-summer heat. The male song has been described as a high pitched “metallic zing” (Beamer & Beamer 1930) or as an intense shrill, often in short bursts (Kondratieff et al. 2002); however, to me it sounds like a dull-bladed table saw cutting through a piece of ironwood and hitting a nail!
Cholla (Cylindropuntia imbricata, Otero Co., Colorado) is a preferred host for Cacama valvata.
Fast flying and alert, cactus dodgers often defy the attempts of collectors (Kondratieff et al. 2002) and have the amazing ability to usually land safely on their spined hosts without becoming impaled (although occasionally this does happen—see photo below). The perils of dodging cactus spines, however, seem to pale compared with the benefits of utilizing these widespread hosts, as the association appears to have facilitated the spread of the species into a wide variety of environments across the southern Great Plains and westward to California (Sanborn & Phillips 2013).
This female has a cactus spine impaled on her head.
The photos in this post were taken during late June 2014 in the scorching, cholla-studded, shortgrass prairies of southeastern Colorado and northeastern New Mexico. Given their alertness and fast flying capabilities, they were a challenge to photograph before eventually finding the somewhat more cooperative subjects shown in the above photographs. Eventually, I was lucky enough to encounter two individuals sitting on a dead cholla stem in the mid-afternoon heat near Vogel Canyon, Colorado, one of which (the lower) was singing (and thus a male) and the other I surmised to be a female (this I confirmed once I got a better look through my camera viewfinder).
A male Cacama valvata (bottom) sings to a female (top).
The male was creeping slowly towards the female as it sang, pausing occasionally and interrupting his song before resuming both. I presumed I was witnessing courtship singing, a behavior Kondratieff et al. (2002) have described in detail. They observed males perched on the ends of branches producing long, wavering, repeated shrills as they moved closer to the female. The song changed to a long shrill followed by shorter sequence of shrills as they made their final approach, which was followed by touching with the legs, mounting, and copulation.
Cacama valvata male singing.
Unfortunately for this male, the female was already in the act of oviposition (poor male—wasting his time flirting with a married woman!). In cactus, females oviposit almost exclusively in dry, dead, skeletonized stems and rarely utilize green material (Beamer & Beamer 1930). The eggs laid by this female might remain in the dry stem for another three months or more, where they will await a fall rainstorm to wet the stem and ground and bring cooler temperatures to improve their chances of survival before hatching, dropping to the ground, burrowing into the soil, and searching for roots upon which they can feed.
Cacama valvata female ovipositing on dead cholla stem.
Beamer, L. D. & R. H. Beamer. 1930. Biological notes on some western cicadas. Journal of the New York Entomological Society 38(3):291—305 [pdf].
Kondratieff, B. C., A. R. Ellingson & D. A. Leatherman. 2002. Insects of Western North America 2. The Cicadas of Colorado (Homoptera: Cicadidae, Tibicinidae). Contributions of the C. P. Gillette Museum of Arthropod Diversity, Department of Bioagricultural Sciences & Pest Management, Colorado State University, Fort Collins, 63 pp. [pdf].
Sanborn, A. F. & P. K. Phillips. 2013. Biogeography of the Cicadas (Hemiptera: Cicadidae) of North America, North of Mexico. Diversity 5:166–239 (doi:10.3390/d5020166) [abstract].
© Ted C. MacRae 2014